Actriia binding agents and uses thereof

Abstract

The disclosure provides, among other aspects, neutralizing antibodies and portions thereof that bind to ActRIIA and uses for same.

1 . An isolated antibody or fragment thereof that inhibits binding of activin A to human ActRIIA. 
     
     
         2 . The isolated antibody or fragment thereof of  claim 1 , that binds to human ActRIIa and cross-blocks the binding of Ab-14E1 to human ActRIIA. 
     
     
         3 . The isolated antibody or fragment thereof that inhibits binding of activin A and activin B to human ActRIIA. 
     
     
         4 . The antibody or fragment thereof of  claim 1  wherein said anti-ActRIIA antibody or fragment has an activity selected from the group consisting of: (a) reduces follicle-stimulating hormone levels in vivo, and (b) inhibits activin A signaling in a cell line in vitro. 
     
     
         5 . The antibody or fragment thereof of  claim 1  wherein said anti-ActRIIA antibody or fragment has an activity selected from the group consisting of: (a) reduces follicle-stimulating hormone levels in an ovariectomized, female C57BL/6 mouse, and (b) inhibits expression of a CAGA12-regulated reporter gene in an A204 cell line exposed to activin A. 
     
     
         6 . The isolated antibody or fragment thereof of  claim 1 , wherein said antibody or fragment thereof contacts one or more amino acids in the extracellular domain of human ActRIIA, selected from a group consisting of:
 a. a phenylalanine at position 13 of SEQ ID NO: 16,   b. a phenylalanine at position 14 of SEQ ID NO: 16,   c. an asparagine at position 15 of SEQ ID NO: 16,   d. an asparagine at position 17 of SEQ ID NO: 16,   e. an aspartate at position 21 of SEQ ID NO: 16,   f. an arginine at position 22 of SEQ ID NO: 16,   g. a threonine at position 23 of SEQ ID NO: 16,   h. a glutamate at position 29 of SEQ ID NO: 16,   i. a proline at position 30 of SEQ ID NO: 16,   j. a cysteine at position 31 of SEQ ID NO: 16,   k. a tyrosine at position 32 of SEQ ID NO: 16,   l. a glycine at position 33 of SEQ ID NO: 16,   m. an aspartate at position 34 of SEQ ID NO: 16,   n. an aspartate at position 36 of SEQ ID NO: 16,   o. a lysine at position 37 of SEQ ID NO: 16,   p. an arginine at position 39 of SEQ ID NO: 16,   q. a histidine at position 40 of SEQ ID NO: 16,   r. a phenylalanine at position 42 of SEQ ID NO: 16,   s. a threonine at position 44 of SEQ ID NO: 16,   t. a lysine at position 46 of SEQ ID NO: 16,   u. a valine at position 55 of SEQ ID NO: 16,   v. a lysine at position 56 of SEQ ID NO: 16,   w. a glutamine at position 57 of SEQ ID NO: 16,   x. a glycine at position 58 of SEQ ID NO: 16,   y. a cysteine at position 59 of SEQ ID NO: 16,   z. a tryptophan at position 60 of SEQ ID NO: 16,   aa. a leucine at position 61 of SEQ ID NO: 16,   bb. an aspartate at position 62 of SEQ ID NO: 16,   cc. an aspartate at position 63 of SEQ ID NO: 16,   dd. an isoleucine at position 64 of SEQ ID NO: 16,   ee. an asparagine at position 65 of SEQ ID NO: 16,   ff. a cysteine at position 66 of SEQ ID NO: 16,   gg. a lysine at position 76 of SEQ ID NO: 16,   hh. a glutamate at position 80 of SEQ ID NO: 16,   ii. a valine at position 81 of SEQ ID NO: 16,   jj. a phenylalanine at position 83 of SEQ ID NO: 16, and   kk. a cysteine at position 85 of SEQ ID NO: 16.   
     
     
         7 . The isolated antibody or fragment thereof of  claim 1 , wherein said antibody or fragment thereof comprises one or more amino acids selected from a group of VH residues consisting of:
 a. a valine at position −20 from cysteine 1  of SEQ ID NO: 12,   b. a glycine at position +4 from cysteine 1  of SEQ ID NO: 12,   c. a tyrosine at position +5 from cysteine 1  of SEQ ID NO: 12,   d. a serine at position +9 from cysteine 1  of SEQ ID NO: 12,   e. a glycine at position +10 from cysteine 1  of SEQ ID NO: 12,   f. a tyrosine at position +11 from cysteine 1  of SEQ ID NO: 12,   g. a tyrosine at position +12 from cysteine 1  of SEQ ID NO: 12,   h. a tyrosine at position +32 from cysteine 1  of SEQ ID NO: 12,   i. an asparagine at position +37 from cysteine 1  of SEQ ID NO: 12,   j. an alanine at position +4 from cysteine 2  of SEQ ID NO: 12,   k. a tyrosine at position +5 from cysteine 2  of SEQ ID NO: 12,   l. an arginine at position +6 from cysteine 2  of SEQ ID NO: 12,   m. an asparagine at position +7 from cysteine 2  of SEQ ID NO: 12,   n. an aspartate at position +8 from cysteine 2  of SEQ ID NO: 12,   o. an arginine at position +10 from cysteine 2  of SEQ ID NO: 12,   p. an alanine at position +12 from cysteine 2  of SEQ ID NO: 12,   q. a tyrosine at position +13 from cysteine 2  of SEQ ID NO: 12; and   r. a conservative substitution of any of the foregoing.   
     
     
         8 . The isolated antibody or fragment thereof of  claim 1 , wherein said antibody or fragment thereof comprises one or more amino acids selected from a group of VL residues consisting of:
 a. an aspartate at position +5 from cysteine 1  of SEQ ID NO: 13,   b. a serine at position +7 from cysteine 1  of SEQ ID NO: 13,   c. an asparagine at position +8 from cysteine 1  of SEQ ID NO: 13,   d. a phenylalanine at position +9 from cysteine 1  of SEQ ID NO: 13,   e. a tyrosine at position +26 from cysteine 1  of SEQ ID NO: 13,   f. a phenylalanine at position +27 from cysteine 1  of SEQ ID NO: 13,   g. a serine at position +29 from cysteine 1  of SEQ ID NO: 13,   h. an arginine at position +30 from cysteine 1  of SEQ ID NO: 13,   i. a leucine at position +31 from cysteine 1  of SEQ ID NO: 13,   j. a serine at position +33 from cysteine 1  of SEQ ID NO: 13,   k. a serine at position −21 from cysteine 2  of SEQ ID NO: 13,   l. a glycine at position +3 from cysteine 2  of SEQ ID NO: 13,   m. an asparagine at position +4 from cysteine 2  of SEQ ID NO: 13,   n. a threonine at position +5 from cysteine 2  of SEQ ID NO: 13,   o. a leucine at position +6 from cysteine 2  of SEQ ID NO: 13,   p. a tryptophan at position +8 from cysteine 2  of SEQ ID NO: 13, and   q. a conservative substitution of any of the foregoing.   
     
     
         9 . The antibody or fragment thereof of  claim 1  that comprises at least one CDR sequence having at least 80% identity to a CDR selected from the group consisting of SEQ ID NOs: 4, 5, 6, 7, 8, and 9. 
     
     
         10 . The antibody or fragment thereof of  claim 1  that comprises at least two, at least three, at least four, at least five or at least six CDR sequences having at least 80% identity to a CDR selected from the group consisting of SEQ ID NOs: 4, 5, 6, 7, 8, and 9. 
     
     
         11 . The antibody or fragment thereof according to  claim 1  comprising three CDRs, CDR-H1, CDR-H2, and CDR-H3, wherein CDR-H1 comprises a sequence that is at least 80% identical to SEQ ID NO: 4, CDR-H2 comprises a sequence that is at least 80% identical to SEQ ID NO: 5, and CDR-H3 comprises a sequence that is at least 80% identical to SEQ ID NO: 6. 
     
     
         12 . The antibody or fragment thereof according to  claim 1  comprising a heavy chain wherein said heavy chain comprises a polypeptide having at least 80% identity to the sequence given in SEQ ID NO: 12. 
     
     
         13 . The antibody or fragment thereof according to  claim 1  comprising a light chain wherein said light chain comprises a polypeptide having at least 80% identity to the sequence given in SEQ ID NO: 13. 
     
     
         14 . The antibody or fragment thereof according to  claim 1  comprising both a heavy chain and a light chain wherein the heavy chain comprises a polypeptide having at least 80% identity to the sequence given in SEQ ID NO: 12 and the light chain comprises a polypeptide having at least 80% identity to the sequence given in SEQ ID NO: 13. 
     
     
         15 . A method of generating an ActRIIA binding agent, the method comprising immunizing a viable, homozygous ActRIIA-deficient mouse with antigen polypeptide derived from ActRIIA. 
     
     
         16 . A method of treating a condition in a patient having undesired ActRIIA-dependent signaling comprising administering to a patient in need thereof an effective amount of an antibody of  claim 1 . 
     
     
         17 . The method according to  claim 16  in which the condition is characterized by insufficient lean body mass. 
     
     
         18 . The method according to  claim 16  in which the condition is characterized by a decrease in muscle mass or muscle function. 
     
     
         19 . The method according to  claim 16  in which the condition is cancer cachexia or sarcopenia. 
     
     
         20 . The method according to  claim 16  in which the patient has undesirably high levels of follicle-stimulating hormone. 
     
     
         21 . A pharmaceutical composition comprising the antibody or fragment of  claim 1 . 
     
     
         22 . The antibody or fragment thereof according to  claim 1  in combination with one or more of a pharmaceutically acceptable excipient, diluent, or carrier. 
     
     
         23 . The antibody or fragment thereof according to  claim 1  conjugated to at least one of Fc, polyethylene glycol, albumin, and transferrin.