Miniproteins, conjugates & uses thereof

Abstract

Provided herein are polypeptides and conjugates thereof, including radionuclide conjugates, useful in compositions and methods of treating, diagnosing, monitoring, and / or imaging a disease, disorder, or condition associated with expression of one or more targets, including Nectin-4.

Description

Docket No.: AKT-031WO MINIPROTEINS, CONJUGATES & USES THEREOF CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application Nos.63 / 587,042, filed on September 29, 2023; 63 / 598,874, filed on November 5 14, 2023; 63 / 618,228, filed on January 5, 2024; and 63 / 636,078, filed on April 18, 2024, the disclosures of each of which are incorporated by reference herein in their entireties for all purposes. SEQUENCE LISTING

[0002] This application contains a Sequence Listing that has been submitted 0 electronically in XML format and is hereby incorporated by reference in its entirety. The XML file, created on September 26, 2024, is named AKT-031WO_SL.xml, and is 488,567 bytes in size. BACKGROUND

[0003] Cancer is a leading cause of death worldwide. Classical cancer therapies such as5 radiotherapy, chemotherapy, and surgical procedures can be accompanied by severe side effects including those due to killing of healthy non-cancerous cells. Newer therapeutics enhance the targeting of cytotoxic drugs to tumor cells, relative to earlier therapies, including those that use biologics conjugates. SUMMARY 0

[0004] The present disclosure provides technologies such as compositions and methods of use and manufacture thereof to address needs in the field of cancer. For example, in contrast to classical cancer diagnostics or therapies, targeted molecules can be designed to increase specificity and decrease toxicity of, e.g., imaging or therapeutic modalities. For instance, delivery of a therapeutic having a chelator and / or radionuclide (e.g., alpha emitter)5 using a polypeptide to specifically target the therapeutic to the tumor microenvironment provides focused treatment to tumor cells and avoids or reduces risk of toxicity to surrounding healthy tissues.

[0005] In contrast to classical cancer therapies, radionuclide therapies are more targeted and less toxic. For instance, delivery of a radionuclide specifically to a tumor 0 microenvironment allows for selective radiation of tumor tissue, effectively killing malignant cells while preserving the surrounding healthy tissue. For example, a radionuclide can IPTS / 128722251.1 Page 1 of 337Docket No.: AKT-031WO employ a targeting molecule that specifically binds to an antigen expressed at an increased level and / or density on the surface of tumor cells relative to non-tumor cells. Binding of the radionuclide to the antigen-positive tumor cells targets radiation to those cells without targeting healthy tissue. Full-length antibodies have previously been evaluated as targeting 5 moieties; however, due to considerations such as their large size, full-length antibodies, or even antibody fragments (e.g., fragments larger than polypeptides provided herein) can have several challenges such as having poor tumor tissue penetration, longer circulating half-life which leads to normal tissue irradiation, as well as challenges such as manufacturing, and storage, among other things. Accordingly, a need remains for new approaches to specifically0 target tumors, and particularly solid tumors. The present disclosure provides technologies that meet this and other needs. Among other things, the present disclosure provides compositions comprising polypeptides and conjugates thereof with improved tumor penetration, decreased off-target toxicity and / or accumulation, and improved affinity for Nectin-4, as compared to currently existing technologies (e.g., antibodies, e.g., antibody-drug5 conjugates, polypeptides, etc.). In addition, the disclosure provides the insight that compositions and conjugates provided herein can be even further improved. Contemplated herein, in some embodiments, conjugates, such as radionuclide conjugates of the disclosure may be improved, such as improvement on one or more measures, such as efficacy and / or reduction in toxicity grade and / or off-target effects, by modification of one or more amino0 acids in a polypeptide sequence of the conjugate and / or addition of one or more decoys.

[0006] In some aspects, the present disclosure provides polypeptides comprising certain amino acid sequences. In some embodiments, these polypeptides bind to Nectin-4 with certain affinities.

[0007] In one aspect, the disclosure provides a composition, comprising a polypeptide of5 at least 44 amino acids in length and having an amino sequence comprising that set forth in SEQ ID NO: 171, wherein X2 is E or D; X6 is E or Q; X17 is G or A; X21 is Q, Y, or E; X26 is Kme3, Kme2, Kme, K, Kipr, or S; X32 is A, G, or D; X41 is N or K; and X45 is S or absent.

[0008] In one aspect, the disclosure provides a composition, comprising a polypeptide of0 at least 44 amino acids in length and having an amino acid sequence comprising that set forth in SEQ ID NO: 176, wherein X2 is E or D; X6 is E or Q; X9 is T or A; X10 is A or G; X12 is A, Kme3, Kme2, Kme, Kipr or K; X13 is R or (Cit) X17 is G or A; X21 is Q, Y, or E; X24 is Q or K; X25 is A or K; X26 is Kme3, Kme2, Kme, K, Kipr, or S; X28 is Q or K; X29 is Y or K; X30 is L or V; X32 is A, G, or D; X41 is N or K; and X45 is S or absent. IPTS / 128722251.1 Page 2 of 337Docket No.: AKT-031WO

[0009] In another aspect, the disclosure provides a composition, comprising a Nectin-4 binding polypeptide having an amino acid sequence comprising at least 44 amino acids, wherein the amino acids include (i) a cysteine at each of four positions corresponding to 1, 20, 34, and 44 of SEQ ID NO: 195; (ii) SEQ ID NO: 169 at positions corresponding to 5 positions 9-15 of SEQ ID NO: 195; (iii) QKKme3 at positions corresponding to positions 24, 25, and 26 of SEQ ID NO: 195; and (iv) QYL at positions corresponding to positions 28, 29, and 30 of SEQ ID NO: 195.

[0010] In one aspect, the disclosure provides a composition, comprising a Nectin-4 binding polypeptide having an amino acid sequence comprising at least 44 amino acids,0 wherein the amino acids include (i) a cysteine at each of four positions corresponding to 1, 20, 34, and 44 of SEQ ID NO: 200; (ii) SEQ ID NO: 247 at positions corresponding to positions 9-15 of SEQ ID NO: 200; (iii) QKKme3 at positions corresponding to positions 24, 25, and 26 of SEQ ID NO: 200; and (iv) QYL at positions corresponding to positions 28, 29, and 30 of SEQ ID NO: 200. 5

[0011] In another aspect, the disclosure provides a composition, comprising a Nectin-4 binding polypeptide having an amino acid sequence, wherein the amino acid sequence comprises: at least four cysteines, which form two disulfide bonds; at least one modified lysine residue at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the modification comprises at least one small alkyl group attached to the nitrogen of the0 lysine side chain, optionally comprising a methyl, dimethyl, trimethyl, or isopropyl group; at least 44 amino acids in length; and has a binding affinity for Nectin-4 stronger than 100 nM in a cell-based assay.

[0012] In some embodiments, the polypeptide is at least 40 amino acids in length, but no greater than 100 amino acids in length. 5

[0013] In some embodiments, the polypeptide binds to Nectin-4 with an affinity of stronger than 10 nM in a cell-based assay.

[0014] In some embodiments, the amino acid sequence of the polypeptide shares at least 90% identity to any one of SEQ ID NOs: 3-158, 161-168, 177-208, or 212-215, but includes at least one lysine with at least one modification comprising at least one small alkyl group0 bonded to the nitrogen of the side chain, optionally selected from: trimethyl, dimethyl, monomethyl, and isopropyl.

[0015] In some embodiments, the amino acid sequence of the polypeptide shares at least 90% identity to at least 44 amino acids of a reference polypeptide, which reference polypeptide is longer than 44 amino acids in length and binds to Nectin-4 with a strength of IPTS / 128722251.1 Page 3 of 337Docket No.: AKT-031WO at least 10 nM on a cell-based assay, and / or has an inhibition constant of no greater than 10 nM.

[0016] In some embodiments, the amino acid sequence of the polypeptide shares at least 90% identity to at least 40 amino acids of any one of SEQ ID NOs: 3-158, 161-168, 177-208, 5 or 212-215, provided that the 40 amino acids includes at least four cysteine residues that form two disulfide bridges.

[0017] In some embodiments, the amino acid sequence of the polypeptide shares at least 90% identity to at least 35 contiguous amino acids of any one of SEQ ID NOs: 3-158, 161- 168, 177-208, or 212-215, provided that the 40 amino acids includes at least four cysteine0 residues that form two disulfide bridges.

[0018] In some embodiments, the amino acid sequence of the polypeptide shares 100% identity to at least 44 amino acids of a reference polypeptide, which reference polypeptide is longer than 44 amino acids in length.

[0019] In certain embodiments, the amino acid sequence shares 90% identity to at least5 44 amino acids as set forth in any one of SEQ ID NO: 78, 83, 85, 99, 103, 162-168, 195, or 200.

[0020] In certain embodiments, the amino acid sequence shares 100% identity to at least 44 amino acids as set forth in any one of SEQ ID NO: 78, 83, 85, 99, 103, 162-168, 195, or 200. 0

[0021] In one aspect, the disclosure provides a composition comprising a polypeptide having an amino acid sequence comprising SEQ ID NO: 195.

[0022] In another aspect, the disclosure provides a composition comprising a compound as set forth in C251 of Table 2A, having an amino acid sequence comprising SEQ ID NO: 195 5

[0023] In one aspect, the disclosure provides a composition comprising a polypeptide having an amino acid sequence comprising SEQ ID NO: 200.

[0024] In one aspect, the disclosure provides a composition comprising a compound as set forth in C260 of Table 2A, having an amino acid sequence comprising SEQ ID NO: 200.

[0025] In some embodiments, the composition further comprises a radionuclide. 0

[0026] In some embodiments, the radionuclide is Ac-225, Cu-64, Ga-68, Lu-177, Pb- 212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

[0027] In one aspect, the disclosure provides a composition comprising a polypeptide having an amino acid sequence of at least 44 amino acids in length, but with four amino acid IPTS / 128722251.1 Page 4 of 337Docket No.: AKT-031WO substitutions at positions corresponding to 12, 21, 26, and 32 of SEQ ID NO: 78, wherein the substitutions correspond to K12A, Y21Q, S26Kme3, and G32A.

[0028] In some embodiments, the C-terminus has an -OH or an -NH2.

[0029] In certain embodiments, the binding affinity for Nectin-4 is stronger than 100 nM. 5

[0030] In certain embodiments, the inhibition constant is no greater than 100 nM.

[0031] In some embodiments, the composition further comprises one or more of a linker, chelator, and radionuclide.

[0032] In some embodiments, the linker comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG2, PEG, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-0 PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N- maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof.

[0033] In some embodiments, the chelator comprises or consists of DOTA, Crown,5 NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

[0034] In some embodiments, the radionuclide is selected from Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th- 232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211. 0

[0035] In some embodiments, if the polypeptide comprises any one of SEQ ID NO: 83, 85, 93, 99, 134, 138, 145, 155, 162-168, or 195 the polypeptide further comprises a linker, wherein the linker is PEG4, and an optional chelator, wherein the chelator is DOTA.

[0036] In certain embodiments, when present, the linker is attached to the N-terminus of the polypeptide. In certain embodiments, the C-terminal amino acid of the polypeptide is not5 a cysteine. In some embodiments, when present, the chelator is attached to either the polypeptide or the linker. In some embodiments, when present, the radionuclide is attached to the chelator.

[0037] In one aspect, the disclosure provides a composition comprising a formula selected from one or more of (M)x-L-C-R, (M)x-L-C, (M)x-C-R, (M)x-L-R, (M)x-C, (M)x-0 L, and (M)x-R, wherein M comprises a polypeptide (M), L comprises a linker (L), C comprises a chelator (C), R comprises a radionuclide (R), and x is 1, 2, 3, or 4, wherein M comprises an amino acid sequence of any one of SEQ ID NO: 162-176, 178-208, or 212-215.

[0038] In certain embodiments, the linker comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)- IPTS / 128722251.1 Page 5 of 337Docket No.: AKT-031WO PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N- maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof. 5

[0039] In some embodiments, the chelator comprises or consists of DOTA, Crown, NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

[0040] In some embodiments, the radionuclide Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm-0 153, Ra-225, Tb-165, or At-211.

[0041] In one aspect, the disclosure provides a composition comprising a formula selected from one or more of (M)x-L-C-R, (M)x-L-C, (M)x-C-R, (M)x-L-R, (M)x-C, (M)x- L, and (M)x-R, wherein M comprises a polypeptide (M), L comprises a linker (L), C comprises a chelator (C), R comprises a radionuclide (R), and x is 1, 2, 3, or 4, wherein M5 has an amino acid sequence comprising any one of those set forth in SEQ ID NOs: 162-176, 178-208, or 212-215.

[0042] In some embodiments, when L is present, L comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, lys(MPB)-PEG4, PEG36, an ester linker, an amide linker, a maleimide linker a valine-0 citrulline linker, a hydrazone linker, a N-succinimidyl-4-(2-pyridyldithio)butyrate (SPDB) linker, a succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) linker, a vinylsulfone-based linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof. 5

[0043] In some embodiments, when C is present, C comprises or consists of DOTA, Crown, NOPO, Macropa, lead-specific chelator (PSC), N-succinimidyl 3-(tri-n- butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

[0044] In some embodiments, when R is present, R comprises or consists of Ac-225, Cu- 64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-0 203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

[0045] In certain embodiments, when present, the linker is attached to the N-terminus of the polypeptide. In certain embodiments, the C-terminal amino acid of the polypeptide is not a cysteine. In some embodiments, when present, the chelator is attached to either the IPTS / 128722251.1 Page 6 of 337Docket No.: AKT-031WO polypeptide or the linker. In some embodiments, when present, the radionuclide is attached to the chelator.

[0046] In some embodiments, the polypeptide comprises at least one disulfide bridge.

[0047] In some embodiments, the polypeptide comprises at least two disulfide bridges. 5

[0048] In some embodiments, the composition and / or polypeptide thereof selectively binds to Nectin-4 or a portion thereof.

[0049] In certain embodiments, the polypeptide has a binding affinity for Nectin-4 or a portion thereof of 10 pM to 200 nM, 10 pM to 100 nM, or 10 nM to 100 nM, in vivo, ex vivo, or in vitro and / or as measured in a cell-based assay. 0

[0050] In some embodiments, the polypeptide has a binding inhibition constant of no greater than 100 nM.

[0051] In one aspect, the disclosure provides a composition comprising a polypeptide- drug conjugate, comprising a polypeptide and at least one drug moiety, wherein the polypeptide comprises an amino acid sequence having at least 90% identity to at least 445 amino acids a polypeptide having an amino acid sequence set forth in any one of SEQ ID NOs: 3-158, 162-208, or 212-237.

[0052] In certain embodiments, the drug moiety is selected from a V-ATPase inhibitor, a pro-apoptotic agent, a Bcl2 inhibitor, an MCL1 inhibitor, a HSP90 inhibitor, an IAP inhibitor, an mTor inhibitor, a microtubule stabilizer, a microtubule destabilizer, an 0 auristatin, a dolastatin, a maytansinoid, a MetAP (methionine aminopeptidase), an inhibitor of nuclear export of proteins CRMl, a DPPIV inhibitor, proteasome inhibitors, inhibitors of phosphoryl transfer reactions in mitochondria, a protein synthesis inhibitor, a kinase inhibitor, a CDK2 inhibitor, a CDK9 inhibitor, a kinesin inhibitor, an HDAC inhibitor, a DNA damaging agent, a DNA alkylating agent, a DNA intercalator, a DNA minor groove5 binder, a DHFR inhibitor, a topoisomerase inhibitor, an auristatin (e.g., monomethyl auristatin E), and an immunotoxin.

[0053] In one aspect, the disclosure provides a composition comprising an isolated compound or pharmaceutically acceptable salt thereof comprising an optional linker (L), and one or more of a polypeptide (M), chelator (C) or radionuclide (R), wherein M has an amino0 acid sequence comprising any one of SEQ ID NOs: 3-158, 161-168, 171-208, 212-215, or 216-237, including amino acid substitutions as set forth in Table 1C, Table 1D, Table 2C, Table 2D, Table 2E, Table 2F, or Table 2G.

[0054] In another aspect, the disclosure provides a composition comprising, a compound designed to bind to Nectin-4, which compound comprises or consists of a polypeptide having IPTS / 128722251.1 Page 7 of 337Docket No.: AKT-031WO an amino acid sequence comprising any one of SEQ ID NOs: 3-158, 161-168, 171-208, 212- 215, or 216-237, including amino acid substitutions as set forth in Table 1C, Table 1D, Table 2C, Table 2D, Table 2E, Table 2F, or Table 2G, and further comprises a modified N and / or C-terminus. 5

[0055] In certain embodiments, the modified N-terminus comprises one or more of an NH2-, Acetyl-, PEGn-, wherein n=0-10, DOTA-, or Biotin-. In some embodiments, the C terminus comprises an -NH2 or an -OH. In some embodiments, the polypeptide selectively binds to Nectin-4 or a portion thereof. In some embodiments, the polypeptide has a binding affinity of stronger than about 100 nM to Nectin-4, or a portion thereof, in vivo or in a cell-0 based assay.

[0056] In one aspect, the disclosure provides a compound comprising a miniprotein having an amino acid sequence with 90% identity to SEQ ID NO: 195, and further comprising one or more additional components according to a formula M-L-C-R, wherein L is a linker, C is a chelator, and R is a radionuclide. 5

[0057] In some embodiments, L comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, any linker set forth in Table 2A, or (Gly)n-(gGlu)n- or0 (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof. In some embodiments, C comprises or consists of DOTA, Crown, NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB). In some embodiments, R comprises or consists of Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-5 135, Ce-134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At- 211.

[0058] In one aspect, the disclosure provides a compound comprising a miniprotein 90% identical to at least 40 amino acids of the amino acid sequence of SEQ ID NO: 195, wherein the N and / or C-terminus comprise between one and thirty additional amino acids, and / or0 wherein the C-terminus comprises one fewer amino acids or up to 30 additional amino acids, provided that the entire miniprotein is no greater than about 100 amino acids in length.

[0059] In one aspect, the disclosure provides a method of improving binding affinity strength of a polypeptide to Nectin-4, the improvement comprising modifying four amino IPTS / 128722251.1 Page 8 of 337Docket No.: AKT-031WO acid residues of a polypeptide, which polypeptide has at least 44 amino acids in length and has substitutions at positions corresponding to 12, 21, 26, and 32 of SEQ ID NO: 78, wherein the substitutions correspond to K12A, Y21Q, S26Kme3, and G32A.

[0060] In some embodiments, the disclosure provides a pharmaceutical composition 5 comprising a polypeptide or compound as provided herein; and a pharmaceutically acceptable excipient.

[0061] In one aspect, the disclosure provides a method of treating cancer, the method comprising administering to a subject in need thereof, a composition comprising a conjugate comprising a polypeptide having at least 90% identity to at least 40 amino acids of an amino0 acid sequence as set forth in any one of SEQ ID NOs: 3-158, 161-168, 171-208, 212-215, or 216-237 and a radionuclide.

[0062] In some embodiments, the radionuclide is associated with the polypeptide with a linker and / or chelator according to a formula M-L-C-R, wherein M is the polypeptide, L is a linker, C is a chelator, and R is the radionuclide. In some embodiments, the polypeptide has5 an amino acid sequence comprising or consisting of SEQ ID NO: 195 or SEQ ID NO: 200.

[0063] In some embodiments, L comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF)0 linker, a caproleic acid linker, any linker set forth in Table 2A, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof. In some embodiments, C comprises or consists of DOTA, Crown, NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB). In some embodiments, R5 is Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I- 131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

[0064] In certain embodiments, R is a therapeutic agent and / or an imaging agent. In some such embodiments, R is Cu-64, Ga-68, Lu-177, In-111, Cu-67, La-132, or F-18.

[0065] In one aspect, the disclosure provides a method of reducing kidney cell uptake of0 a composition comprising administering to a subject a Nectin-4 binding protein having an amino acid sequence comprising at least one modified lysine residue at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the modification comprises at least small alkyl group attached to the nitrogen of the lysine side chain, optionally comprising a monomethyl, dimethyl, trimethyl, or isopropyl group and the reduction is as IPTS / 128722251.1 Page 9 of 337Docket No.: AKT-031WO compared to administration to the subject or a control subject an otherwise identical composition but not comprising the modified lysine residue at the position corresponding to X12 and / or X26.

[0066] In another aspect, the disclosure provides a method of treating cancer, the 5 improvement comprising administering a composition comprising a Nectin-4 binding protein having an amino acid sequence comprising at least one modified lysine residue at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the modification comprises at least one carbon attached to the nitrogen of the lysine side chain, optionally comprising a methyl, dimethyl, trimethyl, or isopropyl group as compared to a composition not comprising0 a modified lysine residue at a position corresponding to X12 and / or X26.

[0067] In one aspect, the disclosure provides a method of treating a subject with refractory or recurrent cancer comprising administering a composition, compound, or pharmaceutical composition as provided herein, wherein the treatment treats the cancer.

[0068] In one aspect, the disclosure provides a method of improving biodistribution of a5 pharmaceutical composition for a Nectin-4 positive population of cancer cells in a subject having a Nectin-4-positive cancer, comprising contacting the population with a polypeptide that has a modified lysine at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the lysine is modified by adding at least one small alkyl group to a lysine side chain and wherein the biodistribution is improved as compared to contacting the population0 without the modified lysine at a position corresponding to X12 and / or X26 of SEQ ID NO: 195.

[0069] In another aspect, the disclosure provides a method of diagnosing presence of a Nectin-4 positive population of cancer cells comprising:

[0070] contacting a population of cells with a composition, compound, or pharmaceutical5 composition as provided herein; detecting the presence of the composition, compound, or pharmaceutical composition of step (a) by measuring a signal; and comparing the detection in step (b) to a control signal; and diagnosing cancer if the composition, compound, or pharmaceutical composition of step (a) is detected above the control.

[0071] In some embodiments, the contacting is performed by administering to a subject0 in need thereof. In some embodiments, the administering is intravenous or subcutaneous. In some embodiments, the contacting is outside of the subject, optionally in vitro with a biopsy sample. IPTS / 128722251.1 Page 10 of 337Docket No.: AKT-031WO

[0072] In one aspect, the disclosure provides a method of treating a cancer in a subject using an immunotherapy, the method comprising administering to the subject a composition comprising a composition, compound, or pharmaceutical composition as provided herein.

[0073] In another aspect, the disclosure provides a use of a composition, compound, or 5 pharmaceutical composition as provided herein to treat cancer in a subject.

[0074] In one aspect, the disclosure provides a method of treating a subject in need thereof comprising administering to the subject in need thereof a composition, compound, or pharmaceutical composition as provided herein.

[0075] In some embodiments, the subject is diagnosed as having cancer. In some0 embodiments, a cancer cell from the subject expresses Nectin-4, or a portion thereof. In some embodiments, the expression of Nectin-4 is higher in the cancer cell than in a non-cancer cell, which expression can be measured by protein and / or nucleic acid levels.

[0076] In some embodiments, the composition, compound, or pharmaceutical composition is not taken up and / or retained in the kidney as compared to a compound that5 does not comprise a composition, compound, or pharmaceutical composition as provided herein. In some embodiments, the composition, compound, or pharmaceutical composition is internalized in a cell expressing human Nectin-4.

[0077] In some embodiments, the cancer is selected from breast cancer, ovarian cancer, melanoma, pancreatic cancer, peripheral neuroma, glioblastoma, adrenocortical carcinoma,0 AIDS-related lymphoma, anal cancer, urothelial cancer, bladder cancer, meningioma, glioma, astrocytoma, cervical cancer, chronic myeloproliferative disorders, colon cancer, endometrial cancer, ependymoma, esophageal cancer, Ewing’s sarcoma, extracranial germ cell tumors, extrahepatic bile duct cancer, gallbladder cancer, gastric cancer, gastrointestinal carcinoid tumors, gestational trophoblastic tumors, hairy cell leukemia, Hodgkin lymphoma,5 non-Hodgkin lymphoma, hypopharyngeal cancer, islet cell carcinoma, Kaposi sarcoma, laryngeal cancer, leukemia, lip cancer, oral cavity cancer, liver cancer, male breast cancer, malignant mesothelioma, medulloblastoma, Merkel cell carcinoma, metastatic squamous neck cell carcinoma, multiple myeloma and other plasma cell neoplasms, mycosis fungoides and Sezary syndrome, myelodysplastic syndromes, nasopharyngeal cancer, neuroblastoma,0 non-small cell lung cancer, small cell lung cancer, head and neck cancer, skin cancer, oropharyngeal cancer, bone cancers, including osteosarcoma and malignant fibrous histiocytoma of bone, paranasal sinus cancer, parathyroid cancer, penile cancer, pheochromocytoma, pituitary tumors, prostate cancer, rectal cancer, renal cell cancer, retinoblastoma, rhabdomyosarcoma, salivary gland cancer, small intestine cancer, soft tissue IPTS / 128722251.1 Page 11 of 337Docket No.: AKT-031WO sarcoma, supratentorial primitive neuroectodermal tumors, pineoblastoma, testicular cancer, thymoma, thymic carcinoma, thyroid cancer, transitional cell cancer of the renal pelvis and ureter, urethral cancer, uterine sarcoma, vaginal cancer, vulvar cancer, and Wilms tumor and other childhood kidney tumors. 5

[0078] In some embodiments, the composition, compound, or pharmaceutical composition is administered intravenously or subcutaneously.

[0079] In one aspect, the disclosure provides a method of targeting cancer cells expressing Nectin-4, the method comprising: determining or having determined a level of expression of Nectin-4 in a population of cancer cells; administering to a subject in need0 thereof a composition comprising a composition, compound, or pharmaceutical composition as provided herein, wherein the polypeptide of the composition, compound, or pharmaceutical composition is designed to specifically bind to human Nectin-4 and (iii) wherein the composition, compound, or pharmaceutical composition is attached to the surface and / or internalized into one or more Nectin-4 expressing cancer cells. 5

[0080] In some embodiments, the subject is treated after the administering as compared to prior to the administering.

[0081] In one aspect, the disclosure provides a method of targeting a population of cancer cells expressing Nectin-4, the improvement comprising contacting the population with a composition, compound, or pharmaceutical composition as provided herein, wherein X120 and / or X26 comprise a lysine with at least one additional small alkyl group attached to the nitrogen in the side chain, wherein the composition is taken up less by kidney cells than in a composition comprising a polypeptide that does not have a small alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26, wherein, optionally, the small alkyl group is part of a monomethyl, dimethyl, trimethyl, or isopropyl group. 5

[0082] In one aspect, the disclosure provides a conjugate comprising: a polypeptide (M) that specifically binds to Nectin-4; a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is Actinium-225. 0

[0083] In one aspect, the disclosure provides a conjugate comprising: a polypeptide (M) that specifically binds to Nectin-4; a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is Copper-64. IPTS / 128722251.1 Page 12 of 337Docket No.: AKT-031WO

[0084] In one aspect, the disclosure provides a conjugate comprising: a polypeptide (M) that specifically binds to Nectin-4; a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is 5 Gallium-68.

[0085] In another aspect, the disclosure provides a conjugate comprising: a polypeptide (M) that specifically binds to Nectin-4; a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is0 Indium-111.

[0086] In one aspect, the disclosure provides a conjugate comprising: a polypeptide (M) that specifically binds to Nectin-4; a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is5 Lead-212.

[0087] In another aspect, the disclosure provides a conjugate comprising: a polypeptide (M) that specifically binds to Nectin-4; a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is0 Lutetium-177.

[0088] In one aspect, the disclosure provides a conjugate comprising: a miniprotein (M) that specifically binds to Nectin-4; an N-terminal modification, conjugated to (M) through an optional linker (L), wherein (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and the N-terminal modification comprises a biotin. 5

[0089] In some embodiments, M of the conjugate has an amino acid sequence comprising any one of the amino acid sequences set forth in SEQ ID NOs: 3-158, 161-168, 171-208, or 212-215. In some embodiments, the amino acid sequence has at least 90% identity to that of at least 40 amino acids of SEQ ID NO: 176, wherein X2 is E or D; X6 is E or Q; X9 is T or A; X10 is A or G; X12 is A, Kme3, Kme2, Kme, Kipr or K; X13 is R or0 (Cit) X17 is G or A; X21 is Q, Y, or E; X24 is Q or K; X25 is A or K; X26 is Kme3, Kme2, Kme, K, Kipr, or S; X28 is Q or K; X29 is Y or K; X30 is L or V; X32 is A, G, or D; X41 is N or K; and X45 is S or absent.

[0090] In certain embodiments, M has an amino acid sequence comprising or consisting of SEQ ID NO: 195. IPTS / 128722251.1 Page 13 of 337Docket No.: AKT-031WO

[0091] In certain embodiments, M has an amino acid sequence comprising or consisting of SEQ ID NO: 200.

[0092] In one aspect, the disclosure provides an isolated polynucleotide comprising one or more nucleic acid sequences encoding a polypeptide selected from any one of SEQ ID 5 NOs: 3-158, 161-208, and 212-215; or a nucleic acid sequence encoding a polypeptide comprising at least 90%, 95%, 96%, 97%, 98%, 99% or greater identity to any one of SEQ ID NOs: 3-158, 161-168, 171-208, or 212-215.

[0093] In some embodiments, the disclosure provides a vector comprising an isolated polynucleotide provided herein. In some embodiments, the disclosure provides a host cell0 transformed with an isolated polynucleotide provided herein or a vector provided herein.

[0094] In one aspect, the disclosure provides a method of evaluating locations of one or more populations of cancerous cells in a subject, the method comprising administering to the subject a composition, compound, or pharmaceutical composition as provided herein and detecting to determine location of the composition in the subject. 5

[0095] In one aspect, the disclosure provides a method of decreasing kidney uptake of a composition administered to detect and / or treat one or more populations of cancer cells, the improvement comprising administering to a subject in need thereof a composition, compound, or pharmaceutical composition as provided herein, wherein X12 and / or X26 comprise a lysine with at least one additional small alkyl group attached to the nitrogen in the0 side chain, wherein the composition is taken up less by kidney cells than in a composition comprising a polypeptide that does not have a small alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26, wherein, optionally, the small alkyl group is part of a monomethyl, dimethyl, trimethyl, or isopropyl group.

[0096] In some embodiments, the detecting comprises an imaging procedure allows for5 selecting subjects, monitoring subjects, and / or treating subjects with a therapeutic comprising a miniprotein designed to bind to Nectin-4 expressed on one or more cancer cells in the one or more populations of cancer cells. In some embodiments, the therapeutic comprises a composition, compound, pharmaceutical composition, or conjugate as provided herein.

[0097] In one aspect, the disclosure provides a method of improving delivery of a0 radionuclide to a population of cancer cells in a subject, the method comprising administering a composition, compound, pharmaceutical composition, or conjugate as provided herein, wherein the amino acid sequences of the polypeptide comprise amino acids corresponding to positions X12 and / or X26 of SEQ ID NO: 195, and wherein X12 and / or X26 comprise a lysine with at least one additional small alkyl group attached to the nitrogen IPTS / 128722251.1 Page 14 of 337Docket No.: AKT-031WO in the side chain, wherein uptake by kidney cells is less than with a polypeptide having an amino acid sequence that does not comprise an additional small alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26.

[0098] In some embodiments, the small alkyl group comprises a monomethyl, dimethyl, 5 trimethyl, or isopropyl group.

[0099] In one aspect, the disclosure provides a method of treating an individual with cancer, the improvement comprising reducing one or more off-target effects or toxicity measures by administering composition, compound, pharmaceutical composition, or conjugate as provided herein, wherein the amino acid sequences of the polypeptide comprise0 amino acids corresponding to positions X12 and / or X26 of SEQ ID NO: 195, and wherein X12 and / or X26 comprise a lysine with at least one additional small alkyl group attached to the nitrogen in the side chain, wherein uptake by kidney cells is less than with a polypeptide having an amino acid sequence that does not comprise an additional small alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26. 5

[0100] In another aspect, the disclosure provides a method of treating an individual with cancer, the improvement comprising achieving a reduction in concentration of R in a kidney tissue in the presence of composition, compound, pharmaceutical composition, or conjugate as provided herein, wherein the amino acid sequences of the polypeptide comprise amino acids corresponding to positions X12 and / or X26 of SEQ ID NO: 195, and wherein X120 and / or X26 comprise a lysine with at least one additional small alkyl group attached to the nitrogen in the side chain, wherein uptake by kidney cells is less than with a polypeptide having an amino acid sequence that does not comprise a small alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26. as compared to the concentration of R in the kidney tissue in the absence the composition, compound, 5 pharmaceutical composition, or conjugate.

[0101] In some embodiments, the reduction in concentration of R in the kidney tissue is measured by urine output of R as measured by percent of administered radiation recovered or by detection as measured by a cell-based in vitro assay, or an in vivo detection assay.

[0102] In some embodiments, the administration of the composition can be repeated at0 least 2, 3, 4, 5, 6, or 7 times more in the presence of the composition having 90% identity to at least 40 amino acids of SEQ ID NO: 195 including a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO: 195 than in the presence of an A or K at positions corresponding to X12 and / or X26. IPTS / 128722251.1 Page 15 of 337Docket No.: AKT-031WO

[0103] In one aspect, the disclosure provides a method of reducing uptake by a kidney tissue of a composition, the improvement comprising administering a composition comprising (a) a radionuclide therapeutic comprising at least a polypeptide and a radionuclide (R); wherein the polypeptide has at least 90% identity to 40 amino acids of SEQ 5 ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO: 195, such that in the presence of the modified lysine, the radionuclide is less concentrated in the kidney tissue than in the absence of the polypeptide.

[0104] In another aspect, the disclosure provides a method comprising administering to a subject in need thereof a compound that binds to Nectin-4 and includes one or two modified0 lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195, wherein administration of the compound having a miniprotein with the one or two modified lysines reduces one or more off target effects, toxicity grades, and / or uptake and / or retention in a kidney tissue as compared to a compound having an alanine or unmodified lysine at a position corresponding to X12 and an unmodified lysine at a position corresponding to X26. 5

[0105] In one aspect, the disclosure provides a method of treating an individual having or suspected of having a Nectin-4-positive cancer, the method comprising administering to the individual: a means for blocking uptake and / or retention of a radiotherapeutic to kidney tissue, and a linker, a chelator, and a radionuclide.

[0106] In some embodiments, the means for blocking uptake and / or retention of a0 radiotherapeutic to kidney tissue binds to Nectin-4 and includes one or two modified lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195 and / or has at least 90% identity to 40 amino acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO: 195.

[0107] In some embodiments, the means for blocking uptake and / or retention of a5 radiotherapeutic to kidney tissue binds to Nectin-4 and includes one or two modified lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195 and / or has at least 90% identity to 35 contiguous amino acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO: 195.

[0108] In some embodiments, the means for blocking uptake and / or retention of a0 radiotherapeutic to the kidney tissue blocks uptake and / or retention to the kidney tissue greater than as compared to the blocking of uptake and / or retention to the kidney tissue by a means that does not include one or two modified lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195 and / or has at least 90% identity to 40 amino IPTS / 128722251.1 Page 16 of 337Docket No.: AKT-031WO acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO: 195.

[0109] In some embodiments, the means for blocking uptake and / or retention of a radiotherapeutic to the kidney tissue blocks uptake and / or retention to the kidney tissue 5 greater than as compared to the blocking of uptake and / or retention to the kidney tissue by a means that does not include one or two modified lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195 and / or has at least 90% identity to 35 contiguous amino acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO: 195. 0

[0110] In some embodiments, the means for blocking uptake and / or retention of a radiotherapeutic to the kidney tissue is a radiotherapeutic. In some embodiments, the radiotherapeutic is targeted to a tumor or a population of cancer cells. In some embodiments, the radiotherapeutic targeted to the tumor or the population of cancer cells is at a greater concentration than in the absence of the means for binding to kidney tissue. In some5 embodiments, the radiotherapeutic comprises a polypeptide that targets Nectin-4.

[0111] In some embodiments, the radiotherapeutic comprises or consists of a compound selected from C3-C293 or C298-C307. In some embodiments, the radionuclide of the radiotherapeutic is selected from Ac-225, Cu-64, Ga-68, In-111, Lu-177, or Pb-212.

[0112] In one aspect, the disclosure provides a kit comprising a polypeptide and0 instructions for use, wherein the polypeptide has an amino acid sequence as set forth in a polypeptide of any one of a composition, compound, pharmaceutical composition, or conjugate as provided herein.

[0113] In some embodiments, the kit further comprises one or more of a linker, chelator, and radionuclide. In some embodiments, the linker comprises or consists of a polyethylene5 glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N- maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof. In0 some embodiments, the chelator comprises or consists of DOTA, NOPO, Crown, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), or N- succinimidyl 3-trimethylstannylbenzoate (MeSTB). IPTS / 128722251.1 Page 17 of 337Docket No.: AKT-031WO

[0114] In some embodiments, prior to use, the compound is labeled with a radionuclide, wherein the radionuclide is chelated to the chelator to produce a composition with a formula M-L-C-R.

[0115] In some embodiments, the radionuclide is selected from Ac-225, Cu-64, Ga-68,5 Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th- 232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211. In some embodiments, the radionuclide is Ac-225, Cu-64, Ga-68, In-111, Lu-177, or Pb-212.

[0116] In some embodiments, if the polypeptide has an amino acid comprising any of those set forth in any one of SEQ ID NOs: 83, 85, 93, 99, 134, 138, 145, 155, 161-176, 195,0 or 200 the polypeptide further comprises a linker, wherein the linker is PEG4, and a chelator, wherein the chelator is DOTA. In some embodiments, when present, the linker is attached to the N-terminus amino acid of the polypeptide. In some embodiments, the C-terminal amino acid of the polypeptide is not cysteine. In some embodiments, when present, the chelator is attached to either the polypeptide or the linker. In some embodiments, when present, the5 radionuclide is attached to the chelator. In some embodiments, when present, the radionuclide is attached to the N-terminus amino acid of the polypeptide. BRIEF DESCRIPTION OF FIGURES

[0117] FIGs.1A and 1B are fitted sensorgrams (SPR) of an exemplary Nectin-4 peptide binding to mouse and human Nectin-4, respectively. 0

[0118] FIGs.2A and 2B are fitted sensorgrams (SPR) of an exemplary Nectin-4 peptide binding to mouse and human Nectin-4, respectively.

[0119] FIGs.3A and 3B are fitted sensorgrams (SPR) of an exemplary conjugate comprising an exemplary Nectin-4 peptide binding to mouse and human Nectin-4, respectively. 5

[0120] FIGs.4A and 4B are graphs showing association (FIG.4A) and dissociation (FIG.4B) kinetics for an exemplary compound comprising a radioconjugate miniprotein provided herein, on a human Nectin-4-expressing cancer line.

[0121] FIGs.5A and 5B are graphs showing association (FIG.5A) and dissociation (FIG.5B) kinetics of an exemplary compound comprising a radioconjugate miniprotein0 provided herein, on a human Nectin-4-expressing cancer line.

[0122] FIGs.6A and 6B are graphs showing internalization of an exemplary radioconjugate in HT-1376 (FIG.6A) and MCF7 (FIG.6B) cell lines at 37oC and 4oC. TB = total binding, NSB = non-specific binding. IPTS / 128722251.1 Page 18 of 337Docket No.: AKT-031WO

[0123] FIG.7 is a graph showing thermostability of an exemplary compound, expressed as percentage of parent remaining over 60 minutes while heated at 75°C.

[0124] FIG.8 is a bar graph of the percent uptake of exemplary miniproteins tested at 20 ^M in a proximal tubule epithelial cell assay vs 20 ^M control peptide set at 100%. 5

[0125] FIG.9A is a graph showing tumor volume (mm3) over time in mice treated with 500 nCi of225Ac-C251 (triangles) , 1000 nCi of225Ac-C251 (squares) or vehicle (circles). Mice were dosed at Day 0. FIG.9B is a graph showing body weight as a percentage relative to initial body weight over time of mice undergoing the treatments described in FIG.9A.

[0126] FIG.9C is a graph showing proportion of survival in a mouse xenograft model0 over an 8-week period. Xenografts were generated with HT-1376-Parental Nectin-4- Expressing Cells (P) or HT1376-Nectin-4-Overexpressing (OE) cells. Mice were treated with vehicle (P, closed circles; OE, closed triangles) or 1000 nCi of225Ac-C251 (P, open triangles; OE, open squares).

[0127] FIG.10A is a graph showing tumor volume over time in mice treated with 5005 nCi of225Ac-C244 (triangles), 1000 nCi (squares) of225Ac-C244 or vehicle (circles). Mice were dosed at Day 0. FIG.10B is a graph showing body weight as a percentage relative to initial body weight over time of mice undergoing the treatments described in FIG.10A.

[0128] FIG.11A is a graph showing tumor volume over time in mice treated with 500 nCi of225Ac-C260 (triangles), 1000 nCi of225Ac-C260 (squares), or vehicle (circles). Mice0 were dosed at Day 0. FIG.11B is a graph showing body weight as a percentage relative to initial body weight over time of mice undergoing the treatments described in FIG.11A.

[0129] FIG.12 is an exemplary HPLC trace for exemplary miniprotein C251, showing the milli-absorbance unit (mAU) over time (min).

[0130] FIG.13 is an exemplary mass spectrum for exemplary miniprotein C251. 5

[0131] FIGs.14A-14C are graphs showing exemplary UPLC-MS data for C251.

[0132] FIG.15 is a graph showing kidney uptake (%ID / g) comparisons for111In- radiolabeled miniproteins (C109, C244, and C251).

[0133] FIG.16 is a graph showing reduction in cellular uptake of exemplary target- binding miniprotein compound, C294, when combined with an exemplary decoy, C296, in0 vitro. The bar graph depicts percent uptake of an exemplary Nectin-4-targeting miniprotein (C294) alone / without a decoy peptide (20 μM) or in combination with a 20-fold molar excess of an exemplary decoy (C296). Error bars represent standard error of the mean (SEM).

[0134] FIGs.17A-17D are graphs showing in vivo kidney (FIGs.17A and 17C) or tumor (FIGs.17B and 17D) retention, in an exemplary mouse xenograft model, shown as %ID / g IPTS / 128722251.1 Page 19 of 337Docket No.: AKT-031WO from 0.25-32 h post-injection of an111In-labeled exemplary Nectin-4-targeting miniprotein conjugate (111In-C109 in FIGs.17A and 17B;111In-C251 in FIGs.17C and 17D) alone / without a decoy or co-administered with a 1,000-fold molar excess of an exemplary decoy (C295 in FIGs.17A and 17B; C296 in FIGs.17C and 17D). FIG.17A is a line graph5 showing %ID / g in kidney of an exemplary Nectin-4-targeting miniprotein conjugate (111In- C109) alone / without a decoy (circles) or in combination with an exemplary decoy (C295; squares). FIG.17B is a line graph showing %ID / g in tumor of an exemplary Nectin-4- targeting miniprotein conjugate (111In-C109) alone / without a decoy (circles) or in combination with an exemplary decoy (C295; squares). FIG.17C is a line graph showing0 %ID / g in kidney of an exemplary Nectin-4-targeting miniprotein conjugate (111In-C251) alone / without a decoy (circles) or in combination with an exemplary decoy (C296; squares). FIG.17D is a line graph showing %ID / g in tumor of an exemplary Nectin-4-targeting miniprotein conjugate (111In-C251) alone / without a decoy (circles) or in combination with an exemplary decoy (C296; squares). 5

[0135] FIGs.18A and 18B are graphs showing in vivo tumor volume (mm3; FIG.18A) and bodyweight (% of initial weight; FIG.18B) measurements in an exemplary mouse xenograft model, treated at Day 0 with: (i) vehicle (solid circles); (ii) an exemplary decoy (C296; 1 mg; 1000X of C251 dose, solid triangles); (iii) an225Ac-labeled exemplary Nectin- 4-targeting radionuclide conjugate (225Ac-C251; 1 mg; 1,000 nCi; open circles); or (iv) a0 combination of the exemplary decoy (C296; 1000X of C251 dose) and the exemplary Nectin- 4-targeting radionuclide conjugate (225Ac-C251; 1,000 nCi) (open triangles). In FIG.18A, the dotted line at 2,000 mm3marks the maximum tumor growth threshold for the pre-defined humane endpoint of experimental mice. In FIG.18B, the dotted line at 80% of initial body weight marks the body weight decrease threshold for the pre-defined humane endpoint for5 the experimental mice. Error bars represent standard error of the mean (SEM).

[0136] FIGs.19A and 19B are graphs showing in vivo tumor volume (mm3; FIG.19A) and body weight (% of initial weight; FIG.19B) measurements in an exemplary mouse xenograft model, treated at Day 0 with: (i) vehicle (circles; single dose); an225Ac-labeled exemplary Nectin-4-targeting radionuclide conjugate (225Ac-C251) at two different doses0 ((ii) 0.5 mg; 1,000 nCi; single dose; triangles, or (iii) 1 mg; 2,000 nCi; single dose; inverted triangles); or (iv) an anti-Nectin-4 antibody-drug conjugate (ADC) control (enfortumab vedotin (EV); 3 mg / kg; three doses; squares). Black arrowheads under the x-axis indicate dosing of225Ac-C251 at Day 0. Gray arrowheads under the x-axis indicate dosing of EV at Days 0, 8, and 15. In FIG.19A, the dotted line at 1,500 mm3marks the maximum tumor IPTS / 128722251.1 Page 20 of 337Docket No.: AKT-031WO growth threshold for the pre-defined humane endpoint of experimental mice. In FIG.19B, the dotted line at 80% of initial body weight marks the body weight decrease threshold for the pre-defined humane endpoint of experimental mice. Error bars represent standard error of the mean (SEM). 5

[0137] FIGs.20A and 20B are graphs showing in vivo tumor volume (mm3; FIG.20A) and body weight (% of initial weight; FIG.20B) measurements in an exemplary patient- derived mouse xenograft model, treated at Day 0 with: (i) vehicle (circles); (ii) an225Ac- labeled exemplary Nectin-4-targeting radionuclide conjugate (225Ac-C251; 1 mg; 2,000 nCi; single dose; inverted triangles), or (iii) an anti-Nectin-4 ADC control (enfortumab vedotin0 (EV); 3 mg / kg; three doses; squares). Black arrowheads under the x-axis indicate dosing of 225Ac-C251 at Day 0. Gray arrowheads under the x-axis indicate dosing of EV at Days 0, 8, and 15. Error bars represent standard error of the mean (SEM).

[0138] FIG.21 is a graph showing high binding affinity of a biotin-labeled exemplary Nectin-4-targeting miniprotein (C253) to endogenous Nectin-4 expressed on HT-13765 human urothelial cancer cells in the presence of a europium-labeled Nectin-4 binder (C307). The dose-response curve depicts fluorescence units as a measurement of the binding of biotin-labeled exemplary Nectin-4-binding miniprotein C253, evaluated over 12 concentrations ranging from 28 pM to 5 μM (x-axis; expressed in log M).

[0139] FIG.22 is a graph showing the plasma profile and clearance of an indium-labeled0 exemplary Nectin-4-targeting conjugate (nat.In-C251) intravenously administered at 0.03 mg / kg (circles), 0.1 mg / kg (squares), or 0.3 mg / kg (diamonds) in rats, compared to FITC- Sinistrin, (FS; inverted triangles), a molecule known to be cleared at the glomerular filtration rate (GFR), at 62.4 mg / kg. The plot shows the concentration ofnat.In-C251 and FITC- Sinistrin over a 2 h period. 5

[0140] FIGs.23A and 23B are graphs showing selective target binding of a biotin- labeled exemplary Nectin-4-targeting miniprotein (C253), as measured by flow cytometry (FIG.23A), and a dose-response curves (FIG.23B) in Nectin-4-expressing (HT-1376- Parental or “HT-1376-P”) or knockout (HT-1376-KO) cells. FIG.23A shows the percentage of cells normalized to the mode (on y-axis) identified to express Nectin-4 after incubation0 with 100 nM of C253, as measured by the mean fluorescence intensity (MFI; on x-axis). FIG.23B shows the difference in mean fluorescence intensity (Delta MFI; y-axis) of HT- 1376-P (circles) and HT-1376-KO (inverted triangles) cells incubated with C253 and cells incubated with vehicle, as a measurement of Nectin-4 binding at 0.001 nM, 0.01 nM, 0.1 nM, 1 nM, 10 nM, 100 nM, and 1000 nM of C253 (on x-axis). IPTS / 128722251.1 Page 21 of 337Docket No.: AKT-031WO

[0141] FIGs.24A and 24B are graphs showing in vivo retention of111In-labeled exemplary Nectin-4-targeting miniprotein conjugates111In-C109 (FIG.24A) and111In-C251 (FIG.24B) in kidney (squares) and tumor (circles) in an exemplary mouse isogenic xenograft model observed from 10 min through 22 h post-injection. 5 DETAILED DESCRIPTION

[0142] Among other things, the disclosure provides compositions and methods of use thereof. In some embodiments, a composition selectively binds to a target (e.g., Nectin-4). In some embodiments, the target is on a tumor cell. In some such embodiments, the tumor cell is part of a population of tumor cells (e.g., a solid tumor). In some embodiments, the tumor0 cells are circulating (e.g., a hematologic cancer, circulating tumor cells, etc.). In some embodiments the composition comprises one or more additional agents (e.g., a chelator, a radionuclide), which agents may be used as therapeutics (e.g., a radionuclide to kill a cancer cell) wherein the therapeutic agent is selectively targeted to a cell, e.g., a cell expressing Nectin-4, e.g., a cancer cell expressing Nectin-4, by a miniprotein that is part of the 5 composition. In some embodiments the composition comprises one or more therapeutic agents (e.g., a chelator, a radionuclide), wherein the therapeutic agent is selectively targeted to a cell expressing Nectin-4 such that the Nectin-4-expressing cell is treated and cells not expressing Nectin-4 are not treated. The disclosure recognizes that a source of a problem in treating cells expressing a target (e.g., cancer cells) is that traditional therapies are not0 selective enough to specifically target cells (e.g., tumor cells) and to deliver a therapeutic in a way that minimizes damage to surrounding cells (e.g., non-tumor cells). Surrounding cells (e.g., as in one or more non-tumor tissues) may also express the target at lower amounts or levels than target cells. The present disclosure provides the insight that a combination of selective targeting with a specific therapeutic such as a chelator and / or radionuclide (e.g., an5 alpha emitter) provides an advantage over previously used therapeutics (e.g., antibodies, beta-emitters, etc.).

[0143] Furthermore, the disclosure provides the insight that even a therapeutic such as those provided herein is designed to be more specific for Nectin-4 and / or a tissue such as a tumor tissue), challenges can still arise. When Nectin-4 is expressed by a non-tumor cell0 and / or when a therapeutic (e.g., a radiotherapeutic) is taken up by an organ system, such as involved in clearance of systemically administered agents (e.g., kidney), efficacy can decrease and toxicity can increase. The disclosure contemplates that uptake to a tumor may be challenged by uptake, retention, and / or clearance by one or more non-target (e.g., non- IPTS / 128722251.1 Page 22 of 337Docket No.: AKT-031WO tumor) tissues. For example, kidney can play a role in clearance of administered therapeutics. In addition, such therapeutics can be taken up and / or retained in the kidney. For example, uptake of a therapeutic intended for a tumor can also be taken up, retained, and / or cleared by the kidney resulting in (1) faster clearance from a subject to whom it has been administered; 5 (2) reduced tumor targeting (including because therapeutic is taken up and / or retained in a non-target tissue), and / or cleared; and / or (3) non-target tissue (e.g., kidney, etc.) damage.

[0144] The disclosure recognizes that any or all of these challenges may be mitigated or prevented by combining administration of a Nectin-4 targeting therapeutic with administration of a decoy. In some embodiments, the decoy blocks uptake by a kidney of a0 composition comprising a polypeptide as provided herein (e.g., a radionuclide conjugate). Without wishing to be bound by theory, the disclosure contemplates that improvement in treatment efficacy is at least maintained while reducing damage to one or more non-tumor tissues (e.g., kidney) and, in some embodiments, treatment efficacy is improved while simultaneously reducing risk of harm or actual harm to non-tumor tissue (e.g., kidney tissue5 and / or renal system tissues such as ureters, bladder, etc.).

[0145] Unless otherwise defined herein, scientific and technical terms used in connection with the present disclosure shall have the meanings that are commonly understood by those of ordinary skill in the art. Furthermore, unless otherwise required by context, singular terms shall include the plural and plural terms shall include the singular. Generally, nomenclatures0 used in connection with, and techniques of, biochemistry, enzymology, molecular and cellular biology, microbiology, genetics and protein and nucleic acid chemistry and hybridization described herein are those well-known and commonly used in the art.

[0146] The methods and techniques of the present disclosure are generally performed according to conventional methods well known in the art and as described in various general5 and more specific references that are cited and discussed throughout the present specification unless otherwise indicated. See, e.g., Sambrook et al., Molecular Cloning: A Laboratory Manual, 2d ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989); Ausubel et al., Current Protocols in Molecular Biology, Greene Publishing Associates (1992, and Supplements to 2002); Harlow and Lane, Antibodies: A Laboratory Manual, Cold Spring0 Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1990); Wittrup and VanAntwerp, Fine Affinity Discrimination by Yeast Surface Display and Flow Cytometry, Biotechnol. Prog. 2002, (16) 31-37; C. Queen et al., A humanized antibody that binds to the interleukin 2 receptor, Proc. Natl. Acad. Sci. USA 1989, 86 (24) 10029-10033; Scheinberg DA and IPTS / 128722251.1 Page 23 of 337Docket No.: AKT-031WO McDevitt MR. Actinium-225 in targeted alpha-particle therapeutic applications. Curr Radiopharm.2011;4(4):306-320.

[0147] All publications, patents, and other references mentioned herein are hereby incorporated by reference in their entireties. In case of conflict, the present specification, 5 including definitions, will control. Materials, methods, and examples as disclosed herein are illustrative only and not intended to be limiting.

[0148] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this present disclosure pertains. Further, unless otherwise required by context, singular terms0 shall include the plural and plural terms shall include the singular. Generally, nomenclatures used in connection with, and techniques of, biochemistry, enzymology, molecular and cellular biology, microbiology, genetics and protein and nucleic acid chemistry and hybridization described herein are those well-known and commonly used in the art.

[0149] Throughout this specification and claims, the word “comprise” or variations such as5 “comprises” or “comprising,” will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0150] As used herein, ranges and amounts can be expressed as “about” a particular value or range, e.g., “about” one particular value, and / or to “about” another particular value. About also includes the exact amount. Hence “about 100 nucleotides” means “about 100 0 nucleotides” and also “100 nucleotides.” Given context, the term “about” as used herein also includes an amount that would be expected to be within experimental error. If “about” appears before a quantitative value, the present disclosure also includes the specific quantitative value itself, unless specifically stated otherwise. In such instances “about” can also refer to a ±10% variation from the nominal value unless otherwise indicated or inferred. 5 When values are expressed as approximations by use of the antecedent “about,” it is understood that the disclosure also contemplates embodiments that specify the particular values and ranges of values without the approximations.

[0151] As used herein, the singular forms “a,” “an” and “the” include plural referents unless context clearly dictates otherwise. Thus, for example, in some embodiments, reference0 to, e.g., decoys includes a plurality of decoys, a single decoy, etc.

[0152] As used herein, the expression “and / or” in connection with two or more recited objects includes individually each of the recited objects and the various combinations of two or more of the recited objects, unless otherwise understood from the context and use. IPTS / 128722251.1 Page 24 of 337Docket No.: AKT-031WO

[0153] Unless otherwise indicated, and as an example for all sequences described herein under the general format “SEQ ID NO:”, “nucleic acid comprising SEQ ID NO: 1” refers to a nucleic acid, at least a portion of which has either (i) the sequence of SEQ ID NO: 1, or (ii) a sequence complementary to SEQ ID NO: 1. The choice between the two is dictated by the 5 context. For instance, if the nucleic acid is used as a probe, the choice between the two is dictated by the requirement that the probe be complementary to the desired target.

[0154] As used herein, the term “administration” refers providing a composition to a subject or system. Administration to a subject may be by any appropriate route, dose and / or dose schedule. 0

[0155] As used herein, the term “affibody” refers to a subgenus of miniproteins. An affibody is a molecule derived from the Z-domain of staphylococcal protein A that consists of three alpha helices with 58 amino acids and has a molar mass of about 6 kDa. See, for exemplary details of affibody structures and uses, Orlova, A; Magnusson, M; Eriksson, T L; Nilsson, M; Larsson, B; Höidén-Guthenberg, I; Widström, C; Carlsson, J et al. (2006).5 “Tumor imaging using a picomolar affinity HER2 binding affibody molecule”, Cancer Res. 66 (8): 4339-48. Exemplary Affibody® Molecules are commercially available from Abcam Corp. Cambridge Mass. An affibody is stable at high temperatures and under acidic or alkaline conditions. Target specificity is obtained by randomization of 13 amino acids located in two alpha-helices involved in the binding activity of the parent protein domain0 (Feldwisch J, Tolmachev V.; (2012) Methods Mol Biol.899:103-26).

[0156] As used herein, the term “affinity maturation” generally refers to a process whereby successive changes to a sequence (e.g., successive mutations) are made and selection of the polypeptide sequences are performed to choose one or more sequences with increased affinity relative to the “starting” sequence or another sequence with less affinity as5 compared to one with greater affinity.

[0157] As used herein, the terms “amino acid sequence” and “polypeptide” refer to a polymer of amino acids connected by one or more peptide bonds. A polypeptide of the present disclosure encompasses both naturally occurring and non-naturally occurring proteins, and any fragments, portions, peptides, mutants, derivatives, and analogs thereof. A0 polypeptide may be monomeric or polymeric. Further, a polypeptide may comprise a number of different domains each of which has one or more distinct activities. A polypeptide may be fully or partially synthetic or otherwise modified (i.e., comprising one or more synthetically produced amino acids and / or modifications thereof). The term “peptide” may be used to IPTS / 128722251.1 Page 25 of 337Docket No.: AKT-031WO refer to a short polypeptide, such as one comprising fewer than about 70 amino acids (e.g., between about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or 70 amino acids).

[0158] As used herein, the term “anticalin” refers to a subgenus of miniproteins. An anticalin is an engineered protein derived from a lipocalin (Beste G, Schmidt FS, Stibora T, 5 Skerra A. (1999) Proc Natl Acad Sci U S A.96(5): 1898-903; Gebauer and Skerra (2009) Curr Opinion in Chemical Biology 13:245-255). Anticalins possess an eight-stranded b- barrel which forms a highly conserved core unit among the lipocalins and naturally forms binding sites for ligands by means of four structurally variable loops at the open end. Anticalins, although not homologous to the IgG superfamily, show features that so far have0 been considered typical for the binding sites of antibodies: (i) high structural plasticity as a consequence of sequence variation and (ii) elevated conformational flexibility, allowing induced fit to targets with differing shape.

[0159] As used herein, the term “attenuate” as used herein generally refers to a functional deletion, including a mutation, partial or complete deletion, insertion, or other variation made5 to a gene sequence or a sequence controlling the transcription of a gene sequence, which reduces or inhibits production of the gene product, or renders the gene product non- functional. In some instances, a functional deletion is described as a knockout mutation. Attenuation also includes amino acid sequence changes by altering the nucleic acid sequence, placing the gene under the control of a less active promoter, down-regulation, expressing0 interfering RNA, ribozymes or antisense sequences that target the gene of interest, or through any other technique known in the art. In one example, the sensitivity of a particular enzyme to feedback inhibition or inhibition caused by a composition that is not a product or a reactant (non-pathway specific feedback) is lessened such that the enzyme activity is not impacted by the presence of a compound. In other instances, an enzyme that has been altered to be less5 active can be referred to as attenuated.

[0160] As used herein, the term “avimer” refers to a subgenus of miniproteins. An avimer is a class of antibody mimetics which consist of two or more peptide sequences of preferably 30 to 35 amino acids each, which are derived from A-domains of various membrane receptors, and which are connected by linker peptides. Binding of target molecules occurs via0 the A-domain and domains with the desired binding specificity can be selected, for example, by phage display techniques. The binding specificity of the different A-domains contained in an avimer may but does not have to be identical (Weidle UH, et al., (2013), Cancer Genomics Proteomics; 10(4): 155-68). For further details see Nature Biotechnology 23(12), 1556 – 1561 (2005) and Expert Opinion on Investigational Drugs 16(6), 909-917 (June IPTS / 128722251.1 Page 26 of 337Docket No.: AKT-031WO 2007). As used herein, the term “binder” refers to a subgenus of miniprotein. A binder is characterized in that it comprises or consists of a polypeptide that is capable of binding or has known ability to engage and associate a target or a portion thereof. Binders generally comprise a cysteine-containing peptide comprising one or more disulfide bonds, though 5 some binders do not comprise cysteine-residues and / or disulfide bonds. Binders are preferably cleared rapidly from circulation when administered systemically to a mammalian subject. As will be understood, given context, reference to a binder may be or include its nucleic acid sequence or amino acid sequence encoding it. A binder may be provided, for instance, as a polynucleotide, polypeptide, using a vector, host cell, etc., and / or any 0 combination of modalities. A binder may be derived or manufactured using any method known to those of skill in the art. For instance, in some embodiments, a binder can be recombinant (i.e., produced using recombinant nucleic acids encoding a polypeptide). In some embodiments, a binder can be synthetic (e.g., synthesized such as using standard solid phase synthesis methods, such as solid phase peptide synthesis, known to those of skill in the5 art (see, e.g., Palomo, J. RSC Adv., 2014,4, 32658-32672) and described herein).

[0161] As used herein, the term “block” refers to preventing, slowing, suppressing, or otherwise reducing or decreasing uptake and / or retention of a compound into a tissue (e.g., a non-tumor tissue, e.g., a kidney tissue). In some embodiments, a decoy blocks, suppresses, reduces, or otherwise decreases uptake of a conjugate or compound of the disclosure into a0 non-tumor tissue, such as kidney tissue. In some embodiments, a decoy reduces retention of a compound (e.g., a radiotherapeutic compound, e.g., comprising a miniprotein) in a non-tumor tissue (e.g., kidney).

[0162] As used herein, the term “chelator” refers to any molecule or moiety that is capable of forming a complex (i.e., “chelates”) with a metal ion. Chelators generally have two or5 more unshared electron pairs that can be used to donate to a metal ion. Metal ions are usually coordinated to the chelator by two or more pairs of electrons.

[0163] As used herein, the term “conjugated” refers to the joining by covalent or noncovalent means of two compounds or agents.

[0164] As used herein, a “conservative amino acid substitution” is one in which an amino0 acid residue is substituted by another amino acid residue having a side chain (R group) with similar chemical properties (e.g., charge or hydrophobicity). In general, a conservative amino acid substitution will not substantially change the functional properties of a protein. In cases where two or more amino acid sequences differ from each other by conservative substitutions, the percent sequence identity or degree of homology may be adjusted upwards IPTS / 128722251.1 Page 27 of 337Docket No.: AKT-031WO to correct for the conservative nature of the substitution. Means for making this adjustment are well known to those of skill in the art. See, e.g., Pearson, 1994, Methods Mol. Biol. 24:307-31 and 25:365-89 (herein incorporated by reference). The following six groups each contain amino acids that are conservative substitutions for one another: 1) Serine (S), 5 Threonine (T); 2) Aspartic Acid (D), Glutamic Acid (E); 3) Asparagine (N), Glutamine (Q); 4) Arginine (R), Lysine (K); 5) Isoleucine (I), Leucine (L), Methionine (M), Alanine (A), Valine (V), and 6) Phenylalanine (F), Tyrosine (Y), Tryptophan (W).

[0165] As used herein the terms “cysteine-dense peptide” and “CDP” are used interchangeably and refer to a subgenus of miniproteins that generally comprise a high0 density of cysteines (e.g., at least one, two, three, four, or more cysteines in a span of about 10 to about 90 amino acids, or about 13 to 80 amino acids in a polypeptide). In some embodiments, such a CDP may comprise at least two independent folding domains. In some embodiments, the CDP comprises at least one, two, three, four, or more cysteine residues in a span of from about 10 to about 90 amino acid residues, preferably 13 to 80 amino acid5 residues. (pubmed.ncbi.nlm.nih.gov / 29483648 / ). In some embodiments, the CDP comprises a constrained distribution of cysteines, Cys-X[0–15]-Cys-X[0–15]-Cys-X[0–15]-Cys-X[0–15]-Cys- X[0–15]-Cys (wherein X represents any amino acid) (SEQ ID NO: 241).

[0166] As used herein, a “compound” refers at least to a miniprotein with an amino acid sequence. Compounds may include miniproteins with different modifications, such as a N-0 terminal modification or a C-terminal modification. In various embodiments, a “compound” can include a miniprotein and one or more additional elements, examples of which include a linker, a chelator, and / or a radionuclide. For example, a compound may include a miniprotein conjugated to a chelator and / or a radionuclide e.g., via a linker. As denoted herein, compounds are identified with a specific compound number e.g., “C1,” “C2,” C3”, etc.5 Different compounds may have different sequences. In various embodiments, different compounds may have the same sequence (e.g., assigned the same SEQ ID NO), but may have one or more of different modifications (e.g., different N-terminal or C-terminal modifications), different linkers, different chelators, and / or different radionuclides. N- and C- terminal modifications may include but not be limited to acetyl, acid, or amide (e.g., Acetyl,0 NH2, OH), such as provided in exemplary compounds and miniproteins of TABLE 2A. In some embodiments, a polypeptide according to the disclosure may have various modifications to its N-terminus (e.g., such as set forth in exemplary compounds in TABLE 2A), and can have an acid or amide group on its C-terminus (see, e.g., TABLE 2A). A given polypeptide having a particular amino acid sequence can have one or more N-terminal and / or IPTS / 128722251.1 Page 28 of 337Docket No.: AKT-031WO C-terminal differences without materially changing the utility or function of the polypeptide, such as for binding to Nectin-4 (e.g., for detection and / or treatment of cancer).

[0167] As used herein, the term “deletion” generally refers to the removal of one or more nucleotides from a nucleic acid molecule or one or more amino acids from a protein, the 5 regions on either side being joined together.

[0168] As used herein, the phrase “degenerate variant” of a reference nucleic acid sequence encompasses nucleic acid sequences that can be translated, according to the standard genetic code, to provide an amino acid sequence identical to that translated from the reference nucleic acid sequence. The term “degenerate oligonucleotide” or “degenerate0 primer” is used to signify an oligonucleotide capable of hybridizing with target nucleic acid sequences that are not necessarily identical in sequence but that are homologous to one another within one or more particular segments.

[0169] As used herein, the term “derived from,” with reference to a nucleic acid sequence refers to a nucleic acid sequence that has at least 85% sequence identity to a reference5 naturally occurring nucleic acid sequence from which it is derived. The term “derived from,” with reference to an amino acid sequence refers to an amino acid sequence that has at least 85% sequence identity to a reference naturally occurring amino acid sequence from which it is derived. The term “derived from” as used herein does not denote any specific process or method for obtaining the nucleic acid or amino acid sequence. For example, the nucleic acid0 or amino acid sequence can be chemically synthesized.

[0170] As used herein, the term “designed ankyrin repeat domain (DARPin)” refers to a subgenus of miniproteins. A DARPin is a peptide derived from Ankyrin which is a family of proteins that mediate attachment of integral membrane proteins to the cytoskeleton. A single ankyrin repeat is preferably a 33-residue motif consisting of two alpha-helices and a beta-5 turn. They can be engineered to bind different target antigens by randomizing residues in the first alpha-helix and a beta-turn of each repeat. Their binding interface can be increased by increasing the number of modules (a method of affinity maturation). For further details see J. Mol. Biol.332, 489-503 (2003), PNAS 100(4), 1700-1705 (2003) and J. Mol. Biol.369, 1015-1028 (2007) and US20040132028A1. DARPins typically provide a rigid interface and0 lack structural flexibility (Gebauer and Skerra, 2009).

[0171] As used herein, the term “domain” as used herein refers to a structure of a biomolecule that contributes to a known or suspected function of the biomolecule. Domains may be co-extensive with regions or portions thereof; domains may also include distinct, non-contiguous regions of a biomolecule. Examples of protein domains include, but are not IPTS / 128722251.1 Page 29 of 337Docket No.: AKT-031WO limited to, an Ig domain, an extracellular domain, a transmembrane domain, and a cytoplasmic domain.

[0172] As used herein, the term “engineered Kunitz domain” refers to a subgenus of miniproteins. An engineered Kunitz domain is preferably a peptide derived from the Kunitz 5 domain of a Kunitz-type protease inhibitor such as bovine pancreatic trypsin inhibitor (BPTI), amyloid precursor protein (APP) or tissue factor pathway inhibitor (TFPI). Kunitz domains have a molecular weight of approximately 6 kDa and domains with the required target specificity can be selected by display techniques such as phage display (Weidle et al., (2013), Cancer Genomics Proteomics; 10(4): 155-68). 0

[0173] As used herein, the term “expression control sequence” as used herein refers to polynucleotide sequences which are necessary to affect the expression of coding sequences to which they are operatively linked. Expression control sequences are sequences which control the transcription, post-transcriptional events and translation of nucleic acid sequences. Expression control sequences include appropriate transcription initiation, termination,5 promoter and enhancer sequences; efficient RNA processing signals such as splicing and polyadenylation signals; sequences that stabilize cytoplasmic mRNA; sequences that enhance translation efficiency (e.g., ribosome binding sites); sequences that enhance protein stability; and when desired, sequences that enhance protein secretion. The nature of such control sequences differs depending upon the host organism; in prokaryotes, such control sequences0 generally include promoter, ribosomal binding site, and transcription termination sequence. The term “control sequences” is intended to include, at a minimum, all components whose presence is essential for expression, and can also include additional components whose presence is advantageous, for example, leader sequences and fusion partner sequences.

[0174] As used herein, the term “functional variant” refers to a polypeptide that comprises5 or consists of a portion of a sequence of a polypeptide provided herein, and still retains one or more functions of a polypeptide comprising or consisting of an entire amino acid sequence as provided herein (e.g., still binds to a target, e.g., Nectin-4).

[0175] As used herein, the term “fusion protein” refers to a polypeptide comprising a polypeptide or fragment coupled to heterologous amino acid sequences. Fusion proteins are0 useful because they can be constructed to contain two or more desired functional elements from two or more different proteins. A fusion protein comprises at least 10 contiguous amino acids from a polypeptide of interest, more preferably at least 20 or 30 amino acids, even more preferably at least 40, 50 or 60 amino acids, yet more preferably at least 75, 100 or 125 amino acids. Fusions that include the entirety of the proteins of the present disclosure have IPTS / 128722251.1 Page 30 of 337Docket No.: AKT-031WO particular utility. The heterologous polypeptide included within the fusion protein of the present disclosure is at least 6 amino acids in length, often at least 8 amino acids in length, and usefully at least 15, 20, and 25 amino acids in length. Fusions that include larger polypeptides, such as an IgG Fc region, and even entire proteins, such as the green 5 fluorescent protein (“GFP”) chromophore-containing proteins, have particular utility. Fusion proteins can be produced recombinantly by constructing a nucleic acid sequence which encodes the polypeptide or a fragment thereof in frame with a nucleic acid sequence encoding a different protein or peptide and then expressing the fusion protein. Alternatively, a fusion protein can be produced chemically by crosslinking the polypeptide or a fragment0 thereof to another protein.

[0176] As used herein, when referring to a protein, “homology” to a second protein can exist if the nucleic acid sequence that encodes the protein has a similar sequence to the nucleic acid sequence that encodes the second protein. Alternatively, a protein has homology to a second protein if the two proteins have “similar” amino acid sequences. (Thus, the term5 “homologous proteins” is defined to mean that the two proteins have similar amino acid sequences.) Homology between two regions of amino acid sequences (especially with respect to predicted structural similarities) can be interpreted as implying similarity in function. Homologous proteins or peptides with residue positions that are not identical are often recognized to differ by conservative amino acid substitutions. 0

[0177] As used herein the term “identical” refers to a nucleic acid sequence or amino acid sequence of at least two nucleic acid or at least two amino acid sequences or subsequences that have a specified percentage of nucleotides or amino acids, respectively, that are the same, when compared and aligned for maximum correspondence, as measured using a sequence comparison algorithm or by visual inspection. For sequence comparison, typically5 one sequence acts as a reference sequence, to which test (i.e. query) sequences are compared. A length of sequence identity comparison may be over a stretch of any number of nucleotides or amino acids. When using a sequence comparison algorithm, test and reference sequences are input into a computer, subsequence coordinates are designated, if necessary, and sequence algorithm program parameters are designated. The sequence comparison algorithm0 then calculates the percent sequence identity for the test sequence(s) relative to the reference sequence, based on the designated program parameters. A number of algorithms are known in the art. Non-limiting examples of algorithms that are suitable for determining percent sequence identity and sequence similarity are the BLAST and BLAST 2.0 algorithms, which are described in, e.g., Altschul et al. (1990) J. Mol. Biol.215: 403-410 and Altschul et al. IPTS / 128722251.1 Page 31 of 337Docket No.: AKT-031WO (1977) Nucleic Acids Res.25: 3389-3402, respectively. Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information. Additionally, or alternatively, sequences can be compared using FASTA, Gap or Bestfit, which are programs in Wisconsin Package Version 10.0, Genetics Computer Group (GCG), 5 Madison, Wis. FASTA provides alignments and percent sequence identity of the regions of the best overlap between the query and search sequences. Pearson, Methods Enzymol. 183:63-98 (1990) (hereby incorporated by reference in its entirety). For instance, percent sequence identity can be determined using FASTA with its default parameters (a word size of 6 and the NOPAM factor for the scoring matrix) or using Gap with its default parameters as0 provided in GCG Version 6.1, herein incorporated by reference. Percent identity is not necessarily determined over the entire length of two sequences. That is, for example, with a reference sequence and a query sequence, one may be longer or shorter than the other and percent identity is determined based on match over the length of a particular stretch of nucleic acids or amino acids. For example, if a sequence disclosed herein is compared to a5 query sequence and the query is shorter, a percent identity is determined by aligning the reference and query and determining the percent identity as between the query and the portion of the reference sequence over which it aligns. If the query is longer than the disclosed sequence, percent identity is identity over an aligned portion with the reference sequence (e.g., over 5, 10, 15, 20, 25, 30, 35 or more amino acids of a miniprotein). 0

[0178] As used herein, the term “isolated” polynucleotide or polypeptide is one which is substantially separated from other cellular components that naturally accompany the native polynucleotide in its natural host cell, e.g., ribosomes, polymerases and genomic sequences with which it is naturally associated. For instance, an isolated molecule is one that by virtue of its origin or source of derivation (1) is not associated with naturally associated components5 that accompany it in its native state, (2) exists in a purity not found in nature, where purity can be adjudged with respect to the presence of other cellular material (e.g., is free of other proteins from the same species) (3) is expressed by a cell from a different species, or (4) does not occur in nature (e.g., it is a fragment of a polynucleotide or polypeptide found in nature or it includes amino acid analogs or derivatives not found in nature or linkages other than0 standard peptide bonds). Thus, a polynucleotide or polypeptide that is chemically synthesized or synthesized in a cellular system different from the cell from which it naturally originates will be “isolated” from its naturally associated components. A polynucleotide or polypeptide may also be rendered substantially free of naturally associated components by isolation, using protein purification techniques well known in the art. As thus defined, “isolated” does IPTS / 128722251.1 Page 32 of 337Docket No.: AKT-031WO not necessarily require that any molecule so described has been physically removed from its native environment. In some embodiments, as used in reference to an isolated construct, isolated means in the absence of a pharmaceutically acceptable salt.

[0179] As used herein, the term “Ki” (M) refers to the binding inhibition constant of a 5 given entity and a target (e.g., a particular polypeptide-target interaction).

[0180] As used herein, the term “kd” (s-1) refers to the dissociation rate constant between a given entity and a target (e.g., of a particular polypeptide-target interaction). This value is also referred to as the koffvalue.

[0181] As used herein, the term “ka” (M-1×s-1) refers to the association rate constant of a0 given entity and a target (e.g., a particular polypeptide-target interaction). This value is also referred to as the kon value.

[0182] As used herein, the term “KD” (M) refers to the dissociation equilibrium constant of a given entity and a target ( particular interaction between an entity and its target (e.g., a polypeptide-target interaction). KD = kd / ka. 5

[0183] As used herein, the term “KA” (M-1) refers to the association equilibrium constant of a given entity and a target (e.g., a particular polypeptide-target interaction). KA = ka / kd.

[0184] The affinity of a molecule X for its target Y can be represented by the dissociation equilibrium constant (KD). The kinetic components that contribute to the dissociation equilibrium constant are as described above. For clarity, as known in the art, a smaller KD0 value indicates a higher affinity interaction, while a larger KDvalue indicates a lower affinity interaction. Affinity can be measured by common methods known in the art, including those described herein, such as surface plasmon resonance (SPR) technology (e.g., BIACORE®) or biolayer interferometry (e.g., FORTEBIO®).

[0185] In some embodiments, the peptide or miniprotein (e.g., targeting miniprotein, e.g.,5 Nectin-4-binding miniprotein) of the present disclosure binds to Nectin-4 with a dissociation equilibrium constant (KD) of less than about 10-7M, such as less than about 10-8M, 10-9M, or 10-10M or less, for example, as determined using surface plasmon resonance (SPR) techniques in an SPR machine, such as a BIACORE T200 instrument.

[0186] As used herein, the term “knock out” generally refers to a gene whose level of0 expression or activity has been reduced to zero. In some examples, a gene is knocked out via deletion of some or all of its coding sequence. In other examples, a gene is knocked out via introduction of one or more nucleotides into its open reading frame, which results in translation of a nonsense or otherwise nonfunctional protein product. IPTS / 128722251.1 Page 33 of 337Docket No.: AKT-031WO

[0187] As used herein, the term “knottin” refers to a structural motif of a miniprotein containing three disulfide bridges.

[0188] As used herein, the term “knottin peptide” refers to a subgenus of miniproteins that comprises at least one knottin. 5

[0189] As used herein, the term “linker” refers to a moiety that is used to conjugate a miniprotein to a chelator.

[0190] As used herein, the term “miniprotein” refers to short proteins of less than or equal to about 100 amino acids with well-defined folds comprising two or more secondary structure elements, a sequestered hydrophobic core, and / or cooperative folding. CDPs,0 knottins, affibodies, engineered Kunitz domains, monobodies (adnectins), anticalins, designed ankyrin repeat domains (DARPins), and avimers, as disclosed herein are all examples of miniproteins. Further, a miniprotein can refer to a linear polypeptide, a folded polypeptide (e.g., covalently linked polypeptide, non-covalently linked polypeptide, or polypeptide include a di-sulfide linkage), cysteine-dense peptide, a knottin peptide, a binder,5 an affibody, an engineered Kunitz domain, a monobody, an anticalin, a designed ankyrin repeat domain (DARPin), or an avimer.

[0191] As used herein, the term “modification,” with reference to a nucleic acid sequence, refers to a nucleic acid sequence that comprises at least one substitution, alteration, inversion, addition, or deletion of nucleotide compared to a reference nucleic acid sequence. As used0 herein, the term “modification,” with reference to an amino acid sequence refers to an amino acid sequence that comprises at least one substitution, alteration, inversion, addition, or deletion of an amino acid residue compared to a reference amino acid sequence. An alteration can include but is not limited to a change to or of one or more atoms of a side chain, such as, for example addition of a methyl-group (e.g., methylated versions of lysine). 5 In some embodiments, a natural amino acid is modified such as set forth herein.

[0192] As used herein, the term “modified derivative” refers to polypeptides or fragments thereof that are substantially homologous in primary structural sequence, but which include e.g., in vivo or in vitro chemical and biochemical modifications or which incorporate amino acids that are not found in the native polypeptide. Such modifications include, for example,0 acetylation, carboxylation, phosphorylation, glycosylation, ubiquitination, labeling, e.g., with radionuclides, and various enzymatic modifications, as will be readily appreciated by those skilled in the art. A variety of methods for labeling polypeptides and of substituents or labels useful for such purposes are well known in the art, and include radioactive isotopes such as 125I, 32P, 35S, and 3H, ligands which bind to labeled antiligands (e.g., antibodies), IPTS / 128722251.1 Page 34 of 337Docket No.: AKT-031WO fluorophores, chemiluminescent agents, enzymes, and antiligands which can serve as specific binding pair members for a labeled ligand. The choice of label depends on the sensitivity required, ease of conjugation with the primer, stability requirements, and available instrumentation. Methods for labeling polypeptides are well known in the art. See, e.g., 5 Ausubel et al., Current Protocols in Molecular Biology, Greene Publishing Associates (1992, and Supplements to 2002).

[0193] As used herein, the term “molecule” means any compound, including, but not limited to, a miniprotein, a small molecule, peptide, protein, sugar, nucleotide, nucleic acid, lipid, etc., and such a molecule (e.g., miniprotein, compound, etc.) can be natural or synthetic0 or a combination of natural and synthetic.

[0194] As used herein, the term “monobody” or “adnectin” are used interchangeably and refer to a subgenus of miniproteins. A monobody relates to a molecule, preferably based on the 10th extracellular domain of human fibronectin III (10Fn3), which adopts an Ig-like b- sandwich fold of preferably 94 residues with 2 to 3 exposed loops but lacks the central5 disulfide bridge (Gebauer and Skerra (2009) Curr Opinion in Chemical Biology 13:245-255). Adnectins with the desired target specificity can be genetically engineered by introducing modifications in specific loops of the protein.

[0195] As used herein, the term “mutein” or “mutant protein” or “variant” means a protein comprising an amino acid sequence with at least one variation (e.g., an insertion, a0 deletion, or a substitution, which can be a conservative or non-conservative substitution) compared to a reference sequence. When applied to sequences (e.g., nucleic acid sequences, amino acid sequences) “mutated” means that nucleotides in a nucleic acid sequence or amino acids in an amino acid sequence may be inserted, deleted or changed compared to a reference sequence. A single alteration may be made at a locus (a point mutation) or multiple5 nucleotides or amino acids may be inserted, deleted or changed at a single locus. In addition, one or more alterations may be made at any number of loci within a nucleic acid or amino acid sequence. A nucleic acid or amino acid sequence may be mutated by any method known in the art including but not limited to mutagenesis techniques such as “error-prone PCR” (a process for performing PCR under conditions where the copying fidelity of the DNA0 polymerase is low, such that a high rate of point mutations is obtained along the entire length of the PCR product; see, e.g., Leung et al., Technique, 1:11-15 (1989) and Caldwell and Joyce, PCR Methods Applic.2:28-33 (1992)); “oligonucleotide-directed mutagenesis” (a process which enables the generation of site-specific mutations in any cloned DNA segment of interest; see, e.g., Reidhaar-Olson and Sauer, Science 241:53-57 (1988)); directed IPTS / 128722251.1 Page 35 of 337Docket No.: AKT-031WO evolution (e.g., exposing a polypeptide to differing sets of conditions resulting in production of different polypeptides with one or more amino acid changes that may or may not confer greater fitness upon the polypeptide); and site-directed mutagenesis (e.g., specifically directed changes in a sequence). 5

[0196] As used herein, the terms “polypeptide mutant” or “mutein” refer to a polypeptide whose sequence contains an insertion, duplication, deletion, rearrangement, or substitution of one or more amino acids compared to the amino acid sequence of a native or wild-type protein. A mutein may have one or more amino acid point substitutions, in which a single amino acid at a position has been changed to another amino acid, one or more insertions0 and / or deletions, in which one or more amino acids are inserted or deleted, respectively, in the sequence of the naturally-occurring protein, and / or truncations of the amino acid sequence at either or both the amino or carboxy termini. A mutein may have the same but preferably has a different biological activity compared to the naturally-occurring protein. A mutein has at least 85% overall sequence homology to its wild-type counterpart. Even more5 preferred are muteins having at least 90% overall sequence homology to the wild-type protein. In an even more preferred embodiment, a mutein exhibits at least 95% sequence identity, even more preferably 98%, even more preferably 99% and even more preferably 99.9% overall sequence identity. Sequence homology may be measured by any common sequence analysis algorithm, such as Gap or Bestfit. Amino acid substitutions can include0 those which: (1) reduce susceptibility to proteolysis, (2) reduce susceptibility to oxidation, (3) alter binding affinity for forming protein complexes, (4) alter binding affinity or enzymatic activity, and (5) confer or modify other physicochemical or functional properties of such analogs.

[0197] As used herein, the term “non-disulfide sequence” refers to an amino acid5 sequence encoding a polypeptide that does not comprise more than one cysteine residue and / or disulfide bonds in its folded and active form. For example, in some embodiments, a miniprotein may comprise or consist of a non-disulfide sequence.

[0198] As used herein, the term “non-peptide analog” refers to a compound with properties that are analogous to those of a reference polypeptide. A non-peptide compound0 may also be termed a “peptide mimetic” or a “peptidomimetic.” See, e.g., Jones, Amino Acid and Peptide Synthesis, Oxford University Press (1992); Jung, Combinatorial Peptide and Nonpeptide Libraries: A Handbook, John Wiley (1997); Bodanszky et al., Peptide Chemistry--A Practical Textbook, Springer Verlag (1993); Synthetic Peptides: A Users Guide, (Grant, ed., W. H. Freeman and Co., 1992); Evans et al., J. Med. Chem.30:1229 IPTS / 128722251.1 Page 36 of 337Docket No.: AKT-031WO (1987); Fauchere, J. Adv. Drug Res.15:29 (1986); Veber and Freidinger, Trends Neurosci., 8:392-396 (1985); and references sited in each of the above, which are incorporated herein by reference. Such compounds are often developed with the aid of computerized molecular modeling. Peptide mimetics that are structurally similar to useful peptides of the present 5 disclosure may be used to produce an equivalent effect and are therefore envisioned to be part of the present disclosure.

[0199] As used herein, the terms “nucleic acid sequence” and “polynucleotide” are used interchangeably to refer to a polymer of nucleotides. The term includes DNA molecules (e.g., cDNA or genomic or synthetic DNA) and RNA molecules (e.g., mRNA or synthetic RNA),0 as well as analogs of DNA or RNA containing non-natural nucleotide analogs, non-native internucleoside bonds, or both. The nucleic acid can be in any topological conformation. For instance, the nucleic acid can be single-stranded, double-stranded, triple-stranded, quadruplexed, partially double-stranded, branched, hairpinned, circular, or in a padlocked conformation. The nucleic acid sequence can contain natural, non-natural, or altered 5 nucleotides; and contain a natural, non-natural, or altered internucleotide linkage, such as a phosphoramidate linkage or a phosphorothioate linkage, instead of the phosphodiester found between the nucleotides of an unmodified nucleic acid sequence. Nucleic acid sequences include, but are not limited to, all nucleic acid sequences which are obtained by any means available in the art, including, without limitation, recombinant means, e.g., the cloning of0 nucleic acid sequences from a recombinant library or a cell genome, using ordinary cloning technology and polymerase chain reaction, and the like, and by synthetic means. Polynucleotides of the present disclosure may include both sense and antisense strands of RNA, cDNA, genomic DNA, and synthetic forms and mixed polymers of the above. They may be modified chemically or biochemically or may contain non-natural or derivatized5 nucleotide bases, as will be readily appreciated by those of skill in the art. Such modifications include, for example, labels, methylation, substitution of one or more of the naturally occurring nucleotides with an analog, internucleotide modifications such as uncharged linkages (e.g., methyl phosphonates, phosphotriesters, phosphoramidates, carbamates, etc.), charged linkages (e.g., phosphorothioates, phosphorodithioates, etc.),0 pendent moieties (e.g., polypeptides), intercalators (e.g., acridine, psoralen, etc.), chelators, alkylators, and modified linkages (e.g., alpha anomeric nucleic acids, etc.) Also included are synthetic molecules that mimic polynucleotides in their ability to bind to a designated sequence via hydrogen bonding and other chemical interactions. Such molecules are known in the art and include, for example, those in which peptide linkages substitute for phosphate IPTS / 128722251.1 Page 37 of 337Docket No.: AKT-031WO linkages in the backbone of the molecule. Other modifications can include, for example, analogs in which the ribose ring contains a bridging moiety or other structure such as the modifications found in “locked” nucleic acids.

[0200] As used herein, the terms “operatively linked” or “operably linked” expression 5 control sequences refer to a linkage in which the expression control sequence is contiguous with the gene of interest to control the gene of interest, as well as expression control sequences that act in trans or at a distance to control the gene of interest.

[0201] As used herein, the term “polypeptide fragment” as used herein refers to a polypeptide that has a deletion, e.g., an amino-terminal and / or carboxy-terminal deletion0 compared to a full-length polypeptide. In a preferred embodiment, the polypeptide fragment is a contiguous sequence in which the amino acid sequence of the fragment is identical to the corresponding positions in the naturally-occurring sequence. Fragments typically are at least 5, 6, 7, 8, 9 or 10 amino acids long, preferably at least 12, 14, 16 or 18 amino acids long, more preferably at least 20 amino acids long, more preferably at least 25, 30, 35, 40 or 45,5 amino acids, even more preferably at least 50 or 60 amino acids long, and even more preferably at least 70 amino acids long.

[0202] As used herein, the term “radionuclide” refers to an atom capable of undergoing radioactive decay.

[0203] As used herein, the term “radiotherapeutic” refers to a radionuclide-labeled0 miniprotein or compound as provided herein, comprising a radionuclide. A radiotherapeutic may be administered to a subject, such as a test subject (e.g., a mouse or rat, e.g., a non- human primate, e.g., a healthy volunteer), and / or a subject in need of radiotherapy, e.g., a subject with a cancer.

[0204] As used herein, the term “recombinant” refers to a biomolecule, e.g., a gene or5 protein, that (1) has been removed from its naturally occurring environment, (2) is not associated with all or a portion of a polynucleotide in which the gene is found in nature, (3) is operatively linked to a polynucleotide which it is not linked to in nature, and / or (4) does not occur in nature. The term “recombinant” can be used in reference to cloned DNA isolates, chemically synthesized polynucleotide analogs, or polynucleotide analogs that are 0 biologically synthesized by heterologous systems, as well as proteins and / or mRNAs encoded by such nucleic acids. As used herein, an endogenous nucleic acid sequence in the genome of an organism (or the encoded protein product of that sequence) is deemed “recombinant” herein if a heterologous sequence is placed adjacent to the endogenous nucleic acid sequence, such that the expression of this endogenous nucleic acid sequence is IPTS / 128722251.1 Page 38 of 337Docket No.: AKT-031WO altered. In this context, a heterologous sequence is a sequence that is not naturally adjacent to the endogenous nucleic acid sequence, whether or not the heterologous sequence is itself endogenous (originating from the same host cell or progeny thereof) or exogenous (originating from a different host cell or progeny thereof). By way of example, a promoter 5 sequence can be substituted (e.g., by homologous recombination) for the native promoter of a gene in the genome of a host cell, such that this gene has an altered expression pattern. This gene would now become “recombinant” because it is separated from at least some of the sequences that naturally flank it. A nucleic acid is also considered “recombinant” if it contains any modifications that do not naturally occur to the corresponding nucleic acid in a0 genome. For instance, an endogenous coding sequence is considered “recombinant” if it contains an insertion, deletion or a point mutation introduced artificially, e.g., by human intervention. A “recombinant nucleic acid” also includes a nucleic acid integrated into a host cell chromosome at a heterologous site and a nucleic acid construct present as an episome.

[0205] As used herein, the term “recombinant host cell” (or simply “host cell”), as used5 herein, is intended to refer to a cell into which a recombinant vector has been introduced. It should be understood that such terms are intended to refer not only to the particular subject cell but to the progeny of such a cell. Because certain modifications may occur in succeeding generations due to either mutation or environmental influences, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term “host0 cell” as used herein. A recombinant host cell may be an isolated cell or cell line grown in culture or may be a cell which resides in a living tissue or organism.

[0206] As used herein, the term “region” as used herein refers to a physically contiguous portion of the primary structure of a biomolecule. In the case of proteins, a region is defined by a contiguous portion of the amino acid sequence of that protein. 5

[0207] As used herein the phrase “secondary structure elements” refers to local folded structures that form within a polypeptide due to interactions between atoms of its backbone. Examples of secondary structure elements can include an alpha helix, a beta sheet, a 310 helix, a pi helix, and a random coil. A miniprotein of the present disclosure may comprise one or more of any of such secondary structures (e.g., one or more alpha helix, one or more0 alpha helices and one or more beta sheets). It will be understood by those of skill in the art that secondary structure elements may be joined by loop regions, which may or may not be modified to change the interactions of secondary structure elements of the polypeptide. As will be understood to those of skill in the art, in some embodiments, loops may be secondary IPTS / 128722251.1 Page 39 of 337Docket No.: AKT-031WO structural elements. In some embodiments, loops may be interstructural elements that are not necessarily considered secondary structural elements.

[0208] As used herein, “sequence homology” for polypeptides, also referred to as “percent sequence identity,” is typically measured using sequence analysis software. See, 5 e.g., the Sequence Analysis Software Package of the Genetics Computer Group (GCG), University of Wisconsin Biotechnology Center, 910 University Avenue, Madison, Wis. 53705. Protein analysis software matches similar sequences using a measure of homology assigned to various substitutions, deletions and other modifications, including conservative amino acid substitutions. For instance, GCG contains programs such as “Gap” and “Bestfit”0 which can be used with default parameters to determine sequence homology or sequence identity between closely related polypeptides, such as homologous polypeptides from different species of organisms or between a wild-type protein and a mutein thereof. See, e.g., GCG Version 6.1. A preferred algorithm when comparing a particular polypeptide sequence to a database containing a large number of sequences from different organisms is the5 computer program BLAST (Altschul et al., J. Mol. Biol.215:403-410 (1990); Gish and States, Nature Genet.3:266-272 (1993); Madden et al., Meth. Enzymol.266:131-141 (1996); Altschul et al., Nucleic Acids Res.25:3389-3402 (1997); Zhang and Madden, Genome Res. 7:649-656 (1997)), especially blastp or tblastn (Altschul et al., Nucleic Acids Res.25:3389- 3402 (1997)). Preferred parameters for BLASTp are: Expectation value: 10 (default); Filter:0 seg (default); Cost to open a gap: 11 (default); Cost to extend a gap: 1 (default); Max. alignments: 100 (default); Word size: 11 (default); No. of descriptions: 100 (default); Penalty Matrix: BLOSUM62. The length of polypeptide sequences compared for homology will generally be at least about 16 amino acid residues, usually at least about 20 residues, more usually at least about 24 residues, typically at least about 28 residues, and preferably more5 than about 35 residues. When searching a database containing sequences from a large number of different organisms, it is preferable to compare amino acid sequences. Database searching using amino acid sequences can be measured by algorithms other than blastp known in the art. For instance, polypeptide sequences can be compared using FASTA, a program in GCG Version 6.1. FASTA provides alignments and percent sequence identity of0 the regions of the best overlap between the query and search sequences. Pearson, Methods Enzymol.183:63-98 (1990) (incorporated by reference herein). For example, percent sequence identity between amino acid sequences can be determined using FASTA with its default parameters (a word size of 2 and the PAM250 scoring matrix), as provided in GCG Version 6.1, herein incorporated by reference. IPTS / 128722251.1 Page 40 of 337Docket No.: AKT-031WO

[0209] As used herein, the term “specific activity” generally refers to the activity per unit mass of a radionuclide. The unity of specific activity may include units of becquerel per kilogram (Bq / kg) or curie per gram (Ci / g).

[0210] As used herein, the term “specificity” generally refers to a sequence (e.g., of a 5 protein, e.g. of a miniprotein, e.g. a miniprotein having certain amino acids) that, when in a conformation that can bind, selectively or “specifically” binds to a specific target (e.g. an antigen, such as expressed on a tumor, e.g., Nectin-4, e.g., certain cell types, e.g., kidney cells, e.g., kidney proximal tubule cells, etc.).

[0211] As used herein, “specifically binds” means that the binding of a polynucleotide,0 polypeptide, or protein is selective for a specified antigen (e.g., target) and can be discriminated from unwanted or non-specific interactions. For example, the ability of a protein (e.g., cysteine-dense peptides) to bind to a specific antigenic determinant can be measured techniques familiar to one of skill in the art, for example through an enzyme-linked immunosorbent assay (ELISA) or surface plasmon resonance. Between two molecules (e.g.,5 entities such as miniproteins), “specific binding” refers to the ability of two molecules to bind to each other in preference to binding to other molecules in the environment. Typically, “specific binding” discriminates over adventitious binding in a reaction by at least two-fold, more typically by at least 10-fold, often at least 100-fold, or even 1,000-fold. Typically, the affinity or avidity of a specific binding reaction, as quantified by a dissociation constant, is0 about 10-7M or stronger (e.g., about 10-8M, 10-9M or even stronger). Specific-binding requires specificity of a particular first entity (e.g., a polypeptide) for a particular second entity (e.g., an antigen binding sequence).

[0212] As used herein, the term “stabilizer” in the context of a pharmaceutical composition refers to an agent, molecule, or compound that may act to impact the active pharmaceutical5 ingredient or ingredients to maintain desirable properties (e.g., therapeutic properties or properties that allow therapeutic effect to be achieved) until it is administered to a subject.

[0213] As used herein “stringent hybridization conditions” and “stringent wash conditions” in the context of nucleic acid hybridization experiments depend upon a number of different physical parameters. Nucleic acid hybridization will be affected by such0 conditions as salt concentration, temperature, solvents, the base composition of the hybridizing species, length of the complementary regions, and the number of nucleotide base mismatches between the hybridizing nucleic acids, as will be readily appreciated by those skilled in the art. One having ordinary skill in the art knows how to vary these parameters to achieve a particular stringency of hybridization. In general, “stringent hybridization” is IPTS / 128722251.1 Page 41 of 337Docket No.: AKT-031WO performed at about 25°C below the thermal melting It (Tm) for the specific DNA hybrid under a particular set of conditions. “Stringent washing” is performed at temperatures about 5°C lower than the Tm for the specific DNA hybrid under a particular set of conditions. The Tm is the temperature at which 50% of the target sequence hybridizes to a perfectly matched 5 probe. See Sambrook et al., Molecular Cloning: A Laboratory Manual, 2d ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989), page 9.51, hereby incorporated by reference. For purposes herein, “stringent conditions” are defined for solution phase hybridization as aqueous hybridization (i.e., free of formamide) in 6xSSC (where 20xSSC contains 3.0 M NaCl and 0.3 M sodium citrate), 1% SDS at 65°C for 8-12 h, followed by two0 washes in 0.2xSSC, 0.1% SDS at 65ºC for 20 minutes. It will be appreciated by the skilled worker that hybridization at 65°C will occur at different rates depending on a number of factors including the length and percent identity of the sequences which are hybridizing.

[0214] As used herein, the term “synthetic” is used to refer to an entity that is made is lab- created and not naturally produced or isolated, without modification, from a naturally5 occurring source. A recombinant polymer, such as a recombinant polynucleotide or polypeptide, may be synthetic. Synthetic polymers such as polynucleotides or polypeptides may be produced by any method known to those of skill in the art, including but not limited to solid phase synthesis, solution phase synthesis, biological synthesis by, e.g., host cells, etc.

[0215] As used herein, the term “subject” is a mammal. A subject may be a human or non-0 human mammal. Given context, a subject may be used interchangeably with patient, individual, donor, etc. In some embodiments, a subject is a healthy subject without a disease that is contemplated for treatment by a composition of the disclosure (e.g., a healthy volunteer being administered one or more compositions provided herein). In some embodiments, a subject is one suspected or diagnosed as having a disease, disorder, or5 condition, such as a cancer and / or tumor, as provided herein. In some such embodiments, such a subject is considered for treatment by a composition of the disclosure. In some embodiments, analyses of results achieved with technologies disclosed herein are evaluated in a population comprising a plurality of subjects.

[0216] As used herein, the terms “substantial homology” or “substantial similarity,”0 when referring to a polynucleotide or polypeptide, indicate that, when optimally aligned with appropriate nucleotide or amino acid insertions or deletions with another reference molecule (or its complementary strand when appropriate), there is sequence identity in at least about 70%, 75%, 80%, 85%, preferably at least about 90%, and more preferably at least about 95%, 96%, 97%, 98% or 99% or more of the nucleic acid or amino acid residues, as IPTS / 128722251.1 Page 42 of 337Docket No.: AKT-031WO measured by any well-known algorithm of sequence identity, such as, e.g., FASTA, BLAST, Gap, etc.. Alternatively or additionally, substantial homology or similarity exists when, for example, a nucleic acid or fragment thereof hybridizes to another nucleic acid, to a strand of another nucleic acid, or to the complementary strand thereof, under stringent hybridization 5 conditions.

[0217] As used herein, the term “target” refers to a protein or functional portion or variant thereof. A target is a protein to which another protein (e.g. a miniprotein) is designed to bind. A target may be or comprise a binding region, such as an epitope, to which a miniprotein (e.g., CDP, knottin, binder, affibody, engineered Kunitz domain, monobody, anticalin,0 designed ankyrin repeat domain (DARPin), avimer) of the present disclosure binds. Further, the term “antigen” refers to a protein or functional portion or variant thereof to which a polypeptide (e.g., a miniprotein, etc.) or variant thereof binds to. A target may be or comprise an antigen. A target may be expressed on the surface of a particular cell (a “target cell”) or expressed within (e.g., on the surfaces of) cells in a population of cells. A target may have a5 certain percent identity to a reference protein and still be referred to as a target by a particular name (e.g., Nectin-4). In certain embodiments that will be clear from context, a target may also refer to a protein in a pathway related to another protein. For example, if a target is Nectin-4, a target may also be a protein in a pathway that is necessary for Nectin-4 activity. A target may be or comprise a binding region, such as an epitope, to which a miniprotein of0 the present disclosure binds. In certain embodiments that will be clear given context, a target may also be a particular cell type (or be localized to a particular cell type) characterized by expression of particular surface entities such as receptors (e.g., a cell in a tissue, e.g., a proximal tubule cell in a kidney). Such targets may be different or the same as a target to which a miniprotein (M) is designed to bind; in some embodiments, a target (e.g., a non-5 tumor cell, e.g., a kidney cell, etc.) is bound by a decoy rather than a polypeptide (e.g., a miniprotein) of a composition (e.g., a radiotherapeutic composition) provided herein.

[0218] As used herein “thermal stability” refers to the ability of a miniprotein to remain stable (e.g., not unfolded, e.g., structurally intact) over a period of time. In some embodiments, a miniprotein of the present disclosure retains at least 95% of its stability for at0 least one hour.

[0219] As used herein, a treatment that is “tolerable” to a subject refers to a therapeutic administration and / or regimen that is not terminated because of dose-limiting toxicity.

[0220] As used herein, the term “treatment” (as well as “treat” or “treating”) refers to partial or complete alleviation, amelioration, mitigation, prevention, reduction in risk of IPTS / 128722251.1 Page 43 of 337Docket No.: AKT-031WO onset, relief, inhibition, delay in onset of, reduction in severity of, reduction in frequency or incidence of one or more causes, features, and / or symptoms of or associated with a particular disease, disorder, and / or condition.

[0221] As used herein, the term “vector” is intended to refer to a nucleic acid molecule 5 capable of transporting another nucleic acid to which it has been linked. One type of vector is a “plasmid,” which generally refers to a circular double stranded DNA loop into which additional DNA segments may be ligated, but also includes linear double-stranded molecules such as those resulting from amplification by the polymerase chain reaction (PCR) or from treatment of a circular plasmid with a restriction enzyme. Other vectors include cosmids,0 bacterial artificial chromosomes (BAC) and yeast artificial chromosomes (YAC). Another type of vector is a viral vector, wherein additional DNA segments may be ligated into the viral genome (discussed in more detail below). Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., vectors having an origin of replication which functions in the host cell). Other vectors can be integrated into the genome5 of a host cell upon introduction into the host cell and are thereby replicated along with the host genome. Moreover, certain preferred vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as “recombinant expression vectors” (or simply “expression vectors”).

[0222] As used herein, the term “decoy peptides” or “decoys” refers to a subgenus of0 miniproteins specifically designed to (i) decrease accumulation of a compound (e.g., a miniprotein, e.g., a radiolabeled miniprotein, e.g., a radiotherapeutic as provided herein) in a non-tumor tissue (e.g., kidney tissue when the tumor is elsewhere); and / or (ii) have substantially no impact to minimal impact on compound uptake by a tumor (e.g., a tumor expressing a target, e.g., Nectin-4); and / or (iii) decrease adverse (e.g., toxic) accumulation in5 a non-tumor containing organ (e.g., kidney, etc.) of a subject. To give but one example, an exemplary decoy may be combined with a composition of the disclosure (e.g., comprising a miniprotein and a radionuclide) to block uptake and / or retention of the radioactive composition in kidney tissue, as compared to uptake and / or retention in kidney tissue in the absence of the decoy. Certain decoys are provided herein, such as C295-C297 (SEQ ID NOs:0 209-211). Decoys of the disclosure may bind to a target protein (e.g., Nectin-4) with an affinity of about 10-6M, 10-5M, 10-4M, 10-3M, or greater (e.g., 10-2M, etc.), or may have binding that is not detectable using measures including those provided herein. Without wishing to be bound by theory, the disclosure describes, in some embodiments, a decoy peptide (or decoy) that decoys a composition such as a radiotherapeutic, which means that IPTS / 128722251.1 Page 44 of 337Docket No.: AKT-031WO presence of the decoy in a non-tumor tissue (e.g., kidney) blocks uptake and / or retention of the radiotherapeutic into the non-tumor tissue (e.g., kidney). For clarity, when a decoy peptide is referred to as “decoying,” e.g., a composition, e.g., a compound, e.g., a miniprotein that binds to a target (e.g., Nectin-4), the decoy is not acting on the composition (or 5 compound or miniprotein), rather, it is acting on its own and, for example, even in the absence of a composition that it is decoying, if administered alone, would still be present in the non-tumor tissue (e.g., kidney).

[0223] As used herein, the term “scaffold” is used to describe miniproteins that share a general set of structural characteristics (e.g., certain constraints, secondary structures, tertiary0 structures, etc.). Any individual scaffold may include varying amounts of alpha helix, turn, and / or beta sheet, e.g. all alpha helix proteins (“a”), all beta sheet proteins (“b”), blended alpha helix / beta sheet proteins (“a / b”), blended alpha and beta proteins (“a+b”), and small proteins. Examples and features of certain scaffolds are provided herein, for example, as in compounds of TABLE 2A, e.g., C1-C293, e.g., C294. 5 Compositions

[0224] Provided herein are compositions comprising one or more of a polypeptide (e.g., miniprotein), linker, chelator, and / or radionuclide. In some embodiments, a composition comprises a linker and a chelator. In some such embodiments, the composition is metalated (e.g., with a cold-metal form of an elemental label, such as provided herein). In some0 embodiments, the composition is radiolabeled (e.g., with a radionuclide such as provided herein). In some embodiments, a composition comprises a linker, chelator, and radionuclide. In some embodiments, a composition comprises or consists of a polypeptide (i.e., miniprotein), an optional linker, and a chelator and / or radionuclide. In some embodiments, a chelator and / or radionuclide are conjugated to a miniprotein via a linker. In some 5 embodiments, a miniprotein of the present disclosure comprises or consists of a linear polypeptide, a folded polypeptide (e.g., covalently linked polypeptide, non-covalently linked polypeptide, or polypeptide include a di-sulfide linkage), cysteine-dense peptide, a knottin peptide, a binder, an affibody, an engineered Kunitz domain, a monobody, an anticalin, a designed ankyrin repeat domain (DARPin), or an avimer. In some embodiments, a 0 radionuclide of the present disclosure is an alpha emitter. In some such embodiments, a chelator and / or radionuclide are conjugated to a miniprotein via a linker.

[0225] Without wishing to be bound by any particular theory, the present disclosure contemplates that compositions of the present disclosure are more effective than previously described compositions (e.g., such as those comprising antibodies and / or beta-emitter IPTS / 128722251.1 Page 45 of 337Docket No.: AKT-031WO radionuclides). Such miniproteins or compositions comprising miniproteins can be used to treat subjects in need thereof with improved target specificity, increased speed of clearance, and decreased off-target effects (e.g., as compared to conjugates with non-alpha emitter radionuclides, e.g., as compared to compositions comprising antibodies or antibody-drug- 5 conjugates, etc.) For example, while miniproteins (e.g., to be used in compositions as provided herein) have several key features of antibody-based therapeutics (e.g., affinity, potency, specificity, and ability to disrupt protein:protein interactions), they can avoid undesirable limitations such as, e.g., large size, expensive manufacturing, and the necessity of chimerization or humanization. For instance, in some embodiments, a miniprotein (e.g., a0 linear polypeptide, a folded polypeptide (e.g., covalently linked polypeptide, non-covalently linked polypeptide, or polypeptide include a di-sulfide linkage), cysteine-dense peptide, a knottin peptide, a binder, an affibody, an engineered Kunitz domain, a monobody, an anticalin, a designed ankyrin repeat domain (DARPin), or an avimer) of the present disclosure is no more than about 100 amino acids in length. In some embodiments, such a5 miniprotein may be or comprise a cysteine dense peptide. In some embodiments, a miniprotein comprises one or more disulfide bridges. In some embodiments, a miniprotein comprises at least two disulfide bridges. In some embodiments, a miniprotein comprises no more than two disulfide bridges. In some embodiments, a miniprotein comprises multiple cysteine residues that crosslink to maintain a very stable, folded state for a peptide of its0 length (e.g., relative to a peptide of the same length without as many cysteine residues). Without wishing to be bound by theory, the disclosure contemplates that in some embodiments, a miniprotein does not comprise multiple cysteine residues such as, for example, a miniprotein comprising a single cysteine residue. In some such embodiments, the miniprotein may form a dimer, such as with another miniprotein (e.g., self-dimerization). In5 some embodiments, two miniproteins are linked together to form a dimer. In other embodiments, two miniproteins are each linked to a linker to form a dimer. In other embodiments, two different miniproteins are each linked to a linker to form a dimer. The present disclosure contemplates that stability conferred by crosslinked cysteines contributes to reduced immunogenicity of miniproteins or comprising such miniproteins. In some0 embodiments, such stability may also confer resistance to harsher conditions provided for efficient chelation (e.g., high temperature, low pH incubations, etc.), while continuing to retain biological activity (e.g., capability of binding a target).

[0226] In some embodiments, miniproteins as provided herein function as targeting moieties, e.g., specifically binding to a target expressed on the surface of a tumor cell. In IPTS / 128722251.1 Page 46 of 337Docket No.: AKT-031WO some such embodiments, a miniprotein is designed such that it may be joined to one or more additional components. For example, without being bound by any particular theory, miniproteins of the present disclosure may be formulated such that they are combined with other components such as a therapeutic molecule (e.g., chelator compositions and / or 5 radionuclide) and / or a detectable agent (e.g., a visualizable agent, e.g., a metabolizable and visualizable agent). In some such embodiments, such miniproteins conjugated to one or more additional components may be used, for example, in diagnosis, prognosis, monitoring, and / or treatment of one or more diseases, disorders or conditions such as those with expression of particular targets on particular populations of cells. 0

[0227] In some embodiments a miniprotein (e.g., a linear polypeptide, a folded polypeptide (e.g., covalently linked polypeptide, non-covalently linked polypeptide, or polypeptide include a di-sulfide linkage), cysteine-dense peptide, a knottin peptide, a binder, an affibody, an engineered Kunitz domain, a monobody, an anticalin, a designed ankyrin repeat domain (DARPin), or an avimer) has low immunogenicity relative to a larger protein. 5 In some such embodiments, the lower immunogenicity increases amenability to harsher environmental conditions (e.g., high temperature and low pH incubations) while retaining biological activity. Thus, in some embodiments, a conjugate comprising a miniprotein has lower immunogenicity than a composition comprising a larger protein or different targeting moiety (i.e., other than a miniprotein). 0

[0228] In some embodiments, a composition comprising a linker, chelator, and / or radionuclide can efficiently penetrate a tumor.

[0229] In some embodiments, miniproteins) have superior penetration efficiency relative to larger proteins. That is, in some embodiments, a miniprotein or composition comprising a miniprotein can penetrate a solid tumor better than a larger protein or composition 5 comprising a protein larger than a miniprotein. For example, in some embodiments, a binder has superior tumor penetration efficiency with a hydrodynamic radius on the order of about 1 nm – 25 nm. In some embodiments, the hydrodynamic radius is between about 1 nm -5 nm. In some embodiments, the hydrodynamic radius is between about 1 nm – 3 nm. In some embodiments, the hydrodynamic radius is about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,0 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 nm.

[0230] As described herein, miniproteins are conjugated to a chelator. In some embodiments, the chelator binds a radionuclide (e.g., an alpha-emitter radionuclide, e.g., actinium). In some such embodiments, such radionuclide conjugates combine specific- binding capabilities and properties of a miniprotein with a radionuclide. That is, without IPTS / 128722251.1 Page 47 of 337Docket No.: AKT-031WO being bound by any particular theory, the present disclosure provides a conjugate wherein, in some embodiments, a miniprotein targets a radioisotope to which it’s conjugated to a cell expressing a target. In some embodiments, the target is expressed on the surface of a cell. In some embodiments, the target is Nectin-4. In some embodiments, the cell is a tumor cell. In 5 some embodiments, the conjugate binds to the Nectin-4 on the surface of the tumor cell. In some such embodiments, the radionuclide is targeted to the tumor cell. In some embodiments, the radionuclide is an alpha-emitter radionuclide and when internalized, serves to specifically target (e.g., without damaging surrounding tissue / cells) the tumor cell. Targets 0

[0231] Any cell expressing a target may be targeted by a miniprotein as provided herein.

[0232] In some embodiments, a cell is a mammalian cell. In some embodiments, a cell is a human cell. In some embodiments, a cell is from a cell line. In some embodiments, a cell is a primary cell. In some embodiments, a primary cell is from a sample from a subject such as from a tumor or from corresponding tissue without a tumor (e.g., from another area of an5 organ or from a healthy donor). In some embodiments, a cell is in vitro (e.g., a primary cell, a cell line, etc.). In some embodiments, a cell is in vivo (e.g., in a subject, e.g., in a human subject, e.g., in a tumor of a human subject.) In some embodiments, a cell expresses or has been induced to express (e.g., via recombinant technology) a target. In some embodiments, the target is expressed on the surface of a cell. In some embodiments, a cell is contacted by a0 composition binding to a target expressed on its surface. In some embodiments, upon binding (e.g., upon binding of a miniprotein provided by the present disclosure), a target and any bound proteins and / or payloads is / are internalized into the cell. In some embodiments, a cell is killed by a payload (e.g., a radionuclide and / or chelator, etc.) after internalization.

[0233] In some embodiments, a target is a protein or portion thereof that is upregulated or5 overexpressed on cancer cells as compared to non-cancer cells. That is, in some embodiments, a target is expressed or overexpressed in a tumor or in a tumor microenvironment relative to a level of the target in non-diseased tissue (e.g., tissue without a tumor or tumor microenvironment). In some such embodiments, the target is absent or non- detectable in non-diseased (e.g., healthy) tissue. In some embodiments, a target is a 0 biomarker for cancer (e.g., for cancer cells, for a tumor).

[0234] In some embodiments, a target may be related to a protein such as, for example, a protein in a pathway activated or acted upon by another protein. For instance, in some embodiments, a protein may be expressed on the surface of a cancer cell and a target may be IPTS / 128722251.1 Page 48 of 337Docket No.: AKT-031WO a pathway that the surface-cell protein acts upon. In some embodiments, a protein may be expressed on a cancer cell and a target may be a protein on a different cell that causing a cancer cell to proliferate or otherwise be refractory to a treatment. In some embodiments, a tumor-associated cell surface molecule or tumor-specific cell surface molecule may be 5 targeted by a miniprotein or composition comprising a miniprotein as provided herein.

[0235] In some embodiments, the miniprotein or composition comprising a miniprotein specifically binds a target expressed on the surface of a cell. In some embodiments, a target is cleaved from a cell surface. In some such embodiments, if the target is in an organism, cleavage of the target results in circulation of the target throughout the system of the0 organism. In some such embodiments, a target is found at a particular level in, e.g., blood, serum, plasma. In some embodiments, however, a substantial portion of expressed target is localized to cell surfaces; thus, in some embodiments, measurements of a level of a target may not accurately reflect the amount of target in a population of cells (e.g., a tumor). In some embodiments, a target is a secreted protein. In some such embodiments, a target is5 found at a particular level in, e.g., blood, serum, plasma. In some such embodiments, the miniprotein binds to a region of a target such as, for example, an epitope. In some embodiments, a miniprotein or composition comprising a miniprotein specifically binds a target expressed on the surface of a cancer cell. In some embodiments, the cancer cell is in, on, or near a solid tumor. In some embodiments, the cancer cell is a circulating cancer cell. In0 some embodiments, a miniprotein or composition comprising a miniprotein specifically binds a target or expressed at a higher level on a cancer cell than a reference cell. In some embodiments, the cell is a mammalian cell. In some embodiments, the cell is a human cell.

[0236] In some embodiments, the miniprotein or composition comprising a miniprotein specifically binds to Nectin-4. In some embodiments, the target comprises or consists of5 Nectin-4. In some embodiments, the miniprotein specifically binds to a target comprising an amino acid sequence or portion thereof as set forth in TABLE 1A.

[0237] In some embodiments, the disclosure provides a composition, comprising a polypeptide of at least 44 amino acids in length and having an amino sequence comprising that set forth in SEQ ID NO: 171, wherein X2 is E or D; X6 is E or Q; X17 is G or A; X21 is0 Q, Y, or E; X26 is Kme3, Kme2, Kme, K, Kipr, or S; X32 is A, G, or D; X41 is N or K; and X45 is S or absent.

[0238] In certain embodiments, the disclosure provides a composition, comprising a polypeptide of at least 44 amino acids in length and having an amino acid sequence comprising that set forth in SEQ ID NO: 176, wherein X2 is E or D; X6 is E or Q; X9 is T or IPTS / 128722251.1 Page 49 of 337Docket No.: AKT-031WO A; X10 is A or G; X12 is A, Kme3, Kme2, Kme, Kipr or K; X13 is R or (Cit) X17 is G or A; X21 is Q, Y, or E; X24 is Q or K; X25 is A or K; X26 is Kme3, Kme2, Kme, K, Kipr, or S; X28 is Q or K; X29 is Y or K; X30 is L or V; X32 is A, G, or D; X41 is N or K; and X45 is S or absent. 5

[0239] In some embodiments, the disclosure provides a composition, comprising a Nectin-4 binding polypeptide having an amino acid sequence comprising at least 44 amino acids, wherein the amino acids include (i) a cysteine at each of four positions corresponding to 1, 20, 34, and 44 of SEQ ID NO: 195; (ii) TALARLR (SEQ ID NO: 169) at positions corresponding to positions 9-15 of SEQ ID NO: 195; (iii) QKKme3 at positions 0 corresponding to positions 24, 25, and 26 of SEQ ID NO: 195; and (iv) QYL at positions corresponding to positions 28, 29, and 30 of SEQ ID NO: 195.

[0240] In some embodiments, the disclosure provides a composition, comprising a Nectin-4 binding polypeptide having an amino acid sequence comprising at least 44 amino acids, wherein the amino acids include (i) a cysteine at each of four positions corresponding5 to 1, 20, 34, and 44 of SEQ ID NO: 200; (ii) TALA(Cit)LR (SEQ ID NO:247) at positions corresponding to positions 9-15 of SEQ ID NO: 200; (iii) QKKme3 at positions corresponding to positions 24, 25, and 26 of SEQ ID NO: 200; and (iv) QYL at positions corresponding to positions 28, 29, and 30 of SEQ ID NO: 200.

[0241] In some embodiments, the disclosure provides a composition, comprising a0 Nectin-4 binding polypeptide having an amino acid sequence, wherein the amino acid sequence comprises: at least four cysteines, which form two disulfide bonds; at least one modified lysine residue at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the modification comprises at least one small alkyl group attached to the nitrogen of the lysine side chain, optionally comprising a methyl, dimethyl, trimethyl, or isopropyl5 group; at least 44 amino acids in length; and has a binding affinity for Nectin-4 stronger than 100 nM in a cell-based assay.

[0242] In some embodiments, the polypeptide is at least 40 amino acids in length, but no greater than 100 amino acids in length. In some embodiments, the polypeptide binds to Nectin-4 with an affinity of stronger than 10 nM in a cell-based assay. 0

[0243] In some embodiments, the amino acid sequence of the polypeptide shares at least 90% identity to any one of SEQ ID NOs: 3-158, 161-168, 177-208, or 212-215, but includes at least one lysine with at least one modification comprising at least one small alkyl group bonded to the nitrogen of the side chain, optionally selected from: trimethyl, dimethyl, monomethyl, and isopropyl. In some embodiments, the amino acid sequence of the IPTS / 128722251.1 Page 50 of 337Docket No.: AKT-031WO polypeptide shares at least 90% identity to at least 44 amino acids of a reference polypeptide, which reference polypeptide is longer than 44 amino acids in length and binds to Nectin-4 with a strength of at least 10 nM on a cell-based assay, and / or has an inhibition constant of no greater than 10 nM. 5

[0244] In some embodiments, the amino acid sequence of the polypeptide shares at least 90% identity to at least 40 amino acids of any one of SEQ ID NOs: 3-158, 161-168, 177-208, or 212-215, provided that the 40 amino acids includes at least four cysteine residues that form two disulfide bridges.

[0245] In some embodiments, the amino acid sequence of the polypeptide shares at least0 90% identity to at least 35 contiguous amino acids of any one of SEQ ID NOs: 3-158, 161- 168, 177-208, or 212-215, provided that the 40 amino acids includes at least four cysteine residues that form two disulfide bridges. In some embodiments, the amino acid sequence of the polypeptide shares 100% identity to at least 44 amino acids of a reference polypeptide, which reference polypeptide is longer than 44 amino acids in length. 5

[0246] In some embodiments, the amino acid sequence shares 90% identity to at least 44 amino acids as set forth in any one of SEQ ID NO: 78, 83, 85, 99, 103, 162-168, 195, or 200.

[0247] In some embodiments, the amino acid sequence shares 100% identity to at least 44 amino acids as set forth in any one of SEQ ID NO: 78, 83, 85, 99, 103, 162-168, 195, or 200.

[0248] In some embodiments, the disclosure provides composition comprising a 0 polypeptide having an amino acid sequence comprising SEQ ID NO: 195.

[0249] In some embodiments, the disclosure provides a composition comprising a compound as set forth in C251 of Table 2A, having an amino acid sequence comprising SEQ ID NO: 195

[0250] In some embodiments, the disclosure provides a composition comprising a5 polypeptide having an amino acid sequence comprising SEQ ID NO: 200.

[0251] In some embodiments, the disclosure provides a composition comprising a compound as set forth in C260 of Table 2A, having an amino acid sequence comprising SEQ ID NO: 200.

[0252] In some embodiments, the composition further comprises a radionuclide. In some0 embodiments, the radionuclide is Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La- 132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

[0253] In some embodiments, the disclosure provides a composition comprising a polypeptide having an amino acid sequence of at least 44 amino acids in length, but with four IPTS / 128722251.1 Page 51 of 337Docket No.: AKT-031WO amino acid substitutions at positions corresponding to 12, 21, 26, and 32 of SEQ ID NO: 78, wherein the substitutions correspond to K12A, Y21Q, S26Kme3, and G32A.

[0254] In some embodiments, the C-terminus has an -OH or an -NH2.

[0255] In some embodiments, the binding affinity of the composition (e.g., the 5 polypeptide) for Nectin-4 is stronger than 100 nM.

[0256] In some embodiments, the inhibition constant is no greater than 100 nM.

[0257] In some embodiments, the composition further comprises one or more of a linker, chelator, and radionuclide.

[0258] In some embodiments, the linker comprises or consists of a polyethylene glycol0 (PEG) linker of PEG4, PEG2, PEG, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)- PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N- maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof. 5

[0259] In some embodiments, the chelator comprises or consists of DOTA, Crown, NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

[0260] In some embodiments, the radionuclide is selected from Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-0 232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

[0261] In some embodiments, if the polypeptide comprises any one of SEQ ID NO: 83, 85, 93, 99, 134, 138, 145, 155, 162-168, or 195 the polypeptide further comprises a linker, wherein the linker is PEG4, and an optional chelator, wherein the chelator is DOTA.

[0262] In some embodiments, when present, the linker is attached to the N-terminus of the5 polypeptide. In some embodiments, when present, the linker is attached to the C-terminus of the polypeptide.

[0263] In some embodiments, the C-terminal amino acid of the polypeptide is not a cysteine.

[0264] In some embodiments, when present, the chelator is attached to either the 0 polypeptide or the linker.

[0265] In some embodiments, when present, the radionuclide is attached to the chelator.

[0266] In some embodiments, the disclosure provides a composition comprising a formula selected from one or more of (M)x-L-C-R, (M)x-L-C, (M)x-C-R, (M)x-L-R, (M)x-C, (M)x- L, and (M)x-R, wherein M comprises a polypeptide (M), L comprises a linker (L), C IPTS / 128722251.1 Page 52 of 337Docket No.: AKT-031WO comprises a chelator (C), R comprises a radionuclide (R), and x is 1, 2, 3, or 4, wherein M comprises an amino acid sequence of any one of SEQ ID NO: 162-176, 178-208, or 212-215.

[0267] In some embodiments, the linker comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-5 PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N- maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof.

[0268] In some embodiments, the chelator comprises or consists of DOTA, Crown,0 NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

[0269] In some embodiments, the radionuclide Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm- 153, Ra-225, Tb-165, or At-211. 5

[0270] In some embodiments, the disclosure provides a composition comprising a formula selected from one or more of (M)x-L-C-R, (M)x-L-C, (M)x-C-R, (M)x-L-R, (M)x-C, (M)x- L, and (M)x-R, wherein M comprises a polypeptide (M), L comprises a linker (L), C comprises a chelator (C), R comprises a radionuclide (R), and x is 1, 2, 3, or 4, wherein M has an amino acid sequence comprising any one of those set forth in SEQ ID NOs: 162-176,0 178-208, or 212-215.

[0271] In some embodiments, when L is present, L comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, lys(MPB)-PEG4, PEG36, an ester linker, an amide linker, a maleimide linker a valine- citrulline linker, a hydrazone linker, a N-succinimidyl-4-(2-pyridyldithio)butyrate (SPDB)5 linker, a succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) linker, a vinylsulfone-based linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof.

[0272] In some embodiments, when C is present, C comprises or consists of DOTA,0 Crown, NOPO, Macropa, lead-specific chelator (PSC), N-succinimidyl 3-(tri-n- butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

[0273] In some embodiments, when R is present, R comprises or consists of Ac-225, Cu- 64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb- 203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211. IPTS / 128722251.1 Page 53 of 337Docket No.: AKT-031WO

[0274] In some embodiments, when present, the linker is attached to the N-terminus of the polypeptide. In some embodiments, when present, the linker is attached to the C-terminus of the polypeptide.

[0275] In some embodiments, the C-terminal amino acid of the polypeptide is not a 5 cysteine.

[0276] In some embodiments, when present, the chelator is attached to either the polypeptide or the linker.

[0277] In some embodiments, when present, the radionuclide is attached to the chelator.

[0278] In some embodiments, the polypeptide comprises at least one disulfide bridge.0

[0279] In some embodiments, the polypeptide comprises at least two disulfide bridges.

[0280] In some embodiments, the composition and / or polypeptide thereof selectively binds to Nectin-4 or a portion thereof.

[0281] In some embodiments, the polypeptide has a binding affinity for Nectin-4 or a portion thereof of 10 pM to 200 nM, 10 pM to 100 nM, or 10 nM to 100 nM, in vivo, ex5 vivo, or in vitro and / or as measured in a cell-based assay.

[0282] In some embodiments, the polypeptide has a binding inhibition constant of no greater than 100 nM.

[0283] A composition comprising a polypeptide-drug conjugate, comprising a polypeptide and at least one drug moiety, wherein the polypeptide comprises an amino acid sequence0 having at least 90% identity to at least 44 amino acids a polypeptide having an amino acid sequence set forth in any one of SEQ ID NOs: 3-158, 162-208, or 212-237.

[0284] In some embodiments, the drug moiety is selected from a V-ATPase inhibitor, a pro-apoptotic agent, a Bcl2 inhibitor, an MCL1 inhibitor, a HSP90 inhibitor, an IAP inhibitor, an mTor inhibitor, a microtubule stabilizer, a microtubule destabilizer, an 5 auristatin, a dolastatin, a maytansinoid, a MetAP (methionine aminopeptidase), an inhibitor of nuclear export of proteins CRMl, a DPPIV inhibitor, proteasome inhibitors, inhibitors of phosphoryl transfer reactions in mitochondria, a protein synthesis inhibitor, a kinase inhibitor, a CDK2 inhibitor, a CDK9 inhibitor, a kinesin inhibitor, an HDAC inhibitor, a DNA damaging agent, a DNA alkylating agent, a DNA intercalator, a DNA minor groove0 binder, a DHFR inhibitor, a topoisomerase inhibitor, an auristatin (e.g., monomethyl auristatin E), and an immunotoxin.

[0285] In some embodiments, the disclosure provides a composition comprising an isolated compound or pharmaceutically acceptable salt thereof comprising an optional linker (L), and one or more of a polypeptide (M), chelator (C) or radionuclide (R), wherein M has IPTS / 128722251.1 Page 54 of 337Docket No.: AKT-031WO an amino acid sequence comprising any one of SEQ ID NOs: 3-158, 161-168, 171-208, 212- 215, or 216-237, including amino acid substitutions as set forth in Table 1C, Table 1D, Table 2C, Table 2D, Table 2E, Table 2F, or Table 2G.

[0286] In some embodiments, the disclosure provides a composition comprising, a 5 compound designed to bind to Nectin-4, which compound comprises or consists of a polypeptide having an amino acid sequence comprising any one of SEQ ID NOs: 3-158, 161- 168, 171-208, 212-215, or 216-237, including amino acid substitutions as set forth in Table 1C, Table 1D, Table 2C, Table 2D, Table 2E, Table 2F, or Table 2G, and further comprises a modified N and / or C-terminus. 0

[0287] In some embodiments, the modified N-terminus comprises one or more of an NH2, Acetyl, PEGn, wherein n=0-10, DOTA, or Biotin.

[0288] In some embodiments, the C terminus comprises an -NH2 or an -OH.

[0289] In some embodiments, the polypeptide selectively binds to Nectin-4 or a portion thereof. 5

[0290] In some embodiments, the polypeptide has a binding affinity of stronger than about 100 nM to Nectin-4, or a portion thereof, in vivo or in a cell-based assay. Nectin-4

[0291] Nectin proteins are involved in cellular adhesion, migration, and polarization. Nectin-4 in most human organs was found to be homogenously expressed at weak to0 moderate levels, but specifically overexpressed in a majority of samples from metastatic urothelial, breast, lung, head / neck, and cervical tumors. One antibody-drug conjugate (ADC), enfortumab vedotin (“EV”; Padcev; Astellas; Tokyo, Japan; and Seattle Genetics; Bothell, WA, USA), specifically targets Nectin-4 that is overexpressed on the surface of bladder tumor cells. EV is conjugated to a microtubule inhibitor (monomethyl auristatin E), which5 causes G2 / M cell cycle arrest and apoptosis. In some embodiments, a miniprotein of the present disclosure targets Nectin-4 on tumor cells. (Bednova O. & Leyton JV. Int J Mol Sci. 2020 Oct 1; 21(19): 7268).

[0292] Clinical trials with EV suggest that, in some embodiments, depending on context (e.g., type of cancer), targeting of Nectin-4 can be all or part of a successful therapeutic0 strategy for treatment of cancer. For example, EV approval in the United States followed PhI and II clinical trial results. In the PhI study, patients who had previously been treated with ICI therapy had an overall tumor objective response rate (ORR) of 42% and patients with particularly high tumor burden (e.g., liver metastases) has a 36% ORR. Furthermore, in the IPTS / 128722251.1 Page 55 of 337Docket No.: AKT-031WO EV PhII trial, patients with locally advanced or metastatic bladder cancer who had been previously treated with platinum-containing chemotherapy or ICI therapy were treated with EV and all tumors were positive for Nectin-4 and all characterized as having a “strong” level of expression. PD-L1 expression was also evaluated but results of EV therapy showed that at 5 10.2 months (median follow up time), the ORR was 44%, with a 12% complete response rate (CRR); PD-L1 status had no impact on ORR or CRR. This study showed that Nectin-4 is a relevant target in bladder cancer, PD-L1 status or therapy does not negatively impact efficacy of Nectin-4-based therapy and provides a targeted alternative or addition to ICI-based therapy. 0

[0293] EV is currently being explored in a Phase III study, as well as developed for a PhII combination study with ICI therapy in cisplatin-ineligible patients. (Bednova O. & Leyton JV. Int J Mol Sci.2020 Oct 1; 21(19): 7268).

[0294] In some embodiments, Nectin-4 is an important target, alone or in conjunction with one or more therapies, for use with a miniprotein of the present disclosure. 5

[0295] In some embodiments, compositions provided by the present disclosure more specifically and effectively target a cell overexpressing Nectin-4 (e.g., a cancer cell) while minimizing or eliminating damage to surrounding cells not expressing or overexpressing Nectin-4 by providing a targeted composition including, in some embodiments, a chelator and / or alpha-emitter, which when combined with a miniprotein as provided herein provide0 specific, efficient and effective approaches to target cells overexpressing Nectin-4.

[0296] Importantly, novel compositions provided by the present disclosure are capable of specifically, efficiently, and effectively targeting Nectin-4 overexpressing cells with reduced toxicity as compared to presently available treatments. That is, in some embodiments, a composition targeting Nectin-4 as provided by the present disclosure provides improved5 treatment as compared to presently available treatments.

[0297] In some embodiments, a target of compositions of the present disclosure comprises or consists of Nectin-4. In some embodiments, a material change in a basic and novel characteristic of a polypeptide provided herein is the ability to strongly and specifically bind to its intended target (e.g., Nectin-4, e.g., Nectin-4 on a cancer cell) with minimal or no off-0 target effects and minimal kidney uptake (e.g., as compared to kidney uptake of previously developed Nectin-4 binding molecules). In some embodiments, Nectin-4 is expressed on the surface of a cell. In some embodiments, the cell is a cancer cell. In some such embodiments, the cancer cell is a tumor cell and the tumor is a solid tumor. In some embodiments, a level of Nectin-4 expressed in a tumor cell or population of tumor cells is higher than that IPTS / 128722251.1 Page 56 of 337Docket No.: AKT-031WO expressed in non-tumor cells. In some embodiments, targeting of Nectin-4 by a miniprotein or composition comprising a miniprotein as provided by the present disclosure specifically targets a composition or one or more components thereof (e.g., a chelator and / or radionuclide) to a cancer cell or a tumor microenvironment (e.g., a location comprising a 5 population of cancer cells or cells at risk of becoming cancer cells).

[0298] In some embodiments, miniproteins in accordance with the present disclosure specifically bind to Nectin-4. Without limitation, exemplary Nectin-4 miniproteins are provided in TABLE 2A and exemplary Nectin-4 sequences are shown in TABLE 1A.

[0299] In some embodiments, a miniprotein of the present disclosure comprises or0 consists of a polypeptide sequence corresponding to a polypeptide sequence shown in the TABLES 1B, 1C, and / or 2A or binding to a polypeptide as shown in TABLE 1A. In some embodiments, a miniprotein comprises or consists of an amino acid sequence having sequence at least 85% identical to a polypeptide sequence shown in the TABLE(s). In some embodiments, a miniprotein of the present disclosure has at least 70%, 80%, 85%, 90%,5 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or higher identity to a polypeptide sequence according to TABLES 2A, 1B, 1C and / or 1D.

[0300] In some embodiments, compositions in accordance with the present disclosure specifically bind to Nectin-4 (e.g., through a miniprotein that specifically binds to Nectin-4). 0 In some embodiments, a target is Nectin-4. In some such embodiments, a compound targeting Nectin-4 is disclosed in TABLE 1B.

[0301] In some embodiments, a composition comprising a miniprotein comprises or consists of a protein comprising a specific an amino acid sequence that binds to Nectin-4 or a portion thereof. In some embodiments, certain exemplary Nectin-4 binding miniproteins are5 In some such embodiments, such a Nectin-4 miniprotein comprises or consists of an amino acid sequence selected from any of SEQ ID NOs: 93, 99, 134, 138, 145, 155, and 178-215 or a functional variant or portion thereof (e.g., a functional fragment, e.g., a miniprotein that folds and binds to Nectin-4 or a portion thereof). In some embodiments, such a Nectin-4 miniprotein is a binding protein or part of a conjugate comprising such a binding protein as0 set forth in TABLE 2A. In particular embodiments, such a Nectin-4 miniprotein comprises or consists of an amino acid sequence selected from any of SEQ ID NOs: 99, 195, or 200 or a functional variant or portion thereof (e.g., a functional fragment, e.g., a miniprotein that folds and binds to Nectin-4 or a portion thereof). In some embodiments a Nectin-4 miniprotein comprises or consists of an amino acid sequence that is 80%, 85%, 90%, 95%, 96%, 97%, IPTS / 128722251.1 Page 57 of 337Docket No.: AKT-031WO 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9% or more identical to any one of SEQ ID NOs: 93, 99, 134, 138, 145, 155, or 178-215 or a functional variant or portion thereof. In some embodiments a Nectin-4 miniprotein comprises or consists of an amino acid 5 sequence that is 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9% or more identical to any one of SEQ ID NOs: 99, 195, or 200 or a functional variant or portion thereof.

[0302] In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino0 acid sequence according to SEQ ID NO: 3. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 4. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 5. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 6. In some embodiments, a5 Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 7. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 8. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 9. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence0 according to SEQ ID NO: 10. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 11. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 12. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 13. In some embodiments, a Nectin-4 miniprotein5 comprises or consists of an amino acid sequence according to SEQ ID NO: 14. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 15. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 16. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID0 NO: 17. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 18. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 19. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 20. In some embodiments, a Nectin-4 miniprotein comprises or IPTS / 128722251.1 Page 58 of 337Docket No.: AKT-031WO consists of an amino acid sequence according to SEQ ID NO: 21. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 22. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 23. In some embodiments, a Nectin-4 miniprotein 5 comprises or consists of an amino acid sequence according to SEQ ID NO: 24. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 25. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 26. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID0 NO: 27. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 28. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 29. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 30. In some embodiments, a Nectin-4 miniprotein comprises or5 consists of an amino acid sequence according to SEQ ID NO: 31. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 32. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 33. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 34. In some0 embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 35. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 36. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 37. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino5 acid sequence according to SEQ ID NO: 38. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 39. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 40. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 41. In some embodiments, a0 Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 42. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 43. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 44. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence IPTS / 128722251.1 Page 59 of 337Docket No.: AKT-031WO according to SEQ ID NO: 45. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 46. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 47. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino 5 acid sequence according to SEQ ID NO: 48. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 49. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 50. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 51. In some embodiments, a0 Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 52. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 53. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 54. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence5 according to SEQ ID NO: 55. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 56. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 57. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 58. In some embodiments, a Nectin-4 miniprotein0 comprises or consists of an amino acid sequence according to SEQ ID NO: 59. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 60. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 61. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID5 NO: 62. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 63. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 64. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 65. In some embodiments, a Nectin-4 miniprotein comprises or0 consists of an amino acid sequence according to SEQ ID NO: 66. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 67. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 68. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 69. In some IPTS / 128722251.1 Page 60 of 337Docket No.: AKT-031WO embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 70. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 71. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID 5 NO: 72. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 73. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 74. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 75. In some embodiments, a Nectin-4 miniprotein comprises or0 consists of an amino acid sequence according to SEQ ID NO: 76. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 77. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 78. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 79. In some5 embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 80. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 81. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 82. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino0 acid sequence according to SEQ ID NO: 83. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 84. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 85. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 86. In some embodiments, a5 Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 87. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 88. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 89. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence0 according to SEQ ID NO: 90. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 91. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 92. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 93. In some embodiments, a Nectin-4 miniprotein IPTS / 128722251.1 Page 61 of 337Docket No.: AKT-031WO comprises or consists of an amino acid sequence according to SEQ ID NO: 94. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 95. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 96. In some embodiments, a 5 Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 97. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 98. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 99. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence0 according to SEQ ID NO: 100. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 101. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 102. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 103. In some embodiments, a Nectin-4 miniprotein5 comprises or consists of an amino acid sequence according to SEQ ID NO: 104. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 105. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 106. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID0 NO: 107. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 108. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 109. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 110. In some embodiments, a Nectin-4 miniprotein comprises or5 consists of an amino acid sequence according to SEQ ID NO: 111. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 112. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 113. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 114. In some0 embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 115. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 116. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 117. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino IPTS / 128722251.1 Page 62 of 337Docket No.: AKT-031WO acid sequence according to SEQ ID NO: 118. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 119. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 120. In some embodiments, a Nectin-4 miniprotein comprises or 5 consists of an amino acid sequence according to SEQ ID NO: 121. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 122. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 123. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 124. In some0 embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 125. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 126. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 127. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino5 acid sequence according to SEQ ID NO: 128. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 129. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 130. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 131. In some embodiments, a0 Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 132. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 133. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 134. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence5 according to SEQ ID NO: 135. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 136. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 137. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 138. In some embodiments, a Nectin-4 miniprotein0 comprises or consists of an amino acid sequence according to SEQ ID NO: 139. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 140. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 141. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID IPTS / 128722251.1 Page 63 of 337Docket No.: AKT-031WO NO: 142. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 143. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 144. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence 5 according to SEQ ID NO: 145. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 146. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 147. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 148. In some embodiments, a Nectin-4 miniprotein0 comprises or consists of an amino acid sequence according to SEQ ID NO: 149. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 150. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 151. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID5 NO: 152. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 153. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 154. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 155. In some embodiments, a Nectin-4 miniprotein comprises or0 consists of an amino acid sequence according to SEQ ID NO: 156. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 157. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 158. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 161. In some5 embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 162. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 163. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 164. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino0 acid sequence according to SEQ ID NO: 165. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 166. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 167. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 168. In some embodiments, a IPTS / 128722251.1 Page 64 of 337Docket No.: AKT-031WO Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 177. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 178. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 179. In some 5 embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 180. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 181. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 182. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino0 acid sequence according to SEQ ID NO: 183. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 184. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 185. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 186. In some embodiments, a5 Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 187. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 188. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 189. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence0 according to SEQ ID NO: 190. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 191. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 192. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 193. In some embodiments, a Nectin-4 miniprotein5 comprises or consists of an amino acid sequence according to SEQ ID NO: 194. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 195. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 196. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID0 NO: 197. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 198. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 199. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 200. In some embodiments, a Nectin-4 miniprotein comprises or IPTS / 128722251.1 Page 65 of 337Docket No.: AKT-031WO consists of an amino acid sequence according to SEQ ID NO: 201. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 202. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 203. In some embodiments, a Nectin-4 miniprotein 5 comprises or consists of an amino acid sequence according to SEQ ID NO: 204. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 205. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 206. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID0 NO: 207. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 208. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 212. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 213. In some embodiments, a Nectin-4 miniprotein comprises or5 consists of an amino acid sequence according to SEQ ID NO: 214. In some embodiments, a Nectin-4 miniprotein comprises or consists of an amino acid sequence according to SEQ ID NO: 215.

[0303] In some embodiments, a Nectin-4 binding miniprotein comprises or consists of an amino acid sequence according to any one of SEQ ID NOs: 3-158, 161-168, 177-208, or 212-0 215 and can have different N- and / or C-terminal ends, such as, for example, an Acetyl, NH2, Biotin-PEG4, DOTA-PEG4, radiolabel, etc. on its N-terminus and an -OH or -NH2 on its C- terminus. N- and / or C-termini of Nectin-4 binding miniproteins of the disclosure can include but are not limited to acetyl, acid, or amide (e.g., Acetyl, NH2, OH), such as provided in exemplary compounds and miniproteins of TABLE 2A. In some embodiments, a polypeptide5 according to the disclosure may have various modifications to its N-terminus (e.g., a linker, chelator, and / or radionuclide, e.g., such as set forth in exemplary compounds in TABLE 2A) or its C-terminus (e.g., a linker, chelator, and / or radionuclide). In some embodiments, the C- terminus of a given polypeptide can have an acid or amide group on its C-terminus (see, e.g., TABLE 2A). A given polypeptide having a particular amino acid sequence can have one or0 more N-terminal and / or C-terminal differences without materially changing the utility or function of the polypeptide, such as for binding to Nectin-4 (e.g., for detection and / or treatment of cancer).

[0304] In some embodiments, a decoy comprises or consists of an amino acid sequence according to SEQ ID NO: 209. In some embodiments, a decoy comprises or consists of an IPTS / 128722251.1 Page 66 of 337Docket No.: AKT-031WO amino acid sequence according to SEQ ID NO: 210. In some embodiments, a decoy comprises or consists of an amino acid sequence according to SEQ ID NO: 211.

[0305] In some embodiments a Nectin-4 miniprotein comprises or consists of an amino acid sequence that is 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 5 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9% or more identical to any one of SEQ ID NOs: 78, 93, 99, 134, 138, 145, 155, 161-168, 177-208, or 212-215 or a functional variant or portion thereof. In some embodiments a Nectin-4 miniprotein comprises or consists of an amino acid sequence that is 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%,0 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9% or more identical to any one of SEQ ID NOs: 78, 93, 99, 134, 138, 145, 155, 194, 195, 200, 203, or 204 or a functional variant or portion thereof. In some embodiments a Nectin-4 miniprotein comprises or consists of an amino acid sequence that is 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%,5 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9% or more identical to any one of SEQ ID NOs: 99, 195, and 200 or a functional variant or portion thereof. In some embodiments, a miniprotein of SEQ ID NOs: 216-237 has one or more substitutions as set forth in TABLE 1C. In some embodiments, a miniprotein of SEQ ID NOs: 170-176 or 243- 246 and has one or more substitutions as set forth in TABLE 1D. In some embodiments, a0 Nectin-4 miniprotein comprises or consists of an amino acid sequence that is 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9% or more identical to any one of SEQ ID NOs: 216-237 or a functional variant or portion thereof having one or more substitutions as set forth in TABLE 1C, TABLE 2C, TABLE 2D,5 TABLE 2E, TABLE 2E, TABLE 2F, or TABLE 2G.

[0306] In some embodiments, the present disclosure provides a polynucleotide encoding a polypeptide that comprises or consists of one or more portions of a composition as provided herein. In some embodiments, the present disclosure provides a vector and / or host cell comprising a sequence encoding one or more components of a composition as provided0 herein. In some embodiments, the present disclosure provides methods of detecting a target. In some embodiments, a method as provided herein comprises detecting presence of a target for, e.g., imaging, e.g., diagnostic, prognostic, and / or monitoring purposes, e.g., treatment. In some embodiments, the present disclosure provides methods of treatment and / or methods of manufacturing using composition as provided herein (e.g., a miniprotein, e.g., a linker- IPTS / 128722251.1 Page 67 of 337Docket No.: AKT-031WO chelator, e.g., a miniprotein comprising one or more of a linker, chelator, and radionuclide, etc.). In some embodiments, a method of treatment comprises administering a composition as provided herein to a subject in need thereof. Polypeptides 5

[0307] Among other things, the present disclosure provides polypeptides. In some embodiments a polypeptide is assembled using solid phase synthesis methods. In some embodiments, a polypeptide is recombinant. In some embodiments, a polypeptide comprises or consists of a miniprotein. In some such embodiments, a miniprotein comprises or consists of a binder. In some embodiments, polypeptides of the present disclosure (including muteins,0 allelic variants, fragments, derivatives, and analogs) are encoded by polynucleotides as described and provided herein.

[0308] In some embodiments, a polypeptide has an amino acid sequence that is 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%,5 99.9%, or 100% identical to a portion of an amino acid sequence set forth in TABLE 2A. For example, in some embodiments, a polypeptide has an amino acid sequence that is 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, or 44 amino acids of a0 given polypeptide such as those set forth in TABLE 2A. In some embodiments, a polypeptide has an amino acid sequence that is 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to 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, 35,5 36, 37, 38, 39, 40, 41, 42, 43, 44 or 45 contiguous amino acids of a given polypeptide such as those set forth in TABLE 2A.

[0309] In some embodiments, a polypeptide is a miniprotein. In some such embodiments, the miniprotein is capable of binding to a target (e.g., Nectin-4 or a portion thereof) as provided herein. 0

[0310] In some embodiments, a miniprotein of the present disclosure comprises or consists of a polypeptide capable of binding to target as shown in TABLE 1A.

[0311] In some embodiments, the present disclosure provides binders comprising or consisting of a fragment of a polypeptide as provided herein. In some such embodiments, IPTS / 128722251.1 Page 68 of 337Docket No.: AKT-031WO fragments include at least 20 contiguous amino acids, more preferably at least 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or more contiguous amino acids.

[0312] In some embodiments, miniproteins of the present disclosure can also include fusions or conjugates with one or more other components, such as heterologous polypeptides. 5 For example, in some embodiments, heterologous sequences can comprise or consist of sequences designed to facilitate purification, e.g., histidine tags, and / or visualization of recombinantly-expressed proteins. Other non-limiting examples of such fusions or conjugates include those that permit display of the encoded protein on the surface of a phage or a cell, including any detectable or visualizable component such as, e.g., green fluorescent protein0 (GFP), and fusions to the IgG Fc region.

[0313] In some embodiments, a miniprotein comprises or consists of a specific amino acid sequence. In some embodiments, a miniprotein has an amino acid sequence that is 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%,5 99.9%, or 100% identical to the amino acid sequence set forth in any of SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246, 248 and / or according to TABLES 1B and / or 1C, 1D and / or 2A.

[0314] In some embodiments, a miniprotein has an amino acid sequence that is 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%,0 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to the amino acid sequence set forth in any amino acid sequences set forth in TABLE 2A.

[0315] In some embodiments, a miniprotein has an amino acid sequence that is 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%,5 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to a portion or all of an amino acid sequence set forth in TABLE 2A. For example, in some embodiments, a miniprotein has an amino acid sequence that is 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%,0 99.9%, or 100% identical to 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, or 44 amino acids of a given polypeptide such as those set forth in TABLE 2A. In some embodiments, a miniprotein has an amino acid sequence that is 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to 5, 6, 7, 8, 9, 10, IPTS / 128722251.1 Page 69 of 337Docket No.: AKT-031WO 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 or 45 contiguous amino acids of a given polypeptide such as those set forth in TABLE 2A.

[0316] In some embodiments, a polypeptide (e.g., a miniprotein) has an amino acid 5 sequence with a certain percent identity over a certain percent coverage (e.g., of a reference sequence). That is, a Nectin-4 binding polypeptide (e.g., a reference molecule) as provided herein can have 70, 75, 80, 85, 90, 95, 99, or 100 percent identity to a given query but over a percent coverage of that molecule (e.g., 10, 20, 30, 40, 50, 60, 70, 80, 90, 100%), where if the query molecule is shorter it may have a percent identity and a percent coverage that are0 different (e.g., 100% identity and 90% coverage). If the query molecule is longer, than the percent identity and coverage could each be 100% with respect to the reference molecule, and the reference molecule would have a percent identity over a length (e.g., at least 20, 25, 30, amino acids) of the query molecule. For example, in some embodiments, if a reference sequence (e.g., a miniprotein as provided herein) is shorter than a query sequence, such a5 query sequence is within the scope of the present disclosure if it has a length of reference sequence that aligns with the query sequence, wherein the percent identity is determined over at least a minimum length of the alignment between the two sequences (query and reference). That is, if a polypeptide disclosed herein is longer than a query sequence, a percent identity is determined by aligning the reference and query and determining the percent identity as0 between the query and the portion of the reference sequence over which it aligns. Conversely, where a query sequence is longer than a reference sequence, percent identity equals an identity over an aligned portion with the reference sequence. That is, if the reference sequence is shorter, the query sequence can fall within the scope of a reference sequence if it aligns at a claimed percent identity over the aligned portion between the two5 polypeptides (reference and query).

[0317] As used herein and known to those of skill in the art, the twenty conventional amino acids and their abbreviations follow conventional usage. See Immunology-A Synthesis (Golub and Gren eds., Sinauer Associates, Sunderland, Mass., 2nd ed.1991), which is incorporated herein by reference. In some embodiments, an amino acid of the0 present disclosure may be a stereoisomer (e.g., D-amino acids) of the twenty conventional amino acids. In some embodiments, an amino acid in a polypeptide of the present disclosure may be a non-natural amino acid. For example, amino acids such as Į-, Į-disubstituted amino acids, N-alkyl amino acids, and other unconventional amino acids may also be suitable components for polypeptides of the present disclosure. Examples of unconventional amino IPTS / 128722251.1 Page 70 of 337Docket No.: AKT-031WO acids include: 4-hydroxyproline, Ȗ-carboxyglutamate, İ-N-monomethyllysine, İ-N,N- dimethyllysine, İ-N,N,N-trimethyllysine, İ-N-acetyllysine, İ-N-isopropyl-lysine, O- phosphoserine, N-acetylserine, N-formylmethionine, 3-methylhistidine, 5-hydroxylysine, N- methylarginine, and other similar amino acids and imino acids (e.g., 4-hydroxyproline). 5 Arrangements of polypeptide sequence notations used herein have a left-side end corresponding to the amino terminal and a right-side end corresponding to the carboxy- terminal end, in accordance with standard usage and convention.

[0318] In some embodiments, miniproteins of the present disclosure comprising two or more cysteine residues, such as those set forth in TABLE 2A, have cysteine residues0 connected via disulfide bridges (e.g., via natural folding).

[0319] In some embodiments, cysteine connections are between positions corresponding to Cys1 and Cys34; and Cys20 and Cys44 of a reference sequence such as set forth in TABLE 2A (e.g., SEQ ID NO: 195). In some embodiments, cysteine connections are between Cys1 and Cys20; and Cys34 and Cys44. In some embodiments, cysteine 5 connections are between Cys1 and Cys44; and Cys20 and Cys34.

[0320] In some embodiments, In some embodiments, the disulfide bridge or bridges comprise two or four cysteines at positions corresponding to 1, 20, 34, and 44 of SEQ ID NO: 195, wherein the cysteine corresponding to position 1 can form a disulfide bridge with the cysteine corresponding to position 20, 34, or 44. In some embodiments, the cysteine0 corresponding to position 20 can form a disulfide bridge with the cysteine corresponding to position 1, 34, or 44. In some embodiments, the cysteine corresponding to position 34 can form a disulfide bridge with the cysteine corresponding to position 1, 20, or 44. In some embodiments, the cysteine corresponding to position 44 can form a disulfide bridge with the cysteine corresponding to position 1, 20, or 44. In some embodiments, where four cysteines5 are present and correspond to positions 1, 20, 34, and 44 of SEQ ID NO: 195, pairings can comprise 1 paired with 34 and 20 paired with 44, 1 paired 20 and 34 paired with 44, or 1 paired with 44 and 20 paired with 34 (e.g., disulfide bridges between the two cysteines of the pair).

[0321] In some embodiments, the present disclosure provides a miniprotein comprising or0 consisting of an amino acid sequence set forth in SEQ ID NO: 3-158, 161-168, 170-208, 212-237, 243-246, 248 and / or as set forth in TABLES 1B, 1C, 1D, and / or 2A or a portion or functional variant thereof. In some embodiments, a miniprotein comprises or consists of an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, IPTS / 128722251.1 Page 71 of 337Docket No.: AKT-031WO 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or greater sequence identity to SEQ ID NO: 3-158, or 177-237 and / or as set forth in TABLES 1B, 1C, 1D, and / or 2A or a portion or functional variant thereof. In some embodiments, the miniprotein comprises or consists of an amino acid sequence having at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at 5 least 8, at least 9, at least 10, at least 15, at least 20 or more amino acid residue differences from SEQ ID NO: 3-158, 161-168, 170-208, 212-237, 243-246, 248 and / or as set forth in TABLES 1B, 1C, 1D, and / or 2A or a portion or functional variant thereof. In some embodiments, the miniprotein comprises or consists of an amino acid sequence having no more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acid residue0 differences from SEQ ID NO: 3-158, 161-168, 170-208, 212-237, 243-246, 248 and / or as set forth in TABLES 1B, 1C, 1D, and / or 2A or a portion or functional variant thereof. In some embodiments, the miniprotein comprising or consisting of SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246, 248 and / or as set forth in TABLES 1B, 1C, 1D, and / or 2A or a portion or functional variant thereof selectively binds to the target Nectin-4. 5

[0322] Polypeptides of the disclosure may have one or more modifications. A modification can refer to an amino acid sequence that comprises at least one substitution, alteration, inversion, addition, or deletion of an amino acid residue compared to a reference amino acid sequence. An alteration can include but is not limited to a change to or of one or more atoms of a side chain, such as, for example addition of a methyl-group (e.g., methylated0 versions of lysine). In some embodiments, a natural amino acid is modified such as set forth herein. In some embodiments, a modification includes addition of at least one small alkyl group attached to the nitrogen of an amino acid side chain, such as, for example, a lysine side chain. As used herein, a “small alkyl group” refers to an alkyl group with a short carbon chain, typically having one to four carbon atoms, such as methyl, ethyl, propyl, or butyl, and5 also including, for example, dimethyl, trimethyl, isopropyl, etc. In some embodiments, for example, one or more small alkyl groups can be added to the nitrogen of a lysine side chain to produce monomethyl, dimethyl, or trimethyllysine. In some embodiments, one, two, three, four or more small alkyl groups may be added to a given amino acid (e.g., through attachment to the nitrogen of the side chain). In some embodiments no more than five, four,0 three, two, or one small alkyl groups are added. Miniproteins

[0323] Provided herein are novel polypeptides (i.e., miniproteins) and methods of use thereof. In some embodiments, a polypeptide comprises or consists of a miniprotein. In some such embodiments, the miniprotein comprises or consists of a CDP, knottin, and / or binder. In some embodiments the miniprotein is designed to be linked to one or more other IPTS / 128722251.1 Page 72 of 337Docket No.: AKT-031WO components. For example, in some embodiments, a miniprotein may be linked (conjugated) to another component such as a chelator and / or a radionuclide. In some embodiments, conjugation is via a lysine or cysteine residue. For example, in some embodiments, a miniprotein is engineered to remove all lysine residues except for one, which is, in some 5 embodiments, used for conjugation. In some embodiments, conjugation occurs via an optional linker. In some embodiments, conjugation between a miniprotein and a chelator and / or radionuclide is direct.

[0324] Without wishing to be bound by any particular theory, the present disclosure contemplates that therapeutics comprising compositions provided by the present disclosure0 are characterized by several features relative to other (e.g., antibody-based) therapeutics. For example, in some embodiments, miniproteins display several key features of antibody-based therapeutics (e.g., affinity, potency, specificity, and ability to disrupt protein:protein interactions) but also have several advantages as compared to antibody-based therapeutics such as smaller size, cheaper manufacturing, and elimination of need to chimerize or5 humanize the proteins. In addition, the size and specificity of binding increases tumor penetrance and uptake into cells expressing the target of the miniprotein or composition (e.g., conjugate) comprising a miniprotein.

[0325] In some embodiments, a miniprotein of the present disclosure is no more than about 100 amino acids in length. In some embodiments, a miniprotein is about 20, 25, 30, 35,0 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or more amino acids in length, up to about 100 amino acids in length. In some such embodiments, however, a miniprotein of the present disclosure does not exceed about 100 amino acids in length. In some embodiments a miniprotein is between about 20 to about 40, about 30 to about 50, about 40 to about 60, about 45 to about 65, about 50 to about 70, about 55 to about 75, about 65 to about 85 or5 more amino acids in length, but not exceeding about 100 amino acids in length. In some preferred embodiments, a miniprotein is about 65 amino acids or less. In some preferred embodiments, a miniprotein is about 50 amino acids or less.

[0326] In some embodiments, a miniprotein of the present disclosure is not larger than about 12 kDa. In some embodiments, a miniprotein of the present disclosure is about 2, 2.5,0 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5 or more kDa. In some such embodiments, however, a miniprotein of the present disclosure does not exceed about 12 kDa.

[0327] In some embodiments, a miniprotein comprises one or more disulfide bridges. In some embodiments, a miniprotein comprises at least two disulfide bridges. In some IPTS / 128722251.1 Page 73 of 337Docket No.: AKT-031WO embodiments, a miniprotein comprises at least three cysteine residues. In some embodiments, a miniprotein comprises multiple (e.g., more than three) cysteine residues. In some such embodiments, cysteine residues crosslink to maintain a very stable, folded state for a peptide of its length (e.g., relative to a peptide of the same length without as many cysteine residues). 5 The present disclosure contemplates that such crosslinking confers improved stability with reduced (i.e., very low to no) immunogenicity and / or sustains or improves ability to maintain biological activity in harsh but efficient chelation conditions (e.g., high temperature and low pH).

[0328] In some embodiments a miniprotein or composition comprising a miniprotein (e.g.,0 a radionuclide conjugate) has low immunogenicity relative to a larger protein or composition comprising or consisting of a larger protein (e.g., an antibody).

[0329] In some embodiments, miniproteins (e.g., a linear polypeptide, a folded polypeptide (e.g., covalently linked polypeptide, non-covalently linked polypeptide, or polypeptide include a di-sulfide linkage), cysteine-dense peptide, a knottin peptide, a binder,5 an affibody, an engineered Kunitz domain, a monobody, an anticalin, a designed ankyrin repeat domain (DARPin), or an avimer) have superior penetration efficiency relative to larger proteins. That is, in some embodiments, a miniprotein or composition comprising a miniprotein can penetrate a solid tumor better than a larger protein or composition comprising a protein larger than a miniprotein. For example, in some such embodiments, a0 miniprotein or composition comprising a miniprotein has a hydrodynamic radius of about 1 to about 25 nm. In some embodiments, a hydrodynamic radius is in a range of about 1-25 nm, 10-20 nm, 5-15 nm, 1-5 nm, 2-4 nm, or 1-3 nm. In some embodiments, hydrodynamic radius is measured using light scatter methods known to those of skill in the art.

[0330] In some embodiments, a miniprotein of the present disclosure is characterized in5 that it has one or more properties relative to a protein larger than 100 amino acids like an antibody, antibody fragment, VHH domain, single chain antibody, or other protein or binder greater than 12 kDa. In some embodiments a property is selected from increased protein expression, increased thermoactivity, increased thermostability, increased pH activity, increased stability, increased activity, increased receptor binding specificity and / or affinity,0 increased specific activity, increased resistance to substrate and / or end-product inhibition, increased chemical stability, improved chemoselectivity, improved solvent stability, increased tolerance to acidic pH, increased tolerance to proteolytic activity (i.e., reduced sensitivity to proteolysis), reduced aggregation, increased solubility, reduced immunogenicity, and altered temperature profile, increased resistance to liver uptake, kidney IPTS / 128722251.1 Page 74 of 337Docket No.: AKT-031WO uptake or healthy tissue binding, decreased binding to megalin and / or cubulin, increased tumor penetration, and / or increased volume of distribution.

[0331] In some embodiments, a miniprotein or composition comprising a miniprotein (e.g., conjugate, e.g., radionuclide conjugate) provided by the present disclosure exhibits 5 binding affinity to Nectin-4. In some embodiments, the Nectin-4 is human Nectin-4. In some embodiments, the human Nectin-4 is on a cell. In some embodiments, the cell is a cell line, a primary cell, or a cell in a human (e.g., in a tumor).

[0332] In some embodiments, a miniprotein or composition comprising a miniprotein (e.g., conjugate, e.g., radionuclide conjugate) displays nM or sub-nM binding affinity to0 Nectin-4. In some embodiments, the affinity is measured in an in vitro assay. In some embodiments, the in vitro assay is a cell-based assay. In some embodiments, affinity is measured in an in vivo assay (e.g., a PET scan) or using a sample from a subject (e.g., an in vitro assay using a biological specimen such as blood or a cell biopsy from a subject).

[0333] In some embodiments, a miniprotein or conjugate thereof displays a binding5 affinity to Nectin-4 (KD or Kd). In some embodiments, the binding affinity of a miniprotein or conjugate thereof to human Nectin-4 is about 500 nM, 400 nM, 300 nM, 200 nM, 100 nM, or stronger (e.g., 90 nM, 75 nM, 50 nM, 25 nM, 10 nM, 5 nM, etc.). In some embodiments, the miniprotein comprises picomolar binding affinity. In some embodiments, the miniprotein or conjugate thereof comprises a binding affinity characterized by a dissociation constant0 ranging from about 900 nM to about 1 nM, e.g., 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4 nM or stronger (e.g., 0.3, 0.2, 0.1 nM, etc.) binding affinity to human Nectin-4. In some embodiments, the binding is selective to human Nectin-4 and, not, e.g., non-human Nectin-4.

[0334] In some embodiments, a miniprotein or conjugate thereof displays a binding5 inhibition constant. In some embodiments, the binding inhibition constant (Ki) to human Nectin-4 is about 300 nM, 200 nM, 100 nM, 50 nM, 25 nM, 10 nM, 5 nM, or less (e.g., 1 nM, etc.). In some embodiments, the miniprotein comprises picomolar binding affinity. In some embodiments, the miniprotein or conjugate thereof comprises a binding affinity characterized by a dissociation constant ranging from about 900 nM to about 1 nM, e.g., 900,0 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4 nM or stronger (e.g., 0.3, 0.2, 0.1 nM, etc.) binding affinity to human Nectin-4. In some embodiments, the binding is selective to human Nectin-4 and, not, e.g., non-human Nectin-4. IPTS / 128722251.1 Page 75 of 337Docket No.: AKT-031WO

[0335] In some embodiments, a miniprotein or conjugate thereof provided by the present disclosure has high affinity for Nectin-4 (e.g., as measured by binding affinity and / or inhibition constant, etc.). In some such embodiments, the Nectin-4 is human Nectin-4. In some embodiments, a miniprotein of the present disclosure is stable, including in the 5 presence of one or more additional molecules (e.g., a cytotoxic molecule, e.g., radiation).

[0336] In some embodiments, binding ability of a miniprotein or conjugate thereof to a target is improved by one or more modifications. For example, in some embodiments, binding ability of a miniprotein or conjugate thereof as provided herein to Nectin-4, is improved using chemical crosslinking. In some embodiments, binding can be enhanced by0 using one or more of lysine residues, fusion proteins, non-natural amino acids, or other chemical moieties to enhance binding and / or functional activity.

[0337] In some embodiments, to ensure proper folding and connectivity, selected cysteine pairs can be replaced with selenocysteines. It is contemplated that, in some embodiments, diselenide crosslinks can form more readily than disulfide crosslinks due to their lower redox5 potential and such a replacement may cross-couple remaining cysteine residues.

[0338] In some embodiments, a miniproteins or conjugates thereof provided by the present disclosure comprises or consists of monomers that make up a dimer, polymer or a multimer. In some such embodiments, the monomers all bind to the same target. For example, in some embodiments, where more than one miniprotein is present, each 0 miniprotein is no greater than about 30-40 amino acids in length or a total of about 8 kDa in size (with both miniproteins). In some embodiments, the monomers each bind to a different target. In some embodiments, some monomers bind to one target and others bind to one or more additional targets.

[0339] In some embodiments, a miniprotein of the present disclosure comprises or5 consists of an antigen for use in generating an antibody that specifically binds to at least one epitope on Nectin-4. In some embodiments, such an antibody may be used for, e.g., diagnostic purposes, blocking (e.g., antagonism), etc.

[0340] In some embodiments, the miniprotein comprises one or more disulfide bridges. In some embodiments, the miniprotein comprises at least two disulfide bridges. 0

[0341] In some embodiments, a miniprotein or conjugate thereof as provided herein does not comprise one or more cysteine residues. In some embodiments, the miniprotein does not comprise one or more disulfide bridges. IPTS / 128722251.1 Page 76 of 337Docket No.: AKT-031WO

[0342] In some embodiments, a miniprotein or conjugate thereof as provided herein is specific for a target. In some embodiments, a miniprotein is specific for Nectin-4 or a fragment thereof.

[0343] In some embodiments, a miniprotein or conjugate thereof as provided herein 5 comprises or consists of a specific amino acid sequence.

[0344] In some embodiments, miniproteins or compositions comprising miniproteins (e.g., radionuclide conjugates) are conjugated to a chelator that optionally binds a radionuclide (e.g., actinium). In some embodiments, the conjugation is via a linker. In some embodiments, conjugation is direct conjugation. In some embodiments, such radionuclide0 conjugates combine and synergize to provide target specificity (e.g., via the miniprotein) and superior treatment (e.g., via directed radioisotope delivery to the cell expressing the target).

[0345] In some embodiments, miniproteins or compositions comprising miniproteins are conjugated to a chelator that optionally binds a cold-metal surrogate. In some embodiments, a cold-metal surrogate is a natural isotope of an element that is not radioactive. In some5 embodiments, an element may have more than one natural isotope that is not radioactive. In some embodiments, “cold” is used to refer to an isotype of an element that is not radioactive. In some embodiments, “hot” refers to an isotope of an element that is radioactive.

[0346] As used herein and known to those of skill in the art, the twenty conventional amino acids and their abbreviations follow conventional usage. See Immunology-A 0 Synthesis (Golub and Gren eds., Sinauer Associates, Sunderland, Mass., 2nd ed.1991), which is incorporated herein by reference. In some embodiments, an amino acid of the present disclosure may be a stereoisomer (e.g., D-amino acids) of the twenty conventional amino acids. In some embodiments, an amino acid in a polypeptide of the present disclosure may be a non-natural amino acid. For example, amino acids such as Į-, Į-disubstituted amino5 acids, N-alkyl amino acids, and other unconventional amino acids may also be suitable components for polypeptides of the present disclosure. Examples of unconventional amino acids include: 4-hydroxyproline, Ȗ-carboxyglutamate, trimethyllysine, İ-N,N,N- trimethyllysine, İ-N-acetyllysine (Lys(Ac)), O-phosphoserine, N-acetylserine, N- formylmethionine, 3-methylhistidine, 5-hydroxylysine, N-methylarginine, norleucine,0 citrulline, L-citrulline, symmetrically dimethylated arginine (sRme2, Rme2s, or SDMA), nitroarginine (Arg(NO2)), Leu-13C6,15N (an enriched stable isotope version of Leucine), and other similar amino acids and imino acids (e.g., 4-hydroxyproline). Arrangements of polypeptide sequence notations used herein have a left-side end corresponding to the amino terminal and a right-side end corresponding to the carboxy-terminal end, in accordance with IPTS / 128722251.1 Page 77 of 337Docket No.: AKT-031WO standard usage and convention. In some embodiments, a miniprotein disclosed herein has one or more of the following unconventional amino acids: trimethyllysine, dimethyllysine, monomethyllysine, isopropyl-lysine, Lys(Ac), norleucine, citrulline, L-citrulline, symmetrically dimethylated arginine (sRme2, Rme2s, or SDMA), nitroarginine (Arg(NO2)), 5 or Leu-13C6,15N.

[0347] In some embodiments, a miniprotein as provided herein is specific for a polypeptide or portion thereof having an amino acid sequence or portion or functional variant thereof as set forth in TABLE 1A. TABLE 1A: Exemplary Target Protein Amino Acid Sequences0

[0348] Certain Nectin-4 binding miniproteins are known in the art. See, e.g., SEQ ID NO: 1 and SEQ ID NO: 2, as set forth below. Molecular weights (calculated and observed) are also provided herein.IPTS / 128722251.1 Page 78 of 337Docket No.: AKT-031WO

[0349] The present disclosure recognizes that a source of a problem in therapeutics binding Nectin-4 is lack of sufficient specificity and affinity. Thus, provided herein are miniproteins that bind strongly, efficiently, and specifically to Nectin-4 (e.g., on a cell, e.g., on a cancer cell). 5

[0350] Another source of a problem includes toxicity (e.g., renal toxicity). In some embodiments, specificity and strength of binding for Nectin-4 in cancer cells reduces uptake into kidney.

[0351] In some embodiments, a miniprotein comprises or consists of a specific amino acid sequence. In some embodiments, a miniprotein has an amino acid sequence that is 70%,0 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to the amino acid sequence set forth in any of SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246 and 248.

[0352] In some embodiments, a miniprotein has an amino acid sequence that is 70%,5 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to at least 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44 or 45 amino acids of any one of SEQ ID NOs3-158, 161-168, 170-208, 212-237, 243-246 and 248. In some embodiments, a miniprotein has an amino acid sequence that is 70%, 75%,0 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to at least 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, or 45 contiguous amino acids of any one of SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-5 246 and 248. In some embodiments, a miniprotein comprises or consists of a specific amino acid sequence. In some embodiments, a miniprotein has an amino acid sequence that is 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to the amino acid sequence set forth in any of SEQ ID NOs: 170-0 176, 216-237, or 243-246. IPTS / 128722251.1 Page 79 of 337Docket No.: AKT-031WO

[0353] In some embodiments, a miniprotein has an amino acid sequence that is 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to at least 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 5 or 45 amino acids of any one of SEQ ID NOs: 170-176, 216-237, or 243-246.

[0354] In some embodiments, a miniprotein has an amino acid sequence that is 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,0 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, or 45 contiguous amino acids of any one of SEQ ID NOs: 170-176, 216-237 or 243-246.

[0355] In some embodiments, a miniprotein comprises or consists of a specific amino acid sequence. In some embodiments, a miniprotein has an amino acid sequence that is 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%,5 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to an amino acid sequence set forth in any of TABLES 1B, 1C, 1D, and / or 2A.

[0356] In some embodiments, a miniprotein has an amino acid sequence that is 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%,0 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to at least 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, or 45 amino acids of any one of the amino acid sequences set forth in any of TABLES 1B, 1C, 1D, and / or 2A.

[0357] In some embodiments, a miniprotein has an amino acid sequence that is 70%,5 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100% identical to at least 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, or 45 contiguous amino acids of any one of the amino acid sequences set forth in any of TABLES0 1B, 1C, 1D, and / or 2A.

[0358] As used herein and known to those of skill in the art, the twenty conventional amino acids and their abbreviations follow conventional usage. See Immunology-A Synthesis (Golub and Gren eds., Sinauer Associates, Sunderland, Mass., 2nd ed.1991), which is incorporated herein by reference. In some embodiments, an amino acid of the IPTS / 128722251.1 Page 80 of 337Docket No.: AKT-031WO present disclosure may be a stereoisomer (e.g., D-amino acids) of the twenty conventional amino acids. In some embodiments, an amino acid in a polypeptide of the present disclosure may be a non-natural amino acid. For example, amino acids such as Į-, Į-disubstituted amino acids, N-alkyl amino acids, and other unconventional amino acids may also be suitable 5 components for polypeptides of the present disclosure. Examples of unconventional amino acids include: 4-hydroxyproline, Ȗ-carboxyglutamate, İ-N,N,N-trimethyllysine, İ-N- acetyllysine, O-phosphoserine, N-acetylserine, N-formylmethionine, 3-methylhistidine, 5- hydroxylysine, N-methylarginine, and other similar amino acids and imino acids (e.g., 4- hydroxyproline). Arrangements of polypeptide sequence notations used herein have a left-0 side end corresponding to the amino terminal and a right-side end corresponding to the carboxy-terminal end, in accordance with standard usage and convention.

[0359] In some embodiments, a miniprotein provided by the present disclosure is set forth in one or more consensus sequences provided in TABLE 1B.

[0360] In some embodiments, a miniprotein with a sequence set forth in TABLE 1B has5 amino acid substitutions as provided in TABLE 1C. IPTS / 128722251.1 Page 81 of 337Docket No.: AKT-031WO e -hX NT.,rD I I X 2 2 X 4pi 7 D D C X X C 242XASA2XXI2X2XQFQFebo osoirn1iX7G17X1IXDCGICIIDXIXIQIQICIYYA4IY6262 mu diMncad pnala5GD D G Y Y Y Y D C 2 1 X X, no4-1X5G5G5GGAGG5ECYCECYCGGIDX 2 A A a on diisniL1 1 1 5 5 1 I I I I 5 GIYXCQIQIybimcaiv .oset 3XLXLXL1X1XXLDGDGDGDG1XG5E I Y Y deao rsce1X3 3 3 L L 3 G G G G L 1CIDGECEC wl21X1X1X31311X5151515131X D G I Ioalln niipomamporuN y1 2 2 2 X X 2 X X X X XL3GG51DGDGofmrehtr 8f pllrXaL1X1X1X21211XL3L3L3L 2 1 R X G G si t- 2de alp1e0 L L L X X L 1 1 1311XX2LRL3RLRL XCetharofmc1enX0T10X10X1L L 0 X X X X L 1 2 1 R R hX01011XKLKLKLKL01XL1XXA2121ceahttst dapuytexeuF T T T X X T A A A A X E L L X X e,iEqFf eS6FXFF6FF6FT6FTFFFFFT6FTFFTFFTFFTFFTFFA A L L nFTFTFATATo5di4i nr ctaee itbneadn onsasto s 5susXX45XX5XX56XX65XX556XX65X6 6 6 6 F F F F ci5X5X5X5X56X6XFQFElai h ipecmannoiecnneXesY4X4X4 X X 4 X X X X X X E E E E pa neel iteacnunqo 2X5YEYXDYDEYDDYXEYDEYDEYDEYD D K D D D D tEYEYDYEYEYDYEYEnueqbeacierstu lp ee CC 4 C C C C C C C C C C C C C C C C serratitspaferSpe lu b tnyshcius es butsanlf toraaser deptaeusm s pnroo I AI -II BI -II CI -II DI -II EI -II FI -II GI -II HI -II I -I JI -I KI -I LI -I MI -I NI -I OI -I PeI -c aiIIn f8ere o2ht oprdX,niocCF I I I I I I I I I I u:qiec d nsa i iBocm aet si 1 OsNusnshED ni oemn ys cai gihLIsnlm aa niwdrefBQ A6 7 8 9 0 1 2 3 4ocni n boES12121212222225 6 7 8 9 0 1 2222222222222222323232 nI mrocmhcT 1etesunaeIPTS / 128722251.1 Page 82 of 337Docket No.: AKT-031WO TABLE 1C: Consensus Sequences Substitutions"Kme3" refers to trimethyllysine, “sRme2” refers to symmetrically dimethylated arginine, “Cit” refers to citrulline, “Arg(NO2)” refers to nitroarginine, “Norleu” refers to Norleucine, “OH-Norleu” refers to OH-Norleucine. IPTS / 128722251.1 Page 83 of 337Docket No.: AKT-031WO s; L siA i ,2ro,s3itn e;E;E1r4oK,roceIY4 F Q1XC36 CeF 2 LN2 G m6 X AyX L K2 K PralCpI1D4KX Q LQK I Y7XDIQ Y QYI 1 Fm1 LY 2 6e X I1 1 X 2x G E2 2 C XE R EX X I Af LC C D Qos 3I I I 7 Ie 1CLD75D71X54YQ cX22 1 4 1 5 G X Cn13XXGXCXG4 R C Ieu X P R G RXCLRGLDG qL003LRL L G 2 1 Ge1 X A14RAL11 4 RSx 9 LX X LsX L 4 L D Ru9sS X2FXA8TDFLA X A L AITFDLT I LneF 2 F E F IFFEEATsUS6 X 6 E 6 E 6 I F SnNXEF6X I X E X C F CoED 2EDCLE I E L E GCSY X Y 2DYC D 2 E L:N2 5 2 3 2L2Y23 D NDO 1 CXC2XXCXPXC3XXXCPYLEDCLIEL B Q:O67071 2 3AETSDIN1 1717171 IPTS / 128722251.1 Page 84 of 337Docket No.: AKT-031WOs i,X,K;,3, 6 opi; K , or ;ecil or3K ;K,Q eQ rmK 1K ,X ,r K N r r )pnTo,ro ,Eo cAyx isemidy3 , o ) ; , e o , yhSX N ro,E,,, (oAtiK ,SR mK,T , Q Krl pdl oot N O; s p C r , A ,K,,yy nI)hhtisrTci ,Ds a s ( o , S , ) , K KoemefUA(1i D i4 , 6 , 2,R,NY ,,2)e,m2cOAG( ,,taE,Nsirm d erTIK X E X S 1 E c K N K Defotot”ITSr ; s ; ,X si,),A(,R s s e srsN Bo E i K D ; t K K 3 ,,K,Ai i rer“US,Ero2Xro,N 3 i e t 6 1”fECL1XC(,D,KmKiC,Ysi3X4XPeyrefe;rN h” 5“e ” 11;mp ,X3ea 6631X niK n“D“ C3X2 i ;e;e1- 53Xgranilniue1 1- l s LX43o urytL1XX0 mo ic-ot Lsr331X h9o ot -l eftyeX 2 srpr21XsrX8254e eff oerrp ”o N 1 1XFXCer””t sii-CL X 06 Gİ“;12RCX2 h“ N eX54X“ ;eotni9X2 1 ;dnFX744Xic isnr niegrX2X0ai4cigfer aS 6XIYX9t rra ol”r rtiUS 5X1 3 ap yhpi noN E42 XsSXX3CIIE a-teK“ t6D mi;reefNX2813 o etd ni rO CXCXX7ICs criersfty ”eell)2rmyhO tNQ:E”me (O6ySDIN42 Ddsmgr“otir tA“IPTS / 128722251.1 Page 86 of 337Docket No.: AKT-031WO

[0361] In some embodiments, the present disclosure provides a miniprotein. In some embodiments, the miniprotein is or comprises a polypeptide, comprising: an amino acid sequence, wherein the amino acid sequence comprises Formula III: CX2YX4X5X6FFTX10LX12X13LX15GX17DICX21YIX24X25X26FX28X29X30X31X32X33CIX36EIX39X40 X41LGCX45 (SEQ ID NO: 216) wherein X45 is an optional amino acid or carboxy terminus comprising an -OH and wherein X2 is D or E; X4 is D or K, X5 is E or G; X6 is Q or E; X10 is A or E, X12 is A, K, E, or S; X13 is A, R, Q, K, S, or Cit; X15 is Y, R, or K, X17 is A, D, G, or S; X21 is D, Q, E, L, S, or Y; X24 is Q, L, K, or S; X25 is A, Q, E, K; X26 is A, Q, K, S, Y, T, D, R, (Kme3), (sRme2), Cit, Arg(NO2), OH-Norleu, or Norleu; X28 is A, N, Q, D, K, or S; X29 is N, T, or Y; X30 is L, Y, or V; X31 is P or E; X32 is A, D, Q, G, or K; X33 is D, Q, E, I, or L; X36 is Q, K or E; X39 is L or R; X40 is D, Q, or E; X41 is N, K or Q; and X45, when present as an amino acid is S.

[0362] In some embodiments, the amino acid sequence satisfies one or more of: wherein if X4 is K, then X26 is K and X15 is Y, wherein if X4 is D, then X26 is one of N, T, D, R, (Kme3), (sRme2), Cit, or Arg(NO2), or X26 is K, X10 is E, X36 is K, and X39 is R, or wherein if the amino acid is leucine, then leucine can be L-leucine.

[0363] In some embodiments, a polypeptide according to Formula III or any of Formula IIIA-IIIP further comprises one or more of a linker, chelator, and radionuclide. In some embodiments, the linker can be or comprise linker comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, lys(MPB)-PEG4, PEG36, an ester linker, an amide linker, a maleimide linker, a, a succinimidyl-4-(N- maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- (SEQ ID NO: 239) or (PEG)n, wherein n is from 1 to 10, (Gly)1-10 (SEQ ID NO: 240), or any fragment or combination via covalent bond thereof. In some embodiments, the chelator comprises or consists of DOTA, DOPA, Macropa, PSC, N-succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), N-succinimidyl 3-trimethylstannylbenzoate (MeSTB), and Crown. In some embodiments, the radionuclide is Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La- 132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

[0364] In some embodiments, when present, the linker is attached to the C-terminal end of the polypeptide. In some embodiments, when present, the chelator is attached to either the IPTS / 128722251.1 Page 87 of 337Docket No.: AKT-031WO polypeptide or the linker. In some embodiments, when present, the radionuclide is attached to the chelator. In some embodiments, the polypeptide comprises one or more additional N- terminal amino acids. In some embodiments, the one or more amino acids on the N-terminal and / or the C-terminal end of the polypeptide.

[0365] In some embodiments, a miniprotein comprising an amino acid sequence of any of SEQ ID NOs: 170-176, 216-237, or 243-246 and / or according to any of TABLES 1B, 1C, 1D, and / or 2A has at least one disulfide bridge.

[0366] In some embodiments, a miniprotein comprising an amino acid sequence of any of SEQ ID NOs: 170-176, 216-237, or 243-246 and / or according to any of TABLES 1B, 1C, 1D, and / or 2A has at least two disulfide bridges.

[0367] In some embodiments, the miniprotein has at least two disulfide bridges.

[0368] In some embodiments, disulfide bridges are formed between cysteines 1 and 34 and between cysteines 20 and 44. In some embodiments, a miniprotein comprising four cysteines has two disulfide bridges and Cys 1 is connected to Cys 34 and Cys 20 is connected to Cys 44. In some embodiments, a cysteine is at a position with reference to a reference sequence having a certain length (e.g., SEQ ID NO: 195 having 45 amino acids). For example, in some embodiments, the cysteine corresponding to position 1 connects with 20 and the 34 connects with 44, etc.as provided herein.

[0369] In some embodiments, the miniprotein has one or more additional amino acids inserted into amino acids within CDP loop regions (amino acids in loops of secondary structures between cysteines connected to one another, e.g., amino acids in structures formed between Cys 1 and Cys 34 and Cys 20 and Cys 44). As will be understood to those in the art, retention of conformation is key to binding affinity and behavior; accordingly, in some embodiments, any additions within CDP loop regions can be made in a way that preserves proper conformation and stability such that binding affinity is not reduced and / or conformation or stability is not impaired or destroyed.

[0370] In some embodiments, the polypeptide is a monomer. In some embodiments, the polypeptide is a dimer, trimer, or tetramer. In some embodiments, the polypeptide comprises an amino acid sequence with at least 80% sequence identity to that of SEQ ID NO: 78. In some embodiments, the polypeptide comprises an amino acid sequence with at least 80% sequence identity to that of any of SEQ ID NOs: 3-158 or 177-215. In some embodiments, the polypeptide comprises a consensus sequence according to any of Formulas IIIA-IIIP (SEQ ID NOs: 216-237) according to TABLE 1B, further comprising a substitution in accordance with those set forth in TABLE 1C. In some embodiments, the polypeptide has an IPTS / 128722251.1 Page 88 of 337Docket No.: AKT-031WO amino acid sequence that meets the definitions as set forth in TABLE 1D. In some embodiments, the polypeptide has an amino acid sequence that meets a definition of any one or more of SEQ ID NOs: 170-176, 216-237, or 243-246.

[0371] In some embodiments, a sequence comprising a variable position (e.g., as in TABLE 1B, can also include a substitution with any cognate amino acid. As used herein, a cognate amino acid is one with one or more similar characteristics to another amino acid, such as, for example, a similar charge (e.g., a negatively charged amino acid, in reference to charge at physiologic pH), or, in some embodiments, a set of substitutions (e.g., more than one amino acid) that creates a similar charge profile to the polypeptide as prior to the substitution or set of substitutions, etc. IPTS / 128722251.1 Page 89 of 337Docket No.: AKT-031WO )4 / d4e+MnKuKLRKKLRKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKspeoIYIp YYICYYICYYICYYICYYI I I I I I I I I I I I I I I I I I I I I I reCYYCYYCYYCYYCYYCYYCYYCYYCYYCYYCYY Y Y Y Y Y Y Y Y Y Y Yfyex roCYCYCYCYCYCYCYCYCYCYCYCYCr r ”d3eI I I I I I I I I I I I I I I I I I I d ym moDCGDGDGDGDGDGDGDI I I I I I I I InGDGDGDGDGDGDGDGDGDGDGD D D D D D D D D DahK )ot“G G G G G G G G G G G R R G G R G GGGTGTGTGGGGGGGGGGGGG.c sr;edR R R R R R R R R R R R R R R R R R tnnLaRLKRLRLRLRLR R R R R R R R R ReRLRLRLRLRLRLRLRLRLRLRLRLRL L L L L L L L L L,e”fiesysLKLKLKLKLKLKLKLKLKLKLKLKLKLKLHLKLHRLHRKRHRHRKRKRKRKRKKK3rlC”lyeG D G D G G GL L L L L L L L L L,Pyhtcn4AeFAFAFAFAFAFAGFAGFAGFAGFNGFAGFNGFAGFNGFNGFAGFAG G G G G G G G G G”FAFAFAFAFKFEFDFSFTFEF2h“emiecFu ne EFqu EQFFEFEQF F F F F F F F F F F F F F F F F F F F F F F F C“;FEEEEEEEEEEEEEEEEEEEEE E E E E E E E E E E E E E,e”ndi ot eq DYDDDYDDDYDYDYDYDYDYDYD D DEDEDEDEDEDEDEDEDEDEDEDEDEDED1CnigsrSe Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YSE“r efnCECECECECECECECECECECECECECECECECECECECECECECECECECECEC ,.ga.- erieo(m”o2et 3o O#.dnhem r QNpiE n mD 011121314u uot 15161718 9 0 1 2 3 o losK r“e ;nS I 34345 55 555 67 8 9 1 1 2 2 2 2 pcf eimo ” e niMc eacrn ” sylyraeiuRh lyha vqe“;ld dtepeiSf“icmi omt eah ct sexsEud44nti edn trreiiapfe.ni L L etLGEGE sL Lsiesar”A mrYTYalTyn2et iY PT-P- AAYTYLTYLTYLTYLTYLTYLTYLTYLTYLTYL L L L L L LTYTYTYTYTYTYTYT d cnn- eu eu Dom K -2H2HE E2toE CTPTE E E E E E E E E E E E E E E E E E oqets“E N N NCACH A NiBCAIF TO D DCACACACACACACACACACACACACACACACACACApms re ;eLoo fctsernilB d hr lA nuceaf” urtTop2e mom2EeD3Rd ic4“ ota345678901112131415 6 7 8 9 0 1 2 3 4 5 6 7 8 9C1C1C1C1C1C2C20C NC C C C C C C C C C C C2C2C2C2C2C2C2C2C3C IPTS / 128722251.1 Page 90 of 337Docket No.: AKT-031WO )4K LKLKLKLKLKLKLKLKLKLKLKLGpKLKLKLKLKLKLKLKLKLKLKLK K K K K K K K KG G G G G G G G G G G G a G G G G GL L L L L L L L LT T Q L T T T T T T TG G G D E K T L A G G G G G G4 F F F FT D T T T T T T A A T T T T T T L T L L T LeF F F FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF F F F F F F F Fce E E E E E E E E E E E E E E E KF F F F F F F F Fnu EDEDEDEDEKEEEDEDEE E Q E E E E E E E E E E E E E EDEDEDEDEDEDEDEDKDEDEDEDEDEDEDEDEDEDEDE E E E E EqY Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YD D D D D DeE E E E E E E E E E E EY Y Y Y Y Y Y Y Y Y Y Y Y YSC C C C C C C C C C C CECECECECECKCECECECECECECECECECECECECECECEC3O QNESDI42526272829203132333435363738393041424 5 534445464748494051525354582suG1Gni L L L L L L L L L L L L L L L L L L L E E L L L LrY Y Y Y Y Y Y Y Y Y Y Y Y P-P- L L L L L L L LmeTETETETETETY Y Y Y Y YETETETETETETETETETETETETETEATA Y Y Y Y Y Y Y Y Y Y Y YTTETETETETETET T T T T Tt- C C C C C C C C C C C CACACACACACACE E E E E EN A A A A A A A A A A A ACOO A D DCACACACACACACACACACACACA dnuop2e moma 132333435363738 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3C3C3C4C4C4C4C44 5 6 7 8 9 0 1 2 3C NC C C C C C C4C4C4C4C4C5C5C5C5C5C5C5C5C5C5C6C6C6C6C IPTS / 128722251.1 Page 91 of 337Docket No.: AKT-031WO )4RKRKRKRKRKRKRKRKRKRKRKRKRKRKRKRKRKRKRKRKyLcAyLcAyLLFyLL R C R C R R RL L L L L L L L L L L L L L L L L L L L LF K L K L K K KG G G G G G G G G G G G A A( L ( L ) L ) L ) L ) L L LL T T L L K T TA A G A A A A s A s A c A c A c A c G G G4 F F F F F F F FLFLFTFTFKFLFLFTFKFKFTFTFTFyLTFyLTFA(TFA(TFA T A A A AeF F F F F F F F F F F F F F F F F F F F F( F ( F F Fce E E E E E E K Q K Q K Q ED F D F s F s F s F s F F Fnu EDEDEDEDEDEDEDEDEDEDEDEDEEDEEDEEDEEDEEDEEDEEDEEDELDIEEELDIEEEyDLEEyLEEyLEEyLEEEEEE qY Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y) D ) D P D P D D DeE E E ECECECECECECEY Y Y E Y E Y c Y c Y V Y V Y Y YSC C C CECECECECECECECECECECECICECICECA(ECA(EC)cEC)cECECEC3O QNESDI5565758595061626364656667686960717278484373747475757 5 5 54G 4 4 EGs4 4 4 4 4 4PEG-P- E4A A P-uG Gni L L L L L L L L L L L L L L L L L L EPEG GEG GE- LP- EP- EP-GT TAE OOTmY Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y P - P - PDDO reT T T T T T T T T T T T T T T T T TATA A A-- - Dt--ECECECECECECECECECECECECECECECECECECTOETCT TCT TCT uEaLnIN A A A A A A A A A A A A A A A A A A DCO A DIFO DIFO DIF 15813t1andnuop2e moma 4 5 6 7N68 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 90 1 2 CC6C6C6C6C6C7C7C7C7C7C7C7C7C7C7C8C8C8C8C8C8C8C8C8C8C9C9C9C IPTS / 128722251.1 Page 92 of 337Docket No.: AKT-031WO )4K LKLKLKLKLKLKLKLKLK K K K K K K K K K K K K K K K K K K K K K A AG G A A A A G AL L L L L L L L L L L L L L L L L L L L L L L LA A T T T T AA A A A A A A A A A A A A A A A A A A A A A A A A4 F F F F FT T T T T T T T T T T T T T T T T T T T T T T T T TeF F FF F F F F F F F F F F F F F F F F F F F F F F F F F F Fcne E E EFEFEFEFEFQFQFQFQFEFEFEFEFEFEFEFEFQFQFQFQFEFEFEFEFEFEFEFEFEFE uEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDE E E E EqY Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YD D D D DeE E E E E E E E E E E E E E E E E E E E E E E EY Y Y Y Y Y YSC C C C C C C C C C C C C C C C C C C C C C C CECECECECECECECECEC3O QNESDI 5 584848484 5676767677777777787878787970808081818181828282828383844 44 4 4 GG G G G4 GGEE EPEPE E EP4 4 4 4 4 4 PP- -P-P- 4G4G G G G Gs- -uA A A A A-A GE4GE4 4 GE4 4 GE4 4 GE4 4 GE4 4 GnTi T T TATOTOOOOTOEPP-GAEPEPP-GAE EPP-GAE EPP-GAE EPP-GAE EPP-GAE EPmrDDD e-D- D- O DD- l t - -a -Guuy- AT -nly- ATP-nly- ATP-nly- ATP-nly- ATP-nly- ATP-nly- A C1Ea8La8L -tncIAtec TO ODi:to teTO Dito teTO DitteTO DitteTO DitteTO DitteTDI cO:DI cO: oA DI B cO: oA DI B cO: oA DI B cO: oA DI B cO N9636513131a5n22An iB An iBn i n i n i n iA D dnuop2e0 1*2 3 4 5*6 7 8 9*0 1 2* * *mm33 4 5 6 7 8 9 0 1 2 3 4 5oa949596979899901010101010101010101111111111111111111112121212 2 2C NC C C C C C C C C C C C C C C C C C C C C C C C C C C C C C1C1C1C IPTS / 128722251.1 Page 93 of 337Docket No.: AKT-031WO )4AA A A A AS S S SL L L L L LS S S S S S S S A A A A A A A A A A A A A A A A A A AA A A A AL L L L L L L L L L L L L L L L L L L L L L L L L L LT T T T TA A A A A A A A A A A A A A A A A A A A A A A A A A A A4 F F FT T T T T T T T T T T T T T T T T T T T T T T T T T T TeF FF F F F F F F F F F F F F F F F F F F F F F F F F F F F F Fce EF F F F F F F F F F F F F F F F F F F F F F F F F F F F F F FnE Q Q Q Q E E E E Q Q Q Q E E E E E E Q E E E E A Q E E E E E EuEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDGDEDEDEDEDEDEDEDEDEDEDEDE E GqY Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YD D DeE E E E E E E E E E E E E E E D E E E E E E E E E E E EY Y Y YSC C C C C C C C C C C C C C C C C C C C C C C C C C C CECECECECEC3O QNE 3 3 4 5 5 5 6 7 7 7 8 90 1 2 3 4 5 6 7 8SDI 8 8 8 8 8 8 8 8 8 8 8 89898091929394959697989990101010101010101014 G 4 4 4 4G G GsE4GE4 4 GE4 4E4 44 44 44 444 444 44 444 44 uPn-iG PAE E -G PAE E -G G PAE E -G G G G G G G G G G G G G G G G G G G GAE E E E E E E E E E E E E E E E E E E Emr TP P- TP P- TP P- TP P P P P P P P P P P P P P P P P P P PetO-n-Dil :t y AO-nily AO-nily AO-n- - - - - - - - - - - - - - - - - - -in n n n n n n n n n n n n n n n n n noteTD to teTD to teTD tiotiotiotioti i i i i i i i i i i i i i iotot t t t t t t t t t t t t tIicO:DIicO:DIicO:DIi i i io o o o o o o o o o o o o oNnBAnBAnBAnB B B BiBiBiBiBiBiBiBiBiBiBiBiBiBiBiBiBdnuop2e*6* * *m7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8oma 21212121313131313131313131314141414141414141414151515151515 5 5 5C NC C C C C C C C C C C C C C C C C C C C C C C C C C C C C1C1C1C1C IPTS / 128722251.1 Page 94 of 337Docket No.: AKT-031WO )4RARASAQA(ARAQFRARARARARAC Q ( ( R Q R ( ( R R R R R R R R R R R R RL L L L L L ) L L L L LA F A A A F A A A K K K K K K K K K K A K KA A A A A A e A A A A AL ) L L L ) L L L L L L L L L L L L L L L LT T T T T T n T T T T TA e A A A e A A A A A A A A A A A A A A A A4 F F F F F F i F F F FT n T T T n T T T T T T T T T T T T T T T TeF F F F F F c F F FF F i F F F i F F F F F F F F F F F F F F F Fc E E E E E E u E E EF F F c F F F c F F F F F F F F F F F F F F F Fneu EDEDEDEDEDEDelE E EEEEEEEueEEEEEEueEEEEEEEEEEEEEEEEEEQEQEQEQEEEEEEE qY Y Y Y Y YD D D D D D l D D D l D D D D D D D D D D D D D D D DeD D E E Er Y Y Y Y Y Y r Y Y Y r Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YSC C C C CEConECECECECECEConECECEConECECDCECECECECECECECECECECECDCDC3O QNE9001112 3 4 5 6 7 8 9 0 1 2 3 5 4 5 6 7 8 9 0 1 2 3 4 5 6 7SDI 1 1 1111111111111111121212121112121212121213131313131313931314GEs 4 G 4PG4 G 4 G 4 4 44 44 4 4 44 4 4 444 444 44 444 4 - A 44 uni EPEPEPEGPEGPEG G G G G G G G G G G G G G G G G G G G G GPEPEPE E E E E E E E E E E E E E E E E E E E TGEGEmr -en-t i-t n-ioi t n-ioi t n-ioi t n-ioi t n-ioi t n-Pioi t n-Pioi t n-Pioi t n-P P P P P P P P P P P P P P P P Pioi t n-ioi t n-ioi t n-ioi t n- - - - - - - - - - - - - -OP-P-ioi t nioi t nioi t nioi t nioi t nioi t nioi t ninininininininiDo-niniitoi toi toi tototototonItotoNB B B B B B B B B B B B B B B B B B B B B B BiBiBiBiBiBtaniBiBdnuop2e mm 9506162636465666768696071727374757677787970 1 2 3 4 5 6 7 8 9oa1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1818 8 8 8 8 8 8 8 8C NC C C C C C C C C C C C C C C C C C C C C C1C1C1C1C1C1C1C1C1C IPTS / 128722251.1 Page 95 of 337Docket No.: AKT-031WO )4L RLRLRLRLRLRLRLRLRLRLRLRLRLRL L L L L L L L L L L L I s ) L L L LK K K K K K K K K K K K K KRKR R R R R R R R R R R C y c R R R RL L L L L L L L L L L L L L LKLKLK K K K K K K K K L L A A A K KA A A A A A A A A A A A A A A A ALAL L L L L L L L ) L ( L L L LT T T T T T T T T T T T T T T T T TATATA A A A A A c A s A A A A4 F F F F F F F F F F F F F F F F F F F FT T T T T T A T y T T T TeF F F F F F F F F F F F F F F F F F F FFFF F F F F ( F L F F F Fce Q E E Q Q E Q Q E E E E E E E E Q Q Q Q QF F F F F s F D F F F Fnu EDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEDEEDEEEEEEEEEyLEELIQEQEEEQE qY Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YDYD D D D P D E D D D DeD D D D E E E E E E E E E E E E D D D D D EY Y Y Y V Y E Y Y Y YSC C C C C C C C C C C C C C C C C C C C C CECECECEC)cECICECECECEC3O QNE839304142434445464748494051525354555657585777777 8 5 3 6 68 9SDI 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 4 7 7 9 971714 GE44PG G -)E EBP4 s 4 niG4 G 4 G 4 G 4 G 4 G 4 G 4 G 4 G 44 4PG4 G 4 G 4 G 4 44 44 44 4G G-PA-GAM(EP44 uEPEPEPEPEPEPEPEPEPEPEPEPEGPEGPEGPEGPEGPEG G GPEPEPE L L EPEPT T syl-G GAE Emr -en- - - - - - - - - - - - - - - - - - -P-t iY Y- -O O- TP-P--t nioi t nioi t nioi t nioi t nioi t nioi t nioi t nioi t nininininininininininini T TAoi toi toi toi toi toi toi toi tototototoECECTAOTD-D-AOnInI TOniniOD-totoNB B B B B B B B B B B B B B B BiBiBiBiBiB A A D DtatnanDnIiBiBdnuop2e mm 091929394959697989990010203040507080900 1 2 3 4 5 6 7 8 9 0 1oa1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 212121 1 1 1 1 1 1 1 2 2C NC C C C C C C C C C C C C C C C C C C C C2C2C2C2C2C2C2C2C2C2C IPTS / 128722251.1 Page 96 of 337Docket No.: AKT-031WO )4R KRKRKRKRKRARARA(A(A( ( C Q ( R R R R R R R R R R R R R R R R R RL L L L L L L L L LA A A F A K K K K K K A A A A A A K K K A A AA A A A A A A A A AL L L ) L L L L L L L L L L L L L L L L L L LT T T T T T T T T TA A A e A A A A A A A A A A A A A A A A A A A4 F F F F F F F F FT T T n T T T T T T T T T T T T T T T T T T TeF F F F F F F FF F F F i F F F F F F F F F F F F F F F F F F Fc Q E E Q Q Q QF F F F F c F F F F F F F F F F F F F F F F F F Fneu EDEDEDE E E EQEQEQEQEQEQEueQEQEQEQEQEQEQEEEEEEEQEQEQEQEQEQEEEEEEE qY YD D D D D D D D D D l D D D D D D D D D D D D D D D D D D DeDY Y Y Y Y Y Y Y Y Y Y r Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YSCECDCECDCECECDCDCDCDCDCDConDCECECECDCDCDCECECECDCDCDCECECECECECEC3O QNE0SDI811821831841851861871881891801911921931951451451481381381319999949941941941341341351911651914 4 4 4 4 s 4 niG4 G 4 G 4 G 4 G 4 G 4 G 4 G 4 4GG4 G 4 G 4 G 4 G 4GEGPEP4GGEP4 G 4GGEGP4EP4 G 4 G 4 4 uE E E E E E E E E E E E EGE E - - E - E E -GE - E EGEGEmPr-P P P P P P P P P P P P P Pe n- - - - - - - - - - - - - -A A Pti-t nioi t nioi t nioi t niot nit nit nit nit nit nit nit nit nit AT T -A PTO22 OAT -P A P A P P P PTO2A-TAT - T -TOnitO2A-TA- -Tnit nitBioBioBioBioBio o o o o oB B B B B B BOD- H HD- OD- H OOD- oD- H OOo oNB Bi i i i i iDnIN NnIDnIN D DnIiBnIN D DiBiBdnuop2e mm 223242526272829203132333435363738393041424344454647484940 1 2 3oa2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 25 5 5 5C NC C C C C C C C C C C C C C C C C C C C C C C C C C C2C2C2C2C2C IPTS / 128722251.1 Page 97 of 337Docket No.: AKT-031WO )4A LKLKLKLK(LA(LA(LALA A A A A A A A K K K K K K K E K E A A A K K K KA A A A A A A AL L L L L L L L L L L L L L L L L L L L L L L L LT T T T T T T TATA A A A A A A A A A A A A A E E E A A A A A A A4 F F F F F F F FT T T T T T T T T T T T T T T T T T T T T T T TeF F F F F F F FF F F F F F F F F F F F F F F F F F F F F F F F Fce E Q Q Q Q Q QF F F F F F F F F F F F F F F F F F F F F F F F Fnu EDEDEDEDEDE EQEQEQEQEQEQEQEQEQEQEQEQEQEQEQEQEEEEEEEQEQEQEEEEEEEEE qY Y Y Y YD D D D D D D D D D D D D D D D D D D K D D D D D D D DeE D D DY Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y YSC C C CDCDCDCDCECECECECECECECECDCDCDCECECECECECECECECECECECECECEC3O QNE596979899 0 0 0 1 2 3 3 3 4 4 4 5 5 5 5 6 7 8 9 0 1 2 3 4SDI 1 1 1 191020202020202020202020251515102020202021212121212878787874 4 4 44 4 4 G 4 4 GG G G G G G GsEuP4 n -iG444 44 GEP44 44 GE4 P 4GEPEP4 G 444 44 444 44EPE E E-P-P-P- AEG G G Gm PE E E E EP-G G GAE E E EP-GAE EP- A - AEG G G G G G G G G GPE E E E E E E E E EATATATATr T -PeOn-Pn-Pn-Pn-n- ATP-P Pn-n-n- ATP-n- AT T -P P P P P P P P P PA-n-n-n- - - - - - -OOOO t-Di-tiotiotiotioto TO DitititTOitTOO DT2ititit nit nit nit nit nit nit nit DD- D- D- BBO- o o oOD: oOD: -Oo o o o o o o o o o -NnIiBiBiBi iDnIiBiBiB DnIiB DnInIH D NiBiBiBiBiBiBiBiBiBiBaL aGuCcA dnuop2e mm 45556575859506162636465666768696071727374757677787970818283 4 5 6oa2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 28 8 8 8C NC C C C C C C C C C C C C C C C C C C C C C C C C C C C2C2C2C2C2C IPTS / 128722251.1 Page 98 of 337Docket No.: AKT-031WO )4GuLeNLN5GLGLIECLGLGLLIIEIECLLALA)NN5GLGL.4add loD( 1 N N E G N N E E E A P P 5 1 K K 4LG , D D I P D D E I I P L L 1 , D D snu ar)l)olo cyIPE)6 L L C L L L I C C L Y Y , 6 L L yCba ascycy lgENCI53I1EI L Y I I C L L Y Q Q 6 C I IEEEA Q E E L A A Q F F C 3 E Eo t laa lglgenC1, - uICIPCLF)EIEIAPPLPLF))3)3311-EIEId rut desenen elL 6 e LY 3 C C L Y Y 3 e e - u C Ceta u e eyGP -C L GEGQ e L L Y Q Q e m m u e L L cn l lhtu3e1(NP PF)mKGPAPQFF)F)mKK(K( -eLL(KPKPen “ ebyht yhe(2FL- S(uDnRe)Noc nisn ec(4(-8-)KL 5 s)(Y1iu,dhc)-)iet tetaYNY5Q,F6CIYIYIYIDIYIYIYIYIYIDDGD N m,6I I 2s eleh ate ae ecC1I,SA31SCECQCGGSCQCQCQCQG 5 K C Y YCG G G 1 ( 3 Y Y y ba w,caca aaD6GCQG3I-YuIeDIDDI R I I I I IGRRLRL,6AQ1-CICICADGL)DDDGDGDGDGLRR)R)C3IYueDGDGdl nl nI-ar R1 aattar r ttee11et-et-t-0L-YCL(GRGRGRtiGRGRGRGRGR)e2erp1-QCL(GRGR4m1 001RuKeIDIELRLRLRC(LRLRLRLRLRmKmKiKueIDIELRL3s - m1,1, ,7,)loLLA(GGEIALALALALALALALALAL( ( ( L G E KRKy dlo or7,47,44, cy4TATR)C)ATATATATATA A A ALALALA(AGRICLALACo cf ed ,1,1 1- lgeFcFF N N F F F F FTFTFTFTFTFTFTFTF)N)NTFTFtne EFE5151FEFQFEFQFEFEFEFEFEFEFEFEFE5151FEFEd reaeh -sn-n niacacac eeneu EqDED,6,6EDEDEDEDEDEDEDEDEDE E E E , , E E tc A2ugeded dleYoySEYCECC3C13Y1EYCDYCEY Y Y Y Y YDYDYDYDY6C6CDYDYeCDCECECECECECECECECEC3131ECECnn Enoiodod dhotecLBtsiolol lc(43 s Ad cycy yc-eOiTdnctaca az aQNE5 4 5 0 2 3 4 5 6 7 8 8 1s nia,z zaSDI8712399191023961616161616161428484 yanaC,dnIaaraart ycnele-5twb 1er tteoa - et-t-o0ihthl s-10snIdn1, 01, os71,77, i4 ecda,netnaI4, ,-1 4,4,ni(-1 1((ec- -a s4 4GEen31a ah ersuGni EG4 4 4 4 4 4 4 4PEG P: u-P- EGPEGPEGPEGPEG G GPEPEPEP A qegiTs se1fhphlplplaoulrdoa a:Fme A A-n-n-n- - - - -Olln:4:821::t2T222 2T iti inininininiotototototototoD: asdoitGGG44-H O H H H H O N N D N N N N DiBiBiBiBiBiBiBiBuE nI:nuan EPEGGPEPE EdE onTpiumb - - -P-P-mATATAoOooTni IC p2eN#C* caOOOtoD D DiTImm 788898091 2 3 8 9 0 1 2 3 4 5 6 7B Foa2 2 2 2929292929203030 0 0 0 0 0C NC C C C C C C C C C C3C3C3C3C3C3C IPTS / 128722251.1 Page 99 of 337Docket No.: AKT-031WO TABLE 2B. Binding Affinities of Exemplary Compounds to Nectin-4IPTS / 128722251.1 Page 100 of 337Docket No.: AKT-031WOIPTS / 128722251.1 Page 101 of 337Docket No.: AKT-031WOIPTS / 128722251.1 Page 102 of 337Docket No.: AKT-031WO 5 0 5 0 50

[0372] In some embodiments, a miniprotein of the present disclosure exhibits binding specificity to human Nectin-4. For example, in some embodiments a miniprotein provided by the present disclosure, such as, for example, those represented by any one of SEQ ID NOs: 3- 158, 161-168, 170-208, 212-237, 243-246 and 248, demonstrates binding when expressed on the surface of yeast and binding to Nectin-4 tested by flow cytometry. In some embodiments, IPTS / 128722251.1 Page 103 of 337Docket No.: AKT-031WO a miniprotein provided by the present disclosure, such as, for example, those represented by any one of SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246 and 248or in accordance with TABLES 1B, 1C, 1D, and / or 2A, demonstrates binding specificity via flow cytometry when, for example, such a Nectin-4 miniprotein (e.g., as represented by any of 5 SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246 and 248 or in accordance with any of TABLES 1B, 1C, 1D and / or 2A) only binds to Nectin-4 and not to other antigens.

[0373] In some embodiments, a miniprotein of the present disclosure such as, for example, any of those represented by SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246 and 248 or in accordance with TABLES 1B, 1C, 1D, 2A, 2B, and / or 2C shows greater than 100 nM potency. In some embodiments, a miniprotein shows potency greater than 1, 2, 3, 4, 5, 6, 7, 8, 9 nM or more.

[0374] In some embodiments, a miniprotein is part of a conjugate comprising one or more modifications or components, for example, as provided herein (see, e.g., TABLE 2A).

[0375] In some embodiments, a miniprotein provided by the present disclosure is set forth5 in the consensus sequences provided as Formula IV: CX2X3X4X5X6X7X8X9X10X11X12X13X14X15X16X17X18X19CX21X22X23X24X25X26X27X28X29X 30X31X32X33CX35X36X37X38X39X40X41X42X43CS (SEQ ID NO: 233) wherein X2 is E, G, A, S, T, D, N, K, R, Y, F, V, I, or W; X3 is Y, P, G, A, S, T, Q, K, H, F, W,0 V, M, D, E, L, or I; X4 is D, S, N, R, Y, L, M, G, T, or I; X5 is E, G, D, Q, F, W, V, L, I, M, K, or R; X6 is E, P, G, D, Q, N, K, Y, F, W, or V; X7 is F, Y, or W; X8 is F, Y, W, I, or M; X9 is T, P, A, S, D, Q, N, K, Y, F, V, M, E, R, or L; X10 is A, S, E, N, K, F, W, V, L, I, G, T, D, Q, R, or H; X11 is L, T, I, or M; X12 is K, L, G, A, S, T, N, R, H, F, W, V, I, or M; X13 is R, G, A, S, E, N, K, Y, W, L, I, or M; X14 is L, T, V, I, or M; X15 is R,5 T, Q, K, L, I, M, or V; X16 is G, D, N, K, R, H, Y, W, V, L, I, or M; X17 is G, P, A, S, T, D, Q, N, R, H, Y, F, W, V, L, or M; X18 is D, P, G, A, T, E, Q, N, K, Y, F, W, V, I, M, or S; X19 is I, P, A, T, D, N, Y, V, M, G, or Q; X21 is Y, S, T, D, E, K, F, W, L, I, or V; X22 is Y or E; X23 is I, A, T, Y, V, L, M, or F; X24 is Q, P, G, D, K, R, H, F, V, L, I, M, or N; X25 is A, P, S, D, E, Q, K, R, H, Y, F, W, V, I, M, or T; X26 is S, P, G, A, D, Q, N,0 R, F, V, L, I, T, E, or W; X27 is F, P, A, S, K, H, Y, W, M, E, or V; X28 is Q, P, G, A, S, D, E, K, R, H, Y, W, V, L, F, or I; X29 is Y, P, A, S, E, Q, N, K, F, W, L, I, M, T, or V; X30 is L, P, G, A, S, T, E, N, R, H, F, W, V, I, M, Q, or K; X31 is P, G, A, T, D, E, Q, N, K, R, H, Y, V, S, W, L, or I; X32 is G, A, S, D, N, R, H, Y, L, I, or V; X33 is L, P, G, A, S, D, E, N, K, R, H, Y, F, W, V, I, or M; X35 is I, P, S, D, E, N, K, R, Y, F, W, L, or M; IPTS / 128722251.1 Page 104 of 337Docket No.: AKT-031WO X36 is E, G, A, S, T, D, Q, K, R, H, Y, W, L, I, or M; X37 is E, P, G, A, S, T, N, K, R, H, Y, F, W, V, or D; X38 is I, A, S, E, Y, F, W, V, L, T, or H; X39 is L, S, T, E, N, R, H, Y, F, W, V, M, D, or I; X40 is D, G, A, S, E, Q, R, H, F, W, V, L, I, M, N, or K; X41 is N, G, A, S, D, Q, R, H, Y, F, V, L, I, M, P, or K; X42 I, L, P, G, Q, N, H, F, W, I, M, or S; 5 and X43 is G, P, A, T, D, N, K, R, Y, F, W, V, I, or Q.

[0376] In some embodiments, the consensus sequence of Formula IV is summarized in TABLE 2C. In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula IV, wherein X2-X43 comprise amino acid residues of SEQ ID NO: 78 or any one of the amino acids of the allowed substitutions in0 TABLE 2C, and / or any one of the preferred substitutions in TABLE 2C. In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula IV, wherein X2-X43 comprise amino acid residues of SEQ ID NO: 78 and / or any one of the preferred substitutions in TABLE 2C. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 785 comprising a single allowed substitution shown in TABLE 2C. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 78 comprising a single preferred substitution shown in TABLE 2C. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 78 comprising 2 or more allowed substitution shown in TABLE 2C. In some embodiments, a miniprotein provided by the0 present disclosure comprises SEQ ID NO: 78 comprising 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, 12 or more, 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or more, 20 or more, 21 or more, 22 or more, 23 or more, 24 or more, 25 or more, 26 or more, 27 or more, 28 or more, 29 or more, 30 or more, 31 or more, 32 or more, 33 or more, 34 or more, 35 or more, 36 or more,5 37 or more, 38 or more, 39 or more, 40 or more, 41 or more, or 42 or more allowed substitution shown in TABLE 2C. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 78 comprising a single preferred substitution shown in TABLE 2C. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 78 comprising two preferred substitutions, three preferred0 substitutions, four preferred substitutions, or five preferred substitutions shown in TABLE 2C. IPTS / 128722251.1 Page 105 of 337Docket No.: AKT-031WO TABLE 2C. Formula IV Consensus and SubstitutionsIPTS / 128722251.1 Page 106 of 337Docket No.: AKT-031WO

[0376] In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula V: CX2X3X4X5X6X7X8X9X10X11X12X13X14X15X16X17X18X19CX21X22X23X24X25X26X27X28X29X 5 30X31X32X33CX35X36X37X38X39X40X41X42X43CS (SEQ ID NO: 234) wherein X2 is E, P, G, A, S, T, Q, N, K, R, H, Y, F, W, V, L, I, or M; X3 is Y, P, G, A, S, T, D, E, Q, N, K, R, H, F, W, V, L, I, or M; X4 is D, P, G, A, S, T, E, Q, N, K, R, H, Y, F, W, V, L, I, or M; X5 is E, P, G, S, T, D, Q, N, K, R, H, F, W, V, L, I, M, or Y; X6 is E, P, G, A, S, T, D, Q, N, K, R, H, F, W, V, L, I, M, or Y; X7 is F, Y, or W; X8 is F, T, Y, IPTS / 128722251.1 Page 107 of 337Docket No.: AKT-031WO W, V, L, I, or M; X9 is T, P, G, S, D, E, N, K, R, H, Y, F, V, L, I, M, A, Q, or W; X10 is A, P, G, S, T, D, E, Q, N, K, R, H, Y, F, W, V, L, I, or M; X11 is L, A, V, I, or M; X12 is A, G, S, D, E, Q, N, K, R, H, Y, F, W, V, L, I, M, or T; X13 is R, P, S, T, D, E, Q, K, H, Y, F, V, L, M, G, A, N, W, or I; X14 is L, A, T, F, V, I, or M; X15 is R, Q, Y, F, W, V, L, 5 I, M, or K; X16 is G, P, A, S, T, D, E, Q, N, K, R, H, Y, F, W, V, L, M, or I; X17 is G, P, A, S, T, D, E, Q, N, K, R, H, Y, W, V, L, I, M, or F; X18 is D, P, G, A, S, T, E, Q, N, K, R, H, Y, W, V, I, M, F, or L; X19 is I, P, G, A, S, T, D, E, Q, N, K, R, Y, F, W, V, L, M, or H; X21 is Y, P, G, A, S, T, D, E, Q, N, K, R, H, F, W, V, L, I, or M; X22 is Y, H, or F; X23 is I, G, A, S, T, Y, W, V, L, M, or F; X24 is Q, G, S, T, D, E, N, K, R, H, F, W, V,0 L, I, M, P, A, or Y; X25 is A, G, S, T, D, E, Q, N, K, R, H, Y, F, W, V, M, P, L, or I; X26 is K, P, G, A, S, T, D, E, Q, N, R, H, Y, F, W, V, L, I, or M; X27 is F, P, G, A, S, T, D, E, Q, N, K, R, H, Y, W, V, L, I, or M; X28 is Q, P, G, A, S, T, D, E, N, K, R, H, Y, F, W, V, L, I, or M; X29 is Y, P, G, A, S, T, D, E, N, K, R, H, F, W, V, L, I, M, or Q; X30 is L, P, G, A, S, T, D, E, Q, N, K, R, H, Y, F, W, V, I, or M; X31 is P, G, A, S, T, D, Q, N,5 K, R, H, Y, F, V, I, M, E, W, or L; X32 is G, P, A, S, T, D, E, Q, N, K, R, H, Y, F, W, V, L, I, or M; X33 is L, P, G, A, S, T, D, E, Q, N, K, R, H, Y, F, W, V, I, or M; X35 is I, P, G, A, S, T, D, E, Q, N, K, R, Y, F, W, V, L, M, or H; X36 is E, P, G, A, S, D, Q, N, R, H, F, V, L, I, M, T, K, Y, or W; X37 is E, P, G, A, S, T, D, N, K, H, Y, F, W, V, L, I, M, Q, or R; X38 is I, P, G, A, S, T, E, Q, N, K, H, Y, F, W, V, L, or M; X39 is L, G, A, S, T, D,0 E, Q, N, K, R, H, Y, W, V, I, M, or F; X40 is D, P, G, A, S, E, Q, N, K, R, H, Y, F, W, V, L, I, M, or T; X41 is N, P, G, A, S, T, D, E, Q, K, R, H, Y, F, W, V, L, I, or M; X42 is L, G, A, S, T, E, Q, N, K, R, H, Y, F, W, V, I, or M; and X43 is G, P, A, S, T, D, E, Q, N, K, R, H, Y, F, W, V, L, M, or I.

[0377] In some embodiments, the consensus sequence of Formula V is summarized in5 TABLE 2D. In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula V, wherein X2-X43 comprise amino acid residues of SEQ ID NO: 83, any one of the amino acids of the allowed substitutions in TABLE 2D, and / or any one of the preferred substitutions in TABLE 2D. In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus0 sequences provided as Formula V, wherein X2-X43 comprise amino acid residues of SEQ ID NO: 83 or any one of the preferred substitutions in TABLE 2D. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 83 comprising a single allowed substitution shown in TABLE 2D. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 83 comprising a single preferred IPTS / 128722251.1 Page 108 of 337Docket No.: AKT-031WO substitution shown in TABLE 2D. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 83 comprising 2 or more allowed substitution shown in TABLE 2D. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 83 comprising 3 or more, 4 or more, 5 or more, 6 or more, 5 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, 12 or more, 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or more, 20 or more, 21 or more, 22 or more, 23 or more, 24 or more, 25 or more, 26 or more, 27 or more, 28 or more, 29 or more, 30 or more, 31 or more, 32 or more, 33 or more, 34 or more, 35 or more, 36 or more, 37 or more, 38 or more, 39 or more, 40 or more, 41 or more, or 42 or more allowed substitution0 shown in TABLE 2D. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 83 comprising a single preferred substitution shown in TABLE 2D. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 83 comprising two preferred substitutions, three preferred substitutions, four preferred substitutions, or five preferred substitutions shown in TABLE5 2D. TABLE 2D. Formula V Consensus and SubstitutionsIPTS / 128722251.1 Page 109 of 337Docket No.: AKT-031WOIPTS / 128722251.1 Page 110 of 337Docket No.: AKT-031WO

[0377] In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula VI: CX2X3X4X5X6X7X8X9X10X11X12X13X14X15X16X17X18X19CX21X22X23X24X25X26X27X28X29X 5 30X31X32X33CX35X36X37X38X39X40X41X42X43CS (SEQ ID NO: 235) wherein X2 is E, P, G, A, S, T, D, Q, N, K, R, H, Y, W, V, L, I, M, or F; X3 is Y, P, G, A, S, T, D, E, Q, K, R, H, F, W, V, L, I, M, or N; X4 is D, P, A, S, E, Q, N, or H; X5 is E, P, G, A, T, Q, N, K, R, H, Y, F, W, V, L, I, M, S, or D; X6 is Q, P, G, A, S, T, D, E, N, K, R, H, Y, F, W, V, L, I, or M; X7 is F, Y, or W; X8 is F, Y, W, V, I, or M; X9 is T, P,0 G, A, S, D, Q, N, R, H, Y, F, V, L, I, M, E, K, or W; X10 is A, G, T, D, E, Q, N, K, R, H, W, L, I, M, S, Y, F, or V; X11 is L, V, I, or M; X12 is A, G, S, T, D, K, R, Y, F, W, V, L, I, M, E, Q, N, or H; X13 is R, G, A, S, T, D, Q, N, K, H, Y, F, W, V, L, M, E, or I; X14 is L, T, V, I, or M; X15 is R, Q, K, I, or M; X16 is G, A, T, D, E, Q, N, K, R, H, Y, W, V, L, I, M, P, S, or F; X17 is G, P, A, S, T, D, E, Q, N, K, R, H, Y, F, W, V, L, I, or M; X18 IPTS / 128722251.1 Page 111 of 337Docket No.: AKT-031WO is D, P, G, A, S, T, E, N, K, H, Y, F, L, M, Q, or K; X19 is I, G, A, S, T, E, Q, N, K, R, H, Y, F, W, V, L, or M; X21 is Y, P, G, A, S, D, E, Q, N, K, R, H, F, W, V, L, I, M, or T; X22 is Y; X23 is I, A, T, Y, F, W, V, L, or M; X24 is Q, P, A, S, D, E, N, K, H, Y, F, W, V, L, I, G, T, R, or M; X25 is E, P, G, A, S, T, D, Q, N, R, H, Y, F, W, V, L, I, M, or K; 5 X26 is Q, G, A, S, T, E, N, K, R, H, F, W, V, L, I, M, D, or Y; X27 is F, Y, W, L, I, M, or V; X28 is A, P, G, S, T, D, E, Q, N, K, R, H, Y, W, V, L, I, M, or F; X29 is T, P, G, A, S, D, E, Q, K, R, H, Y, F, W, V, L, I, M, or N; X30 is V, P, G, A, T, D, E, N, K, R, H, Y, F, W, I, M, S, Q, or L; X31 is P, G, A, S, T, D, E, Q, N, K, R, H, Y, F, W, V, L, I, or M; X32 is G, P, A, T, D, E, Q, N, K, R, H, Y, F, W, V, L, I, M, or S; X33 is L, P, G, A, S, T,0 D, E, Q, K, R, H, Y, F, W, V, I, M, or N; X35 is I, P, G, A, S, T, D, E, Q, N, K, R, H, Y, F, W, L, M, or V; X36 is E, P, G, A, S, T, D, N, R, H, F, W, V, L, I, M, K, or Y; X37 is E, P, G, A, S, T, D, N, R, H, Y, W, V, L, I, M, Q, K, or F; X38 is I, G, A, S, E, Q, H, Y, W, V, L, M, P, or F; X39 is L, G, A, S, T, D, E, Q, N, K, H, Y, F, W, V, I, M, or R; X40 is D, P, G, A, S, T, E, Q, N, R, H, Y, F, W, L, I, M, or K; X41 is Q, P, G, A, S, T, D, E,5 N, K, R, H, Y, F, W, V, L, I, or M; X42 is L, G, A, S, T, E, Q, R, H, Y, F, V, I, M, N, or W; and X43 is G, P, A, S, T, D, E, Q, N, K, F, W, V, L, I, M, R, H, or Y.

[0378] In some embodiments, the consensus sequence of Formula VI is summarized in TABLE 2E. In some embodiments, a miniprotein provided by the present disclosure is set0 forth in the consensus sequences provided as Formula VI, wherein X2-X43 comprise amino acid residues of SEQ ID NO: 85, any one of the amino acids of the allowed substitutions in TABLE 2E, and / or any one of the preferred substitutions in TABLE 2E. In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula VI, wherein X2-X43 comprise amino acid residues of SEQ5 ID NO: 85 and / or any one of the preferred substitutions in TABLE 2E. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 85 comprising a single allowed substitution shown in TABLE 2E. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 85 comprising a single preferred substitution shown in TABLE 2E. In some embodiments, a miniprotein0 provided by the present disclosure comprises SEQ ID NO: 85 comprising 2 or more allowed substitution shown in TABLE 2E. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 85 comprising 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, 12 or more, 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or more, 20 or more, 21 or IPTS / 128722251.1 Page 112 of 337Docket No.: AKT-031WO more, 22 or more, 23 or more, 24 or more, 25 or more, 26 or more, 27 or more, 28 or more, 29 or more, 30 or more, 31 or more, 32 or more, 33 or more, 34 or more, 35 or more, 36 or more, 37 or more, 38 or more, 39 or more, 40 or more, 41 or more, or 42 or more allowed substitution shown in TABLE 2E. In some embodiments, a miniprotein provided by the 5 present disclosure comprises SEQ ID NO: 85 comprising a single preferred substitution shown in TABLE 2E. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 85 comprising two preferred substitutions, three preferred substitutions, four preferred substitutions, or five preferred substitutions shown in TABLE 2E. 0 TABLE 2E. Formula VI Consensus and SubstitutionsIPTS / 128722251.1 Page 113 of 337Docket No.: AKT-031WOIPTS / 128722251.1 Page 114 of 337Docket No.: AKT-031WO

[0379] In some embodiments, the consensus sequence of Formula VII is summarized in TABLE 2F. In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula VII, wherein X2-X43 comprise amino 5 acid residues of SEQ ID NO: 195, any one of the amino acids of the allowed substitutions in TABLE 2F, and / or any one of the preferred substitutions in TABLE 2F. In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula VII, wherein X2-X43comprise amino acid residues of SEQ ID NO: 195 and / or any one of the preferred substitutions in TABLE 2F. In some 0 embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 195 comprising a single allowed substitution shown in TABLE 2F. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 195 comprising a single preferred substitution shown in TABLE 2F. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 195 comprising 2 or more allowed5 substitution shown in TABLE 2F. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 195 comprising 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, 12 or more, 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or more, 20 or more, 21 or more, 22 or more, 23 or more, 24 or more, 25 or more, 26 or more, 27 or more, 28 or more,0 29 or more, 30 or more, 31 or more, 32 or more, 33 or more, 34 or more, 35 or more, 36 or more, 37 or more, 38 or more, 39 or more, 40 or more, 41 or more, or 42 or more allowed substitution shown in TABLE 2F. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 195 comprising a single preferred substitution shown in TABLE 2F. In some embodiments, a miniprotein provided by the present IPTS / 128722251.1 Page 115 of 337Docket No.: AKT-031WO disclosure comprises SEQ ID NO: 195 comprising two preferred substitutions, three preferred substitutions, four preferred substitutions, or five preferred substitutions shown in TABLE 2F. TABLE 2F. Formula VII Consensus and SubstitutionsIPTS / 128722251.1 Page 116 of 337Docket No.: AKT-031WOIPTS / 128722251.1 Page 117 of 337Docket No.: AKT-031WO

[0380] In some embodiments, the consensus sequence of Formula VIII is summarized in TABLE 2G. Here, TABLE 2G differs from TABLE 2F in that the substitutable amino acid at position X24 of Formula VIII in TABLE 2G is a trimethyllysine (Kme3) whereas the substitutable amino acid at position X26 of Formula VII in TABLE 2F is a lysine (K). 5

[0381] In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus sequences provided as Formula VIII, wherein X2-X43 comprise amino acid residues of SEQ ID NO: 103, any one of the amino acids of the allowed substitutions in TABLE 2G, and / or any one of the preferred substitutions in TABLE 2G. In some embodiments, a miniprotein provided by the present disclosure is set forth in the consensus0 sequences provided as Formula VIII, wherein X2-X43 comprise amino acid residues of SEQ ID NO: 103 and / or any one of the preferred substitutions in TABLE 2G. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 103 comprising a single allowed substitution shown in TABLE 2G. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 103 comprising a5 single preferred substitution shown in TABLE 2G. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 103 comprising 2 or more allowed substitution shown in TABLE 2G. In some embodiments, a miniprotein provided by the present disclosure comprises SEQ ID NO: 103 comprising 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, 12 or more, 13 or more, 140 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or more, 20 or more, 21 or more, 22 or more, 23 or more, 24 or more, 25 or more, 26 or more, 27 or more, 28 or more, 29 or more, 30 or more, 31 or more, 32 or more, 33 or more, 34 or more, 35 or more, 36 or more, 37 or more, 38 or more, 39 or more, 40 or more, 41 or more, or 42 or more allowed substitution shown in TABLE 2G. In some embodiments, a miniprotein provided by the5 present disclosure comprises SEQ ID NO: 103 comprising a single preferred substitution shown in TABLE 2G. In some embodiments, a miniprotein provided by the present IPTS / 128722251.1 Page 118 of 337Docket No.: AKT-031WO disclosure comprises SEQ ID NO: 103 comprising two preferred substitutions, three preferred substitutions, four preferred substitutions, or five preferred substitutions shown in TABLE 2G. TABLE 2G. Formula VIII Consensus and SubstitutionsIPTS / 128722251.1 Page 119 of 337Docket No.: AKT-031WOIPTS / 128722251.1 Page 120 of 337Docket No.: AKT-031WO

[0382] In some embodiments, a miniprotein in accordance with the present disclosure displays a binding specificity to human Nectin-4. In some embodiments, the miniprotein comprises a binding affinity characterized by a dissociation constant ranging from about 500 nM to about 1 pM, e.g., 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5 5, 4, 3, 2, 1 nM, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 pM binding affinity to human Nectin-4. Without being bound by theory, the present disclosure contemplates that, in some embodiments, a preferred dissociation constant of a miniprotein is about 10 nM or less, about 7.5 nM, about 5 nM or less, about 2.5 nM or less, about 1 nM or less (i.e., in the picomolar range). For clarity, a stronger binder can be one that has a binding0 affinity of 2.5 nM as compared to one with 5 nM to Nectin 4, and a weaker binder one with a binding affinity of 5 nM to Nectin-4 as compared to a binder with a binding affinity of 2.5 nM to Nectin-4.

[0383] In some embodiments, a miniprotein of the present disclosure binds to Nectin-4 with a binding affinity of about 1 pM to 100 nM. 5

[0384] In some embodiments, a miniprotein in accordance with the present disclosure binds to Nectin-4 with a binding affinity of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 pM; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550,0 600, 650, 700, 750, 800, 850, 900, 950, or 1000 nM. In some embodiments, a miniprotein in accordance with the present disclosure binds to Nectin-4 with a binding affinity of about 1 pM to 100 pM, 10 pM to 1 nM, 100 pM to 10 nM, or 1 nM to 100 nM.

[0385] In some embodiments, the binding affinity (KDof Kd) of a polypeptide (or composition comprising such polypeptide, e.g., a miniprotein) as provided herein is in a5 range of about 1 pM to 100 nM. IPTS / 128722251.1 Page 121 of 337Docket No.: AKT-031WO

[0386] In some embodiments, a binding affinity is between about 1 pM to 100 nM, 1 pM to 100 pM, 10 pM to 1 nM, 100 pM to 10 nM, or 1 nM to 100 nM. In some embodiments, a binding affinity is between about 1 pM to 5 pM, 1 pM to 10 pM, 1 pM to 15 pM, 1 pM to 20 pM, 1 pM to 25 pM, 1 pM to 30 pM, 1 pM to 35 pM, 1 pM to 40 pM, 1 pM to 45 pM, 1 pM 5 to 50 pM, 1 pM to 55 pM, 1 pM to 60 pM, 1 pM to 65 pM, 1 pM to 70 pM, 1 pM to 75 pM, 1 pM to 80 pM, 1 pM to 85 pM, 1 pM to 90 pM, 1 pM to 95 pM, or 1 pM to 100 pM. In some embodiments, a binding affinity is between about 25 pM to 30 pM, 25 pM to 35 pM, 25 pM to 40 pM, 25 pM to 45 pM, 25 pM to 50 pM, 25 pM to 55 pM, 25 pM to 60 pM, 25 pM to 65 pM, 25 pM to 70 pM, 25 pM to 75 pM, 25 pM to 80 pM, 25 pM to 85 pM, 25 pM to 90 pM,0 25 pM to 95 pM, or 25 pM to 100 pM. In some embodiments, a binding affinity is between about 50 pM to 55 pM, 50 pM to 60 pM, 50 pM to 65 pM, 50 pM to 70 pM, 50 pM to 75 pM, 50 pM to 80 pM, 50 pM to 85 pM, 50 pM to 90 pM, 50 pM to 95 pM, or 50 pM to 100 pM. In some embodiments, a binding affinity is between about 75 pM to 80 pM, 75 pM to 85 pM, 75 pM to 90 pM, 75 pM to 95 pM, or 75 pM to 100 pM. In some embodiments, a binding5 affinity is between about 10 pM to 1 nM, 100 pM to 1 nM, 200 pM to 1 nM, 300 pM to 1 nM, 400 pM to 1 nM, 500 pM to 1 nM, 600 pM to 1 nM, 700 pM to 1 nM, 800 pM to 1 nM, or 900 pM to 1 nM. In some embodiments, a binding affinity is between about 1 nM to 100 nM, 10 nM to 100 nM, 20 nM to 100 nM, 30 nM to 100 nM, 40 nM to 100 nM, 50 nM to 100 nM, 60 nM to 100 nM, 70 nM to 100 nM, 80 nM to 100 nM, or 90 nM to 100 nM. In some0 embodiments, a binding affinity is between about 5 nM to 100 nM, 10 nM to 100 nM, 15 nM to 100 nM, 20 nM to 100 nM, 25 nM to 100 nM, 30 nM to 100 nM, 35 nM to 100 nM, 40 nM to 100 nM, 45 nM to 100 nM, 50 nM to 100 nM, 55 nM to 100 nM, 60 nM to 100 nM, 65 nM to 100 nM, 70 nM to 100 nM, 75 nM to 100 nM, 80 nM to 100 nM, 85 nM to 100 nM, 90 nM to 100 nM, or 95 nM to 100 nM. 5

[0387] In some embodiments, a binding affinity is about 5 pM, 10 pM, 15 pM, 20 pM, 25 pM, 30 pM, 35 pM, 40 pM, 45 pM, 50 pM, 55 pM, 60 pM, 65 pM, 70 pM, 75 pM, 80 pM, 85 pM, 90 pM, 95 pM, or 100 pM. In some embodiments, a binding affinity is about 100 pM, 150 pM, 200 pM, 250 pM, 300 pM, 350 pM, 400 pM, 450 pM, 500 pM, 550 pM, 600 pM, 650 pM, 700 pM, 750 pM, 800 pM, 850 pM, 900 pM, 950 pM, or 1 nM. In some 0 embodiments, a binding affinity is about 1 nM, 2 nM, 3 nM, 4 nM, 5 nM, 6 nM, 7 nM, 8 nM, 9 nM, or 10 nM. In some embodiments, a binding affinity is about 5 nM, 10 nM, 15 nM, 20 nM, 25 nM, 30 nM, 35 nM, 40 nM, 45 nM, 50 nM, 55 nM, 60 nM, 65 nM, 70 nM, 75 nM, 80 nM, 85 nM, 90 nM, 95 nM, or 100 nM. IPTS / 128722251.1 Page 122 of 337Docket No.: AKT-031WO

[0388] In some embodiments, a binding affinity is about 1 pM. In some embodiments, a binding affinity is about 2 pM. In some embodiments, a binding affinity is about 3 pM. In some embodiments, a binding affinity is about 4 pM. In some embodiments, a binding affinity is about 5 pM. In some embodiments, a binding affinity is about 10 pM. In some 5 embodiments, a binding affinity is about 15 pM. In some embodiments, a binding affinity is about 20 pM. In some embodiments, a binding affinity is about 25 pM. In some embodiments, a binding affinity is about 30 pM. In some embodiments, a binding affinity is about 35 pM. In some embodiments, a binding affinity is about 40 pM. In some embodiments, a binding affinity is about 45 pM. In some embodiments, a binding affinity is0 about 50 pM. In some embodiments, a binding affinity is about 55 pM. In some embodiments, a binding affinity is about 60 pM. In some embodiments, a binding affinity is about 65 pM. In some embodiments, a binding affinity is about 70 pM. In some embodiments, a binding affinity is about 75 pM. In some embodiments, a binding affinity is about 80 pM. In some embodiments, a binding affinity is about 85 pM. In some 5 embodiments, a binding affinity is about 90 pM. In some embodiments, a binding affinity is about 95 pM. In some embodiments, a binding affinity is about 100 pM. In some embodiments, a binding affinity is about 150 pM. In some embodiments, a binding affinity is about 200 pM. In some embodiments, a binding affinity is about 250 pM. In some embodiments, a binding affinity is about 300 pM. In some embodiments, a binding affinity is0 about 350 pM. In some embodiments, a binding affinity is about 400 pM. In some embodiments, a binding affinity is about 450 pM. In some embodiments, a binding affinity is about 500 pM. In some embodiments, a binding affinity is about 550 pM. In some embodiments, a binding affinity is about 600 pM. In some embodiments, a binding affinity is about 650 pM. In some embodiments, a binding affinity is about 700 pM. In some 5 embodiments, a binding affinity is about 750 pM. In some embodiments, a binding affinity is about 800 pM. In some embodiments, a binding affinity is about 850 pM. In some embodiments, a binding affinity is about 900 pM. In some embodiments, a binding affinity is about 950 pM. In some embodiments, a binding affinity is about 1 nM. In some embodiments, a binding affinity is about 2 nM. In some embodiments, a binding affinity is0 about 3 nM. In some embodiments, a binding affinity is about 4 nM. In some embodiments, a binding affinity is about 5 nM. In some embodiments, a binding affinity is about 6 nM. In some embodiments, a binding affinity is about 7 nM. In some embodiments, a binding affinity is about 8 nM. In some embodiments, a binding affinity is about 9 nM. In some embodiments, a binding affinity is about 10 nM. In some embodiments, a binding affinity is IPTS / 128722251.1 Page 123 of 337Docket No.: AKT-031WO about 15 nM. In some embodiments, a binding affinity is about 20 nM. In some embodiments, a binding affinity is about 25 nM. In some embodiments, a binding affinity is about 30 nM. In some embodiments, a binding affinity is about 35 nM. In some embodiments, a binding affinity is about 40 nM. In some embodiments, a binding affinity is 5 about 45 nM. In some embodiments, a binding affinity is about 50 nM. In some embodiments, a binding affinity is about 55 nM. In some embodiments, a binding affinity is about 60 nM. In some embodiments, a binding affinity is about 65 nM. In some embodiments, a binding affinity is about 70 nM. In some embodiments, a binding affinity is about 75 nM. In some embodiments, a binding affinity is about 80 nM. In some 0 embodiments, a binding affinity is about 85 nM. In some embodiments, a binding affinity is about 90 nM. In some embodiments, a binding affinity is about 95 nM. In some embodiments, a binding affinity is about 100 nM.

[0389] In some embodiments, a binding affinity is stronger than about 100 nM (e.g., 90 nM, 80 nM, etc.). In some embodiments, a binding affinity is no weaker than about 0.5 nM, 15 nM, 5 nM, 10 nM, 15 nM, 20 nM, 25 nM, 30 nM, 35 nM, 40 nM, 45 nM, 50 nM, 55 nM, 60 nM, 65 nM, 70 nM, 75 nM, 80 nM, 85 nM, 90 nM, 95 nM, or 100 nM. In some embodiments, a binding affinity is no weaker than about 0.5 nM. In some embodiments, a binding affinity is no greater than about 1 nM. In some embodiments, a binding affinity is no weaker than about 5 nM. In some embodiments, a binding affinity is no weaker than about 100 nM. In some embodiments, a binding affinity is no weaker than about 15 nM. In some embodiments, a binding affinity is no weaker than about 20 nM. In some embodiments, a binding affinity is no weaker than about 25 nM. In some embodiments, a binding affinity is no weaker than about 30 nM. In some embodiments, a binding affinity is no weaker than about 35 nM. In some embodiments, a binding affinity is no weaker than about 40 nM. In5 some embodiments, a binding affinity is no weaker than about 45 nM. In some embodiments, a binding affinity is no weaker than about 50 nM. In some embodiments, a binding affinity is no weaker than about 55 nM. In some embodiments, a binding affinity is no weaker than about 60 nM. In some embodiments, a binding affinity is no weaker than about 65 nM. In some embodiments, a binding affinity is no weaker than about 70 nM. In some embodiments,0 a binding affinity is no weaker than about 75 nM. In some embodiments, a binding affinity is no weaker than about 80 nM. In some embodiments, a binding affinity is no weaker than about 85 nM. In some embodiments, a binding affinity is no weaker than about 90 nM. In some embodiments, a binding affinity is no weaker than about 95 nM. In some embodiments, a binding affinity is no weaker than 100 nM. IPTS / 128722251.1 Page 124 of 337Docket No.: AKT-031WO

[0390] In some embodiments, an inhibition constant (Ki) of a polypeptide (or composition comprising such polypeptide) as provided herein is in a range of about 1 pM to about 100 nM.

[0391] In some embodiments, an inhibition constant (Ki) is between about 1 pM to 100 nM, 5 1 pM to 100 pM, 10 pM to 1 nM, 100 pM to 10 nM, or 1 nM to 100 nM. In some embodiments, an inhibition constant is between about 1 pM to 5 pM, 1 pM to 10 pM, 1 pM to 15 pM, 1 pM to 20 pM, 1 pM to 25 pM, 1 pM to 30 pM, 1 pM to 35 pM, 1 pM to 40 pM, 1 pM to 45 pM, 1 pM to 50 pM, 1 pM to 55 pM, 1 pM to 60 pM, 1 pM to 65 pM, 1 pM to 70 pM, 1 pM to 75 pM, 1 pM to 80 pM, 1 pM to 85 pM, 1 pM to 90 pM, 1 pM to 95 pM, or 10 pM to 100 pM. In some embodiments, an inhibition constant is between about 25 pM to 30 pM, 25 pM to 35 pM, 25 pM to 40 pM, 25 pM to 45 pM, 25 pM to 50 pM, 25 pM to 55 pM, 25 pM to 60 pM, 25 pM to 65 pM, 25 pM to 70 pM, 25 pM to 75 pM, 25 pM to 80 pM, 25 pM to 85 pM, 25 pM to 90 pM, 25 pM to 95 pM, or 25 pM to 100 pM. In some embodiments, an inhibition constant is between about 50 pM to 55 pM, 50 pM to 60 pM, 505 pM to 65 pM, 50 pM to 70 pM, 50 pM to 75 pM, 50 pM to 80 pM, 50 pM to 85 pM, 50 pM to 90 pM, 50 pM to 95 pM, or 50 pM to 100 pM. In some embodiments, an inhibition constant is between about 75 pM to 80 pM, 75 pM to 85 pM, 75 pM to 90 pM, 75 pM to 95 pM, or 75 pM to 100 pM. In some embodiments, an inhibition constant is between about 10 pM to 1 nM, 100 pM to 1 nM, 200 pM to 1 nM, 300 pM to 1 nM, 400 pM to 1 nM, 500 pM0 to 1 nM, 600 pM to 1 nM, 700 pM to 1 nM, 800 pM to 1 nM, or 900 pM to 1 nM. In some embodiments, an inhibition constant is between about 1 nM to 100 nM, 10 nM to 100 nM, 20 nM to 100 nM, 30 nM to 100 nM, 40 nM to 100 nM, 50 nM to 100 nM, 60 nM to 100 nM, 70 nM to 100 nM, 80 nM to 100 nM, or 90 nM to 100 nM. In some embodiments, an inhibition constant is between about 5 nM to 100 nM, 10 nM to 100 nM, 15 nM to 100 nM, 20 nM to5 100 nM, 25 nM to 100 nM, 30 nM to 100 nM, 35 nM to 100 nM, 40 nM to 100 nM, 45 nM to 100 nM, 50 nM to 100 nM, 55 nM to 100 nM, 60 nM to 100 nM, 65 nM to 100 nM, 70 nM to 100 nM, 75 nM to 100 nM, 80 nM to 100 nM, 85 nM to 100 nM, 90 nM to 100 nM, or 95 nM to 100 nM.

[0392] In some embodiments, an inhibition constant is about 5 pM, 10 pM, 15 pM, 20 pM,0 25 pM, 30 pM, 35 pM, 40 pM, 45 pM, 50 pM, 55 pM, 60 pM, 65 pM, 70 pM, 75 pM, 80 pM, 85 pM, 90 pM, 95 pM, or 100 pM. In some embodiments, an inhibition constant is about 100 pM, 150 pM, 200 pM, 250 pM, 300 pM, 350 pM, 400 pM, 450 pM, 500 pM, 550 pM, 600 pM, 650 pM, 700 pM, 750 pM, 800 pM, 850 pM, 900 pM, 950 pM, or 1 nM. In some embodiments, an inhibition constant is about 1 nM, 2 nM, 3 nM, 4 nM, 5 nM, 6 nM, 7 nM, 8 IPTS / 128722251.1 Page 125 of 337Docket No.: AKT-031WO nM, 9 nM, or 10 nM. In some embodiments, an inhibition constant is about 5 nM, 10 nM, 15 nM, 20 nM, 25 nM, 30 nM, 35 nM, 40 nM, 45 nM, 50 nM, 55 nM, 60 nM, 65 nM, 70 nM, 75 nM, 80 nM, 85 nM, 90 nM, 95 nM, or 100 nM.

[0393] In some embodiments, an inhibition constant is about 1 pM. In some embodiments, 5 an inhibition constant is about 2 pM. In some embodiments, an inhibition constant is about 3 pM. In some embodiments, an inhibition constant is about 4 pM. In some embodiments, an inhibition constant is about 5 pM. In some embodiments, an inhibition constant is about 10 pM. In some embodiments, an inhibition constant is about 15 pM. In some embodiments, an inhibition constant is about 20 pM. In some embodiments, an inhibition constant is about 250 pM. In some embodiments, an inhibition constant is about 30 pM. In some embodiments, an inhibition constant is about 35 pM. In some embodiments, an inhibition constant is about 40 pM. In some embodiments, an inhibition constant is about 45 pM. In some embodiments, an inhibition constant is about 50 pM. In some embodiments, an inhibition constant is about 55 pM. In some embodiments, an inhibition constant is about 60 pM. In some embodiments, an5 inhibition constant is about 65 pM. In some embodiments, an inhibition constant is about 70 pM. In some embodiments, an inhibition constant is about 75 pM. In some embodiments, an inhibition constant is about 80 pM. In some embodiments, an inhibition constant is about 85 pM. In some embodiments, an inhibition constant is about 90 pM. In some embodiments, an inhibition constant is about 95 pM. In some embodiments, an inhibition constant is about 1000 pM. In some embodiments, an inhibition constant is about 150 pM. In some embodiments, an inhibition constant is about 200 pM. In some embodiments, an inhibition constant is about 250 pM. In some embodiments, an inhibition constant is about 300 pM. In some embodiments, an inhibition constant is about 350 pM. In some embodiments, an inhibition constant is about 400 pM. In some embodiments, an inhibition constant is about 450 pM. In5 some embodiments, an inhibition constant is about 500 pM. In some embodiments, an inhibition constant is about 550 pM. In some embodiments, an inhibition constant is about 600 pM. In some embodiments, an inhibition constant is about 650 pM. In some embodiments, an inhibition constant is about 700 pM. In some embodiments, an inhibition constant is about 750 pM. In some embodiments, an inhibition constant is about 800 pM. In0 some embodiments, an inhibition constant is about 850 pM. In some embodiments, an inhibition constant is about 900 pM. In some embodiments, an inhibition constant is about 950 pM. In some embodiments, an inhibition constant is about 1 nM. In some embodiments, an inhibition constant is about 2 nM. In some embodiments, an inhibition constant is about 3 nM. In some embodiments, an inhibition constant is about 4 nM. In some embodiments, an IPTS / 128722251.1 Page 126 of 337Docket No.: AKT-031WO inhibition constant is about 5 nM. In some embodiments, an inhibition constant is about 6 nM. In some embodiments, an inhibition constant is about 7 nM. In some embodiments, an inhibition constant is about 8 nM. In some embodiments, an inhibition constant is about 9 nM. In some embodiments, an inhibition constant is about 10 nM. In some embodiments, an 5 inhibition constant is about 15 nM. In some embodiments, an inhibition constant is about 20 nM. In some embodiments, an inhibition constant is about 25 nM. In some embodiments, an inhibition constant is about 30 nM. In some embodiments, an inhibition constant is about 35 nM. In some embodiments, an inhibition constant is about 40 nM. In some embodiments, an inhibition constant is about 45 nM. In some embodiments, an inhibition constant is about 500 nM. In some embodiments, an inhibition constant is about 55 nM. In some embodiments, an inhibition constant is about 60 nM. In some embodiments, an inhibition constant is about 65 nM. In some embodiments, an inhibition constant is about 70 nM. In some embodiments, an inhibition constant is about 75 nM. In some embodiments, an inhibition constant is about 80 nM. In some embodiments, an inhibition constant is about 85 nM. In some embodiments, an5 inhibition constant is about 90 nM. In some embodiments, an inhibition constant is about 95 nM. In some embodiments, an inhibition constant is about 100 nM.

[0394] In some embodiments, an inhibition constant is no greater than about 0.5 nM, 1 nM, 5 nM, 10 nM, 15 nM, 20 nM, 25 nM, 30 nM, 35 nM, 40 nM, 45 nM, 50 nM, 55 nM, 60 nM, 65 nM, 70 nM, 75 nM, 80 nM, 85 nM, 90 nM, 95 nM, or 100 nM. 0

[0395] In some embodiments, an inhibition constant is no greater than about 0.5 nM. In some embodiments, an inhibition constant is no greater than about 1 nM. In some embodiments, an inhibition constant is no greater than about 5 nM. In some embodiments, an inhibition constant is no greater than about 10 nM. In some embodiments, an inhibition constant is no greater than about 15 nM. In some embodiments, an inhibition constant is no5 greater than about 20 nM. In some embodiments, an inhibition constant is no greater than about 25 nM. In some embodiments, an inhibition constant is no greater than about 30 nM. In some embodiments, an inhibition constant is no greater than about 35 nM. In some embodiments, an inhibition constant is no greater than about 40 nM. In some embodiments, an inhibition constant is no greater than about 45 nM. In some embodiments, an inhibition0 constant is no greater than about 50 nM. In some embodiments, an inhibition constant is no greater than about 55 nM. In some embodiments, an inhibition constant is no greater than about 60 nM. In some embodiments, an inhibition constant is no greater than about 65 nM. In some embodiments, an inhibition constant is no greater than about 70 nM. In some embodiments, an inhibition constant is no greater than about 75 nM. In some embodiments, IPTS / 128722251.1 Page 127 of 337Docket No.: AKT-031WO an inhibition constant is no greater than about 80 nM. In some embodiments, an inhibition constant is no greater than about 85 nM. In some embodiments, an inhibition constant is no greater than about 90 nM. In some embodiments, an inhibition constant is no greater than about 95 nM. In some embodiments, an inhibition constant is no greater than about 100 nM. 5 CDPs

[0396] In some embodiments, miniproteins of the present disclosure comprise or consist of a cysteine-dense peptides (CDPs). In some embodiments, conjugates provided herein comprise a CDP. In some embodiments, a CDP functions as a targeting moiety, e.g., specifically binding to a protein target or antigen expressed on the surface of a target tumor0 cell. In some embodiments, a CDP comprises or consists of at least two independent folding domains and a high density of cysteines. In some embodiments, the CDP comprises at least one, two, three, four, five, six, or more than six cysteine residues in a span of from about 10 to about 90 amino acid residues, preferably 13 to 80 amino acid residues. (See, e.g., Correnti et al., Nat Struct Mol Biol.2018 Mar;25(3):270-278, for exemplary CDPs and characteristics5 thereof). In some embodiments, the CDP comprises a constrained distribution of cysteines, Cys-X[0–15]-Cys-X[0–15]-Cys-X[0–15]-Cys-X[0–15]-Cys-X[0–15]-Cys (wherein X represents any amino acid) (SEQ ID NO: 241). In some embodiments, a CDP comprises one or more cysteine dense regions comprising at least one cysteine residue, preferably at least two, three, four, or more cysteine residues in a span of from about 10 to 80 amino acid0 residues. In some embodiments, a CDP can be further engineered to modify binding, folding, and / or related properties.

[0397] In some embodiments, a CDP specifically binds to a target. In some embodiments, the target is located in, on, or near a cell. In some embodiments, the CDP specifically binds to Nectin-4 or a fragment thereof. In some embodiments, a CDP is conjugated to a chelator5 and / or radionuclide. In some embodiments, conjugation is via a linker. It will be understood by those of skill in the art, that in some embodiments, the particular CDP employed in a conjugate of the present disclosure may vary depending on the target protein or antigen of interest.

[0398] In some embodiments, in miniproteins having cysteine residues, to ensure proper0 folding and connectivity, selected cysteine pairs can be replaced with selenocysteines. In some embodiments, diselenide crosslinks may form more readily than disulfide crosslinks due to their lower redox potential. In some such embodiments, such replacement can lead to cross-coupling of remaining cysteines. IPTS / 128722251.1 Page 128 of 337Docket No.: AKT-031WO Knottins

[0399] In some embodiments, miniproteins of the present disclosure comprise or consist of knottin peptides. In some embodiments, conjugates provided herein comprise a knottin peptide. In some embodiments, a knottin peptide functions as a targeting moiety, e.g., 5 specifically binding to an antigen expressed on the surface of a target tumor cell. In some embodiments, a knottin comprises at least three disulfide bonds connected in an arrangement that generates the so-called “cysteine-knot” for which knottins are named. (See, e.g., Kintzing & Cochran et al., Curr Opin Chem Biol.2016 Oct;34:143-150.). In some embodiments, knottins have high stability (e.g., thermal, proteolytic, chemical, etc.). In some embodiments,0 a knottin can be further engineered to modify binding, folding, and / or related properties.

[0400] In some embodiments, a given knottin is highly specific for a given target. In some embodiments, a knottin specifically binds to a target. In some embodiments, the target is located in, on, or near a cell. In some embodiments, the knottin specifically binds to Nectin-4 or a fragment thereof. In some embodiments, a knottin is conjugated to a chelator and / or5 radionuclide. In some embodiments, conjugation is via a linker. It will be understood by those of skill in the art, that in some embodiments, the particular knottin employed in a conjugate of the present disclosure may vary depending on the target protein or antigen of interest.

[0401] In some embodiments, folded structures of miniproteins (e.g., a linear polypeptide, a0 folded polypeptide (e.g., covalently linked polypeptide, non-covalently linked polypeptide, or polypeptide include a di-sulfide linkage), cysteine-dense peptide, a knottin peptide, a binder, an affibody, an engineered Kunitz domain, a monobody, an anticalin, a designed ankyrin repeat domain (DARPin), or an avimer) make them rigid, providing for very tight and potent binding to the target protein or antigen (relative to less structured peptides). In some such5 embodiments, a miniprotein exhibits extraordinary stability with resistance to heat, peptidase cleavage, and pH. Binders

[0402] In some embodiments, a miniprotein of the present disclosure comprises or consists of a binder. In some embodiments, the binder functions as a targeting moiety, e.g., 0 specifically binding to a target expressed on the surface of a tumor cell.

[0403] In some embodiments, a binder has certain structural features; for example, in some embodiments, a binder may be rich in alpha-helices, such as a helix-helix-helix structure (see, e.g., Crook et al., Nat Commun. (2017) 8, 2244; Berger et al, Elife (2016) 5, e20352; and IPTS / 128722251.1 Page 129 of 337Docket No.: AKT-031WO Procko et al., Cell (2014), 157, 1644-1656). In some embodiments, a binder comprises sufficient surface to functionalize the molecule on a disparate surface to a binding surface. In some embodiments, a binder comprises a sequestered hydrophobic core. In some embodiments...

Claims

Docket No.: AKT-031WO CLAIMS What is claimed is:

1. A composition, comprising a polypeptide of at least 44 amino acids in length and having an amino sequence comprising that set forth in SEQ ID NO: 171, wherein X2 5 is E or D; X6 is E or Q; X17 is G or A; X21 is Q, Y, or E; X26 is Kme3, Kme2, Kme, K, Kipr, or S; X32 is A, G, or D; X41 is N or K; and X45 is S or absent.

2. A composition, comprising a polypeptide of at least 44 amino acids in length and having an amino acid sequence comprising that set forth in SEQ ID NO: 176, wherein0 X2 is E or D; X6 is E or Q; X9 is T or A; X10 is A or G; X12 is A, Kme3, Kme2, Kme, Kipr or K; X13 is R or (Cit) X17 is G or A; X21 is Q, Y, or E; X24 is Q or K; X25 is A or K; X26 is Kme3, Kme2, Kme, K, Kipr, or S; X28 is Q or K; X29 is Y or K; X30 is L or V; X32 is A, G, or D; X41 is N or K; and X45 is S or absent. 5 3. A composition, comprising a Nectin-4 binding polypeptide having an amino acid sequence comprising at least 44 amino acids, wherein the amino acids include (i) a cysteine at each of four positions corresponding to 1, 20, 34, and 44 of SEQ ID NO: 195; (ii) SEQ ID NO: 169 at positions corresponding to positions 9-15 of SEQ ID NO: 195; (iii) QKKme3 at positions corresponding to positions 24, 25, and 26 of SEQ0 ID NO: 195; and (iv) QYL at positions corresponding to positions 28, 29, and 30 of SEQ ID NO:

195.

4. A composition, comprising a Nectin-4 binding polypeptide having an amino acid sequence comprising at least 44 amino acids, wherein the amino acids include (i) a5 cysteine at each of four positions corresponding to 1, 20, 34, and 44 of SEQ ID NO: 200; (ii) SEQ ID NO: 247 at positions corresponding to positions 9-15 of SEQ ID NO: 200; (iii) QKKme3 at positions corresponding to positions 24, 25, and 26 of SEQ ID NO: 200; and (iv) QYL at positions corresponding to positions 28, 29, and 30 of SEQ ID NO:

200. 0 5. A composition, comprising a Nectin-4 binding polypeptide having an amino acid sequence, wherein the amino acid sequence comprises: a. at least four cysteines, which form two disulfide bonds; IPTS / 128722251.1 Page 314 of 337Docket No.: AKT-031WO b. at least one modified lysine residue at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the modification comprises at least one small alkyl group attached to the nitrogen of the lysine side chain, optionally comprising a methyl, dimethyl, trimethyl, or isopropyl group; 5 c. at least 44 amino acids in length; and d. has a binding affinity for Nectin-4 stronger than 100 nM in a cell-based assay.

6. The composition of any one of the preceding claims, wherein the polypeptide is at least 40 amino acids in length, but no greater than 100 amino acids in length. 0 7. The composition of any one of the preceding claims, wherein the polypeptide binds to Nectin-4 with an affinity of stronger than 10 nM in a cell-based assay.

8. The composition of any one of the preceding claims, wherein the amino acid sequence5 of the polypeptide shares at least 90% identity to any one of SEQ ID NOs: 3-158, 161-168, 177-208, or 212-215, but includes at least one lysine with at least one modification comprising at least one small alkyl group bonded to the nitrogen of the side chain, optionally selected from: trimethyl, dimethyl, monomethyl, and isopropyl. 0 9. The composition of any one of the preceding claims, wherein the amino acid sequence of the polypeptide shares at least 90% identity to at least 44 amino acids of a reference polypeptide, which reference polypeptide is longer than 44 amino acids in length and binds to Nectin-4 with a strength of at least 10 nM on a cell-based assay, and / or has an inhibition constant of no greater than 10 nM. 5 10. The composition of any one of the preceding claims, wherein the amino acid sequence of the polypeptide shares at least 90% identity to at least 40 amino acids of any one of SEQ ID NOs: 3-158, 161-168, 177-208, or 212-215, provided that the 40 amino acids includes at least four cysteine residues that form two disulfide bridges. 0 11. The composition of any one of the preceding claims, wherein the amino acid sequence of the polypeptide shares at least 90% identity to at least 35 contiguous amino acids of any one of SEQ ID NOs: 3-158, 161-168, 177-208, or 212-215, provided that the 40 amino acids includes at least four cysteine residues that form two disulfide bridges. IPTS / 128722251.1 Page 315 of 337Docket No.: AKT-031WO 12. The composition of any one of the preceding claims, wherein the amino acid sequence of the polypeptide shares 100% identity to at least 44 amino acids of a reference polypeptide, which reference polypeptide is longer than 44 amino acids in length. 5 13. The composition of any one of the preceding claims, wherein the amino acid sequence shares 90% identity to at least 44 amino acids as set forth in any one of SEQ ID NO: 78, 83, 85, 99, 103, 162-168, 195, or 200. 0 14. The composition of any one of the preceding claims, wherein the amino acid sequence shares 100% identity to at least 44 amino acids as set forth in any one of SEQ ID NO: 78, 83, 85, 99, 103, 162-168, 195, or 200.

15. A composition comprising a polypeptide having an amino acid sequence comprising5 SEQ ID NO:

195.

16. A composition comprising a compound as set forth in C251 of Table 2A, having an amino acid sequence comprising SEQ ID NO: 195 0 17. A composition comprising a polypeptide having an amino acid sequence comprising SEQ ID NO:

200.

18. A composition comprising a compound as set forth in C260 of Table 2A, having an amino acid sequence comprising SEQ ID NO:

200. 5 19. The composition of any one of claims 13-18, further comprising a radionuclide.

20. The composition of claim 19, wherein the radionuclide is Ac-225, Cu-64, Ga-68, Lu- 177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-0 232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

21. A composition comprising a polypeptide having an amino acid sequence of at least 44 amino acids in length, but with four amino acid substitutions at positions IPTS / 128722251.1 Page 316 of 337Docket No.: AKT-031WO corresponding to 12, 21, 26, and 32 of SEQ ID NO: 78, wherein the substitutions correspond to K12A, Y21Q, S26Kme3, and G32A.

22. The composition of any one of the preceding claims, wherein the C-terminus has an - 5 OH or an -NH2.

23. The composition of any one of the preceding claims, wherein the binding affinity for Nectin-4 is stronger than 100 nM. 0 24. The composition of any one of the preceding claims, wherein the inhibition constant is no greater than 100 nM.

25. The composition of any one of the preceding claims, further comprising one or more of a linker, chelator, and radionuclide. 5 26. The composition of claim 25, wherein the linker comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG2, PEG, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a0 propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n- (gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof.

27. The composition of claim 25 or 26, wherein the chelator comprises or consists of5 DOTA, Crown, NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri- n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

28. The composition of any one of claims 25-27, wherein the radionuclide is selected0 from Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce- 134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

29. The composition of any one of claims 25-28, wherein if the polypeptide comprises any one of SEQ ID NO: 83, 85, 93, 99, 134, 138, 145, 155, 162-168, or 195 the IPTS / 128722251.1 Page 317 of 337Docket No.: AKT-031WO polypeptide further comprises a linker, wherein the linker is PEG4, and an optional chelator, wherein the chelator is DOTA.

30. The composition of any one of claims 25-29, wherein, when present, the linker is 5 attached to the N-terminus of the polypeptide.

31. The composition of any one of the preceding claims, wherein the C-terminal amino acid of the polypeptide is not a cysteine. 0 32. The composition of any one of claims 25-31, wherein, when present, the chelator is attached to either the polypeptide or the linker.

33. The composition of any one of claims 25-32, wherein, when present, the radionuclide is attached to the chelator. 5 34. A composition comprising a formula selected from one or more of (M)x-L-C-R, (M)x-L-C, (M)x-C-R, (M)x-L-R, (M)x-C, (M)x-L, and (M)x-R, wherein M comprises a polypeptide (M), L comprises a linker (L), C comprises a chelator (C), R comprises a radionuclide (R), and x is 1, 2, 3, or 4, wherein M comprises an amino acid0 sequence of any one of SEQ ID NO: 3-158, 161-168, 170-208, 212-237, 243-246 or 248.

35. The composition of claim 34, wherein the linker comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12,5 PEG24, PEG36, lys(MPB)-PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n- (gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof. 0 36. The composition of claim 34 or 35, wherein the chelator comprises or consists of DOTA, Crown, NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri- n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB). IPTS / 128722251.1 Page 318 of 337Docket No.: AKT-031WO 37. The composition of any one of claims 34-36, wherein the radionuclide Ac-225, Cu- 64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I- 124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211. 5 38. A composition comprising a formula selected from one or more of (M)x-L-C-R, (M)x-L-C, (M)x-C-R, (M)x-L-R, (M)x-C, (M)x-L, and (M)x-R, wherein M comprises a polypeptide (M), L comprises a linker (L), C comprises a chelator (C), R comprises a radionuclide (R), and x is 1, 2, 3, or 4, wherein M has an amino acid sequence0 comprising any one of those set forth in SEQ ID NOs: 162-176, 178-208, or 212-215.

39. The composition of claim 38, wherein, when L is present, L comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, lys(MPB)-PEG4, PEG36, an ester linker, an amide linker, a maleimide linker5 a valine-citrulline linker, a hydrazone linker, a N-succinimidyl-4-(2- pyridyldithio)butyrate (SPDB) linker, a succinimidyl-4-(N- maleimidomethyl)cyclohexane-1-carboxylate (SMCC) linker, a vinylsulfone-based linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment0 or combination via covalent bond thereof.

40. The composition of claim 38 or 39, wherein, when C is present, C comprises or consists of DOTA, Crown, NOPO, Macropa, lead-specific chelator (PSC), N- succinimidyl 3-(tri-n-butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-5 trimethylstannylbenzoate (MeSTB).

41. The composition of any one of claims 38-40, wherein when R is present, R comprises or consists of Ac-225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-0 211.

42. The composition of any one of claims 38-41, wherein, when present, the linker is attached to the N-terminus of the polypeptide. IPTS / 128722251.1 Page 319 of 337Docket No.: AKT-031WO 43. The composition of claim 42, wherein the C-terminal amino acid of the polypeptide is not a cysteine.

44. The composition of any one of claims 38-43, wherein, when present, the chelator is 5 attached to either the polypeptide or the linker.

45. The composition of any one of claims 38-44, wherein, when present, the radionuclide is attached to the chelator. 0 46. The composition of any one of claims 38-45, wherein the polypeptide comprises at least one disulfide bridge.

47. The composition of claim 46, wherein the polypeptide comprises at least two disulfide bridges. 5 48. The composition of any one of the preceding claims, which composition and / or polypeptide thereof selectively binds to Nectin-4 or a portion thereof.

49. The composition of any one of the preceding claims, wherein the polypeptide has a0 binding affinity for Nectin-4 or a portion thereof of 10 pM to 200 nM, 10 pM to 100 nM, or 10 nM to 100 nM, in vivo, ex vivo, or in vitro and / or as measured in a cell- based assay.

50. The composition of any one of the preceding claims, wherein the polypeptide has a5 binding inhibition constant of no greater than 100 nM.

51. A composition comprising a polypeptide-drug conjugate, comprising a polypeptide and at least one drug moiety, wherein the polypeptide comprises an amino acid0 sequence having at least 90% identity to at least 44 amino acids a polypeptide having an amino acid sequence set forth in any one of SEQ ID NOs: 3-158, 161-168, 170- 208, 212-237, 243-246 and 248. IPTS / 128722251.1 Page 320 of 337Docket No.: AKT-031WO 52. The composition of claim 51, wherein the drug moiety is selected from a V-ATPase inhibitor, a pro-apoptotic agent, a Bcl2 inhibitor, an MCL1 inhibitor, a HSP90 inhibitor, an IAP inhibitor, an mTor inhibitor, a microtubule stabilizer, a microtubule destabilizer, an auristatin, a dolastatin, a maytansinoid, a MetAP (methionine 5 aminopeptidase), an inhibitor of nuclear export of proteins CRMl, a DPPIV inhibitor, proteasome inhibitors, inhibitors of phosphoryl transfer reactions in mitochondria, a protein synthesis inhibitor, a kinase inhibitor, a CDK2 inhibitor, a CDK9 inhibitor, a kinesin inhibitor, an HDAC inhibitor, a DNA damaging agent, a DNA alkylating agent, a DNA intercalator, a DNA minor groove binder, a DHFR inhibitor, a0 topoisomerase inhibitor, an auristatin (e.g., monomethyl auristatin E), and an immunotoxin.

53. A composition comprising an isolated compound or pharmaceutically acceptable salt thereof comprising an optional linker (L), and one or more of a polypeptide (M),5 chelator (C) or radionuclide (R), wherein M has an amino acid sequence comprising any one of SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246 and 248, including amino acid substitutions as set forth in Table 1C, Table 1D, Table 2C, Table 2D, Table 2E, Table 2F, or Table 2G. 0 54. A composition comprising, a compound designed to bind to Nectin-4, which compound comprises or consists of a polypeptide having an amino acid sequence comprising any one of SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246 and 248, including amino acid substitutions as set forth in Table 1C, Table 1D, Table 2C, Table 2D, Table 2E, Table 2F, or Table 2G, and further comprises a modified N5 and / or C-terminus.

55. The composition of claim 54, wherein the modified N-terminus comprises one or more of an NH2-, Acetyl-, PEGn-, wherein n=0-10, DOTA-, or Biotin-. 0 56. The composition of any one of the preceding claims, wherein the C terminus comprises an -NH2 or an -OH.

57. The composition of any one of the preceding claims, wherein the polypeptide selectively binds to Nectin-4 or a portion thereof. IPTS / 128722251.1 Page 321 of 337Docket No.: AKT-031WO 58. The composition of any one of the preceding claims, wherein the polypeptide has a binding affinity of stronger than about 100 nM to Nectin-4, or a portion thereof, in vivo or in a cell-based assay. 5 59. A compound comprising a miniprotein having an amino acid sequence with 90% identity to SEQ ID NO: 195, and further comprising one or more additional components according to a formula M-L-C-R, wherein L is a linker, C is a chelator, and R is a radionuclide. 0 60. The compound of claim 59, wherein L comprises or consists of a polyethylene glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl- 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid5 linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, any linker set forth in Table 2A, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via covalent bond thereof.

61. The compound of claim 59 or 60, wherein C comprises or consists of DOTA, Crown,0 NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n- butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

62. The compound of any one of claims 59-61, wherein R comprises or consists of Ac-5 225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I- 131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

63. A compound comprising a miniprotein 90% identical to at least 40 amino acids of the amino acid sequence of SEQ ID NO: 195, wherein the N and / or C-terminus comprise0 between one and thirty additional amino acids, and / or wherein the C-terminus comprises one fewer amino acids or up to 30 additional amino acids, provided that the entire miniprotein is no greater than about 100 amino acids in length. IPTS / 128722251.1 Page 322 of 337Docket No.: AKT-031WO 64. In a method of improving binding affinity strength of a polypeptide to Nectin-4, the improvement comprising modifying four amino acid residues of a polypeptide, which polypeptide has at least 44 amino acids in length and has substitutions at positions corresponding to 12, 21, 26, and 32 of SEQ ID NO: 78, wherein the substitutions 5 correspond to K12A, Y21Q, S26Kme3, and G32A.

65. A pharmaceutical composition comprising a polypeptide of any one of claims 1-58 or compound as set forth in any one of claims 59-63; and a pharmaceutically acceptable excipient. 0 66. A method of treating cancer, the method comprising administering to a subject in need thereof, a composition comprising a conjugate comprising a polypeptide having at least 90% identity to at least 40 amino acids of an amino acid sequence as set forth in any one of SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246 and 248 and5 a radionuclide.

67. The method of claim 66, wherein the radionuclide is associated with the polypeptide with a linker and / or chelator according to a formula M-L-C-R, wherein M is the polypeptide, L is a linker, C is a chelator, and R is the radionuclide. 0 68. The method of claim 66 or 67, wherein the polypeptide has an amino acid sequence comprising or consisting of SEQ ID NO: 195 or SEQ ID NO:

200.

69. The method of claim 67 or 68, wherein L comprises or consists of a polyethylene5 glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl- 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, any linker set forth in Table 2A, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any0 fragment or combination via covalent bond thereof.

70. The method of any one of claims 67-69, wherein C comprises or consists of DOTA, Crown, NOPO, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n- IPTS / 128722251.1 Page 323 of 337Docket No.: AKT-031WO butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate (MeSTB).

71. The method of any one of claims 67-70, wherein R is Ac-225, Cu-64, Ga-68, Lu-177, 5 Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I-131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211.

72. The method of claim 71, wherein R is a therapeutic agent and / or an imaging agent. 0 73. The method of claim 71 or 72, wherein R is Cu-64, Ga-68, Lu-177, In-111, Cu-67, La-132, or F-18.

74. A method of reducing kidney cell uptake of a composition comprising administering to a subject a Nectin-4 binding protein having an amino acid sequence comprising at5 least one modified lysine residue at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the modification comprises at least small alkyl group attached to the nitrogen of the lysine side chain, optionally comprising a monomethyl, dimethyl, trimethyl, or isopropyl group and the reduction is as compared to administration to the subject or a control subject an otherwise identical composition0 but not comprising the modified lysine residue at the position corresponding to X12 and / or X26.

75. In a method of treating cancer, the improvement comprising administering a composition comprising a Nectin-4 binding protein having an amino acid sequence5 comprising at least one modified lysine residue at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the modification comprises at least one carbon attached to the nitrogen of the lysine side chain, optionally comprising a methyl, dimethyl, trimethyl, or isopropyl group as compared to a composition not comprising a modified lysine residue at a position corresponding to X12 and / or X26. 0 76. A method of treating a subject with refractory or recurrent cancer comprising administering the composition according to any one of claims 1-58, the compound of any one of claims 59-63, or the pharmaceutical composition of claim 65, wherein the treatment treats the cancer. IPTS / 128722251.1 Page 324 of 337Docket No.: AKT-031WO 77. A method of improving biodistribution of a pharmaceutical composition for a Nectin- 4 positive population of cancer cells in a subject having a Nectin-4-positive cancer, comprising contacting the population with a polypeptide that has a modified lysine at a position corresponding to X12 and / or X26 of SEQ ID NO: 195, wherein the lysine 5 is modified by adding at least one small alkyl group to a lysine side chain and wherein the biodistribution is improved as compared to contacting the population without the modified lysine at a position corresponding to X12 and / or X26 of SEQ ID NO:

195.

78. A method of diagnosing presence of a Nectin-4 positive population of cancer cells0 comprising: a. contacting a population of cells with the composition according to any one of claims 1-58, the compound of any one of claims 59-63, or the pharmaceutical composition of claim 65; b. detecting the presence of the composition, compound, or pharmaceutical5 composition of step (a) by measuring a signal; and c. comparing the detection in step (b) to a control signal; and d. diagnosing cancer if the composition, compound, or pharmaceutical composition of step (a) is detected above the control. 0 79. The method of claim 78, wherein the contacting is performed by administering to a subject in need thereof.

80. The method of claim 79, wherein the administering is intravenous or subcutaneous. 5 81. The method of claim 78, wherein the contacting is outside of the subject, optionally in vitro with a biopsy sample.

82. A method of treating a cancer in a subject using an immunotherapy, the method comprising administering to the subject a composition comprising the composition as0 set forth in claims 1-58, the compound of any one of claims 59-63, or the pharmaceutical composition of claim 65.

83. Use of the composition of any one of claims 1-58, the compound of any one of claims 59-63, or the pharmaceutical composition of claim 65 to treat cancer in a subject. IPTS / 128722251.1 Page 325 of 337Docket No.: AKT-031WO 84. A method of treating a subject in need thereof comprising administering to the subject in need thereof the composition of any one of claims 1-58, the compound of any one of claims 59-63, or the pharmaceutical composition of claim 65. 5 85. The method of claim 84, wherein the subject is diagnosed as having cancer.

86. The method of claim 85, wherein a cancer cell from the subject expresses Nectin-4, or a portion thereof. 0 87. The method of claim 86, wherein the expression of Nectin-4 is higher in the cancer cell than in a non-cancer cell, which expression can be measured by protein and / or nucleic acid levels. 5 88. The method of any one of claims 84-87, wherein the composition, compound, or pharmaceutical composition is not taken up and / or retained in the kidney as compared to a compound that does not comprise the composition of any one of claims 1-58, the compound of any one of claims 59-63, or the pharmaceutical composition of claim 65. 0 89. The method of any one of claims 84-88, wherein the composition, compound, or pharmaceutical composition is internalized in a cell expressing human Nectin-4.

90. The method of any one of claims 84-89, wherein the cancer is selected from breast5 cancer, ovarian cancer, melanoma, pancreatic cancer, peripheral neuroma, glioblastoma, adrenocortical carcinoma, AIDS-related lymphoma, anal cancer, urothelial cancer, bladder cancer, meningioma, glioma, astrocytoma, cervical cancer, chronic myeloproliferative disorders, colon cancer, endometrial cancer, ependymoma, esophageal cancer, Ewing’s sarcoma, extracranial germ cell tumors, extrahepatic bile0 duct cancer, gallbladder cancer, gastric cancer, gastrointestinal carcinoid tumors, gestational trophoblastic tumors, hairy cell leukemia, Hodgkin lymphoma, non- Hodgkin lymphoma, hypopharyngeal cancer, islet cell carcinoma, Kaposi sarcoma, laryngeal cancer, leukemia, lip cancer, oral cavity cancer, liver cancer, male breast cancer, malignant mesothelioma, medulloblastoma, Merkel cell carcinoma, metastatic IPTS / 128722251.1 Page 326 of 337Docket No.: AKT-031WO squamous neck cell carcinoma, multiple myeloma and other plasma cell neoplasms, mycosis fungoides and Sezary syndrome, myelodysplastic syndromes, nasopharyngeal cancer, neuroblastoma, non-small cell lung cancer, small cell lung cancer, head and neck cancer, skin cancer, oropharyngeal cancer, bone cancers, 5 including osteosarcoma and malignant fibrous histiocytoma of bone, paranasal sinus cancer, parathyroid cancer, penile cancer, pheochromocytoma, pituitary tumors, prostate cancer, rectal cancer, renal cell cancer, retinoblastoma, rhabdomyosarcoma, salivary gland cancer, small intestine cancer, soft tissue sarcoma, supratentorial primitive neuroectodermal tumors, pineoblastoma, testicular cancer, thymoma, thymic0 carcinoma, thyroid cancer, transitional cell cancer of the renal pelvis and ureter, urethral cancer, uterine sarcoma, vaginal cancer, vulvar cancer, and Wilms tumor and other childhood kidney tumors.

91. The method of any one of claims 84-90, wherein the composition, compound, or5 pharmaceutical composition is administered intravenously or subcutaneously.

92. A method of targeting cancer cells expressing Nectin-4, the method comprising: (i) determining or having determined a level of expression of Nectin-4 in a population of cancer cells; 0 (ii) administering to a subject in need thereof a composition comprising the composition according to any one of claims 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65, wherein the polypeptide of the composition, compound, or pharmaceutical composition is designed to specifically bind to human Nectin-4 and (iii) wherein the composition,5 compound, or pharmaceutical composition is attached to the surface and / or internalized into one or more Nectin-4 expressing cancer cells.

93. The method of claim 92, wherein the subject is treated after the administering as compared to prior to the administering. 0 94. In a method of targeting a population of cancer cells expressing Nectin-4, the improvement comprising contacting the population with the composition according to any one of claims 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65, wherein X12 and / or X26 comprise a lysine IPTS / 128722251.1 Page 327 of 337Docket No.: AKT-031WO with at least one additional small alkyl group attached to the nitrogen in the side chain, wherein the composition is taken up less by kidney cells than in a composition comprising a polypeptide that does not have a small alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26, wherein, optionally, the 5 small alkyl group is part of a monomethyl, dimethyl, trimethyl, or isopropyl group.

95. A conjugate comprising: (i) a polypeptide (M) that specifically binds to Nectin-4; (ii) a chelator (C) conjugated to (M) through an optional linker (L), wherein (C)0 comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is Actinium-225.

96. A conjugate comprising: 5 (i) a polypeptide (M) that specifically binds to Nectin-4; (ii) a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is Copper- 64. 0 97. A conjugate comprising: (i) a polypeptide (M) that specifically binds to Nectin-4; (ii) a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is5 optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is Gallium- 68.

98. A conjugate comprising: (i) a polypeptide (M) that specifically binds to Nectin-4; 0 (ii) a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is Indium- 111. IPTS / 128722251.1 Page 328 of 337Docket No.: AKT-031WO 99. A conjugate comprising: (i) a polypeptide (M) that specifically binds to Nectin-4; (ii) a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is5 optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is Lead- 212.

100. A conjugate comprising: (i) a polypeptide (M) that specifically binds to Nectin-4; 0 (ii) a chelator (C) conjugated to (M) through an optional linker (L), wherein (C) comprises DOTA, and (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and (iii) a radionuclide (R) chelated to (C), wherein (R) is Lutetium-177. 5 101. A conjugate comprising: (i) a miniprotein (M) that specifically binds to Nectin-4; (ii) an N-terminal modification, conjugated to (M) through an optional linker (L), wherein (L), when present, comprises PEG, wherein the PEG is optionally PEG-4; and 0 (iii) the N-terminal modification comprises a biotin.

102. The conjugate of any one of claims 95-100, wherein M has an amino acid sequence comprising any one of the amino acid sequences set forth in SEQ ID NOs: 3-158, 161-168, 170-208, 212-237, 243-246 and 248. 5 103. The conjugate of any one of claims 95-102 wherein the amino acid sequence has at least 90% identity to that of at least 40 amino acids of SEQ ID NO: 176, wherein X2 is E or D; X6 is E or Q; X9 is T or A; X10 is A or G; X12 is A, Kme3, Kme2, Kme, Kipr or K; X13 is R or (Cit) X17 is G or A; X21 is Q, Y, or E; X24 is Q or K; X25 is0 A or K; X26 is Kme3, Kme2, Kme, K, Kipr, or S; X28 is Q or K; X29 is Y or K; X30 is L or V; X32 is A, G, or D; X41 is N or K; and X45 is S or absent.

104. The conjugate of any one of claims 95-103, wherein M has an amino acid sequence comprising or consisting of SEQ ID NO:

195. IPTS / 128722251.1 Page 329 of 337Docket No.: AKT-031WO 105. The conjugate of any one of claims 95-104, wherein M has an amino acid sequence comprising or consisting of SEQ ID NO:

200. 5 106. An isolated polynucleotide comprising one or more nucleic acid sequences encoding a polypeptide selected from any one of SEQ ID NOs: 3-158, 161-168, 170-208, 212- 237, 243-246 and 248; or a nucleic acid sequence encoding a polypeptide comprising at least 90%, 95%, 96%, 97%, 98%, 99% or greater identity to any one of SEQ ID NOs3-158, 161-168, 170-208, 212-237, 243-246 and 248. 0 107. A vector comprising the isolated polynucleotide of claim 106.

108. A host cell transformed with the isolated polynucleotide of claim 106 or the vector of claim 107. 5 109. A method of evaluating locations of one or more populations of cancerous cells in a subject, the method comprising administering to the subject the composition of any one of claims 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65 and detecting to determine location of the0 composition in the subject.

110. In a method of decreasing kidney uptake of a composition administered to detect and / or treat one or more populations of cancer cells, the improvement comprising administering to a subject in need thereof the composition according to any one of5 claims 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65, wherein X12 and / or X26 comprise a lysine with at least one additional small alkyl group attached to the nitrogen in the side chain, wherein the composition is taken up less by kidney cells than in a composition comprising a polypeptide that does not have a small alkyl group attached to a nitrogen0 on the side chain of a lysine at positions X12 and / or X26, wherein, optionally, the small alkyl group is part of a monomethyl, dimethyl, trimethyl, or isopropyl group.

111. The method of claim 109 or 110, wherein the detecting comprises an imaging procedure allows for selecting subjects, monitoring subjects, and / or treating subjects IPTS / 128722251.1 Page 330 of 337Docket No.: AKT-031WO with a therapeutic comprising a miniprotein designed to bind to Nectin-4 expressed on one or more cancer cells in the one or more populations of cancer cells.

112. The method of claim 111, wherein the therapeutic comprises the composition of any 5 one of claims 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65 or the conjugate of any one of claims 95-105.

113. A method of improving delivery of a radionuclide to a population of cancer cells in a subject, the method comprising administering the composition of any one of claims0 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65 or the conjugate of any one of claims 95-105, wherein the amino acid sequences of the polypeptide comprise amino acids corresponding to positions X12 and / or X26 of SEQ ID NO: 195, and wherein X12 and / or X26 comprise a lysine with at least one additional small alkyl group attached to the5 nitrogen in the side chain, wherein uptake by kidney cells is less than with a polypeptide having an amino acid sequence that does not comprise an additional small alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26. 0 114. The method of claim 113, wherein the small alkyl group comprises a monomethyl, dimethyl, trimethyl, or isopropyl group.

115. In a method of treating an individual with cancer, the improvement comprising reducing one or more off-target effects or toxicity measures by administering the5 composition of any one of claims 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65 or the conjugate of any one of claims 95-105, wherein the amino acid sequences of the polypeptide comprise amino acids corresponding to positions X12 and / or X26 of SEQ ID NO: 195, and wherein X12 and / or X26 comprise a lysine with at least one additional small alkyl group0 attached to the nitrogen in the side chain, wherein uptake by kidney cells is less than with a polypeptide having an amino acid sequence that does not comprise an additional small alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26. IPTS / 128722251.1 Page 331 of 337Docket No.: AKT-031WO 116. In a method of treating an individual with cancer, the improvement comprising achieving a reduction in concentration of R in a kidney tissue in the presence of the composition of any one of claims 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65 or the conjugate of any one of 5 claims 95-105, wherein the amino acid sequences of the polypeptide comprise amino acids corresponding to positions X12 and / or X26 of SEQ ID NO: 195, and wherein X12 and / or X26 comprise a lysine with at least one additional small alkyl group attached to the nitrogen in the side chain, wherein uptake by kidney cells is less than with a polypeptide having an amino acid sequence that does not comprise a small0 alkyl group attached to a nitrogen on the side chain of a lysine at positions X12 and / or X26. as compared to the concentration of R in the kidney tissue in the absence the composition, compound, pharmaceutical composition, or conjugate.

117. The method of claim 116, wherein the reduction in concentration of R in the kidney5 tissue is measured by urine output of R as measured by percent of administered radiation recovered or by detection as measured by a cell-based in vitro assay, or an in vivo detection assay.

118. The method of claim 117, wherein the administration of the composition can be0 repeated at least 2, 3, 4, 5, 6, or 7 times more in the presence of the composition having 90% identity to at least 40 amino acids of SEQ ID NO: 195 including a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO: 195 than in the presence of an A or K at positions corresponding to X12 and / or X26. 5 119. In a method of reducing uptake by a kidney tissue of a composition, the improvement comprising administering a composition comprising (a) a radionuclide therapeutic comprising at least a polypeptide and a radionuclide (R); wherein the polypeptide has at least 90% identity to 40 amino acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO:0 195, such that in the presence of the modified lysine, the radionuclide is less concentrated in the kidney tissue than in the absence of the polypeptide.

120. A method comprising administering to a subject in need thereof a compound that binds to Nectin-4 and includes one or two modified lysines at positions corresponding IPTS / 128722251.1 Page 332 of 337Docket No.: AKT-031WO to X12 and / or X26, respectively, of SEQ ID NO: 195, wherein administration of the compound having a miniprotein with the one or two modified lysines reduces one or more off target effects, toxicity grades, and / or uptake and / or retention in a kidney tissue as compared to a compound having an alanine or unmodified lysine at a 5 position corresponding to X12 and an unmodified lysine at a position corresponding to X26.

121. A method of treating an individual having or suspected of having a Nectin-4- positive cancer, the method comprising administering to the individual: 0 a. a means for blocking uptake and / or retention of a radiotherapeutic to kidney tissue, and b. a linker, a chelator, and a radionuclide.

122. The method of claim 121, wherein the means for blocking uptake and / or retention of5 a radiotherapeutic to kidney tissue binds to Nectin-4 and includes one or two modified lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195 and / or has at least 90% identity to 40 amino acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO:

195. 0 123. The method of claim 122, wherein the means for blocking uptake and / or retention of a radiotherapeutic to kidney tissue binds to Nectin-4 and includes one or two modified lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195 and / or has at least 90% identity to 35 contiguous amino acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ5 ID NO:

195.

124. The method of any one of claims 121-123, wherein the means for blocking uptake and / or retention of a radiotherapeutic to the kidney tissue blocks uptake and / or retention to the kidney tissue greater than as compared to the blocking of uptake0 and / or retention to the kidney tissue by a means that does not include one or two modified lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195 and / or has at least 90% identity to 40 amino acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO:

195. IPTS / 128722251.1 Page 333 of 337Docket No.: AKT-031WO 125. The method of any one of claims 121-124, wherein the means for blocking uptake and / or retention of a radiotherapeutic to the kidney tissue blocks uptake and / or retention to the kidney tissue greater than as compared to the blocking of uptake 5 and / or retention to the kidney tissue by a means that does not include one or two modified lysines at positions corresponding to X12 and / or X26, respectively, of SEQ ID NO: 195 and / or has at least 90% identity to 35 contiguous amino acids of SEQ ID NO: 195 and / or has a modified lysine at positions corresponding to X12 and / or X26 of SEQ ID NO:

195. 0 126. The method of any one of claims 121-125, wherein the means for blocking uptake and / or retention of a radiotherapeutic to the kidney tissue is a radiotherapeutic.

127. The method of claim 126, wherein the radiotherapeutic is targeted to a tumor or a5 population of cancer cells.

128. The method of claim 127, wherein the radiotherapeutic targeted to the tumor or the population of cancer cells is at a greater concentration than in the absence of the means for binding to kidney tissue. 0 129. The method of claim 128, wherein the radiotherapeutic comprises a polypeptide that targets Nectin-4.

130. The method of any one of claims 121-129, wherein the radiotherapeutic comprises5 or consists of a compound selected from C3-C293 or C298-C307.

131. The method of claim 130, wherein the radionuclide of the radiotherapeutic is selected from Ac-225, Cu-64, Ga-68, In-111, Lu-177, or Pb-212. 0 132. A kit comprising a polypeptide and instructions for use, wherein the polypeptide has an amino acid sequence as set forth in a polypeptide of any one of the composition of any one of claims 1-58, the compound according to any one of claims 59-63, or the pharmaceutical composition of claim 65 or the conjugate of any one of claims 95-105. IPTS / 128722251.1 Page 334 of 337Docket No.: AKT-031WO 133. The kit of claim 132, further comprising one or more of a linker, chelator, and radionuclide.

134. The kit of claim 133, wherein the linker comprises or consists of a polyethylene 5 glycol (PEG) linker of PEG4, PEG, PEG2, PEG6, PEG8, PEG12, PEG24, PEG36, lys(MPB)-PEG4, an ester linker, an amide linker, a maleimide linker, a succinimidyl- 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, a propanoic acid linker, a dTyr-Gly-Phe (yGF) linker, a caproleic acid linker, or (Gly)n-(gGlu)n- or (PEG)n, wherein n is from 1 to 10, (Gly)1-10, or any fragment or combination via0 covalent bond thereof.

135. The kit of claim 133 or 134, wherein the chelator comprises or consists of DOTA, NOPO, Crown, Macropa, lead specific chelator (PSC), N-succinimidyl 3-(tri-n- butylstannyl)benzoate (BuSTB), or N-succinimidyl 3-trimethylstannylbenzoate5 (MeSTB).

136. The kit of any one of claims 132-135, wherein prior to use, the compound is labeled with a radionuclide, wherein the radionuclide is chelated to the chelator to produce a composition with a formula M-L-C-R. 0 137. The kit of any one of claims 133-136, wherein the radionuclide is selected from Ac- 225, Cu-64, Ga-68, Lu-177, Pb-212, In-111, Cu-67, La-132, La-135, Ce-134, F-18, I- 131, I-124, Pb-203, Th-232, Bi-123, Sm-153, Ra-225, Tb-165, or At-211. 5 138. The kit of claim 137, wherein the radionuclide is Ac-225, Cu-64, Ga-68, In-111, Lu- 177, or Pb-212.

139. The kit of any one of claims 132-138, wherein if the polypeptide has an amino acid comprising any of those set forth in any one of SEQ ID NOs: 83, 85, 93, 99, 134, 138,0 145, 155, 161-176, 195, or 200 the polypeptide further comprises a linker, wherein the linker is PEG4, and a chelator, wherein the chelator is DOTA.

140. The kit of any one of claims 133-139, wherein, when present, the linker is attached to the N-terminus amino acid of the polypeptide. IPTS / 128722251.1 Page 335 of 337Docket No.: AKT-031WO 141. The kit of any one of claims 132-140, wherein the C-terminal amino acid of the polypeptide is not cysteine. 5 142. The kit of any one of claims 133-141, wherein, when present, the chelator is attached to either the polypeptide or the linker.

143. The kit of any one of claims 133-142, wherein, when present, the radionuclide is attached to the chelator. 0 144. The kit of any one of claims 133-143, wherein, when present, the radionuclide is attached to the N-terminus amino acid of the polypeptide. IPTS / 128722251.1 Page 336 of 337

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