Compositions and methods for transferrin receptor (TFR) mediated brain and muscle delivery

Abstract

The present invention provides, in part, protein-drug conjugates comprising an anti-transferrin receptor (e.g., human transferrin receptor) antigen binding protein (e.g., scFv, Fab) conjugated to a molecular load (e.g., a polynucleotide, liposome, or lipid nanoparticle) for delivery of the molecular load to a target tissue (e.g., brain or muscle). Methods of treating various diseases or disorders, such as neurological or muscular diseases, with the conjugates are provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 393,749, filed on July 29, 2022, which is hereby incorporated by reference in its entirety.

[0003] Sequence Listing

[0004] This application contains a sequence listing that has been submitted electronically in XML file format and is hereby incorporated by reference in its entirety. The XML copy, created on July 26, 2023, is named 250298000507SEQLIST.XML and is 547,729 bytes in size. Technical Field

[0005] The present invention relates to protein-drug conjugates comprising an antigen binding protein conjugated to a molecular cargo, and methods of treating disease with such protein-drug conjugates. Background Art

[0006] Iron is delivered to the brain via the combination of iron-binding protein transferrin (Tf) and intracellular transport. Tf receptor (TfR) is the target of some researches of drug delivery to brain. For example, method includes using liposomes modified with Tf, for delivering developer and DNA (Sharma et al., (2013) Cell penetrating peptide tethered bi-ligandliposomes for delivery to brain in vivo:biodistributionandtransfection.J.Control.Release 167,1-10), or using iron mimetic peptide as part (Staquicini et al., (2011)).

[0007] A correlation between increased antibody affinity and lysosomal degradation has also been proposed (Bien-Ly et al. (2014) Transferrin receptor (TfR) trafficking determines brain uptake of TfR antibody affinity variants. J. Exp. Med. 211, 233-244), which supports the view that lower antibody affinity will help to avoid intracellular degradation of the transported complex. Bien-Ly et al. found that a bispecific antibody against TfR and β-secretase (BACE1) crossed the blood-brain barrier (BBB) ​​and not only effectively reduced brain amyloid β protein levels; but also high-affinity binding to TfR caused a dose-dependent decrease in brain TfR levels. Similarly, Moos and Morgan (2001) compared the ability of the anti-TfR antibody OX26 and transferrin to cross the rat BBB and found that OX26 was not recycled from the brain like transferrin because the antibody exhibited a high-affinity antibody-antigen interaction with TfR that was not easily reversed, while this effect of Tf was easily reversed depending on the pH and iron content of Tf (Restricted transport of anti-transferrin receptor antibody (OX26) through the blood-brain barrier in the rat, J Neurochem 2001 Oct;79(1):119-29). Summary of the Invention

[0008] In one aspect, provided herein is a protein-drug conjugate comprising an antigen binding protein that specifically binds to human transferrin receptor (TfR) or a variant or antigenic fragment thereof, conjugated to a molecular cargo.

[0009] The antigen binding protein can be expressed with a K of approximately 41 nM. D In some embodiments, the antigen binding protein binds to the human transferrin receptor with a K of about 30 nM or greater, such as an affinity of about 20 nM or greater, an affinity of about 10 nM or greater, an affinity of about 5 nM or greater, an affinity of about 3 nM or greater, or an affinity of about 1 nM or greater. d In some embodiments, the antigen binding protein binds to the human transferrin receptor with a K of about 0.45 nM to 3 nM. d Binds to the human transferrin receptor. Such binding affinity can be measured, for example, in a surface plasmon resonance assay at 25°C.

[0010] In some embodiments, the antigen binding protein may comprise a heavy chain variable region (HCVR or V H ) and light chain variable region (LCVR or V L ), and wherein the Fab having the HCVR and LCVR has a K of about 0.65 nM D or stronger affinity to bind to human transferrin receptor.

[0011] In some embodiments, the antigen binding protein comprises an antibody or an antigen binding fragment thereof. The antigen binding fragment can be selected from a humanized antibody or an antigen binding fragment thereof, a human antibody or an antigen binding fragment thereof, a mouse antibody or an antigen binding fragment thereof, a chimeric antibody or an antigen binding fragment thereof, a monovalent Fab', a divalent Fab2, a F(ab)'3 fragment, a single-chain fragment variable region (scFv), a double scFv, (scFv)2, a double-chain antibody, a bivalent antibody, a single-arm antibody, a mini antibody, a nano antibody, a three-chain antibody, a four-chain antibody, a disulfide-stabilized Fv protein (dsFv), a single domain antibody (sdAb), an IgNAR, a single heavy chain antibody, a bispecific antibody or a binding fragment thereof, a bispecific T cell engager (BiTE), a trispecific antibody, or a chemically modified derivative thereof.

[0012] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises an antigen binding fragment, which is a fragment antigen binding region (Fab).

[0013] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises a single chain fragment variable region (scFv). In some embodiments, the protein-drug conjugate comprises a single chain fragment variable region (scFv), which comprises domains arranged from N-terminus to C-terminus in the following orientation: heavy chain variable region (HCVR)-light chain variable region (LCVR). In some embodiments, the protein-drug conjugate comprises a single chain fragment variable region (scFv), which comprises domains arranged from N-terminus to C-terminus in the following orientation: light chain variable region (LCVR)-heavy chain variable region (HCVR). In some embodiments, the scFv variable regions are connected by a peptide linker. In some embodiments, the scFv variable regions are connected by a peptide linker, which is -(GGGGS)n- (SEQ ID NO: 426); wherein n is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. In some embodiments, the antigen binding protein of the protein-drug conjugate is at a density of about 1×10 -7 M's K D or stronger affinity to bind to human transferrin receptor.

[0014] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: (i) a HCVR comprising HCDR1, HCDR2, and HCDR3, and having a residue represented by SEQ ID NO: 2, 462, 12, 463, 22, 464, 32, 42, 52, 467, 62, 492, 72, 470, 82, 92, 472, 102, 112, 473, 122, 132, 142, 475, 152, 162, 477, 172, 182, 478, 192, 480, 202, 481, 212, 222, 232, 242, 252, 482, 262, 272, 282, 292, 302, 483 or 312 (or variants thereof); and / or (ii) a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: NO:7, 17, 27, 37, 465, 47, 466, 57, 468, 67, 469, 77, 471, 87, 97, 107, 117, 474, 127, 137, 147, 476, 157, 167, 177, 187, 479, 197, 207, 217, 227, 237, 247, 257, 267, 277, 287, 297, 307, 527, 317 or 484 amino acid sequence (or variants thereof).

[0015] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: (1) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 2 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 7 (or a variant thereof); (2) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 12 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 17 (or a variant thereof); (3) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 22 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: NO: 27 (or variants thereof); (4) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 32 (or variants thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 37 (or variants thereof); (5) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 42 (or variants thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 47 (or variants thereof); (6) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 52 (or variants thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: (7) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 62 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 67 (or a variant thereof); (8) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 72 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 77 (or a variant thereof);(9) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 82 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 87 (or a variant thereof); (10) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 92 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 97 (or a variant thereof); (11) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 102 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 107 (or a variant thereof); (12) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: NO: 112 (or variants thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 117 (or variants thereof); (13) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 122 (or variants thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 127 (or variants thereof); (14) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 132 (or variants thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 137 (or variants thereof); (15) a HCDR1, HCDR2 and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 142 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 147 (or a variant thereof); (16) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 152 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 157 (or a variant thereof);(17) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as shown in SEQ ID NO: 162 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as shown in SEQ ID NO: 167 (or a variant thereof); (18) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as shown in SEQ ID NO: 172 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as shown in SEQ ID NO: 177 (or a variant thereof); (19) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as shown in SEQ ID NO: 182 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as shown in SEQ ID NO: 187 (or a variant thereof); (20) a HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as shown in SEQ ID NO: 183 (or a variant thereof); R2 and HCDR3, and having an amino acid sequence as shown in SEQ ID NO: 192 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3, and having an amino acid sequence as shown in SEQ ID NO: 197 (or a variant thereof); (21) a HCVR comprising HCDR1, HCDR2 and HCDR3, and having an amino acid sequence as shown in SEQ ID NO: 202 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3, and having an amino acid sequence as shown in SEQ ID NO: 207 (or a variant thereof); (22) a HCVR comprising HCDR1, HCDR2 and HCDR3, and having an amino acid sequence as shown in SEQ ID NO: 212 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3, and having an amino acid sequence as shown in SEQ ID NO: 217 (or a variant thereof); (23) a HCDR1, HCDR2 and HCDR3, and having an amino acid sequence as shown in SEQ ID NO: HCVR having the amino acid sequence shown in SEQ ID NO: 222 (or a variant thereof); and LCVR having LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 227 (or a variant thereof); (24) HCVR having HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 232 (or a variant thereof); and LCVR having LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 237 (or a variant thereof);(25) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 242 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 247 (or a variant thereof); (26) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 252 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 257 (or a variant thereof); (27) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 262 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 267 (or a variant thereof); (28) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 1 ) a HCVR comprising an amino acid sequence as set forth in SEQ ID NO: 272 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 277 (or a variant thereof); (29) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 282 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 287 (or a variant thereof); (30) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 292 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 297 (or a variant thereof); (31) a HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: NO: 302 (or variants thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 307 or 527 (or variants thereof); and / or (32) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 312 (or variants thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 317 (or variants thereof).

[0016] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: (a) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 3 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 4 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 5 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 8 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 9 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 10 (or a variant thereof); (b) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 13 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 14 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 15 (or a variant thereof); and a LCVR comprising: a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 16 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 17 (or a variant thereof). NO: 18 (or a variant thereof), a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 19 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 20 (or a variant thereof); (c) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 23 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 24 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 25 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 28 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 29 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 30 (or a variant thereof); (d) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 33 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 34 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 35 (or a variant thereof); HCDR2 having the amino acid sequence shown in SEQ ID NO: 34 (or a variant thereof) and HCDR3 having the amino acid sequence shown in SEQ ID NO: 35 (or a variant thereof);and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 38 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 39 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 40 (or a variant thereof); (e) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 43 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 44 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 45 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 48 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 49 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 50 (or a variant thereof); (f) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 43 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 44 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 45 (or a variant thereof); NO: 53 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 54 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 55 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 58 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 59 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 60 (or a variant thereof); (g) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 63 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 64 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 65 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 68 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 59 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 60 (or a variant thereof). (h) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 73 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 74 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 75 (or a variant thereof);and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 78 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 79 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 80 (or a variant thereof); (i) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 83 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 84 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 85 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 88 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 89 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 90 (or a variant thereof); (j) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 83 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 84 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 85 (or a variant thereof); NO: 93 (or a variant thereof), a HCDR2 comprising the amino acid sequence of SEQ ID NO: 94 (or a variant thereof), and a HCDR3 comprising the amino acid sequence of SEQ ID NO: 95 (or a variant thereof); and a LCVR comprising: a LCDR1 having the amino acid sequence of SEQ ID NO: 98 (or a variant thereof), a LCDR2 having the amino acid sequence of SEQ ID NO: 99 (or a variant thereof), and a LCDR3 having the amino acid sequence of SEQ ID NO: 100 (or a variant thereof); (k) a HCVR comprising: a HCDR1 having the amino acid sequence of SEQ ID NO: 103 (or a variant thereof), a HCDR2 having the amino acid sequence of SEQ ID NO: 104 (or a variant thereof), and a HCDR3 having the amino acid sequence of SEQ ID NO: 105 (or a variant thereof); and a LCVR comprising: a LCDR1 having the amino acid sequence of SEQ ID NO: 108 (or a variant thereof), a LCDR2 having the amino acid sequence of SEQ ID NO: 99 (or a variant thereof), and a LCDR3 having the amino acid sequence of SEQ ID NO: 100 (or a variant thereof). (I) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 113 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 114 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 115 (or a variant thereof);and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 118 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 119 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 120 (or a variant thereof); (m) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 123 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 124 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 125 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 128 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 129 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 130 (or a variant thereof); (n) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 126 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 127 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 131 (or a variant thereof); 133 (or a variant thereof), a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 134 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 135 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 138 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 139 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 140 (or a variant thereof); (o) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 143 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 144 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 145 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 138 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 139 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 140 (or a variant thereof); LCDR1 having the amino acid sequence shown in SEQ ID NO: 148 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 149 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 150 (or a variant thereof);(p) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 153 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 154 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 155 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 158 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 159 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 160 (or a variant thereof); (q) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 163 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 164 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 165 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 158 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 159 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 160 (or a variant thereof); NO: 168 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 169 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 170 (or a variant thereof); (r) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 173 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 174 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 175 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 178 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 179 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 180 (or a variant thereof); and (s) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 181 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 182 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 183 (or a variant thereof). HCDR1 having the amino acid sequence shown in SEQ ID NO: 183 (or a variant thereof), HCDR2 having the amino acid sequence shown in SEQ ID NO: 184 (or a variant thereof), and HCDR3 having the amino acid sequence shown in SEQ ID NO: 185 (or a variant thereof);and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 188 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 189 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 190 (or a variant thereof); (t) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 193 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 194 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 195 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 198 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 199 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 200 (or a variant thereof); (u) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 193 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 194 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 195 (or a variant thereof); NO: 203 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 204 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 205 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 208 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 209 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 210 (or a variant thereof); (v) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 213 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 214 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 215 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 216 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 217 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 218 (or a variant thereof). LCDR1 having the amino acid sequence shown in SEQ ID NO: 218 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 219 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 220 (or a variant thereof);(w) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 223 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 224 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 225 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 228 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 229 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 230 (or a variant thereof); (x) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 233 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 234 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 235 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 229 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 230 (or a variant thereof). NO: 238 (or a variant thereof), a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 239 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 240 (or a variant thereof); (y) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 243 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 244 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 245 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 248 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 249 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 250 (or a variant thereof); and (z) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 243 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 244 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 255 (or a variant thereof). HCDR1 having the amino acid sequence shown in SEQ ID NO: 253 (or a variant thereof), HCDR2 having the amino acid sequence shown in SEQ ID NO: 254 (or a variant thereof), and HCDR3 having the amino acid sequence shown in SEQ ID NO: 255 (or a variant thereof);and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 258 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 259 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 260 (or a variant thereof); (aa) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 263 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 264 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 265 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 268 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 269 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 270 (or a variant thereof); and (ab) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 271 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 272 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 273 (or a variant thereof). NO: 273 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 274 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 275 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 278 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 279 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 280 (or a variant thereof); (ac) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 283 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 284 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 285 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 279 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 280 (or a variant thereof). LCDR1 having the amino acid sequence shown in SEQ ID NO: 288 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 289 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 290 (or a variant thereof);(ad) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 293 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 294 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 295 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 298 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 299 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 300 (or a variant thereof); (ae) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 303 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 304 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 305 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 298 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 299 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 300 (or a variant thereof); NO: 308 (or a variant thereof), a LCDR2 having the amino acid sequence set forth in SEQ ID NO: 309 (or a variant thereof), and a LCDR3 having the amino acid sequence set forth in SEQ ID NO: 310 (or a variant thereof); and / or (af) a HCVR comprising: a HCDR1 having the amino acid sequence set forth in SEQ ID NO: 313 (or a variant thereof), a HCDR2 having the amino acid sequence set forth in SEQ ID NO: 314 (or a variant thereof), and a HCDR3 having the amino acid sequence set forth in SEQ ID NO: 315 (or a variant thereof); and a LCVR comprising: a LCDR1 having the amino acid sequence set forth in SEQ ID NO: 318 (or a variant thereof), a LCDR2 having the amino acid sequence set forth in SEQ ID NO: 319 (or a variant thereof), and a LCDR3 having the amino acid sequence set forth in SEQ ID NO: 320 (or a variant thereof);

[0017] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: (i) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 2 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 7 (or a variant thereof); (ii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 12 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 17 (or a variant thereof); (iii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 22 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 27 (or a variant thereof); (iv) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 32 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 37 (or a variant thereof); (v) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 42 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 47 (or a variant thereof); (vi) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 51 (or a variant thereof); NO:52 (or variants thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO:57 (or variants thereof); (vii) a HCVR having the amino acid sequence set forth in SEQ ID NO:62 (or variants thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO:67 (or variants thereof); (viii) a HCVR having the amino acid sequence set forth in SEQ ID NO:72 (or variants thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO:77 (or variants thereof); (ix) a HCVR having the amino acid sequence set forth in SEQ ID NO:82 (or variants thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO:87 (or variants thereof); (x) a HCVR having the amino acid sequence set forth in SEQ ID NO:92 (or variants thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO:97 (or variants thereof); (xi) a HCVR having the amino acid sequence set forth in SEQ ID NO:102 (or variants thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO:103 (or variants thereof); (xiii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 122 (or a variant thereof);and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 127 (or a variant thereof); (xiv) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 132 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 137 (or a variant thereof); (xv) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 142 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 147 (or a variant thereof); (xvi) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 152 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 157 (or a variant thereof); (xvii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 162 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 167 (or a variant thereof); (xviii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 172 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: NO: 177 (or variants thereof); (xix) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 182 (or variants thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 187 (or variants thereof); (xx) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 192 (or variants thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 197 (or variants thereof); (xxi) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 202 (or variants thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 207 (or variants thereof); (xxii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 212 (or variants thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 217 (or variants thereof); (xxiii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 222 (or variants thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: (xxiv) a LCVR having the amino acid sequence set forth in SEQ ID NO: 232 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 237 (or a variant thereof); (xxv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 242 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 247 (or a variant thereof);(xxvi) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 252 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 257 (or a variant thereof); (xxvii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 262 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 267 (or a variant thereof); (xxviii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 272 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 277 (or a variant thereof); (xxix) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 282 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 287 (or a variant thereof); (xxx) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 292 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 297 (or a variant thereof); (xxxi) a HCVR having an amino acid sequence as set forth in SEQ ID NO: NO: 302 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 307 or 527 (or a variant thereof); and / or (xxxii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 312 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 317 (or a variant thereof).

[0018] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: i. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 329 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 328 (or a variant thereof); ii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 331 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 330 (or a variant thereof); iii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 333 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 332 (or a variant thereof); iv. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 335 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 334 (or a variant thereof); v. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 337 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: NO: 336 (or variants thereof); vi. a heavy chain region having an amino acid sequence set forth in SEQ ID NO: 339 (or variants thereof); and a light chain having an amino acid sequence set forth in SEQ ID NO: 338 (or variants thereof); vii. a heavy chain region having an amino acid sequence set forth in SEQ ID NO: 341 (or variants thereof); and a light chain having an amino acid sequence set forth in SEQ ID NO: 340 (or variants thereof); viii. a heavy chain region having an amino acid sequence set forth in SEQ ID NO: 343 (or variants thereof); and a light chain having an amino acid sequence set forth in SEQ ID NO: 342 (or variants thereof); ix. a heavy chain region having an amino acid sequence set forth in SEQ ID NO: 345 (or variants thereof); and a light chain having an amino acid sequence set forth in SEQ ID NO: 344 (or variants thereof); x. a heavy chain region having an amino acid sequence set forth in SEQ ID NO: 347 (or variants thereof); and a light chain having an amino acid sequence set forth in SEQ ID NO: 348 (or variants thereof); NO: 346 (or a variant thereof); xi. a heavy chain region having the amino acid sequence set forth in SEQ ID NO: 349 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 348 (or a variant thereof); xii. a heavy chain region having the amino acid sequence set forth in SEQ ID NO: 351 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 350 (or a variant thereof); xiii. a heavy chain region having the amino acid sequence set forth in SEQ ID NO: 353 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 352 (or a variant thereof); xiv.a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 355 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 354 (or a variant thereof); xv. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 357 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 356 (or a variant thereof); xvi. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 359 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 358 (or a variant thereof); xvii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 361 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 360 (or a variant thereof); xviii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 363 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 362 (or a variant thereof); xix. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 364 (or a variant thereof); NO: 365 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 364 (or a variant thereof); xx. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 367 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 366 (or a variant thereof); xxi. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 369 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 368 (or a variant thereof); xxii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 371 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 370 (or a variant thereof); xxiii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 373 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 372 (or a variant thereof); xxiv. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 374 (or a variant thereof); xxv. a heavy chain region having the amino acid sequence set forth in SEQ ID NO: 377 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 376 (or a variant thereof); xxvi. a heavy chain region having the amino acid sequence set forth in SEQ ID NO: 379 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 378 (or a variant thereof); xxvii.a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 381 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 380 (or a variant thereof); xxviii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 383 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 382 (or a variant thereof); xxix. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 385 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 384 (or a variant thereof); xxx. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 387 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 386 (or a variant thereof); xxxi. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 389 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 388 (or a variant thereof); or xxxii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 389 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 388 (or a variant thereof); A heavy chain region having the amino acid sequence shown in SEQ ID NO: 391 (or a variant thereof); and a light chain region having the amino acid sequence shown in SEQ ID NO: 390 (or a variant thereof).

[0019] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: i. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 543 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 328 (or a variant thereof); ii. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 544 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 330 (or a variant thereof); iii. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 545 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 332 (or a variant thereof); iv. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 546 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 334 (or a variant thereof); v. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 547 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 336 (or a variant thereof); vi. : the heavy chain having the amino acid sequence set forth in SEQ ID NO: 548 (or a variant thereof); and the light chain having the amino acid sequence set forth in SEQ ID NO: 338 (or a variant thereof); vii. a heavy chain having the amino acid sequence set forth in SEQ ID NO: 549 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 340 (or a variant thereof); viii. a heavy chain having the amino acid sequence set forth in SEQ ID NO: 550 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 342 (or a variant thereof); ix. a heavy chain having the amino acid sequence set forth in SEQ ID NO: 551 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 344 (or a variant thereof); x. a heavy chain having the amino acid sequence set forth in SEQ ID NO: 552 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 346 (or a variant thereof); xi. a heavy chain having the amino acid sequence set forth in SEQ ID NO: 557 (or a variant thereof); NO: 553 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 348 (or a variant thereof); xii. a heavy chain having the amino acid sequence shown in SEQ ID NO: 554 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 350 (or a variant thereof); xiii. a heavy chain having the amino acid sequence shown in SEQ ID NO: 555 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 352 (or a variant thereof); xiv.a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 556 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 354 (or a variant thereof); xv. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 557 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 356 (or a variant thereof); xvi. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 558 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 358 (or a variant thereof); xvii. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 559 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 360 (or a variant thereof); xviii. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 560 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 362 (or a variant thereof); xix. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 561 (or a variant thereof); NO: 561 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 364 (or a variant thereof); xx. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 562 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 366 (or a variant thereof); xxi. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 563 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 368 (or a variant thereof); xxii. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 564 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 370 (or a variant thereof); xxiii. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 565 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 372 (or a variant thereof); xxiv. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 566 (or a variant thereof); XXV. A heavy chain having the amino acid sequence set forth in SEQ ID NO: 567 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 376 (or a variant thereof); XXVI. A heavy chain having the amino acid sequence set forth in SEQ ID NO: 568 (or a variant thereof); and a light chain having the amino acid sequence set forth in SEQ ID NO: 378 (or a variant thereof); XXVII.a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 569 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 380 (or a variant thereof); xxviii. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 570 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 382 (or a variant thereof); xxix. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 571 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 384 (or a variant thereof); xxx. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 572 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 386 (or a variant thereof); xxxi. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 573 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 388 (or a variant thereof); or xxxii. a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 574 (or a variant thereof); A heavy chain having the amino acid sequence shown in SEQ ID NO: 574 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 390 (or a variant thereof).

[0020] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: (1) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 132 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 137 (or a variant thereof); (2) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 172 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 177 (or a variant thereof); (3) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 222 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence as set forth in SEQ ID NO: NO: 227 (or a variant thereof); (4) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 242 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 247 (or a variant thereof); (5) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 262 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 267 (or a variant thereof); or (6) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 272 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 277 (or a variant thereof).

[0021] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: (a) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 133 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 134 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 135 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 138 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 139 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 140 (or a variant thereof); (b) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 173 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 174 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: NO: 175 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 178 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 179 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 180 (or a variant thereof); (c) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 223 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 224 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 225 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence as set forth in SEQ ID NO: 228 (or a variant thereof), a LCDR2 having an amino acid sequence as set forth in SEQ ID NO: 229 (or a variant thereof), and a LCDR3 having an amino acid sequence as set forth in SEQ ID NO: 180 (or a variant thereof). (d) a HCVR comprising: a HCDR1 having an amino acid sequence as set forth in SEQ ID NO: 243 (or a variant thereof), a HCDR2 having an amino acid sequence as set forth in SEQ ID NO: 244 (or a variant thereof), and a HCDR3 having an amino acid sequence as set forth in SEQ ID NO: 245 (or a variant thereof);and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 248 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 249 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 250 (or a variant thereof); (e) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 263 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 264 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 265 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 268 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 269 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 270 (or a variant thereof); or (ab) a HCVR comprising: a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 271 (or a variant thereof), a HCDR2 having an amino acid sequence set forth in SEQ ID NO: 272 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 273 (or a variant thereof). 273 (or a variant thereof), a HCDR1 having an amino acid sequence set forth in SEQ ID NO: 274 (or a variant thereof), and a HCDR3 having an amino acid sequence set forth in SEQ ID NO: 275 (or a variant thereof); and a LCVR comprising: a LCDR1 having an amino acid sequence set forth in SEQ ID NO: 278 (or a variant thereof), a LCDR2 having an amino acid sequence set forth in SEQ ID NO: 279 (or a variant thereof), and a LCDR3 having an amino acid sequence set forth in SEQ ID NO: 280 (or a variant thereof);

[0022] In some embodiments, the protein-drug conjugate comprises: (i) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 132 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 137 (or a variant thereof); (ii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 172 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 177 (or a variant thereof); (iii) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 222 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 227 (or a variant thereof); (iv) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 242 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: 247 (or a variant thereof); (v) a HCVR having an amino acid sequence as set forth in SEQ ID NO: 262 (or a variant thereof); and a LCVR having an amino acid sequence as set forth in SEQ ID NO: or (vi) a LCVR having the amino acid sequence set forth in SEQ ID NO: 267 (or a variant thereof); or (vii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 272 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 277 (or a variant thereof).

[0023] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: (A) a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 355 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 354 (or a variant thereof); (B) a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 363 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 362 (or a variant thereof); (C) a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 373 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 372 (or a variant thereof); (D) a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 377 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 376 (or a variant thereof); (E) a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 381 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: NO: 380 (or a variant thereof); or (F) a heavy chain region having the amino acid sequence shown in SEQ ID NO: 383 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 382 (or a variant thereof).

[0024] In some embodiments, the antigen binding protein of the protein-drug conjugate comprises: (I) a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 556 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 354 (or a variant thereof); (II) a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 560 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 362 (or a variant thereof); (III) a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 565 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 372 (or a variant thereof); (IV) a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 367 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: 376 (or a variant thereof); (V) a heavy chain having an amino acid sequence as set forth in SEQ ID NO: 569 (or a variant thereof); and a light chain having an amino acid sequence as set forth in SEQ ID NO: NO: 380 (or a variant thereof); or (VI) a heavy chain having the amino acid sequence shown in SEQ ID NO: 570 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 382 (or a variant thereof).

[0025] In some embodiments, the antigen binding protein binds to the same epitope on human transferrin receptor as an antibody comprising the HCVR / LCVR amino acid sequence pair shown in Table 1-1.

[0026] In some embodiments, the antigen binding protein competes for binding to human transferrin receptor with an antibody comprising the HCVR / LCVR amino acid sequence pair shown in Table 1-1.

[0027] In another aspect, provided herein is a protein-drug conjugate comprising an antigen binding protein that specifically binds to human transferrin receptor (hTfR), wherein the antigen binding protein is conjugated to a molecular cargo and comprises an antibody or antigen binding fragment thereof, wherein the antibody or antigen binding fragment thereof binds to one or more hTfR epitopes selected from:

[0028] a. an epitope having the sequence LLNE (SEQ ID NO: 529) and / or an epitope having the sequence TYKEL (SEQ ID NO: 509);

[0029] b. an epitope having the sequence DSTDFTGT (SEQ ID NO: 530) and / or an epitope having the sequence VKHPVTGQF (SEQ ID NO: 531) and / or an epitope having the sequence IERIPEL (SEQ ID NO: 532);

[0030] c. an epitope having the sequence LNENSYVPREAGSQKDEN (SEQ ID NO: 533);

[0031] d. an epitope having the sequence FEDL (SEQ ID NO: 521);

[0032] e. an epitope having the sequence IVDKNGRL (SEQ ID NO: 534);

[0033] f. an epitope having the sequence IVDKNGRLVY (SEQ ID NO: 535);

[0034] g. an epitope having the sequence DQTKF (SEQ ID NO: 536);

[0035] h. an epitope having the sequence LVENPGGY (SEQ ID NO: 537) and / or an epitope having the sequence PIVNAELSF (SEQ ID NO: 538) and / or an epitope having the sequence PYLGTTMDT (SEQ ID NO: 539);

[0036] i. an epitope having the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope having the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope having the sequence TYKEL (SEQ ID NO: 509);

[0037] j. an epitope having the sequence KRKLSEKLDSTDFTGTIKL (SEQ ID NO: 510) and / or an epitope having the sequence YTLIEKTMQNVKHPVTGQFL (SEQ ID NO: 511) and / or an epitope having the sequence LIERIPELNKVARAAAE (SEQ ID NO: 512);

[0038] k. an epitope having the sequence LNENSYVPREAGSQKDENL (SEQ ID NO: 513); l. an epitope having the sequence GTKKDFEDL (SEQ ID NO: 514);

[0039] m. an epitope having the sequence SVIIVDKNGRLVYLVENPGGYVAYSK (SEQ ID NO: 515);

[0040] n. an epitope having the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope having the sequence DQTKFPIVNAEL (SEQ ID NO: 517) and / or an epitope having the sequence TYKELIERIPELNK (SEQ ID NO: 518);

[0041] o. an epitope having the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope having the sequence TYKELIERIPELNK (SEQ ID NO: 518);

[0042] p. an epitope having the sequence SVIIVDKNGRLVYLVENPGGYVAY (SEQ ID NO: 519);

[0043] q. an epitope having the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope having the sequence FGNMEGDCPSDWKTDSTCRM (SEQ ID NO: 520);

[0044] r. an epitope having the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope having the sequence LVENPGGYVAYSKAATVTGKL (SEQ ID NO: 522) and / or an epitope having the sequence IYMDQTKFPIVNAELSF (SEQ ID NO: 523) and / or an epitope having the sequence ISRAAAEKL (SEQ ID NO: 524) and / or an epitope having the sequence VTSESKNVKLTVSNVLKE (SEQ ID NO: 525) and / or an epitope having the sequence FCEDTDYPYLGTTMDT (SEQ ID NO: 526);

[0045] s. an epitope contained within or overlapping with the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope contained within or overlapping with the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope contained within or overlapping with the sequence TYKEL (SEQ ID NO: 509);

[0046] t. an epitope contained within or overlapping with the sequence KRKLSEKLDSTDFTGTIKL (SEQ ID NO: 510) and / or an epitope contained within or overlapping with the sequence YTLIEKTMQNVKHPVTGQFL (SEQ ID NO: 511) and / or an epitope contained within or overlapping with the sequence LIERIPELNKVARAAAE (SEQ ID NO: 512);

[0047] u. an epitope contained within or overlapping the sequence LNENSYVPREAGSQKDENL (SEQ ID NO: 513);

[0048] v. an epitope contained within or overlapping with the sequence GTKKDFEDL (SEQ ID NO: 514);

[0049] w. an epitope contained within or overlapping with the sequence SVIIVDKNGRLVYLVENPGGYVAYSK (SEQ ID NO: 515);

[0050] x. an epitope contained within or overlapping with the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope contained within or overlapping with the sequence DQTKFPIVNAEL (SEQ ID NO: 517) and / or an epitope contained within or overlapping with the sequence TYKELIERIPELNK (SEQ ID NO: 518);

[0051] y. an epitope contained within or overlapping the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope contained within or overlapping the sequence TYKELIERIPELNK (SEQ ID NO: 518);

[0052] z. an epitope contained within or overlapping with the sequence SVIIVDKNGRLVYLVENPGGYVAY (SEQ ID NO: 519);

[0053] aa. an epitope contained within or overlapping with the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope contained within or overlapping with the sequence FGNMEGDCPSDWKTDSTCRM (SEQ ID NO: 520); and

[0054] bb. an epitope contained within or overlapping with the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO:507) and / or an epitope contained within or overlapping with the sequence LVENPGGYVAYSKAATVTGKL (SEQ ID NO:522) and / or an epitope contained within or overlapping with the sequence IYMDQTKFPIVNAELSF (SEQ ID NO:523) and / or an epitope contained within or overlapping with the sequence ISRAAAEKL (SEQ ID NO:524) and / or an epitope contained within or overlapping with the sequence VTSESKNVKLTVSNVLKE (SEQ ID NO:525) and / or an epitope contained within or overlapping with the sequence FCEDTDYPYLGTTMDT (SEQ ID NO:526).

[0055] In some embodiments, the antibody or antigen-binding fragment thereof binds to one or more hTfR epitopes selected from:

[0056] a. an epitope consisting of the sequence LLNE (SEQ ID NO: 529) and / or an epitope consisting of the sequence TYKEL (SEQ ID NO: 509);

[0057] b. an epitope consisting of the sequence DSTDFTGT (SEQ ID NO: 530) and / or an epitope consisting of the sequence VKHPVTGQF (SEQ ID NO: 531) and / or an epitope consisting of the sequence IERIPEL (SEQ ID NO: 532);

[0058] c. an epitope consisting of the sequence LNENSYVPREAGSQKDEN (SEQ ID NO: 533);

[0059] d. an epitope consisting of the sequence FEDL (SEQ ID NO: 521);

[0060] e. an epitope consisting of the sequence IVDKNGRL (SEQ ID NO: 534);

[0061] f. an epitope consisting of the sequence IVDKNGRLVY (SEQ ID NO: 535);

[0062] g. an epitope consisting of the sequence DQTKF (SEQ ID NO: 536);

[0063] h. an epitope consisting of the sequence LVENPGGY (SEQ ID NO: 537) and / or an epitope consisting of the sequence PIVNAELSF (SEQ ID NO: 538) and / or an epitope consisting of the sequence PYLGTTMDT (SEQ ID NO: 539);

[0064] i. an epitope consisting of the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope consisting of the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope consisting of the sequence TYKEL (SEQ ID NO: 509);

[0065] j. an epitope consisting of the sequence KRKLSEKLDSTDFTGTIKL (SEQ ID NO: 510) and / or an epitope consisting of the sequence YTLIEKTMQNVKHPVTGQFL (SEQ ID NO: 511) and / or an epitope consisting of the sequence LIERIPELNKVARAAAE (SEQ ID NO: 512);

[0066] k. an epitope consisting of the sequence LNENSYVPREAGSQKDENL (SEQ ID NO: 513);

[0067] 1. an epitope consisting of the sequence GTKKDFEDL (SEQ ID NO: 514);

[0068] m. an epitope consisting of the sequence SVIIVDKNGRLVYLVENPGGYVAYSK (SEQ ID NO: 515);

[0069] n. an epitope consisting of the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope consisting of the sequence DQTKFPIVNAEL (SEQ ID NO: 517) and / or an epitope consisting of the sequence TYKELIERIPELNK (SEQ ID NO: 518);

[0070] o. an epitope consisting of the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope consisting of the sequence TYKELIERIPELNK (SEQ ID NO: 518);

[0071] p. an epitope consisting of the sequence SVIIVDKNGRLVYLVENPGGYVAY (SEQ ID NO: 519);

[0072] q. an epitope consisting of the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope consisting of the sequence FGNMEGDCPSDWKTDSTCRM (SEQ ID NO: 520); and

[0073] r. An epitope consisting of the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope consisting of the sequence LVENPGGYVAYSKAATVTGKL (SEQ ID NO: 522) and / or an epitope consisting of the sequence IYMDQTKFPIVNAELSF (SEQ ID NO: 523) and / or an epitope consisting of the sequence ISRAAAEKL (SEQ ID NO: 524) and / or an epitope consisting of the sequence VTSESKNVKLTVSNVLKE (SEQ ID NO: 525) and / or an epitope consisting of the sequence FCEDTDYPYLGTTMDT (SEQ ID NO: 526).

[0074] In some embodiments, the antigen binding protein is selected from a humanized antibody or antigen binding fragment thereof, a human antibody or antigen binding fragment thereof, a murine antibody or antigen binding fragment thereof, a chimeric antibody or antigen binding fragment thereof, a monovalent Fab', a divalent Fab2, a F(ab)'3 fragment, a single-chain fragment variable region (scFv), a double scFv, (scFv)2, a double-chain antibody, a minibody, a nanobody, a three-chain antibody, a four-chain antibody, a disulfide-stabilized Fv protein (dsFv), a single domain antibody (sdAb), an IgNAR, a single heavy chain antibody, a bispecific antibody or a binding fragment thereof, a bispecific T cell engager (BiTE), a trispecific antibody, or a chemically modified derivative thereof.

[0075] In some embodiments, the protein-drug conjugate comprises an scFv comprising a heavy chain variable region (HCVR) and a light chain variable region (LCVR) and a molecular cargo, wherein the molecular cargo is conjugated to the HCVR. In some embodiments, the protein-drug conjugate comprises an scFv comprising a heavy chain variable region (HCVR) and a light chain variable region (LCVR) and a molecular cargo, wherein the molecular cargo is conjugated to the LCVR. In some embodiments, the scFv and the molecular cargo are conjugated via a linker.

[0076] In some embodiments, the molecular cargo is conjugated to: (i) the HCVR of the antigen binding protein, (ii) the LCVR of the antigen binding protein, (iii) the heavy chain of the antigen binding protein, and / or (iv) the light chain of the antigen binding protein.

[0077] In some embodiments, the molecular cargo is conjugated to: (i) one or both HCVRs of an antigen binding protein, (ii) one or both LCVRs of an antigen binding protein, (iii) one or both heavy chains of an antigen binding protein, and / or (iv) one or both light chains of an antigen binding protein.

[0078] In some embodiments, the molecular cargo is conjugated to the antigen binding protein via glutamine residues and / or lysine residues.

[0079] In some embodiments, the glutamine residue: (i) is introduced into the N-terminus and / or C-terminus of the heavy chain of the antigen binding protein, (ii) is introduced into the N-terminus and / or C-terminus of the light chain of the antigen binding protein, (iii) is naturally present in the CH2 or CH3 domain of the antigen binding protein, (iv) is introduced into the antigen binding protein by modification of one or more amino acids, and / or (v) is Q295 or is mutated from N297 to Q297 (N297Q). In one embodiment, the glutamine residue is Q295.

[0080] In some embodiments, the antigen binding protein comprises a glutamine-containing tag, and the molecular cargo is conjugated to the antigen binding protein via the glutamine residue of the glutamine-containing tag. In some embodiments, the glutamine-containing tag comprises an amino acid sequence selected from the group consisting of LLQGG (SEQ ID NO: 439), LLQG (SEQ ID NO: 440), LSLSQG (SEQ ID NO: 441), gGGLLQGG (SEQ ID NO: 442), gLLQG (SEQ ID NO: 443), LLQ (SEQ ID NO: 444), gSPLAQSHGG (SEQ ID NO: 445), gLLQGGG (SEQ ID NO: 446), gLLQGG (SEQ ID NO: 447), gLLQ (SEQ ID NO: 448), LLQLLQGA (SEQ ID NO: 449), LLQGA (SEQ ID NO: 450), LLQYQGA (SEQ ID NO: 451), LLQGSG (SEQ ID NO: 452), LLQYQG (SEQ ID NO: 453), LLQLLQG (SEQ ID NO: 454), SLLQG (SEQ ID NO: 455). NO:455), LLQLQ (SEQ ID NO:456), LLQLLQ (SEQ ID NO:457) and LLQGR (SEQ ID NO:458).

[0081] In some embodiments, the antigen binding protein and the molecular cargo are conjugated via a linker. The linker can be a cleavable or non-cleavable linker.

[0082] In some embodiments, the protein-drug conjugate comprises a molecular cargo comprising a polynucleotide molecule, a vector, or a small molecule.

[0083] In some embodiments, the protein-drug conjugate comprises a polynucleotide molecule. In some embodiments, the polynucleotide molecule is an interfering nucleic acid molecule, a guide RNA, a ribozyme, an aptamer, a hybrid, a multimer, or an mRNA. In some embodiments, the interfering nucleic acid is an siRNA, shRNA, miRNA, a gapmer, or an antisense oligonucleotide. In some embodiments, the interfering nucleic acid is an siRNA. In some embodiments, the interfering nucleic acid is an antisense oligonucleotide. In some embodiments, the polynucleotide molecule is a guide RNA. In various embodiments, the polynucleotide molecule comprises one or more modified nucleotides.

[0084] In some embodiments, the molecular cargo is an siRNA that inhibits DMPK, CNBP, dystrophin, DUX4, ApoE, MAPT, APP, HTT, SOD1, C9orf72, SNCA, LRRK2, PRNP, SLC5A1, SLC16A3, HDAC6, MMP27, MFAP5, FAM64A, BAIAP3, MYH7, TPM1, RBM20, KLHL24, MYL2, or TNNT2 genes, or mutants thereof.

[0085] In some embodiments, the siRNA comprises a sense strand of 21 nucleotides in length. In some embodiments, the siRNA comprises an antisense strand of 23 nucleotides in length. In some embodiments, the siRNA comprises two phosphorothioate bonds at the first internucleoside bond and the second internucleoside bond at the 5' end of the sense strand. In some embodiments, the siRNA comprises two phosphorothioate bonds at the first internucleoside bond and the second internucleoside bond at the 3' end and / or the 5' end of the antisense strand.

[0086] In some embodiments, the molecular cargo comprises a carrier, such as a lipid-based carrier. In some embodiments, the lipid-based carrier is a lipid nanoparticle (LNP), liposome, lipidoid, or liposome complex. In some embodiments, the lipid-based carrier is a lipid nanoparticle (LNP). In some embodiments, the lipid nanoparticle (LNP) also comprises a polynucleotide molecule and / or a polypeptide molecule.

[0087] In some embodiments, lipid nanoparticles (LNPs) comprise one or more components of a gene editing system. In some embodiments, lipid nanoparticles (LNPs) comprise (a) Cas nucleases or nucleic acids encoding Cas nucleases, and / or (b) guide RNAs or one or more DNAs encoding guide RNAs. In some embodiments, the Cas nuclease is a Cas9 protein. In some embodiments, the Cas9 protein is derived from Streptococcus pyogenes Cas9 protein, Staphylococcus aureus Cas9 protein, Campylobacter jejuni Cas9 protein, Streptococcus thermophilus Cas9 protein, or Neisseria meningitidis Cas9 protein. In some embodiments, nucleic acids encoding Cas proteins are codon-optimized for expression in mammalian cells. In some embodiments, nucleic acids encoding Cas proteins are codon-optimized for expression in human cells. In some embodiments, nucleic acids encoding Cas nucleases comprise mRNA encoding Cas proteins. In some embodiments, the guide RNA is a single guide RNA (sgRNA).In some embodiments, the lipid nanoparticle (LNP) comprises a zinc finger nuclease (ZFN) or a transcription activator-like effector nuclease (TALEN).

[0088] In some embodiments, lipid nanoparticles include cationic lipids, neutral lipids, helper lipids and stealth lipids. In some embodiments, the neutral lipid is distearoylphosphatidylcholine (DSPC). In some embodiments, the helper lipid is cholesterol. In some embodiments, the stealth lipid is PEG2k-DMG.

[0089] In some embodiments, the antigen binding protein, when not conjugated to a molecular cargo, does not block more than 50% of the binding of a C-terminal fragment of the human transferrin receptor to human holo-transferrin, such binding occurring in the absence of such single-chain fragment variable region (scFv), antibody, or antigen binding fragment. In some embodiments, the blocking is measured in an enzyme-linked immunosorbent assay (ELISA) plate assay, wherein the extracellular domain of the human transferrin receptor fused to a His6-myc-myc tag is pre-bound to the scFv, antibody, or antigen binding fragment and then contacted with holo-transferrin, which is immobilized to the surface of the plate by binding to a plate-bound anti-homo-transferrin antibody.

[0090] In some embodiments, the binding of holo-transferrin and the human transferrin receptor extracellular domain is measured at a concentration of about 300 pM human transferrin receptor extracellular domain in the absence of an antigen binding protein.

[0091] In various embodiments, the protein-drug conjugates described herein have one or more of the following characteristics: a) an affinity for binding to human TfR at 25°C in surface plasmon resonance format (K D ) with an affinity of about 41 nM or higher; b) binding affinity to monkey TfR at 25°C and in surface plasmon resonance format (K D ) with an affinity of about 0 nM (no detectable binding) or higher; c) at 25°C and in surface plasmon resonance format [K for binding to monkey TfR D / K binding to human TfR d ] ratio of 0 to 278; d) when in Fab form (IgG1), it blocks about 3% to 13% of hTfR binding to human Holo-Tf; e) when in scFv (V K -V H ) form, blocks about 6% to 13% of hTfR binding to human Holo-Tf; and / or f) when it is a scFv (V H -V L ) form, blocked about 11% to 26% of hTfR binding to human Holo-Tf.

[0092] In another aspect, provided herein is a pharmaceutical composition comprising the protein-drug conjugate described herein and a pharmaceutically acceptable carrier.

[0093] In another aspect, the present invention provides a composition or kit comprising a protein-drug conjugate or a pharmaceutical composition thereof as described herein and an additional therapeutic agent. In one embodiment, the additional therapeutic agent is selected from the group consisting of alglucosidase alpha, rituximab, methotrexate, intravenous immunoglobulin (IVIG), efrucisidase alpha, salbutamol, antibiotics, cortisone, prednisone, bisphosphonates, and palivizumab. In one embodiment, the additional therapeutic agent is selected from the group consisting of beta2-adrenergic agonists, steroids, bisphosphonates, infectious disease therapeutics, vaccines, and pneumococcal vaccines.

[0094] In another aspect, provided herein is a complex comprising the protein-drug conjugate described herein and a human transferrin receptor polypeptide or an antigenic fragment thereof bound thereto.

[0095] In another aspect, the present invention provides a method for preparing a protein-drug conjugate as described herein, comprising (a) contacting an antigen-binding protein with a molecular cargo under conditions that favor conjugation of the antigen-binding protein with the molecular cargo; and (b) optionally isolating the protein-drug conjugate produced in step (a). In another aspect, the present invention provides a protein-drug conjugate that is the product of such a method.

[0096] In another aspect, provided herein is a container or injection device comprising a protein-drug conjugate described herein.

[0097] In another aspect, provided herein is a method for administering a protein-drug conjugate described herein to a subject, the method comprising introducing the protein-drug conjugate into the subject's body (e.g., brain or muscle). In some embodiments, the protein-drug conjugate is introduced into the subject's body parenterally (e.g., intravenously). In some embodiments, the protein-drug conjugate is introduced into the subject's body via intrathecal, intraventricular, or intraparenchymal injection into the central nervous system.

[0098] In another aspect, provided herein is a method for treating or preventing a disease or condition in a subject in need thereof, the method comprising administering to the subject an effective amount of a protein-drug conjugate as described herein. In some embodiments, the disease or condition is a lysosomal storage disease or condition, a cardiac disease or condition, a central nervous system (CNS) disease or condition, an eye disease or condition, a brain disease or condition, a spinal cord disease or condition, a peripheral nervous system (PNS) disease or condition, a muscle disease or condition, a cartilage disease or condition, a bone growth plate disease or condition, a kidney disease or condition, or a blood disease or condition.

[0099] In some embodiments, the disease or condition is a neurological disease or condition. In some embodiments, the disease or condition is a lysosomal storage disease, amyloidosis, neuropathy, neurodegenerative disease, seizures, behavioral disorders, leukodystrophy, neuropsychiatric disease, traumatic brain injury, neurodevelopmental disease, neuromuscular disease, ocular disease or condition, viral or microbial infection, inflammation, ischemia, and cancer.

[0100] In some embodiments, the disease or disorder is a lysosomal storage disease.

[0101] In some embodiments, the disease or condition is a neurodegenerative disease, such as Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, Parkinson's disease, or a prion disease. In some embodiments, the molecular cargo of the protein-drug conjugate is an siRNA selected from the group consisting of siRNAs that inhibit ApoE, MAPT, APP, HTT, SOD1, C9orf72, SNCA, LRRK2, or PRNP genes, or mutants thereof.

[0102] In some embodiments, the disease or condition is a cardiac disease or condition. In some embodiments, the cardiac disease or condition is heart failure. In some embodiments, the molecular cargo of the protein-drug conjugate is an siRNA selected from the group consisting of siRNAs that inhibit SLC5A1, SLC16A3, HDAC6, MMP27, MFAP5, FAM64A, BAIAP3, MYH7, TPM1, RBM20, KLHL24, MYL2, or TNNT2 genes, or mutants thereof.

[0103] In some embodiments, the disease or condition is a muscle disease or condition. In some embodiments, the muscle disease or condition is myotonic dystrophy, Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, facioscapulohumeral muscular dystrophy type 1, or muscle atrophy. In some embodiments, the molecular cargo of the protein-drug conjugate is an siRNA selected from the group consisting of siRNAs that inhibit DMPK, CNBP, dystrophin, or DUX4 genes, or mutants thereof.

[0104] In various embodiments, the protein-drug conjugate is administered to a subject in combination with an additional therapeutic agent. In some embodiments, the additional therapeutic agent is selected from the group consisting of alglucosidase alfa, rituximab, methotrexate, intravenous immunoglobulin (IVIG), efrucisidase alfa, levosalbutamol, antibiotics, cortisone, prednisone, bisphosphonates, and palivizumab. In some embodiments, the additional therapeutic agent is selected from the group consisting of beta2-adrenergic agonists, steroids, bisphosphonates, infectious disease therapeutics, vaccines, and pneumococcal vaccines.

[0105] In another aspect, provided herein is a method for treating or preventing myotonic dystrophy, Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, or facioscapulohumeral muscular dystrophy type 1 in a subject in need thereof, the method comprising administering to the subject an effective amount of a protein-drug conjugate as described herein. In some embodiments, the molecular cargo of the protein-drug conjugate is an interfering RNA (e.g., siRNA) selected from the group consisting of interfering RNAs (e.g., siRNAs) that inhibit DMPK, CNBP, dystrophin, or DUX4 genes or mutants thereof.

[0106] In another aspect, the present disclosure provides a method for treating or preventing a neurodegenerative disease in a subject in need thereof, such as Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, Parkinson's disease, or a prion disease, the method comprising administering to the subject an effective amount of a protein-drug conjugate as described herein. In some embodiments, the molecular cargo of the protein-drug conjugate is an interfering RNA (e.g., siRNA) selected from the group consisting of interfering RNAs (e.g., siRNAs) that inhibit ApoE, MAPT, APP, HTT, SOD1, C9orf72, SNCA, LRRK2, or PRNP genes or their mutants.

[0107] In another aspect, the present disclosure provides a method for treating or preventing a cardiac disease or condition, such as heart failure, in a subject in need thereof, the method comprising administering to the subject an effective amount of a protein-drug conjugate as described herein. In some embodiments, the molecular cargo of the protein-drug conjugate is an siRNA selected from the group consisting of siRNAs that inhibit SLC5A1, SLC16A3, HDAC6, MMP27, MFAP5, FAM64A, BAIAP3, MYH7, TPM1, RBM20, KLHL24, MYL2, or TNNT2 genes or mutants thereof.

[0108] In another aspect, there is provided herein a method for delivering a molecular payload to tissue or cell type in a subject, the method including administering to the subject an antigen-binding proteins specifically bound to human transferrin receptor or its antigenic fragment or its variant and the molecular payload conjugated thereto. In some embodiments, the molecular payload comprises a polynucleotide molecule, a carrier or a small molecule. In some embodiments, the tissue is brain / spinal cord / CNS, eyes, skeletal muscle, adipose tissue, blood / bone marrow, breast, lung / bronchus, colon, uterus, esophagus, heart, kidney, liver, lymph node, ovary, pancreas, placenta, prostate, rectum, skin, peripheral blood mononuclear cell (PBMC), small intestine, spleen, stomach, testis, peripheral nervous system and / or bone / cartilage / joint. In some embodiments, cell type and the tissue associated with cell type are selected from Table 1-4 herein. In some embodiments, the method includes piercing the body of the subject with the needle of a syringe, then injecting into the body of the subject an antigen-binding proteins specifically bound to transferrin receptor or its antigenic fragment or its variant and the molecular payload conjugated thereto. In some embodiments, the subject has a muscle wasting disorder, a metabolic disease, sarcopenia, or cachexia. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Figures 1A to 1CWestern blots are shown showing that anti-human TFRC antibody clones deliver GAA to the brain of Tfrchum mice. Each lane = 1 mouse. Anti-mouse mTfR:GAA in Wt mice was used as a positive control. hum Anti-mouse mTfR:GAA in mouse was used as a negative control.

[0110] Figure 2 Western blots are shown showing that a subset of anti-hTFRC antibody clones delivered mature GAA as scfv:GAA to the brain parenchyma (delivered via HDD). Anti-mouse mTfR:GAA in Wt mice was used as a positive control. hum Anti-mouse mTfR:GAA in mouse was used as a negative control.

[0111] Figure 3 Western blots are shown showing that four selected anti-hTFRC antibody clones delivered mature GAA as scFv:GAA to the brain parenchyma (AAV8 episomal liver depot gene therapy). Anti-mouse mTfR:GAA in Wt mice was used as a positive control. hum Anti-mouse mTfR:GAA in mouse was used as a negative control.

[0112] Figure 4 Western blots showing that three selected episomal AAV8 liver depot anti-hTFRC antibody clones delivered mature GAA to Gaa - / - CNS, heart, and muscle of Tfrchum mice.

[0113] Figure 5 Three selected episomal AAV8 liver reservoir anti-hTFRC antibody clones rescued Gaa - / - Tfrc hum Glycogen storage in the CNS, heart, and muscle of mice. Wt untreated mice were positive controls, and Gaa - / - Untreated mice served as negative controls.

[0114] 6A to 6D Three selected episomal AAV8 liver reservoir anti-hTFRC antibody clones rescued Gaa - / - The thalamus of Tfrchum mice ( Figure 6A ), cerebral cortex ( Figure 6B )、Hippocampal CA1( Figure 6C ) and quadriceps ( Figure 6D ) in glycogen storage. Wt untreated mice were positive controls, and Gaa - / - Untreated mice served as negative controls.

[0115] Figure 7A We show that insertion of anti-hTFRC 12847scfv:GAA delivers mature GAA protein to the CNS and muscles of Pompe disease model mice. Figure 7B The results show that the insertion of anti-hTFRC 12847scfv:GAA rescued glycogen storage in the CNS and muscles of Pompe disease model mice. One-way ANOVA*p<0.001; **p<0.0001; ***p<0.00001. Untreated Pompe disease model mice and wild-type mice were used as controls. Mice injected with recombinant AAV8 anti-TfR:GAA free template were used as positive controls. Mice injected with recombinant AAV8 anti-TfR:GAA inserted template without LNP-g666 were used as negative controls.

[0116] Figure 8 The interaction of the Machupo mammalian arenavirus (Mammarenavirus machupoense) GP1 protein (PDB 3KAS), human ferritin (PDB 6GSR), Plasmodium vivax Sal-1 PvRBP2b protein (PDB 6D04), human HFE protein (PDB 1DE4), and human transferrin (PDB 1SUV) molecules superimposed on two TfR molecules as a symmetry unit is shown. For the Machupo mammalian arenavirus GP1 protein and human ferritin, only one copy of the symmetry unit is shown to reduce the complexity of the figure.

[0117] Figure 9 Depicted, hydrogen-deuterium exchange mass spectrometry (HDX) protection of antibodies tested in HDX-MS experiments can be assigned to five regions in TfR (PDB 1SUV).

[0118] Figure 10 Shown are regions of TfR protected by REGN17513, a representative antibody that elicits HDX protection in the TfR apical domain that overlap with binding sites for the Machupo mammalian arenavirus GP1 protein, human ferritin, and Plasmodium vivax PvRBP2b protein.

[0119] Figure 11 The region of TfR protected by REGN17510 is shown, wherein REGN17510 is a TfR with a non- Figure 11 Representative of HDX-protected antibodies shared with other TfR binding partners are shown in .

[0120] Figure 12Shown are regions of TfR protected by REGN17515, a representative HDX-protected antibody with a binding site in the TfR apical domain that shares binding with human ferritin and Plasmodium vivax Sal-1 PvRBP2b protein.

[0121] Figure 13 Shown are regions of TfR protected by REGN17514, a representative HDX-protected antibody that shares a binding site with the Plasmodium vivax Sal-1 PvRBP2b protein in the TfR protease-like domain.

[0122] Figure 14 Shown is a region of TfR protected by REGN17508, which is a representative antibody with HDX protection in the TfR protease-like domain. Figure 14 Other TfR-interacting molecules are utilized as shown. DETAILED DESCRIPTION

[0123] Provided herein are anti-transferrin receptor (TfR) antigen binding proteins conjugated to a molecular cargo. Such conjugates can be used, for example, to deliver molecular cargo to various tissues in vivo, including brain and muscle. For example, anti-TfR protein-drug conjugates are provided, which exhibit high affinity and excellent blood-brain barrier crossing to transferrin receptor. Surprisingly, the anti-TfRscFv that exhibits high binding affinity to TfR is more effective than low-affinity binding agents in crossing the blood-brain barrier. This is in contrast to the findings previously using monovalent and divalent anti-TFR antibodies, in which low-affinity antibodies more effectively crossed the blood-brain barrier. The conjugates described herein have the ability to effectively deliver molecular cargo to the brain and muscle, and therefore can be used to treat diseases and disorders, such as neurological or muscular diseases and disorders.

[0124] In light of the present disclosure, conventional molecular biology, microbiology, and recombinant DNA techniques can be employed within the skill of the art. Such techniques are fully explained in the literature. See, e.g., Sambrook, Fritsch and Maniatis, Molecular Cloning: A Laboratory Manual, 2nd ed. (1989) Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY (referred to herein as "Sambrook et al., 1989"); DNA Cloning: A Practical Approach, Vols. I and II (D. N. Glover, ed., 1985); Oligonucleotide Synthesis (M. J. Gait, ed., 1984); Nucleic Acid Hybridization (B. D. Hames and S. J. Higgins, eds., (1985)); Transcription And Translation (B. D. Hames and S. J. Higgins, eds., (1984)); Animal Cell Culture (R. I. Freshney, ed., (1986)); Immobilized Cells And Enzymes (IRL Press, (1986)); B. Perbal, A Practical Guide ToMolecularCloning (1984); FM Ausubel et al., (eds.), Current Protocols in Molecular Biology, John Wiley & Sons, Inc. (1994).

[0125] Polynucleotides include DNA and RNA.The present disclosure includes any polynucleotide described herein operably linked to a promoter or other expression control sequence.

[0126] Transferrin receptor 1 (TfR) is a membrane receptor that participates in controlling the iron supply to cells by the binding of transferrin (the main iron carrier protein). Transferrin receptor 1 is expressed by the TFRC gene. Transferrin receptor 1 may be referred to as TFRC herein. This receptor plays a key role in the control of cell proliferation because iron is necessary to maintain ribonucleotide reductase activity and is the only enzyme that catalyzes the conversion of ribonucleotides into deoxyribonucleotides. Preferably, TfR is human TfR (hTfR). See, for example, accession numbers NP_001121620.1; BAD92491.1 and NP_001300894.1; and e! Ensembl entry: ENSG00000072274. Human transferrin receptor 1 is expressed in several tissues, including but not limited to: cerebral cortex; cerebellum; hippocampus; caudate nucleus; parathyroid glands; adrenal glands; bronchi; lungs; oral mucosa; esophagus; stomach; duodenum; small intestine; colon; rectum; liver; gallbladder; pancreas; kidney; bladder; testis; epididymis; prostate; vagina; ovary; fallopian tube; endometrium; cervix; placenta; breast; myocardium; smooth muscle; soft tissue; skin; appendix; lymph nodes; tonsils; and bone marrow. See also Tables 1-4 of this document for the tissue and cell types. A related transferrin receptor is transferrin receptor 2 (TfR2). Human transferrin receptor 2 has approximately 45% sequence identity to human transferrin receptor 1. "Trinder & Baker, Transferrin receptor 2: a new molecule iniron metabolism." Int J Biochem Cell Biol. 2003 Mar; 35(3): 292-6. Unless otherwise indicated, transferrin receptor as used herein generally refers to transferrin receptor 1 (eg, human transferrin receptor 1).

[0127] Human transferrin (Tf) is the single-chain 80kDa member of anion-binding protein superfamily.Transferrin is 698 amino acid whose precursor, which is divided into 19 amino acid whose signal sequences add 679 amino acid whose mature segments usually contain 19 intrachain disulfide bonds.N-terminal and C-terminal side joint district (or structural domain) are by the interaction binding ferric iron of obligate anion (for example, bicarbonate) and four amino acid (His, Asp and two Tyr).Apoferronic (or iron-free) transferrin will initially be by in conjunction with an iron atom at C-terminal, then carry out by the follow-up iron of N-terminal and combine to form holotransferrin (two iron Tf, Holo-Tf).Hollow transferrin will interact with the TfR on cell surface by the iron binding domain of its C-terminal, and at cell surface, it is internalized in the endosome of acidification.Iron dissociates from the Tf molecule in these endosomes, and is transported in cytosol as ferrous iron. In addition to TfR, transferrin has also been reported to bind to cubulin, IGFBP3, microbial iron-binding protein, and liver-specific TfR2.

[0128] The blood-brain barrier (BBB) ​​is located within the brain's microvasculature and regulates the passage of molecules from the blood into the brain. Burkhart et al., Accessing targeted nanoparticles to the brain: the vascular route. Curr Med Chem. 2014; 21(36): 4092-9. Transcellular transport through brain capillary endothelial cells can occur via the following pathways: 1) leukocyte entry into the cell; 2) carrier-mediated inward transport, for example, glucose transporter 1 (GLUT-1) inward transport of glucose, for example, L-type amino acid transporter 1 (LAT-1) inward transport of amino acids, and for example, organic anion transporting peptide B (OATP-B) inward transport of small peptides; 3) paracellular passage of small hydrophobic molecules; 4) adsorption-mediated transcytosis, for example, transcytosis of albumin and cationized molecules; 5) passive diffusion of lipid-soluble non-polar solutes (including CO2 and O2); and 5) receptor-mediated transcytosis, for example, transcytosis of insulin by the insulin receptor and transcytosis of TfR by Tf. Johnsen et al., Targeting the transferrin receptor for brain drug delivery, Prog Neurobiol. 2019 Oct; 181: 101665.

[0129] Anti-human transferrin receptor antigen binding protein conjugate

[0130] Provided herein are anti-hTfR protein-drug conjugates. The anti-hTfR protein-drug conjugates comprise an optional signal peptide connected to an antigen binding protein (e.g., an antibody or an antigen binding fragment of an antibody, such as Fab or scFv) that specifically binds to a transferrin receptor, preferably human transferrin receptor 1 (hTfR), the antigen binding protein (optionally through a linker) being conjugated to a molecular cargo. The anti-hTfR antigen binding proteins described herein effectively cross the blood-brain barrier (BBB), thereby enabling the conjugated molecular cargo to be delivered to the brain.

[0131] Antigen binding proteins that specifically bind to transferrin receptor and protein-drug conjugates thereof (e.g., human transferrin receptor (e.g., REGN2431) or monkey transferrin receptor (e.g., REGN2054)), e.g., tags such as His6 and / or myc, with a K of about 20 nM at about 25° C., e.g., in a surface plasmon resonance assay. d Such antigen binding proteins can be referred to as "anti-TfR".

[0132] The term "conjugate" means a subject in which two substances are covalently or non-covalently connected. The term "covalently connected" refers to the feature that at least two molecules are connected together by one or more covalent bonds. In various embodiments, two molecules can be covalently linked together by a single bond (for example, a disulfide bridge or a disulfide bond) acting as a joint between molecules. In some embodiments, two or more molecules can be covalently linked together by a molecule acting as a joint, and this joint joins at least two molecules together via multiple covalent bonds. In certain embodiments, the joint can be a cleavable joint or a non-cleavable joint. In a conjugate, two substances can be directly connected or can be connected via a joint. In certain embodiments, a substance in the two substances is an antigen binding protein, such as an antibody or its antigen-binding fragment, and another is a drug (for example, polynucleotides disclosed herein or liposomes or LNP). In certain embodiments, the joint can be a cleavable joint or can be a non-cleavable joint.

[0133] As used herein, the term "antibody-drug conjugate" or "ADC" refers to a conjugate of an antibody or antigen-binding fragment thereof and a drug (e.g., a polynucleotide disclosed herein, or a liposome or LNP). By linking the antibody or antigen-binding fragment thereof to the drug (e.g., a polynucleotide disclosed herein, or a liposome or LNP), the drug is given affinity for the antigen, thereby improving the efficiency of drug delivery to the target site in the body.

[0134] In one embodiment, amino acids are assigned to each framework or CDR domain in an immunoglobulin according to the definitions in Sequences of Proteins of Immunological Interest, Kabat et al.; National Institutes of Health, Bethesda, Md., 5th edition, NIH publication number 91-3242 (1991); Kabat (1978) Adv. Prot. Chem. 32: 1-75; Kabat et al., (1977) J. Biol. Chem. 252: 6609-6616; Chothia et al., (1987) J Mol. Biol. 196: 901-917; or Chothia et al., (1989) Nature 342: 878-883. Thus, also included herein are antibodies and antigen-binding fragments comprising V H CDR and V L CDR, the V H and V L comprising an amino acid sequence as set forth herein (see, e.g., the sequences of Table 1-1, or variants thereof), wherein the CDRs are as defined according to Kabat and / or Chothia.

[0135] The protein-drug conjugates described herein comprise an antibody that specifically binds to human transferrin receptor 1. As used herein, the term "antibody" refers to an immunoglobulin molecule comprising four polypeptide chains interconnected by disulfide bonds, namely two heavy chains (HC) and two light chains (LC). In one embodiment, each antibody heavy chain (HC) comprises a heavy chain variable region ("HCVR" or "V H , 462, 12, 463, 22, 464, 32, 42, 52, 467, 62, 492, 72, 470, 82, 92, 472, 102, 112, 473, 122, 132, 142, 475, 152, 162, 477, 172, 182, 478, 192, 480, 202, 481, 212, 222, 232, 242, 252, 482, 262, 272, 282, 292, 302, 483 and / or 312, or a variant thereof) and a heavy chain constant region (e.g., human IgG, human IgG1 or human IgG4); and each antibody light chain (LC) comprises a light chain variable region ("LCVR" or "VVR"). L7, 465, 47, 466, 57, 468, 67, 469, 77, 471, 87, 97, 107, 117, 474, 127, 137, 147, 476, 157, 167, 177, 187, 479, 197, 207, 217, 227, 237, 247, 257, 267, 277, 287, 297, 307, 527, 317 and / or 484, or a variant thereof) and a light chain constant region (e.g., human kappa or human lambda). V H Area and V L The V region can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDRs), interspersed with regions that are more conserved, termed framework regions (FRs). H and V L It comprises three CDRs and four FRs. The anti-TfR antibodies described herein can also be conjugated to a molecular cargo.

[0136] The anti-TfR antigen binding proteins described herein can be antigen binding fragments of antibodies that can be conjugated to molecular cargoes. As used herein, the term "antigen binding portion" or "antigen binding fragment" of an antibody refers to an immunoglobulin molecule that binds to an antigen but does not contain all sequences of a complete antibody (preferably, a complete antibody is IgG). Non-limiting examples of antigen binding fragments include: (i) Fab fragments; (ii) F(ab')2 fragments; (iii) Fd fragments; (iv) Fv fragments; (v) single-chain Fv (scFv) molecules; and (vi) dAb fragments; composed of amino acid residues (e.g., isolated complementary determining regions (CDRs), such as CDR3 peptides) or constrained FR3-CDR3-FR4 peptides of the hypervariable regions of simulated antibodies. Other engineered molecules such as domain-specific antibodies, single-domain antibodies, one-arm antibodies, domain-deleted antibodies, chimeric antibodies, CDR-grafted antibodies, double-chain antibodies, three-chain antibodies, four-chain antibodies, mini antibodies, and small modular immune drugs (SMIPs) are also encompassed within the expression "antigen binding fragment" as used herein.

[0137] In some embodiments, the anti-TfR protein-drug conjugates described herein may comprise a scFv conjugated to a molecular cargo. scFv (single chain fragment variable region) has a heavy chain (V H ) domain and light chain (V L ) domains (in either order), which are preferably joined together by a flexible linker (e.g., a peptide linker). The length of the flexible linker used to connect the two V regions may be important for producing the correct folding of the polypeptide chain. It has been previously estimated that the peptide linker must span 3.5 nm between the carboxyl terminus of the variable domain and the amino terminus of the other domain. Without affecting the ability of these domains to fold and form a complete antigen binding site (Huston et al., Protein engineering of single-chain Fv analogs and fusion proteins. Methods in Enzymology. 1991; 203: 46-88). In one embodiment, the linker comprises an amino acid sequence of such length to separate the variable domains by about 3.5 nm. In one embodiment of the invention, the anti-TfR scFv-drug conjugate comprises an scFv comprising the following variable region arrangement: LCVR-HCVR or HCVR-LCVR, wherein the HCVR and LCVR are optionally connected by a linker and the scFv is optionally connected to a molecular cargo (e.g., LCVR-(Gly4Ser)3-HCVR-molecular cargo; or LCVR-((Gly4Ser)3-HCVR-molecular cargo) via a linker.

[0138] In some embodiments, the anti-TfR protein-drug conjugates described herein may comprise a Fab conjugated to a molecular cargo.

[0139] In some embodiments, the anti-TfR protein-drug conjugates described herein comprise a bivalent antibody conjugated to a molecular cargo.

[0140] In some embodiments, the anti-TfR protein-drug conjugates described herein comprise a monovalent or "one-armed" antibody conjugated to a molecular payload. As used herein, a monovalent or "one-armed" antibody refers to an immunoglobulin comprising a single variable domain. For example, the one-armed antibody may comprise a single variable domain within a Fab, wherein the Fab is connected to at least one Fc fragment. In certain embodiments, the one-armed antibody comprises: (i) a heavy chain containing a heavy chain constant region and a heavy chain variable region, (ii) a light chain containing a light chain constant region and a light chain variable region, and (iii) a polypeptide containing an Fc fragment or a truncated heavy chain. In certain embodiments, the Fc fragment or truncated heavy chain contained in a separate polypeptide is a "virtual Fc", which refers to an Fc fragment that is not connected to an antigen binding domain. The one-armed antibodies described herein may have any HCVR / LCVR pair or CDR amino acid sequence shown herein in Table 1-1. Standard methods can be used to construct a one-armed antibody comprising a full-length heavy chain, a full-length light chain, and an additional Fc domain polypeptide (see, for example, WO2010151792, which is incorporated herein by reference in its entirety), wherein the heavy chain constant region differs from the Fc domain polypeptide by at least two amino acids (e.g., H95R and Y96F according to the IMGT exon numbering system; or H435R and Y436F according to the EU numbering system). Such modifications can be used to purify the monovalent antibody (see WO2010151792).

[0141] In one embodiment, the antigen-binding fragment of an antibody will comprise at least one variable domain. The variable domain can be of any size or amino acid composition and generally comprises at least one CDR that is adjacent to or in frame with one or more framework sequences. H domain and its associated V L In the antigen-binding fragment of the structural domain, V H domain and V L The domains can be positioned relative to each other in any suitable arrangement. For example, the variable region can be dimeric and contain V H -V H 、V H -V L or V L -V L Alternatively, the antigen-binding fragment of an antibody may contain a monomer V H or V L domain.

[0142] In certain embodiments, the antigen-binding fragment of an antibody may contain at least one variable domain covalently linked to at least one constant domain. Non-limiting exemplary configurations of variable and constant domains that may be found within the antigen-binding fragments of an antibody described herein include: (i) V H -CH1, (ii)V H -CH2, (iii) VH-CH3, (iv) V H -CH1-CH2, (v)V H -CH1-CH2-CH3, (vi)VH-CH2-CH3, (vii)V H -CL, (viii)VL-CH1, (ix)VL-CH2, (x)VL-CH3, (xi)VL-CH1-CH2, (xii)VL-CH1-CH2-CH3, (xiii)V L -CH2-CH3 and (xiv)V L-CL. In any configuration of variable domains and constant domains (including any of the exemplary configurations listed above), the variable domains and constant domains may be directly connected to each other, or may be connected by a complete or partial hinge region or linker region. The hinge region may be composed of at least 2 (e.g., 5, 10, 15, 20, 40, 60 or more) amino acids, which form a flexible or semi-flexible linker between adjacent variable domains and / or constant domains in a single polypeptide molecule. In addition, the antigen-binding fragments of the antibodies described herein may include homodimers or heterodimers (or other multimers) having any of the variable domains and constant domain configurations listed above, which are non-covalently associated with each other and / or with one or more monomers V H or V L The domains are non-covalently associated (eg, through disulfide bonds).The present disclosure includes antigen-binding fragments of antigen-binding proteins, such as the antibodies set forth herein.

[0143] Antigen binding proteins (e.g., antibodies and antigen binding fragments) can be monospecific or multispecific (e.g., bispecific). Multispecific antigen binding proteins are further discussed herein. The present disclosure includes monospecific as well as multispecific (e.g., bispecific) antigen binding fragments comprising one or more variable domains from the antigen binding proteins specifically described herein.

[0144] The term "specifically binds" refers to a specific binding affinity for an antigen (such as human TfR protein, mouse TfR protein or monkey TfR protein). D Those antigen binding proteins (e.g., antibodies or antigen binding fragments thereof) that exhibit a binding affinity of at least about 10-9 M (e.g., 0.01 nM, 0.1 nM, 0.2 nM, 0.3 nM, 0.4 nM, 0.5 nM, 0.6 nM, 0.7 nM, 0.8 nM, 0.9 nM, or 1.0 nM) as measured by real-time, label-free biolayer interferometry assays, e.g., at 25° C. or 37° C. (e.g., HTX biosensors), or by surface plasmon resonance (e.g., BIACORE TM ), or as measured by solution affinity ELISA. The present disclosure includes antigen binding proteins that specifically bind to TfR proteins. "Anti-TfR" refers to an antigen binding protein (or other molecule) that specifically binds to TfR, for example, an antibody or an antigen binding fragment thereof.

[0145] "Isolated" antigen-binding proteins (e.g., antibodies or antigen-binding fragments thereof), polypeptides, polynucleotides, and vectors are at least partially free of other biomolecules from the cells or cell cultures in which they are produced. Such biomolecules include nucleic acids, proteins, other antibodies or antigen-binding fragments, lipids, carbohydrates, or other materials such as cell debris and growth medium. An isolated antigen-binding protein may also be at least partially free of expression system components, such as biomolecules from the host cell or its growth medium. Generally, the term "isolated" is not intended to refer to the complete absence of such biomolecules (e.g., a small or insignificant amount of impurities may remain), or to the absence of water, buffers, or salts, or to components of a pharmaceutical formulation comprising the antigen-binding protein (e.g., antibody or antigen-binding fragment).

[0146] The present disclosure includes antigen binding proteins, eg, antibodies or antigen binding fragments, that bind to the same epitope as the antigen binding proteins described herein.

[0147] An antigen is a molecule, such as a peptide (e.g., TfR or a fragment thereof (antigenic fragment)) to which an antibody or antigen-binding fragment thereof binds. The specific region on an antigen that an antibody recognizes and binds to is called an epitope. Antigen binding proteins (e.g., antibodies) described herein that specifically bind to such antigens are part of the present disclosure.

[0148] The term "epitope" refers to an antigenic determinant (e.g., on TfR) that interacts with the specific antigen binding site of an antigen binding protein, such as the variable region of an antibody, known as a paratope. A single antigen may have more than one epitope. Therefore, different antibodies can bind to different regions on the antigen and may have different biological effects. The term "epitope" may also refer to the site on the antigen to which B cells and / or T cells respond, and / or the region on the antigen that is bound by the antibody. An epitope can be defined as structural or functional. Functional epitopes are typically subsets of structural epitopes and have those residues that directly contribute to the affinity of the interaction. An epitope can be a linear epitope or a conformational epitope, i.e., composed of nonlinear amino acids. In certain embodiments, an epitope may include a determinant that is a chemically active surface group of a molecule (such as an amino acid, a sugar side chain, a phosphoryl group, or a sulfonyl group), and in certain embodiments, may have specific three-dimensional structural features and / or specific charge characteristics. The epitope to which the antigen binding proteins described herein bind may be included in a fragment of TfR (e.g., its extracellular domain). Antigen binding proteins (eg, antibodies) described herein that bind to such epitopes are also contemplated.

[0149] Methods for determining the epitope of an antigen-binding protein (e.g., an antibody or fragment or polypeptide) include alanine scanning mutation analysis, peptide blot analysis (Reineke (2004) Methods Mol. Biol. 248: 443-63), peptide cleavage analysis, crystallographic studies, and NMR analysis. In addition, methods such as epitope excision, epitope extraction, and chemical modification of the antigen can be employed (Tomer (2000) Prot. Sci. 9: 487-496). Another method that can be used to identify amino acids within a polypeptide with which an antigen-binding protein (e.g., an antibody or fragment or polypeptide) interacts is by mass spectrometry to detect hydrogen / deuterium exchange. See, for example, Ehring (1999) Analytical Biochemistry 267: 252-259; Engen and Smith (2001) Anal. Chem. 73: 256A-265A.

[0150] The present disclosure includes antigen-binding proteins that compete with antigen-binding proteins as described herein for binding to TfR epitopes as discussed herein. As used herein, the term "competition" refers to that an antigen-binding protein (e.g., an antibody or its antigen-binding fragment) binds to an antigen (e.g., TfR) and inhibits or blocks another antigen-binding protein (e.g., an antibody or its antigen-binding fragment) from binding to the antigen. Unless otherwise indicated, the term also includes competition between two antigen-binding proteins (e.g., antibodies) in two orientations, that is, the first antibody binds to the antigen and blocks the second antibody from binding to the antigen, or vice versa. Therefore, in one embodiment, competition occurs in such an orientation. In certain embodiments, the first antigen-binding protein (e.g., an antibody) and the second antigen-binding protein (e.g., an antibody) can be bound to the same epitope. Alternatively, the first antigen-binding protein and the second antigen-binding protein (e.g., an antibody) can be bound to different but, for example, overlapping or non-overlapping epitopes, wherein the binding of one antigen-binding protein inhibits or blocks the binding of the second antibody, for example, via steric hindrance. Competition between antigen binding proteins (e.g., antibodies) can be measured by methods known in the art, for example, by real-time, label-free bio-layer interferometry. Additionally, binding competition between TfR binding proteins (e.g., monoclonal antibodies (mAbs)) can be determined using real-time, label-free bio-layer interferometry on an Octet RED384 biosensor (PallForteBio Corp.).

[0151] Typically, the antibodies or antigen-binding fragments modified in some manner as described herein retain the ability to specifically bind to TfR, for example, when expressing their TfR binding activity on a molar basis, retain at least 10% of that activity (when compared to the parent antibody). Preferably, the antibodies or antigen-binding fragments described herein retain at least 20%, 50%, 70%, 80%, 90%, 95% or 100% or more of the TfR binding affinity of the parent antibody. It is also contemplated that the antibodies or antigen-binding fragments described herein may include conservative or non-conservative amino acid substitutions that do not substantially change their biological activity (referred to as "conservative variants" or "function-conservative variants" of the antibody).

[0152] The anti-TfR antigen binding proteins described herein can be monoclonal antibodies or antigen binding fragments of monoclonal antibodies, which can be conjugated to a molecular cargo. The present disclosure includes monoclonal anti-TfR antigen binding proteins, such as antibodies and antigen binding fragments thereof, and monoclonal compositions comprising a plurality of isolated monoclonal antigen binding proteins. As used herein, the term "monoclonal antibody" or "mAb" refers to a member of a substantially homogeneous antibody population, i.e., the amino acid sequences of the antibody molecules constituting the antibody population are identical, except for some mutations that may be present in small amounts in nature. "Multiple" such monoclonal antibodies and fragments in the composition refer to the same (i.e., as discussed above, the amino acid sequences are identical, except for some mutations that may be present in small amounts in nature) antibodies and fragments at a concentration higher than that typically found in nature (e.g., in the blood of a host organism such as a mouse or a human).

[0153] In one embodiment, the anti-TfR antigen binding protein, e.g., an antibody or antigen binding fragment (which may be conjugated to a molecular cargo) comprises, for example, a heavy chain constant domain of the IgA (e.g., IgA1 or IgA2), IgD, IgE, IgG (e.g., lgG1, lgG2, lgG3, and lgG4), or IgM type. In one embodiment, the antigen binding protein (e.g., an antibody or antigen binding fragment) comprises a light chain constant domain of, for example, a kappa or lambda type. In one embodiment, the V H linked to a human heavy chain constant domain (e.g., IgG), and as shown herein V L Linked to a human light chain constant domain (eg, kappa). The present disclosure includes antigen binding proteins comprising the variable domains set forth herein linked to a heavy chain constant domain and / or a light chain constant domain, eg, as set forth herein.

[0154] The present disclosure includes human anti-TfR antigen-binding proteins that can be conjugated to molecular cargoes. As used herein, the term "human" antigen-binding proteins (such as antibodies or antigen-binding fragments) include antibodies and fragments having variable and constant regions derived from human germline immunoglobulin sequences, whether in human cells or transplanted into non-human cells (e.g., mouse cells). See, for example, U.S. Patent Nos. 8,502,018; 6,596,541 or 5,789,215. The anti-TfR human mAbs described herein may include amino acid residues that are not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutations in vivo), for example, in CDRs, particularly in CDR3. However, as used herein, the term "human antibody" is not intended to include mAbs in which CDR sequences derived from the germline of another mammalian species (e.g., mouse) have been transplanted onto human FR sequences. The term includes antibodies recombinantly produced in non-human mammals or cells of non-human mammals. The term is not intended to include naturally occurring antibodies isolated directly from a human subject.The present disclosure includes human antigen binding proteins (eg, antibodies or antigen-binding fragments thereof described herein).

[0155] The present disclosure includes anti-TfR chimeric antigen binding proteins, such as antibodies and antigen-binding fragments thereof (which can be conjugated to molecular cargoes), and methods of use thereof. As used herein, a "chimeric antibody" is an antibody having a variable domain from a first antibody and a constant domain from a second antibody, wherein the first antibody and the second antibody are from different species (see, e.g., US4816567; and Morrison et al., (1984) Proc. Natl. Acad. Sci. USA 81: 6851-6855). The present disclosure includes chimeric antibodies having variable domains and non-human constant domains as described herein.

[0156] The term "recombinant" anti-TfR antigen binding protein such as an antibody or an antigen binding fragment thereof (which may be conjugated to a molecular cargo) refers to such molecules produced, expressed, isolated, or obtained by techniques or methods known in the art, such as recombinant DNA technology (such techniques include, for example, DNA splicing and transgenic expression). The term includes antibodies expressed in non-human mammals (including transgenic non-human mammals, such as transgenic mice) or cells (e.g., CHO cells), such as cell expression systems, or antibodies isolated from recombinant combinatorial human antibody libraries. The present disclosure includes recombinant antigen binding proteins, such as the antibodies and antigen binding fragments described herein.

[0157] In one embodiment, an antigen-binding fragment of an antibody will contain less structure than that of an intact antibody, but will still specifically bind to an antigen, such as a TfR, for example, including at least one variable domain. The variable domain can be of any size or amino acid composition and will generally contain at least one (e.g., 3) CDRs that are adjacent to or in frame with one or more framework sequences. H domain and its associated V L In the antigen-binding fragment of the structural domain, V H domain and V L The domains can be positioned relative to each other in any suitable arrangement. For example, the variable region can be dimeric and contain V H -V H 、V H -V L or V L -V L Alternatively, the antigen-binding fragment of an antibody may contain non-covalently bound monomers V H and / or V L domain.

[0158] A "variant" of a polypeptide (such as an immunoglobulin chain) is one that comprises a variant identical to a reference amino acid sequence set forth herein (e.g.,SEQ ID NO: 2, 3, 4, 5, 7, 8, 9, 10, 12, 13, 14, 15, 17, 18, 19, 20, 22, 23, 24, 25, 27, 2 8, 29, 30, 32, 33, 34, 35, 37, 38, 39, 40, 42, 43, 44, 45, 47, 48, 49, 50, 52, 53 ,54,55,57,58,59,60,62,63,64,65,67,68,69,70,72,73,74,75,77,78, 79, 80, 82, 83, 84, 85, 87, 88, 89, 90, 92, 93, 94, 95, 97, 98, 99, 100, 102, 10 3, 104, 105, 107, 108, 109, 110, 112, 113, 114, 115, 117, 118, 119, 120, 122, 123, 124, 125, 127, 128, 129, 130, 132, 133, 134, 135, 137, 138, 139, 140, 142, 143, 144, 145, 147, 148, 149, 150, 152, 153, 154, 155, 157, 158, 159, 160, 162, 163, 164, 165, 167, 168, 169, 170, 172, 173, 174, 175, 177, 178, 179 9, 180, 182, 183, 184, 185, 187, 188, 189, 190, 192, 193, 194, 195, 197, 198, 199, 200, 202, 203, 204, 205, 207, 208, 209, 210, 212, 213, 214, 215, 217, 218, 219, 220, 222, 223, 224, 225, 227, 228, 229, 230, 232, 233, 234, 235, 237, 238, 239, 240, 242, 243, 244, 245, 247, 248, 249, 250, 252, 253, 254, 2 55, 257, 258, 259, 260, 262, 263, 264, 265, 267, 268, 269, 270, 272, 273, 274, 275, 277, 278, 279, 280, 282, 283, 284, 285, 287, 288, 289, 290, 292, 293, 294, 295, 297, 298, 299, 300, 302, 303, 304, 305, 307, 527, 308, 309, 310, 312, 313, 314, 315, 317, 318, 319, 320, and 328-423) at least about 70% to 99.9% (e.g.,at least 70%, 72%, 74%, 75%, 76%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%) identical or similar amino acid sequences; wherein the parameters of the algorithm are selected to give the maximum match between the corresponding sequences over the entire length of the corresponding reference sequence (e.g., expect threshold: 10; word length: 3; maximum match in query range: 0; BLOSUM 62 matrix; gap penalty: 11 for existence, 1 for extension; conditional combination score matrix adjustment); and / or a polypeptide comprising the amino acid sequence but having one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10) mutations (e.g., point mutations, insertions, truncations and / or deletions). ,

[0159] In addition, variants of polypeptides can include polypeptides such as immunoglobulin chains, which can include the amino acid sequence of a reference polypeptide (the amino acid sequence of the reference polypeptide is specifically set forth herein), but have one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) mutations, for example, one or more missense mutations (e.g., conservative substitutions), nonsense mutations, deletions, or insertions. For example, the present disclosure includes TfR binding proteins comprising: an immunoglobulin light chain (or V L ) variant having an amino acid sequence as set forth in SEQ ID NO: 7, 17, 27, 37, 465, 47, 466, 57, 468, 67, 469, 77, 471, 87, 97, 107, 117, 474, 127, 137, 147, 476, 157, 167, 177, 187, 479, 197, 207, 217, 227, 237, 247, 257, 267, 277, 287, 297, 307, 527, 317, 484, but having one or more such mutations; and / or an immunoglobulin heavy chain (or V H) variant having the amino acid sequence set forth in SEQ ID NO: 2, 462, 12, 463, 22, 464, 32, 42, 52, 467, 62, 492, 72, 470, 82, 92, 472, 102, 112, 473, 122, 132, 142, 475, 152, 162, 477, 172, 182, 478, 192, 480, 202, 481, 212, 222, 232, 242, 252, 482, 262, 272, 282, 292, 302, 483, 312, but having one or more such mutations. In one embodiment, the TfR binding protein comprises: an immunoglobulin light chain variant comprising CDR-L1, CDR-L2 and CDR-L3, wherein one or more (e.g., 1, 2 or 3) such CDRs have one or more such mutations (e.g., conservative substitutions); and / or an immunoglobulin heavy chain variant comprising CDR-H1, CDR-H2 and CDR-H3, wherein one or more (e.g., 1, 2 or 3) such CDRs have one or more such mutations (e.g., conservative substitutions).

[0160] The following references are related to the BLAST algorithm commonly used for sequence analysis: BLAST ALGORITHMS: Altschul et al., (2005) FEBS J. 272(20):5101-5109; Altschul, SF et al., (1990) J. Mol. Biol. 215:403-410; Gish, W. et al., (1993) Nature Genet. 3:266-272; Madden, TL et al., (1996) Meth. Enzymol. 266:131-141; Altschul, SF et al., (1997) Nucleic Acids Res. 25:3389-3402; Zhang, J. et al., (1997) Genome Res.7:649-656; Wootton, JC et al., (1993) Comput. Chem. 17:149-163; Hancock, JM et al., (1994) Comput. Appl. Biosci. 10:67-70; Alignment scoring system: Dayhoff, MO et al., "A model of evolutionary change in proteins.", Atlas of Protein Sequence and Structure, (1978) Vol. 5 Suppl. 3, MO Dayhoff (ed.), pp. 345-352, Natl. Biomed. Res. Found., Washington, DC; Schwartz, RM et al., "Matrices for detecting distant relationships.", Atlas of Protein Sequence and Structure, (1978) Vol. 5 Suppl. 3, MO Dayhoff (ed.), pp. 353-358, Natl. Biomed. Res. Found., Washington, DC; Altschul, SF, (1991) J. Mol. Biol. 219:555-565; States, DJ et al., (1991) Methods 3:66-70; Henikoff, S. et al., (1992) Proc. Natl. Acad. Sci. USA 89:10915-10919; Altschul, SF et al., (1993) J. Mol. Evol. 36:290-300; ALIGNMENT STATISTICS: Karlin, S. et al., (1990) Proc. Natl. Acad. Sci.USA 87:2264-2268; Karlin, S. et al., (1993) Proc. Natl. Acad. Sci. USA 90:5873-5877; Dembo, A. et al., (1994) Ann. Prob. 22:2022-2039; and Altschul, SF, "Evaluating the statistical significance of multiple distinct local alignments.", Theoretical and Computational Methods in Genome Research (S. Suhai, ed.), (1997) pp. 1-14, Plenum, NY.

[0161] "Conservatively modified variants" or "conservative substitutions" (e.g., of the immunoglobulin chains described herein) refer to variants in which one or more amino acids in the polypeptide are substituted with other amino acids having similar characteristics (e.g., charge, side chain size, hydrophobicity / hydrophilicity, main-chain conformation and rigidity, etc.). Such changes can be made frequently without significantly disrupting the biological activity of the antibody or fragment. Those skilled in the art recognize that, in general, single amino acid substitutions in non-essential regions of a polypeptide do not substantially alter biological activity (see, e.g., Watson et al., (1987) Molecular Biology of the Gene, The Benjamin / Cummings Pub. Co., p. 224 (4th ed.)). In addition, substitutions of amino acids that are structurally or functionally similar are unlikely to significantly disrupt biological activity. The present disclosure includes TfR binding proteins containing such conservatively modified variant immunoglobulin chains.

[0162] Examples of groups of amino acids with chemically similar side chains include: 1) aliphatic side chains: glycine, alanine, valine, leucine, and isoleucine; 2) aliphatic-hydroxy side chains: serine and threonine; 3) amide-containing side chains: asparagine and glutamine; 4) aromatic side chains: phenylalanine, tyrosine, and tryptophan; 5) basic side chains: lysine, arginine, and histidine; 6) acidic side chains: aspartic acid and glutamic acid, and 7) sulfur-containing side chains: cysteine ​​and methionine. Alternatively, a conservative substitution is any change that has a positive value in the PAM250 log-likelihood matrix disclosed in Gonnet et al., (1992) Science 256:1443-45.

[0163] The antibodies and antigen-binding fragments described herein comprise immunoglobulin chains comprising the amino acid sequences (and variants thereof) specifically shown herein, and cellular post-translational modifications and in vitro post-translational modifications to the antibodies or fragments. For example, the present disclosure includes antibodies and antigen-binding fragments thereof that specifically bind to TfR having a heavy chain amino acid sequence and / or a light chain amino acid sequence shown herein, and antibodies and fragments in which one or more asparagine, serine and / or threonine residues are glycosylated, one or more asparagine residues are deamidated, one or more residues (e.g., Met, Trp and / or His) are oxidized, the N-terminal glutamine is pyroglutamate (pyroE) and / or the C-terminal lysine or other amino acid is missing.

[0164] In one embodiment, the anti-hTfR protein-drug conjugate (e.g., in the form of a scFv, Fab, or other antibody or antigen-binding fragment thereof) may exhibit one or more of the following characteristics:

[0165] Binding affinity to human TfR at 25°C in surface plasmon resonance format (K D ) has an affinity of about 41 nM or greater (e.g., about 1 nM or 0.1 nM, or about 0.18 nM to about 1.2 nM, or greater);

[0166] Binding affinity to monkey TfR at 25°C in surface plasmon resonance format (K D ) has an affinity of about 0 nM (no detectable binding) or higher (e.g., about 20 nM or higher);

[0167] K binding to monkey TfR / human TfR at 25°C in surface plasmon resonance format D The ratio is 0 to 278 (e.g., about 17 or 18);

[0168] When in Fab format (IgG1), blocks about 3%, 5%, 10% or 13% of hTfR (e.g., Hmm-hTFRC, such as REGN2431) binding to human Holo-Tf, e.g., no more than about 45% blockade;

[0169] When scFv (V K -V H ) form, blocks about 6%, 8%, 10% or 13% of hTfR (e.g., Hmm-hTFRC, such as REGN2431) binding to human Holo-Tf, e.g., no more than about 45% blockade;

[0170] When scFv (V H -V L) form, blocks about 11%, 17%, 23%, or 26% of hTfR (e.g., Hmm-hTFRC, such as REGN2431) binding to human Holo-Tf, e.g., no more than about 45% blockade;

[0171] *Tfrchum or Tfrchum / hum are homozygous knock-in mice.

[0172] The amino acid sequences of the domains in the anti-human transferrin receptor antigen binding proteins of the conjugates described herein are summarized in Table 1-1 below. For example, the present invention includes anti-human transferrin receptor 1 antibodies and antigen-binding fragments thereof (e.g., scFv and Fab) conjugated to a molecular cargo, which antibodies and antigen-binding fragments thereof comprise the HCVR and LCVR of the molecules in Table 1-1; or comprise the CDRs thereof.

[0173] Table 1-1. Antibodies, antigen-binding fragments (e.g., Fab or scFv molecules) in the protein-drug conjugates SEQ ID NO of the middle domain .

[0174]

[0175] 31874B

[0176] HCVR(V H ) nucleotide sequence

[0177]

[0178] HCVR(V H ) amino acid sequence

[0179]

[0180] or

[0181]

[0182] HCDR1: GFAFSSYA (SEQ ID NO: 3)

[0183] HCDR2: ISGTGGST (SEQ ID NO: 4)

[0184] HCDR3: AKGGAARRMEYFQY (SEQ ID NO: 5)

[0185] LCVR(V L ) nucleotide sequence

[0186]

[0187] LCVR(V L ) amino acid sequence

[0188]

[0189] LCDR1: QGISNY (SEQ ID NO: 8)

[0190] LCDR2: AAS (SEQ ID NO: 9)

[0191] LCDR3: QKYNSAPLT (SEQ ID NO: 10)

[0192] 31863B

[0193] HCVR(V H ) nucleotide sequence

[0194]

[0195] HCVR(V H ) amino acid sequence

[0196]

[0197] or

[0198]

[0199] HCDR1:GFTFNSYA (SEQ ID NO: 13)

[0200] HCDR2: IGGSTGNT (SEQ ID NO: 14)

[0201] HCDR3: AKGGAARRMEYFQH (SEQ ID NO: 15)

[0202] LCVR(V L ) nucleotide sequence

[0203]

[0204] LCVR(V L ) amino acid sequence

[0205]

[0206] LCDR1:QGISNY(SEQ ID NO:18)

[0207] LCDR2: AAS (SEQ ID NO: 19)

[0208] LCDR3: QNHNSVPLT (SEQ ID NO: 20) 69348

[0210] HCVR(V H ) nucleotide sequence

[0211]

[0212] HCVR(V H ) amino acid sequence

[0213]

[0214] or

[0215]

[0216] HCDR1: GFTFTTYG (SEQ ID NO: 23)

[0217] HCDR2: IWYDGSNK (SEQ ID NO: 24)

[0218] HCDR3: TRTHGYTRSSDGFDY (SEQ ID NO: 25)

[0219] LCVR(V L ) nucleotide sequence

[0220]

[0221] LCVR(V L ) amino acid sequence

[0222]

[0223] LCDR1: QSIRNV (SEQ ID NO: 28)

[0224] LCDR2: AAS (SEQ ID NO: 29)

[0225] LCDR3: LQHNFYPLT (SEQ ID NO: 30) 69340

[0227] HCVR(V H ) nucleotide sequence

[0228]

[0229]

[0230] HCVR(V H ) amino acid sequence

[0231]

[0232] HCDR1:GFTFDDKA (SEQ ID NO: 33)

[0233] HCDR2: ISWNSGTI (SEQ ID NO: 34)

[0234] HCDR3: AKDGDTSGWYWYGLDV (SEQ ID NO: 35)

[0235] LCVR(V L ) nucleotide sequence

[0236]

[0237] LCVR(V L ) amino acid sequence

[0238]

[0239] or

[0240]

[0241] LCDR1: QSVSSY (SEQ ID NO: 38)

[0242] LCDR2: DVS (SEQ ID NO: 39)

[0243] LCDR3: QQRSDWPIT (SEQ ID NO: 40) 69331

[0245] HCVR(V H ) nucleotide sequence

[0246]

[0247] HCVR(V H ) amino acid sequence

[0248]

[0249] HCDR1:GFTFSVYG (SEQ ID NO: 43)

[0250] HCDR2:ISHDGNIK(SEQ ID NO:44)

[0251] HCDR3: AKDTWNSLDTFDI (SEQ ID NO: 45)

[0252] LCVR(V L ) nucleotide sequence

[0253]

[0254] LCVR(V L ) amino acid sequence

[0255]

[0256] or

[0257]

[0258] LCDR1: QGISSY (SEQ ID NO: 48)

[0259] LCDR2: AAS (SEQ ID NO: 49)

[0260] LCDR3: QQLNSYPLT (SEQ ID NO: 50) 69332

[0262] HCVR(V H ) nucleotide sequence

[0263]

[0264] HCVR(V H ) amino acid sequence

[0265]

[0266] or

[0267]

[0268] HCDR1: GFSLNTYGMF (SEQ ID NO: 53)

[0269] HCDR2: IHWDDDK (SEQ ID NO: 54)

[0270] HCDR3:ARGHNNLNYIIH (SEQ ID NO: 55)

[0271] LCVR(V L ) nucleotide sequence

[0272]

[0273] LCVR(V L ) amino acid sequence

[0274]

[0275] or

[0276]

[0277] LCDR1: QGIRND (SEQ ID NO: 58)

[0278] LCDR2: AAS (SEQ ID NO: 59)

[0279] LCDR3: LQDYNYPFT (SEQ ID NO: 60) 69326

[0281] HCVR(V H ) nucleotide sequence

[0282]

[0283] HCVR(V H ) amino acid sequence

[0284]

[0285] or

[0286]

[0287] HCDR1: GFIFSSYE (SEQ ID NO: 63)

[0288] HCDR2: ISSSGSTI (SEQ ID NO: 64)

[0289] HCDR3: VSGVVLFDV (SEQ ID NO: 65)

[0290] LCVR(V L ) nucleotide sequence

[0291]

[0292] LCVR(V L ) amino acid sequence

[0293]

[0294] or

[0295]

[0296] LCDR1: QSVSSN (SEQ ID NO: 68)

[0297] LCDR2:SAS (SEQ ID NO: 69)

[0298] LCDR3: QQYNIWPRT (SEQ ID NO: 70) 69329

[0300] HCVR(V H ) nucleotide sequence

[0301]

[0302] HCVR(V H ) amino acid sequence

[0303]

[0304] or

[0305]

[0306] HCDR1: GTFFSNYW (SEQ ID NO: 73)

[0307] HCDR2:IKEDGSEK(SEQ ID NO:74)

[0308] HCDR3: ARDGEQLVDYYYYYVMDV (SEQ ID NO: 75)

[0309] LCVR(V L ) nucleotide sequence

[0310]

[0311] LCVR(V L ) amino acid sequence

[0312]

[0313] or

[0314]

[0315] LCDR1: QGISSW (SEQ ID NO: 78)

[0316] LCDR2: AAS (SEQ ID NO: 79)

[0317] LCDR3: QKANSFPYT (SEQ ID NO: 80) 69323

[0319] HCVR(V H ) nucleotide sequence

[0320]

[0321] HCVR(V H ) amino acid sequence

[0322]

[0323] HCDR1: GTFFDDYA (SEQ ID NO: 83)

[0324] HCDR2: ISWNSGYI (SEQ ID NO: 84)

[0325] HCDR3: ARGGSTLVRGVKGGYYGMDV (SEQ ID NO: 85)

[0326] LCVR(V L ) nucleotide sequence

[0327]

[0328] LCVR(V L ) amino acid sequence

[0329]

[0330] LCDR1: QSISSY (SEQ ID NO: 88)

[0331] LCDR2: AAS (SEQ ID NO: 89)

[0332] LCDR3: QQSYSIPLT (SEQ ID NO: 90) 69305

[0334] HCVR(V H ) nucleotide sequence

[0335]

[0336] HCVR(V H ) amino acid sequence

[0337]

[0338] or

[0339]

[0340] HCDR1: GTFFSSYG (SEQ ID NO: 93)

[0341] HCDR2: IWYDGSNK (SEQ ID NO: 94)

[0342] HCDR3: AGQLDLFDY (SEQ ID NO: 95)

[0343] LCVR(V L ) nucleotide sequence

[0344]

[0345] LCVR(V L ) amino acid sequence

[0346]

[0347] LCDR1: QSIDRY (SEQ ID NO: 98)

[0348] LCDR2: TTS (SEQ ID NO: 99)

[0349] LCDR3: QQSYSPPLT (SEQ ID NO: 100) 69307

[0351] HCVR(V H ) nucleotide sequence

[0352]

[0353] HCVR(V H ) amino acid sequence

[0354]

[0355] HCDR1: GTFFSNYW (SEQ ID NO: 103)

[0356] HCDR2:IKEDGSEK(SEQ ID NO:104)

[0357] HCDR3: ARDGEQLVDYYYYYVMDV (SEQ ID NO: 105)

[0358] LCVR(V L ) nucleotide sequence

[0359]

[0360] LCVR(V L ) amino acid sequence

[0361]

[0362] LCDR1: QGISSW (SEQ ID NO: 108)

[0363] LCDR2: AAS (SEQ ID NO: 109)

[0364] LCDR3: QKADSLPYA (SEQ ID NO: 110)

[0365] 12795B

[0366] HCVR(V H ) nucleotide sequence

[0367]

[0368] HCVR(V H ) amino acid sequence

[0369]

[0370] or

[0371]

[0372] HCDR1: GFTFTSYD (SEQ ID NO: 113)

[0373] HCDR2: ISGSGGNT (SEQ ID NO: 114)

[0374] HCDR3: TRSHDFGAFDYFDY (SEQ ID NO: 115)

[0375] LCVR(V L ) nucleotide sequence

[0376]

[0377]

[0378] LCVR(V L ) amino acid sequence

[0379]

[0380] or

[0381]

[0382] LCDR1: QGIRDH (SEQ ID NO: 118)

[0383] LCDR2: AAS (SEQ ID NO: 119)

[0384] LCDR3: LQYDTYPLT (SEQ ID NO: 120)

[0385] 12798B

[0386] HCVR(V H ) nucleotide sequence

[0387]

[0388] HCVR(V H ) amino acid sequence

[0389]

[0390] HCDR1: GTFFDDYA (SEQ ID NO: 123)

[0391] HCDR2: ISWNSATR (SEQ ID NO: 124)

[0392] HCDR3: AKDMDISLGYYGLDV (SEQ ID NO: 125)

[0393] LCVR(V L ) nucleotide sequence

[0394]

[0395] LCVR(V L ) amino acid sequence

[0396]

[0397] LCDR1: QTVSSN (SEQ ID NO: 128)

[0398] LCDR2: GSS (SEQ ID NO: 129)

[0399] LCDR3: QQYNNWPPYT (SEQ ID NO: 130)

[0400] 12799B

[0401] HCVR(V H ) nucleotide sequence

[0402]

[0403] HCVR(V H ) amino acid sequence

[0404]

[0405] HCDR1:GFSLSTSGVG (SEQ ID NO: 133)

[0406] HCDR2: IYWNDHK (SEQ ID NO: 134)

[0407] HCDR3: AHYSGSYSYYYYGLDV (SEQ ID NO: 135)

[0408] LCVR(V L ) nucleotide sequence

[0409]

[0410] LCVR(V L ) amino acid sequence

[0411]

[0412] LCDR1: QGIASW (SEQ ID NO: 138)

[0413] LCDR2: AAS (SEQ ID NO: 139)

[0414] LCDR3: QQANYFPWT (SEQ ID NO: 140)

[0415] 12801B

[0416] HCVR(V H ) nucleotide sequence

[0417]

[0418] HCVR(V H ) amino acid sequence

[0419]

[0420] or

[0421]

[0422] HCDR1: GFTFTSYA (SEQ ID NO: 143)

[0423] HCDR2: IRGSGGGT (SEQ ID NO: 144)

[0424] HCDR3: ARSHDYGAFDFFDY (SEQ ID NO: 145)

[0425] LCVR(V L) nucleotide sequence

[0426]

[0427] LCVR(V L ) amino acid sequence

[0428]

[0429] or

[0430]

[0431] LCDR1: QGIRTD (SEQ ID NO: 148)

[0432] LCDR2: AAS (SEQ ID NO: 149)

[0433] LCDR3: LQYNSYPLT (SEQ ID NO: 150)

[0434] 12802B

[0435] HCVR(V H ) nucleotide sequence

[0436]

[0437] HCVR(V H ) amino acid sequence

[0438]

[0439] HCDR1: GTFFSDYF (SEQ ID NO: 153)

[0440] HCDR2: ISSTGSTI (SEQ ID NO: 154)

[0441] HCDR3: TRDNWNYEY (SEQ ID NO: 155)

[0442] LCVR(V L ) nucleotide sequence

[0443]

[0444] LCVR(V L ) amino acid sequence

[0445]

[0446] LCDR1: QSVSIN (SEQ ID NO: 158)

[0447] LCDR2:VAS (SEQ ID NO: 159)

[0448] LCDR3: QQYDIWPYT (SEQ ID NO: 160)

[0449] 12808B

[0450] HCVR(V H ) nucleotide sequence

[0451]

[0452] HCVR(V H ) amino acid sequence

[0453]

[0454] or

[0455]

[0456] HCDR1:GESISSNTYY(SEQ ID NO:163)

[0457] HCDR2: IDYSGTT (SEQ ID NO: 164)

[0458] HCDR3: AREWGNYGYYYGMDV (SEQ ID NO: 165)

[0459] LCVR(V L ) nucleotide sequence

[0460]

[0461] LCVR(V L ) amino acid sequence

[0462]

[0463] LCDR1: QGIRND (SEQ ID NO: 168)

[0464] LCDR2: AAS (SEQ ID NO: 169)

[0465] LCDR3: LSHNSYPWT (SEQ ID NO: 170)

[0466] 12812B

[0467] HCVR(V H ) nucleotide sequence

[0468]

[0469]

[0470] HCVR(V H ) amino acid sequence

[0471]

[0472] HCDR1:RGTFSSYA (SEQ ID NO: 173)

[0473] HCDR2: IIPIFGTA (SEQ ID NO: 174)

[0474] HCDR3: AREKGWNYFDY (SEQ ID NO: 175)

[0475] LCVR(V L ) nucleotide sequence

[0476]

[0477] LCVR(V L ) amino acid sequence

[0478]

[0479] LCDR1: QGISSW (SEQ ID NO: 178)

[0480] LCDR2: AAS (SEQ ID NO: 179)

[0481] LCDR3: QQANSFPRT (SEQ ID NO: 180)

[0482] 12816B

[0483] HCVR(V H ) nucleotide sequence

[0484]

[0485] HCVR(V H ) amino acid sequence

[0486]

[0487] or

[0488]

[0489] HCDR1: GTFFSDYY (SEQ ID NO: 183)

[0490] HCDR2: ISSSGTTI (SEQ ID NO: 184)

[0491] HCDR3: AREGYGNDYYYYGIDV (SEQ ID NO: 185)

[0492] LCVR(V L ) nucleotide sequence

[0493]

[0494] LCVR(V L ) amino acid sequence

[0495]

[0496] or

[0497]

[0498] LCDR1: QSLLHGNGYNY (SEQ ID NO: 188)

[0499] LCDR2:LGS (SEQ ID NO: 189)

[0500] LCDR3: MQALQTPYT (SEQ ID NO: 190)

[0501] 12833B

[0502] HCVR(V H ) nucleotide sequence

[0503]

[0504] HCVR(V H ) amino acid sequence

[0505]

[0506] or

[0507]

[0508] HCDR1:GFTFSSFG (SEQ ID NO: 193)

[0509] HCDR2: ISYDGSDK (SEQ ID NO: 194)

[0510] HCDR3:AKENGILTDSYGMDV (SEQ ID NO: 195)

[0511] LCVR(V L ) nucleotide sequence

[0512]

[0513] LCVR(V L ) amino acid sequence

[0514]

[0515] LCDR1: QSISSY (SEQ ID NO: 198)

[0516] LCDR2: AAS (SEQ ID NO: 199)

[0517] LCDR3: QQSYSTPPIT (SEQ ID NO: 200)

[0518] 12834B

[0519] HCVR(V H ) nucleotide sequence

[0520]

[0521] HCVR(V H ) amino acid sequence

[0522]

[0523] or

[0524]

[0525] HCDR1: GYTFTSYG (SEQ ID NO: 203)

[0526] HCDR2: ISVYHGNT (SEQ ID NO: 204)

[0527] HCDR3: AREGYYDFWSGYYPFDY (SEQ ID NO: 205)

[0528] LCVR(V L ) nucleotide sequence

[0529]

[0530] LCVR(V L ) amino acid sequence

[0531]

[0532] LCDR1: QSISSY (SEQ ID NO: 208)

[0533] LCDR2: AAS (SEQ ID NO: 209)

[0534] LCDR3: QQSYSTPPIT (SEQ ID NO: 210)

[0535] 12835B

[0536] HCVR(V H ) nucleotide sequence

[0537]

[0538] HCVR(V H ) amino acid sequence

[0539]

[0540] HCDR1: GFTFRNYE (SEQ ID NO: 213)

[0541] HCDR2:ISSSGNMK(SEQ ID NO:214)

[0542] HCDR3: ARDEFPYGMDV (SEQ ID NO: 215)

[0543] LCVR(V L ) nucleotide sequence

[0544]

[0545] LCVR(V L ) amino acid sequence

[0546]

[0547] LCDR1: QSISSY (SEQ ID NO: 218)

[0548] LCDR2: AAS (SEQ ID NO: 219)

[0549] LCDR3: QQSYSTPPIT (SEQ ID NO: 220)

[0550] 12847B

[0551] HCVR(V H ) nucleotide sequence

[0552]

[0553] HCVR(V H ) amino acid sequence

[0554]

[0555] HCDR1: GTFFDDYA (SEQ ID NO: 223)

[0556] HCDR2: ISWSSGSM (SEQ ID NO: 224)

[0557] HCDR3: AKAREVGDYYGMDV (SEQ ID NO: 225)

[0558] LCVR(V L ) amino acid sequence

[0559]

[0560]

[0561] LCVR(V L ) amino acid sequence

[0562]

[0563] LCDR1: QSISSY (SEQ ID NO: 228)

[0564] LCDR2: AAS (SEQ ID NO: 229)

[0565] LCDR3: QQSYSTPPIT (SEQ ID NO: 230)

[0566] 12848B

[0567] HCVR(V H ) nucleotide sequence

[0568]

[0569] HCVR(V H ) amino acid sequence

[0570]

[0571] HCDR1:GFTFDNFG (SEQ ID NO: 233)

[0572] HCDR2:LTWNSGVI (SEQ ID NO: 234)

[0573] HCDR3:AKDIRNYGPFDY (SEQ ID NO: 235)

[0574] LCVR(V L ) amino acid sequence

[0575]

[0576] LCVR(V L ) amino acid sequence

[0577]

[0578] LCDR1: QSVSSSY (SEQ ID NO: 238)

[0579] LCDR2: GAS (SEQ ID NO: 239)

[0580] LCDR3: QQYGSSPWT (SEQ ID NO: 240)

[0581] 12843B

[0582] HCVR(V H ) nucleotide sequence

[0583]

[0584] HCVR(V H ) amino acid sequence

[0585]

[0586] HCDR1:GFTFNIFE (SEQ ID NO: 243)

[0587] HCDR2: ISSRTTTT (SEQ ID NO: 244)

[0588] HCDR3: ARDYEATIPFDF (SEQ ID NO: 245)

[0589] LCVR(V L ) nucleotide sequence

[0590]

[0591] LCVR(V L ) amino acid sequence

[0592]

[0593] LCDR1: QSISSY (SEQ ID NO: 248)

[0594] LCDR2: AAS (SEQ ID NO: 249)

[0595] LCDR3: QQSYSTPPIT (SEQ ID NO: 250)

[0596] 12844B

[0597] HCVR(V H ) nucleotide sequence

[0598]

[0599] HCVR(V H ) amino acid sequence

[0600]

[0601] or

[0602]

[0603] HCDR1: GTFFDDYG (SEQ ID NO: 253)

[0604] HCDR2: INWNGDRT (SEQ ID NO: 254)

[0605] HCDR3: ARDQGLGVAATLDY (SEQ ID NO: 255)

[0606] LCVR(V L ) nucleotide sequence

[0607]

[0608] LCVR(V L ) amino acid sequence

[0609]

[0610] LCDR1: QSISSY (SEQ ID NO: 258)

[0611] LCDR2: AAS (SEQ ID NO: 259)

[0612] LCDR3: QQSYSTPPIT (SEQ ID NO: 260)

[0613] 12845B

[0614] HCVR(V H ) nucleotide sequence

[0615]

[0616]

[0617] HCVR(V H ) amino acid sequence

[0618]

[0619] HCDR1:GFTVSNYE (SEQ ID NO: 263)

[0620] HCDR2:ISSSTSNI(SEQ ID NO:264)

[0621] HCDR3: VRDGIVVVPVGRGYYYYGLDV (SEQ ID NO: 265)

[0622] LCVR(V L ) nucleotide sequence

[0623]

[0624] LCVR(V L ) amino acid sequence

[0625]

[0626] LCDR1: QSISSY (SEQ ID NO: 268)

[0627] LCDR2: AAS (SEQ ID NO: 269)

[0628] LCDR3: QQSYSTPPIT (SEQ ID NO: 270)

[0629] 12839B

[0630] HCVR(V H ) nucleotide sequence

[0631]

[0632] HCVR(V H ) amino acid sequence

[0633]

[0634] HCDR1: GFPFSNYV (SEQ ID NO: 273)

[0635] HCDR2: IFFDGKKN (SEQ ID NO: 274)

[0636] HCDR3: AKIHCPNGVCYKGYYGMDV (SEQ ID NO: 275)

[0637] LCVR(V L ) nucleotide sequence

[0638]

[0639] LCVR(V L ) amino acid sequence

[0640]

[0641] LCDR1: QSISSY (SEQ ID NO: 278)

[0642] LCDR2: AAS (SEQ ID NO: 279)

[0643] LCDR3: QQSYSTPPIT (SEQ ID NO: 280)

[0644] 12841B

[0645] HCVR(V H ) nucleotide sequence

[0646]

[0647] HCVR(V H ) amino acid sequence

[0648]

[0649] HCDR1: GTFFSNYW (SEQ ID NO: 283)

[0650] HCDR2:IKEDGGKK(SEQ ID NO:284)

[0651] HCDR3: AREDTTLVVDYYYYGMDV (SEQ ID NO: 285)

[0652] LCVR(V L ) nucleotide sequence

[0653]

[0654] LCVR(V L ) amino acid sequence

[0655]

[0656] LCDR1: QSISSY (SEQ ID NO: 288)

[0657] LCDR2: AAS (SEQ ID NO: 289)

[0658] LCDR3: QQSYSTPPIT (SEQ ID NO: 290)

[0659] 12850B

[0660] HCVR(V H ) nucleotide sequence

[0661]

[0662] HCVR(V H ) amino acid sequence

[0663]

[0664] HCDR1:GGTFNTYA (SEQ ID NO: 293)

[0665] HCDR2: IIPISGIA (SEQ ID NO: 294)

[0666] HCDR3: ASWNYALYYFYGMDV (SEQ ID NO: 295)

[0667] LCVR(V L ) nucleotide sequence

[0668]

[0669]

[0670] LCVR(V L ) amino acid sequence

[0671]

[0672] LCDR1: QSVSSSY (SEQ ID NO: 298)

[0673] LCDR2: GAS (SEQ ID NO: 299)

[0674] LCDR3: QQYGSSPWT (SEQ ID NO: 300) 69261

[0676] HCVR(VH ) nucleotide sequence

[0677]

[0678] HCVR(V H ) amino acid sequence

[0679]

[0680] or

[0681]

[0682] HCDR1:GFTFSVYY(SEQ ID NO:303)

[0683] HCDR2: ISSSGSTI (SEQ ID NO: 304)

[0684] HCDR3: GREGYSGTYSYYGMDV (SEQ ID NO: 305)

[0685] LCVR(V L ) nucleotide sequence

[0686]

[0687] LCVR(V L ) amino acid sequence

[0688]

[0689] or

[0690]

[0691] LCDR1: QSLLHSNGYNY (SEQ ID NO: 308)

[0692] LCDR2:LGS (SEQ ID NO:309)

[0693] LCDR3: MQALQTPYT (SEQ ID NO: 310) 69263

[0695] HCVR(V H ) nucleotide sequence

[0696]

[0697] HCVR(V H ) amino acid sequence

[0698]

[0699] HCDR1: GTFFDDYA (SEQ ID NO: 313)

[0700] HCDR2: ISWNSGTR (SEQ ID NO: 314)

[0701] HCDR3: VKDITISPNYYGMDV (SEQ ID NO: 315)

[0702] LCVR(V L ) nucleotide sequence

[0703]

[0704] LCVR(V L ) amino acid sequence

[0705]

[0706] or

[0707]

[0708] LCDR1: QDISHY (SEQ ID NO: 318)

[0709] LCDR2: AAS (SEQ ID NO: 319)

[0710] LCDR3: QKYNSVPLT (SEQ ID NO: 320)

[0711] As discussed, anti-hTfR scFv protein-drug conjugates (e.g., 31874B, 31863B, 69348, 69340, 69331, 69332, 69326, 69329, 69323, 69305, 69307, 12795B, 12798B, 12799B, 12801B, 12802B, 12808B, 12812B, 12816B , 12833B, 12834B, 12835B, 12847B, 12848B, 12843B, 12844B, 12845B, 12839B, 12841B, 12850B, 69261 or 69263) comprises an optional signal peptide (e.g., an mROR signal sequence) linked to a scFv (e.g., comprising a V L and V H ), linked to an optional linker, linked to a molecular cargo, wherein, for example:

[0712] (I)

[0713] An optional signal peptide is, for example, the signal peptide from Mus musculus Ror1 (e.g., consisting of amino acids MHRPRRRGTRPPPLALLAALLLAARGADA (SEQ ID NO: 528));

[0714] (II)

[0715] The scFv comprises (i) a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, wherein the HCVR has an amino acid sequence set forth in SEQ ID NO: 2, 462, 12, 463, 22, 464, 32, 42, 52, 467, 62, 492, 72, 470, 82, 92, 472, 102, 112, 473, 122, 132, 142, 475, 152, 162, 477, 172, 182, 478, 192, 480, 202, 481, 212, 222, 232, 242, 252, 482, 262, 272, 282, 292, 302, 483, or 312;

[0716] and / or

[0717] (ii) a light chain variable region comprising LCDR1, LCDR2, and LCDR3, the LCVR having the amino acid sequence set forth in SEQ ID NO: 7, 17, 27, 37, 465, 47, 466, 57, 468, 67, 469, 77, 471, 87, 97, 107, 117, 474, 127, 137, 147, 476, 157, 167, 177, 187, 479, 197, 207, 217, 227, 237, 247, 257, 267, 277, 287, 297, 307, 527, 317, or 484;

[0718] Or the scFv comprises:

[0719] (1) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 2 or 462 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 7 (or a variant thereof);

[0720] (2) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 12 or 463 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 17 (or a variant thereof);

[0721] (3) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 22 or 464 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 27 (or a variant thereof);

[0722] (4) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 32 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 37 or 465 (or a variant thereof);

[0723] (5) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 42 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 47 or 466 (or a variant thereof);

[0724] (6) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 52 or 467 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 57 or 468 (or a variant thereof);

[0725] (7) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 62 or 492 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 67 or 469 (or a variant thereof);

[0726] (8) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 72 or 470 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 77 or 471 (or a variant thereof);

[0727] (9) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 82 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 87 (or a variant thereof);

[0728] (10) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 92 or 472 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 97 (or a variant thereof);

[0729] (11) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 102 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 107 (or a variant thereof);

[0730] (12) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 112 or 473 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 117 or 474 (or a variant thereof);

[0731] (13) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 122 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 127 (or a variant thereof);

[0732] (14) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 132 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 137 (or a variant thereof);

[0733] (15) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 142 or 475 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 147 or 476 (or a variant thereof);

[0734] (16) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 152 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 157 (or a variant thereof);

[0735] (17) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 162 or 477 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 167 (or a variant thereof);

[0736] (18) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 172 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 177 (or a variant thereof);

[0737] (19) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 182 or 478 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 187 or 479 (or a variant thereof);

[0738] (20) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 192 or 480 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 197 (or a variant thereof);

[0739] (21) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 202 or 481 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 207 (or a variant thereof);

[0740] (22) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 212 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 217 (or a variant thereof);

[0741] (23) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 222 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 227 (or a variant thereof);

[0742] (24) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 232 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 237 (or a variant thereof);

[0743] (25) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 242 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 247 (or a variant thereof);

[0744] (26) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 252 or 482 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 257 (or a variant thereof);

[0745] (27) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 262 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 267 (or a variant thereof);

[0746] (28) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 272 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 277 (or a variant thereof);

[0747] (29) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 282 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 287 (or a variant thereof);

[0748] (30) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 292 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 297 (or a variant thereof);

[0749] (31) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 302 or 483 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 307 or 527 (or a variant thereof);

[0750] (32) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 312 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 317 or 484 (or a variant thereof);

[0751] Or the scFv comprises:

[0752] (a) a HCVR comprising:

[0753] HCDR1 having the amino acid sequence shown in SEQ ID NO: 3 (or a variant thereof),

[0754] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 4 (or a variant thereof), and

[0755] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 5 (or a variant thereof); and

[0756] An LCVR, the LCVR containing:

[0757] LCDR1 having the amino acid sequence shown in SEQ ID NO: 8 (or a variant thereof),

[0758] LCDR2 having the amino acid sequence shown in SEQ ID NO: 9 (or a variant thereof), and

[0759] LCDR3 having the amino acid sequence shown in SEQ ID NO: 10 (or a variant thereof);

[0760] (b) a HCVR comprising:

[0761] HCDR1 having the amino acid sequence shown in SEQ ID NO: 13 (or a variant thereof),

[0762] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 14 (or a variant thereof), and

[0763] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 15 (or a variant thereof); and

[0764] An LCVR, the LCVR containing:

[0765] LCDR1 having the amino acid sequence shown in SEQ ID NO: 18 (or a variant thereof),

[0766] LCDR2 having the amino acid sequence shown in SEQ ID NO: 19 (or a variant thereof), and

[0767] LCDR3 having the amino acid sequence shown in SEQ ID NO: 20 (or a variant thereof);

[0768] (c) a HCVR comprising:

[0769] HCDR1 having the amino acid sequence shown in SEQ ID NO: 23 (or a variant thereof),

[0770] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 24 (or a variant thereof), and

[0771] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 25 (or a variant thereof); and

[0772] An LCVR, the LCVR containing:

[0773] LCDR1 having the amino acid sequence shown in SEQ ID NO: 28 (or a variant thereof),

[0774] LCDR2 having the amino acid sequence shown in SEQ ID NO: 29 (or a variant thereof), and

[0775] LCDR3 having the amino acid sequence shown in SEQ ID NO: 30 (or a variant thereof);

[0776] (d) a HCVR comprising:

[0777] HCDR1 having the amino acid sequence shown in SEQ ID NO: 33 (or a variant thereof),

[0778] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 34 (or a variant thereof), and

[0779] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 35 (or a variant thereof); and

[0780] An LCVR, the LCVR containing:

[0781] LCDR1 having the amino acid sequence shown in SEQ ID NO: 38 (or a variant thereof),

[0782] LCDR2 having the amino acid sequence shown in SEQ ID NO: 39 (or a variant thereof), and

[0783] LCDR3 having the amino acid sequence shown in SEQ ID NO: 40 (or a variant thereof);

[0784] (e) a HCVR comprising:

[0785] HCDR1 having the amino acid sequence shown in SEQ ID NO: 43 (or a variant thereof),

[0786] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 44 (or a variant thereof), and

[0787] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 45 (or a variant thereof); and

[0788] An LCVR, the LCVR containing:

[0789] LCDR1 having the amino acid sequence shown in SEQ ID NO: 48 (or a variant thereof),

[0790] LCDR2 having the amino acid sequence shown in SEQ ID NO: 49 (or a variant thereof), and

[0791] LCDR3 having the amino acid sequence shown in SEQ ID NO: 50 (or a variant thereof);

[0792] (f) a HCVR comprising:

[0793] HCDR1 having the amino acid sequence shown in SEQ ID NO: 53 (or a variant thereof),

[0794] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 54 (or a variant thereof), and

[0795] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 55 (or a variant thereof); and

[0796] An LCVR, the LCVR containing:

[0797] LCDR1 having the amino acid sequence shown in SEQ ID NO: 58 (or a variant thereof),

[0798] LCDR2 having the amino acid sequence shown in SEQ ID NO: 59 (or a variant thereof), and

[0799] LCDR3 having the amino acid sequence shown in SEQ ID NO: 60 (or a variant thereof);

[0800] (g) a HCVR comprising:

[0801] HCDR1 having the amino acid sequence shown in SEQ ID NO: 63 (or a variant thereof),

[0802] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 64 (or a variant thereof), and

[0803] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 65 (or a variant thereof); and

[0804] An LCVR, the LCVR containing:

[0805] LCDR1 having the amino acid sequence shown in SEQ ID NO: 68 (or a variant thereof),

[0806] LCDR2 having the amino acid sequence shown in SEQ ID NO: 69 (or a variant thereof), and

[0807] LCDR3 having the amino acid sequence shown in SEQ ID NO: 70 (or a variant thereof);

[0808] (h) a HCVR comprising:

[0809] HCDR1 having the amino acid sequence shown in SEQ ID NO: 73 (or a variant thereof),

[0810] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 74 (or a variant thereof), and

[0811] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 75 (or a variant thereof); and

[0812] An LCVR, the LCVR containing:

[0813] LCDR1 having the amino acid sequence shown in SEQ ID NO: 78 (or a variant thereof),

[0814] LCDR2 having the amino acid sequence shown in SEQ ID NO: 79 (or a variant thereof), and

[0815] LCDR3 having the amino acid sequence shown in SEQ ID NO: 80 (or a variant thereof);

[0816] (i) a HCVR comprising:

[0817] HCDR1 having the amino acid sequence shown in SEQ ID NO: 83 (or a variant thereof),

[0818] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 84 (or a variant thereof), and

[0819] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 85 (or a variant thereof); and

[0820] An LCVR, the LCVR containing:

[0821] LCDR1 having the amino acid sequence shown in SEQ ID NO: 88 (or a variant thereof),

[0822] LCDR2 having the amino acid sequence shown in SEQ ID NO: 89 (or a variant thereof), and

[0823] LCDR3 having the amino acid sequence shown in SEQ ID NO: 90 (or a variant thereof);

[0824] (j) a HCVR comprising:

[0825] HCDR1 having the amino acid sequence shown in SEQ ID NO: 93 (or a variant thereof),

[0826] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 94 (or a variant thereof), and

[0827] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 95 (or a variant thereof); and

[0828] An LCVR, the LCVR containing:

[0829] LCDR1 having the amino acid sequence shown in SEQ ID NO: 98 (or a variant thereof),

[0830] LCDR2 having the amino acid sequence shown in SEQ ID NO: 99 (or a variant thereof), and

[0831] LCDR3 having the amino acid sequence shown in SEQ ID NO: 100 (or a variant thereof);

[0832] (k) a HCVR comprising:

[0833] HCDR1 having the amino acid sequence shown in SEQ ID NO: 103 (or a variant thereof),

[0834] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 104 (or a variant thereof), and

[0835] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 105 (or a variant thereof); and

[0836] An LCVR, the LCVR containing:

[0837] LCDR1 having the amino acid sequence shown in SEQ ID NO: 108 (or a variant thereof),

[0838] LCDR2 having the amino acid sequence shown in SEQ ID NO: 109 (or a variant thereof), and

[0839] LCDR3 having the amino acid sequence shown in SEQ ID NO: 110 (or a variant thereof);

[0840] (1) a HCVR comprising:

[0841] HCDR1 having the amino acid sequence shown in SEQ ID NO: 113 (or a variant thereof),

[0842] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 114 (or a variant thereof), and

[0843] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 115 (or a variant thereof); and

[0844] An LCVR, the LCVR containing:

[0845] LCDR1 having the amino acid sequence shown in SEQ ID NO: 118 (or a variant thereof),

[0846] LCDR2 having the amino acid sequence shown in SEQ ID NO: 119 (or a variant thereof), and

[0847] LCDR3 having the amino acid sequence shown in SEQ ID NO: 120 (or a variant thereof);

[0848] (m) a HCVR comprising:

[0849] HCDR1 having the amino acid sequence shown in SEQ ID NO: 123 (or a variant thereof),

[0850] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 124 (or a variant thereof), and

[0851] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 125 (or a variant thereof); and

[0852] An LCVR, the LCVR containing:

[0853] LCDR1 having the amino acid sequence shown in SEQ ID NO: 128 (or a variant thereof),

[0854] LCDR2 having the amino acid sequence shown in SEQ ID NO: 129 (or a variant thereof), and

[0855] LCDR3 having the amino acid sequence shown in SEQ ID NO: 130 (or a variant thereof);

[0856] (n) a HCVR comprising:

[0857] HCDR1 having the amino acid sequence shown in SEQ ID NO: 133 (or a variant thereof),

[0858] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 134 (or a variant thereof), and

[0859] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 135 (or a variant thereof); and

[0860] An LCVR, the LCVR containing:

[0861] LCDR1 having the amino acid sequence shown in SEQ ID NO: 138 (or a variant thereof),

[0862] LCDR2 having the amino acid sequence shown in SEQ ID NO: 139 (or a variant thereof), and

[0863] LCDR3 having the amino acid sequence shown in SEQ ID NO: 140 (or a variant thereof);

[0864] (o) a HCVR comprising:

[0865] HCDR1 having the amino acid sequence shown in SEQ ID NO: 143 (or a variant thereof),

[0866] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 144 (or a variant thereof), and

[0867] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 145 (or a variant thereof); and

[0868] An LCVR, the LCVR containing:

[0869] LCDR1 having the amino acid sequence shown in SEQ ID NO: 148 (or a variant thereof),

[0870] LCDR2 having the amino acid sequence shown in SEQ ID NO: 149 (or a variant thereof), and

[0871] LCDR3 having the amino acid sequence shown in SEQ ID NO: 150 (or a variant thereof);

[0872] (p) a HCVR comprising:

[0873] HCDR1 having the amino acid sequence shown in SEQ ID NO: 153 (or a variant thereof),

[0874] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 154 (or a variant thereof), and

[0875] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 155 (or a variant thereof);

[0876] and a LCVR comprising:

[0877] LCDR1 having the amino acid sequence shown in SEQ ID NO: 158 (or a variant thereof),

[0878] LCDR2 having the amino acid sequence shown in SEQ ID NO: 159 (or a variant thereof), and

[0879] LCDR3 having the amino acid sequence shown in SEQ ID NO: 160 (or a variant thereof);

[0880] (q) a HCVR comprising:

[0881] HCDR1 having the amino acid sequence shown in SEQ ID NO: 163 (or a variant thereof),

[0882] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 164 (or a variant thereof), and

[0883] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 165 (or a variant thereof);

[0884] and a LCVR comprising:

[0885] LCDR1 having the amino acid sequence shown in SEQ ID NO: 168 (or a variant thereof),

[0886] LCDR2 having the amino acid sequence shown in SEQ ID NO: 169 (or a variant thereof), and

[0887] LCDR3 having the amino acid sequence shown in SEQ ID NO: 170 (or a variant thereof);

[0888] (r) a HCVR comprising:

[0889] HCDR1 having the amino acid sequence shown in SEQ ID NO: 173 (or a variant thereof),

[0890] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 174 (or a variant thereof), and

[0891] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 175 (or a variant thereof); and

[0892] An LCVR, the LCVR containing:

[0893] LCDR1 having the amino acid sequence shown in SEQ ID NO: 178 (or a variant thereof),

[0894] LCDR2 having the amino acid sequence shown in SEQ ID NO: 179 (or a variant thereof), and

[0895] LCDR3 having the amino acid sequence shown in SEQ ID NO: 180 (or a variant thereof);

[0896] (s) a HCVR comprising:

[0897] HCDR1 having the amino acid sequence shown in SEQ ID NO: 183 (or a variant thereof),

[0898] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 184 (or a variant thereof), and

[0899] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 185 (or a variant thereof); and

[0900] An LCVR, the LCVR containing:

[0901] LCDR1 having the amino acid sequence shown in SEQ ID NO: 188 (or a variant thereof),

[0902] LCDR2 having the amino acid sequence shown in SEQ ID NO: 189 (or a variant thereof), and

[0903] LCDR3 having the amino acid sequence shown in SEQ ID NO: 190 (or a variant thereof);

[0904] (t) a HCVR comprising:

[0905] HCDR1 having the amino acid sequence shown in SEQ ID NO: 193 (or a variant thereof),

[0906] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 194 (or a variant thereof), and

[0907] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 195 (or a variant thereof); and

[0908] An LCVR, the LCVR containing:

[0909] LCDR1 having the amino acid sequence shown in SEQ ID NO: 198 (or a variant thereof),

[0910] LCDR2 having the amino acid sequence shown in SEQ ID NO: 199 (or a variant thereof), and

[0911] LCDR3 having the amino acid sequence shown in SEQ ID NO: 200 (or a variant thereof);

[0912] (u) a HCVR comprising:

[0913] HCDR1 having the amino acid sequence shown in SEQ ID NO: 203 (or a variant thereof),

[0914] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 204 (or a variant thereof), and

[0915] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 205 (or a variant thereof); and

[0916] An LCVR, the LCVR containing:

[0917] LCDR1 having the amino acid sequence shown in SEQ ID NO: 208 (or a variant thereof),

[0918] LCDR2 having the amino acid sequence shown in SEQ ID NO: 209 (or a variant thereof), and

[0919] LCDR3 having the amino acid sequence shown in SEQ ID NO: 210 (or a variant thereof);

[0920] (v) a HCVR comprising:

[0921] HCDR1 having the amino acid sequence shown in SEQ ID NO: 213 (or a variant thereof),

[0922] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 214 (or a variant thereof), and

[0923] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 215 (or a variant thereof); and

[0924] An LCVR, the LCVR containing:

[0925] LCDR1 having the amino acid sequence shown in SEQ ID NO: 218 (or a variant thereof),

[0926] LCDR2 having the amino acid sequence shown in SEQ ID NO: 219 (or a variant thereof), and

[0927] LCDR3 having the amino acid sequence shown in SEQ ID NO: 220 (or a variant thereof);

[0928] (w) a HCVR comprising:

[0929] HCDR1 having the amino acid sequence shown in SEQ ID NO: 223 (or a variant thereof),

[0930] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 224 (or a variant thereof), and

[0931] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 225 (or a variant thereof); and

[0932] An LCVR, the LCVR containing:

[0933] LCDR1 having the amino acid sequence shown in SEQ ID NO: 228 (or a variant thereof),

[0934] LCDR2 having the amino acid sequence shown in SEQ ID NO: 229 (or a variant thereof), and

[0935] LCDR3 having the amino acid sequence shown in SEQ ID NO: 230 (or a variant thereof);

[0936] (x) a HCVR comprising:

[0937] HCDR1 having the amino acid sequence shown in SEQ ID NO: 233 (or a variant thereof),

[0938] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 234 (or a variant thereof), and

[0939] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 235 (or a variant thereof); and

[0940] An LCVR, the LCVR containing:

[0941] LCDR1 having the amino acid sequence shown in SEQ ID NO: 238 (or a variant thereof),

[0942] LCDR2 having the amino acid sequence shown in SEQ ID NO: 239 (or a variant thereof), and

[0943] LCDR3 having the amino acid sequence shown in SEQ ID NO: 240 (or a variant thereof);

[0944] (y) a HCVR comprising:

[0945] HCDR1 having the amino acid sequence shown in SEQ ID NO: 243 (or a variant thereof),

[0946] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 244 (or a variant thereof), and

[0947] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 245 (or a variant thereof); and

[0948] An LCVR, the LCVR containing:

[0949] LCDR1 having the amino acid sequence shown in SEQ ID NO: 248 (or a variant thereof),

[0950] LCDR2 having the amino acid sequence shown in SEQ ID NO: 249 (or a variant thereof), and

[0951] LCDR3 having the amino acid sequence shown in SEQ ID NO: 250 (or a variant thereof);

[0952] (z) a HCVR comprising:

[0953] HCDR1 having the amino acid sequence shown in SEQ ID NO: 253 (or a variant thereof),

[0954] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 254 (or a variant thereof), and

[0955] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 255 (or a variant thereof); and

[0956] An LCVR, the LCVR containing:

[0957] LCDR1 having the amino acid sequence shown in SEQ ID NO: 258 (or a variant thereof),

[0958] LCDR2 having the amino acid sequence shown in SEQ ID NO: 259 (or a variant thereof), and

[0959] A LCDR3 having the amino acid sequence shown in SEQ ID NO: 260 (or a variant thereof); (aa) a HCVR comprising:

[0960] HCDR1 having the amino acid sequence shown in SEQ ID NO: 263 (or a variant thereof),

[0961] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 264 (or a variant thereof), and

[0962] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 265 (or a variant thereof); and

[0963] An LCVR, the LCVR containing:

[0964] LCDR1 having the amino acid sequence shown in SEQ ID NO: 268 (or a variant thereof),

[0965] LCDR2 having the amino acid sequence shown in SEQ ID NO: 269 (or a variant thereof), and

[0966] A LCDR3 having the amino acid sequence shown in SEQ ID NO: 270 (or a variant thereof); (ab) a HCVR comprising:

[0967] HCDR1 having the amino acid sequence shown in SEQ ID NO: 273 (or a variant thereof),

[0968] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 274 (or a variant thereof), and

[0969] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 275 (or a variant thereof); and

[0970] An LCVR, the LCVR containing:

[0971] LCDR1 having the amino acid sequence shown in SEQ ID NO: 278 (or a variant thereof),

[0972] LCDR2 having the amino acid sequence shown in SEQ ID NO: 279 (or a variant thereof), and

[0973] LCDR3 having the amino acid sequence shown in SEQ ID NO: 280 (or a variant thereof);

[0974] (ac) a HCVR comprising:

[0975] HCDR1 having the amino acid sequence shown in SEQ ID NO: 283 (or a variant thereof),

[0976] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 284 (or a variant thereof), and

[0977] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 285 (or a variant thereof); and

[0978] An LCVR, the LCVR containing:

[0979] LCDR1 having the amino acid sequence shown in SEQ ID NO: 288 (or a variant thereof),

[0980] LCDR2 having the amino acid sequence shown in SEQ ID NO: 289 (or a variant thereof), and

[0981] LCDR3 having the amino acid sequence shown in SEQ ID NO: 290 (or a variant thereof);

[0982] (ad) a HCVR comprising:

[0983] HCDR1 having the amino acid sequence shown in SEQ ID NO: 293 (or a variant thereof),

[0984] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 294 (or a variant thereof), and

[0985] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 295 (or a variant thereof); and

[0986] An LCVR, the LCVR containing:

[0987] LCDR1 having the amino acid sequence shown in SEQ ID NO: 298 (or a variant thereof),

[0988] LCDR2 having the amino acid sequence shown in SEQ ID NO: 299 (or a variant thereof), and

[0989] LCDR3 having the amino acid sequence shown in SEQ ID NO: 300 (or a variant thereof);

[0990] (ae) a HCVR comprising:

[0991] HCDR1 having the amino acid sequence shown in SEQ ID NO: 303 (or a variant thereof),

[0992] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 304 (or a variant thereof), and

[0993] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 305 (or a variant thereof); and

[0994] An LCVR, the LCVR containing:

[0995] LCDR1 having the amino acid sequence shown in SEQ ID NO: 308 (or a variant thereof),

[0996] LCDR2 having the amino acid sequence shown in SEQ ID NO: 309 (or a variant thereof), and

[0997] LCDR3 having the amino acid sequence shown in SEQ ID NO: 310 (or a variant thereof);

[0998] and / or

[0999] (af) HCVR comprising:

[1000] HCDR1 having the amino acid sequence shown in SEQ ID NO: 313 (or a variant thereof),

[1001] a HCDR2 having the amino acid sequence shown in SEQ ID NO: 314 (or a variant thereof), and

[1002] a HCDR3 having the amino acid sequence shown in SEQ ID NO: 315 (or a variant thereof); and

[1003] An LCVR, the LCVR containing:

[1004] LCDR1 having the amino acid sequence shown in SEQ ID NO: 318 (or a variant thereof),

[1005] LCDR2 having the amino acid sequence shown in SEQ ID NO: 319 (or a variant thereof), and

[1006] a LCDR3 having the amino acid sequence shown in SEQ ID NO: 320 (or a variant thereof); or the scFv comprises:

[1007] (i) a HCVR having the amino acid sequence set forth in SEQ ID NO: 2 or 462 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 7 (or a variant thereof);

[1008] (ii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 12 or 463 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 17 (or a variant thereof);

[1009] (iii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 22 or 464 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 27 (or a variant thereof);

[1010] (iv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 32 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 37 or 465 (or a variant thereof);

[1011] (v) a HCVR having the amino acid sequence set forth in SEQ ID NO: 42 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 47 or 466 (or a variant thereof);

[1012] (vi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 52 or 467 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 57 or 468 (or a variant thereof);

[1013] (vii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 62 or 492 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 67 or 469 (or a variant thereof);

[1014] (viii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 72 or 470 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 77 or 471 (or a variant thereof);

[1015] (ix) a HCVR having the amino acid sequence set forth in SEQ ID NO: 82 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 87 (or a variant thereof);

[1016] (x) a HCVR having the amino acid sequence set forth in SEQ ID NO: 92 or 472 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 97 (or a variant thereof);

[1017] (xi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 102 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 107 (or a variant thereof);

[1018] (xii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 112 or 473 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 117 or 474 (or a variant thereof);

[1019] (xiii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 122 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 127 (or a variant thereof);

[1020] (xiv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 132 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 137 (or a variant thereof);

[1021] (xv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 142 or 475 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 147 or 476 (or a variant thereof);

[1022] (xvi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 152 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 157 (or a variant thereof);

[1023] (xvii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 162 or 477 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 167 (or a variant thereof);

[1024] (xviii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 172 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 177 (or a variant thereof);

[1025] (xix) a HCVR having the amino acid sequence set forth in SEQ ID NO: 182 or 478 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 187 or 479 (or a variant thereof);

[1026] (xx) a HCVR having the amino acid sequence set forth in SEQ ID NO: 192 or 480 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 197 (or a variant thereof);

[1027] (xxi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 202 or 481 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 207 (or a variant thereof);

[1028] (xxii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 212 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 217 (or a variant thereof);

[1029] (xxiii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 222 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 227 (or a variant thereof);

[1030] (xxiv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 232 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 237 (or a variant thereof);

[1031] (xxv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 242 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 247 (or a variant thereof);

[1032] (xxvi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 252 or 482 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 257 (or a variant thereof);

[1033] (xxvii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 262 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 267 (or a variant thereof);

[1034] (xxviii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 272 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 277 (or a variant thereof);

[1035] (xxix) a HCVR having the amino acid sequence set forth in SEQ ID NO: 282 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 287 (or a variant thereof);

[1036] (xxx) a HCVR having the amino acid sequence set forth in SEQ ID NO: 292 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 297 (or a variant thereof);

[1037] (xxxi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 302 or 483 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 307 or 527 (or a variant thereof); and / or

[1038] (xxxii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 312 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 317 or 484 (or a variant thereof);

[1039] For example, where the HCVR and LCVR are in either orientation (HCVR-LCVR or LCVR-HCVR),

[1040] Optionally, wherein the HCVR and LCVR are connected by a linker, e.g., comprising an amino acid sequence, e.g., about 10 amino acids in length, e.g., (Gly4Ser)n (SEQ ID NO: 426), wherein n is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[1041] In some embodiments, V L -(Gly4Ser)3(SEQ ID NO:541)-V H The anti-hTfR scFv described herein in the form of V comprises the amino acid sequence shown in Tables 1-2. In other embodiments, the scFv described herein can be V H -(Gly4Ser)3(SEQ ID NO:541)-V L Optionally, the anti-hTfR scFv described herein further comprises an N-terminal LLQGSG (SEQ ID NO: 452) and / or a C-terminal HHHHHH (SEQ ID NO: 501).

[1042] Table 1-2. Anti-hTfR scFv molecules in the protein-drug conjugates .

[1043]

[1044]

[1045]

[1046]

[1047]

[1048]

[1049]

[1050] Provided herein are Fab fragments that specifically bind to human transferrin receptor, optionally conjugated to a molecular cargo (anti-TfR Fab-drug conjugates). Fab fragments typically contain a complete light chain, VL, and a constant light chain domain, such as a kappa heavy chain (e.g., and VH and IgG1 CH1 portions, e.g.,

[1051] or IgG4 CH1 (e.g., or LGTKTYTCNVDHKPSNTKVDKRVESKYGPP (SEQ ID NO: 493). Fab fragment antibodies can be produced by papain digestion of whole IgG antibodies to remove the entire Fc fragment (including the hinge region). For example, the Fab protein described herein can comprise:

[1052] (1) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 2 or 462, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to a CH1 domain, and

[1053] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO:7, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1054] (2) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 12 or 463, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1055] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 17, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1056] (3) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 22 or 464, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1057] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 27, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1058] (4) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 32, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1059] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 37 or 465, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1060] (5) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 42, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1061] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 47 or 466, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1062] (6) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 52 or 467, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1063] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 57 or 468, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1064] (7) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 62 or 492, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1065] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 67 or 469, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1066] (8) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 72 or 470, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1067] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 77 or 471, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1068] (9) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 82, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1069] (10) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 92 or 472, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1070] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO:97, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1071] (11) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 102, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1072] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 107, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1073] (12) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 112 or 473, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1074] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 117 or 474, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1075] (13) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 122, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1076] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 127, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1077] (14) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 132, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1078] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 137, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1079] (15) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 142 or 475, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1080] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 147 or 476, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1081] (16) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 152, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1082] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 157, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1083] (17) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 162 or 477, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1084] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 167, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1085] (18) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 172, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1086] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 177, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1087] (19) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 182 or 478, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1088] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 187 or 479, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to a CL domain;

[1089] (20) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 192 or 480, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1090] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 197, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1091] (21) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 202 or 481, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1092] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 207, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1093] (22) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 212, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1094] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 217, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1095] (23) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 222, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being linked to the CH1 domain, and a light chain variable region (LCVR) having the amino acid sequence shown in SEQ ID NO: 227, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1096] (24) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 232, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1097] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 237, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1098] (25) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 242, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1099] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 247, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1100] (26) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 252 or 482, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1101] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 257, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1102] (27) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 262, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1103] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 267, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1104] (28) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 272, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1105] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 277, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1106] (29) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 282, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1107] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 287, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1108] (30) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 292, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1109] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 297, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1110] (31) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 302 or 483, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1111] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 307 or 527, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain; and / or

[1112] (32) a heavy chain variable region (HCVR) having the amino acid sequence shown in SEQ ID NO: 312, or a heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, such HCVR being connected to the CH1 domain, and

[1113] a light chain variable region (LCVR) having the amino acid sequence set forth in SEQ ID NO: 317 or 484, or a light chain variable region comprising LCDR1, LCDR2, and LCDR3, such LCVR being linked to the CL domain;

[1114] For example, wherein CH1 is derived from IgG1 or IgG4;

[1115] For example, wherein CH1 is SEQ ID NO: 425, 459 or 493.

[1116] The heavy and light chains of the anti-hTfR Fab in the anti-hTfR protein-drug conjugates described herein are shown below.

[1117] (1)31874B

[1118] Fab light chain

[1119]

[1120] Fab heavy chain

[1121]

[1122] (2)31863B

[1123] Fab light chain

[1124]

[1125] Fab heavy chain

[1126]

[1127] (3)69348

[1129] Fab light chain

[1130]

[1131] Fab heavy chain

[1132] (4)69340

[1134] Fab light chain

[1135]

[1136] Fab heavy chain

[1137] (5)69331

[1139] Fab light chain

[1140]

[1141] Fab heavy chain

[1142]

[1143] (6)69332

[1145] Fab light chain

[1146]

[1147] Fab heavy chain

[1148] (7)69326

[1150] Fab light chain

[1151]

[1152] Fab heavy chain

[1153] (8)69329

[1155] Fab light chain

[1156]

[1157] Fab heavy chain

[1158]

[1159] (9)69323

[1161] Fab light chain

[1162]

[1163] Fab heavy chain

[1164] (10)69305

[1166] Fab light chain

[1167]

[1168] Fab heavy chain

[1169] (11)69307

[1171] Fab light chain

[1172]

[1173] Fab heavy chain

[1174]

[1175]

[1176] (12)12795B

[1177] Fab light chain

[1178]

[1179] Fab heavy chain

[1180]

[1181] (13)12798B

[1182] Fab light chain

[1183]

[1184] Fab heavy chain

[1185]

[1186] or

[1187]

[1188] (14)12799B

[1189] Fab light chain

[1190]

[1191] Fab heavy chain

[1192] or

[1193]

[1194] (15)12801B

[1195] Fab light chain

[1196]

[1197] Fab heavy chain

[1198]

[1199] (16)12802B

[1200] Fab light chain

[1201]

[1202] Fab heavy chain

[1203]

[1204] (17)12808B

[1205] Fab light chain

[1206]

[1207] Fab heavy chain

[1208]

[1209] (18)12812B

[1210] Fab light chain

[1211]

[1212] Fab heavy chain

[1213]

[1214] (19)12816B

[1215] Fab light chain

[1216]

[1217] Fab heavy chain

[1218]

[1219] (20)12833B

[1220] Fab light chain

[1221]

[1222] Fab heavy chain

[1223]

[1224] (21)12834B

[1225] Fab light chain

[1226]

[1227] Fab heavy chain

[1228]

[1229] (22)12835B

[1230] Fab light chain

[1231]

[1232] Fab heavy chain

[1233]

[1234] (23)12847B

[1235] Fab light chain

[1236]

[1237] Fab heavy chain

[1238] or

[1239]

[1240] (24)12848B

[1241] Fab light chain

[1242]

[1243] Fab heavy chain

[1244]

[1245]

[1246] (25)12843B

[1247] Fab light chain

[1248]

[1249] Fab heavy chain

[1250] or

[1251]

[1252] (26)12844B

[1253] Fab light chain

[1254]

[1255] Fab heavy chain

[1256]

[1257] (27)12845B

[1258] Fab light chain

[1259]

[1260] Fab heavy chain

[1261] or

[1262]

[1263] (28)12839B

[1264] Fab light chain

[1265]

[1266] Fab heavy chain

[1267]

[1268] (SEQ ID NO: 490)

[1269]

[1270] (29)12841B

[1271] Fab light chain

[1272]

[1273] Fab heavy chain

[1274]

[1275] (30)12850B

[1276] Fab light chain

[1277]

[1278] Fab heavy chain

[1279] (31)69261

[1281] Fab light chain

[1282]

[1283] Fab heavy chain

[1284] (32)69263

[1286] Fab light chain

[1287]

[1288] Fab heavy chain

[1289]

[1290] In some embodiments, an anti-hTfR protein described herein can comprise any of the exemplary hIgG1 heavy chain sequences provided in Tables 1-3.

[1291] Table 1-3. hIgG1 heavy chain sequence

[1292]

[1293]

[1294]

[1295]

[1296]

[1297]

[1298]

[1299]

[1300]

[1301]

[1302]

[1303] In some embodiments, the anti-TfR proteins described herein may comprise an IgG1 heavy chain constant domain comprising

[1304] amino acid sequence or a variant thereof.

[1305] "31874B", "31863B", "69348", "69340", "69331", "69332", "69326", "69329", "69323", "69305", "69307", "12795B", "12798B", "12799B", "12801B", "12802B", "12808B", "12812B", "12816B", "12833B", "12834B", "12835B", "12847B", "12848B", "12843B", "12844B", "12845B", "12839B", "12841B", "12850B", "69261" and "69263" refer to anti-TfR protein-drug conjugates, such as anti-TfR scFv or anti-TfR Fab comprising: a light chain variable region having an amino acid sequence as set forth in SEQ ID NO: 7, 17, 27, 37, 465, 47, 466, 57, 468, 67, 469, 77, 471, 87, 97, 107, 117, 474, 127, 137, 147, 476, 157, 167, 177, 187, 479, 197, 207, 217, 227, 237, 247, 257, 267, 277, 287, 297, 307, 527, 317 or 484 (or a variant thereof), and a light chain variable region having an amino acid sequence as set forth in SEQ ID NO: 7, 17, 27, 37, 465, 47, 466, 57, 468, 67, 469, 77, 471, 87, 97, 107, 117, 474, 127, 137, 147, 476, 157, 167, 177, 187, 479, 197, NO: 2, 462, 12, 463, 22, 464, 32, 42, 52, 467, 62, 492, 72, 470, 82, 92, 472, 102, 112, 473, 122, 132, 142, 475, 152, 162, 477, 172, 182, 478, 192, 480, 202, 481, 212, 222, 232, 242, 252, 482, 262, 272, 282, 292, 302, 483 or 312 amino acid sequence (or variants thereof), which in the case of scFv can be, for example, linked by a peptide linker (e.g., (G4S)3 (SEQ ID NO: 2), respectively. No: 541)) fused together (in any order); or comprising: V containing its CDRs (CDR-H1 (or its variant), CDR-H2 (or its variant) and CDR-H3 (or its variant)) H and / or V comprising its CDRs (CDR-L1 (or variants thereof), CDR-L2 (or variants thereof) and CDR-L3 (or variants thereof)) L , which in the case of scFv, is related to V L Fusion V H or with V H Fusion V LConjugation to the molecular cargo can be achieved, for example, via a linker.

[1306] The term "fused" or "tethered" with reference to a fusion polypeptide refers to polypeptides that are directly or indirectly linked (eg, via a linker or another polypeptide).

[1307] In some embodiments, the anti-TfR antigen binding proteins described herein include humanized antibodies or antigen binding fragments thereof, murine antibodies or antigen binding fragments thereof, chimeric antibodies or antigen binding fragments thereof, monoclonal antibodies or antigen binding fragments thereof (e.g., monovalent Fab', bivalent Fab2, F(ab)'3 fragments, single-chain variable fragments (scFv), dual scFv, (scFv)2, double-chain antibodies, bivalent antibodies, one-armed antibodies, miniantibodies, nanoantibodies, three-chain antibodies, four-chain antibodies, disulfide-stabilized Fv proteins (dsFv), single domain antibodies (sdAb), Ig NARs, camel antibodies or antigen binding fragments thereof, bispecific antibodies or binding fragments thereof (e.g., dual scFv, or bispecific T cell engagers (BiTE)), trispecific antibodies (e.g., F(ab)'3 fragments or three-chain antibodies), or chemically modified derivatives thereof.

[1308] As used herein, the term "humanized antibodies" includes antibodies in which CDR sequences derived from the germline of another mammalian species, such as a mouse, have been grafted onto human framework sequences or otherwise modified to increase their similarity to naturally occurring antibody variants in humans.

[1309] In some cases, the anti-TfR antigen binding protein is an antibody comprising one or more mutations in the framework region (e.g., in a CH1 domain, a CH2 domain, a CH3 domain, a hinge region, or a combination thereof). In some embodiments, the one or more mutations will be used to stabilize the antibody and / or increase half-life. In some embodiments, the one or more mutations are used to modulate Fc receptor interactions, reduce or eliminate Fc effector functions, such as FcγR, antibody-dependent cell-mediated cytotoxicity (ADCC), or complement-dependent cytotoxicity (CDC). In further embodiments, the one or more mutations will be used to modulate glycosylation.

[1310] In some embodiments, one, two, or more mutations (e.g., amino acid substitutions) are introduced into the Fc region of an antibody described herein (e.g., in the CH2 domain (residues 231-340 of human IgG1) and / or the CH3 domain (residues 341-447 of human IgG1) and / or the hinge region, wherein numbering is according to the Kabat numbering system (e.g., the EU index in Kabat)) to alter one or more functional properties of the antibody, such as serum half-life, complement fixation, Fc receptor binding, and / or antigen-dependent cellular cytotoxicity. In some embodiments, one, two, or more mutations (e.g., amino acid substitutions) are introduced into the hinge region of the Fc region (CH1 domain) such that the number of cysteine ​​residues in the hinge region is altered (e.g., increased or decreased), as described, e.g., in U.S. Pat. No. 5,677,425. The number of cysteine ​​residues in the hinge region of the CH1 domain can be altered, for example, to facilitate assembly of the light and heavy chains, or to alter (eg, increase or decrease) antibody stability, or to facilitate linker conjugation.

[1311] In some embodiments, one, two or more amino acid mutations (i.e., substitutions, insertions or deletions) are introduced into IgG constant domains or their FcRn binding fragments (preferably Fc or hinge-Fc domain fragments) to change (e.g., shorten or extend) the half-life of the antibody in vivo. See, for example, PCT Publications WO 02 / 060919, WO 98 / 23289 and WO 97 / 34631, and U.S. Patents 5,869,046, 6,121,022, 6,277,375 and 6,165,745 for examples of mutations that change (e.g., shorten or extend) the half-life of the antibody in vivo. In some embodiments, the Fc region comprises a mutation at residue positions L234, L235 or a combination thereof. In some embodiments, the mutation comprises L234 and L235. In some embodiments, the mutation comprises L234A and L235A.

[1312] The anti-TfR antibodies and antigen-binding fragments described herein can be post-translationally modified, such as by glycosylation.

[1313] For example, the antibodies and antigen-binding fragments described herein can be glycosylated (e.g., N-glycosylated and / or O-glycosylated), or non-glycosylated. Typically, antibodies and antigen-binding fragments are glycosylated at the conserved residue N297 of the IgG Fc domain. Some antibodies and fragments contain one or more additional glycosylation sites in the variable region. In one embodiment, the glycosylation site is in the following context: FN 297 S or YN 297 S.

[1314] In one embodiment, the glycosylation is any one or more of the three different N-glycan types: high mannose, complex, and / or hybrid, which are found on IgG and have corresponding linkages. Complex and hybrid types exist with core fucosylation, addition of fucose residues to the innermost N-acetylglucosamine, and no core fucosylation.

[1315] In some cases, the anti-TfR antigen binding protein is an aglycosylated antibody, i.e., an antibody that does not comprise a glycosylation sequence that may interfere with a transglutamination reaction, such as an antibody that does not have a sugar group at N297 (or with reference to position N180 of the amino acid sequence of SEQ ID NO: 575) on one or more heavy chains according to the EU numbering system. In a specific embodiment, the antibody heavy chain has an N297 mutation (or with reference to position N180 of the amino acid sequence of SEQ ID NO: 575). In a specific embodiment, the antibody heavy chain has an N297Q or N297D mutation (or with reference to N180Q or N180D mutation of the amino acid sequence of SEQ ID NO: 575). The N-linked glycans found at position 297 can be found as a core structure that is common to all IgG found in humans and rodents. Antibodies containing such mutations can be prepared by removing or invalidating the glycosylation sequence by site-directed mutagenesis, or by inserting glutamine residues at sites other than any interfering glycosylation sites or any other interfering structures by site-directed mutagenesis. Such antibodies can also be isolated from natural or artificial sources. Aglycosylated antibodies also include antibodies containing T299, S298P or other mutations, or combinations of mutations that result in a lack of glycosylation.

[1316] In some cases, the antigen binding protein is a deglycosylated antibody, i.e., an antibody in which sugar groups are removed to facilitate transglutaminase-mediated conjugation. Carbohydrates include, but are not limited to, N-linked oligosaccharides. In some embodiments, deglycosylation is performed at residue N180 (with reference to the amino acid sequence of SEQ ID NO: 575). In some embodiments, deglycosylation is performed at residue N297 according to the EU numbering system. In some embodiments, removal of sugar groups is enzymatically accomplished, including but not limited to via PNGase.

[1317] In one embodiment, the antibodies or fragments described herein are afucosylated.

[1318] The antibodies and antigen-binding fragments described herein can also be post-translationally modified in other ways, including, for example: Glu or Gln cyclization at the N-terminus, loss of the N-terminal positive charge, Lys variants at the C-terminus, deamidation (from Asn to Asp), isomerization (from Asp to isoAsp), deamidation (from Gln to Glu), oxidation (Cys, His, Met, Tyr, Trp), and / or disulfide bond heterogeneity (shuffling, thioether and trisulfide formation).

[1319] In some embodiments, the antibodies disclosed herein comprise Q295, which may be native to the antibody heavy chain sequence. In some embodiments, the antibody heavy chain disclosed herein may comprise Q295. In some embodiments, the antibody heavy chain disclosed herein may comprise Q295 and the amino acid substitution N297D.

[1320] According to certain embodiments of the present disclosure, anti-TfR antibodies and antigen-binding fragments comprising the following Fc domain are provided: the Fc domain comprises one or more mutations that enhance or weaken the binding of the antibody to the FcRn receptor (e.g., at acidic pH compared to neutral pH). For example, the present disclosure includes anti-TfR antibodies having a mutation in the CH2 or CH3 region of the Fc domain, wherein the mutation increases the affinity of the Fc domain for FcRn in an acidic environment (e.g., in endosomes with a pH range of about 5.5 to about 6.0). When administered to an animal, such mutations can cause an increase in the serum half-life of the antibody.

[1321] Non-limiting examples of such Fc modifications include, for example, modifications at the following positions:

[1322] 250 (e.g., E or Q),

[1323] 250 and 428 (e.g., L or F),

[1324] 252 (e.g., L / Y / F / W or T),

[1325] 254 (e.g., S or T), and / or

[1326] 256 (e.g., S / R / Q / E / D or T);

[1327] and / or modifications at the following locations:

[1328] 428 and / or 433 (e.g., H / L / R / S / P / Q or K), and / or

[1329] 434 (e.g., A, W, H, F, or Y);

[1330] and / or modifications at the following locations:

[1331] 250 and / or 428;

[1332] and / or modifications at the following locations:

[1333] ·307 or 308 (e.g., 308F, V308F), and / or 434.

[1334] In one embodiment, the modification comprises:

[1335] 428L (e.g., M428L) and 434S (e.g., N434S) modifications;

[1336] 428L, 259I (e.g., V259I), and 308F (e.g., V308F) modifications;

[1337] 433K (e.g., H433K) and 434 (e.g., 434Y) modifications;

[1338] 252, 254, and 256 (e.g., 252Y, 254T, and 256E) modifications;

[1339] 250Q and 428L modifications (e.g., T250Q and M428L); and / or

[1340] 307 and / or 308 modifications (e.g., 308F or 308P).

[1341] For example, the present disclosure includes anti-TfR antibodies having an Fc domain comprising one or more pairs or groups of mutations selected from the group consisting of:

[1342] 250Q and 248L (e.g., T250Q and M248L);

[1343] 252Y, 254T, and 256E (e.g., M252Y, S254T, and T256E);

[1344] 257I and 311I (e.g., P257I and Q311I);

[1345] 257I and 434H (e.g., P257I and N434H);

[1346] 376V and 434H (for example, D376V and N434H);

[1347] 307A, 380A, and 434A (e.g., T307A, E380A, and N434A);

[1348] 428L and 434S (e.g., M428L and N434S); and

[1349] 433K and 434F (e.g., H433K and N434F).

[1350] In yet another embodiment, the modification includes a 265A (eg, D265A) and / or a 297A (eg, N297A) modification.

[1351] In one embodiment, the heavy chain constant domain is γ4 comprising S228P and / or S108P mutations. See Angal et al., A single amino acid substitution abolizes the heterogeneity of chimeric mouse / human (IgG4) antibody, Mol Immunol. 1993 Jan; 30(1): 105-108.

[1352] All possible combinations of the foregoing Fc domain mutations and other mutations within the antibody variable domains disclosed herein are contemplated to be within the scope of the present disclosure.

[1353] The anti-TfR antibodies described herein may comprise a modified Fc domain with reduced effector function. As used herein, a “modified Fc domain with reduced effector function” means that any Fc portion of an immunoglobulin has been modified, mutated, truncated, etc. relative to a wild-type naturally occurring Fc domain, such that the molecule comprising the modified Fc exhibits a reduced severity or degree of at least one effect selected from the group consisting of: cell killing (e.g., ADCC and / or CDC), complement activation, phagocytosis, and opsonization relative to a comparison molecule comprising a wild-type naturally occurring Fc portion. In certain embodiments, a “modified Fc domain with reduced effector function” is an Fc domain that has reduced or attenuated binding to an Fc receptor (e.g., FcγR).

[1354] In certain embodiments, the modified Fc domain is a variant IgG1 Fc or variant IgG4 Fc comprising a substitution in the hinge region. For example, the modified Fc used in the context of the present disclosure may include a variant IgG1 Fc in which at least one amino acid in the IgG1 Fc hinge region is replaced by a corresponding amino acid from an IgG2 Fc hinge region. Alternatively, the modified Fc used in the context of the present disclosure may include a variant IgG4 Fc in which at least one amino acid in the IgG4 Fc hinge region is replaced by a corresponding amino acid from an IgG2 Fc hinge region. Non-limiting exemplary modified Fc regions that can be used in the context of the present disclosure are described in U.S. Patent Application Publication No. 2014 / 0243504, the disclosure of which and any functionally equivalent variants of the modified Fc regions described therein are hereby incorporated by reference in their entirety.

[1355] The present disclosure also includes antigen-binding proteins, antibodies or antigen-binding fragments, which include HCVR shown herein and chimeric heavy chain constant (CH) region, wherein the chimeric CH region includes a segment derived from the CH region of more than one immunoglobulin isotype. For example, the antibody of the present disclosure may include a chimeric CH region, which includes a portion or all of the CH2 domains derived from human IgG1, human IgG2 or human IgG4 molecules, and a portion or all of the CH3 domains derived from human IgG1, human IgG2 or human IgG4 molecules combined therewith. According to certain embodiments, the antibody of the present disclosure includes a chimeric CH region with a chimeric hinge region. For example, a chimeric hinge can include an "upper hinge" amino acid sequence (according to EU numbering from position 216 to 227 amino acid residues) derived from human IgG1, human IgG2 or human IgG4 hinge region, and a "lower hinge" sequence (according to EU numbering from position 228 to 236 amino acid residues) derived from human IgG1, human IgG2 or human IgG4 hinge region combined therewith. According to certain embodiments, the chimeric hinge region comprises amino acid residues derived from the upper hinge of human IgG1 or human IgG4 and amino acid residues derived from the lower hinge of human IgG2. In certain embodiments, antibodies comprising a chimeric CH region as described herein can exhibit modified Fc effector functions without adversely affecting the therapeutic or pharmacokinetic properties of the antibody. (See, for example, WO2014 / 022540).

[1356] Other modified Fc domains and Fc modifications that can be used in the context of the present disclosure include any of the modifications described in US2014 / 0171623, US8,697,396, US2014 / 0134162, WO2014 / 043361, the disclosures of which are hereby incorporated by reference in their entirety. Methods for constructing antibodies or other antigen-binding fusion proteins comprising modified Fc domains as described herein are known in the art.

[1357] In some embodiments, the anti-TfR antibodies and antigen-binding fragments described herein comprise an Fc domain comprising one or more mutations in the CH2 region and / or the CH3 region that generate separate TfR binding sites.

[1358] In one embodiment, the CH2 region comprises one or more amino acid mutations selected from the following, or a combination thereof: a) position 47 is Glu, Gly, Gln, Ser, Ala, Asn, Tyr or Trp; position 49 is Ile, Val, Asp, Glu, Thr, Ala or Tyr; position 56 is Asp, Pro, Met, Leu, Ala, Asn or Phe; position 58 is Arg, Ser, Ala or Gly; position 59 is Tyr, Trp, Arg or Val; position 60 is Glu; position 61 is Trp or Tyr; position 62 is Gln, Tyr, His, Ile, Phe, Val or Asp; position 63 is Leu, Trp, Arg, Asn, Tyr or Val; b) position 39 is Pro, Phe, Ala, Met or Asp; position 40 is Gln, Pro, Arg, Lys, Ala, Ile, Leu, Glu, Asp or Tyr; position 41 is Thr, Ser, Gly, Met, Val, Phe, Trp or Leu; position 42 is Pro, Val, Ala, Thr or Asp; position 43 is Pro, Val or Phe; position 44 is Trp, Gln, Thr or Glu; Position 68 is Glu, Val, Thr, Leu or Trp; Position 70 is Tyr, His, Val or Asp; Position 71 is Thr, His, Gln, Arg, Asn or Val; Position 72 is Tyr, Asn, Asp, Ser or Pro; c) Position 41 is Val or Asp; Position 42 is Pro, Met or Asp; Position 43 is Pro or Trp; Position 44 is Arg, Trp, Glu or Thr; Position 45 is Met, Tyr or Trp; Position 65 is Leu or Trp; Position 66 is Thr, Val, Ile or Lys; Position 67 is Ser, Lys, Ala or Leu; position 69 is His, Leu or Pro; position 73 is Val or Trp; or d) position 45 is Trp, Val, Ile or Ala; position 47 is Trp or Gly; position 49 is Tyr, Arg or Glu; position 95 is Ser, Arg or Gln; position 97 is Val, Ser or Phe; position 99 is Ile, Ser or Trp; position 102 is Trp, Thr, Ser, Arg or Asp; position 103 is Trp; position 104 is Ser, Lys, Arg or Val; wherein the substitutions and positions are referenced

[1359] Amino acids 4-113 were identified.

[1360] In one embodiment, the CH3 region comprises one or more amino acid mutations selected from the group consisting of: position 153 is Trp, Leu, or Glu; position 157 is Tyr or Phe; position 159 is Thr; position 160 is Glu; position 161 is Trp; position 162 is Ser, Ala, Val, or Asn; position 163 is Ser or Asn; position 186 is Thr or Ser; position 188 is Glu or Ser; position 189 is Glu; position 194 is Phe; or b) position 118 is Phe or Ile; position 119 is Asp, Glu, Gly, Ala, or Lys; position 120 is Tyr, Met, Leu, Ile, or Asp; position 122 is Thr or Ala; position 210 is Gly; position 211 is Phe; position 212 is His, Tyr, Ser, or Phe; position 213 is Asp; wherein the substitutions and positions are with reference to SEQ ID NO: 1. IDNO: 540 identified by amino acids 114-220.

[1361] In some embodiments, the CH3 region comprises one or more mutations selected from the following, or a combination thereof: according to EU numbering, position 384 is Leu, Tyr, Met or Val; position 386 is Leu, Thr, His or Pro; position 387 is Val, Pro or an acidic amino acid; position 388 is Trp; position 389 is Val, Ser or Ala; position 413 is Glu, Ala, Ser, Leu, Thr or Pro; position 416 is Thr or an acidic amino acid; position 421 is Trp, Tyr, His or Phe. In one embodiment, the CH3 region comprises one or more amino acid mutations selected from the following, or a combination thereof: according to EU numbering, position 380 is Trp, Leu or Glu; position 384 is Tyr or Phe; position 386 is Thr; position 387 is Glu; position 388 is Trp; position 389 is Ser, Ala, Val or Asn; position 390 is Ser or Asn; position 413 is Thr or Ser; position 415 is Glu or Ser; position 416 is Glu; and position 421 is Phe.

[1362] In some embodiments, the CH3 region comprises one or more mutations selected from the group consisting of: a) Phe at position 382, ​​Tyr at position 383, Asp at position 384, Asp at position 385, Ser at position 386, Lys at position 387, Leu at position 388, Thr at position 389, Pro at position 419, Arg at position 420, Gly at position 421, Leu at position 422, Ala at position 424, Glu at position 426, Tyr at position 438, Leu at position 440, or a combination thereof. 442, and Glu at position 443; b) Phe at position 382, ​​Tyr at position 383, Gly at position 384, N at position 385, Ala at position 386, Lys at position 387, Thr at position 389, Leu at position 422, Ala at position 424, Glu at position 426, Tyr at position 438, Leu at position 440; c) Phe at position 382, ​​Tyr at position 383, Glu at position 384, Ala at position 385, Lys at position 387, 424, Glu at position 426, Tyr at position 438, Leu at position 440; d) Phe at position 382, ​​Glu at position 384, Ser at position 386, Lys at position 387, Thr at position 389, Leu at position 422, Ala at position 424, Glu at position 426, Tyr at position 438, Leu at position 440; e) Phe at position 382, ​​Gly at position 384, Ala at position 385, Ser at position 386, Lys at position 387, Thr at position 389, Leu at position 422, Ala at position 424, Glu at position 426, Tyr at position 438, Leu at position 440; f) Phe at position 382, ​​Gly at position 384, Ala at position 385, Lys at position 387, Leu at position 388, Thr at position 389, Leu at position 422, Ala at position 424, Glu at position 426, Tyr at position 438, Leu at position 440; wherein the positions are determined according to EU numbering.

[1363] Additional mutations in the CH2 and / or CH3 regions that can introduce non-native TfR binding sites into the antigen binding proteins described herein include those described in U.S. Patent Application Publication Nos. 2020 / 0223935, 2020 / 0369746, 2021 / 0130485, 2022 / 0017634, and PCT Application Publication Nos. WO2023 / 279099, WO2023 / 114499, and WO2023 / 114510, which are incorporated herein by reference in their entirety.

[1364] Also provided herein is a container (e.g., a plastic or glass vial, e.g., with a cap or a chromatography column, a hollow bore needle, or a syringe barrel) comprising an anti-TfR protein-drug conjugate described herein, e.g., an anti-TfR scFv-drug conjugate or an anti-TfR Fab-drug conjugates, e.g., 31874B, 31863B, 69348, 69340, 69331, 69332, 69326, 69329, 69323, 69305, 69307, 12795B, 12798B, 12799B, 12801B, 12802B, 12808B, 12812B, 12816B, 12833B, 12834B, 12835B, 12847B, 12848B, 12843B, 12844B, 12845B, 12839B, 12841B, 12850B, 69261, and 69263.

[1365] Also provided herein is an injection device comprising the anti-TfR protein-drug conjugate described herein, such as the anti-TfR scFv drug conjugate or anti-TfRFab drug conjugate, such as 31874B, 31863B, 69348, 69340, 69331, 69332, 69326, 69329, 69323, 69305, 69307, 12795B, 12798B, 12799B, 12801B, 12802B, 12808B, 12812B, 12816B, 12833B, 12834B, 12835B, 12847B, 12848B, 12843B, 12844B, 12845B, 12839B, 12841B, 12850B, 69261 or 69263, or a pharmaceutical composition thereof. The injection device can be packaged into a kit. An injection device is a device for introducing a substance into a subject via a parenteral route, such as intramuscularly, subcutaneously, or intravenously. For example, an injection device can be a syringe (e.g., prefilled with a pharmaceutical composition, such as an autoinjector), which comprises, for example: a barrel or a needle for containing a fluid to be injected (e.g., containing a protein-drug conjugate or a pharmaceutical composition thereof), a needle for piercing the skin and / or a blood vessel or other tissue to inject the fluid; and a plunger for pushing the fluid out of the barrel and through the needle hole and into the subject's body.

[1366] Also provided herein are methods for administering to a subject an anti-TfR protein-drug conjugate described herein, such as an anti-TfRscFv-drug conjugate or an anti-TfRFab-drug conjugate, such as 31874B, 31863B, 69348, 69340, 69331, 69332, 69326, 69329, 69323, 69305, 69307, 12795B, 12798B, 12799B, 12801B, 128 02B, 12808B, 12812B, 12816B, 12833B, 12834B, 12835B, 12847B, 12848B, 12843B, 12844B, 12845B, 12839B, 12841B, 12850B, 69261 or 69263, the method comprising introducing the protein-drug conjugate into a subject (e.g., a human) parenterally (e.g., intravenously). For example, the method comprises piercing the subject's body with a needle of a syringe and then injecting the antigen-binding protein into the subject's body, e.g., into a vein, artery, tumor, muscle tissue or subcutaneous tissue of the subject.

[1367] Also provided herein are methods for delivering a molecular cargo to a target tissue in a subject, wherein the molecular cargo is conjugated to, for example, an antigen binding protein described herein, for example, an anti-TfR scFv anti-TfR described herein. Fab, e.g., 31874B, 31863B, 69348, 69340, 69331, 69332, 69326, 69329, 69323, 69305, 69307, 12795B, 12798B, 12799B, 12801B, 12802B, 12808B, 12812B, 12816B, 12833B, 12834B, 12835B, 12847B, 12848B, 12843B, 12844B, 12845B, 12839B, 12841B, 12850B, 69261, or 69263, wherein the target tissue is, e.g., any of the tissues or cells shown in Tables 1-4 below. The method further comprises introducing the protein-drug conjugate into a subject (e.g., a human) by, for example, parenteral administration (e.g., intravenously). For example, the method comprises piercing the subject's body with a needle of a syringe and then injecting the protein-drug conjugate into the subject, for example, into a vein, artery, tumor, muscle tissue, or subcutaneous tissue of the subject. For example, the protein-drug conjugate can be introduced into the subject via intrathecal, intracerebroventricular, or intraparenchymal injection into the central nervous system.

[1368] Table 1-4. Tissues and cells that can be targeted for delivery of molecular cargo using the anti-TfR antigen binding proteins. Cell type .

[1369]

[1370]

[1371]

[1372]

[1373]

[1374] Molecular cargo

[1375] In some aspects, the present disclosure includes methods and compositions for delivering a conjugated molecular cargo to a cell or tissue. In some aspects, an antigen binding protein disclosed herein that specifically binds to a transferrin receptor (TfR), such as an scFv, an antibody, or an antigen binding fragment thereof, can be conjugated (e.g., covalently conjugated) to a molecular cargo.

[1376] As used herein, the term "molecular cargo" refers to a molecule that acts to achieve a biological result. As a non-limiting example, the molecular cargo can be used to regulate the transcription of a dna sequence, the expression of a regulatory protein, or the activity of a regulatory protein, to delete or destroy an endogenous gene (or its fragment), to insert an exogenous gene (or its fragment), or to substitute an endogenous gene (or its fragment) with an exogenous gene (or its fragment). In various embodiments, the molecular cargo can comprise a polynucleotide. In various embodiments, the molecular cargo comprises lipid nanoparticles, liposomes, or non-lipid nanoparticles as described herein, and the molecular cargo optionally comprises one or more polynucleotides and / or protein molecules. In various embodiments, the molecular cargo can comprise a small molecule.

[1377] In some embodiments, the anti-TfR antibodies or antigen-binding fragments thereof disclosed herein can be used, for example, to deliver conjugated molecular cargoes to cells or tissues expressing TfR1 (e.g., brain or muscle) for diagnosis and / or treatment of diseases (e.g., neurological diseases or muscle diseases). In some embodiments, molecular cargoes conjugated to anti-TfR antibodies or antigen-binding fragments thereof can be taken up by, for example, endothelial cells via binding to transferrin receptors, which can be internalized, for example, via clathrin-mediated endocytosis. In some embodiments, the anti-TfR antibodies or antigen-binding fragments thereof described herein can, for example, exhibit excellent activity in delivering molecular cargoes to target tissues (e.g., brain, spinal cord, muscle, spleen, heart, or lungs) or target cells (e.g., brain cells or muscle cells). In some embodiments, the anti-TfR antibody or antigen-binding fragment thereof can effectively deliver a molecular cargo to one or more brain cells, such as neurons (e.g., motor neurons, sensory neurons), astrocytes, glial cells (e.g., oligodendrocytes, microglia), and / or other cells in the brain and / or spinal cord.

[1378] In some embodiments, molecular payload comprises polynucleotide molecule.Term " polynucleotide " and " nucleic acid " are used interchangeably in this article, refer to the polymer compound comprising nucleoside or nucleoside analog, and this nucleoside or nucleoside analog have nitrogenous heterocyclic base or base analog that are linked together along the backbone, including conventional RNA, DNA, mixed RNA-DNA and as its analog polymer.Nucleic acid " backbone " can be made up of a variety of keys, comprise one or more of following items: sugar-phosphodiester bond, peptide-nucleic acid bond (" peptide nucleic acid " or PNA; PCT No. WO 95 / 32305), phosphorothioate bond, methylphosphonate bond or their combination.The sugar part of nucleic acid can be ribose, deoxyribose or similar compound with optional substituent (for example, methoxyl group or 2 ' halide substituent).In some embodiments, the polynucleotide of about 30 nucleotides in length at most can be referred to as " oligonucleotide " in this article.Oligonucleotide can have a variety of different lengths, for example, depending on form. In some embodiments, the oligonucleotide is 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or more nucleotides in length. In some embodiments, the oligonucleotide is 8 to 30 nucleotides in length, 10 to 15 nucleotides in length, 10 to 20 nucleotides in length, 15 to 25 nucleotides in length, or 21 to 23 nucleotides in length.

[1379] In some embodiments, the molecular cargo described herein can include a carrier, such as a liposome or a lipid nanoparticle (LNP). Lipid particles, such as liposomes or lipid nanoparticles disclosed herein, can include lipid formulations that can be used to deliver therapeutic nucleic acids (e.g., gRNA) to target sites of interest (e.g., cells, tissues, organs, etc.). Without wishing to be bound by theory, carriers can be used as, for example, a means for delivering polynucleotides disclosed herein and / or proteins disclosed herein. In some embodiments, carriers (e.g., liposomes or LNPs) can be used for delivering nucleic acids (e.g., DNA or RNA), proteins (e.g., RNA-guided DNA binding agents) or combinations thereof. By way of non-limiting example, carriers (e.g., liposomes or LNPs) can be used for delivering various components of gene editing systems (e.g., CRISPR / Cas systems or other gene editing systems described herein).

[1380] In some embodiments, the molecular cargo comprises a small molecule. Small molecules (SM) can easily enter cells because they have a low molecular weight (generally, up to about 1 kDa). Once inside the cell, it can affect other molecules, such as proteins, and can, for example, cause cancer cell death. This is different from many large molecular weight molecules such as antibodies. Examples of small molecules that can be conjugated to anti-TfR antigen binding proteins to form anti-TfR:SM conjugates. In addition, anti-cancer SMs can be delivered by anti-TfR-mediated delivery. Such anti-cancer SMs can include, for example, cytotoxic agents, alkylating agents (e.g., platinum-containing drugs), antimetabolites (5-fluorouracil), topoisomerases (e.g., topotecan), anthracyclines (e.g., doxorubicin) and plant alkaloids (e.g., vinblastine). Other small molecule cargoes can include Miglustat.

[1381] Exemplary molecular cargoes are described in further detail herein, however, it should be understood that the exemplary molecular cargoes provided herein are not intended to be limiting.

[1382] polynucleotide molecules

[1383] Non-limiting examples of polynucleotide molecules that can be used as molecular cargos in the protein-drug conjugates described herein include, but are not limited to, interfering nucleic acids (e.g., shRNA, siRNA, microRNA, antisense oligonucleotides), gapmers, hybrids, ribozymes, phosphorodiamidate morpholinos, peptide nucleic acids, aptamers, and guide nucleic acids (e.g., Cas9 guide RNA), mRNA, and the like. In various embodiments, the polynucleotides can comprise one or more modified nucleotides. In various embodiments, the polynucleotides can comprise one or more modified internucleotide bonds. The polynucleotides can be single-stranded or double-stranded.

[1384] In some embodiments, the molecular cargo comprises at least one polynucleotide molecule. In some embodiments, the molecular cargo comprises at least 2, at least 3, at least 4, at least 5, or at least 10 polynucleotide molecules.

[1385] In some embodiments, the polynucleotide molecule is DNA. In some embodiments, the polynucleotide molecule is RNA.

[1386] In various embodiments, the polynucleotides described herein (e.g., interfering nucleic acids or guide RNAs) can comprise a region of complementarity to a target nucleic acid that can be in the range of 8 to 15, 8 to 30, 8 to 40, or 10 to 50, or 5 to 50, or 5 to 40 nucleotides in length. In certain embodiments, the length of the region of complementarity of a polynucleotide to a target nucleic acid can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 nucleotides. In some embodiments, the region of complementarity can be complementary to at least 10 consecutive nucleotides of a target nucleic acid. In some embodiments, the polynucleotide may contain 1, 2, 3, 4 or 5 base mismatches compared to a portion of consecutive nucleotides of the target nucleic acid. In some embodiments, the polynucleotide may have up to 3 mismatches on 15 bases, or up to 4 mismatches on 10 bases. In some embodiments, the polynucleotide is complementary to the target sequence of any one of the polynucleotides described herein (e.g., at least 80%, at least 85%, at least 90%, at least 95% or 100%). In various embodiments, such target sequences may be 100% complementary to the polynucleotides described herein. In some embodiments, any one or more thymine bases (T) in any one of the polynucleotides described herein may be uracil bases (U), and / or any one or more U may be T. The target sequence described herein may include a nucleic acid sequence in a target gene that is complementary to the guide sequence of the gRNA. The interaction between the target sequence and the guide sequence guides the RNA-guided DNA binder (e.g., Cas protein) to bind within the target sequence and may nick or cut (depending on the activity of the reagent).

[1387] The polynucleotides described herein may be modified, for example, to comprise modified nucleotides, modified internucleoside bonds and / or modified sugar moieties, or combinations thereof. In addition, the polynucleotides may have one or more of the following properties: improved cellular uptake compared to unmodified polynucleotides; non-toxic to cells or mammals, non-immunostimulatory; avoidance of pattern recognition receptors that do not mediate alternative splicing; nuclease resistance; improved endosomal export within the cell; or minimization of TLR stimulation. Any of the various modified chemical substances or forms of the polynucleotides disclosed herein may be combined together. As a non-limiting example, one, two, three, four, five, six, seven, eight or more different types of modifications may be contained within the same polynucleotide.

[1388] In various embodiments, specific nucleotide modifications can be used that render the polynucleotides into which the modifications are incorporated more resistant to nuclease digestion than native oligoribonucleotides or oligodeoxynucleotide molecules; such modified polynucleotides survive intact for longer periods of time than unmodified polynucleotides. Exemplary modified polynucleotides include those comprising modified backbones, for example, modified internucleoside linkages, such as methylphosphonate, phosphotriester, phosphorothioate short chain alkyl or cycloalkyl sugar linkages, heterocyclic sugar linkages, or short chain heteroatom linkages. Thus, the polynucleotides described herein can be stabilized, for example, via the incorporation of modifications (e.g., nucleotide modifications) to prevent nucleolytic degradation.

[1389] In various embodiments, the polynucleotide can be up to 50 nucleotides in length, of which 2 to 10, 2 to 15, 2 to 16, 2 to 17, 2 to 18, 2 to 19, 2 to 20, 2 to 25, 2 to 30, 2 to 40, or 2 to 45 nucleotides of the polynucleotide can be modified nucleotides. The polynucleotide can be 8 to 30 nucleotides in length, of which 2 to 10, 2 to 15, 2 to 16, 2 to 17, 2 to 18, 2 to 19, 2 to 20, 2 to 25, 2 to 30 nucleotides of the polynucleotide can be modified nucleotides. In some embodiments, the polynucleotide can be 8 to 15 nucleotides in length, wherein 2 to 4, 2 to 5, 2 to 6, 2 to 7, 2 to 8, 2 to 9, 2 to 10, 2 to 11, 2 to 12, 2 to 13, 2 to 14 nucleotides of the polynucleotide are modified nucleotides. In some embodiments, the polynucleotide can have every nucleotide except 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 nucleotides that are modified.

[1390] In various embodiments, the polynucleotides disclosed herein may comprise at least one nucleoside modified, for example, at the 2' position of the sugar. In some embodiments, all nucleosides in the polynucleotide are 2'-modified nucleosides. In some embodiments, the polynucleotides comprise at least one 2'-modified nucleoside.

[1391] In various embodiments, the polynucleotides disclosed herein can be one or more non-bicyclic 2'-modified nucleosides, such as 2'-O-dimethylaminoethyloxyethyl (2'-O-DMAEOE), 2'-O-methyl (2'-O-Me), 2'-O-dimethylaminoethyl (2'-O-DMAOE), 2'-O-methoxyethyl (2'-MOE), 2'-deoxy, 2'-ON-methylacetamido (2'-O-NMA) modified nucleosides, 2'-fluoro (2'-F), 2'-O-aminopropyl (2'-O-AP), or 2'-O-dimethylaminopropyl (2'-O-DMAP).

[1392] In some embodiments, the polynucleotides described herein may comprise one or more 2'-4' bicyclic nucleosides, wherein the ribose ring may comprise a bridge portion, for example, connecting the two atoms in the ring (e.g., connecting the 2'-O atom to the 4'-C atom via an ethylene (ENA) bridge, a methylene (LNA) bridge, or an (S)-constrained ethyl (cEt) bridge). Non-limiting examples of ENAs are disclosed in PCT Publication No. WO 2005 / 042777; Morita et al., Nucleic Acid Res., Suppl 1:241-242, 2001; Koizumi, Curr. Opin. Mol. Ther., 8:144-149, 2006, Surono et al., Hum. Gene Ther., 15:749-757, 2004; and Horie et al., Nucleic Acids Symp. Ser (Oxf), 49:171-172, 2005, the disclosures of which are incorporated herein by reference in their entirety. Non-limiting examples of LNAs are disclosed in PCT Patent Application Publication No. WO 2008 / 043753, the contents of which are incorporated herein by reference in their entirety. Non-limiting examples of cEt are disclosed in US Patent Nos. 7,569,686, 7,101,993, and 7,399,845, each of which is incorporated herein by reference in its entirety.

[1393] In various embodiments, the polynucleotides described herein may comprise modified nucleosides disclosed in, for example, U.S. Patent Nos. 8,022,193; 7,569,686; 7,399,845; 7,741,457; 7,335,765; 7,816,333; 8,957,201; 7,314,923, the entire contents of each of which are incorporated herein by reference for all purposes.

[1394] In various embodiments, the polynucleotide comprises at least one modified nucleoside that results in an increase in the Tm of the polynucleotide in the range of 1° C. to 10° C., compared to a polynucleotide not having the at least one modified nucleoside. A polynucleotide can have a plurality of modified nucleosides that result in an overall increase in the Tm of the polynucleotide in the range of 2° C., 3° ​​C., 4° C., 5° C., 6° C., 7° C., 8° C., 9° C., 10° C., 15° C., 20° C., 25° C., 30° C., 35° C., 40° C., 45° C., 50° C., 55° C., 60° C. or more, compared to a polynucleotide not having the modified nucleoside.

[1395] In some embodiments, polynucleotides can comprise a mixture of different types of nucleosides. Polynucleotides can comprise a mixture of deoxyribonucleosides or ribonucleosides and nucleosides modified by 2'-O-Me. Polynucleotides can comprise a mixture of 2'-4' bicyclic nucleosides and 2'-MOE, 2'-fluorine or nucleosides modified by 2'-O-Me. Polynucleotides can comprise a mixture of non-bicyclic 2'-modified nucleosides (e.g., 2'-MOE, 2'-fluorine or 2'-O-Me) and 2'-4' bicyclic nucleosides (e.g., LNA, ENA, cEt). Polynucleotides can comprise a mixture of 2'-deoxyribonucleosides or ribonucleosides and nucleosides modified by 2'-fluorine. Polynucleotides can comprise a mixture of 2'-fluorine-modified nucleosides and nucleosides modified by 2'-O-Me.

[1396] In various embodiments, oligonucleotide can comprise different types of alternating nucleosides. In certain embodiments, oligonucleotide can comprise alternating deoxyribonucleosides or ribonucleosides and nucleosides modified through 2'-O-Me. In certain embodiments, polynucleotide can comprise alternating 2'-deoxyribonucleosides or ribonucleosides and nucleosides modified through 2'-fluorine. In certain embodiments, oligonucleotide can comprise alternating nucleosides modified through 2'-fluorine and nucleosides modified through 2'-O-Me. In certain embodiments, oligonucleotide can comprise alternating 2'-4' bicyclic nucleosides and 2'-MOE, 2'-fluorine or nucleosides modified through 2'-O-Me. In certain embodiments, oligonucleotide can comprise alternating non-bicyclic 2'-modified nucleosides (e.g., 2'-MOE, 2'-fluorine or 2'-O-Me) and 2'-4' bicyclic nucleosides (e.g., LNA, ENA, cEt).

[1397] In various embodiments, the polynucleotides described herein can comprise one or more abasic residues, a 5-vinylphosphonate modification, and / or one or more inverted abasic residues.

[1398] In various embodiments, the oligonucleotide can include a phosphorothioate or other modified internucleoside bond. In various embodiments, the oligonucleotide can include a phosphorothioate internucleoside bond. In various embodiments, the oligonucleotide includes a phosphorothioate internucleoside bond between at least two nucleotides. In various embodiments, the oligonucleotide includes a phosphorothioate internucleoside bond between all nucleotides. By way of non-limiting example, in certain embodiments, the oligonucleotide includes a modified internucleoside bond at a first internucleoside bond, a second internucleoside bond, and / or (for example, and) a third internucleoside bond between the 5' end or 3' end of the nucleotide sequence.

[1399] Non-limiting examples of phosphorus-containing linkages include aminoalkylphosphotriester phosphorothioates, chiral phosphorothioates, phosphotriesters, phosphorodithioates, methyl and other alkyl phosphonates (including 3' alkylene phosphonates and chiral phosphonates), phosphinates, phosphoramidates (including 3'-amino phosphoramidate and aminoalkyl phosphoramidates), thioalkylphosphonates, thiophosphoramidates, thioalkylphosphotriesters, and boranophosphates with normal 3'-5' linkages, 2'-5' linked analogs of these, and those with reverse polarity, wherein adjacent pairs of nucleoside units link 3'-5' to 5'-3' or 2'-5' to 5'-2'; see U.S. Pat. Nos. 5,625,050, 4,469,863, 4,476,301, 5,683, 6,704, 7,666, 8,840, 8,113, 9,120, 11,130, 11,140, ​​12,150, 13,160, 14,170, 15,180, 16,190, 17,190, 18,190, 19,110, 19,111, 1 No. 5,023,243, No. 5,550,111, No. 5,177,196, No. 5,587,361, No. 5,188,897, No. 5,264,423, No. 5,276,019, No. 5,519,126, No. 5,278,302, No. 5,286,717, No. 5,321,131, No. 5,399,676, No. 5,405,939, No. 5,453,496, No. 5,455,233, No. 5,466,677, No. 5,476,925, No. 5,536,821, No. 5,541,306, No. 5,563,253, No. 5,571,799 and No. 3,687,808.

[1400] In various embodiments, the polynucleotides described herein can have a heteroatom backbone, for example, or a peptide nucleic acid (PNA) backbone (in which the phosphodiester backbone of the oligonucleotide is replaced by a polyamide backbone, with the nucleotides bound directly or indirectly to the aza nitrogen atoms of the polyamide backbone, see Nielsen et al., Science 1991, 254, 1497), a morpholino backbone (see Summerton and Weller, U.S. Patent No. 5,034,506); an amide backbone (see DeMesmaeker et al., Ace. Chem. Res. 1995, 28: 366-374); or an MMI or methylene (methylimino) backbone.

[1401] The nitrogenous base can be a conventional base (A, G, C, T, U), an analog thereof (e.g., a modified uridine such as 5-methoxyuridine, pseudouridine or N1-methylpseudouridine or others); inosine; a derivative of a purine or pyrimidine (e.g., N4-methyldeoxyguanosine, a deazapurine or azapurine, a deazapyrimidine or azapyrimidine, a pyrimidine base having a substituent group at the 5 or 6 position (e.g., 5-methylcytosine), a purine base having a substituent group at the 2, 6 or 8 position, 2-amino-6-methylaminopurine, 6-O-methylguanine, 4-thio-pyrimidine, 4-amino-pyrimidine, 4-dimethylhydrazine-pyrimidine and 4-O-alkyl-pyrimidine); U.S. Pat. No. 5,378,825 and PCT Publication No. WO 93 / 13121). For a general discussion, see Adams et al., The Biochemistry of the Nucleic Acids 5-36, 11th ed., 1992. Nucleic acids may contain one or more "abasic" residues, in which the backbone does not contain nitrogenous bases for polymer positions (U.S. Pat. No. 5,585,481). Nucleic acids may contain only conventional RNA or DNA sugars, bases, and bonds, or may contain conventional components and substitutes (e.g., conventional nucleosides with 2' methoxy substituents, or polymers containing both conventional nucleotides and one or more nucleotide analogs). Nucleic acids include "locked nucleic acids" (LNA), analogs containing one or more LNA nucleotide monomers in which a bicyclic furanose unit is locked in an RNA that mimics a sugar conformation, which enhances hybridization affinity for complementary RNA and DNA sequences (Vester and Wengel, 2004, Biochemistry 43(42):13233-41). RNA and DNA have different sugar moieties and may differ by the presence of uracil or its analogs in RNA and the presence of thymine or its analogs in DNA.

[1402] Interfering nucleic acids

[1403] In some embodiments, the conjugated molecular cargo can comprise a polynucleotide molecule capable of modifying the expression of one or more genes in a target cell (e.g., inhibiting gene expression and / or translation, regulating RNA splicing, or inducing exon skipping). In some embodiments, the polynucleotide molecule can be an interfering nucleic acid molecule targeting, for example, RNA (e.g., mRNA), such as siRNA, shRNA, miRNA, or antisense oligonucleotide (ASO).

[1404] In certain embodiments, an interfering nucleic acid molecule that selectively targets and inhibits the activity or expression of a product (e.g., an mRNA product) of a target gene is used in the compositions and methods described herein. An interfering nucleic acid molecule can inhibit the expression or activity of a product (e.g., an mRNA product) of at least one target gene by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95% or 100%. The reagents disclosed herein can include a core base sequence that has at least 80%, at least 85%, at least 90%, at least 95% or 100% complementarity to the product (e.g., mRNA product) of at least a target gene. Without wishing to be bound by theory, the "complementarity" of a nucleic acid can mean that a nucleotide sequence in one nucleic acid chain forms hydrogen bonds with another sequence on the relative nucleic acid chain due to the orientation of its core base groups. The complementary bases in DNA are typically A and T and C and G. In RNA, they are typically C and G and U and A. Complementarity can be perfect or substantial / enough. The perfect complementarity between two nucleic acids means that the two nucleic acids can form a duplex, wherein each base in the duplex is bonded to the complementary base by Watson-Crick pairing (Watson-Crickpairing). "Substantially" or "enough" complementarity means that the sequence in one chain is not completely and / or completely complementary to the sequence in the relative chain, but enough bonding occurs between the bases on the two chains to form a stable hybrid complex under a set of hybridization conditions (e.g., salt concentration and temperature). Such conditions can be predicted by using sequence and standard mathematical calculations to predict the Tm (melting temperature) of the hybrid chain, or by using conventional methods to determine the Tm experience. The temperature when Tm is included in the hybrid complex group formed between the two nucleic acid chains denaturation 50% (i.e., the double-stranded nucleic acid molecule group is half dissociated into a single chain). At a temperature lower than Tm, it is conducive to the formation of the hybrid complex, and at a temperature higher than Tm, it is conducive to the melting or separation of the chain in the hybrid complex. The Tm of a nucleic acid with known G+C content in 1 M aqueous NaCl can be estimated by using, for example, Tm = 81.5 + 0.41 (% G+C), although other known Tm calculations take into account nucleic acid structural properties.

[1405] The interfering nucleic acid can comprise a sequence of cyclic subunits, each with base pairing moieties connected by intersubunit bonds that allow the base pairing moieties to hybridize to a target sequence in a nucleic acid (typically RNA) by Watson-Crick base pairing to form a nucleic acid:oligomer heteroduplex within the target sequence.

[1406] Typically, at least 17, 18, 19, 20, 21, 22 or 23 nucleotides of the complementary sequence of the target mRNA sequence are sufficient to mediate the inhibition of the target transcript. Perfect complementarity is not necessary. In some embodiments, the interfering nucleic acid molecule is a single-stranded RNA. In some embodiments, the interfering nucleic acid molecule is a double-stranded RNA. The double-stranded RNA molecule can have 1 to 3 nucleotide 3' and / or 5' overhangs in the sense strand and / or antisense strand. In some embodiments, the double-stranded RNA molecule has 2 nucleotide 3' overhangs. In some embodiments, the two RNA chains are connected via a hairpin structure, thereby forming an shRNA molecule. The shRNA molecule can contain a hairpin derived from a microRNA molecule.

[1407] The interfering nucleic acid molecules described herein may contain RNA bases, non-RNA bases, or a mixture of RNA bases and non-RNA bases. For example, the interfering nucleic acid molecules described herein may be primarily composed of RNA bases or modified RNA bases, but may also contain DNA bases, modified DNA bases, and / or non-naturally occurring nucleotides. In the case of modified RNA or nucleotide substitutes, the term "ribonucleotide" or "nucleotide" may also refer to a modified nucleotide or substitute replacing a portion at one or more positions.

[1408] In some embodiments, the interfering nucleic acid molecule is a small interfering RNA (siRNA), also referred to as short interfering RNA or silencing RNA. siRNA is a class of double-stranded RNA molecules, typically about 20 to 25 base pairs in length, whose target nucleic acid (e.g., mRNA) is degraded via the RNA interference (RNAi) pathway in the cell. Such siRNA molecules typically include a region sufficiently homologous to the target region, and have sufficient length in terms of nucleotides so that the siRNA molecules lower the target nucleic acid. There is no need for perfect complementation between the siRNA molecule and the target, but correspondence must be sufficient to enable the siRNA molecule to guide sequence-specific silencing such as by RNAi cutting of the target RNA. In some embodiments, the sense strand only needs to be fully complementary to the antisense strand to maintain the overall double-stranded characteristics of the molecule.

[1409] In some embodiments, the length of siRNA molecule is about 35 to about 70 base pairs.In some embodiments, the length of siRNA molecule is about 35 to about 70 base pairs.In some embodiments, the length of siRNA molecule is about 35 to about 70 base pairs.In some embodiments, the length of siRNA molecule is about 35 to about 70 base pairs. In some embodiments, the siRNA molecule is 8 to 40 base pairs in length, 10 to 20 base pairs in length, 10 to 30 base pairs in length, 15 to 20 base pairs in length, 19 to 23 base pairs in length, or 21 to 24 base pairs in length. In some embodiments, the sense strand and antisense strand of the siRNA molecule are each independently about 19 to about 24 nucleotides in length. In some embodiments, the sense strand of the siRNA molecule is 23 nucleotides in length and the antisense strand is 21 nucleotides in length. In some embodiments, both the sense strand and the antisense strand of the siRNA molecule are 21 nucleotides in length.

[1410] After selecting a suitable target RNA sequence, suitable methods can be used to design and prepare siRNA molecules comprising a nucleotide sequence complementary to all or a portion of the target sequence (i.e., an antisense sequence) (see, for example, U.S. Patent Publication Nos. 2004 / 0077574 and 2008 / 0081791 and PCT Publication No. WO 2004 / 016735). In some embodiments, the siRNA molecule can be single-stranded (i.e., an ssRNA molecule comprising only an antisense strand) or double-stranded (i.e., a dsRNA molecule comprising an antisense strand and a complementary sense strand that hybridizes to form a dsRNA). In various embodiments, the siRNA molecule can comprise a duplex, an asymmetric duplex, a hairpin, or an asymmetric hairpin secondary structure comprising a self-complementary sense strand and / or antisense strand.

[1411] In various embodiments, the antisense strand of the siRNA molecule is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 nucleotides in length. In various embodiments, the antisense strand of the siRNA molecule is about 35 to about 70 nucleotides in length. In various embodiments, the antisense strand of the siRNA molecule is more than 70 nucleotides in length. In some embodiments, the antisense strand is 8 to 40 nucleotides in length, 10 to 20 nucleotides in length, 10 to 30 nucleotides in length, 15 to 20 nucleotides in length, 19 to 23 nucleotides in length or 21 to 24 nucleotides in length.

[1412] In some embodiments, the sense strand of the siRNA molecule is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 nucleotides in length. In various embodiments, the sense strand of the siRNA molecule is about 30 to about 70 nucleotides in length. In various embodiments, the sense strand of the siRNA molecule is greater than 70 nucleotides in length. In some embodiments, the sense strand is 8 to 40 nucleotides in length, 10 to 20 nucleotides in length, 10 to 30 nucleotides in length, 15 to 20 nucleotides in length, 19 to 23 nucleotides in length, or 21 to 24 nucleotides in length.

[1413] In various embodiments, the siRNA molecule can include an antisense strand comprising a complementary region to a target region in a target mRNA. In some embodiments, the complementary region is at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% complementary to the target region in the target mRNA. In some embodiments, the target region can include a region of consecutive nucleotides in the target mRNA. In some embodiments, the complementary region may not be required to be 100% complementary to the complementary region of its target, but may be specifically hybridizable or specific to the target RNA sequence.

[1414] In some embodiments, the siRNA molecules disclosed herein can comprise an antisense strand comprising a region of complementarity to a target RNA sequence, and the length of the region of complementarity ranges from 8 to 20, 8 to 35, 8 to 45, or 10 to 50, or 5 to 55, or 5 to 40 nucleotides. In some embodiments, the complementary region is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 nucleotides in length. In some embodiments, the complementary region is complementary to at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15, at least 16, at least 17, at least 18, at least 19, at least 20, at least 21, at least 22, at least 23, at least 24, at least 25, at least 30, at least 35 or more consecutive nucleotides of the target RNA sequence. In some embodiments, the siRNA molecule comprises an antisense strand having a nucleotide sequence that contains no more than 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 base mismatches compared to a consecutive nucleotide portion of the target RNA sequence. In some embodiments, the siRNA molecule comprises a nucleotide sequence that has at most 3 mismatches over 15 bases or at most 4 mismatches over 10 bases with the target sequence. In some embodiments, the siRNA molecule comprises an antisense strand having a nucleotide sequence that has at most 0, 1, 2, or 3 mismatches with the target sequence over 15 to 22 bases. In some embodiments, the siRNA molecule comprises an antisense strand having a nucleotide sequence that has 0, 1, or 2 mismatches with the target sequence over 15 to 22 bases. In some embodiments, the siRNA molecule comprises an antisense strand having a nucleotide sequence that has 0 or 1 mismatches with the target sequence over 15 to 22 bases. In some embodiments, the siRNA molecule comprises an antisense strand having a nucleotide sequence that has 0 mismatches with the target sequence over 15 to 22 bases.

[1415] In various embodiments, the siRNA molecule can comprise an antisense strand comprising a nucleotide sequence that is at least 70%, at least 75%, at least 85%, at least 90%, at least 95% or 100% complementary to the target RNA sequence of the antisense oligonucleotides disclosed herein. In some embodiments, the siRNA molecule comprises an antisense strand comprising a nucleotide sequence that is at least 70%, at least 75%, at least 85%, at least 90%, at least 95% or 100% identical to any antisense oligonucleotide provided herein. In some embodiments, the siRNA molecule comprises an antisense strand comprising at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15, at least 16, at least 17, at least 18, at least 19, at least 20, at least 21, at least 22, at least 23, at least 24, at least 25, at least 30, at least 35, or more contiguous nucleotides of any of the antisense oligonucleotides provided herein.

[1416] In some embodiments, double-stranded siRNA can comprise sense and antisense RNA chains of different lengths or the same length. In some embodiments, double-stranded siRNA molecules can also be produced by single oligonucleotides in stem-loop structures. The self-complementary sense region and antisense region of the siRNA molecule with stem-loop structure can be connected by a joint based on nucleic acid or a non-nucleic acid-based joint. In some embodiments, the siRNA with stem-loop structure includes a circular single-stranded RNA with two or more ring structures and a stem comprising self-complementary sense strand and antisense strand. In some embodiments, circular RNA can be processed in vivo or in vitro to produce active siRNA molecules that can mediate RNAi. Therefore, small hairpin RNA (shRNA) molecules are also envisioned herein. Such molecules can comprise specific antisense sequences and reverse complementary (sense) sequences, and in some cases, the reverse complementary sequences can be separated by spacer or loop sequences. Reverse complementary sequences as described herein can comprise sequences of complementary sequences as reference sequences, wherein the complementary sequences are written in opposite orientations. Due to the redundancy of codon usage, reverse complementary sequences may be different from reference sequences encoding the same polypeptide. As used herein, "reverse complement sequence" also includes a sequence that is, for example, at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identical to the reverse complement sequence of a reference sequence. Cutting of the spacer or loop can provide a single-stranded RNA molecule and its reverse complement sequence so that they can anneal to form a dsRNA molecule. In various embodiments, additional optional processing steps can result in the removal or addition of 1, 2, 3, 4, 5 or more nucleotides from the 3' end and / or 5' end of one or both chains. The spacer can have an appropriate length to allow the antisense sequence and the sense sequence to anneal and form a double-stranded structure or stem before cutting the spacer. In certain embodiments, subsequent optional processing steps can result in the removal or addition of 1, 2, 3, 4, 5, or more nucleotides from the 3' and / or 5' ends of one or both strands. In some embodiments, the spacer sequence can be an unrelated nucleotide sequence that can, for example, be located between two complementary nucleotide sequence regions that, when annealed into a double-stranded nucleic acid, can comprise an shRNA.

[1417] According to the type of designed siRNA molecule, the length of siRNA molecule can vary between about 10 to about 120 nucleotides. Usually, about 10 to about 55 of these nucleotides can be complementary to the RNA target sequence. For example, when siRNA is double-stranded siRNA or single-stranded siRNA, the length can vary between about 10 to about 55 nucleotides, and when siRNA is shRNA or circular molecule, the length can vary between about 30 nucleotides to about 110 nucleotides.

[1418] In various embodiments, the siRNA molecule can include a 3' overhang at one end of the molecule. In some embodiments, the other end can be blunt-ended or can also include an overhang (e.g., 5' and / or 3'). When the siRNA molecule includes an overhang at both ends of the molecule, the length of the overhang can be different or identical. In some embodiments, the siRNA molecule as described herein can include a 3' overhang of about 1 to about 3 nucleotides at both ends of the molecule. In some embodiments, the siRNA molecule includes a 3' overhang of about 1 to about 3 nucleotides on both the sense strand and the antisense strand. In some embodiments, the siRNA molecule includes a 3' overhang of about 1 to about 3 nucleotides on the antisense strand. In some embodiments, the siRNA molecule can include a 3' overhang of about 1 to about 3 nucleotides on the sense strand.

[1419] In various embodiments, the siRNA molecule comprises one or more modified nucleotides (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more). In some embodiments, all nucleotides of the sense strand and / or antisense strand of the siRNA molecule are modified. In certain embodiments, the siRNA molecule may comprise one or more modified nucleotides and / or one or more modified internucleotide bonds. In some embodiments, the siRNA molecule may comprise a modified internucleotide bond at the first internucleoside bond and the second internucleoside bond at the 5' end of the sense strand of the siRNA molecule. In some embodiments, the siRNA molecule may comprise a modified internucleotide bond at the first internucleoside bond and the second internucleoside bond at the 5' end and the 3' end of the antisense strand of the siRNA molecule. In some embodiments, the siRNA molecule can comprise modified internucleoside linkages at the first and second internucleoside linkages at the 5' end of the sense strand of the siRNA molecule and at the first and second internucleoside linkages at the 5' and 3' ends of the antisense strand of the siRNA molecule.

[1420] In some embodiments, the modified nucleotides may comprise a modified sugar moiety (e.g., a 2'-modified nucleotide). In some embodiments, the siRNA may comprise one or more 2'-modified nucleotides, such as 2'-deoxy, 2'-fluoro (2'-F), 2'-O-methyl (2'-O-Me), 2'-O-methoxyethyl (2'-MOE), 2'-O-aminopropyl (2'-O-AP), 2'-O-dimethylaminoethyl (2'-O-DMAOE), 2'-O-dimethylaminopropyl (2'-O-DMAP), 2'-O-dimethylaminoethyloxyethyl (2'-O-DMAEOE), or 2'-ON-methylacetamido (2'-O-NMA). In various embodiments, each nucleotide of the siRNA molecule may be a modified nucleotide (e.g., a 2'-modified nucleotide). In some embodiments, the siRNA molecule may comprise one or more phosphorodiamidate morpholinos. In some embodiments, each nucleotide of the siRNA molecule consists of a phosphorodiamidate morpholino.

[1421] In various embodiments, the siRNA molecule can include a phosphorothioate or other modified internucleotide bond. In various embodiments, the siRNA molecule can include, for example, a phosphorothioate internucleoside bond. In some embodiments, the siRNA molecule can include a phosphorothioate internucleoside bond between two or more nucleotides. In some embodiments, the siRNA molecule can include a phosphorothioate internucleoside bond between all nucleotides. In some embodiments, the siRNA molecule can include a modified internucleotide bond at the first internucleoside bond, the second internucleoside bond, and / or the third internucleoside bond at the 5' end or 3' end of the siRNA molecule. In some embodiments, the siRNA molecule can include a modified internucleotide bond at the first internucleoside bond and the second internucleoside bond at the 5' end and / or 3' end of the siRNA molecule. In some embodiments, the siRNA molecule can include a modified internucleotide bond at the first internucleoside bond and the second internucleoside bond at the 5' end of the siRNA molecule sense strand. In some embodiments, the siRNA molecule may comprise a modified internucleotide bond at the first internucleoside bond and the second internucleoside bond at the 5' end and the 3' end of the antisense strand of the siRNA molecule. In some embodiments, the siRNA molecule may comprise a modified internucleotide bond at the first internucleoside bond and the second internucleoside bond at the 5' end of the sense strand of the siRNA molecule and at the first internucleoside bond and the second internucleoside bond at the 5' end and the 3' end of the antisense strand of the siRNA molecule. In some embodiments, the siRNA molecule may comprise a modified internucleotide bond at the first internucleoside bond at the 5' end and the 3' end of the sense strand of the siRNA molecule, at the first internucleoside bond, the second internucleoside bond, and the third internucleoside bond at the 5' end of the antisense strand of the siRNA molecule, and at the first internucleoside bond at the 3' end of the antisense strand of the siRNA molecule.

[1422] In various embodiments, modified internucleotide bond can include phosphorus-containing bond.In some embodiments, the phosphorus-containing bond that can be used in the methods or compositions described herein includes but is not limited to chiral phosphorothioate, phosphorothioate, phosphorodithioate, aminoalkylphosphotriester, phosphotriester, methyl and other alkylphosphonates (including 3' alkylenephosphonates and chiral phosphonates), phosphoramidate (including 3'-aminophosphoramidate and aminoalkylphosphoramidate), phosphinate, thioalkylphosphonates, thiophosphoramidate, thioalkylphosphotriester and borane phosphate with normal 3'-5' bond, the analogue of these 2'-5' connections and those with opposite polarity, wherein adjacent nucleoside units are to 3'-5' connected to 5'-3' or 2'-5' connected to 5'-2'; See U.S. Patent Nos. 5,625,050, 3,687,808, 4,694,736, 5,737,964, 6,626,948, 6,673,965, 6,674,979, 7,662,983, 7,664,993, 7,665,994, 7,666,995, 7,667,996, 7,664,997, 7,664,998, 7,664,9 ... No. 4,469,863, No. 4,476,301, No. 5,177,196, No. 5,455,233, No. 5,264,423, No. 5,276,019, No. 5,278,302, No. 5,286,717, No. 5,321,131, No. 5,399,676, No. 5,405,939, No. 5,519 ,126, No. 5,453,496, No. 5,466,677, No. 5,476,925, No. 5,536,821, No. 5,023,243, No. 5,541,306, No. 5,550,111, No. 5,563,253, No. 5,571,799, No. 5,587,361 and No. 5,188,897.

[1423] Any of the various modified forms or chemistries of the siRNA molecules disclosed herein can be combined together. For example, but not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 or more different types of modifications can be included in the same siRNA molecule.

[1424] In various embodiments, the antisense strand can comprise one or more modified nucleotides (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or more). In some embodiments, the antisense strand can comprise one or more modified nucleotides and / or one or more modified internucleotide linkages. In some embodiments, the modified nucleotides can comprise modified sugar moieties (e.g., 2' modified nucleotides). In some embodiments, the antisense strand comprises one or more 2'-modified nucleotides, such as 2'-deoxy, 2'-fluoro (2'-F), 2'-O-methyl (2'-O-Me), 2'-O-methoxyethyl (2'-MOE), 2'-O-aminopropyl (2'-O-AP), 2'-O-dimethylaminoethyl (2'-O-DMAOE), 2'-O-dimethylaminopropyl (2'-O-DMAP), 2'-O-dimethylaminoethyloxyethyl (2'-O-DMAEOE), or 2'-O-N-methylacetamido (2'-O-NMA). In various embodiments, each nucleotide of the antisense strand can be a modified nucleotide (e.g., a 2'-modified nucleotide). In some embodiments, the antisense strand can comprise one or more phosphorodiamidate morpholinos. In some embodiments, the antisense strand consists of a phosphorodiamidate morpholino oligomer (PMO).

[1425] In some embodiments, the antisense strand contains a bond between phosphorothioate or other modified nucleotides. In some embodiments, the antisense strand can include a bond between phosphorothioate nucleosides. In some embodiments, the antisense strand can include a bond between phosphorothioate nucleosides between two or more nucleotides. In some embodiments, the antisense strand can include a bond between phosphorothioate nucleosides between all nucleotides. In some embodiments, the antisense strand can include a bond between modified nucleotides at the first nucleotide, the second nucleotide, and / or the third nucleotide at the 5' end or 3' end of the antisense strand. In some embodiments, the antisense strand can include a bond between modified nucleotides at the first nucleotide position and the second nucleotide position (e.g., between the first nucleotide and the second nucleotide and between the second nucleotide and the third nucleotide) at the 5' end and 3' end of the antisense strand.

[1426] In various embodiments, modified internucleotide bonds may include the phosphorus-containing bond of the antisense strand. In some embodiments, the phosphorus-containing bond that may be used in the methods and compositions described herein includes but is not limited to chiral phosphorothioates, phosphorothioates, phosphorodithioates, aminoalkylphosphotriesters, phosphotriesters, methyl and other alkylphosphonates (including 3' alkylenephosphonates and chiral phosphonates), phosphoramidates (including 3'-aminophosphoramidates and aminoalkylphosphoramidates), phosphinates, thioalkylphosphonates, thiophosphoramidates, thioalkylphosphotriesters and boranephosphates with normal 3'-5' bonds, the analogs of these 2'-5' connections and those with opposite polarity, wherein adjacent nucleoside units are connected 3'-5' to 5'-3' or 2'-5' to 5'-2'; see U.S. Patents Nos. 5,625,050, 3,687,808, 4,694,736, 5,737,964, 6,629,101, 6,643,113, 6,676,121, 6,697,133, 6,678,150, 6,647,163, 6,679,171, 6,684,173, 6,698,181, 6,679,193, 6,685,194, 6,699,113, 6,754,115, 6,768,116, 6,699,123, 6,679,133, 6,699,151, 6,679,133, 6,699,1 No. 4,469,863, No. 4,476,301, No. 5,177,196, No. 5,455,233, No. 5,264,423, No. 5,276,019, No. 5,278,302, No. 5,286,717, No. 5,321,131, No. 5,399,676, No. 5,405,939, No. 5,519 ,126, No. 5,453,496, No. 5,466,677, No. 5,476,925, No. 5,536,821, No. 5,023,243, No. 5,541,306, No. 5,550,111, No. 5,563,253, No. 5,571,799, No. 5,587,361 and No. 5,188,897.

[1427] Any of the modified forms or chemistries of the antisense strands disclosed herein can be combined together. For example, but not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more different types of modifications can be included in the same antisense strand.

[1428] In some embodiments, the sense strand comprises one or more modified nucleotides (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, or more). In some embodiments, the antisense strand can comprise one or more modified nucleotides and / or one or more modified internucleotide linkages. In some embodiments, the modified nucleotides can comprise modified sugar moieties (e.g., 2' modified nucleotides). In some embodiments, the antisense strand comprises one or more 2'-modified nucleotides, such as 2'-deoxy, 2'-fluoro (2'-F), 2'-O-methyl (2'-O-Me), 2'-O-methoxyethyl (2'-MOE), 2'-O-aminopropyl (2'-O-AP), 2'-O-dimethylaminoethyl (2'-O-DMAOE), 2'-O-dimethylaminopropyl (2'-O-DMAP), 2'-O-dimethylaminoethyloxyethyl (2'-O-DMAEOE), or 2'-O-N-methylacetamido (2'-O-NMA). In various embodiments, each nucleotide of the antisense strand can be a modified nucleotide (e.g., a 2'-modified nucleotide). In some embodiments, the antisense strand can comprise one or more phosphorodiamidate morpholinos. In some embodiments, the antisense strand consists of a phosphorodiamidate morpholino oligomer (PMO).

[1429] In some embodiments, the sense strand contains a phosphorothioate or other modified internucleotide bond. In some embodiments, the sense strand may include a phosphorothioate internucleoside bond. In some embodiments, the sense strand may include a phosphorothioate internucleoside bond between two or more nucleotides. In some embodiments, the sense strand may include a phosphorothioate internucleoside bond between all nucleotides. For example, in some embodiments, the sense strand comprises a modified internucleotide bond at the first nucleotide, second nucleotide, and / or third nucleotide at the 5' end or 3' end of the sense strand. In some embodiments, the sense strand may include a modified internucleotide bond at the first nucleotide position and the second nucleotide position (e.g., between the first nucleotide and the second nucleotide and between the second nucleotide and the third nucleotide) at the 5' end of the sense strand.

[1430] In various embodiments, modified internucleotide bonds may include phosphorus bonds of the sense strand. In some embodiments, the phosphorus bonds that may be used in the methods and compositions described herein include, but are not limited to, chiral phosphorothioates, phosphorothioates, phosphorodithioates, aminoalkylphosphotriesters, phosphotriesters, methyl and other alkylphosphonates (including 3' alkylenephosphonates and chiral phosphonates), phosphoramidates (including 3'-aminophosphoramidates and aminoalkylphosphoramidates), phosphinates, thioalkylphosphonates, thiophosphoramidates, thioalkylphosphotriesters and boranephosphates with normal 3'-5' bonds, analogs of the 2'-5' connections of these, and those with opposite polarity, wherein adjacent nucleoside units are connected 3'-5' to 5'-3' or 2'-5' to 5'-2'; see U.S. Patents Nos. 5,625,050, 3,687,808, 4,694,736, 5,708, 6,113, 6,123, 6,137, 6,156, 6,170, 6,183, 6,191, 6,117, 6,127, 6,136, 6,157, 6,178, 6,199, 7,111, 7,129, 7,130, 7,143, 7,158, 7,161, 7,177, 7,189, 7,191, 7,113, 7,127, 7,131, 7,147, 7,159, 7,161, 7,178, 7,189, 7,194, 7,11 No. 4,469,863, No. 4,476,301, No. 5,177,196, No. 5,455,233, No. 5,264,423, No. 5,276,019, No. 5,278,302, No. 5,286,717, No. 5,321,131, No. 5,399,676, No. 5,405,939, No. 5,519 ,126, No. 5,453,496, No. 5,466,677, No. 5,476,925, No. 5,536,821, No. 5,023,243, No. 5,541,306, No. 5,550,111, No. 5,563,253, No. 5,571,799, No. 5,587,361 and No. 5,188,897.

[1431] Any of the modified chemistries or forms of the sense strand described herein can be combined together. For example, but not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 or more different types of modifications can be included in the same sense strand.

[1432] In various embodiments, the antisense strand and / or sense strand of siRNA molecule can include one or more modifications that can enhance or reduce the silencing complex (RISC) of such as RNA induction. In some embodiments, the antisense strand of siRNA molecule can include one or more modifications that can enhance the loading of RISC. In various embodiments, the sense strand of siRNA molecule can include one or more modifications that can reduce the loading of RISC and / or reduce the modification of off-target effects. In various embodiments, the antisense strand of siRNA can include 2'-O-methoxyethyl (2'-MOE) modifications. In some embodiments, for example, adding 2'-O-methoxyethyl (2'-MOE) groups at the cleavage site can, for example, improve the silencing activity and / or specificity of siRNA by promoting the silencing complex (RISC) of the oriented RNA induction of the modified chain, for example, as disclosed in Song et al., (2017) Mol Ther Nucleic Acids 9: 242-250, which is incorporated herein by reference in its entirety. In various embodiments, the antisense strand of the siRNA molecule can include a 2'-O-Me-phosphorodithioate modification. In some embodiments, the 2'-O-Me-phosphorodithioate modification can increase RISC loading, for example, as disclosed in Wu et al., (2014) Nat Commun 5:3459, which is incorporated herein by reference in its entirety.

[1433] In various embodiments, the sense strand of the siRNA molecule can include a 5'-nitroindole modification. In some embodiments, the 5'-nitroindole modification can reduce the RNAi efficacy of the sense strand and / or reduce off-target effects, for example, as disclosed in Zhang et al., (2012) Chembiochem 13(13): 1940-1945, which is incorporated herein by reference in its entirety. In various embodiments, the sense strand can include a 2'-O-methyl (2'-O-Me) modification. In some embodiments, the 2'-O-Me modification can reduce RISC loading and / or off-target effects of the sense strand, for example, as disclosed in Zheng et al., FASEB (2013) 27(10): 4017-4026, which is incorporated herein by reference in its entirety. In various embodiments, the sense strand of the siRNA molecule may be fully substituted with morpholino, 2'-MOE and / or 2'-O-Me residues and may not be recognized by RISC, e.g., as disclosed in Kole et al., (2012) Nature reviews. Drug Discovery 11(2):125-140, which is incorporated herein by reference in its entirety.

[1434] In various embodiments, the sense strand of the siRNA molecule can include 5'-morpholino modifications. In various embodiments, 5'-morpholino modifications can reduce the RISC loading of the sense strand and / or improve RNAi activity and / or antisense strand selection, for example, as disclosed in Kumar et al., (2019) Chem Commun (Camb) 55 (35): 5139-5142, which is incorporated herein by reference in its entirety. In various embodiments, the sense strand of the siRNA molecule can be modified, for example, with a synthetic RNA-like high-affinity nucleotide analog called a locked nucleic acid (LNA), which can reduce the RISC loading of the sense strand and promote the incorporation of the antisense strand into RISC, for example, as disclosed in Elman et al., (2005) Nucleic Acids Res. 33 (1): 439-447, which is incorporated herein by reference in its entirety. In various embodiments, the sense strand of the siRNA molecule can include 5' unlocking nucleic acid (UNA) modifications. In various embodiments, the 5' unlocking nucleic acid (UNA) modification can reduce RISC loading of the sense strand and / or improve the silencing ability of the antisense strand, for example, as disclosed in Snead et al. (2013) Mol Ther Nucleic Acids 2(7):e103, which is incorporated herein by reference in its entirety.

[1435] In some embodiments, the antisense strand of the siRNA molecule may include a 2'-MOE modification and / or the sense strand may include a 2'-O-Me modification (see, for example, Song et al., (2017) Mol Ther Nucleic Acids 9: 242-250). In some embodiments, at least one (e.g., at least 2, at least 3, at least 4, at least 5, at least 6, at least 5, at least 8, at least 9, at least 10 or more) siRNA molecule may be covalently conjugated to an anti-TfR antigen binding protein as described herein, for example. In some embodiments, the anti-TfR antigen binding protein may be conjugated to the 5' end of the sense strand of the siRNA molecule. In some embodiments, the anti-TfR antigen binding protein may be conjugated to the 3' end of the sense strand of the siRNA molecule. In some embodiments, the anti-TfR antigen binding protein may be conjugated to the interior of the sense strand of the siRNA molecule. In some embodiments, the anti-TfR antigen binding protein may be conjugated to the 5' end of the antisense strand of the siRNA molecule. In some embodiments, the anti-TfR antigen binding protein can be conjugated to the 3' end of the antisense strand of the siRNA molecule. In some embodiments, the anti-TfR antigen binding protein is conjugated internally to the antisense strand of the siRNA molecule.

[1436] In addition, siRNA molecule can be modified or comprise nucleoside surrogate.The single-stranded region of siRNA molecule can be modified or comprise nucleoside surrogate, for example one or more unpaired regions of hairpin structure, for example connect the zone of two complementary regions, can have modification or nucleoside surrogate.One or more 3 ' ends or 5 ' ends (for example, for exonuclease) of stabilizing siRNA molecule or be conducive to the modification that antisense siRNA reagent enters RISC also be useful.Modification can comprise C3 (or C6, C7, C12) amino linker, thiol linker, carboxyl linker, non-nucleotide spacer (for example, C3-C12 (for example, C3, C6, C9, C12), no base, triethylene glycol, hexaethylene glycol), biotin or fluorescein reagent, they appear with phosphoramidite form and have the hydroxyl group of another DMT protection, thereby allow repeatedly coupling during RNA synthesis.

[1437] In some embodiments, the sense strand is 23 nucleotides in length, and the antisense strand is 21 nucleotides in length. In some embodiments, the sense strand is 23 nucleotides in length, and the antisense strand is 21 nucleotides in length, wherein the 3' end and 5' end nucleotide positions of the sense strand are reverse abasic residues. The 3' end and 5' end reverse abasic residues of the sense strand can be overhangs. The reverse abasic residues can be connected via a 3'-3' phosphodiester bond. In some embodiments, the antisense strand of the siRNA molecule contains 1 to 2 phosphorothioate bonds at the 3' end and / or 5' end. In some embodiments, the antisense strand contains two or three phosphorothioate internucleotide bonds at the 5' end and contains 1 phosphorothioate internucleotide bond at the 3' end. The siRNA molecule can be connected to the targeting moiety at the 5' end or 3' end of the sense strand.

[1438] In some embodiments, the sense strand is 21 nucleotides in length, and the antisense strand is 23 nucleotides in length, wherein the antisense strand contains 2 nucleobase 3' overhangs. In some embodiments, the antisense strand of the siRNA molecule contains 1 to 3 phosphorothioate bonds at the 3' end and the 5' end, and the sense strand of the siRNA molecule contains 1 to 2 phosphorothioate bonds at the 5' end. In some embodiments, the antisense strand of the siRNA molecule contains 2 to 3 phosphorothioate bonds at the 5' end and 2 phosphorothioate bonds at the 3' end, and the sense strand of the siRNA molecule contains 2 phosphorothioate bonds at the 5' end. The siRNA molecule can be connected to the targeting moiety at the 5' end or the 3' end of the sense strand.

[1439] In some embodiments, the interfering nucleic acid molecule is a short hairpin RNA (shRNA). " Small hairpin RNA " or " short hairpin RNA " or " shRNA " as described herein can comprise a short RNA sequence for preparing a tight hairpin loop (tight hairpin turn), which can be used to interfere with gene expression silence via RNA. The shRNA provided herein can be chemically synthesized or transcribed by a transcription cassette in a DNA plasmid. The shRNA hairpin structure can be cut into siRNA by the cellular mechanism, and then the siRNA is bound to the RNA-induced silencing complex (RISC).

[1440] Non-limiting examples of shRNA include double-stranded polynucleotide molecules assembled from single-stranded molecules, wherein the sense and antisense regions are connected...

Claims

1. A protein-drug conjugate comprising an antigen binding protein that specifically binds to human transferrin receptor, wherein the antigen binding protein is conjugated to a molecular cargo, and wherein the antigen binding protein binds to a transferrin receptor with a K of about 41 nM. D or stronger affinity to bind to human transferrin receptor.

2. The protein-drug conjugate of claim 1, wherein the antigen binding protein comprises an antibody or an antigen binding fragment thereof.

3. The protein-drug conjugate of claim 2, wherein the antigen binding protein is selected from a humanized antibody or antigen binding fragment thereof, a human antibody or antigen binding fragment thereof, a murine antibody or antigen binding fragment thereof, a chimeric antibody or antigen binding fragment thereof, a monovalent Fab', a divalent Fab2, a F(ab)'3 fragment, a single-chain fragment variable region (scFv), a double scFv, (scFv)2, a double-chain antibody, a bivalent antibody, a one-armed antibody, a minibody, a nanobody, a three-chain antibody, a four-chain antibody, a disulfide-stabilized Fv protein (dsFv), a single domain antibody (sdAb), an IgNAR, a single heavy chain antibody, a bispecific antibody or a binding fragment thereof, a bispecific T cell engager (BiTE), a trispecific antibody, or a chemically modified derivative thereof.

4. The protein-drug conjugate of any one of claims 1 to 3, wherein the antigen binding protein comprises a fragment antigen binding region (Fab).

5. The protein-drug conjugate of any one of claims 1 to 3, wherein the antigen binding protein comprises a single-chain fragment variable region (scFv).

6. The protein-drug conjugate of claim 5, wherein the scFv comprises a heavy chain variable region (HCVR or VVR) arranged from N-terminus to C-terminus in the following orientation: H ) and light chain variable region (LCVR or V L ):HCVR-LCVR.

7. The protein-drug conjugate of claim 5, wherein the scFv comprises a HCVR and a LCVR arranged from N-terminus to C-terminus in the following orientation: LCVR-HCVR.

8. The protein-drug conjugate according to any one of claims 5 to 7, wherein the scFv variable regions are connected via a linker.

9. The protein-drug conjugate of claim 8, wherein the linker is a peptide linker.

10. The protein-drug conjugate of claim 9, wherein the peptide linker is -(GGGGS) n -(SEQ ID NO:426); wherein n is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

11. The protein-drug conjugate of any one of claims 1 to 3, wherein the antigen binding protein comprises a bivalent antibody.

12. The protein-drug conjugate of any one of claims 1 to 3, wherein the antigen binding protein comprises a one-armed antibody.

13. The protein-drug conjugate of any one of claims 1 to 12, wherein the antigen binding protein binds to human transferrin receptor with a KD of about 3 nM or stronger affinity. The protein-drug conjugate of claim 13 , wherein the antigen binding protein binds to human transferrin receptor with a KD of about 0.45 nM to 3 nM.

15. The protein-drug conjugate of any one of claims 1 to 13, wherein the antigen binding protein comprises: (i) a HCVR comprising a HCDR1, a HCDR2, and a HCDR3 and having an amino acid sequence as set forth in SEQ ID NO: 2, 12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132, 142, 152, 162, 172, 182, 192, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 302, or 312 (or a variant thereof); and / or (ii) a LCVR comprising LCDR1, LCDR2, and LCDR3 and having an amino acid sequence set forth in SEQ ID NO: 7, 17, 27, 37, 47, 57, 67, 77, 87, 97, 107, 117, 127, 137, 147, 157, 167, 177, 187, 197, 207, 217, 227, 237, 247, 257, 267, 277, 287, 297, 307, or 317 (or a variant thereof).

16. The protein-drug conjugate according to any one of claims 1 to 15, wherein the antigen binding protein comprises: (1) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 2 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 7 (or a variant thereof); (2) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 12 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 17 (or a variant thereof); (3) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 22 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 27 (or a variant thereof); (4) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 32 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 37 or 465 (or a variant thereof); (5) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 42 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 47 (or a variant thereof); (6) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 52 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 57 (or a variant thereof); (7) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 62 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 67 (or a variant thereof); (8) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 72 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 77 (or a variant thereof); (9) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 82 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 87 (or a variant thereof); (10) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 92 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 97 (or a variant thereof); (11) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 102 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 107 (or a variant thereof); (12) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 112 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 117 (or a variant thereof); (13) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 122 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 127 (or a variant thereof); (14) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 132 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 137 (or a variant thereof); (15) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 142 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 147 (or a variant thereof); (16) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 152 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 157 (or a variant thereof); (17) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 162 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 167 (or a variant thereof); (18) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 172 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 177 (or a variant thereof); (19) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 182 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 187 (or a variant thereof); (20) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 192 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 197 (or a variant thereof); (21) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 202 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 207 (or a variant thereof); (22) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 212 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 217 (or a variant thereof); (23) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 222 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 227 (or a variant thereof); (24) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 232 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 237 (or a variant thereof); (25) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 242 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 247 (or a variant thereof); (26) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 252 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 257 (or a variant thereof); (27) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 262 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 267 (or a variant thereof); (28) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 272 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 277 (or a variant thereof); (29) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 282 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 287 (or a variant thereof); (30) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 292 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 297 (or a variant thereof); (31) a HCVR comprising HCDR1, HCDR2 and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 302 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2 and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 307 (or a variant thereof); and / or (32) A HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence shown in SEQ ID NO: 312 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence shown in SEQ ID NO: 317 (or a variant thereof).

17. The protein-drug conjugate of any one of claims 1 to 16, wherein the antigen binding protein comprises: (a) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 3 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 4 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 5 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 8 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 9 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 10 (or a variant thereof); (b) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 13 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 14 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 15 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 18 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 19 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 20 (or a variant thereof); (c) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 23 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 24 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 25 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 28 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 29 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 30 (or a variant thereof); (d) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 33 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 34 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 35 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 38 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 39 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 40 (or a variant thereof); (e) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 43 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 44 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 45 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 48 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 49 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 50 (or a variant thereof); (f) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 53 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 54 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 55 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 58 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 59 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 60 (or a variant thereof); (g) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 63 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 64 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 65 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 68 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 69 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 70 (or a variant thereof); (h) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 73 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 74 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 75 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 78 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 79 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 80 (or a variant thereof); (i) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 83 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 84 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 85 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 88 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 89 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 90 (or a variant thereof); (j) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 93 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 94 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 95 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 98 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 99 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 100 (or a variant thereof); (k) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 103 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 104 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 105 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 108 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 109 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 110 (or a variant thereof); (1) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 113 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 114 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 115 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 118 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 119 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 120 (or a variant thereof); (m) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 123 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 124 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 125 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 128 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 129 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 130 (or a variant thereof); (n) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 133 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 134 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 135 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 138 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 139 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 140 (or a variant thereof); (o) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 143 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 144 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 145 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 148 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 149 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 150 (or a variant thereof); (p) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 153 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 154 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 155 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 158 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 159 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 160 (or a variant thereof); (q) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 163 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 164 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 165 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 168 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 169 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 170 (or a variant thereof); (r) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 173 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 174 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 175 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 178 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 179 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 180 (or a variant thereof); (s) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 183 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 184 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 185 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 188 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 189 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 190 (or a variant thereof); (t) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 193 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 194 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 195 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 198 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 199 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 200 (or a variant thereof); (u) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 203 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 204 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 205 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 208 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 209 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 210 (or a variant thereof); (v) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 213 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 214 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 215 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 218 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 219 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 220 (or a variant thereof); (w) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 223 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 224 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 225 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 228 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 229 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 230 (or a variant thereof); (x) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 233 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 234 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 235 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 238 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 239 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 240 (or a variant thereof); (y) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 243 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 244 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 245 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 248 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 249 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 250 (or a variant thereof); (z) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 253 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 254 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 255 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 258 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 259 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 260 (or a variant thereof); (aa) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 263 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 264 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 265 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 268 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 269 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 270 (or a variant thereof); (ab) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 273 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 274 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 275 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 278 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 279 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 280 (or a variant thereof); (ac) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 283 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 284 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 285 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 288 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 289 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 290 (or a variant thereof); (ad) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 293 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 294 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 295 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 298 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 299 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 300 (or a variant thereof); (ae) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 303 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 304 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 305 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 308 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 309 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 310 (or a variant thereof); and / or (af) HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 313 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 314 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 315 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 318 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 319 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 320 (or a variant thereof).

18. The protein-drug conjugate of any one of claims 1 to 17, wherein the antigen binding protein comprises: (i) a HCVR having the amino acid sequence set forth in SEQ ID NO: 2 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 7 (or a variant thereof); (ii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 12 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 17 (or a variant thereof); (iii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 22 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 27 (or a variant thereof); (iv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 32 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 37 (or a variant thereof); (v) a HCVR having the amino acid sequence set forth in SEQ ID NO: 42 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 47 (or a variant thereof); (vi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 52 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 57 (or a variant thereof); (vii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 62 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 67 (or a variant thereof); (viii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 72 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 77 (or a variant thereof); (ix) a HCVR having the amino acid sequence set forth in SEQ ID NO: 82 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 87 (or a variant thereof); (x) a HCVR having the amino acid sequence set forth in SEQ ID NO: 92 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 97 (or a variant thereof); (xi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 102 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 107 (or a variant thereof); (xii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 112 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 117 (or a variant thereof); (xiii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 122 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 127 (or a variant thereof); (xiv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 132 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 137 (or a variant thereof); (xv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 142 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 147 (or a variant thereof); (xvi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 152 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 157 (or a variant thereof); (xvii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 162 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 167 (or a variant thereof); (xviii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 172 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 177 (or a variant thereof); (xix) a HCVR having the amino acid sequence set forth in SEQ ID NO: 182 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 187 (or a variant thereof); (xx) a HCVR having the amino acid sequence set forth in SEQ ID NO: 192 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 197 (or a variant thereof); (xxi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 202 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 207 (or a variant thereof); (xxii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 212 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 217 (or a variant thereof); (xxiii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 222 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 227 (or a variant thereof); (xxiv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 232 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 237 (or a variant thereof); (xxv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 242 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 247 (or a variant thereof); (xxvi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 252 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 257 (or a variant thereof); (xxvii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 262 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 267 (or a variant thereof); (xxviii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 272 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 277 (or a variant thereof); (xxix) a HCVR having the amino acid sequence set forth in SEQ ID NO: 282 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 287 (or a variant thereof); (xxx) a HCVR having the amino acid sequence set forth in SEQ ID NO: 292 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 297 (or a variant thereof); (xxxi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 302 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 307 (or a variant thereof); and / or (xxxii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 312 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 317 (or a variant thereof).

19. The protein-drug conjugate of any one of claims 1 to 4 and 11 to 18, wherein the antigen binding protein comprises: i. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 329 (or a variant thereof); and a light chain region having an amino acid sequence as shown in SEQ ID NO: 328 (or a variant thereof); ii. a heavy chain region having an amino acid sequence as set forth in SEQ ID NO: 331 (or a variant thereof); and a light chain region having an amino acid sequence as set forth in SEQ ID NO: 330 (or a variant thereof); iii. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 333 (or a variant thereof); and a light chain region having an amino acid sequence as shown in SEQ ID NO: 332 (or a variant thereof); iv. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 335 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 334 (or a variant thereof); v. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 337 (or a variant thereof); and a light chain region having an amino acid sequence as shown in SEQ ID NO: 336 (or a variant thereof); vi. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 339 (or a variant thereof); and a light chain region having an amino acid sequence as shown in SEQ ID NO: 338 (or a variant thereof); vii. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 341 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 340 (or a variant thereof); viii. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 343 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 342 (or a variant thereof); ix. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 345 (or a variant thereof); and a light chain region having an amino acid sequence as shown in SEQ ID NO: 344 (or a variant thereof); x. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 347 (or a variant thereof); and a light chain region having an amino acid sequence as shown in SEQ ID NO: 346 (or a variant thereof); xi. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 349 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 348 (or a variant thereof); xii. a heavy chain region having the amino acid sequence shown in SEQ ID NO: 351 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 350 (or a variant thereof); xiii. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 353 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 352 (or a variant thereof); xiv. a heavy chain region having the amino acid sequence of SEQ ID NO: 355 (or a variant thereof); and a light chain having the amino acid sequence of SEQ ID NO: 354 (or a variant thereof); xv. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 357 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 356 (or a variant thereof); xvi. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 359 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 358 (or a variant thereof); xvii. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 361 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 360 (or a variant thereof); xviii. A heavy chain region having the amino acid sequence shown in SEQ ID NO: 363 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 362 (or a variant thereof); xix. A heavy chain region having the amino acid sequence shown in SEQ ID NO: 365 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 364 (or a variant thereof); xx. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 367 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 366 (or a variant thereof); xxi. A heavy chain region having the amino acid sequence shown in SEQ ID NO: 369 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 368 (or a variant thereof); xxii. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 371 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 370 (or a variant thereof); xxiii. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 373 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 372 (or a variant thereof); xxiv. a heavy chain region having an amino acid sequence as shown in SEQ ID NO: 375 (or a variant thereof); and a light chain region having an amino acid sequence as shown in SEQ ID NO: 374 (or a variant thereof); xxv. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 377 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 376 (or a variant thereof); xxvi. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 379 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 378 (or a variant thereof); xxvii. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 381 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 380 (or a variant thereof); xxviii. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 383 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 382 (or a variant thereof); xxix. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 385 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 384 (or a variant thereof); xxx. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 387 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 386 (or a variant thereof); xxxi. A heavy chain region having an amino acid sequence as shown in SEQ ID NO: 389 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 388 (or a variant thereof); or xxxii. A heavy chain region having the amino acid sequence shown in SEQ ID NO: 391 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 390 (or a variant thereof).

20. The protein-drug conjugate of any one of claims 1 to 3 and 11 to 23, wherein the antigen binding protein comprises: i. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 543 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 328 (or a variant thereof); ii. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 544 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 330 (or a variant thereof); iii. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 545 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 332 (or a variant thereof); iv. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 546 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 334 (or a variant thereof); v. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 547 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 336 (or a variant thereof); vi. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 548 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 338 (or a variant thereof); vii. A heavy chain having the amino acid sequence shown in SEQ ID NO: 549 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 340 (or a variant thereof); viii. a heavy chain having the amino acid sequence shown in SEQ ID NO: 550 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 342 (or a variant thereof); ix. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 551 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 344 (or a variant thereof); x. a heavy chain having the amino acid sequence shown in SEQ ID NO: 552 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 346 (or a variant thereof); xi. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 553 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 348 (or a variant thereof); xii. a heavy chain having the amino acid sequence shown in SEQ ID NO: 554 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 350 (or a variant thereof); xiii. A heavy chain having the amino acid sequence shown in SEQ ID NO: 555 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 352 (or a variant thereof); xiv. a heavy chain having the amino acid sequence shown in SEQ ID NO: 556 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 354 (or a variant thereof); xv. A heavy chain having the amino acid sequence shown in SEQ ID NO: 557 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 356 (or a variant thereof); xvi. A heavy chain having an amino acid sequence as shown in SEQ ID NO: 558 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 358 (or a variant thereof); xvii. A heavy chain having the amino acid sequence shown in SEQ ID NO: 559 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 360 (or a variant thereof); xviii. A heavy chain having the amino acid sequence shown in SEQ ID NO: 560 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 362 (or a variant thereof); xix. A heavy chain having the amino acid sequence shown in SEQ ID NO: 561 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 364 (or a variant thereof); xx. A heavy chain having an amino acid sequence as shown in SEQ ID NO: 562 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 366 (or a variant thereof); xxi. A heavy chain having the amino acid sequence shown in SEQ ID NO: 563 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 368 (or a variant thereof); xxii. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 564 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 370 (or a variant thereof); xxiii. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 565 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 372 (or a variant thereof); xxiv. a heavy chain having an amino acid sequence as shown in SEQ ID NO: 566 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 374 (or a variant thereof); xxv. A heavy chain having an amino acid sequence as shown in SEQ ID NO: 567 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 376 (or a variant thereof); xxvi. A heavy chain having an amino acid sequence as shown in SEQ ID NO: 568 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 378 (or a variant thereof); xxvii. A heavy chain having an amino acid sequence as shown in SEQ ID NO: 569 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 380 (or a variant thereof); xxviii. A heavy chain having the amino acid sequence shown in SEQ ID NO: 570 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 382 (or a variant thereof); xxix. A heavy chain having an amino acid sequence as shown in SEQ ID NO: 571 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 384 (or a variant thereof); xxx. A heavy chain having an amino acid sequence as shown in SEQ ID NO: 572 (or a variant thereof); and a light chain having an amino acid sequence as shown in SEQ ID NO: 386 (or a variant thereof); xxxi. a heavy chain having the amino acid sequence shown in SEQ ID NO: 573 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 388 (or a variant thereof); or xxxii. A heavy chain having the amino acid sequence shown in SEQ ID NO: 574 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 390 (or a variant thereof).

21. The protein-drug conjugate of any one of claims 1 to 16, wherein the antigen binding protein comprises: (1) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 132 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 137 (or a variant thereof); (2) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 172 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 177 (or a variant thereof); (3) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 222 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 227 (or a variant thereof); (4) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 242 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 247 (or a variant thereof); (5) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 262 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 267 (or a variant thereof); or (6) a HCVR comprising HCDR1, HCDR2, and HCDR3 and having the amino acid sequence set forth in SEQ ID NO: 272 (or a variant thereof); and a LCVR comprising LCDR1, LCDR2, and LCDR3 and having the amino acid sequence set forth in SEQ ID NO: 277 (or a variant thereof).

22. The protein-drug conjugate of any one of claims 1 to 17 and 21, wherein the antigen binding protein comprises: (a) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 133 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 134 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 135 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 138 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 139 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 140 (or a variant thereof); (b) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 173 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 174 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 175 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 178 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 179 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 180 (or a variant thereof); (c) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 223 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 224 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 225 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 228 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 229 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 230 (or a variant thereof); (d) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 243 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 244 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 245 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 248 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 249 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 250 (or a variant thereof); (e) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 263 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 264 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 265 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 268 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 269 (or a variant thereof), and a LCDR3 having the amino acid sequence shown in SEQ ID NO: 270 (or a variant thereof); or (f) a HCVR comprising: a HCDR1 having the amino acid sequence shown in SEQ ID NO: 273 (or a variant thereof), a HCDR2 having the amino acid sequence shown in SEQ ID NO: 274 (or a variant thereof), and a HCDR3 having the amino acid sequence shown in SEQ ID NO: 275 (or a variant thereof); and A LCVR comprising: LCDR1 having the amino acid sequence shown in SEQ ID NO: 278 (or a variant thereof), LCDR2 having the amino acid sequence shown in SEQ ID NO: 279 (or a variant thereof), and LCDR3 having the amino acid sequence shown in SEQ ID NO: 280 (or a variant thereof).

23. The protein-drug conjugate of any one of claims 1 to 18 and 21 to 22, comprising: (i) a HCVR having the amino acid sequence set forth in SEQ ID NO: 132 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 137 (or a variant thereof); (ii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 172 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 177 (or a variant thereof); (iii) a HCVR having the amino acid sequence set forth in SEQ ID NO: 222 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 227 (or a variant thereof); (iv) a HCVR having the amino acid sequence set forth in SEQ ID NO: 242 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 247 (or a variant thereof); (v) a HCVR having the amino acid sequence set forth in SEQ ID NO: 262 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 267 (or a variant thereof); or (vi) a HCVR having the amino acid sequence set forth in SEQ ID NO: 272 (or a variant thereof); and a LCVR having the amino acid sequence set forth in SEQ ID NO: 277 (or a variant thereof).

24. The protein-drug conjugate of any one of claims 1 to 4 and 11 to 23, wherein the antigen binding protein comprises: (A) a heavy chain region having the amino acid sequence shown in SEQ ID NO: 355 (or a variant thereof); and a light chain region having the amino acid sequence shown in SEQ ID NO: 354 (or a variant thereof); (B) a heavy chain region having the amino acid sequence shown in SEQ ID NO: 363 (or a variant thereof); and a light chain region having the amino acid sequence shown in SEQ ID NO: 362 (or a variant thereof); (C) a heavy chain region having the amino acid sequence shown in SEQ ID NO: 373 (or a variant thereof); and a light chain region having the amino acid sequence shown in SEQ ID NO: 372 (or a variant thereof); (D) a heavy chain region having the amino acid sequence shown in SEQ ID NO: 377 (or a variant thereof); and a light chain region having the amino acid sequence shown in SEQ ID NO: 376 (or a variant thereof); (E) a heavy chain region having the amino acid sequence shown in SEQ ID NO: 381 (or a variant thereof); and a light chain region having the amino acid sequence shown in SEQ ID NO: 380 (or a variant thereof); or (F) a heavy chain region having the amino acid sequence shown in SEQ ID NO: 383 (or a variant thereof); and a light chain region having the amino acid sequence shown in SEQ ID NO: 382 (or a variant thereof).

25. The protein-drug conjugate of any one of claims 1 to 4 and 11 to 24, wherein the antigen binding protein comprises: (I) a heavy chain having the amino acid sequence shown in SEQ ID NO: 556 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 354 (or a variant thereof); (II) a heavy chain having the amino acid sequence shown in SEQ ID NO: 560 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 362 (or a variant thereof); (III) a heavy chain having the amino acid sequence shown in SEQ ID NO: 565 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 372 (or a variant thereof); (IV) a heavy chain having the amino acid sequence shown in SEQ ID NO: 367 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 376 (or a variant thereof); (V) a heavy chain having the amino acid sequence shown in SEQ ID NO: 569 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 380 (or a variant thereof); or (VI) a heavy chain having the amino acid sequence shown in SEQ ID NO: 570 (or a variant thereof); and a light chain having the amino acid sequence shown in SEQ ID NO: 382 (or a variant thereof).

26. The protein-drug conjugate of any one of claims 1 to 25, wherein the antigen binding protein binds to the same epitope on human transferrin receptor as an antibody comprising the HCVR / LCVR amino acid sequence pair shown in Table 1-1.

27. The protein-drug conjugate of any one of claims 1 to 25, wherein the antigen binding protein competes for binding to human transferrin receptor with an antibody comprising the HCVR / LCVR amino acid sequence pair shown in Table 1-1.

28. A protein-drug conjugate comprising an antigen binding protein that specifically binds to human transferrin receptor (hTfR), wherein the antigen binding protein is conjugated to a molecular cargo and comprises an antibody or antigen binding fragment thereof, wherein the antibody or antigen binding fragment thereof binds to one or more hTfR epitopes selected from the group consisting of: a. an epitope having the sequence LLNE (SEQ ID NO: 529) and / or an epitope having the sequence TYKEL (SEQ ID NO: 509); b. an epitope having the sequence DSTDFTGT (SEQ ID NO: 530) and / or an epitope having the sequence VKHPVTGQF (SEQ ID NO: 531) and / or an epitope having the sequence IERIPEL (SEQ ID NO: 532); c. an epitope having the sequence LNENSYVPREAGSQKDEN (SEQ ID NO: 533); d. an epitope having the sequence FEDL (SEQ ID NO: 521); e. an epitope having the sequence IVDKNGRL (SEQ ID NO: 534); f. an epitope having the sequence IVDKNGRLVY (SEQ ID NO: 535); g. an epitope having the sequence DQTKF (SEQ ID NO: 536); h. an epitope having the sequence LVENPGGY (SEQ ID NO: 537) and / or an epitope having the sequence PIVNAELSF (SEQ ID NO: 538) and / or an epitope having the sequence PYLGTTMDT (SEQ ID NO: 539); i. an epitope having the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope having the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope having the sequence TYKEL (SEQ ID NO: 509); j. an epitope having the sequence KRKLSEKLDSTDFTGTIKL (SEQ ID NO: 510) and / or an epitope having the sequence YTLIEKTMQNVKHPVTGQFL (SEQ ID NO: 511) and / or an epitope having the sequence LIERIPELNKVARAAAE (SEQ ID NO: 512); k. an epitope having the sequence LNENSYVPREAGSQKDENL (SEQ ID NO: 513); 1. an epitope having the sequence GTKKDFEDL (SEQ ID NO: 514); m. an epitope having the sequence SVIIVDKNGRLVYLVENPGGYVAYSK (SEQ ID NO: 515); n. an epitope having the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope having the sequence DQTKFPIVNAEL (SEQ ID NO: 517) and / or an epitope having the sequence TYKELIERIPELNK (SEQ ID NO: 518); o. an epitope having the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope having the sequence TYKELIERIPELNK (SEQ ID NO: 518); p. an epitope having the sequence SVIIVDKNGRLVYLVENPGGYVAY (SEQ ID NO: 519); q. an epitope having the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope having the sequence FGNMEGDCPSDWKTDSTCRM (SEQ ID NO: 520); r. an epitope having the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope having the sequence LVENPGGYVAYSKAATVTGKL (SEQ ID NO: 522) and / or an epitope having the sequence IYMDQTKFPIVNAELSF (SEQ ID NO: 523) and / or an epitope having the sequence ISRAAAEKL (SEQ ID NO: 524) and / or an epitope having the sequence VTSESKNVKLTVSNVLKE (SEQ ID NO: 525) and / or an epitope having the sequence FCEDTDYPYLGTTMDT (SEQ ID NO: 526); s. an epitope contained within or overlapping with the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope contained within or overlapping with the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope contained within or overlapping with the sequence TYKEL (SEQ ID NO: 509); t. an epitope contained within or overlapping with the sequence KRKLSEKLDSTDFTGTIKL (SEQ ID NO: 510) and / or an epitope contained within or overlapping with the sequence YTLIEKTMQNVKHPVTGQFL (SEQ ID NO: 511) and / or an epitope contained within or overlapping with the sequence LIERIPELNKVARAAAE (SEQ ID NO: 512); u. an epitope contained within or overlapping with the sequence LNENSYVPREAGSQKDENL (SEQ ID NO: 513); v. an epitope contained within or overlapping with the sequence GTKKDFEDL (SEQ ID NO: 514); w. an epitope contained within or overlapping with the sequence SVIIVDKNGRLVYLVENPGGYVAYSK (SEQ ID NO: 515); x. an epitope contained within or overlapping with the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope contained within or overlapping with the sequence DQTKFPIVNAEL (SEQ ID NO: 517) and / or an epitope contained within or overlapping with the sequence TYKELIERIPELNK (SEQ ID NO: 518); y. an epitope contained within or overlapping with the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope contained within or overlapping with the sequence TYKELIERIPELNK (SEQ ID NO: 518); z. an epitope contained within or overlapping with the sequence SVIIVDKNGRLVYLVENPGGYVAY (SEQ ID NO: 519); aa. an epitope contained within or overlapping with the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope contained within or overlapping with the sequence FGNMEGDCPSDWKTDSTCRM (SEQ ID NO: 520); and bb. an epitope contained within or overlapping with the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO:507) and / or an epitope contained within or overlapping with the sequence LVENPGGYVAYSKAATVTGKL (SEQ ID NO:522) and / or an epitope contained within or overlapping with the sequence IYMDQTKFPIVNAELSF (SEQ ID NO:523) and / or an epitope contained within or overlapping with the sequence ISRAAAEKL (SEQ ID NO:524) and / or an epitope contained within or overlapping with the sequence VTSESKNVKLTVSNVLKE (SEQ ID NO:525) and / or an epitope contained within or overlapping with the sequence FCEDTDYPYLGTTMDT (SEQ ID NO:526).

29. The protein-drug conjugate of claim 28, wherein the antibody or antigen-binding fragment thereof binds to one or more hTfR epitopes selected from the group consisting of: a. an epitope consisting of the sequence LLNE (SEQ ID NO: 529) and / or an epitope consisting of the sequence TYKEL (SEQ ID NO: 509); b. an epitope consisting of the sequence DSTDFTGT (SEQ ID NO: 530) and / or an epitope consisting of the sequence VKHPVTGQF (SEQ ID NO: 531) and / or an epitope consisting of the sequence IERIPEL (SEQ ID NO: 532); c. an epitope consisting of the sequence LNENSYVPREAGSQKDEN (SEQ ID NO: 533); d. an epitope consisting of the sequence FEDL (SEQ ID NO: 521); e. an epitope consisting of the sequence IVDKNGRL (SEQ ID NO: 534); f. an epitope consisting of the sequence IVDKNGRLVY (SEQ ID NO: 535); g. an epitope consisting of the sequence DQTKF (SEQ ID NO: 536); h. an epitope consisting of the sequence LVENPGGY (SEQ ID NO: 537) and / or an epitope consisting of the sequence PIVNAELSF (SEQ ID NO: 538) and / or an epitope consisting of the sequence PYLGTTMDT (SEQ ID NO: 539); i. an epitope consisting of the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope consisting of the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope consisting of the sequence TYKEL (SEQ ID NO: 509); j. an epitope consisting of the sequence KRKLSEKLDSTDFTGTIKL (SEQ ID NO: 510) and / or an epitope consisting of the sequence YTLIEKTMQNVKHPVTGQFL (SEQ ID NO: 511) and / or an epitope consisting of the sequence LIERIPELNKVARAAAE (SEQ ID NO: 512); k. an epitope consisting of the sequence LNENSYVPREAGSQKDENL (SEQ ID NO: 513); 1. an epitope consisting of the sequence GTKKDFEDL (SEQ ID NO: 514); m. an epitope consisting of the sequence SVIIVDKNGRLVYLVENPGGYVAYSK (SEQ ID NO: 515); n. an epitope consisting of the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope consisting of the sequence DQTKFPIVNAEL (SEQ ID NO: 517) and / or an epitope consisting of the sequence TYKELIERIPELNK (SEQ ID NO: 518); o. an epitope consisting of the sequence LLNENSYVPREAGSQKDEN (SEQ ID NO: 516) and / or an epitope consisting of the sequence TYKELIERIPELNK (SEQ ID NO: 518); p. an epitope consisting of the sequence SVIIVDKNGRLVYLVENPGGYVAY (SEQ ID NO: 519); q. an epitope consisting of the sequence IYMDQTKFPIVNAEL (SEQ ID NO: 508) and / or an epitope consisting of the sequence FGNMEGDCPSDWKTDSTCRM (SEQ ID NO: 520); and r. An epitope consisting of the sequence LLNENSYVPREAGSQKDENLAL (SEQ ID NO: 507) and / or an epitope consisting of the sequence LVENPGGYVAYSKAATVTGKL (SEQ ID NO: 522) and / or an epitope consisting of the sequence IYMDQTKFPIVNAELSF (SEQ ID NO: 523) and / or an epitope consisting of the sequence ISRAAAEKL (SEQ ID NO: 524) and / or an epitope consisting of the sequence VTSESKNVKLTVSNVLKE (SEQ ID NO: 525) and / or an epitope consisting of the sequence FCEDTDYPYLGTTMDT (SEQ ID NO: 526).

30. The protein-drug conjugate of claim 28 or claim 29, wherein the antigen binding protein is selected from a humanized antibody or antigen binding fragment thereof, a human antibody or antigen binding fragment thereof, a murine antibody or antigen binding fragment thereof, a chimeric antibody or antigen binding fragment thereof, a monovalent Fab', a divalent Fab2, a F(ab)'3 fragment, a single-chain fragment variable region (scFv), a double scFv, (scFv)2, a double-chain antibody, a bivalent antibody, a one-armed antibody, a minibody, a nanobody, a three-chain antibody, a four-chain antibody, a disulfide-stabilized Fv protein (dsFv), a single domain antibody (sdAb), an IgNAR, a single heavy chain antibody, a bispecific antibody or a binding fragment thereof, a bispecific T cell engager (BiTE), a trispecific antibody, or a chemically modified derivative thereof.

31. The protein-drug conjugate of any one of claims 1 to 30, wherein the molecular cargo is conjugated to: (i) the HCVR of the antigen binding protein, (ii) the LCVR of the antigen binding protein, (iii) the heavy chain of the antigen binding protein, and / or (iv) the light chain of the antigen binding protein.

32. The protein-drug conjugate according to any one of claims 1 to 31, wherein the molecular cargo is conjugated to the antigen binding protein via a glutamine residue and / or a lysine residue.

33. The protein-drug conjugate of claim 32, wherein the glutamine residue: (i) introduced into the N-terminus and / or C-terminus of the heavy chain of the antigen-binding protein, (ii) introduced into the N-terminus and / or C-terminus of the light chain of the antigen-binding protein, (iii) naturally occurs in the CH2 or CH3 domain of the antigen binding protein, (iv) introduced into the antigen binding protein by modifying one or more amino acids, and / or (v) is Q295 or mutated from N297 to Q297 (N297Q).

34. The protein-drug conjugate of claim 32 or 33, wherein the antigen binding protein comprises a glutamine-containing tag, and the molecular cargo is conjugated to the antigen binding protein via a glutamine residue of the glutamine-containing tag.

35. The protein-drug conjugate of claim 34, wherein the glutamine-containing tag comprises an amino acid sequence selected from the group consisting of LLQGG (SEQ ID NO: 439), LLQG (SEQ ID NO: 440), LSLSQG (SEQ ID NO: 441), gGGLLQGG (SEQ ID NO: 442), gLLQG (SEQ ID NO: 443), LLQ (SEQ ID NO: 444), gSPLAQSHGG (SEQ ID NO: 445), gLLQGGG (SEQ ID NO: 446), gLLQGG (SEQ ID NO: 447), gLLQ (SEQ ID NO: 448), LLQLLQGA (SEQ ID NO: 449), LLQGA (SEQ ID NO: 450), LLQYQGA (SEQ ID NO: 451), LLQGSG (SEQ ID NO: 452), LLQYQG (SEQ ID NO: 453), LLQLLQG (SEQ ID NO: 454). NO:454), SLLQG (SEQ ID NO:455), LLQLQ (SEQ ID NO:456), LLQLLQ (SEQ ID NO:457) and LLQGR (SEQ ID NO:458).

36. The protein-drug conjugate of any one of claims 1 to 35, wherein the antigen binding protein and the molecular cargo are conjugated via a linker.

37. The protein-drug conjugate of any one of claims 1 to 36, wherein the molecular cargo comprises a polynucleotide molecule, a vector, or a small molecule.

38. The protein-drug conjugate of any one of claims 1 to 37, wherein the molecular cargo comprises a polynucleotide molecule.

39. The protein-drug conjugate of claim 38, wherein the polynucleotide molecule is an interfering nucleic acid molecule, a guide RNA, a ribozyme, an aptamer, a hybrid, a multimer, or an mRNA.

40. The protein-drug conjugate of claim 39, wherein the interfering nucleic acid molecule is siRNA, shRNA, miRNA, antisense oligonucleotide, or gapmer.

41. The protein-drug conjugate of claim 40, wherein the interfering nucleic acid is siRNA.

42. The protein-drug conjugate of claim 40, wherein the siRNA inhibits DMPK, CNBP, dystrophin, DUX4, ApoE, MAPT, APP, HTT, SOD1, C9orf72, SNCA, LRRK2, PRNP, SLC5A1, SLC16A3, HDAC6, MMP27, MFAP5, FAM64A, BAIAP3, MYH7, TPM1, RBM20, KLHL24, MYL2, or TNNT2 genes, or mutants thereof.

43. The protein-drug conjugate of claim 41 or 42, wherein the siRNA comprises a sense strand of 21 nucleotides in length.

44. The protein-drug conjugate of any one of claims 41 to 43, wherein the siRNA comprises an antisense strand that is 23 nucleotides in length.

45. The protein-drug conjugate of any one of claims 41 to 44, wherein the siRNA comprises two phosphorothioate linkages at the first internucleoside linkage and the second internucleoside linkage at the 5' end of the sense strand.

46. ​​The protein-drug conjugate of any one of claims 41 to 45, wherein the siRNA comprises two phosphorothioate bonds at the first internucleoside bond and the second internucleoside bond at the 3' end and / or the 5' end of the antisense strand.

47. The protein-drug conjugate of claim 40, wherein the interfering nucleic acid is an antisense oligonucleotide.

48. The protein-drug conjugate of claim 39, wherein the polynucleotide molecule is a guide RNA.

49. The protein-drug conjugate of any one of claims 39 to 48, wherein the polynucleotide molecule comprises one or more modified nucleotides.

50. The protein-drug conjugate of any one of claims 1 to 37, wherein the molecular cargo comprises a carrier.

51. The protein-drug conjugate of claim 50, wherein the molecular cargo comprises a lipid-based carrier.

52. The protein-drug conjugate of claim 51, wherein the lipid-based carrier is a lipid nanoparticle (LNP), a liposome, a lipidoid, or a liposome complex.

53. The protein-drug conjugate of claim 52, wherein the lipid-based carrier is LNP.

54. The protein-drug conjugate of claim 53, wherein the LNP further comprises a polynucleotide molecule and / or a polypeptide molecule.

55. The protein-drug conjugate of claim 53 or 54, wherein the LNP comprises one or more components of a gene editing system.

56. The protein-drug conjugate of claim 55, wherein the LNP comprises (a) a Cas nuclease or a nucleic acid encoding the Cas nuclease, and / or (b) a guide RNA or one or more DNAs encoding the guide RNA.

57. The protein-drug conjugate of claim 56, wherein the Cas nuclease is a Cas9 protein.

58. The protein-drug conjugate of claim 57, wherein the Cas9 protein is derived from a Streptococcus pyogenes Cas9 protein, a Staphylococcus aureus Cas9 protein, a Campylobacter jejuni Cas9 protein, a Streptococcus thermophilus Cas9 protein, or a Neisseria meningitidis Cas9 protein.

59. The protein-drug conjugate of any one of claims 56 to 58, wherein the nucleic acid encoding the Cas protein is codon-optimized for expression in mammalian cells.

60. The protein-drug conjugate of claim 59, wherein the nucleic acid encoding the Cas protein is codon-optimized for expression in human cells.

61. The protein-drug conjugate of any one of claims 56 to 60, wherein the nucleic acid encoding the Cas nuclease comprises mRNA.

62. The protein-drug conjugate of any one of claims 39 and 56 to 61, wherein the guide RNA is a single guide RNA (sgRNA).

63. The protein-drug conjugate of claim 55, wherein the LNP comprises a zinc finger nuclease (ZFN) or a transcription activator-like effector nuclease (TALEN).

64. The protein-drug conjugate of any one of claims 53 to 63, wherein the lipid nanoparticle comprises a cationic lipid, a neutral lipid, a helper lipid, and a stealth lipid.

65. The protein-drug conjugate of claim 64, wherein the neutral lipid is distearoylphosphatidylcholine (DSPC).

66. The protein-drug conjugate of any one of claims 64 to 65, wherein the helper lipid is cholesterol.

67. The protein-drug conjugate of any one of claims 64 to 66, wherein the stealth lipid is PEG2k-DMG.

68. The protein-drug conjugate of any one of claims 1 to 67, wherein the antigen binding protein, when not conjugated to a molecular cargo, does not block more than 50% of the binding of the C-terminal fragment of the human transferrin receptor to human holo-transferrin that occurs in the absence of such antigen binding protein.

69. The protein-drug conjugate of claim 68, wherein the blocking is measured in an enzyme-linked immunosorbent assay (ELISA) plate assay, wherein the extracellular domain of the human transferrin receptor fused to a His6-myc-myc tag is pre-bound to the antigen binding protein and then contacted with holo-transferrin, which is immobilized to the surface of the plate by binding of an anti-homo-transferrin antibody bound to the plate.

70. The protein-drug conjugate of any one of claims 68 to 70, wherein the binding of the holo-transferrin and human transferrin receptor extracellular domain is measured at a concentration of about 300 pM human transferrin receptor extracellular domain in the absence of the antigen binding protein.

71. The protein-drug conjugate of any one of claims 1 to 70, wherein the antigen binding protein has one or more of the following characteristics: a. Affinity for binding to monkey TfR at 25°C and in surface plasmon resonance format (K D ) has an affinity of about 0 nM (no detectable binding) or higher; b. K of monkey TfR binding at 25°C and in surface plasmon resonance format [ D / K binding to human TfR D ] has a ratio of 0 to 278; c. When in Fab format (lgG1), it blocks approximately 3% to 13% of hTfR binding to human Holo-Tf; d. When scFv (V K -V H ) form, blocks about 6% to 13% of hTfR binding to human Holo-Tf; and / or e. When scFv (V H -V L ) form, blocked about 11% to 26% of hTfR binding to human Holo-Tf.

72. A pharmaceutical composition comprising the protein-drug conjugate according to any one of claims 1 to 70 and a pharmaceutically acceptable carrier.

73. A composition or kit comprising the protein-drug conjugate or pharmaceutical composition thereof according to any one of claims 1 to 70 and an additional therapeutic agent.

74. The composition or kit of claim 73, wherein the additional therapeutic agent is selected from the group consisting of alglucosidase alfa, rituximab, methotrexate, intravenous immunoglobulin (IVIG), efrucisidase alfa, levalbuterol, antibiotics, cortisone, prednisone, bisphosphonates, and palivizumab.

75. The composition or kit of claim 73 or 74, wherein the additional therapeutic agent is selected from the group consisting of: a β2-adrenergic agonist, a steroid, a bisphosphonate, an infectious disease therapeutic, a vaccine, and a pneumococcal vaccine.

76. A complex comprising the protein-drug conjugate according to any one of claims 1 to 70 and a human transferrin receptor polypeptide or a fragment thereof bound thereto.

77. A method for preparing a protein-drug conjugate according to any one of claims 1 to 70, comprising (a) contacting the antigen binding protein with the molecular cargo under conditions that favor conjugation of the antigen binding protein and the molecular cargo; and (b) optionally, isolating the protein-drug conjugate produced in step (a).

78. A protein-drug conjugate which is the product of the method of claim 77.

79. A container or injection device comprising the protein-drug conjugate according to any one of claims 1 to 70 and 78.

80. A method for administering the protein-drug conjugate of any one of claims 1 to 70 and 78 to a subject, the method comprising introducing the protein-drug conjugate into the body of the subject.

81. The method of claim 80, wherein the protein-drug conjugate is introduced into the subject's body parenterally.

82. The method of claim 81, wherein the protein-drug conjugate is introduced into the subject's body intravenously.

83. The method of claim 80, wherein the protein-drug conjugate is introduced into the subject's body via intrathecal, intracerebroventricular, or intraparenchymal injection into the central nervous system.

84. A method for treating or preventing a disease or disorder in a subject in need thereof, the method comprising administering to the subject an effective amount of a protein-drug conjugate according to any one of claims 1 to 70 and 78.

85. The method of claim 84, wherein the disease or disorder is a lysosomal storage disease or disorder, a cardiac disease or disorder, a central nervous system (CNS) disease or disorder, an eye disease or disorder, a brain disease or disorder, a spinal cord disease or disorder, a peripheral nervous system (PNS) disease or disorder, a muscle disease or disorder, a cartilage disease or disorder, a bone growth plate disease or disorder, a kidney disease or disorder, or a blood disease or disorder.

86. The method of claim 84, wherein the disease or disorder is a neurological disease or disorder.

87. The method of claim 86, wherein the neurological disease or condition is a lysosomal storage disease, amyloidosis, neuropathy, neurodegenerative disease, seizures, behavioral disorders, leukodystrophy, neuropsychiatric disease, traumatic brain injury, neurodevelopmental disease, neuromuscular disease, ocular disease or condition, viral or microbial infection, inflammation, ischemia, and cancer.

88. The method of any one of claims 84 to 87, wherein the disease or disorder is a lysosomal storage disease.

89. The method of claim 87, wherein the neurodegenerative disease is Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, Parkinson's disease, or a prion disease.

90. The method of claim 89, wherein the molecular cargo of the protein-drug conjugate is an siRNA selected from the group consisting of siRNAs that inhibit ApoE, MAPT, APP, HTT, SOD1, C9orf72, SNCA, LRRK2, or PRNP genes or mutants thereof.

91. The method of claim 85, wherein the disease or condition is a cardiac disease or condition.

92. The method of claim 91, wherein the cardiac disease or condition is heart failure.

93. The method of claim 92, wherein the molecular cargo of the protein-drug conjugate is an siRNA selected from the group consisting of siRNAs that inhibit SLC5A1, SLC16A3, HDAC6, MMP27, MFAP5, FAM64A, BAIAP3, MYH7, TPM1, RBM20, KLHL24, MYL2, or TNNT2 genes or mutants thereof.

94. The method of claim 85, wherein the disease or disorder is a muscle disease or disorder.

95. The method of claim 94, wherein the muscle disease or disorder is myotonic dystrophy, Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, facioscapulohumeral muscular dystrophy type 1, or muscle atrophy.

96. The method of claim 95, wherein the molecular cargo of the protein-drug conjugate is an siRNA selected from the group consisting of siRNAs that inhibit DMPK, CNBP, dystrophin, or DUX4 genes or mutants thereof.

97. The method of any one of claims 84 to 96, wherein the protein-drug conjugate is administered to the subject in combination with an additional therapeutic agent.

98. The method of claim 97, wherein the additional therapeutic agent is selected from the group consisting of alglucosidase alfa, rituximab, methotrexate, intravenous immunoglobulin (IVIG), efrucisidase alfa, levalbuterol, antibiotics, cortisone, prednisone, bisphosphonates, and palivizumab.

99. The method of claim 97, wherein the additional therapeutic agent is selected from the group consisting of: a β2-adrenergic agonist, a steroid, a bisphosphonate, an infectious disease therapeutic, a vaccine, and a pneumococcal vaccine.

100. A method for delivering a molecular cargo to a tissue or cell type in a subject, the method comprising administering to the subject an antigen binding protein that specifically binds to human transferrin receptor or an antigenic fragment or variant thereof and a molecular cargo conjugated thereto.

101. The method of claim 100, wherein the molecular cargo comprises a polynucleotide molecule, a vector, or a small molecule.

102. The method of any one of claims 100 to 101, wherein the tissue is brain / spinal cord / CNS, eye, skeletal muscle, adipose tissue, blood / bone marrow, breast, lung / bronchus, colon, uterus, esophagus, heart, kidney, liver, lymph node, ovary, pancreas, placenta, prostate, rectum, skin, peripheral blood mononuclear cells (PBMC), small intestine, spleen, stomach, testicles, peripheral nervous system, and / or bone / cartilage / joints.

103. The method of any one of claims 100 to 102, wherein the cell type and the tissue associated with the cell type are as follows:

104. The method of any one of claims 84 to 103, wherein the method comprises piercing the subject's body with a needle of a syringe and then injecting the antigen binding protein that specifically binds to transferrin receptor or an antigenic fragment or variant thereof and the molecular cargo conjugated thereto into the subject's body.

105. The method of any one of claims 84 to 104, wherein the subject has a muscle dystrophy, a metabolic disease, sarcopenia, or cachexia.

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