Albumin binding proteins and methods of use

Abstract

Provided herein are albumin binding proteins and methods of making and using thereof.

Description

ALBUMIN BINDING PROTEINS AND METHODS OF USECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 633,665, filed on April 12, 2024, U.S. Provisional Patent Application No. 63 / 702,592, filed on October 2, 2024. and U.S. Provisional Patent Application No. 63 / 719,077, filed on November 11, 2024, the disclosure of each of which is hereby incorporated by reference in its entirety for all purposes.SEQUENCE LISTING

[0002] This application contains a Sequence Listing XML, which has been submitted electronically and is hereby incorporated by reference in its entirety. The XML copy of the Sequence Listing, created on April 8, 2024, is named PRG-042WO.xml, and is 207,986 bytes in size.BACKGROUND

[0003] Efficacy and convenience of administration of therapeutics depends on many factors including serum half-life. Serum half-life (t 1 / 2) of biotherapeutics can be impacted by many factors including rate and completeness of clearance through cellular recycling mechanisms. Albumin is an abundant, water-soluble protein in mammalian plasma, where, among other functions, it can act as a carrier protein and a protein to stabilize extracellular fluid volume. The circulatory half-life of albumin proteins is very long, including as compared to other serum proteins. Accordingly, albumin represents a therapeutic target to leverage for extension of halflives of molecules, e.g., therapeutic molecules.SUMMARY OF THE DISCLOSURE

[0004] The present disclosure, among other things, addresses certain unmet needs in making and using biotherapeutics. Compositions of the disclosure provide and leverage albumin binding proteins to extend length of serum-half lives of therapeutic molecules. The disclosure also provides methods of making and using such albumin binding proteins and fusions thereof.

[0005] In one aspect, the disclosure provides an albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3. wherein: (a) the CDR1 has an amino acid sequence comprising or consisting of X1FGMX5, wherein Xi can be R or S and X5 can be S or G; (b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NO: 115, wherein X51 can be I or V; X52 can be D or N; X53 can be S or G; X54 can be G or S; X56 can be A, T, V, D, or G; X57 can beD, V. or T; X59 can be R, L, or 1: Xei can be A, S. or T; X62 can be E or D; X63 can be S or T; X64 can be V or I; and (c) the CDR3 has an amino acid sequence comprising or consisting of GX99X100X101X102R, wherein X99 can be R, G, or Q; X100 can be S or G; X101 can be S, T, A, or I; and X102 can be S or T.

[0006] In one aspect, the disclosure provides an albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3, wherein: (a) the CDR1 has an amino acid sequence comprising or consisting of SEQ ID NO: 28 or 29; (b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NOs: 30-43; and (c) the CDR3 has an amino acid sequence comprising or consisting of SEQ ID NOs: 44-53.

[0007] In one aspect, the disclosure provides an albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3, wherein: (a) the CDR1 has an amino acid sequence comprising or consisting of SEQ ID NO: 188, wherein Xi can be R or S; (b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NO: 189. wherein X56 can be A or T; X63 can be S or T; X64 can be V or I; and (c) the CDR3 has an amino acid sequence comprising or consisting of SEQ ID NO: 190, wherein X99 can be R, G, or Q; and X101 can be T or A.

[0008] In one aspect, the disclosure provides an albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3. wherein: (a) the CDR1 has an amino acid sequence comprising or consisting of SEQ ID NO: 28 or 29; (b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NOs: 30, 31, or 34; and (c) the CDR3 has an amino acid sequence comprising or consisting of SEQ ID NOs: 44, 45, or 47.

[0009] In one aspect, the disclosure provides an albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3, wherein: (a) the CDR1 has an amino acid sequence comprising or consisting of SEQ ID NO: 29; (b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NO: 31; and (c) the CDR3 has an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0010] In one aspect, the disclosure provides an albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3, wherein: (a) the CDR1 has an amino acid sequence selected from the group consisting of SX32GMS. wherein X32 is F or A. and SFGX34S, wherein X34 is M or A;(b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NO: 31; and(c) the CDR3 has an amino acid sequence compnsing or consisting of SEQ ID NO: 45. In some embodiments, the CDR1 has an amino acid sequence comprising SFGMS (SEQ ID NO: 29). In some embodiments, the CDR1 has an amino acid sequence comprising SAGMS (SEQ ID NO: 178). In some embodiments, the CDR1 has an amino acid sequence comprising SFGAS (SEQ ID NO: 179).

[0011] In certain embodiments, the albumin binding protein further comprises at least one additional component (D2), linked to the albumin binding protein (DI) according to a formula, from N-to-C terminus, of: (a) D1-L-D2, or (b) D2-L-D1, wherein DI comprises the albumin binding protein provided herein; D2 comprises the at least one additional component; and L comprises a linker. In some embodiments, D2 comprises a second antigen binding protein or a non-antigen binding moiety. In some embodiments, the albumin binding protein further comprises one, two, three, four or more additional antigen-binding proteins or non-antigen binding moieties. wherein each additional antigen binding protein or non-antigen binding moiety is optionally linked to DI or another additional antigen binding protein or non- antigen binding moiety by a linker.

[0012] In some embodiments, the linker is or comprises a peptide linker. For example, in some embodiments, the linker has an amino acid sequence comprising any of those set forth in Table 6. In certain embodiments, the linker has an amino acid sequence comprising any one of SEQ ID NOs: 144-159. In certain embodiments, the linker has an amino acid sequence comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 144.

[0013] In some embodiments, D2 comprises an antigen binding protein selected from a single chain antibody or binding fragment thereof (e.g. , scFv (e.g. , a bispecific scFv), e.g. , a single heavy chain, a single light chain, a variable heavy-chain domain (e.g, a VHH), a variable light-chain domain, a variable NAR domain, a single chain polypeptide), an F(ab’), an F(ab')2 (e.g, a bi-specific F(ab’)2), an F(Ab?)3 (e.g, a tri-specific F(Ab’)3), an Fv. a DARPin. an Fc domain (e.g, an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.), a minibody, a diabody, a dAb fragment, an antibody (e.g, a monoclonal antibody), a multispecific binding protein (e.g, bispecific antibody), and combinations thereof. For example, in some embodiments, the antigen binding protein of D2 comprises a variable heavy chain domain comprising or consisting of a VHH domain. In some embodiments, D2 comprises anon-antigen binding moiety selected from a detectable tag (e.g., a His tag, a Flag tag, a fluorescent tag), and an Fc domain (e.g, an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.).

[0014] In some embodiments, the binding affinity of the albumin binding protein for albumin is stronger than about 10 pM, about 7.5 pM, about 5 pM, about 2.5 pM, about 1 pM, about 0.75 pM, about 0.5 pM, about 0.25 pM, about 0.1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM. about 4 nM, about 3 nM. about 2 nM, about 1 nM. about 0.75 nM, about 0.5 nM, about 0.25 nM. about 0.1 nM, about 0.01 nM, or about 0.001 nM. In some embodiments, the binding affinity of the albumin binding protein for albumin is stronger than about 0. 1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM, about 3 nM. about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM. about 0.25 nM, about 0.1 nM, or about 0.01 nM.

[0015] In some embodiments, the albumin binding protein binds to albumin with a KD of less than or equal to about 1 x 10-6 M at pH 6.0 or pH 7.4 as measured by surface plasmon resonance (SPR). In certain embodiments, the albumin binding protein binds to albumin with a KD of less than or equal to about 1 x 10-7 M at pH 6.0 or pH 7.4 as measured by SPR. In certain embodiments, the albumin binding protein binds to albumin with a KD of less than or equal to about 1 x 10-8 M at pH 6.0 or pH 7.4 as measured by SPR. In certain embodiments, the albumin binding protein binds to albumin with a KD of less than or equal to about 1 x 10-9 M at pH 6.0 or pH 7.4 as measured by SPR.

[0016] In some embodiments, the albumin binding protein has been humanized.

[0017] In certain embodiments, the binding affinity of the albumin binding protein for albumin is stronger at pH 6.0 than at pH 7.4. In certain embodiments, the binding affinity of the albumin binding protein for albumin is stronger at pH 7.4 than at pH 6.0. In certain embodiments, the binding affinity of the albumin binding protein for albumin is substantially unchanged between pH 6.0 and pH 7.4.

[0018] In one aspect, the disclosure provides an albumin binding protein comprising a VHH domain comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 1-27, 108-114, and 172-175.

[0019] In one aspect, the disclosure provides an albumin binding protein comprising a VHH domain comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 108-114 and 173-175.

[0020] In one aspect, the disclosure provides an albumin binding protein consisting of an amino acid sequence selected from the group consisting of SEQ ID NOs: 108-114 and 173-175.

[0021] In one aspect, the disclosure provides a pharmaceutical composition comprising (a) a fusion protein comprising two domains, DI, and D2, wherein: (i) DI comprises an albumin binding protein provided herein; and (ii) D2 comprises at least one additional componentcomprising an antigen binding protein or a non-antigen binding moiety; and (b) a pharmaceutically acceptable excipient.

[0022] In some embodiments, the fusion protein further comprises one, two, three, four or more additional antigen binding proteins or non-antigen binding moieties.

[0023] In some embodiments, the DI and the D2 domains of the fusion protein are linked by a linker according to a formula, from N-to-C terminus, of (a) D1-L-D2 or (b) D2-L-D1, wherein L is the linker.

[0024] In certain embodiments, the linker is or comprises a peptide linker. For example, in some embodiments, the linker has an amino acid sequence comprising any one of SEQ ID NOs: 144-159. In some embodiments, the linker has an amino acid sequence comprising, consisting essentially of, or consisting of SEQ ID NO: 144.

[0025] In some embodiments, D2 comprises a second antigen binding fragment selected from a single chain antibody or binding fragment thereof (e.g, scFv (e.g, a bispecific scFv), e.g. , a single heavy chain, a single light chain, a variable heavy -chain domain (e.g.. a VHH). a variable light-chain domain, a variable NAR domain, a single chain polypeptide), an F(ab’), an F(ab’)2 (e.g., a bi-specific F(ab’)2), an F(Ab’)3 (e.g, a tri-specific F(Ab’)3), an Fv, a DARPin, an Fc domain (an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.), a minibody, a diabody, a dAb fragment, an antibody (e.g, a monoclonal antibody), a multispecific binding protein (e.g, bispecific antibody), and combinations thereof. For example, in some embodiments, D2 comprises a variable heavy chain domain comprising or consisting of a VHH domain. In some embodiments, D2 comprises a non- antigen binding moiety selected from a detectable tag (e.g. , a His tag, a Flag tag, a fluorescent tag) and an Fc domain (e.g, an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.).

[0026] In some embodiments, a binding affinity of the albumin binding protein of DI for albumin is stronger than about 10 pM, about 7.5 pM, about 5 pM, about 2.5 pM, about 1 pM, about 0.75 pM. about 0.5 pM, about 0.25 pM. about 0. 1 pM, about 75 nM, about 50 nM. about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM, about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0.1 nM, about 0.01 nM, or about 0.001 nM. In some embodiments, the binding affinity of the albumin binding protein of DI for albumin is stronger than about 0.1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM, about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0. 1 nM, or about 0.01 nM.

[0027] In certain embodiments, the albumin binding protein of DI binds to albumin with a KD of less than or equal to about 1 x 10-7 M at pH 6.0 or pH 7.4 as measured by SPR. In certain embodiments, the albumin binding protein of DI binds to albumin with a KD of less than or equal to about 1 x 10-8 M at pH 6.0 or pH 7.4 as measured by SPR. In certain embodiments, the albumin binding protein of DI binds to albumin with a KD of less than or equal to about 1 x 10- 9 M at pH 6.0 or pH 7.4 as measured by SPR.

[0028] In some embodiments, the albumin binding protein of DI has been humanized.

[0029] In certain embodiments, the binding affinity of the albumin binding protein of DI for albumin is stronger at pH 6.0 than at pH 7.4. In certain embodiments, the binding affinity of the albumin binding protein of DI for albumin is stronger at pH 7.4 than at pH 6.0. In certain embodiments, the binding affinity of the albumin binding protein of DI for albumin is substantially unchanged between pH 6.0 and pH 7.4.

[0030] In one aspect, the disclosure provides a fusion protein comprising at least two domains according to a formula, from N-to-C terminus, of: (a) Orientation I: D1-L-D2; or (b) Orientation II: D2-L-D1 , wherein DI is the albumin binding protein provided herein; L is a linker; and D2 is an additional protein binding domain or non-antigen binding domain. In some embodiments, the albumin binding protein binds with a stronger affinity when arranged in a configuration comprising D1-L-D2 as compared to D2-L-D1 when measured by SPR. In some embodiments, the albumin binding protein binds with a stronger affinity when arranged in a configuration comprising D2-L-D1 as compared to D1-L-D2 when measured by SPR.

[0031] In some embodiments, the albumin binding affinity7of the albumin binding protein in orientation I is stronger than that of the albumin binding protein in orientation II at pH 6.0 and / or pH 7.4. In some embodiments, the albumin binding affinity of the albumin binding protein in orientation I is substantially unchanged as compared to that of the albumin binding protein in orientation II at pH 6.0 and / or pH 7.4. In some embodiments, the albumin binding affinity of the albumin binding protein in orientation II is stronger than that of the albumin binding protein in orientation I at pH 6.0 and / or pH 7.4.

[0032] In one aspect, the disclosure provides a method of generating a fusion protein comprising linking an albumin binding protein (DI) as provided herein to at least one additional component (D2), wherein when D2 is linked to D 1 it shows one or more improvements on measures of half-life.

[0033] In one aspect, the disclosure provides a method of increasing a half-life of a therapeutic molecule, the method comprising administering a fusion protein comprising: an albumin binding protein, (DI) as provided herein, linked to at least one additional component comprising or consisting of a therapeutic molecule, (D2), wherein a half-life of the therapeuticmolecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 not linked to DI .

[0034] In one aspect, the disclosure provides a method of increasing a half-life of a therapeutic molecule in a subject in need thereof, the method comprising administering an effective amount of a fusion protein comprising an albumin binding protein (DI) as provided herein, linked to at least one additional component comprising or consisting of a therapeutic molecule (D2), wherein a half-life of the therapeutic molecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 not linked to DI.

[0035] In some embodiments, the half-life of the therapeutic molecule in the fusion protein is increased by at least about 1.05-fold, 1.1-fold, 1.15-fold, 1.2-fold, 1.25-fold, 1.3-fold, 1.35- fold, 1.4-fold, 1.45-fold, 1.50-fold, 1.55-fold, 1.6-fold, 1.65-fold, 1.7-fold, 1.75-fold. 1.8-fold, 1.85-fold, 1.9-fold, 1.95-fold, 2-fold, 2.5-fold, 3-fold, 3.5-fold, 4-fold, 4.5-fold, 5-fold, 6-fold, 7- fold, 8-fold, 9-fold, 10-fold, 15-fold, 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 75-fold, 100- fold, 200-fold, 250-fold, 300-fold, 350-fold, 400-fold, 450-fold. 500-fold, 550-fold, 600-fold, 650-fold, 700-fold. 750-fold. 1,000-fold, 1,250-fold, 1,500-fold, 1,750-fold, 2,000-fold, 2,250- fold, 2,500-fold, 2,750-fold, 3,000-fold, 3,250-fold, 3,500-fold, 3,750-fold, 4,000-fold, 4,250- fold, 4,500-fold, 4,750-fold, 5,000-fold or greater as compared to the therapeutic molecule not in the fusion protein.

[0036] In some embodiments, the effective amount is lower when the subject is administered the fusion protein as compared to D2 not linked to DI.

[0037] In some embodiments, the frequency of administration is reduced when the subject is administered the fusion protein as compared to D2 not linked to DI.

[0038] In one aspect, the disclosure provides a method of treating a subject in need thereof, the method comprising administering an effective amount of a fusion protein comprising an albumin binding protein, DI, as provided herein linked to at least one additional component, D2, comprising or consisting of a therapeutic molecule, wherein a half-life of the therapeutic molecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 not linked to DI.

[0039] In one aspect, the disclosure provides a method of increasing a half-life of a therapeutic molecule, the method comprising linking an albumin binding protein, DI, as provided herein, to at least one additional component, D2, comprising or consisting of a therapeutic molecule, wherein the half-life of the therapeutic molecule after the linking is greater than before the linking.

[0040] In certain embodiments, administration of the fusion protein is subcutaneous. In certain embodiments, administration of the albumin binding protein is intravenous.

[0041] In one aspect, the disclosure provides a method of treating a disease or disorder in a patient in need thereof, the method comprising subcutaneously or intravenously administering to the patient an effective amount of a pharmaceutical composition as provided herein.

[0042] In some embodiments, DI and D2 are linked by a linker that is or comprises a peptide linker. For example, in some embodiments, the linker has an amino acid sequence comprising any one of SEQ ID NOs: 144-159. In some embodiments, the linker has an amino acid sequence comprising, consisting essentially of, or consisting of SEQ ID NO: 144.

[0043] In one aspect, the disclosure provides a polynucleotide encoding an albumin binding protein as provided herein.

[0044] In one aspect, the disclosure provides a polynucleotide encoding a fusion protein comprising, from N-to-C terminus, D1-L-D2, wherein DI comprises or consists of an albumin binding protein as provided herein; L is a linker; and D2 is at least one additional component comprising or consisting of a therapeutic molecule or a detectable molecule.

[0045] In one aspect, the disclosure provides a polynucleotide encoding a fusion protein comprising, from N-to-C terminus, D2-L-D1, wherein DI comprises or consists of an albumin binding protein as provided herein; L is a linker; and D2 is at least one additional component comprising or consisting of a therapeutic molecule or a detectable molecule.

[0046] In some embodiments, the linker is or comprises a peptide linker. For example, in some embodiments, the linker has an amino acid sequence comprising any one of SEQ ID NOs: 144-159. In certain embodiments, the linker has an amino acid sequence comprising, consisting essentially of, or consisting of SEQ ID NO: 144.

[0047] In some embodiments, the therapeutic molecule is selected from a single chain antibody or binding fragment thereof (e.g., scFv (e.g.. a bispecific scFv), e.g, a single heavy chain, a single light chain, a variable heavy-chain domain (e.g. , a VHH), a variable light-chain domain, a variable NAR domain, a single chain polypeptide), an F(ab’), an F(ab’)2 (e.g., a bispecific F(ab’)2), an F(Ab')3 (e.g., a tri-specific F(Ab’)3), an Fv, a DARPin, an Fc domain (e.g.. an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.), a minibody, a diabody, a dAb fragment, a multispecific binding protein (e.g., bispecific antibody), and combinations thereof. In some embodiments, the at least one additional component comprises or consists of detectable molecule selected from a his tag, a flag tag, a fluorescent tag, and / or an Fc domain (e.g., an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.).

[0048] In one aspect, the disclosure provides a host cell comprising a polynucleotide as provided herein.DETAILED DESCRIPTIONDefinitions

[0049] To facilitate an understanding of the present disclosure, a number of terms and phrases are defined below.

[0050] The terms “a” and “an” as used herein mean “one or more7’ and include the plural unless the context is inappropriate.

[0051] As used herein, all numerical values or numerical ranges include whole integers within or encompassing such ranges and fractions of the values or the integers within or encompassing ranges unless the context clearly indicates otherwise. Thus, for example, reference to a range of 90-100%, includes 91%, 92%, 93%, 94%, 95%, 95%, 96%, 97%, etc., as well as 91.1%, 91.2%, 91.3%, 91.4%, 91.5%, etc., 92.1%, 92.2%, 92.3%, 92.4%, 92.5%, etc., and so forth. In another example, reference to a range of 1-5,000-fold includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20-fold, etc., as well as 1.1, 1.2, 1.3, 1.4, 1.5-fold, e / c., 2.1, 2.2. 2.3, 2.4, 2.5-fold, etc., and so forth.

[0052] As used herein, the terms “about,” “approximately,” and “comparable to,” when used herein in reference to a value, refer to a value that is similar to the referenced value in the context of that referenced value. In general, those skilled in the art, familiar with the context, will appreciate the relevant degree of variance encompassed by "about," “approximately.” and “comparable to” in that context. For example, in some embodiments, the terms "about," “approximately,” and “comparable to” may encompass a range of values that within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less of the referred value.

[0053] “Percent (%) identity” refers to the extent to which two sequences (nucleotide or amino acid) have the same residue at the same positions in an alignment. For example, “an amino acid sequence is X% identical to SEQ ID NO: Y” refers to % identity of the amino acid sequence to SEQ ID NO: Y and is elaborated as X% of residues in the amino acid sequence are identical to the residues of sequence disclosed in SEQ ID NO: Y. Generally, computer programs are employed for such calculations. Exemplary programs that compare and align pairs of sequences include ALIGN (Myers and Miller, 1988), FASTA (Pearson and Lipman, 1988; Pearson, 1990) and gapped BLAST (Altschul et al., 1997), BLASTP, BLAS TN, or GCG (Devereux et al., 1984).

[0054] Throughout the description, where compositions are described as having, including, or comprising specific components, or where processes and methods are described as having, including, or comprising specific steps, it is contemplated that, additionally, there are compositions of the present disclosure that consist essentially of, or consist of, the recitedcomponents, and that there are processes and methods according to the present disclosure that consist essentially of, or consist of, the recited processing steps.

[0055] As a general matter, compositions specifying a percentage are by weight unless otherwise specified. Further, if a variable is not accompanied by a definition, then the previous definition of the variable controls.

[0056] As used herein, unless otherwise indicated, the term '‘antibody” is understood to mean an intact antibody (e.g. , an intact monoclonal antibody), or a fragment thereof, an antigenbinding fragment (e.g., an antigen-binding fragment of a monoclonal antibody, e.g., a VHH or nanobody), or an Fc domain (e.g., an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.) that has been modified, engineered, or chemically conjugated. In some embodiments, an antibody is a polypeptide whose amino acid sequence includes immunoglobulins and fragments thereof which specifically bind to a designated antigen, or fragments thereof. Antibodies in accordance with the present disclosure may be of any type (e.g.. IgA, IgD, IgE, IgG, or IgM) or subtype (e.g., IgAl, IgA2. IgGl, IgG2, IgG3, or IgG4). Those of ordinary skill in the art will appreciate that a characteristic sequence or portion of an antibody may include amino acids found in one or more regions of an antibody (e.g., variable region, hypervariable region, constant region, heavy chain, light chain, and combinations thereof). Moreover, those of ordinary skill in the art will appreciate that a characteristic sequence or portion of an antibody may include one or more polypeptide chains, and may include sequence elements found in the same polypeptide chain or in different polypeptide chains. Antibodies can refer to multimeric proteins that contain four polypeptide chains. Two of the polypeptide chains are called immunoglobulin heavy chains (H chains), and two of the polypeptide chains are called immunoglobulin light chains (L chains). The immunoglobulin heavy and light chains are connected by an interchain disulfide bond. The immunoglobulin heavy chains are connected by interchain disulfide bonds. A light chain consists of one variable region (VL) and one constant region (CL). The heavy chain consists of one variable region (VH) and at least three constant regions (CHI, CH2 and CH3). The variable regions determine the binding specificity of the antibody. Antibodies can also refer to and encompass variable regions, e.g., VHH or VNAR regions such as from heavy-chain only antibodies, including those naturally produced by certain species (e.g., camelids or sharks, respectively, etc.) and those engineered therefrom (e.g., humanized VHH proteins). Each variable region contains three hypervanable regions known as complementarity determining regions (CDRs) flanked by four relatively conserved regions known as framew ork regions (FRs). The term “CDR” denotes a complementarity determining region as defined by at least one manner of identification to one of skill in the art. In some embodiments, CDRs can be defined inaccordance with any known numbering schemes or definitions including, e.g, Chothia (see Chothia and Lesk, J Mol Biol, 1987, 196:901-917), the Kabat (see Kabat et al., 1992, Sequences of Proteins of Immunological Interest, DIANE Publishing: 2719; see also Kabat et al., 1991 , Sequences of Proteins of Immunological Interest, 5th Ed.. United States Public Health Service, National Institutes of Health, Bethesda and Edelman et al. 1969, Proc. Natl. Acad. Sci. USA 63(l):78-85, as set forth in Kabat 1991 for refence to "EU index as set forth in Kabat" or "EU index of Kabat" and "position . . . according to the EU index as set forth in Kabat," and grammatical variants thereof refer to the residue numbering system based on the human IgGl EU antibody description therein), a combination of Kabat and Chothia or modified Chothia (“AbM”) (see Whitelegg & Rees, Protein Eng. 2000, 13:819-824; Whitelegg & Rees, Methods Mol Biol. 2004, 248:51-91), IMGT (see Lefranc, (1999) The Immunologist, 7, 132-136), and / or the Contact (see MacCallum et al., J. Mol. Biol. 1996, 262:732-745). The extent of the FRs and CDRs has been defined (Kabat, E.A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91- 3242; and Chothia, C. et al. (1987) J. Mol. Biol. 196:901 -917). The three CDRs, referred to as CDR1, CDR2, and CDR3, contribute to the antibody binding specificity. CDR sequences provided herein are according to Kabat, but one of ordinary skill in the art will understand how to adapt such CDRs to other definitions and / or numbering schemes (e.g, Chothia, AbM, IMGT, etc.). Naturally occurring antibodies have been used as starting material for engineered antibodies, such as chimeric antibodies and humanized antibodies. Examples of antibody-based antigen-binding fragments include Fab, Fab’, (Fab’)2, Fv, single chain (e.g., scFv, VHH, etc.) or single-domain antibodies (sdAbs, comprising, e.g., at least one VHH domain and an Fc region), VHH-containing polypeptides (polypeptides comprising at least one VHH domain), minibodies, and diabodies, and portions and / or binding fragments of any of the foregoing. Examples of antibodies that have been modified or engineered include chimeric antibodies, humanized antibodies, antibodies of various species (e.g., camelid (llama), shark, human, cynomolgus monkey, mouse, rat, etc.), and multispecific antibodies (e.g, bispecific antibodies); such modified or engineered antibodies are also understood to encompass fragments thereof including, for example, single chain antibodies or fragments. Antibodies may be produced as fusion proteins and / or conjugated to another entity. An example of an antibody fusion protein is an antibody linked to another binding entity (e.g, another antibody fragment) or a tag (e.g, a his tag) via a linker. An example of a chemically conjugated antibody is an antibody conjugated to a toxin moiety.

[0057] The terms “variable domain’" and “variable region” are used interchangeably and refer to the portions of the antibody or immunoglobulin domains that exhibit variability in theirsequence and that are involved in determining the specificity and binding affinity of a particular antibody. Variability is not evenly distributed throughout the variable domains of antibodies; it is concentrated in sub-domains of each of the heavy and light chain variable regions. These subdomains are called “hypervariable regions” or “complementarity determining regions” (CDRs). The more conserved (z.e., non-hypervariable) portions of the variable domains are called the “framework” regions (FRM or FR) and provide a scaffold for the six CDRs in three-dimensional space to form an antigen-binding surface.

[0058] As used herein, the term “VHH” or “VHH domain” or “nanobody ” refers to an antigen binding protein of a heavy-chain-only single chain or single domain antibody, such as from a camelid (z.e., heavy chain only) antibody. In some embodiments, a VHH comprises three CDRs and four framework regions, designated FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4. In some embodiments, a VHH may be truncated at the N-terminus or C-terminus such that it comprises only a partial FR1 and / or FR4, or lacks one or both of those framework regions, so long as the VHH substantially maintains antigen binding and specificity. A “single domain antibody” or “sdAb” refers to a binding protein (e.g„ antibody, fragment thereof) comprising at least one monomeric domain, such as a VHH domain, devoid of a light chain, and, optionally, an Fc region. In some embodiments, an sdAb is a dimer of two polypeptides wherein each polypeptide comprises at least one VHH domain and an Fc region. In some such embodiments, the at least one VHH domain can be linked to the N-terminus of the Fc region. In certain embodiments, the at least one VHH domain can be linked to the C-terminus of the Fc region. As used herein, the terms “single domain antibody” and “sdAb” encompass polypeptides that comprise multiple tandem VHH domains, such as a polypeptide having the structure VHHi- VHH2-FC or VHH1-VHH2-VHH3-FC, wherein the VHH domains may be the same or different and, in some embodiments, may be linked by a linker.

[0059] The terms “antigen-binding domain” as well as “antigen-binding fragment” or “antibody fragment” as used herein refers to a binding protein that can be an antibody as defined herein or portion thereof (e. , of an antibody, e.g, of an intact antibody such as a monoclonal antibody, e.g.. of a heavy chain only antibody, etc.) sufficient to bind to a given antigen. The portion of the antibody can include e.g., a fragment of an intact antibody, e.g., a heavy chain only antibody, such as, e.g., a VHH, etc. In some embodiments, if the antigen-binding domain is, for example, a fragment that is a component of a larger protein such as an intact antibody (e.g.. a monoclonal antibody), and the intact antibody has a function, the domain or fragment also retains that function. In some embodiments, an antigen-binding fragment comprises the variable region of the antibody (e.g., of a monoclonal antibody, e.g., of a heavy chain only antibody, etc. ).

[0060] An antigen-binding protein comprises or consists of an antigen-binding domain. In some embodiments, an antigen binding domain of a conventional antibody comprises three heavy chain CDRs and three light chain CDRs. Thus, in some embodiments, an antigen binding domain comprises a heavy chain variable region comprising CDR1-FR2-CDR2-FR3-CDR3, and any portions of FR1 and / or FR4 required to maintain binding to antigen, and a light chain variable region comprising CDR1-FR2-CDR2-FR3-CDR3, and any portions of FR1 and / or FR4 required to maintain binding to antigen. In some embodiments, an antigen-binding domain comprises a heavy chain variable region and a light chain variable region. Nonlimiting such antigen-binding domains include Fabs and scFvs. In some embodiments, an antigen-binding protein or antigen binding domain compnses or consists of a VHH domain. In some such embodiments, the binding protein or binding domain comprises three CDRs, e.g., of a VHH domain, e.g., CDR1, CDR2, and CDR3. Thus, in some embodiments, an antigen binding domain of, for example, a binding protein comprising or consisting of a VHH may comprise, e.g., CDR1-FR2-CDR2-FR3-CDR3, and any portions of FR1 and / or FR4 required to maintain binding to antigen, or, alternatively FR1 -CDR1 -FR2-CDR2-FR3-CDR3-FR4, and fragments and binding portions thereof.

[0061] A “non-antigen” binding domain or moiety refers to a component such as a detectable label (e.g., a flag tag. ahis tag. a fluorescent tag) or another protein component (e.g., an Fc domain, e.g., an Fc or fragment thereof, a modified Fc, etc.) that itself is not intended to bind to a target (e.g., an antigen, an epitope of an antigen, e.g., a target antigen such as albumin), but can be used, for example, to detect, identify, isolate, separate an entity (e.g., an antigen binding protein or domain such as an albumin binding protein) to which the non-antigen binding domain is linked (e.g., fused, such as through a linker).

[0062] As used herein, a “target antigen” refers to an antigen that is intended to be bound by a molecule of the disclosure. For example, a target antigen for the albumin binding proteins herein is albumin (e.g., mammalian albumin, e.g., human albumin). A target antigen for a second antigen binding domain may include a target that a therapeutic molecule is designed to bind to, such that two target antigens exist in an albumin protein fusion described herein, albumin and a target of an additional component of the albumin fusion (e.g., a target of a therapeutic molecule, which molecule is linked to an albumin binding protein).

[0063] As used herein, the term “epitope” is an antigenic determinant that interacts with a specific antigen binding site in the variable region of an antibody molecule, known as the paratope, and which is comprised of the six complementary-determining regions of the antibody or the three complementary-determining regions of a single-domain antibody (VHH). A single antigen may have more than one epitope. Epitopes may be conformational or linear. Aconformational epitope is comprised of spatially juxtaposed amino acids from different segments of a linear polypeptide chain. A linear epitope is comprised of adjacent amino acid residues in a polypeptide chain.

[0064] As used herein, the term ‘‘humanized,’' when used in reference to an antibody, refers to a form of a non-human (e.g., murine) antibody that is chimeric. A “humanized antibody” contains minimal sequences derived from non-human immunoglobulin. Typically, humanized antibodies are human immunoglobulins (recipient or acceptor antibody) in which hypervariable region residues of the recipient are replaced by hypervariable region residues from a non-human species (donor antibody) such as mouse, rat. rabbit or nonhuman primate having a desired specificity, affinity, and capacity. In some instances, Fv framework region (FR) residues of the human immunoglobulin are replaced by corresponding non-human residues. Furthermore, humanized antibodies may comprise residues which are not found in the recipient antibody or in the donor antibody. These modifications are made to further refine antibody performance such as binding affinity. Generally, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the hypervariable loops correspond to those of a non-human immunoglobulin and all or substantially all of the framework regions are those of a human immunoglobulin sequence although the framework regions may include one or more amino acid substitutions that improve binding affinity. In some embodiments, no more than six amino acid substitutions in the heavy chain and no more than three amino acid substitutions are used in the light chain in the framework region. The humanized antibody optionally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin.

[0065] As used herein, the term “isolated” (e.g.. with reference to a nucleic acid molecule (polynucleotide), an amino acid molecule (polypeptide), etc.) is a molecule that is identified and separated from at least one contaminant molecule with which it is ordinarily associated in the natural source of the molecule. An isolated molecule is other than in the form or setting in which it is found in nature. For example, isolated nucleic acid molecules can be distinguished from nucleic acid molecules as they exists in natural cells.

[0066] The terms “recipient”, “individual”, “subject”, “host”, and “patient”, are used interchangeably herein and in some embodiments, refer to any mammalian subject for whom diagnosis, treatment, or therapy is desired, particularly humans. “Mammal” for purposes of treatment refers to any animal classified as a mammal, including humans, domestic and farm animals, and laboratory, zoo, sports, or pet animals, such as dogs, horses, cats, cows, sheep, goats, pigs, mice, rats, rabbits, guinea pigs, monkeys, etc. In some embodiments, the mammal is human. None of these terms require the supervision of medical personnel.

[0067] As used herein, the term “effective amount” or “therapeutically effective amount” may be used interchangeably and refer to the amount (e.g, of a composition, e.g., as provided herein) effective, at dosages and for periods of time necessary', to achieve a desired result, e.g., a desired beneficial result, a desired therapeutic result. An effective amount can be administered in one or more administrations, applications or dosages and is not intended to be limited to a particular formulation or administration route. A therapeutically effective amount may vary according to factors such as the type of disease (e.g, disease state, age, sex, and / or weight of the individual, and the ability' of an antibody (or pharmaceutical composition thereof) to elicit a desired response in the individual. An effective amount may also be an amount for which any toxic or detrimental effects of the antibody or pharmaceutical composition thereof are outweighed by therapeutically beneficial effects.

[0066] As used herein, the term “treating” includes any effect, e.g., lessening, reducing, modulating, preventing, ameliorating or eliminating, that results in the stabilization, improvement, or prevention of a condition, disease, disorder, and the like, or ameliorating a symptom thereof. To “treat” a condition or “treatment” of a condition is an approach for obtaining beneficial or desired results, such as clinical results. Beneficial or desired results can include, but are not limited to, alleviation or amelioration of one or more symptoms or conditions; diminishment of extent of disease, disorder, or condition; stabilized (i.e., not worsening) state of disease, disorder, or condition; preventing spread of disease, disorder, or condition; delay or slowing the progress of the disease, disorder, or condition; amelioration or palliation of the disease, disorder, or condition; and remission (whether partial or total), whether detectable or undetectable. “Palliating” a disease, disorder, or condition means that the extent and / or undesirable clinical manifestations of the disease, disorder, or condition are lessened and / or time course of the progression is slowed or lengthened, as compared to the extent or time course in the absence of treatment. A “therapeutic molecule” refers to a molecule that can be used to treat, as described herein.

[0067] As used herein, the term “pharmaceutical composition” refers to the combination of an active agent with a carrier, inert or active, making the composition especially suitable for diagnostic or therapeutic use in vivo or ex vivo.

[0068] As used herein, the term “pharmaceutically acceptable carrier” refers to any of the standard pharmaceutical carriers, such as a phosphate buffered saline solution, water, emulsions (e.g, such as an oil / water or water / oil emulsions), and various types of wetting agents. The compositions also can include stabilizers and preservatives. For examples of carriers, stabilizers and adjuvants, see e.g., Martin, Remington's Pharmaceutical Sciences, 15th Ed., Mack Publ. Co., Easton, PA (1975).Albumin Binding Proteins

[0069] The disclosure provides albumin binding proteins, and methods, making and using such binding proteins. Albumin represents a target that can be leveraged to address an unmet need in the field of therapeutics. Serum albumin is a water soluble blood protein produced by the liver. It is considered the most abundant mammalian blood protein. Albumin is known to naturally function as a carrier protein in the blood, and is considered to have a very long halflife. Accordingly, and without wishing to be bound by theory, this disclosure contemplates that, in some embodiments, linking (e.g, fusing, e.g., through a linker) a therapeutic molecule to serum albumin using albumin binding VHHs provided herein represents an advance in improving half-life of therapeutics. VHHs are single antigen binding domains that originate from heavy chain antibodies of other species such as camelids and sharks. These variable domain binding fragments are small and stable and, as such, may be better positioned to penetrate tissues or physiological barriers than larger binding proteins (e.g., monoclonal antibodies).

[0070] Albumin binding proteins provided herein comprise a VHH binding domain. Such albumin proteins were discovered by immunizing llamas with human serum albumin. Resulting binding proteins were isolated, purified, and sequenced as provided and described herein (see exemplary sequences of VHH and CDR proteins at least in TABLES 1-3). Selected llamagenerated albumin binding proteins were subsequently humanized (see. e.g, TABLES 4-5 for exemplary amino acid sequences of exemplary humanized binding proteins).

[0071] Among other things, provided herein are albumin binding proteins comprising an antigen binding domain of a heavy chain variable region (VHH). Provided herein, in certain embodiments, are albumin binding proteins comprising a VHH domain selected from any of SEQ ID NOs: 1-27 as set forth in TABLE 1.

[0072] In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 1. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 2. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 3. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 4. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 5. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 6. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an aminoacid sequence of SEQ ID NO: 7. In some embodiments, the albumin binding protein compnses or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 8. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 9. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 10. In some embodiments, an amino acid sequence of SEQ ID NO: 11. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 12. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 13. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 14. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 15. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 16. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 17. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 18. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 19. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 20. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 21. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 22. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 23. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 24. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 25. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 26. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 27.

[0073] In some embodiments, an albumin binding protein of the disclosure may have one or more amino acid modifications to one or more regions (e.g., CDRs, FR regions) relative to a protein comprising or consisting of the amino acid sequences disclosed in TABLE 1. For example, in some embodiments, the VHH may have one, two, three, four, five, six. seven, eight, nine, ten or more substitutions in one or more framework regions (independently or cumulatively across framework regions). For example, in some embodiments, the VHH may have one, two, three, four, five, six, seven, eight, nine, ten or more substitutions (e.g., amino acid substitutions, deletions, etc.) in one or more framework regions (independently or cumulatively across framework regions). In certain embodiments, the VHH may have no more than four, three, two, or one substitutions in one or more framework regions (independently or cumulatively). In some embodiments, the VHH may have no more than four, three, two, or one substitutions in any given framework region. In some embodiments, the VHH may have no more than four, three, two, or one substitutions across all framew ork regions relative to any of those disclosed in TABLE 1

[0074] In some embodiments, the albumin binding protein comprises a heavy chain variable region (VHH) comprising a CDR1, CDR2, and CDR3 as listed in TABLE 2.

[0075] In certain embodiments, the disclosure provides a VHH domain comprising (a) a CDR1 comprising or consisting of an amino acid sequence represented by XiFGMXs, where Xi can be R or S: and Xs can be S or G; (b) a CDR2 comprising or consisting of an amino acid sequence represented by AX51X52X53X54GX56X57TX59YX61X62X63X64KG, where X51 can be I or V; X52 can be D or N; X53 can be S or G; X54 can be G or S; X56 can be A, T, V, D, or G; X57 can be D, V, or T; X59 can be R, L. or I; Xei can be A, S, or T; X62 can be E or D; Xes can be S or T; and X64 can be V or I; and (c) a CDR3 comprising or consisting of an amino acid sequence represented by GX99X100X101X102R, where X99 can be R, G, or Q; X100 can be S or G; X101 can be S, T, A, or I; and X102 can be S or T.

[0076] In certain embodiments, an albumin binding protein comprises: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3, wherein: (a) the CDR1 comprises or consists of an amino acid sequence of X1FGMX5, wherein Xi can be R or S and Xs can be S or G; (b) the CDR2 comprises or consists of an amino acid sequence of SEQ ID NO: 115, wherein X51 can be I or V; X52 can be D or N; X53 can be S or G; X54 can be G or S; X56 can be A, T, V, D, or G; X57 can be D, V, or T; X59 can be R, L, or I; Xei can be A, S, or T; X62 can be E or D; X63 can be S or T; X64 can be V or I; and (c) the CDR3 comprises or consists of an amino acid sequence of GX99X100X101X102R, wherein X99 can be R, G, or Q; X100 can be S or G; X101 can be S, T, A, or I; and X102 can be S or T.

[0077] In certain embodiments, the VHH domain comprises (a) a CDR1 having an amino acid sequence according to SEQ ID NOs: 28, 29, or 162, (b) a CDR2 having an amino acid sequence according to any one of SEQ ID NOs: 30-43, and (c) a CDR3 having an amino acid sequence according to any one of SEQ ID NOs: 44-53.

[0078] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence comprising or consisting of SEQ ID NO: 28, 29, or 162, (b) a CDR2 having an amino acid sequence comprising or consisting of any of SEQ ID NOs: 30-43, and (c) a CDR3 having an amino acid sequence comprising or consisting any of SEQ ID NOs: 44-53.

[0079] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 28, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 30, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 44.

[0080] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 30, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 45.

[0081] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 30, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 46.

[0082] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 31, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 45.

[0083] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 32, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 45.

[0084] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 33, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 44.

[0085] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) aCDR2 having an amino acid sequence of SEQ ID NO: 30, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 44.

[0086] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 30, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 47.

[0087] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 34, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 44.

[0088] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 35, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 44.

[0089] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 31, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 45.

[0090] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 36, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 44.

[0091] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 37, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 44.

[0092] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 38, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 45.

[0093] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 32, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 48.

[0094] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 34, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 44.

[0095] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 39, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 45.

[0096] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 33, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 49.

[0097] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 40, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 49.

[0098] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 41, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 50.

[0099] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 42, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 51.

[0100] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 162, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 42. and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 51.

[0101] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) a CDR2 having an amino acid sequence of SEQ ID NO: 43, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 52.

[0102] In some embodiments, the albumin binding protein comprises a VHH domain comprising or consisting of (a) a CDR1 having an amino acid sequence of SEQ ID NO: 29, (b) aCDR2 having an amino acid sequence of SEQ ID NO: 34, and (c) a CDR3 having an amino acid sequence of SEQ ID NO: 53.

[0103] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of any of SEQ ID NOs: 1-27. having three CDR sequences therein, wherein: (a) CDR1 can comprise or consist of an amino acid sequence represented by X1FGMX5, where Xi can be R or S; and Xs can be S or G; (b) CDR2 can comprise or consist of an amino acid sequence represented by AX51X52X53X54GX56X57TX59YX61X62X63X64KG, where X51 can be I or V; X52 can be D or N; X53 can be S or G; X54 can be G or S; X56 can be A, T, V, D, or G; X57 can be D, V, or T; X59 can be R, L, or I; Xei can be A, S, or T; X62 can be E or D; X63 can be S or T; and X64 can be V or I; and (c) CDR3 can comprise or consist of an amino acid sequence represented by GX99X100X101X102R, where X99 can be R, G, or Q; X100 can be S or G; X101 can be S, T, A, or I; and X102 can be S or T.

[0104] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of any of SEQ ID NOs: 1 -27, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 28, 29, or 162, (b) CDR2 can have an amino acid sequence comprising or consisting of any of SEQ ID NOs: 30-43. and (c) CDR3 can have an amino acid sequence comprising or consisting of any of SEQ ID NOs: 44-53.

[0105] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 1, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 28, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 30, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0106] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 2, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 30, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0107] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 3, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQID NO: 30. and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 46.

[0108] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 4, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0109] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 5, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 30, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0110] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 6, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 32, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.[OHl] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 7, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 33, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0112] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 8, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 30. and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0113] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 9, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consistingof SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 30, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 47.

[0114] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 10. having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 34, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0115] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 11, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 35. and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0116] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 12, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0117] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 13. having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 36, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0118] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 14, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 37, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0119] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 15, having three CDRsequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 30, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0120] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 16, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 30. and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0121] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 17, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31 , and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0122] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 18, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 38, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0123] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 19, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 32. and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 48.

[0124] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 20, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 34, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 44.

[0125] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 21, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 39. and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0126] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 22, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 33, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 49.

[0127] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 23. having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 40, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 49.

[0128] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 24, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 41. and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 50.

[0129] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 25, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 162, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 42, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 51.

[0130] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 26, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQID NO: 43. and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 52.

[0131] In some embodiments, the albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 27, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 34, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 53.

[0132] Amino acid sequences of exemplary VHH domains of exemplary albumin binding proteins are provided in TABLE 1. Consensus sequences of CDRs of exemplary VHH domains along with allowable amino acid residues therein is provided in TABLE 2. CDRs of exemplary VHH domains are provided in TABLE 3.TABLE 1. Exemplary Llama VHH Albumin Binding ProteinsTABLE 2. Consensus Sequences of Exemplary Llama VHH CDRsTABLE 3. Exemplary Llama VHH CDRs1Residue numbers are based on N-to-C terminal residue positions in VHH domains with reference to those of SEQ ID NOs: 1-27.Humanization

[0133] Albumin binding proteins of the disclosure may be humanized. In some embodiments, humanization can be performed by, but not limited to, methods known to those of ordinary skill in the art. In some embodiments, humanization is performed by CDRH grafting using VH modeling. In some such embodiments, VH modeling is achieved using AlphaFold 2. As provided herein, humanized albumin binding protein VHH domains were generated using llama-derived albumin binding protein VHH domains of TABLE 1, having CDRs as set forth in TABLE 2 and TABLE 3

[0134] Exemplary humanized VHH albumin binding proteins are set forth in TABLES 4- 5E. In some embodiments, humanized proteins of the present disclosure bind to human serum albumin with a stronger binding affinity than non-humanized binding proteins. Without wishing to be bound by theory, the disclosure contemplates that humanization of the sequences of TABLE 1 can, in some embodiments, confer one or more advantages including but not limited to stronger and / or more specific binding to human proteins and less immunogenicity in a human when administered for therapeutic uses.

[0135] Non-human derived (e.g., llama) albumin binding proteins can be humanized using one or more techniques for humanization. For example, albumin binding proteins having an amino acid sequence comprising or consisting of those set forth in TABLE 1 can be humanized. Humanization can be performed by suitable methods including, but not limited to, those known to a person of ordinary skill in the art. For example, in some embodiments, AlphaFold2 can be used to predict a VH model. In certain embodiments, homology can be leveraged to select a VH germline. Features taken into account for humanization can include homology and developability. For example, homology of human germline to parental sequence, especially framework regions, can be evaluated. Other considerations can include germline usage rate in existing humanized or human therapeutic monoclonal antibodies, and distribution of V region gene segments in the natural human antibody repertoire. In some embodiments, based on homology, VH germline usage rate in exemplary therapeutic monoclonal antibodies, and distributions of the VH gene in natural / endogenous human antibody repertoire, a germline can be selected for VH CDR grafting and humanization.

[0136] Exemplary7humanized VHH albumin binding proteins are provided in TABLE 4. CDRs of the humanized VHHs are provided in TABLES 5A - 5E.

[0137] Among other things, provided herein are humanized albumin binding proteins comprising or consisting of an antigen binding domain, w hich domain is, or is part of the variable region of a heavy chain only antibody (VHH). Provided herein, in certain embodiments,are albumin binding proteins comprising or consisting of a VHH domain selected from any of SEQ ID NOs: 108-114 and 173-175 as set forth in TABLE 4.

[0138] In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 108. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 109. In some embodiments, the albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 110. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 111. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 112. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 113. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 114. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 173. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 174. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising or consisting of an amino acid sequence of SEQ ID NO: 175.

[0139] In certain embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1). a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein, as set forth in any one of SEQ ID NOs: 108-114 and 173-175. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1). a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 108. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1), a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 109. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity7determining region 1 (CDR1), a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ IDNO: 110. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1), a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 111. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1), a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 112. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1). a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 113. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1), a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 114. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1), a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 173. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1), a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 174. In some embodiments, the humanized albumin binding protein comprises or consists of a VHH domain comprising each of a complementarity determining region 1 (CDR1). a complementarity determining region 2 (CDR2), and a complementarity determining region 3 (CDR3) therein as set forth in SEQ ID NO: 175.

[0140] In some embodiments, an albumin binding protein of the present disclosure may have one or more amino acid modifications to one or more regions (e.g., CDRs, FR regions) relative to a protein comprising or consisting of any of the amino acid sequences disclosed in TABLE 4. For example, in some embodiments, the VHH may have one, two, three, four, five, six, seven, eight, nine, ten or more substitutions (e.g., amino acid substitutions, deletions, etc.) in one or more framework regions (independently or cumulatively across framework regions). In certain embodiments, the VHH may have no more than four, three, two, or one substitutions in one or more framework regions (independently or cumulatively). In some embodiments, the VHH may have no more than four, three, two, or one substitutions in any given framework region. In some embodiments, the VHH may have no more than four, three, two, or one substitutions across all framework regions relative to any of those disclosed in TABLE 4. In certain embodiments, theVHH has one or more additional amino acids (e.g, relative to the amino acid sequences set forth in any one of SEQ ID NOs: 108-114 and 173-174) on its N- and / or C-terminus. For example, in some embodiments, a VHH may have a C-terminal extension comprising at least one, two, three, or four amino acids. In certain embodiments, the VHH has an additional C-terminal residue (e.g., alanine) relative to the C-terminal residue corresponding to the sequences of any one of SEQ ID NOs: 108-114 and 173-174. By way of a non-limiting example, in certain embodiments, the amino acid sequence of such a VHH is set forth in SEQ ID NO: 175.

[0141] In some embodiments, the albumin binding protein comprises a humanized heavy' chain variable region (VHH) comprising a CDR1. a CDR2, and a CDR3 such as listed in TABLES 5A-5E. In certain embodiments, the VHH may have no more than four, three, two, or one substitutions in one or more CDRs (independently or cumulatively). In certain embodiments, the CDRs of the VHH (CDR1, CDR2, and CDR3) have sequences that can each independently differ by at most two amino acids from the CDRs provided herein. In some embodiments, the CDRs have sequences that are identical to those of the CDRs of any VHH, except for one or two amino acid substitutions total across all three CDRs.

[0142] In one aspect, the disclosure provides an albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3, wherein: (a) the CDR1 has an amino acid sequence selected from SX32GMS (SEQ ID NO: 176), wherein X32 is F or A, and SFGX34S (SEQ ID NO: 177), wherein X34 is M or A; (b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NO: 31; and (c) the CDR3 has an amino acid sequence comprising or consisting of SEQ ID NO: 45. In some embodiments, the CDR1 has an amino acid sequence comprising SFGMS (SEQ ID NO: 29). In some embodiments, the CDR1 has an amino acid sequence comprising SAGMS (SEQ ID NO: 178). In some embodiments, the CDR1 has an amino acid sequence comprising SFGAS (SEQ ID NO: 179). In some embodiments, the CDR1 has an amino acid sequence comprising SAGAS (SEQ ID NO: 180).

[0143] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 108, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence selected from SX32GX34S, wherein X32 is F or A, and X34 is M or A, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0144] In certain embodiments, CDR1 has an amino acid sequence comprising SFGMS (SEQ ID NO: 29), SAGMS (SEQ ID NO: 178), SFGAS (SEQ ID NO: 179), or SAGAS (SEQ ID NO: 180). In some embodiments. CDR1 has an amino acid sequence comprising SFGMS. Insome embodiments, CDR1 has an amino acid sequence compnsing SAGMS (SEQ ID NO: 178). In certain embodiments, CDR1 has an amino acid sequence comprising SFGAS (SEQ ID NO:179). In certain embodiments, CDR1 has an amino acid sequence comprising SAGAS (SEQ ID NO: 180).

[0145] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SX32GMS (SEQ ID NO:176), wherein X32 is F or A, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0146] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SFGX34S (SEQ ID NO:177). wherein X34 is M or A. (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0147] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising three CDR sequences therein, wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of any one of SFGMS (SEQ ID NO: 29), SAGMS (SEQ ID NO: 178), SFGAS (SEQ ID NO: 179) and SAGAS (SEQ ID NO:180) (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0148] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SFGMS (SEQ ID NO: 29) (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0149] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 173, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SAGMS (SEQ ID NO: 178) (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0150] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 174, havingthree CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SFGAS (SEQ ID NO: 179) (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0151] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 175, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SAGAS (SEQ ID NO: 180) (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0152] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 108, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29. (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0153] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 109, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0154] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 110, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29. (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0155] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 111, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0156] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 112, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29. (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0157] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 113, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0158] In some embodiments, the humanized albumin binding protein comprises a VHH domain having an amino acid sequence comprising or consisting of SEQ ID NO: 114, having three CDR sequences therein wherein: (a) CDR1 can have an amino acid sequence comprising or consisting of SEQ ID NO: 29, (b) CDR2 can have an amino acid sequence comprising or consisting of SEQ ID NO: 31, and (c) CDR3 can have an amino acid sequence comprising or consisting of SEQ ID NO: 45.

[0159] Amino acid sequences of exemplary humanized VHH albumin binding proteins are provided in TABLE 4. CDRs of exemplary humanized VHH albumin binding proteins and VHH albumin binding control are provided in TABLES 5A-5E.

[0160] In some embodiments, an albumin binding protein comprises a heavy chain variable region (VHH) that comprises an amino acid sequence at least 85% (e.g., at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or 100%) identical to the VHH domain of an albumin binding protein disclosed in TABLE 1 or TABLE 4

[0161] In some embodiments, an albumin binding protein comprises a heavy chain variable region (VHH) that comprises an amino acid sequence at least 85% (e.g., at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or 100%) identical to any one of SEQ ID NO: 108-114 and 173-175. In some such embodiments, the CDRs of any such protein are identical to any of those set forth in TABLES 3 and 5A-5E.

[0162] In some embodiments, the CDRs may correspond to those in TABLES 2. 3, and 5A- 5E and but according to other CDR definitions and / or numbering schemes (e.g., Chothia, IMGT, etc. as described herein).

[0163] In some embodiments, an albumin binding protein comprises a heavy chain variable region (VHH) that comprises an amino acid sequence at least 85% (e.g, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or 100%) identical to any one of SEQ ID NO: 108-114, provided that the heavy chain variable region (VHH) comprises CDR1 of SEQ ID NO: 29, CDR2 of SEQ ID NO: 31, and CDR3 of SEQ ID NO: 45.

[0164] In some embodiments, an albumin binding protein comprises a heavy chain variable region (VHH) that comprises an amino acid sequence at least 85% (e.g., at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%. at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or 100%) identical SEQ ID NO: 173, provided that the heavy chain variable region (VHH) comprises CDR1 of SEQ ID NO: 178, CDR2 of SEQ ID NO: 31, and CDR3 of SEQ ID NO: 45.

[0165] In some embodiments, an albumin binding protein comprises a heavy chain variable region (VHH) that comprises an amino acid sequence at least 85% (e.g, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or 100%) identical to SEQ ID NO: 174, provided that the heavy chain variable region (VHH) comprises CDR1 of SEQ ID NO: 179. CDR2 of SEQ ID NO: 31. and CDR3 of SEQ ID NO: 45.

[0166] In some embodiments, an albumin binding protein comprises a heavy chain variable region (VHH) that comprises an amino acid sequence at least 85% (e.g., at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, or 100%) identical to SEQ ID NO: 175, provided that the heavy chain variable region (VHH) comprises CDR1 of SEQ ID NO: 178, CDR2 of SEQ ID NO: 31, and CDR3 of SEQ ID NO: 45.

[0167] In some embodiments, an albumin binding protein comprises a heavy chain variable region (VHH) that comprises an amino acid sequence at least 85% (e.g, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least99.9%. or 100%) identical to any one of SEQ ID NOs: 173-175, provided that the heavy chain variable region (VHH) comprises CDR1 of SEQ ID NO: 180, CDR2 of SEQ ID NO: 31, and CDR3 of SEQ ID NO: 45.TABLE 4. Exemplary Humanized VHH Albumin Binding ProteinsTABLE 5A. Consensus Sequences of Exemplary Humanized VHH Albumin Binding Protein Kabat CDRs2Residue numbers are based on N-to-C terminal residue positions in VHH domains with reference to those of SEQ ID NOs: 130-140.TABLE 5B. Kabat CDRs of Exemplary Humanized VHH Albumin Binding Proteins & VHH Albumin Binding ControlTABLE 5C. Chothia CDRs of Exemplary Humanized VHH Albumin Binding Proteins & VHH Albumin Binding ControlTABLE 5D. IM GT CDRs of Exemplary Humanized VHH Albumin Binding Proteins & VHH Albumin Binding ControlTABLE 5E. North CDRs of Exemplary Humanized VHH Albumin Binding Proteins & VHH Albumin Binding Control

[0149] In some embodiments, the disclosure provides a nucleic acid molecule encoding an albumin binding protein provided herein. In some embodiments, a host cell comprises the polynucleotide encoding the albumin binding protein. Polynucleotides encoding desired albumin binding proteins can be incorporated (ligated) into expression vectors, which can be introduced into host cells through conventional transfection or transformation techniques. Exemplary host cells are E. coll cells. Chinese hamster ovary (CHO) cells, human embryonic kidney 293 (HEK 293) cells, HeLa cells, baby hamster kidney (BHK) cells, monkey kidney7cells (COS), human hepatocellular carcinoma cells (e.g, Hep G2), and myeloma cells.

[0150] In some embodiments, an albumin binding protein of the disclosure binds to albumin with a binding affinity stronger than about 10 pM. about 7.5 pM, about 5 pM, about 2.5 pM. about 1 pM, about 0.75 pM, about 0.5 pM, about 0.25 pM, about 0.1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM, about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0.1 nM, about 0.01 nM, or about 0.001 nM.

[0151] In some embodiments, the binding affinity for albumin is stronger than about 0. 1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM, about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0.1 nM, or about 0.01 nM.

[0152] In some embodiments, the albumin binding protein binds to albumin with a KD of less than or equal to about l x 10'6M, 1 x 10'7M, 1 x 10'8M, 1 x 10'9M, or less at pH 6.0 or pH 7.4 as measured by surface plasmon resonance (SPR).

[0153] In some embodiments, the binding affinity of the albumin binding protein for albumin is stronger at pH 6.0 than at pH 7.4. In some embodiments, the binding affinity is stronger at pH 7.4 than at pH 6.0. In some embodiments, the binding affinity is substantially unchanged at pH 6.0 as compared to pH 7.4.

[0154] In some embodiments, an albumin binding protein of the disclosure binds to serum albumin from multiple species (e.g, human, cynomolgus monkey, mouse, rat, etc.). In some embodiments, an albumin binding protein of the disclosure has been humanized and binds to human serum albumin at a greater affinity than to serum albumin from, e.g., monkey, mouse, rat, etc.

[0155] In some embodiments, the albumin binding proteins are characterized by a half-life of at least about 3, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98 or more days. In some embodiments, the half-life is in a range of about 3 days to about 98 days, about 7 days to about 91 days, about 14 days to about 84 days, about 21 days to about 77 days, about 28 days to about 70 days, about 35 days to about 63 days, about 42 days to about 56 days, about 3 days to about 42 days, about 7 days to about 49 days, about 14 days to about 56 days, about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or more days, etc. In some embodiments, the half-life is in a range of about 14 days to about 56 days. In some embodiments, the half-life is at least about 84 days. In some embodiments, the half-life is at least about 56 days. In some embodiments, the half life is at least about 28 days. In some embodiments, the half-life is at least about 14 days. In some embodiments, the half-life is at least about 7 days.

[0156] Methods of measuring half-life are known in the art. In some embodiments, the half- life is measured in a mammal. In some embodiments, the mammal is a non-human primate. In some embodiments, the mammal is a human. In some embodiments, the half-life is measured in a human to whom the composition has been previously administered. In some embodiments, the half-life is measured following intravenous administration. In some embodiments, the half-life is measured following subcutaneous administration.

[0157] In some embodiments, an albumin binding protein of the disclosure is formulated into a composition comprising one or more additional components (e.g, as a fusion protein), examples of which are provided and described herein.Fusion Proteins

[0158] Provided herein are fusion proteins comprising an albumin binding protein of the disclosure (“DI”) and at least one additional component (“D2”). In some embodiments, DI and D2 are linked by a linker (L).

[0159] In some embodiments, the fusion proteins comprising albumin binding proteins provided herein are characterized by an extended half-life (e.g, serum half-life) as compared to a comparator, such as a therapeutic molecule that is not linked to an albumin binding protein as provided herein and / or, e.g., a reference albumin binding protein (e.g., as in TABLE 5 and / or SEQ ID NO: 125 or 134).

[0160] Fusions of the disclosure may be generated in different arrangements. For example, in some embodiments, a fusion protein can have, in N-to-C terminal direction, an arrangement (Orientation I), comprising D1-L-D2, wherein DI comprises or consists of an albumin binding protein of the disclosure (comprising or consisting of a VHH), L is a linker; and D2 compnses or consists of at least one additional component.

[0161] In certain embodiments, a fusion protein can have, in N-to-C terminal direction, an arrangement (Orientation II), comprising D2-L-D1, wherein DI comprises or consists of an albumin binding protein of the disclosure (comprising or consisting of a VHH); L is a linker; and D2 comprises or consists of at least one additional component.

[0162] In certain embodiments, the at least one additional component (D2) can comprise or consist of a second antigen binding protein or domain and / or a non-antigen binding moiety. In some embodiments, the second antigen binding protein or domain can be a therapeutic molecule. A therapeutic molecule may be an antigen binding molecule or a non-antigen binding moiety, and can be intended for use to achieve a particular effect (e.g, to treat) when contacting a cell and / or when administered to a subject in need thereof.

[0163] In some embodiments, the second antigen binding protein may comprise or consist of a single chain antibody or binding fragment thereof (e.g, scFv (e.g, a bispecific scFv), e.g, a single heavy chain, a single light chain, a vanable heavy-cham domain (e.g, a VHH), a variable light-chain domain, a variable NAR domain, a single chain polypeptide), an F(ab’), an F(ab’)2 (e.g., a bi-specific F(ab’)2), an F(Ab’)3 (e.g., a tri-specific F(Ab’)3), an Fv, a DARPin, an Fc domain (e.g, an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.), a minibody, a diabody, a dAb fragment, an antibody (e.g., a monoclonal antibody), a multispecific binding protein (e.g., bispecific antibody), and combinations thereof. In some embodiments, the second antigen binding protein (D2) may be a variable heavy chain domain comprising or consisting of a VHH domain. In some such embodiments, the VHH domain may be the same or different as the albumin binding protein of DI. In some embodiments, D2 may comprise or consist of a non-antigen binding moiety selected from a detectable tag such as a His tag, a Flag tag, a fluorescent tag, an Fc domain (e.g., an Fc fragment, etc.), etc. In some embodiments, a D2 comprising or consisting of an Fc fragment does not bind an Fc antigen (e.g., an Fc receptor, etc.). In some embodiments, the Fc fragment mayonly have a small set of components (e.g., not all CH regions, partial CH regions, etc. ) as compared to a wild-type Fc and / or may have one or more substitutions as compared to a wildtype Fc or fragment thereof.

[0164] In certain embodiments, an albumin binding protein fusion may further comprise one, two, three, four or more additional antigen binding proteins or non-antigen binding moieties (e.g., Dl-L-Dn or Dn-Dl-L-), wherein n is selected from 1, 2, 3, 4, or more and wherein each Dndomain may be the same or different from another Dndomain in the same fusion.

[0165] In some embodiments, a fusion protein of the disclosure binds to albumin with a binding affinity stronger than about 10 pM. about 7.5 pM, about 5 pM. about 2.5 pM, about 1 pM, about 0.75 pM, about 0.5 pM, about 0.25 pM, about 0. 1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM, about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0.1 nM, about 0.01 nM, or about 0.001 nM.

[0166] In some embodiments, the binding affinity of the fusion protein is stronger than about 0.1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM, about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0.1 nM, or about 0.01 nM.

[0167] In some embodiments, the fusion protein binds to albumin with a KD of less than or equal to about 1 x 10‘6M, 1 x 10‘7M, 1 x 10‘8M, 1 x 10‘9M, or less at pH 6.0 or pH 7.4 as measured by surface plasmon resonance (SPR).

[0168] In some embodiments, the fusion protein binds (e.g., to albumin) with a stronger affinity when arranged in a configuration comprising D1-L-D2 as compared to D2-L-D1 when measured by SPR. In some embodiments, the fusion protein binds (e.g.. to albumin) with a stronger affinity when arranged in a configuration comprising D2-L-D1 as compared to D1-L-D2 when measured by SPR.

[0169] In some embodiments, the binding affinity of the fusion protein for albumin is stronger at pH 6.0 than at pH 7.4. In some embodiments, the binding affinity is stronger at pH 7.4 than at pH 6.0. In some embodiments, the binding affinity is substantially unchanged at pH 6.0 as compared to pH 7.4.

[0170] In some embodiments, the albumin binding affinity7of the fusion protein in orientation I is stronger than that of the fusion protein in orientation II at pH 6.0 and / or pH 7.4. In some embodiments, the albumin binding affinity of the fusion protein in orientation I is substantially unchanged as compared to that of the albumin binding protein in orientation II at pH 6.0 and / or pH 7.4. In some embodiments, the albumin binding affinity7of the fusion protein in orientation II is stronger than that of the fusion protein in orientation I at pH 6.0 and / or pH 7.4.

[0171] In some embodiments, the fusion proteins are characterized by a half-life of at least about 3, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98 or more days. In some embodiments, the half-life is in a range of about 3 days to about 98 days, about 7 days to about 91 days, about 14 days to about 84 days, about 21 days to about 77 days, about 28 days to about 70 days, about 35 days to about 63 days, about 42 days to about 56 days, about 3 days to about 42 days, about 7 days to about 49 days, about 14 days to about 56 days, about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or more days, etc. In some embodiments, the half-life is in a range of about 14 days to about 56 days. In some embodiments, the half-life is at least about 84 days. In some embodiments, the half-life is at least about 56 days. In some embodiments, the half life is at least about 28 days. In some embodiments, the half-life is at least about 14 days. In some embodiments, the half-life is at least about 7 days. In some embodiments, the half-life of the fusion proteins comprising DI and D2 is increased when DI is linked to D2 as compared to the half-life of D2 alone (not linked to DI).

[0172] In some embodiments, the half-life of D2 in the fusion protein is increased at least about 1.05-fold, 1.1 -fold, 1.15-fold, 1.2-fold, 1.25-fold, 1.3-fold, 1.35-fold, 1.4-fold, 1.45-fold, 1.50-fold, 1.55-fold, 1.6-fold, 1.65-fold, 1.7-fold, 1.75-fold, 1.8-fold, 1.85-fold, 1.9-fold, 1.95- fold, 2-fold, 2.5-fold. 3-fold, 3.5-fold, 4-fold, 4.5-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10- fold, 15-fold. 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 75-fold, 100-fold, 200-fold, 250-fold. 300-fold, 350-fold, 400-fold, 450-fold, 500-fold, 550-fold, 600-fold, 650-fold, 700-fold, 750- fold, 1,000-fold, 1,250-fold, 1,500-fold, 1,750-fold, 2,000-fold, 2,250-fold, 2,500-fold, 2,750- fold, 3,000-fold, 3,250-fold, 3,500-fold, 3,750-fold, 4,000-fold, 4,250-fold, 4,500-fold, 4,750- fold, 5,000-fold or greater as compared to D2 alone (not in the fusion protein with DI).

[0173] Methods of measuring half-life include, but are not limited to. those well-known in the art. In some embodiments, the half-life is measured in a mammal. In some embodiments, the mammal is a non-human primate. In some embodiments, the mammal is a human. In some embodiments, the half-life is measured in a human to whom the composition has been previously administered. In some embodiments, the half-life is measured following intravenous administration. In some embodiments, the half-life is measured following subcutaneous administration.

[0174] In some embodiments, the fusion proteins comprising albumin binding proteins provided herein have a half-life that is at least 10% longer than a comparator e.g., the at least one additional component (D2) not linked to an albumin binding protein, e.g.. an antibody, e.g.. an antibody fragment, e.g.. a reference albumin binding protein and / or fusion thereof, etc.). In some embodiments, the comparator comprises the same complementarity' determining regions and variable regions but different FR regions as the albumin binding protein (DI) in the fusion. Insome embodiments, the comparator comprises the D2 alone (not fused to DI). In some embodiments, the half-life of the albumin binding proteins described herein is at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 100% longer than the half-life of the comparator. In some embodiments, the half-life of the albumin binding proteins described herein is longer than the half-life of the comparator by at least about 1.05-fold, 1.1-fold, 1.15-fold, 1.2-fold, 1.25-fold, 1.3-fold, 1.35-fold, 1.4-fold, 1.45-fold, 1.50-fold, 1.55-fold, 1.6-fold, 1.65-fold, 1.7-fold, 1.75- fold, 1.8-fold, 1.85-fold, 1.9-fold, 1.95-fold, 2-fold, 2.5-fold, 3-fold, 3.5-fold. 4-fold, 4.5-fold, 5- fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 15-fold, 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 75-fold, 100-fold, 200-fold, 250-fold, 300-fold, 350-fold, 400-fold, 450-fold, 500-fold, 550-fold, 600-fold, 650-fold, 700-fold, 750-fold, 1,000-fold, 1,250-fold, 1,500-fold, 1,750-fold, 2,000- fold, 2,250-fold, 2,500-fold, 2,750-fold, 3.000-fold, 3.250-fold, 3,500-fold, 3,750-fold, 4,000- fold, 4.250-fold, 4.500-fold, 4.750-fold, 5.000-fold or greater as compared to D2 alone (not linked to DI).

[0175] In some embodiments, the disclosure provides a polynucleotide encoding a fusion protein comprising an albumin binding protein provided herein, a linker, and at least one additional component. In some embodiments, a host cell comprises the polynucleotide encoding the fusion. In some embodiments, more than one host cell comprises, independently, separate components encoding the albumin binding protein (DI) and the at least one additional component (D2), which may be chemically conjugated to one another after each component is expressed. Polynucleotides encoding desired albumin binding proteins or fusions thereof can be incorporated (ligated) into expression vectors, which can be introduced into host cells through conventional transfection or transformation techniques. Exemplary host cells are E. coll cells, Chinese hamster ovary' (CHO) cells, human embryonic kidney 293 (HEK 293) cells, HeLa cells, baby hamster kidney (BHK) cells, monkey kidney cells (COS), human hepatocellular carcinoma cells (e.g, Hep G2), and myeloma cells.

[0176] In certain embodiments, the disclosure provides a polynucleotide encoding a fusion protein comprising, from N-to-C terminus: (a) D1-L-D2; or (b) D2-L-D1, wherein, in each instance, DI can comprise or consist of an albumin binding protein provided herein; L is a linker; and D2 can comprise or consist of at least one additional component. In some embodiments, the at least one additional component can comprise or consist of a therapeutic molecule or a detectable molecule. In some embodiments, the linker is selected from those provided herein (e.g, TABLE 6).

[0177] Exemplary fusion proteins demonstrating linking of at least one additional component to an albumin binding protein as provided herein are provided in Example 2,TABLES 7 and 8 and Example 5, TABLES 11, 12, and 13Linkers

[0178] Compositions provided herein can include one or more linkers. For example, in some embodiments, one or more components of a composition may be covalently bonded (e.g., conjugated, joined, attached, cross-linked) or otherwise associated (e.g., non-covalently bound) to one another by one or more linkers, thus, in each embodiment, “linking” the components. In some embodiments, an albumin binding protein, DI, (e.g, a VHH as provided herein) may be linked to one additional components, D2, (e.g., an antigen binding protein or non-antigen binding protein) via a linker.

[0179] In certain embodiments, a composition provided herein may comprise one or more linkers (L). For example, a composition comprising an albumin binding protein (DI) may be linked to at least one additional component (D2) (e.g., an antigen binding protein, a non-antigen binding moiety7, efc.). In some embodiments, the linking is by a linker (L). In certain embodiments, the linker links the C-terminus of DI to the N-terminus of D2 (D1-L-D2). In certain embodiments, the linker links the C-terminus of D2 to the N-terminus of DI (D2-L-D1). As is understood to those of skill in the art, such compositions may be produced as genetic fusion proteins or as fusions that are conjugated together separately (e.g., after expression of each of DI and D2).

[0180] In certain embodiments, linkers can be non-covalent. For example, a non-covalent linker can refer to the linking of two entities (e.g., DI and / or D2 as provided herein, e.g., proteins, fragments thereof, non-antigen binding moieties, e.g., molecules, e.g., chemical moieties, etc.) by anon-covalent interaction or bond. By way of non-limiting example, non- covalent interactions or bonds can include hydrogen bonds, electrostatic bonds or interactions, halogen bonds, pi stacking, and van der Waals interactions.

[0181] In certain embodiments, linkers may be synthetic compound linkers such as, for example, chemical cross-linking agents. In some embodiments, a chemical cross-linking agent is selected from N-hydroxy succinimide (NHS), disuccinimidylsuberate (DSS), bis(sulfosuccinimidyl)suberate (BS3), dithiobis(succinimidylpropionate) (DSP), dithiobis(sulfosuccinimidylpropionate) (DTSSP), ethyleneglycol bis(succinimidylsuccinate) (EGS), ethyleneglycol bis(sulfosuccinimidylsuccinate) (sulfo-EGS), disuccinimidyl tartrate (DST), disulfosuccinimidyl tartrate (sulfo-DST), bis[2- (succinimidooxycarbonyloxy)ethyl]sulfone (BSOCOES), and bis[2-(sulfosuccinimidooxycarbonyloxy)ethyl] sulfone (sulfo-BSOCOES). Given context, other appropriate chemical crosslinking agents will be known to those of skill in the art.

[0182] In certain embodiments, linkers may be peptide linkers (e.g., comprising amino acid residues and peptide bonds). In some embodiments, a peptide linker includes one or more peptide bonds. In some embodiments, a peptide linker includes one or more disulfide bonds. In some embodiments, a peptide linker results in one or more disulfide bonds (e.g.. a peptide linker may comprise a cysteine residue which may pair with another cysteine residue outside of the linker that links to form a disulfide bond).

[0183] In some embodiments, the peptide linker comprises a flexible peptide linker. In some embodiments, the peptide linker comprises a rigid peptide linker. In some embodiments, the peptide linker comprises a cleavable peptide linker. In some embodiments, peptide linkers can be part of a fusion molecule or fusion protein, including, for example, the exemplary fusion proteins provided herein. Fusion (e.g., of two components) can refer to linking of two proteins (e.g., a protein, protein fragment, polypeptide) by a peptide bond or a peptide linker such that the two components (e.g., DI and / or D2 as provided herein, proteins, fragments thereof, non-antigen binding moieties, etc.) are fused. For example, in some embodiments, an albumin binding protein as provided herein is fused to at least one additional component by a peptide linker, such as exemplary peptide linkers provided in TABLE 6.

[0184] In certain embodiments, tw o proteins can be directly and contiguously fused together by a peptide bond. In some embodiments, two proteins can be indirectly and non-contiguously fused through a peptide linker. In some embodiments, one protein is fused to a peptide linker by a peptide bond at a first position, and a second protein is fused to a peptide linker by a peptide bond at a second position. In some embodiments the linker (e.g., linker subunit, such as, for example GGGGS (SEQ ID NO: 144)) is repeated once. In some embodiments the linker is repeated more than once (e.g, GGGGSGGGGS (SEQ ID NO: 147)).

[0185] In some embodiments, a peptide linker can be a single amino acid residue or greater in length. In some embodiments, the peptide linker has at least one amino acid residue. In some embodiments, the linker has 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or more amino acid residues in length. In some embodiments, the linker has 2, 3, 4, 5, 6. 7, 8, 9, or 10 amino acids in length.

[0186] In some embodiments, the linker comprises at least 5 to about 50 amino acids. In some embodiments, the linker comprises about 5 to about 50 amino acids, about 5 to about 45 amino acids, about 5 to about 40 amino acids, about 5 to about 35 amino acids, about 5 to about 30 amino acids, about 5 to about 25 amino acids, about 5 to about 20 amino acids, about 5 to about 15 amino acids, about 5 to about 10 amino acids, about 10 to about 50 amino acids, about15 to about 50 amino acids, about 20 to about 50 amino acids, about 25 to about 50 amino acids, about 30 to about 50 amino acids, about 35 to about 50 amino acids, about 40 to about 50 amino acids, or about 45 to about 50 amino acids.

[0187] In some embodiments, the linker comprises a sequence according to any set forth inTABLE 6

[0188] In some embodiments, the linker comprises a sequence according to any one of SEQ ID NOs: 144-159.

[0189] In some embodiments, the linker comprises a sequence selected from (GS)n, (G2S)n, (G3S)n. (G4S)n, and (G)n, and wherein n is an integer from 2 to 20. In some embodiments, n is an integer from 2 to 18, from 2 to 16, from 2 to 14, from 2 to 12, from 2 to 10, from 2 to 8, from 2 to 6, from 2 to 4, from 4 to 20, from 6 to 20, from 8 to 20, from 10 to 20, from 12 to 20, from 14 to 20, from 16 to 20, or from 18 to 20.

[0190] In some embodiments, the linker comprises a sequence selected from the group consisting of (GS)n, (G2S)n, (G3S)n. (G4S)n. and (G)n. and wherein n is an integer from 2 to 20. In some embodiments, n is an integer from 2 to 18, from 2 to 16, from 2 to 14, from 2 to 12, from 2 to 10, from 2 to 8, from 2 to 6, from 2 to 4, from 4 to 20, from 6 to 20, from 8 to 20, from 10 to 20, from 12 to 20, from 14 to 20, from 16 to 20, or from 18 to 20.

[0191] In some embodiments, the linker comprises a sequence of GGGGG (SEQ ID NO: 154). In some embodiments, the linker comprises a sequence consisting of (GGGGG)n, and wherein n is an integer from 2 to 6.

[0192] In some embodiments, the linker comprises a sequence selected from GGSGGD (SEQ ID NO: 151) or GGSGGE (SEQ ID NO: 152). In some embodiments, the linker comprises a sequence selected from the group consisting of (GGSGGD )n or (GGSGGE)n. and wherein n is an integer from 2 to 6.

[0193] In some embodiments, the linker comprises a sequence selected from the group consisting of GGGSGSGGGGS (SEQ ID NO: 157) and GGGGGPGGGGP (SEQ ID NO: 154). In some embodiments, the linker comprises a sequence selected from the group consisting of (GGGSGSGGGGS)n and (GGGGGPGGGGP)n, and wherein n is an integer from 1 to 3.

[0194] In some embodiments, the linker comprises a sequence selected from the group consisting of (GX)n, (GGX)n, (GGGX)n, (GGGGX)n, and (GzX)n, wherein z is between 1 and 20, and wherein n is at least 8. In some embodiments, z is between 2 and 18, 2 and 16, 2 and 14, 2 and 12, 2 and 10, 2 and 8, 2 and 6, 2 and 4, 4 and 20, 6 and 20, 8 and 20, 10 and 20, 12 and 20, 14 and 20, 16 and 20, or 18 and 20. In some embodiments, X is serine, aspartic acid, glutamic acid, threonine, alanine, or proline.

[0195] For example, in some embodiments, a linker may include a senes of residues (e.g, alanine residues) alone or in addition to another linker (e.g., a G4S linker). In some such embodiments, a linker comprises a sequence of GGGGSGGGSAAA (SEQ ID NO: 159).

[0196] In some embodiments, the linker is a G4S (SEQ ID NO: 144) linker. In some embodiments, the linker is a G4S multimer, with 2, 3. 4, 5, or more repeats of SEQ ID NO: 144. For example, in some embodiments, a linker comprises a peptide linker selected from GSGGGGS (SEQ ID NO: 146), GGGGSGGGGS ((G4S)2; SEQ ID NO: 147), GGGGSGGGGSGGGGS ((G4S)3; SEQ ID NO: 148), GGGGSGGGGS GGGGSGGGGS ((G4S)4, SEQ ID NO: 149), GGGGSGGGGS GGGGSGGGGSGGGGS ((G4S)5, SEQ ID NO: 150), and combinations thereof. In some embodiments, a linker comprises a peptide linker selected from GG, GGG, GGS, GGGS (SEQ ID NO: 153), GSGGS (SEQ ID NO: 145), GGGGSSA (SEQ ID NO: 151), GSGGGGSGGGGS (SEQ ID NO: 152) and combinations thereof.TABLE 6. Exemplary Linker SequencesPharmaceutical Compositions

[0197] The present disclosure also features pharmaceutical compositions that contain a therapeutically effective amount of the albumin binding proteins or fusions thereof as provided herein. The composition can be formulated for use in a variety of drug delivery systems. One or more physiologically acceptable excipients or carriers can also be included in the composition for proper formulation. Suitable formulations for use in the present disclosure are found in Remington's Pharmaceutical Sciences, Mack Publishing Company, Philadelphia, Pa., 17th ed., 1985. For a brief review of methods for drug delivery, see, e.g., Langer (Science 249: 1527-1533, 1990).

[0198] A pharmaceutical composition in accordance with the disclosure may comprise an albumin binding protein as provided herein or fusion protein comprising two domains, DI and D2, wherein DI comprises or consists of an albumin binding protein of the disclosure and D2 comprises or consists of at least one additional component. In some embodiments, the at least one additional component comprises or consists of an antigen binding protein or a non-antigen binding moiety. In certain embodiments, DI and D2 are linked by a linker (L) in an orientation (N-to-C terminus) of D1-L-D2 or D2-L-D1. In some embodiments, a fusion protein may further comprise additional components, in addition to D2, wherein each additional component may be the same or different from D2 and may be linked to one or more components through a linker (e.g.. as provided herein, e.g., as in TABLE 6, etc.).

[0199] In some embodiments, a pharmaceutical composition may contain formulation materials for modifying, maintaining or preserving, for example, the pH, osmolarity, viscosity, clarity, color, isotonicity, odor, sterility, stability, rate of dissolution or release, adsorption or penetration of the composition. In such embodiments, suitable formulation materials include, but are not limited to, amino acids (such as glycine, glutamine, asparagine, arginine or lysine); antimicrobials; antioxidants (such as ascorbic acid, sodium sulfite or sodium hydrogen-sulfite); buffers (such as borate, bicarbonate, Tris-HCl, citrates, phosphates or other organic acids); bulking agents (such as mannitol or glycine); chelating agents (such as ethylenediamine tetraacetic acid (EDTA)); complexing agents (such as caffeine, polyvinylpyrrolidone, betacyclodextrin or hydroxypropyl-beta-cyclodextrin); fillers; monosaccharides; disaccharides; and other carbohydrates (such as glucose, mannose or dextrins); proteins (such as serum albumin, gelatin or immunoglobulins); coloring, flavoring and diluting agents; emulsifying agents; hydrophilic polymers (such as polyvinylpyrrolidone); low molecular weight polypeptides; saltforming counterions (such as sodium); preservatives (such as benzalkonium chloride, benzoic acid, salicylic acid, thimerosal, phenethyl alcohol, methylparaben, propylparaben, chlorhexidine, sorbic acid or hydrogen peroxide); solvents (such as glycerin, propylene glycol or polyethyleneglycol); sugar alcohols (such as mannitol or sorbitol); suspending agents; surfactants or wetting agents (such as pluronics, PEG, sorbitan esters, polysorbates such as polysorbate 20, polysorbate, triton, tromethamine, lecithin, cholesterol, tyloxapal); stability enhancing agents (such as sucrose or sorbitol); tonicity enhancing agents (such as alkali metal halides, preferably sodium or potassium chloride, mannitol sorbitol); delivery vehicles; diluents; excipients and / or pharmaceutical adjuvants (see, Remington ’s Pharmaceutical Sciences, 18th ed. (Mack Publishing Company, 1990)).

[0200] In some embodiments, a pharmaceutical composition is citrate-free.

[0201] In some embodiments, a pharmaceutical composition may contain nanoparticles, e.g.. polymeric nanoparticles, liposomes, or micelles.

[0202] In some embodiments, a pharmaceutical composition may contain a sustained- or controlled-delivery formulation. Techniques for formulating sustained- or con troll ed-delivery means, such as liposome carriers, bio-erodible microparticles or porous beads and depot injections, are also known to those skilled in the art. Sustained-release preparations may include. e.g., porous polymeric microparticles or semipermeable polymer matrices in the form of shaped articles, e.g., films, or microcapsules. Sustained release matrices may include polyesters, hydrogels, polylactides, copolymers of L-glutamic acid and gamma ethyl-L-glutamate, poly (2- hydroxyethyl-inethacrylate), ethylene vinyl acetate, or poly-D(-)-3-hydroxybutyric acid. Sustained release compositions may also include liposomes that can be prepared by any of several methods known in the art.

[0203] Pharmaceutical compositions containing an albumin binding protein or fusion thereof as provided herein can be presented in a dosage unit form and can be prepared by any suitable method. A pharmaceutical composition should be formulated to be compatible with its intended route of administration. Examples of routes of administration are intravenous (IV), intradermal, inhalation, transdermal, topical, transmucosal, intrathecal and rectal administration. In some embodiments, the albumin binding protein disclosed herein is administered intravenously or subcutaneously. In some embodiments, the albumin binding protein or fusion thereof is administered intravenously. In some embodiments, the albumin binding protein or fusion thereof is administered subcutaneously.

[0204] Useful formulations can be prepared by methods known in the pharmaceutical art. For example, see Remington 's Pharmaceutical Sciences, 18th ed. (Mack Publishing Company. 1990). Formulation components suitable for parenteral administration include a stenle diluent such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerin, propylene glycol or other synthetic solvents; antibacterial agents such as benzyd alcohol or methyl parabens: antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as EDTA;buffers such as acetates, citrates or phosphates; and agents for the adjustment of tonicity such as sodium chloride or dextrose. In some embodiments, the formulation for parenteral administration is citrate-free.

[0205] For intravenous or subcutaneous administration, suitable carriers include physiological saline, bacteriostatic water, Cremophor ELTM (BASF, Parsippany, NJ) or phosphate buffered saline (PBS). The carrier should be stable under the conditions of manufacture and storage, and should be preserved against microorganisms. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol), and suitable mixtures thereof.

[0206] An intravenous or subcutaneous drug delivery formulation may be contained in a syringe, pen, or bag. In some embodiments, the bag is connected to a channel comprising a tube and / or a needle. In some embodiments, the formulation is a lyophilized formulation or a liquid formulation.

[0207] These compositions may be sterilized by conventional sterilization techniques, or may be sterile fdtered. The resulting aqueous solutions may be packaged for use as-is, or lyophilized, the lyophilized preparation being combined with a sterile aqueous carrier prior to administration.

[0208] A polyol, which acts as a tonicifier and may stabilize the albumin binding protein, may also be included in the formulation. The polyol is added to the formulation in an amount which may vary with respect to the desired isotonicity of the formulation. In some embodiments, the aqueous formulation is isotonic. The amount of polyol added may also be altered with respect to the molecular weight of the polyol. For example, a lower amount of a monosaccharide (e.g.. mannitol) is added, compared to a disaccharide (such as trehalose). In some embodiments, the polyol which is used in the formulation as a tonicity agent is mannitol.

[0209] A detergent or surfactant may also be added to the formulation. Exemplary detergents include nonionic detergents such as polysorbates (e.g., polysorbates 20. 80, etc.) or poloxamers (e.g., poloxamer 188). The amount of detergent added is such that it reduces aggregation of the formulated antibody and / or minimizes the formation of particulates in the formulation and / or reduces adsorption. In some embodiments, the formulation may include a surfactant which is a polysorbate. In some embodiments, the formulation may contain the detergent polysorbate 80 or Tween 80. Tween 80 is a term used to describe polyoxyethylene (20) sorbitanmonooleate (see Fiedler, Lexikon der Hifsstoffe, Editio Cantor Verlag Aulendorf, 4th edi., 1996).

[0210] In embodiments, the albumin binding protein or fusion thereof of the present disclosure is formulated as a liquid formulation. In some embodiments, the liquid formulation is prepared in combination with a sugar at stabilizing levels. In some embodiments, the liquidformulation is prepared in an aqueous carrier. In some embodiments, a stabilizer is added in an amount no greater than that which may result in a viscosity undesirable or unsuitable for intravenous administration. In some embodiments, the sugar is disaccharides, <?.g., sucrose. In some embodiments, the liquid formulation may also include one or more of a buffering agent, a surfactant, and a preservative.

[0211] In some embodiments, the pH of the liquid formulation is set by addition of a pharmaceutically acceptable acid and / or base. In some embodiments, the pharmaceutically acceptable acid is hydrochloric acid. In some embodiments, the base is sodium hydroxide.

[0212] The aqueous carrier of interest herein is one which is pharmaceutically acceptable (safe and non-toxic for administration to a human) and is useful for the preparation of a liquid formulation. Illustrative carriers include sterile water for injection (SWFI), bacteriostatic water for injection (BWFI), a pH buffered solution (e.g, phosphate-buffered saline), sterile saline solution, Ringer's solution or dextrose solution.

[0213] A preservative may be optionally added to the formulations herein to reduce bacterial action. The addition of a preservative may, for example, facilitate the production of a multi-use (multiple-dose) formulation.

[0214] The albumin binding protein or fusion thereof may be lyophilized to produce a lyophilized formulation including the proteins and a lyoprotectant. The lyoprotectant may be sugar, e.g, disaccharides. In some embodiments, the lyoprotectant is sucrose or maltose. The lyophilized formulation may also include one or more of a buffering agent, a surfactant, a bulking agent, and / or a preservative.

[0215] The amount of sucrose or maltose useful for stabilization of the lyophilized drug product may be in a weight ratio of at least 1:2 protein to sucrose or maltose. In some embodiments, the protein to sucrose or maltose weight ratio is of from 1 :2 to 1 :5. In some embodiments, the pH of the formulation, prior to lyophilization, is set by addition of a pharmaceutically acceptable acid and / or base. In some embodiments, the pharmaceutically acceptable acid is hydrochloric acid. In some embodiments, the pharmaceutically acceptable base is sodium hydroxide.Methods of Preparation and Characterization

[0216] Described herein, in certain embodiments, are methods of making and characterizing albumin binding proteins and fusions thereof.

[0217] The albumin binding proteins described above can be made using recombinant DNA technology well known to a skilled person in the art. For example, one or more isolated polynucleotides encoding the albumin binding protein can be ligated to other appropriatenucleotide sequences, including, for example, constant region coding sequences, and expression control sequences, to produce conventional gene expression constructs (z.e., expression vectors) encoding the desired albumin binding proteins. Production of defined gene constructs is within routine skill in the art.

[0218] Polynucleotides encoding desired albumin binding proteins can be incorporated (ligated) into expression vectors, which can be introduced into host cells through conventional transfection or transformation techniques. Exemplary host cells are E. coli cells, Chinese hamster ovary (CHO) cells, human embry onic kidney 293 (HEK 293) cells, HeLa cells, baby hamster kidney (BHK) cells, monkey kidney cells (COS), human hepatocellular carcinoma cells (e.g, Hep G2), and myeloma cells. Transformed host cells can be grown under conditions that permit the host cells to express the genes that encode albumin binding proteins.

[0219] Specific expression and purification conditions will vary depending upon the expression system employed. For example, if a gene is to be expressed in E. coll, it is first cloned into an expression vector by positioning the engineered gene downstream from a suitable bacterial promoter, e.g, Trp or Tac, and a prokaryotic signal sequence. The expressed protein may be secreted. The expressed protein may accumulate in refractile or inclusion bodies, which can be harvested after disruption of the cells by French press or sonication. The refractile bodies then are solubilized, and the protein may be refolded and / or cleaved by methods known in the art.

[0220] If the engineered gene is to be expressed in eukary otic host cells, e.g., CHO cells, it is first inserted into an expression vector containing a suitable eukaryotic promoter, a secretion signal, a poly A sequence, and a stop codon. Optionally, the vector or gene construct may contain enhancers and introns. In embodiments involving fusion proteins comprising an albumin binding protein or portion thereof, the expression vector optionally contains sequences encoding all or part of a constant region, enabling an entire, or a part of, a heavy or light chain to be expressed. The gene construct can be introduced into eukary otic host cells using conventional techniques.

[0221] In some embodiments, in order to express an albumin binding protein, an N-terminal signal sequence is included in the protein construct. Exemplary N-terminal signal sequences include signal sequences from interleukin-2, CD-5, IgG kappa light chain, trypsinogen, serum albumin, and prolactin.

[0222] After transfection, single clones can be isolated for cell bank generation using methods known in the art, such as limited dilution, ELISA, FACS, microscopy, or Clonepix. Clones can be cultured under conditions suitable for bio-reactor scale-up and maintained expression of the albumin binding proteins.

[0223] The albumin binding proteins and fusions thereof can be isolated and purified using methods known in the art including centrifugation, depth filtration, cell lysis, homogenization, freeze-thawing, affinity purification, gel filtration, ion exchange chromatography, hydrophobic interaction exchange chromatography, and mixed-mode chromatography.

[0224] Albumin binding proteins and fusions thereof may be humanized as described and provided herein, in accordance with methods known to those of skill in the art. Methods of characterization, such as those used herein, are also know n to those of skill in the art, including, but not limited to, for example, those used in Example 4, such as Affinity -capture selfinteraction nanoparticle spectroscopy (AC-SINs), Protein thermal stability test by Static Light Scattering (SLS) and Differential Scanning Fluorimetry (DSF), and Polyreactive ELISA analyses.

[0225] Those of ordinary skill in the art will be familiar with methods of amino acid diversification and / or substitution (e g., in CDRs, in FRs, etc.). Albumin binding proteins with diverse CDRs and / or FRs relative to those provided herein can be prepared and produced using methods provided herein and / or methods known to those of skill in the art to produce binding proteins that bind to an epitope of albumin.

[0226] In certain embodiments, the disclosure provides a method of generating a fusion protein comprising linking an albumin binding protein (DI) as provided herein (e.g, see TABLES 1-5E) to at least one additional component (D2).Methods of Use

[0227] Provided herein, in certain embodiments, are methods of using albumin binding proteins and fusions thereof.

[0228] In some aspects, the disclosure provides methods of using an albumin binding protein provided herein in a fusion protein. The method can comprise linking an albumin binding protein (DI) as provided herein (e.g, see TABLES 1-5E) to at least one additional component (D2). In certain embodiments, when D2 is linked to DI it shows one or more improvements on measures of half-life.

[0229] In some aspects, the disclosure provides methods of increasing half-life of a molecule (e.g, of a therapeutic molecule). In some embodiments, a method of increasing a half-life of a therapeutic molecule comprises administering a fusion protein an albumin binding protein (DI) as provided herein (see, e.g., TABLES 1-5E) linked to at least one additional component comprising or consisting of a therapeutic molecule (D2), wherein a half-life of the therapeutic molecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 alone (not in a fusion protein with DI ; not linked to DI).

[0230] In some aspects,, the disclosure provides a method of increasing a half-life of a therapeutic molecule in a subject in need thereof, the method comprising administering an effective amount of a fusion protein comprising an albumin binding protein (DI) as provided herein (see, e.g., TABLES 1-5E) linked to at least one additional component comprising or consisting of a therapeutic molecule (D2). wherein a half-life of the therapeutic molecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 alone (not in a fusion protein with DI; not linked to DI). In certain embodiments, the effective amount is lower when the subject is administered the fusion protein as compared to D2 alone. In certain embodiments, the frequency of administration is reduced when the subject is administered the fusion protein as compared to D2 alone (not in a fusion protein with DI; not linked to DI).

[0231] In some embodiments, half-life extension of the therapeutic molecule (D2) in the fusion protein is increased at least about 1.05-fold, 1.1-fold, 1.15-fold, 1.2-fold, 1.25-fold. 1.3-fold, 1.35-fold, 1.4-fold. 1.45-fold, 1.50-fold. 1.55-fold, 1.6-fold. 1.65-fold, 1.7-fold, 1.75-fold, 1.8- fold, 1.85-fold, 1.9-fold, 1.95-fold, 2-fold, 2.5-fold, 3-fold, 3.5-fold, 4-fold, 4.5-fold, 5-fold, 6- fold, 7-fold, 8-fold, 9-fold, 10-fold, 15-fold, 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 75-fold, 100-fold, 200-fold, 250-fold. 300-fold, 350-fold, 400-fold, 450-fold, 500-fold, 550-fold, 600- fold, 650-fold, 700-fold, 750-fold, 1,000-fold, 1,250-fold. 1,500-fold. 1,750-fold. 2,000-fold,2.250-fold, 2,500-fold, 2,750-fold, 3,000-fold, 3,250-fold, 3,500-fold, 3,750-fold, 4,000-fold,4.250-fold, 4,500-fold, 4,750-fold, 5,000-fold or greater as to D2 alone (not in the fusion protein; not linked to DI).

[0232] In some aspects, the disclosure provides a method of treating a subject in need thereof, the method comprising administering an effective amount of a fusion protein comprising an albumin binding protein (DI) according to the disclosure (see. e.g., TABLES 1-5E) linked to at least one additional component (D2) comprising or consisting of a therapeutic molecule, wherein a half-life of the therapeutic molecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 alone (not as a fusion comprising DI linked to D2).

[0233] In some aspects, the disclosure provides a method of increasing a half-life of a therapeutic molecule, the method comprising linking an albumin binding protein (DI) provided herein (see. e.g, TABLES 1-5E) to at least one additional component (D2) comprising or consisting of a therapeutic molecule, wherein the half-life of the therapeutic molecule after the linking is greater than before the linking.

[0234] In certain embodiments, administration of the fusion protein is subcutaneous. In certain embodiments, administration of the albumin binding protein is intravenous.

[0235] In one aspect, the disclosure provides a method of treating a disease or disorder in a patient in need thereof, the method comprising subcutaneously or intravenously administering to the patient an effective amount of a pharmaceutical composition comprising an albumin binding protein (DI) as provided herein (see, e.g., TABLES 1-5E) and at least one additional component (D2). In some embodiments, the additional component comprises a therapeutic molecule. In some embodiments, the patient is treated in a manner that is improved when compared to administration of the therapeutic molecule alone (not in the fusion) as compared to administration with the fusion.

[0236] Described herein, in certain embodiments, are methods of treating a disease or disorder in a patient in need thereof. In some embodiments, the disease or disorder is an albumin-mediated disease or disorder in a patient in need of treatment, the method comprising subcutaneously or intravenously administering to the patient an effective amount of an albumin binding protein comprising sequences selected from any of TABLES 1-5E, wherein the albumin binding protein may further have one or more components (D2) as described herein.

[0237] The albumin binding proteins may have one or more modifications (e.g., amino acid modifications) relative to a protein comprising the amino acid sequences of those disclosed in TABLES 1-3 and / or one or more modifications to one or more amino acids in any heavy chain region (e.g., CDR, FR), such as provided herein. In some embodiments, the albumin binding protein comprises or consists of a sequence set forth in any of TABLES 1-5E.

[0238] In some embodiments, one or more amino acids may be modified relative to those set forth in TABLES 1-5E.

[0239] Further provided herein, in certain embodiments, are methods of treating a disease or disorder in a patient in need thereof, the method comprising subcutaneously or intravenously administering to the patient an effective amount of a fusion protein comprising an albumin binding protein of the disclosure, wherein the albumin binding protein specifically binds to an epitope of albumin.

[0240] In some embodiments, administration of the albumin binding protein or fusion thereof is intravenous, intratumoral, intramuscular, subcutaneous, intralesional, intraintestinal, intracolonic, intrarectal, intrapouch, or intraperitoneal. In some embodiments, administration of the albumin binding protein or fusion thereof is through a parenteral route such as intravenous, intramuscular, subcutaneous, intraarterial, or intraperitoneal administration. In some embodiments, administration of the albumin binding protein or fusion thereof is intravenous or subcutaneous. In some embodiments, administration of the albumin binding protein or fusion thereof is intravenous. In some embodiments, administration of the albumin binding protein or fusion thereof is subcutaneous.

[0241] The disclosure now being generally described, will be more readily understood by reference to the following examples, which are included merely for purposes of illustration of certain aspects and embodiments of the present disclosure, and is not intended to limit the disclosure.EXAMPLESEXAMPLE 1: SYNTHESIS, EXPRESSION, & PURIFICATION OF ALBUMIN BINDING PROTEINS

[0242] This Example describes gene synthesis and expression, as well as purification of llama-derived albumin binding proteins. To begin, llamas were immunized with human albumin to generate VHH single domain antibodies against albumin. Phage display screening was conducted using the immune repertoire of immunized llamas cloned into an immune phage I i braiy which was selected used human and cynomolgus serum albumin proteins. The amino acid sequences of the resulting VHHs were determined using standard sequencing approaches. Gene synthesis and plasmid construction

[0243] The coding sequences for albumin binding proteins were generated by DNA synthesis and PCR, subsequently subcloned into pcDNA3.1 -based plasmid for protein expression in a mammalian cell system. The gene sequences in the expression vectors were confirmed by DNA sequencing.Expression of Antibodies

[0244] Transient expression of antibodies was performed using the ExpiCHO™ Expression System (ThermoFisher, Cat. No. A29133). The ExpiCHO-S cells were expanded from a working cell bank and passaged in ExpiCHO expression media according to the manufacturer’s instructions. The mixtures for transfection were prepared following the protocol instructions described in the ExpiCHO-S system manual. (Catalog Number A29133, Publication Number MAN0014337, Revision D.0). ExpiCHO cells were cultured for 14 days and the harvest was performed by filtration using 0.22 pm filtration units and DE as filter aid (Sartorius, Cat. No. SDLV-0150-05E0-2) after which they were processed immediately. The conditioned medium was harvested for protein purification.Purification of Antibodies

[0245] Produced antibodies were captured from clarified supernatants using a HiTrap MabSelect PrismA 25 mL column (Cytiva, Cat. Nr. 17-5498-54) on an AKTA Pure 25 FPLC system. The column equilibration and protein binding were performed using 20 mM sodium phosphate with 150 mM NaCl pH 7.4 and for protein elution, it was used 100 mM sodium citrate with 150 mM NaCl pH 3.5. After elution, the peak corresponding to affinity purified antibodies wasimmediately neutralized with 30 % of 1 M Tris pH 8.0. To polish the sample and to achieve a high purity > 95 % monomeric form, protein samples were loaded onto a HiToad 26 / 600 Superdex 200 pg (Cytiva, Cat. Nr. 28-9893-36) on an AKTA Pure 25 FPLC system. The fractions corresponding to the monomeric antibody form were pooled from a 96 deep well plate into a 50 ml falcon tube and filtered through a 0.22 pm PES membrane (Fisher brand, Cat. Nr. 15206869, Lot Nr. 2103171806) in a laminar flow chamber. Protein samples were transferred to 50 kDa MWCO spin concentrators (Amicon 50K Cat. Nr. UFC905024; Lot Nr. 0000187574) for concentration and each round of centrifugation was 10 min at 4000 x g, and it was repeated until the desired concentration was achieved.SEC-HPLC analysis

[0246] Analytical SEC-HPLC was performed on purified antibodies using Thermo Vanquish Flex UHPLC system (ThermoFisher) using a TSKgel Super SW mAb HTP (4.6 mm x 15.0 cm) column (Tosoh Bioscience, Cat. Nr. 00228559). Approximately 10 pg of sample was loaded. The mobile phase was 200 mM sodium phosphate, 0.05% sodium azide, pH 6.7 with a flow rate of 0.35 ml / min for 10 min 25°C. Resulting VHH sequences are shown in TABLE 1.EXAMPLE 2: GENERATION OF EXEMPLARY FUSION PROTEINS

[0247] This Example describes generation of exemplars’ fusion proteins as proof-of-concept and developability of exemplary VHH albumin binding proteins. Fusions of llama-derived VHH albumin binding proteins were made with (1) wild-type IgGl Fc (SEQ ID NO: 143); or (2) with a His tag (HHHHHHHH; SEQ ID NO: 161).

[0248] The N-terminus of the Fc of SEQ ID NO: 143 was linked to the C-terminus of the exemplary VHH albumin binding proteins via a G4S linker (SEQ ID NO: 144), according to an orientation, from N-to-C terminus of D1-L-D2, wherein DI was an exemplary VHH albumin binding protein, L was an exemplary' linker, and D2 was an exemplary second binding protein.

[0249] The His tag of SEQ ID NO: 161 was linked to the C-terminus of the exemplary VHH albumin binding proteins of SEQ ID NOs: 1-27 by a GG linker.Exemplary VHH-L-Fc fusion proteins are set forth in TABLE 7. Exemplary VHH-His tag fusion proteins are set forth in TABLE 8.TABLE 7. Exemplary VHH-Fc Fusion ProteinsTABLE 8. Exemplary VHH-His tag Fusion ProteinsEXAMPLE 3: ALBUMIN BINDING PROTEIN VHH FUSION BINDING KINETICS TO SERUM ALBUMIN USING SURFACE PLASMON RESONANCE (SPR)

[0250] This Example describes binding kinetics of VHH sequences provided by Example 1 and set forth in TABLE 1, which were made into exemplary fusion proteins as set forth in TABLE 7 of Example 2. Albumin binding VHH-Fc fusions of SEQ ID NOs: 54-74 were evaluated for binding kinetics to human, cynomolgus, mouse, and rat serum albumin at pH 6.0 (human, cynomolgus, rat, and mouse) and pH 7.4 (human and cynomolgus). A control VHH albumin binding domain of SEQ ID NO: 142(EVQLLESGGGLVQPGGSLRLSCAASGFT FRS FGMSWVRQAPGKGPEWVSS ISGSGSDTLYADSV KGRFTISRDNSKNTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVS S), comprising a CDR1 of SEQ ID NO: 29, a CDR2 of SEQ ID NO: 116, and a CDR3 of SEQ ID NO: 117 was fused to the wt Fc IgGl of SEQ ID NO: 143(DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVWDVSHEDPEVKFNWYVDGVEV HNAKTKPREEQYNSTYRWSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTT PPVLDSDGS FFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLS PG), with the linker of SEQ ID NO: 144. for a VHH-Fc fusion control (SEQ ID NO: 125).

[0251] A Biacore 8K SPR system (GE Healthcare) equipped with CM5 Sensor Chip (Cytiva, Cat. Nr. 29149603) immobilized with an anti -human Fc specific antibody by amine coupling, was used to determine the binding kinetic rate and affinity constants of Fc-fused anti-albumin VHHs at 25°C and in a running buffer of lxHBS-EP+ pH 6.0 or pH 7.4 (10 mM HEPES, 150 mM NaCl, 3 mM EDTA, 0.05% Surfactant P20) (Cytiva, Cat. BRI 00669). Following a stabilization period in running buffer, the anti-albumin mAb constructs at 20 nM were captured onto flow cell 2 (active) for 60 sec at a flow rate of 30 pL / min.

[0252] Recombinant human, cynomolgus, mouse, and rat serum albumin proteins were prepared at concentrations of 0, 31.25, 62.5, 125, 250, and 500 nM and injected over flow cell 1 (reference) and flow cell 2 (active) for 120 sec at a flow rate of 30 pL / min. Samples were injected in a multi-cycle manner over freshly captured mAb, by regenerating the capture surfaces with injection of 10 mM glycine pH 1.5 for 30 sec at a flow rate of 30 pL / min.The data were processed and analyzed with Biacore Insight Evaluation Software Version 2.0.15.12933 (GE Healthcare) as follows. Responses from flow cell 1 (reference) were subtracted from the responses from flow cell 2 (active). The responses from the two buffer blank injections were then subtracted from the reference subtracted data (2-1) to yield doublereferenced data, which were fit to a 1 : 1 binding model to determine the apparent association (ka) and dissociation rate constants (kd). Their ratio provided the apparent equilibrium dissociation constant or affinity constant (KD = kd / ka). Kinetics are shown in TABLES 9A (human and cynomolgus serum albumin at pH 6.0 and pH 7.4) and 9B (mouse and rat serum albumin at pH 6.0).TABLE 9A. Binding Kinetics Of Exemplary VHH-Fc Fusions (Human / Cynomolgus serum albumin)* - no value due to weak signalTABLE 9B. Binding Kinetics Of Exemplary VHH-Fc Fusions (mouse / rat serum albumin at pH 6.0)*N / D = not determined; no value due to very7weak signals.EXAMPLE 4: VHH FUSION CHARACTERIZATION AND IDENTIFICATION OF HUMANIZATION DEVELOPMENT CANDIDATES

[0253] This Example shows production and characterization of albumin binding VHH-Fc fusions of SEQ ID NOs: 54-74 and the albumin binding VHH-Fc fusion control (SEQ ID NO: 125). Protein yield (in mg / L) was measured, and characterization performed on AC-SINS, SLS and DSF, and Polyreactive ELISA assays as described herein.AC-SINS (Affinity-capture self-interaction nanoparticle spectroscopy)

[0254] Briefly, gold nanoparticles (15705; Ted Pella Inc.) were coated with 80% capturing antihuman goat IgG Fc (109-005-098; Jackson ImmunoResearch) and 20% with polyclonal goat nonspecific antibody (005-000-003; Jackson ImmunoResearch). The VHH fusions were then incubated with the particles for 2 h and the maximum wavelength shift was measured using Molecular Devices SpectraMax M2 with SoftMax Pro6 software. The wavelength shift (A max) of test samples away from the PBS sample were recorded for self-interacting assessment. Data are shown in TABLE 10.Protein thermal stability test by Static Light Scattering (SLS) and Differential Scanning Fluorimetry (DSF)

[0255] Albumin binding VHH fusion proteins in 20 mM sodium acetate pH 5.5 were loaded into a UNi (Unchained Labs). Samples were subjected to a thermal ramp from 20-95°C, with a ramp rate of 0.3°C / minute and ratio of the 330 / 350 nm fluorescence intensity and SLS at 266 nm against temperature were collected and UNCLE software was used to measure the peak of the 2nd derivatives of fluorescence ratio for the inflection points (Tm) of the transition curves, and SLS signal at 266 nm against temperature was used to determine Tagg. Data are shown in TABLE 10Polyreactive ELISA

[0256] In brief, dsDNA (1 pg / mL, D4522; Sigma) and insulin (5 pg / mL, 19278; Sigma) were coated onto ELISA plates (3369; Coming) individually at 50 pL per well overnight at 4 °C. Plates were blocked with PBS with 0.5% BSA at room temperature (RT) for 1 h, followed by three washes with PBST (PBS plus 0.1% Tween 20). Fifty microliters of 100 nM testing VHH fusion solution was added to each well and incubated at RT for 1 h followed by six washes with 100 pL of PBS. Fifty microliters of diluted anti-human IgG-HRP conjugate (81-7120; ZyMax) was added to the wells and incubated for 1 h followed by six washes. Finally, 50 pL of TMB substrate (34021; Fisher Scientific) was added to each well and incubated for 10-15 min. The reactions were stopped by adding 50 pL of 2 M sulfuric acid to each well. The absorbance was read at 450 nm and DNA or insulin score determined by normalizing absorbance by control wells with no test antibody. Data are shown in TABLE 10.

[0257] Based on the results of these characterization experiments, fusion protein VHH-4 (SEQ ID NO: 4; VHH-Fc Fusion SEQ ID NO: 57) was selected for humanization.TABLE 10. Yield And Developability CharacterizationEXAMPLE 5: HUMANIZATION AND FUSIONS

[0258] This Example describes humanization of exemplary VHH binding domain selected in Example 4: VHH-4 (SEQ ID NO: 4; VHH-Fc Fusion SEQ ID NO: 57).

[0259] Selected sequence was humanized by VH CDR grafting. AlphaFold2 was utilized to predict the VH model. Features taken into account for humanization include homology and developability. That is, homology (of human germline to parental sequence) is evaluated, and germline usage rate in existing humanized or human therapeutic monoclonal antibodies, and distribution of V region gene segments in the natural human antibody repertoire are considered. Here, IGHV3-23*04 was selected as the germline for VH CDR grafting for VHH-4 humanization. Humanized variant was formatted into two fusion orientations, each comprising an Fc component (D2) and an albumin binding protein component (DI), linked by a linker, L: (a) Orientation I: D1-L-D2 (albumin binding protein - linker - Fc) and (b) Orientation II: D2-L- D1 ( Fc- linker - albumin binding protein). The fusion proteins were tested via SPR kinetic screening to confirm their antigen binding strength. The linker in the Orientation I and Orientation II fusions was a G4S linker of SEQ ID NO: 144.

[0260] Resulting VHH sequences are set forth in TABLE 3, with CDRs set forth in TABLE 5. As in Example 3, Fc fusions and his-tag fusions were generated with the humanized VHH proteins.

[0261] The Fc fusions were as follows: the VHH domains were fused to a wild-type IgGl Fc of SEQ ID NO: 143 in one of two orientations: (a) Orientation I: C-terminus of the albumin binding VHH domain of any of SEQ ID NOs: 108-114 linked to the N-terminus of the Fc domain of SEQ ID NO: 143 through a linker of SEQ ID NO: 144 or (b) Orientation II: C-terminus of Fc domain of SEQ ID NO: 143 linked to the N-terminus of the albumin binding VHH domain of any of SEQ ID NOs: 108-114 through a linker of SEQ ID NO: 144. A control VHH albumin binding domain (SEQ ID NO: 142) that binds to human, cynomolgus, and mouse albumin was used to create control fusion proteins: (1) a control VHH-Fc fusion of SEQ ID NO: 125 and (2) a control Fc-VHH fusion of Orientation II (SEQ ID NO: 134, DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVWDVSHEDPEVKFNWYVDGVEV HNAKTKPREEQYNSTYRWSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQV YTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTT PPVLDSDGS FFLYSKLTV DKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGGGGGSEVQLLESGGGLVQPGGSLRLSCAAS GFTFRS FGMSWVRQAPGKGPEWVSS ISGSGSDTLYADSVKGRFTISRDNSKNTLYLQMNSLRPE DTAVYYCTIGGSLSRSSQGTLVTVSS) that were also used in subsequent characterization experiments.

[0262] His tag fusions were made by fusing a his-tag (HHHHHHHH, SEQ ID NO: 161) to the albumin binding VHH domains of each of SEQ ID NOs: 108-114).

[0263] Llama (non-humanized) sequences of VHH-4 (SEQ ID NO: 4) was also used to generate Fc fusions of Orientation II (see TABLE 12, SEQ ID NO: 126). The fusion proteins are set forthin TABLE 11 (VHH-Fc fusions), TABLE 12 (Fc-VHH fusions), and TABLE 13 (VHH-His tag fusions).TABLE 11. Exemplary Humanized VHH-Fc Fusion ProteinsTABLE 12. Exemplary Humanized VHH-Fc Fusion ProteinsTABLE 13. Exemplary Humanized VHH-His tag Fusion ProteinsEXAMPLE 6: HUMANIZED ALBUMIN BINDING PROTEIN VHH FUSION BINDING KINETICS TO SERUM ALBUMIN USING SURFACE PLASMON RESONANCE (SPR)

[0264] This Example describes binding kinetics of VHH sequences provided by Example 5 and set forth in TABLES 4-5, which were made into exemplary fusion proteins as set forth in TABLE 11 and TABLE 12 of Example 5, were evaluated for binding kinetics. Albumin binding VHH-Fc of SEQ ID NO: 57, and 118-124 and Fc-VHH fusions of SEQ ID NOs: 126- 133 were evaluated for binding kinetics to human serum albumin at pH 6.0 and pH 7.4. The control VHH-Fc of SEQ ID NO: 125 and control Fc-VHH of SEQ ID NO: 134 were also measured.

[0265] Similar to Example 3, a Biacore 8K SPR system (GE Healthcare) equipped with CM5 Sensor Chip (Cytiva. Cat. Nr. 29149603)) immobilized with an anti-human Fc specific antibodyby amine coupling, was used to determine the binding kinetic rate and affinity constants of Fc- fused anti-albumin VHHs at 25°C and in a running buffer of lxHBS-EP+ pH 6.0 or pH 7.4 (10 mM HEPES, 150 mM NaCl, 3 mM EDTA, 0.05% Surfactant P20) (Cytiva, Cat. BR100669). Following a stabilization period in running buffer, the anti-albumin mAb constructs at 20 nM were captured onto flow cell 2 (active) for 60 sec at a flow rate of 30 pL / min.

[0266] Recombinant human serum albumin proteins were prepared at concentrations of 0, 31.25, 62.5, 125, 250, and 500 nM and injected over flow cell 1 (reference) and flow cell 2 (active) for 120 sec at a flow rate of 30 pL / min. Samples were injected in a multi-cycle manner over freshly captured mAb. by regenerating the capture surfaces with injection of 10 mM glycine pH 1.5 for 30 sec at a flow rate of 30 pL / min.

[0267] The data were processed and analyzed with Biacore Insight Evaluation Software Version 2.0.15.12933 (GE Healthcare) as follows. Responses from flow cell 1 (reference) were subtracted from the responses from flow cell 2 (active). The responses from the two buffer blank injections were then subtracted from the reference subtracted data (2-1) to yield doublereferenced data, which were fit to a 1 : 1 binding model to determine the apparent association (ka) and dissociation rate constants (kd). Their ratio provided the apparent equilibrium dissociation constant or affinity constant (KD = kd / ka). Kinetics are shown in TABLES 14A (VHH-Fc pH 6.0 and pH 7.4) and 14B (Fc-VHH at pH 6.0 and pH 7.4).TABLE 14A. Binding Kinetics Of Exemplary Humanized VHH-Fc Fusions (Human serum albumin)*N / A - no binding; N / D = not determined.TABLE 14B. Binding Kinetics Of Exemplary Humanized Fc-VHH Fusions (Human serum albumin)*N / A - no binding; N / D = not determined.INCORPORATION BY REFERENCE

[0268] All publications and patents cited throughout the text of this specification (including all patents, patent applications, scientific publications, manufacturer's specifications, instructions, etc. ), whether supra or infra, are hereby incorporated by reference in their entirety for all purposes. To the extent the material incorporated by reference contradicts or is inconsistent with this specification, the specification will supersede any such material.EQUIVALENTS

[0269] The disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting the disclosure described herein. Scope of the disclosure is thus indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

CLAIMSWhat is claimed is:

1. An albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3, wherein:(a) the CDR1 has an amino acid sequence comprising or consisting of SEQ ID NO: 29;(b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NO: 31; and(c) the CDR3 has an amino acid sequence comprising or consisting of SEQ ID NO: 45.

2. An albumin binding protein comprising: a VHH domain, the VHH domain comprising three complementarity determining regions (CDRs), CDR1, CDR2, and CDR3, wherein:(a) the CDR1 has an amino acid sequence selected from the group consisting of SX32GMS, wherein X32 is F or A, and SFGX34S, wherein X34 is M or A;(b) the CDR2 has an amino acid sequence comprising or consisting of SEQ ID NO: 31; and(c) the CDR3 has an amino acid sequence comprising or consisting of SEQ ID NO: 45.

3. The albumin binding protein of claim 2, wherein the CDR1 has an amino acid sequence comprising SFGMS (SEQ ID NO: 29).

4. The albumin binding protein of claim 2, wherein the CDR1 has an amino acid sequence comprising SAGMS (SEQ ID NO: 178).

5. The albumin binding protein of claim 2, wherein the CDR1 has an amino acid sequence comprising SFGAS (SEQ ID NO: 179).

6. The albumin binding protein of any one of claims 1-5, further comprising at least one additional component (D2), linked to the albumin binding protein (DI) according to a formula, from N-to-C terminus, of: (a) D1-L-D2, or (b) D2-L-D1, wherein DI comprises the albumin binding protein according to claim 1; D2 comprises the at least one additional component; and L comprises a linker.

7. The albumin binding protein of claim 6, wherein D2 comprises a second antigen binding protein or a non-antigen binding moiety.

8. The albumin binding protein of claim 6 or 7, wherein the linker is or comprises a peptide linker.

9. The albumin binding protein of any of claims 6-8, wherein the linker has an amino acid sequence comprising any one of SEQ ID NOs: 144-159.

10. The albumin binding protein of any one of claims 6-9, wherein the linker has an amino acid sequence comprising, consisting essentially of, or consisting of SEQ ID NO: 144.

11. The albumin binding protein of any one of claims 6-10, further comprising one, two, three, four or more additional antigen-binding proteins or non-antigen binding moieties, wherein each additional antigen binding protein or non-antigen binding moiety is optionally linked to DI or another additional antigen binding protein or non-antigen binding moiety by a linker.

12. The albumin binding protein of any one of claims 6-11, wherein D2 comprises an antigen binding protein selected from a single chain antibody or binding fragment thereof (e.g, scFv (e.g, a bispecific scFv), e.g., a single heavy chain, a single light chain, a variable heavy-chain domain (e.g., a VHH), a variable light-chain domain, a variable NAR domain, a single chain polypeptide), an F(ab’), an F(ab')2 (e.g, a bi-specific F(ab’)2), an F(Ab’)3 (e.g, a tri-specific F(Ab’)3), an Fv, a DARPin, an Fc domain (e.g, an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.), a minibody, a diabody, a dAb fragment, an antibody (e.g, a monoclonal antibody), a multispecific binding protein (e.g, bispecific antibody), and combinations thereof.

13. The albumin binding protein of any one of claims 6-12, wherein the antigen binding protein of D2 comprises a variable heavy chain domain comprising or consisting of a VHH domain.

14. The albumin binding protein of any one of claims 6-13, wherein D2 comprises a nonantigen binding moiety selected from a detectable tag (e.g, a His tag. a Flag tag, a fluorescent tag), and an Fc domain (e.g., an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.).

15. The albumin binding protein of any one of claims 1-14. wherein a binding affinity of the albumin binding protein for albumin is stronger than about 10 pM, about 7.5 pM, about 5 pM, about 2.5 pM, about 1 pM, about 0.75 pM, about 0.5 pM, about 0.25 pM, about 0.1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM. about 3 nM, about 2 nM, about 1 nM, about 0.75 nM. about 0.5 nM, about 0.25 nM, about 0.1 nM, about 0.01 nM, or about 0.001 nM.

16. The albumin binding protein of claim 15, wherein the binding affinity of the albumin binding protein for albumin is stronger than about 0. 1 pM, about 75 nM, about 50 nM, about 25nM, about 10 nM, about 9 nM. about 8 nM, about 7 nM, about 6 nM. about 5 nM, about 4 nM. about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0.1 nM, or about 0.01 nM.

17. The albumin binding protein of any one of claims 1-16. wherein the albumin binding protein binds to albumin with a KD of less than or equal to about 1 x 10'6M at pH 6.0 or pH 7.4 as measured by surface plasmon resonance (SPR).

18. The albumin binding protein of any one of claims 1-16. wherein the albumin binding protein binds to albumin with a KD of less than or equal to about I x 1 O'7M at pH 6.0 or pH 7.4 as measured by SPR.

19. The albumin binding protein of any one of claims 1-16. wherein the albumin binding protein binds to albumin with a KD of less than or equal to about 1 x 10'8M at pH 6.0 or pH 7.4 as measured by SPR.

20. The albumin binding protein of any one of claims 1-16. wherein the albumin binding protein binds to albumin with a KD of less than or equal to about 1 x 10'9M at pH 6.0 or pH 7.4 as measured by SPR.

21. The albumin binding protein of any one of claims 1-20. wherein the albumin binding protein has been humanized.

22. The albumin binding protein of any one of claims 1-21, wherein the binding affinity of the albumin binding protein for albumin is stronger at pH 6.0 than at pH 7.4.

23. The albumin binding protein of any one of claims 1-21, wherein the binding affinity of the albumin binding protein for albumin is stronger at pH 7.4 than at pH 6.0.

24. The albumin binding protein of any one of claims 1-21, wherein the binding affinity of the albumin binding protein for albumin is substantially unchanged betw een pH 6.0 and pH 7.4.

25. An albumin binding protein comprising a VHH domain comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 108-114 and 173-175.

26. An albumin binding protein consisting of an amino acid sequence selected from the group consisting of SEQ ID NOs: 108-114 and 173-175.

27. A pharmaceutical composition comprising(a) a fusion protein comprising two domains, DI, and D2, wherein:(i) DI comprises the albumin binding protein of any of claims 1. 2, 25. or 26; and(ii) D2 comprises at least one additional component comprising an antigen binding protein or a non-antigen binding moiety; and(b) a pharmaceutically acceptable excipient.

28. The pharmaceutical composition of claim 27, wherein the DI and the D2 domains of the fusion protein are linked by a linker according to a formula, from N-to-C terminus, of (a) Dl-L- D2 or (b) D2-L-D1, wherein L is the linker.

29. The pharmaceutical composition of claim 28, wherein the linker is or comprises a peptide linker.

30. The pharmaceutical composition of claim 28 or 29, wherein the linker has an amino acid sequence comprising any one of SEQ ID NOs: 144-159.

31. The pharmaceutical composition of claim 29 or 30, wherein the linker has an amino acid sequence comprising, consisting essentially of, or consisting of the amino acid sequence of SEQ ID NO: 144.

32. The pharmaceutical composition of any one of claims 27-31, further comprising one, two, three, four or more additional antigen binding proteins or non-antigen binding moieties.

33. The pharmaceutical composition of any one of claims 27-32, wherein D2 comprises a second antigen binding fragment selected from a single chain antibody or binding fragment thereof (e.g., scFv (e.g, a bispecific scFv), e.g, a single heavy chain, a single light chain, a variable heavy-chain domain (e.g., a VHH), a variable light-chain domain, a variable NAR domain, a single chain polypeptide), an F(ab’), an F(ab’)2 (e.g., a bi-specific F(ab’)2), an F(Ab’)3 (e.g., a tri-specific F(Ab’)3), an Fv, a DARPin, an Fc domain (e.g., an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.), a minibody, a diabody. a dAb fragment, an antibody (e.g.. a monoclonal antibody), a multispecific binding protein (e.g., bispecific antibody), and combinations thereof.

34. The pharmaceutical composition of any one of claims 27-33, wherein D2 comprises a variable heavy chain domain comprising or consisting of a VHH domain.

35. The pharmaceutical composition of any one of claims 27-33, wherein D2 comprises a nonantigen binding moiety selected from a detectable tag (e.g., a His tag, a Flag tag, a fluorescenttag) and an Fc domain (e.g, an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-type, an Fc fragment, etc.).

36. The pharmaceutical composition of any one of claims 27-35, wherein a binding affinity of the albumin binding protein of DI for albumin is stronger than about 10 pM. about 7.5 pM, about 5 pM, about 2.5 pM, about 1 pM, about 0.75 pM, about 0.5 pM, about 0.25 pM, about 0.1 pM, about 75 nM, about 50 nM, about 25 nM, about 10 nM, about 9 nM, about 8 nM, about 7 nM, about 6 nM, about 5 nM, about 4 nM, about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0.1 nM. about 0.01 nM, or about 0.001 nM.

37. The pharmaceutical composition of claim 36, wherein the binding affinity of the albumin binding protein of DI for albumin is stronger than about 0. 1 pM, about 75 nM, about 50 nM, about 25 nM. about 10 nM, about 9 nM, about 8 nM, about 7 nM. about 6 nM, about 5 nM, about 4 nM, about 3 nM, about 2 nM, about 1 nM, about 0.75 nM, about 0.5 nM, about 0.25 nM, about 0.1 nM, or about 0.01 nM.

38. The pharmaceutical composition of any one of claims 27-37, wherein the albumin binding protein of DI binds to albumin with a KD of less than or equal to about 1 x 10’7M at pH 6.0 or pH 7.4 as measured by SPR.

39. The pharmaceutical composition of any one of claims 27-37, wherein the albumin binding protein of DI binds to albumin with a KD of less than or equal to about 1 x 10’8M at pH 6.0 or pH 7.4 as measured by SPR.

40. The pharmaceutical composition of any one of claims 27-37, wherein the albumin binding protein of DI binds to albumin with a KD of less than or equal to about 1 x 10’9M at pH 6.0 or pH 7.4 as measured by SPR.

41. The pharmaceutical composition of any one of claims 27-40, wherein the albumin binding protein of DI has been humanized.

42. The pharmaceutical composition of any one of claims 27-40, wherein the binding affinity of the albumin binding protein of DI for albumin is stronger at pH 6.0 than at pH 7.4.

43. The pharmaceutical composition of any one of claims 27-40, wherein the binding affinity of the albumin binding protein of DI for albumin is stronger at pH 7.4 than at pH 6.0.

44. The pharmaceutical composition of any one of claims 27-40, wherein the binding affinity of the albumin binding protein of DI for albumin is substantially unchanged between pH 6.0 and pH 7.4.

45. A fusion protein comprising at least two domains according to a formula, from N-to-C terminus, of:(a) Orientation I: D1-L-D2; or(b) Orientation II: D2-L-D1, wherein DI is the albumin binding protein according to any one of claims 1, 2, 25, or 26; L is a linker; and D2 is an additional protein binding domain or non-antigen binding domain.

46. The fusion protein of claim 45, wherein the albumin binding protein binds with a stronger affinity when arranged in a configuration comprising D1-L-D2 as compared to D2-L-D1 when measured by SPR.

47. The fusion protein of claim 45, wherein the albumin binding protein binds with a stronger affinity when arranged in a configuration comprising D2-L-D1 as compared to D1-L-D2 when measured by SPR.

48. The fusion protein of claim 45 or 46, wherein the albumin binding affinity of the albumin binding protein in orientation I is stronger than that of the albumin binding protein in orientation II at pH 6.0 and / or pH 7.4.

49. The fusion protein of claim 45, wherein the albumin binding affinity of the albumin binding protein in orientation I is substantially unchanged as compared to that of the albumin binding protein in orientation II at pH 6.0 and / or pH 7.4.

50. The fusion protein of claim 45 or 47, wherein the albumin binding affinity of the albumin binding protein in orientation II is stronger than that of the albumin binding protein in orientation I at pH 6.0 and / or pH 7.4.

51. A method of generating a fusion protein comprising linking an albumin binding protein (DI) of any one of claims 1, 2, 25, or 26, to at least one additional component (D2), wherein when D2 is linked to DI it shows one or more improvements on measures of half-life.

52. A method of increasing a half-life of a therapeutic molecule, the method comprising administering a fusion protein comprising: the albumin binding protein, (DI), of any one ofclaims 1.

2.

25. or 26, linked to at least one additional component comprising or consisting of a therapeutic molecule, (D2), wherein a half-life of the therapeutic molecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 not linked to DI.

53. A method of increasing a half-life of a therapeutic molecule in a subject in need thereof, the method comprising administering an effective amount of a fusion protein comprising the albumin binding protein (DI) of any one of claims 1, 2, 25, or 26, linked to at least one additional component comprising or consisting of a therapeutic molecule (D2), wherein a half-life of the therapeutic molecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 not linked to D 1.

54. The method of claim 52 or 53. wherein the half-life of the therapeutic molecule in the fusion protein is increased by at least about 1.05-fold, 1.1-fold, 1.15-fold, 1.2-fold, 1.25-fold, 1.3- fold, 1.35-fold, 1.4-fold, 1.45-fold, 1.50-fold, 1.55-fold, 1.6-fold, 1.65-fold, 1.7-fold, 1.75-fold, 1.8-fold, 1.85-fold, 1.9-fold, 1.95-fold, 2-fold, 2.5-fold, 3-fold, 3.5-fold, 4-fold, 4.5-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold. 10-fold, 15-fold, 20-fold, 25-fold, 30-fold, 40-fold, 50-fold, 75-fold, 100-fold. 200-fold. 250-fold. 300-fold, 350-fold, 400-fold, 450-fold, 500-fold, 550-fold, 600-fold, 650-fold, 700-fold, 750-fold, 1,000-fold, 1,250-fold, 1,500-fold, 1,750-fold, 2,000-fold, 2,250- fold, 2,500-fold, 2,750-fold, 3,000-fold, 3,250-fold, 3,500-fold, 3,750-fold, 4,000-fold, 4,250- fold, 4,500-fold, 4,750-fold, 5,000-fold or greater as compared to the therapeutic molecule not in the fusion protein.

55. The method of claim 53 or 54, wherein the effective amount is lower when the subject is administered the fusion protein as compared to D2 not linked to DI.

56. The method of any one of claims 53-55, wherein the frequency of administration is reduced when the subject is administered the fusion protein as compared to D2 not linked to DI.

57. A method of treating a subject in need thereof, the method comprising administering an effective amount of a fusion protein comprising the albumin binding protein (DI) of any one of claims 1, 2, 25, or 26, linked to at least one additional component (D2) comprising or consisting of a therapeutic molecule, wherein a half-life of the therapeutic molecule is greater when administered as the fusion protein comprising DI and D2 than when administered as D2 not linked to D 1.

58. A method of increasing a half-life of a therapeutic molecule, the method comprising linking the albumin binding protein, DI, of any one of claims 1, 2, 25, or 26, to at least one additional component, D2, comprising or consisting of a therapeutic molecule, wherein the half-life of the therapeutic molecule after the linking is greater than before the linking.

59. The method of any one of claims 53-58, wherein administration of the fusion protein is subcutaneous.

60. The method of any one of claims 53-58. wherein administration of the albumin binding protein is intravenous.

61. A method of treating a disease or disorder in a patient in need thereof, the method comprising subcutaneously or intravenously administering to the patient an effective amount of a pharmaceutical composition of any one of claims 27-44.

62. The method of any one of claims 48-58, wherein DI and D2 are linked by a linker that is or comprises a peptide linker.

63. The method of any one of claims 51-61, wherein DI and D2 are linked by a linker having an amino acid sequence comprising any one of SEQ ID NOs: 144-159.

64. The method of claim 62 or 63, wherein the linker has an amino acid sequence comprising, consisting essentially of, or consisting of SEQ ID NO: 144.

65. A polynucleotide encoding the albumin binding protein of any one of claims 1. 2, 25, or 26.

66. A polynucleotide encoding a fusion protein comprising, from N-to-C terminus, D1-L-D2, wherein DI comprises or consists of the albumin binding protein of any one of claims 1, 2. 25, or 26; L is a linker; and D2 is at least one additional component comprising or consisting of a therapeutic molecule or a detectable molecule.

67. A polynucleotide encoding a fusion protein comprising, from N-to-C terminus, D2-L-D1, wherein DI comprises or consists of the albumin binding protein of any one of claims 1, 2.

25. or 26; L is a linker; and D2 is at least one additional component comprising or consisting of a therapeutic molecule or a detectable molecule.

68. The polynucleotide of claim 66 or 67, wherein the linker is or comprises a peptide linker.

69. The polynucleotide of any one of claims 66-68, wherein the linker has an amino acid sequence comprising any one of SEQ ID NOs: 144-159.

70. The polynucleotide of any one of claims 66-69. wherein the linker has an amino acid sequence comprising, consisting essentially of, or consisting of SEQ ID NO: 144.

71. The polynucleotide of any one of claims 66-70, wherein the therapeutic molecule is selected from a single chain antibody or binding fragment thereof (e.g.. scFv (e.g, a bispecific scFv), e.g., a single heavy chain, a single light chain, a variable heavy-chain domain (e.g., a VHH), a variable light-chain domain, a variable NAR domain, a single chain polypeptide), an F(ab'), an F(ab’)2 (e.g., a bi-specific F(ab')2), an F(Ab')3 (e.g., a tri-specific F(Ab’)3), an Fv, a DARPin. an Fc domain (e.g., an entire Fc. a modified Fc domain, an Fc domain with one or more substitutions relative to wild-ty pe, an Fc fragment, etc.), a minibody, a diabody, a dAb fragment, a multispecific binding protein (e.g., bispecific antibody), and combinations thereof.

72. The polynucleotide of any one of claims 66-71, wherein the at least one additional component comprises or consists of detectable molecule selected from a his tag, a flag tag, a fluorescent tag, and / or an Fc domain (e.g., an entire Fc, a modified Fc domain, an Fc domain with one or more substitutions relative to wild-ty pe, an Fc fragment, etc.).

73. A host cell comprising the polynucleotide of any one of claims 65-72.

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