Methods for treating muscle wasting and bone disease using novel hybrid actriib ligand trap proteins

Abstract

The present disclosure describes novel hybrid soluble ActRIIB-ECD polypeptides which fully retain binding affinity for myostatin and activin A but demonstrate significantly reduced binding to BMPs, especially BMP-9. The novel compositions described herein can be used to prepare novel hybrid ActRIIB ligand trap proteins, which can be used for modulating the growth of muscle, bone, cartilage, fat, fibroblast, blood and neuronal tissue to counteract muscle wasting, bone loss, anemia, inflammation and fibrosis in a therapeutically meaningful manner. Because these novel next-generation myostatin/activin inhibitors are safer and more effective molecules than the currently available myostatin inhibitors, they are useful in a wide variety of clinical indications.

1 - 39 . (canceled) 
     
     
         40 . An isolated hybrid activin IIB receptor (ActRIIB) ligand trap protein comprising a hybrid soluble ActRIIB-extracellular domain (ActRIIB-ECD) polypeptide, wherein said hybrid soluble ActRIIB-ECD polypeptide comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 3-37 and 51-117. 
     
     
         41 . The isolated hybrid ActRIIB ligand trap protein of  claim 40 , wherein said hybrid ActRIIB ligand trap protein further comprises an Fc domain of a human immunoglobulin, wherein said Fc domain comprises an amino acid sequence selected from the group consisting of: SEQ ID NO: 39, SEQ ID NO: 41, and SEQ ID NO: 43. 
     
     
         42 . The isolated hybrid ActRIIB ligand trap protein of  claim 41 , wherein a peptide linker comprising the amino acid sequence set forth in SEQ ID NO: 44 is used with a hinge linker comprising the amino acid sequence set forth in SEQ ID NO: 118 to link the Fc domain to the hybrid soluble ActRIIB-ECD polypeptide. 
     
     
         43 . The isolated hybrid ActRIIB ligand trap protein of  claim 42 , wherein said hybrid soluble ActRIIB-ECD polypeptide comprises the amino acid sequence of SEQ ID NO: 16, wherein said hybrid soluble ActRIIB-ECD polypeptide is fused to a peptide linker comprising the amino acid sequence set forth in SEQ ID NO: 44, wherein said peptide linker is fused to a hinge linker comprising the amino acid sequence set forth in SEQ ID NO: 118, and wherein said hinge linker is fused to an Fc domain comprising the amino acid sequence of SEQ ID NO: 43. 
     
     
         44 . The isolated hybrid ActRIIB ligand trap protein of  claim 42 , wherein said hybrid soluble ActRIIB-ECD polypeptide comprises the amino acid sequence of SEQ ID NO: 29, wherein said hybrid soluble ActRIIB-ECD polypeptide is fused to a peptide linker comprising the amino acid sequence set forth in SEQ ID NO: 44, wherein said peptide linker is fused to a hinge linker comprising the amino acid sequence set forth in SEQ ID NO: 118, and wherein said hinge linker is fused to an Fc domain comprising the amino acid sequence of SEQ ID NO: 43. 
     
     
         45 . A pharmaceutical composition comprising a therapeutically effective amount of the hybrid ActRIIB ligand trap protein of  claim 40  in admixture with a pharmaceutically acceptable carrier. 
     
     
         46 . The pharmaceutical composition of  claim 45 , wherein said pharmaceutical composition further comprises a second agent, wherein said second agent is selected from the group consisting of: growth hormone, ghrelin, IGF1, insulin, prednisone, corticosteroid therapy, androgen-deprivation therapy, anabolic steroids, antagonists to angiotensin or angiotensin receptor, antagonists to inflammatory cytokines such as TNF-alpha, IL-6, IL-1 and their receptors, and other antagonists to myostatin, activin A or another member of the TGF-beta family and to their receptors, bisphosphonates, RANKL inhibitors, agonists of peroxisome proliferator-activated receptors, β2 agonists, activator of PGC-1alpha, proteasome inhibitors, cancer therapeutics, chemotherapeutic agents, cell therapy, stem cell therapy, gene therapy, gene targeting therapy, and antisense oligonucleotide therapy. 
     
     
         47 . A method of treating or preventing muscle wasting in a subject comprising administering to said subject a therapeutically effective amount of the pharmaceutical composition of  claim 45 , wherein the muscle wasting is associated with a condition selected from the group consisting of muscular dystrophy, myositis, myopathy, motoneuron disease, muscle atrophy, spinal muscular atrophy, neuromuscular junction disease, peripheral nerve disease, spinal cord injury, stroke, neurodegenerative disease, anorexia, cancer, organ failure, trauma, disuse, exposure to microgravity, infection, chronic obstructive pulmonary disease (COPD), sarcopenia, sarcopenic obesity, osteroarthritis and aging. 
     
     
         48 . The method according to  claim 47 , wherein said spinal muscular atrophy is selected from the group consisting of infantile progressive spinal muscular atrophy, intermediate spinal muscular atrophy, juvenile spinal muscular atrophy and adult spinal muscular atrophy. 
     
     
         49 . The method according to  claim 47 , wherein said peripheral nerve disease is selected from the group consisting of Charcot-Marie Tooth disease, Dejerine-Sottas disease and Friedreich's ataxia. 
     
     
         50 . The method according to  claim 47 , wherein said neurodegenerative disease is selected from the group consisting of Parkinson's disease, Huntington's disease, Alzheimer's disease and Creutzfeldt-Jakob disease. 
     
     
         51 . The method according to  claim 47 , wherein said aging condition is selected from the group consisting of: frailty of the elderly, age-related sarcopenia, and osteoarthritis. 
     
     
         52 . The method according to  claim 47 , wherein said motorneuron disease is amyotrophic lateral sclerosis (ALS or Lou Gehrig's Disease). 
     
     
         53 . A method of treating or preventing bone disease in a subject comprising administering to said subject a therapeutically effective amount of the pharmaceutical composition of  claim 45 , wherein the bone disease is selected from the group consisting of: osteoporosis, renal osteodystrophy, osteomalacia, osteogenesis imperfecta, fibrodysplasia ossificans progressiva, corticosteroid-induced bone loss, androgen-deprivation therapy-induced bone loss, bone fracture, cancer-induced bone loss, bone metastasis, Paget's disease of the bone, Rickets, Perthes' disease and fibrous dysplasia. 
     
     
         54 . The method according to  claim 47 , comprising further administering to said subject a second agent, wherein said second agent is selected from the group consisting of: gene therapy, gene targeting therapy, and antisense oligonucleotide therapy. 
     
     
         55 . The method according to  claim 54 , wherein the second agent is administered to the subject at least once prior to the first administration of the pharmaceutical composition comprising the hybrid ActRIIB ligand trap protein. 
     
     
         56 . A polynucleotide encoding a protein comprising:
 a) A hybrid soluble ActRIIB-ECD polypeptide sequence selected from the group consisting of SEQ ID NO: 16 and SEQ ID NO: 29, and   b) A polypeptide sequence of an Fc domain of a human immunoglobulin.   
     
     
         57 . A vector comprising the polynucleotide of  claim 56 . 
     
     
         58 . A host cell comprising the polynucleotide of  claim 56 . 
     
     
         59 . A method of producing a hybrid ActRIIB protein comprising culturing the host cell of  claim 58  under conditions promoting the expression of the protein, and recovering the protein.