WO2023179791A9

WO2023179791A9 - Treatment of musculoskeletal disorders

Info

Publication number: WO2023179791A9
Application number: PCT/CN2023/083898
Authority: WO
Inventors: Xiaofeng Liu; Kunfeng LIU; Baozhi Yuan; Muyu LI; Hua Zhu Ke
Original assignee: Angitia Biomedicines Limited
Priority date: 2022-03-24
Filing date: 2023-03-24
Publication date: 2023-10-26
Also published as: WO2023179791A1

Abstract

Provided are novel treatment molecules for musculoskeletal disorders, wherein the molecules include a bone anabolic agent like anti-Sclerostin constructs that bind to Sclerostin (e.g., anti-Sclerostin antibodies) and bone resorption inhibitors. Also provided are the amino acid sequences and methods of preparing such treatment molecules, pharmaceutical compositions containing the treatment molecules, and methods of using such molecules or compositions.

Description

TREATMENT OF MUSCULOSKELETAL DISORDERS

CROSS-REFERENCE TO RELATED APPLICATION

[Rectified under Rule 91, 05.09.2023]
This application claims priority to International Application No. PCT/CN2022/082878, filed on March 24, 2022, the content of which is incorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

The present disclosure relates to treatment of musculoskeletal disorders, bispecific constructs (such as anti-Sclerostin and anti-RANKL bispecific antibodies) and the uses thereof.

SUBMISSION OF SEQUENCE LISTING ON ASCII TEXT FILE

The content of the following submission on XML file is incorporated herein by reference in its entirety: a computer readable form (CRF) of the Sequence Listing (file name: MTP220153-1.seqlist. xml, date recorded: March 24, 2023, size: 50.1 bytes) .

BACKGROUND OF THE APPLICATION

The function of the SOST gene product, Sclerostin, as an inhibitor of bone formation in humans was discovered by genetic mapping studies that pinpointed loss-of-function mutations in the SOST gene as causative in the high bone mass (HBM) disorder sclerosteosis. In mice, deletion of the SOST gene causes an increase in bone mass and strength due to increased bone formation, while overexpression of a human Sclerostin transgene result in low bone mass and decreased bone strength.

The disclosures of all publications, patents, patent applications and published patent applications referred to herein are hereby incorporated herein by reference in their entirety.

BRIEF SUMMARY OF THE APPLICATION

The following summary is illustrative only and is not intended to be limiting in any way. That is, the following summary is provided to introduce highlights, benefits and advantages of the novel molecules and the uses thereof. Thus, the following summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.

The present application in one aspect provides bispecific constructs comprising an antibody moiety that specifically recognizes Sclerostin (such as human Sclerostin) , and a second moiety that specifically recognizes RANKL, wherein the molar ratio of the first antibody moiety and the second antibody moiety is higher than 1: 1. In some embodiments, the molar ratio of the first antibody moiety and the second antibody moiety is from 2: 1 to 5: 1; preferably 2: 1 or 3: 1. In some embodiments, the antibody moiety is an antibody or antigen-binding fragment thereof selected from the group consisting of a full-length antibody, a bispecific antibody, a single-chain Fv (scFv) fragment, a Fab fragment, a Fab’ fragment, a F (ab’) ₂, an Fv fragment, a disulfide stabilized Fv fragment (dsFv) , a dsscFv, a (dsFv) ₂, a Fv-Fc fusion, a scFv-Fc fusion, a scFv-Fv fusion, a diabody, a tribody, and a tetrabody. In some embodiments, the construct is a full-length antibody comprising an Fc fragment. In some embodiments, the antibody moiety is a scFv fragment. In some embodiments, the second moiety comprises a half-life extending moiety (such as an Fc fragment) . In some embodiments, the second moiety comprises an agent selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , a bisphosphonate, prostaglandin E (PGE) receptor agonists, Vascular endothelial growth factor (VEGF) , transforming growth factor-β (TGFβ) , growth factor (myostatin) and calcitonin. In some embodiments, the second moiety comprises a second antibody moiety that specifically recognizes an antigen. In some embodiments, there is provided bispecific constructs comprising a first antibody moiety that specifically recognizes Sclerostin (including but not limited to anti-Sclerostin antibody moieties described herein) , and a second antibody moiety that specifically recognizes receptor activator of nuclear factor kappa beta ligand (RANKL) . Antibody moieties that recognize RANKL can be any anti-RANKL antibody moiety (including but not limited to those described herein) . In some embodiments, the second antibody moiety is a full-length antibody, a Fab, a Fab’ , a (Fab’) ₂, an Fv, a single chain Fv (scFv) fragment, a scFv-scFv, a minibody, a diabody, or an sdAb. In some embodiments, the second antibody moiety is a full-length antibody comprising an Fc fragment, and wherein the anti-Sclerostin antibody moiety is a single chain Fv (scFv) fragment. In some embodiments, the second antibody moiety is a scFv fragment, and wherein the anti-Sclerostin antibody moiety is a full-length antibody comprising an Fc fragment. In some embodiments, the scFv fragment is fused to (e.g., N-terminus and/or C-terminus of) both of the heavy chains and/or light chains of the full-length antibody (via a linker or without a linker) . In some embodiments, the construct comprises: a) a first polypeptide comprising a first light chain comprising, from N-terminus to C-terminus, i) the V_L, ii) a first light chain constant domain ( “first CL domain” ) ; b) a second polypeptide comprising a first heavy chain comprising, from N-terminus to C-terminus, i) the V_H, ii) a first heavy chain constant domain ( “first CH1 domain” ) , and iii) a first Fc domain; or i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a second Fc domain; and iv) a scFv fragment comprising the V_H and the V_L; c) a third polypeptide comprising a second heavy chain comprising, from N-terminus to C-terminus, i) the V_H-2, ii) a second heavy chain constant domain ( “second CH1 domain” ) , and iii) a second Fc domain; and d) a fourth polypeptide comprising a second light chain comprising, from N-terminus to C-terminus, i) the V_L-2, ii) a second light chain constant domain ( “second CL domain” ) , wherein the first and the second Fc domains form an Fc fragment. The first or second CH1 and/or the first or second Fc domain may have various modifications as described herein. In some embodiments, the construct comprises: a) a first and second polypeptide comprising a common light chain comprising, from N-terminus to C-terminus, i) a light chain variable region (V_L) , ii) a light chain constant domain; b) a third polypeptide comprising a first heavy chain comprising, from N-terminus to C-terminus, i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a first Fc domain, iv) a heavy chain variable region (V_H) , and v) a heavy chain constant domain; or i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a heavy chain variable region (V_H) , iv) a heavy chain constant domain, v) a first Fc domain; c) a fourth polypeptide comprising a second heavy chain comprising, from N-terminus to C-terminus, i) the V_H-2, ii) a heavy chain constant domain, and iii) a second Fc domain; or i) the V_H-2, ii) a heavy chain constant domain, and iii) a second Fc domain, iv) a heavy chain variable region (V_H) , and v) a heavy chain constant domain; d) a fifth polypeptide comprising a second light chain comprising, from N-terminus to C-terminus, i) the V_L-2, ii) a light chain constant domain; wherein the first and the second Fc domains form an Fc fragment. The first or second CH1 and/or the first or second Fc domain may have various modifications as described herein.

The present application in another aspect provides bispecific constructs that specifically bind to Sclerostin competitively with any of the bispecific constructs described herein.

The present application in another aspect provides pharmaceutical compositions comprising any of the bispecific constructs described herein and a pharmaceutically acceptable carrier. In some embodiments, the composition further comprises an agent selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , VEGF, TGFβ, growth factor (myostatin) and calcitonin.

The present application in another aspect provides isolated nucleic acids encoding any of the bispecific constructs described herein or a portion thereof (e.g., one or more polypeptides thereof) .

The present application in another aspect provides vectors comprising any of the isolated nucleic acids described herein.

The present application in another aspect provides isolated host cells comprising any of the isolated nucleic acids and/or any of the vectors described herein.

The present application in another aspect provides methods of producing a bispecific construct comprising: a) culturing any of the isolated host cells described herein under conditions effective to express the bispecific construct or a portion thereof (e.g., one or more polypeptides thereof) ; and b) obtaining the expressed bispecific construct or a portion thereof from the host cells.

The present application in another aspect provides methods of treating a disease or condition in an individual, comprising administering to the individual an effective mount of a bispecific construct such as any of the bispecific constructs described herein, or any of the pharmaceutical compositions described herein. In some embodiments, the disease or condition is a bone-related disorder. In some embodiments, the bone-related disorder is osteogenesis imperfecta, osteopetrosis, osteoporosis (in men and/or women) , senile osteoporosis, delay bone healing, delayed or non-union bone fractures, Paget’s disease, immobilization-induced bone loss, glucocorticoid-induced bone loss, inflammation-induced bone loss including arthritis-induced bone loss or other disease or condition associated with a) bone loss of either quantity or quality or both and/or b) abnormality of bone structure and quality. In some embodiments, the bispecific construct or the pharmaceutical composition is administered parenterally into the individual. In some embodiments, the method further comprises administering a second agent or therapy (e.g., an anti-RANKL antibody) . In some embodiments, the second agent or therapy comprises an agent selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , a bisphosphonate, a prostaglandin E (PGE) receptor agonist, VEGF, and TGFβ, growth factor (myostatin) and calcitonin. In some embodiments, the individual is a human.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the sequences and conformation ‘IGRGKWWR’ motif on the second loop of Sclerostin to illustrate the interaction between Sclerostin and LDL Receptor Related Protein 6 (LRP6) .

FIG. 2 shows schematic diagrams of exemplary bispecific antibody structures.

DETAILED DESCRIPTION OF THE APPLICATION

The present application provides novel bispecific constructs that specifically bind to Sclerostin and other antigen (such as anti-Sclerostin and anti-RANKL antibodies or multispecific antibodies) , methods of preparing the bispecific constructs, methods of using the constructs (e.g., methods of treating a disease or condition) . The exemplary bispecific constructs described herein achieved advantageous effects.

I. Definitions

The term “antibody” is used in its broadest sense and encompasses various antibody structures, including but not limited to monoclonal antibodies, polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies) , full-length antibodies and antigen-binding fragments thereof, so long as they exhibit the desired antigen-binding activity. The term “antibody moiety” refers to a full-length antibody or an antigen-binding fragment thereof.

[Rectified under Rule 91, 05.09.2023]
A full-length antibody comprises two heavy chains and two light chains. The variable regions of the light and heavy chains are responsible for antigen binding. The variable domains of the heavy chain and light chain may be referred to as “V_H” and “V_L” , respectively. The variable regions in both chains generally contain three highly variable loops called the complementarity determining regions (CDRs) (light chain (LC) CDRs including LC-CDR1, LC-CDR2, and LC-CDR3, heavy chain (HC) CDRs including HC-CDR1, HC-CDR2, and HC-CDR3) . CDR boundaries for the antibodies and antigen-binding fragments disclosed herein may be defined or identified by the conventions of Kabat, Chothia, or Al-Lazikani. The three CDRs of the heavy or light chains are interposed between flanking stretches known as framework regions (FRs) , which are more highly conserved than the CDRs and form a scaffold to support the hypervariable loops. The constant regions of the heavy and light chains are not involved in antigen binding, but exhibit various effector functions. Antibodies are assigned to classes based on the amino acid sequence of the constant region of their heavy chain. The five major classes or isotypes of antibodies are IgA, IgD, IgE, IgG, and IgM, which are characterized by the presence of α, δ, ε, γ, and μ heavy chains, respectively. Several of the major antibody classes are divided into subclasses such as IgG1 (γ1 heavy chain) , IgG2 (γ2 heavy chain) , IgG3 (γ3 heavy chain) , IgG4 (γ4 heavy chain) , IgA1 (α1 heavy chain) , or IgA2 (α2 heavy chain) .

The term “antigen-binding fragment” as used herein refers to an antibody fragment including, for example, a diabody, a Fab, a Fab’ , a F (ab’) 2, an Fv fragment, a disulfide stabilized Fv fragment (dsFv) , a (dsFv) ₂, a bispecific dsFv (dsFv-dsFv’) , a disulfide stabilized diabody (ds diabody) , a single-chain Fv (scFv) , a dsscFv, an scFv dimer (bivalent diabody) , a multispecific antibody formed from a portion of an antibody comprising one or more CDRs, a camelized single domain antibody, a nanobody, a domain antibody, a bivalent domain antibody, or any other antibody fragment that binds to an antigen but does not comprise a complete antibody structure. An antigen-binding fragment is capable of binding to the same antigen to which the parent antibody or a parent antibody fragment (e.g., a parent scFv) binds. In some embodiments, an antigen-binding fragment may comprise one or more CDRs from a particular human antibody grafted to a framework region from one or more different human antibodies.

“Fv” is the minimum antibody fragment, which contains a complete antigen-recognition and -binding site. This fragment consists of a dimer of one heavy-and one light-chain variable region domain in tight, non-covalent association. From the folding of these two domains emanate six hypervariable loops (3 loops each from the heavy and light chain) that contribute the amino acid residues for antigen binding and confer antigen binding specificity to the antibody. However, even a single variable domain (or half of an Fv comprising only three CDRs specific for an antigen) has the ability to recognize and bind antigen, although at a lower affinity than the entire binding site.

“Single-chain Fv, ” also abbreviated as “sFv” or “scFv, ” are antibody fragments that comprise the V_H and V_L antibody domains connected into a single polypeptide chain. In some embodiments, the scFv polypeptide further comprises a polypeptide linker between the V_H and V_L domains which enables the scFv to form the desired structure for antigen binding.

As used herein, the term “CDR” or “complementarity determining region” is intended to mean the non-contiguous antigen combining sites found within the variable region of both heavy and light chain polypeptides. Nevertheless, application of either definition to refer to a CDR of an antibody or grafted antibodies or variants thereof is intended to be within the scope of the term as defined and used herein. The amino acid residues which encompass the CDRs as defined by each of the above-cited references are set forth below in Table 1 as a comparison. The contents of the references cited in this paragraph are incorporated herein by reference in their entireties for use in the present application and for possible inclusion in one or more claims herein. In some embodiments, the CDR sequences provided herein are based on IMGT definition. For example, the CDR sequences may be determined by the VBASE2 tool (http: //www. vbase2. org/vbase2. php.

The term “osteoporosis” as used herein refers to premenopausal idiopathic osteoporosis, postmenopausal osteoporosis, menopausal osteoporosis, postoophorectomy osteoporosis, osteoporosis of disuse, drug-induced osteoporosis, osteoporosis due to malabsorption, post-surgical malabsorption osteoporosis and/or senile osteoporosis.

The term “osteopenia” as used herein refers to premenopausal idiopathic osteopenia, postmenopausal osteopenia, senile osteopenia, drug-induced osteopenia, osteopenia of disuse, neonatal osteopenia and/or spaceflight osteopenia caused by reduced gravity.

The term “metabolic bone diseases” as used herein includes but not limit to renal osteodystrophy, primary and secondary hyperparathyroidism, familial hyperparathyroidism syndromes, parathyroid disorders, osteodystrophy, osteochondrosis, hyperphosphatasia.

The term “osteonecrosis” as used herein refers to avascular necrosis of bone, avascular necrosis secondary to diving, osteonecrosis of jaw.

The term “bone loss” as used herein refers to postmenopausal bone loss, Immobilization-induced bone loss, Weightlessness induced bone loss, Disease associated facial bone loss, Disease associated cranial bone loss, Disease associated bone loss of the jaw, Disease associated bone loss of the skull, bone loss associated with space travel, glucocorticoid-induced bone loss, Drug-induced bone loss, Organ transplant related bone loss, Kidney transplant related bone loss, HIV associated bone loss, bone loss associated with loss of growth hormone, bone loss associated with cystic fibrosis, Chemotherapy associated bone loss, Tumor induced bone loss, Cancer-related bone loss, Hormone ablative bone loss, Oral bone loss, Heparin-induced bone loss, Inflammation-induced bone loss including arthritis-induced bone loss or other disease or condition associated with a) bone loss of either quantity or quality or both and/or b) abnormality of bone structure and quality. bone loss caused by reduced gravity.

The term “nonunion” or “delay bone healing” as used herein refers to delayed or non-union bone fractures, hip fracture, pseudoarthritis after fusion or arthrodesis, osteolysis, postsurgical osteolysis, nonunion after spinal arthrodesis, enhancement/acceleration of spinal fusion, chronic pain after arthroplasty.

The term “osteomalacia” as used herein refers to Vitamin-D-resistant osteomalacia, calcium deficiency, sarcopenia, cancer sarcopenia, tumor-induced osteomalacia.

The term “fracture” as used herein includes but not limited to compression fracture, fragility fracture, pathologic fracture, stress fracture, hip fracture, fracture of femoral neck, atypical hip fracture, femoral intertrochanter fracture, fracture of bone in neoplastic disease.

The term “hypercalcemia” as used herein includes hypercalcemia of malignancy, myopathy due to hypercalcemia, hypercalcemia in chronic kidney disease.

The term “multiple myeloma related bone disorders” as used herein refers to multiple myeloma bone disease and ore osteoporosis in multiple myelomatosis.

The term “primary bone tumor” as used herein includes osteosarcoma, osteochondroma, osteoblastoma, osteochondromyxoma, osteoclastoma, osteoma, osteoid osteoma, chondrosarcoma, chondroblastoma, chondromyxoid fibroma, myxoid chondrosarcoma, sarcoma, ewing sarcoma, kaposi sarcoma, periosteal sarcoma, glomangiosarcoma, giant cell tumor, giant cell sarcoma, giant cell angiofibroma, haemangioendothelial sarcoma, undifferentiated sarcoma, fibrosarcoma, bone cyst, aneurysmal bone cyst, multiple endocrine neoplasia.

The term “malignancies” for “bone metastasis of malignancies” includes breast cancer, lung cancer, hepatic cancer, ovarian cancer, pancreatic cancer, colorectal cancer, gastric cancer, prostate cancer, thyroid cancer, thymus cancer.

The term “inflammatory or infectious bone disease” as used herein refers to osteomyelitis, pyogenic osteomyelitis, ankylosing spondylitis.

The term “bone marrow or haemotological disordersdiseases” as used herein refers to leukemia, malignant lymphoma, haematological malignancy, haematologic disease, bone marrow disease.

The term “musculoskeletal rare disease” as used herein includes Osteogenesis imperfecta, Albers-Schonberg disease, congenital pseudarthrosis of the tibia, enchondromatosis, fibrous dysplasia, Gaucher's Disease, Marfan's syndrome, multiple hereditary exotoses, neurofibromatosis, osteogenesis imperfecta, osteopetrosis, osteopoikilosis, sclerotic lesions, pseudoarthrosis, , melorheostosis, Juvenile arthritides, thalassemia, mucopolysaccharidoses, turner syndrome, Pown Syndrome, Klinefelter Syndrome, leprosy, Perthes'Disease, adolescent idiopathic scoliosis, Winchester Syndrome, Menkes Disease, ischemic bone disease (such as Legg-Calve-Perthes disease, regional migratory osteoporosis) , Idiopathic infantile hypercalcemia, Acromegaly, Hypogonadism, Albright-McCune-Sternberg syndrome, Aluminium bone disease, Camurati-Engelmann disease, Osteopetrosis and infantile neuroaxonal dystrophy, Dysosteosclerosis, Pycnodysostosis, Gorham-Stout syndrome, Cystic angiomatosis, Paget’s disease, Juvenile Paget's disease, Osteoporosis-oculocutaneous-hypopigmentation syndrome, Osteoporosis in classical or atypical cystic fibrosis, Bowed tibiae-radial anomalies-osteopenia-fractures, X-linked hypophosphatemic osteomalacia, Familial expansile osteolysis, Osteopoikilosis, Melorheostosis, Craniometaphyseal dysplasia, Osteoporosis-pseudoglioma syndrome, Cleidocranial dysplasia, Hajdu-Cheney syndrome, Winchester-Torg syndrome, Cole-Carpenter syndrome, Hypophosphatasia, Hereditary hyperphosphatasia, Fibrodysplasia ossificans progressive, Familial hypocalciuric hypercalcemia, Pseudohypoparathyroidism, Acrodysostosis, Eiken syndrome, Multiple enchondromatosis, Vitamin D hydroxylation–deficient rickets, Hypophosphatemic rickets.

The term “cartilage-related disorder” as used herein includes but not limited to Chondromatosis, Chondrodysplasia, Chondrodystrophic myotonia, Juxtacortical chondroma, Tear of cartilage of knee, Osteoarthritis, Osteochondrodystrophy.

The term “muscle-related disorder” as used herein includes sarcopenia and cancer sarcopenia.

The term “surgeries” as used in “facilitation of heal after bone or joint surgeries” refers to orthopedic procedures, dental procedures, implant surgery, joint replacement, joint-preserving surgery, distraction osteogenesis, bone lengthening, bone grafting, bone cosmetic surgery and bone repair such as fracture healing, nonunion healing, delayed union healing and facial reconstruction.

TABLE 1: CDR DEFINITIONS

The expression “variable-domain residue-numbering as in Kabat” or “amino-acid-position numbering as in Kabat, ” and variations thereof, refers to the numbering system used for heavy-chain variable domains or light-chain variable domains of the compilation of antibodies in Kabat numbering scheme system. Using this numbering system, the actual linear amino acid sequence may contain fewer or additional amino acids corresponding to a shortening of, or insertion into, a FR or hypervariable region (HVR) of the variable domain. For example, a heavy-chain variable domain may include a single amino acid insert (residue 52a according to Kabat) after residue 52 of H2 and inserted residues (e.g. residues 82a, 82b, and 82c, etc. according to Kabat) after heavy-chain FR residue 82. The Kabat numbering of residues may be determined for a given antibody by alignment at regions of homology of the sequence of the antibody with a “standard” Kabat numbered sequence.

Unless indicated otherwise herein, the numbering of the residues in an immunoglobulin heavy chain is that of the EU index as in Kabat numbering scheme. The “EU index as in Kabat” refers to the residue numbering of the human IgG1 EU antibody.

“Framework” or “FR” residues are those variable-domain residues other than the CDR residues as herein defined.

“Humanized” forms of non-human (e.g., rodent) antibodies are chimeric antibodies that contain minimal sequence derived from the non-human antibody. For the most part, humanized antibodies are human immunoglobulins (recipient antibody) in which residues from a hypervariable region (HVR) of the recipient are replaced by residues from a hypervariable region of a non-human species (donor antibody) such as mouse, rat, rabbit or non-human primate having the desired antibody specificity, affinity, and capability. In some instances, framework region (FR) residues of the human immunoglobulin are replaced by corresponding non-human residues. Furthermore, humanized antibodies can comprise residues that are not found in the recipient antibody or in the donor antibody. These modifications are made to further refine antibody performance. In general, 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 FRs are those of a human immunoglobulin sequence. The humanized antibody optionally also will comprise at least a portion of an immunoglobulin constant region (Fc) , typically that of a human immunoglobulin.

A “human antibody” is an antibody that possesses an amino-acid sequence corresponding to that of an antibody produced by a human and/or has been made using any of the techniques for making human antibodies as disclosed herein. This definition of a human antibody specifically excludes a humanized antibody comprising non-human antigen-binding residues. Human antibodies can be prepared by administering the antigen to a transgenic animal that has been modified to produce such antibodies in response to antigenic challenge, but whose endogenous loci have been disabled, e.g., immunized xenomice.

“Percent (%) amino acid sequence identity” or “homology” with respect to the polypeptide and antibody sequences identified herein is defined as the percentage of amino acid residues in a candidate sequence that are identical with the amino acid residues in the polypeptide being compared, after aligning the sequences considering any conservative substitutions as part of the sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN, Megalign (DNASTAR) , or MUSCLE software. Those skilled in the art can determine appropriate parameters for measuring alignment, including any algorithms needed to achieve maximal alignment over the full-length of the sequences being compared. For purposes herein, however, %amino acid sequence identity values are generated using the sequence comparison computer program MUSCLE.

“Homologous” refers to the sequence similarity or sequence identity between two polypeptides or between two nucleic acid molecules. When a position in both of the two compared sequences is occupied by the same base or amino acid monomer subunit, e.g., if a position in each of two DNA molecules is occupied by adenine, then the molecules are homologous at that position. The percent of homology between two sequences is a function of the number of matching or homologous positions shared by the two sequences divided by the number of positions compared times 100. For example, if 6 of 10 of the positions in two sequences are matched or homologous then the two sequences are 60%homologous. By way of example, the DNA sequences ATTGCC and TATGGC share 50%homology. Generally, a comparison is made when two sequences are aligned to give maximum homology.

The term “constant domain” refers to the portion of an immunoglobulin molecule having a more conserved amino acid sequence relative to the other portion of the immunoglobulin, the variable domain, which contains the antigen-binding site. The constant domain contains the C_H1, C_H2 and C_H3 domains (collectively, C_H) of the heavy chain and the CL (or C_L) domain of the light chain.

The “light chains” of antibodies (immunoglobulins) from any mammalian species can be assigned to one of two clearly distinct types, called kappa ( “κ” ) and lambda ( “λ” ) , based on the amino acid sequences of their constant domains. The CL domain of the light chain can be called CK (or C_κ) an CL (or C_λ) , respectively.

The “C_H1 domain” (also referred to as “C1” of “H1” domain) usually extends from about amino acid 118 to about amino acid 215 (EU numbering system) .

“Hinge region” is generally defined as a region in IgG corresponding to Glu216 to Pro230 of human IgG1. Hinge regions of other IgG isotypes may be aligned with the IgG1 sequence by placing the first and last cysteine residues forming inter-heavy chain S-S bonds in the same positions.

The “C_H2 domain” of a human IgG Fc region (also referred to as “C2” domain) usually extends from about amino acid 231 to about amino acid 340. The C_H2 domain is unique in that it is not closely paired with another domain. Rather, two N-linked branched carbohydrate chains are interposed between the two C_H2 domains of an intact native IgG molecule. It has been speculated that the carbohydrate may provide a substitute for the domain-domain pairing and help stabilize the CH2 domain.

The “C_H3 domain” (also referred to as “C3” domain) comprises the stretch of residues C-terminal to a C_H2 domain in an Fc region (i.e. from about amino acid residue 341 to the C-terminal end of an antibody sequence, typically at amino acid residue 446 or 447 of an IgG) .

The term “Fc region” or “fragment crystallizable region” herein is used to define a C-terminal region of an immunoglobulin heavy chain, including native-sequence Fc regions and variant Fc regions. Although the boundaries of the Fc region of an immunoglobulin heavy chain might vary, the human IgG heavy-chain Fc region is usually defined to stretch from an amino acid residue at position Cys226, or from Pro230, to the carboxyl-terminus thereof. The C-terminal lysine (residue 447 according to the EU numbering system) of the Fc region may be removed, for example, during production or purification of the antibody, or by recombinantly engineering the nucleic acid encoding a heavy chain of the antibody. Accordingly, a composition of intact antibodies may comprise antibody populations with all K447 residues removed, antibody populations with no K447 residues removed, and antibody populations having a mixture of antibodies with and without the K447 residue. Suitable native-sequence Fc regions for use in the antibodies described herein include human IgG1, IgG2 (IgG2A, IgG2B) , IgG3 and IgG4.

“Fc receptor” or “FcR” describes a receptor that binds the Fc region of an antibody. The preferred FcR is a native sequence human FcR. Moreover, a preferred FcR is one which binds an IgG antibody (a gamma receptor) and includes receptors of the FcγRI, FcγRII, and FcγRIII subclasses, including allelic variants and alternatively spliced forms of these receptors, FcγRII receptors include FcγRIIA (an “activating receptor” ) and FcγRIIB (an “inhibiting receptor” ) , which have similar amino acid sequences that differ primarily in the cytoplasmic domains thereof. Activating receptor FcγRIIA contains an immunoreceptor tyrosine-based activation motif (ITAM) in its cytoplasmic domain. Inhibiting receptor FcγRIIB contains an immunoreceptor tyrosine-based inhibition motif (ITIM) in its cytoplasmic domain. Other FcRs, including those to be identified in the future, are encompassed by the term “FcR” herein.

The term “epitope” as used herein refers to the specific group of atoms or amino acids on an antigen to which an antibody or antibody moiety binds. Two antibodies or antibody moieties may bind the same epitope within an antigen if they exhibit competitive binding for the antigen.

As used herein, a first antibody or fragment thereof “competes” for binding to a target antigen with a second antibody or fragment thereof when the first antibody or fragment thereof inhibits the target antigen binding of the second antibody of fragment thereof by at least about 50%(such as at least about any one of 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%or 99%) in the presence of an equimolar concentration of the first antibody or fragment thereof, or vice versa. A high throughput process for “binning” antibodies based upon their cross-competition is described in PCT Publication No. WO 03/48731.

As use herein, the terms “specifically binds, ” “specifically recognizing, ” and “is specific for” refer to measurable and reproducible interactions, such as binding between a target and an antibody or antibody moiety, which is determinative of the presence of the target in the presence of a heterogeneous population of molecules, including biological molecules. For example, an antibody or antibody moiety that specifically recognizes a target (which can be an epitope) is an antibody or antibody moiety that binds this target with greater affinity, avidity, more readily, and/or with greater duration than its bindings to other targets. In some embodiments, the extent of binding of an antibody to an unrelated target is less than about 10%of the binding of the antibody to the target as measured, e.g., by a radioimmunoassay (RIA) . In some embodiments, an antibody that specifically binds a target has a dissociation constant (K_D) of ≤10^-5 M, ≤10^-6 M, ≤10^-7 M, ≤10^- ⁸ M, ≤10^-9 M, ≤10^-10 M, ≤10^-11 M, or ≤10^-12 M. In some embodiments, an antibody specifically binds an epitope on a protein that is conserved among the protein from different species. In some embodiments, specific binding can include, but does not require exclusive binding. Binding specificity of the antibody or antigen-binding domain can be determined experimentally by methods known in the art. Such methods comprise, but are not limited to Western blots, ELISA-, RIA-, ECL-, IRMA-, EIA-, BLI-, BIACORE^TM -tests and peptide scans.

An “isolated” antibody (or construct) is one that has been identified, separated and/or recovered from a component of its production environment (e.g., natural or recombinant) . Preferably, the isolated polypeptide is free of association with all other components from its production environment.

An “isolated” nucleic acid molecule encoding a construct, antibody, or antigen-binding fragment thereof described herein is a nucleic acid molecule that is identified and separated from at least one contaminant nucleic acid molecule with which it is ordinarily associated in the environment in which it was produced. Preferably, the isolated nucleic acid is free of association with all components associated with the production environment. The isolated nucleic acid molecules encoding the polypeptides and antibodies described herein is in a form other than in the form or setting in which it is found in nature. Isolated nucleic acid molecules therefore are distinguished from nucleic acid encoding the polypeptides and antibodies described herein existing naturally in cells. An isolated nucleic acid includes a nucleic acid molecule contained in cells that ordinarily contain the nucleic acid molecule, but the nucleic acid molecule is present extrachromosomally or at a chromosomal location that is different from its natural chromosomal location.

Nucleic acid is “operably linked” when it is placed into a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. Generally, “operably linked” means that the DNA sequences being linked are contiguous, and, in the case of a secretory leader, contiguous and in reading frame. However, enhancers do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, the synthetic oligonucleotide adaptors or linkers are used in accordance with conventional practice.

The term “vector, ” as used herein, refers to a nucleic acid molecule capable of propagating another nucleic acid to which it is linked. The term includes the vector as a self-replicating nucleic acid structure as well as the vector incorporated into the genome of a host cell into which it has been introduced. Certain vectors are capable of directing the expression of nucleic acids to which they are operatively linked. Such vectors are referred to herein as “expression vectors. ”

The term “transfected” or “transformed” or “transduced” as used herein refers to a process by which exogenous nucleic acid is transferred or introduced into the host cell. A “transfected” or “transformed” or “transduced” cell is one which has been transfected, transformed or transduced with exogenous nucleic acid. The cell includes the primary subject cell and its progeny.

The terms “host cell, ” “host cell line, ” and “host cell culture” are used interchangeably and refer to cells into which exogenous nucleic acid has been introduced, including the progeny of such cells. Host cells include “transformants” and “transformed cells, ” which include the primary transformed cell and progeny derived therefrom without regard to the number of passages. Progeny may not be completely identical in nucleic acid content to a parent cell, and may contain mutations. Mutant progeny that has the same function or biological activity as screened or selected for in the originally transformed cell are included herein.

As used herein, “treatment” or “treating” is an approach for obtaining beneficial or desired results, including clinical results. For purposes of this application, beneficial or desired clinical results include, but are not limited to, one or more of the following: alleviating one or more symptoms resulting from the disease, diminishing the extent of the disease, stabilizing the disease, preventing or delaying the spread of the disease, preventing or delaying the recurrence of the disease, delaying or slowing the progression of the disease, ameliorating the disease state, providing a remission (partial or total) of the disease, decreasing the dose of one or more other medications required to treat the disease, delaying the progression of the disease, increasing or improving the quality of life, increasing weight gain, and/or prolonging survival. The methods of the application contemplate any one or more of these aspects of treatment.

The terms “inhibition” or “inhibit” refer to a decrease or cessation of any phenotypic characteristic or to the decrease or cessation in the incidence, degree, or likelihood of that characteristic. To “reduce” or “inhibit” is to decrease, reduce or arrest an activity, function, and/or amount as compared to that of a reference. In certain embodiments, by “reduce” or “inhibit” is meant the ability to cause an overall decrease of 20%or greater. In another embodiment, by “reduce” or “inhibit” is meant the ability to cause an overall decrease of 50%or greater. In yet another embodiment, by “reduce” or “inhibit” is meant the ability to cause an overall decrease of 75%, 85%, 90%, 95%, or greater.

A “reference” as used herein, refers to any sample, standard, or level that is used for comparison purposes. A reference may be obtained from a healthy and/or non-diseased sample. In some examples, a reference may be obtained from an untreated sample. In some examples, a reference is obtained from a non-diseased or non-treated sample of an individual. In some examples, a reference is obtained from one or more healthy individuals who are not the individual or patient.

As used herein, “delaying development of a disease"means to defer, hinder, slow, retard, stabilize, suppress and/or postpone development of the disease. This delay can be of varying lengths of time, depending on the history of the disease and/or individual being treated. As is evident to one skilled in the art, a sufficient or significant delay can, in effect, encompass prevention, in that the individual does not develop the disease.

“Preventing” as used herein, includes providing prophylaxis with respect to the occurrence or recurrence of a disease in an individual that may be predisposed to the disease but has not yet been diagnosed with the disease.

As used herein, to “suppress” a function or activity is to reduce the function or activity when compared to otherwise same conditions except for a condition or parameter of interest, or alternatively, as compared to another condition. For example, an antibody which suppresses tumor growth reduces the rate of growth of the tumor compared to the rate of growth of the tumor in the absence of the antibody.

The terms “subject, ” “individual, ” and “patient” are used interchangeably herein to refer to a mammal, including, but not limited to, human, bovine, horse, feline, canine, rodent, or primate. In some embodiments, the individual is a human.

An “effective amount” of an agent refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired therapeutic or prophylactic result. The specific dose may vary depending on one or more of: the particular agent chosen, the dosing regimen to be followed, whether it is administered in combination with other compounds, timing of administration, the tissue to be imaged, and the physical delivery system in which it is carried.

The terms “pharmaceutical formulation” and “pharmaceutical composition” refer to a preparation which is in such form as to permit the biological activity of the active ingredient (s) to be effective, and which contains no additional components which are unacceptably toxic to an individual to which the formulation would be administered. Such formulations may be sterile.

A “pharmaceutically acceptable carrier” refers to a non-toxic solid, semisolid, or liquid filler, diluent, encapsulating material, formulation auxiliary, or carrier conventional in the art for use with a therapeutic agent that together comprise a “pharmaceutical composition” for administration to an individual. A pharmaceutically acceptable carrier is non-toxic to recipients at the dosages and concentrations employed and is compatible with other ingredients of the formulation. The pharmaceutically acceptable carrier is appropriate for the formulation employed. Pharmaceutically acceptable carriers or excipients have preferably met the required standards of toxicological and manufacturing testing and/or are included on the Inactive Ingredient Guide prepared by the U.S. Food and Drug administration.

A “sterile” formulation is aseptic or essentially free from living microorganisms and their spores.

Administration “in combination with” one or more further therapeutic agents includes simultaneous (concurrent) and consecutive or sequential administration in any order.

The term “concurrently” is used herein to refer to administration of two or more therapeutic agents, where at least part of the administration overlaps in time or where the administration of one therapeutic agent falls within a short period of time relative to administration of the other therapeutic agent. For example, the two or more therapeutic agents are administered with a time separation of no more than about 60 minutes, such as no more than about any of 30, 15, 10, 5, or 1 minutes.

The term “sequentially” is used herein to refer to administration of two or more therapeutic agents where the administration of one or more agent (s) continues after discontinuing the administration of one or more other agent (s) . For example, administration of the two or more therapeutic agents are administered with a time separation of more than about 15 minutes, such as about any of 20, 30, 40, 50, or 60 minutes, 1 day, 2 days, 3 days, 1 week, 2 weeks, or 1 month, or longer.

As used herein, “in conjunction with” refers to administration of one treatment modality in addition to another treatment modality. As such, “in conjunction with” refers to administration of one treatment modality before, during or after administration of the other treatment modality to the individual.

The term “package insert” is used to refer to instructions customarily included in commercial packages of therapeutic products, that contain information about the indications, usage, dosage, administration, combination therapy, contraindications and/or warnings concerning the use of such therapeutic products.

An “article of manufacture” is any manufacture (e.g., a package or container) or kit comprising at least one reagent, e.g., a medicament for treatment of a disease or disorder, or a probe for specifically detecting a biomarker described herein. In certain embodiments, the manufacture or kit is promoted, distributed, or sold as a unit for performing the methods described herein.

It is understood that embodiments of the application described herein include “consisting” and/or “consisting essentially of” embodiments.

Reference to “about” a value or parameter herein includes (and describes) variations that are directed to that value or parameter per se. For example, description referring to “about X” includes description of “X” .

The term “about X-Y” used herein has the same meaning as “about X to about Y. ”

As used herein and in the appended claims, the singular forms “a, ” “or, ” and “the” include plural referents unless the context clearly dictates otherwise.

II. Bispecific constructs (target both Sclerostin and RANKL)

The present application provides bispecific constructs comprising an anti-Sclerostin antibody moiety that specifically binds to Sclerostin (product of SOST) and an anti-RANKL antibody moiety as described herein.

The present application provides multispecific constructs targeting both Sclerostin and RANKL. In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL. In some embodiments, the Sclerostin is a human Sclerostin. In some embodiments, the RANKL is a human RANKL.

RANKL (Receptor activator of nuclear factor kappa-Β ligand) , also known as tumor necrosis factor ligand superfamily member 11 (TNFSF11) , is a ligand for osteoprotegerin and functions as a key factor for osteoclast differentiation and activation. This protein was shown to be a dendritic cell survival factor and is involved in the regulation of T cell-dependent immune response. T cell activation was reported to induce expression of this gene and lead to an increase of osteoclastogenesis and bone loss. This protein was shown to activate antiapoptotic kinase AKT/PKB through a signaling complex involving SRC kinase and tumor necrosis factor receptor-associated factor (TRAF6) , which indicated this protein may have a role in the regulation of cell apoptosis. Targeted disruption of the related gene in mice led to severe osteopetrosis and a lack of osteoclasts. The deficient mice exhibited defects in early differentiation of T and B lymphocytes, and failed to form lobulo-alveolar mammary structures during pregnancy.

Exemplary anti-RANKL antibody moieties

In some embodiments, the anti-RANKL antibody moiety (such as an scFv) used in multispecific bispecific constructs described herein comprises an antibody moiety comprising a heavy chain variable region (V_H) and a light chain variable region (V_L) , wherein the antibody moiety competes for a binding epitope of RANKL with an antibody or antibody fragment comprising a second heavy variable region (V_H-2) and a second light chain variable region (V_L-2) , wherein the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12.

In some embodiments, the anti-RANKL antibody moiety (such as an scFv or a Fab) used in multispecific bispecific constructs comprises an antibody moiety comprising a heavy chain variable region (V_H) and a light chain variable region (V_L) , wherein the V_H comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12. In some embodiments, the V_H comprises an amino acid sequence of SEQ ID NO: 13, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity; and the V_L comprises an amino acid sequence of SEQ ID NO: 14, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity.

In some embodiments, the anti-RANKL moiety comprises a HC-CDR1, a HC-CDR2, and a HC-CDR3, respectively comprising the amino acid sequences of a CDR1, a CDR2, and a CDR3 within a V_H chain region having the sequence set forth in SEQ ID NO: 13; and a LC-CDR1, a LC-CDR2, and a LC-CDR3, respectively comprising the amino acid sequences of a CDR1, a CDR2, and a CDR3 within a V_L chain region having the sequence set forth in SEQ ID NO: 14.

In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes RANKL and a second antibody moiety that specifically recognizes Sclerostin, wherein the first antibody moiety comprises an anti-RANKL single domain antibody (sdAb) moiety, and wherein the second antibody moiety comprises a full-length antibody comprising a heavy chain variable region (V_H) and a second light chain variable region (V_L) and an Fc fragment. In some embodiments, the anti-RANKL sdAb is fused to one or both of the heavy chains of the full-length antibody comprising an Fc fragment. In some embodiments, the anti-RANKL sdAb is fused to one or both of the light chains of the full-length antibody. In some embodiments, the anti-RANKL sdAb is fused to N-terminus of one or both heavy or light chains of the full-length antibody. In some embodiments, the anti-RANKL sdAb is fused to C-terminus of one or both heavy or light chains of the full-length antibody. In some embodiments, the anti-RANKL sdAb is fused to the full-length antibody via a linker (such as any of the linkers described herein) . In some embodiments, the anti-RANKL sdAb is fused to the full-length antibody without a linker.

In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes RANKL and a second antibody moiety that specifically recognizes Sclerostin, wherein the first antibody moiety comprises an anti-RANKL single domain antibody (sdAb) moiety, wherein the second antibody moiety comprises a heavy chain variable region (V_H) and a second light chain variable region (V_L) , wherein the construct comprises: a) two chimeric heavy chains each comprising, from N-terminus to C-terminus, the i) the V_H, ii) a first heavy chain constant domain ( “C_H1 domain” ) , iii) the anti-RANKL sdAb, and iv) an Fc domain, wherein the two Fc domains form an Fc fragment; b) two light chains comprising the V_L and a light chain constant domain ( “C_L domain” ) . In some embodiments, the anti-RANKL sdAb is fused to the Fc domain via a first linker. In some embodiments, the anti-RANKL sdAb is fused to the V_H via a second linker.

In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes RANKL and a second antibody moiety that specifically recognizes Sclerostin, wherein the first antibody moiety comprises an anti-RANKL single domain antibody (sdAb) moiety, wherein the second antibody moiety comprises a heavy chain variable region (V_H) and a second light chain variable region (V_L) , and wherein the construct comprises: a) a first heavy chain comprising, from N-terminus to C-terminus, i) the anti-RANKL sdAb, and ii) a first Fc domain; b) a second heavy chain comprising, from N-terminus to C-terminus, i) the V_H, ii) a first heavy chain constant domain ( “C_H1 domain” ) , and iii) a second Fc domain; and c) a light chain comprising the V_L and a light chain constant domain ( “C_L domain” ) , wherein the first and the second Fc domains form an Fc fragment.

In some embodiments, one of the first and the second Fc domains comprises a T366W mutation, and optionally a S354C mutation, and wherein the other Fc domain comprises a T366S mutation, a L368A mutation, a Y407V mutation, and optionally a Y349C mutation.

In some embodiments, wherein the second antibody moiety competes for a binding epitope of RANKL with a third antibody moiety comprising a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) , wherein the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12. In some embodiments, the V_H comprises a HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, a HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and a HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L comprises a LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, a LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and a LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12.

In some embodiments, the bispecific construct is a multispecific (e.g., bispecific) bispecific construct comprising a) an anti-Sclerostin antibody moiety according to any one of the anti-Sclerostin antibody moieties described herein; b) a second antibody moiety specifically recognizing RANKL (an anti-RANKL antibody moiety such as any of the anti-RANKL antibody moieties described herein) . In some embodiments, the anti-Sclerostin V_H comprises i) the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, ii) the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and iii) the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the HC-CDRs, and the anti-Sclerostin V_L comprises i) the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4, ii) the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and iii) the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 6, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the LC-CDRs.

In some embodiments, the anti-Sclerostin V_H comprises i) the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, ii) the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and iii) the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the HC-CDRs, and the anti-Sclerostin V_L comprises i) the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 26, ii) the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and iii) the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 6, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the LC-CDRs.

In some embodiments, the amino acid substitutions described above are limited to “exemplary substitutions” shown in Table 2 of this application. In some embodiments, the amino acid substitutions are limited to “preferred substitutions” shown in Table 2 of this application.

In some embodiments, the bispecific construct comprises a) an anti-Sclerostin full-length antibody comprising two heavy chains and two light chains, wherein the two heavy chains each comprises a heavy chain variable region (V_H) and the two light chains each comprises a light chain variable region (V_L) , b) an anti-RANKL antibody moiety (such as any of the antibody moiety described herein) fused to at least one or both of the heavy chains of the anti-Sclerostin full-length antibody. In some embodiments, the anti-RANKL antibody moiety is fused to N-terminus of one or both heavy chain. In some embodiments, the anti-RANKL antibody moiety is fused to C-terminus of one or both heavy chain.

In some embodiments, the bispecific construct comprises a) an anti-RANKL antibody moiety comprising a full-length antibody comprising two heavy chains and two light chains, wherein the two heavy chains each comprises a heavy chain variable region (V_H) and the two light chains each comprises a light chain variable region (V_L) , b) an anti-Sclerostin antibody moiety (such as any of the anti-Sclerostin antibody moiety described herein) fused to at least one or both of the heavy chains of the anti-RANKL full-length antibody. In some embodiments, the anti-Sclerostin antibody moiety is fused to N-terminus of one or both heavy chains. In some embodiments, the anti-Sclerostin antibody moiety is fused to C-terminus of one or both heavy chains.

In some embodiments, the bispecific construct comprises a) an anti-Sclerostin full-length antibody comprising two heavy chains and two light chains, wherein the two heavy chains each comprises a heavy chain variable region (V_H) and the two light chains each comprises a light chain variable region (V_L) , b) an anti-RANKL antibody moiety (such as any of the antibody moiety described herein) fused to at least one or both of the light chains of the anti-Sclerostin full-length antibody. In some embodiments, the anti-RANKL antibody moiety is fused to N-terminus of one or both light chains. In some embodiments, the anti-RANKL antibody moiety is fused to C-terminus of one or both light chains.

In some embodiments, the bispecific construct comprises a) an anti-RANKL antibody moiety comprising a full-length antibody comprising two heavy chains and two light chains, wherein the two heavy chains each comprises a heavy chain variable region (V_H) and the two light chains each comprises a light chain variable region (V_L) , b) an anti-Sclerostin antibody moiety (such as any of the antibody moiety described herein) fused to at least one or both of the light chains of the anti-RANKL full-length antibody. In some embodiments, the anti-Sclerostin antibody moiety is fused to N-terminus of one or both light chains. In some embodiments, the anti-Sclerostin antibody moiety is fused to C-terminus of one or both light chains.

In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the first antibody moiety comprises single chain Fv fragment (scFv) comprising a first heavy chain variable region (V_H-1) and a first light chain variable region (V_L-1) , and wherein the second antibody moiety is a full-length antibody comprising a second heavy chain variable region (V_H-2) , a second light chain variable region (V_L- ₂) and an Fc fragment. In some embodiments, the first antibody moiety is fused to one or both of the heavy chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to one or both of the light chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to N-terminus of the one or both of the heavy chains or light chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to C-terminus of the one or both of the heavy chains or light chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to the full-length antibody via a first linker (such as any of the linkers described herein) . In some embodiments, the first antibody moiety is fused to the full-length antibody without a linker. In some embodiments, the V_H-1 is fused with the V_L-1 via a second linker (such as any of the linkers described herein) .

In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the first antibody moiety is a full-length antibody comprising a first heavy chain variable region (V_H-1) , a first light chain variable region (V_L-1) and an Fc fragment, and wherein the second antibody moiety comprises single chain Fv fragment (scFv) comprising a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) . In some embodiments, the second antibody moiety is fused to one or both of the heavy chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to one or both of the light chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to N-terminus of the one or both of the heavy chains or light chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to C-terminus of the one or both of the heavy chains or light chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to the full-length antibody via a first linker (such as any of the linkers described herein) . In some embodiments, the second antibody moiety is fused to the full-length antibody without a linker. In some embodiments, the V_H-2 is fused with the V_L-2 via a second linker (such as any of the linkers described herein) , to enable correct scFv assembling. In some embodiments, the V_H-2 is fused with the V_L-2 without a linker.

In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the first antibody moiety is a full-length antibody comprising a first heavy chain variable region (V_H-1) , a first light chain variable region (V_L-1) and an Fc fragment, and wherein the second antibody moiety comprises single chain Fv fragment (scFv) comprising a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) . In some embodiments, the second antibody moiety is fused to only one of the heavy chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to the full-length antibody via a first linker (such as any of the linkers described herein) . In some embodiments, the second antibody moiety is fused to the full-length antibody without a linker. In some embodiments, the V_H-2 is fused with the V_L-2 via a second linker (such as any of the linkers described herein) , to enable correct scFv assembling. In some embodiments, the V_H-2 is fused with the V_L-2 without a linker.

In some embodiments, there is provided a multispecific construct specifically recognizing Sclerostin and RANKL, comprising a first antibody moiety and a second antibody, wherein the first antibody moiety comprises a first heavy chain variable region (V_H-1) and a first light chain variable region (V_L-1) , and wherein the second antibody moiety comprises a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) , wherein the construct comprises: a) a first polypeptide comprising a first light chain comprising, from N- terminus to C-terminus, i) the V_L-1, ii) a first light chain constant domain ( “first CL domain” ) ; b) a second polypeptide comprising a first heavy chain, from N-terminus to C-terminus, i) the V_H-1, ii) a first heavy chain constant domain ( “first CH1 domain” ) , and iii) a first Fc domain; or i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a second Fc domain; and iv) a scFv fragment comprising the V_H and the V_L; c) a third polypeptide comprising a second heavy chain comprising, from N-terminus to C-terminus, i) the V_H-2, ii) a second heavy chain constant domain ( “second CH1 domain” ) , and iii) a second Fc domain; and d) a fourth polypeptide comprising a second light chain, from N-terminus to C-terminus, i) the V_L-2, ii) a second light chain constant domain ( “the second CL domain” ) , wherein the first and the second Fc domains form a Fc fragment. In some embodiments, the first antibody moiety specifically recognizes Sclerostin, and the second antibody moiety specifically recognizes RANKL. In some embodiments, the first antibody moiety specifically recognizes RANKL, and the second antibody moiety specifically recognizes Sclerostin.

In some embodiments, one of the first and the second Fc domains comprises a T366W mutation, and optionally a S354C mutation, and wherein the other Fc domain comprises a T366S mutation, a L368A mutation, a Y407V mutation, and optionally a Y349C mutation, wherein numbering is according to the EU index.

In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the first antibody moiety is an anti-Sclerostin antibody comprising two Fabs and one Fc fragment, wherein the two Fabs each comprises a first heavy chain variable regions (V_H-1) and a first light chain variable region (V_L-1) , wherein the second Fab fragment is fused to N-terminus of V_H-1 of first Fab or C-terminus of the Fc region that connected to the first Fab, and wherein the second antibody moiety comprises an anti-RANKL half antibody comprising a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) . In some embodiments, the V_H-1 comprises an amino acid sequence of SEQ ID NO: 27, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity; and the V_L-1 comprises an amino acid sequence of SEQ ID NO: 28 or 29, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity. In some embodiments, the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12. In some embodiments, the V_H-2 comprises an amino acid sequence of SEQ ID NO: 13, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity; and the V_L-2 comprises an amino acid sequence of SEQ ID NO: 14, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity.

In some embodiments, there is provided a multispecific (e.g., bispecific) anti-Sclerostin construct comprising a) a first antibody moiety that specifically recognizes Sclerostin comprising a first heavy chain variable region (V_H-1) and a first light chain variable region (V_L-1) , wherein the V_H-1 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3, and the V_L-1 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 6, and b) a second antibody moiety that specifically recognizes RANKL comprising a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) , wherein the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12. In some embodiments, the V_H- ₁ comprises an amino acid sequence of SEQ ID NO: 27, and the V_L-1 comprises an amino acid sequence of SEQ ID NO: 28. In some embodiments, the first antibody moiety is a full-length antibody comprising two heavy chains and two light chains, and the second antibody moiety is a scFv comprising the V_H-2 and V_L-2. In some embodiments, the V_H-2 is fused to the N-terminus of the V_L-2. In some embodiments, the V_H-2 is fused to the C-terminus of the V_L-2 optionally with a single alanine amino acid appended to the C-terminus of V_H-2. In some embodiments, the V_H-2 and the V_L-2 are fused via a linker (e.g., a GS linker, e.g., (GGGGS) ₄) . In some embodiments, the second antibody moiety is fused to N-terminus of one or two heavy chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to C-terminus of one or two heavy chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to N-terminus of one or two light chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to C-terminus of one or two light chains of the full-length antibody. In some embodiments, the second antibody moiety is a full-length antibody comprising two heavy chains and two light chains, and the first antibody moiety is a scFv comprising the V_H- ₁ and the V_L-1. In some embodiments, the V_H-1 is fused to the N-terminus of the V_L-1. In some embodiments, the V_H-1 is fused to the C-terminus of the V_L-1 optionally with a single alanine amino acid appended to the C-terminus of V_H-1. In some embodiments, the V_H-1 and the V_L-1 are fused via a linker (e.g., a GS linker, e.g., (GGGGS) ₄) . In some embodiments, the first antibody moiety is fused to N-terminus of one or two heavy chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to C-terminus of one or two heavy chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to N-terminus of one or two light chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to C-terminus of one or two light chains of the full-length antibody. In some embodiments, the first antibody moiety and the second antibody moiety are fused via a linker (e.g., a GS linker, e.g., (GGGGS) ₃) . In some embodiments, the first antibody moiety and the second antibody moiety are fused without a linker.

In some embodiments, there is provided a multispecific (e.g., bispecific) anti-Sclerostin construct comprising a) a first antibody moiety that specifically recognizes Sclerostin comprising a first heavy chain variable region (V_H-1) and a first light chain variable region (V_L-1) , wherein the V_H-1 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3, and the V_L-1 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 6, and b) a second antibody moiety that specifically recognizes RANKL comprising a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) , wherein the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12. In some embodiments, the V_H- ₁ comprises an amino acid sequence of SEQ ID NO: 27, and the V_L-1 comprises an amino acid sequence of SEQ ID NO: 29. In some embodiments, the first antibody moiety is a full-length antibody comprising two heavy chains and two light chains, and the second antibody moiety is a scFv comprising the V_H-2 and V_L-2. In some embodiments, the V_H-2 is fused to the N-terminus of the V_L-2. In some embodiments, the V_H-2 is fused to the C-terminus of the V_L-2 optionally with a single alanine amino acid appended to the C-terminus of V_H-2. In some embodiments, the V_H-2 and the V_L-2 are fused via a linker (e.g., a GS linker, e.g., (GGGGS) ₄) . In some embodiments, the second antibody moiety is fused to N-terminus of one or two heavy chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to C-terminus of one or two heavy chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to N-terminus of one or two light chains of the full-length antibody. In some embodiments, the second antibody moiety is fused to C-terminus of one or two light chains of the full-length antibody. In some embodiments, the second antibody moiety is a full-length antibody comprising two heavy chains and two light chains, and the first antibody moiety is a scFv comprising the V_H- ₁ and the V_L-1. In some embodiments, the V_H-1 is fused to the N-terminus of the V_L-1. In some embodiments, the V_H-1 is fused to the C-terminus of the V_L-1 optionally with a single alanine amino acid appended to the C-terminus of V_H-1. In some embodiments, the V_H-1 and the V_L-1 are fused via a linker (e.g., a GS linker, e.g., (GGGGS) ₄) . In some embodiments, the first antibody moiety is fused to N-terminus of one or two heavy chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to C-terminus of one or two heavy chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to N-terminus of one or two light chains of the full-length antibody. In some embodiments, the first antibody moiety is fused to C-terminus of one or two light chains of the full-length antibody. In some embodiments, the first antibody moiety and the second antibody moiety are fused via a linker (e.g., a GS linker, e.g., (GGGGS) ₃) . In some embodiments, the first antibody moiety and the second antibody moiety are fused without a linker.

In some embodiments, there is provided a multispecific (e.g., bispecific) construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the multispecific construct comprises two heavy chains and two light chains, wherein the two light chain comprise the amino acid sequence of SEQ ID NO: 30, the first heavy chain comprises the amino acid sequence of SEQ ID NO: 33, and the second heavy chain comprises the amino acid sequence of SEQ ID NO: 34.

In some embodiments, there is provided a multispecific (e.g., bispecific) construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the multispecific construct comprises two heavy chains and two light chains, wherein the two light chain comprise the amino acid sequence of SEQ ID NO: 30, the first heavy chain comprises the amino acid sequence of SEQ ID NO: 36, and the second heavy chain comprises the amino acid sequence of SEQ ID NO: 37.

In some embodiments, there is provided a multispecific (e.g., bispecific) construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the multispecific construct comprises two heavy chains and two light chains, wherein the two light chain comprise the amino acid sequence of SEQ ID NO: 30, the first heavy chain comprises the amino acid sequence of SEQ ID NO: 42, and the second heavy chain comprises the amino acid sequence of SEQ ID NO: 43.

In some embodiments, there is provided a multispecific (e.g., bispecific) construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the multispecific construct comprises two heavy chains and two light chains, wherein the two light chain comprise the amino acid sequence of SEQ ID NO: 30, the first heavy chain comprises the amino acid sequence of SEQ ID NO: 46, and the second heavy chain comprises the amino acid sequence of SEQ ID NO: 47.

In some embodiments, the anti-RANKL antibody moiety and the anti-Sclerostin antibody moiety are fused with each other via a linker such as any of the linkers described herein with any operable form that allows the proper function of the binding moieties.

In some embodiments, there is provided a multispecific construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the first antibody moiety is an anti-Sclerostin full-length antibody comprising two heavy chains and two light chains, wherein the two heavy chains each comprises a first heavy chain variable region (V_H-1) , wherein the two light chains each comprises a first light chain variable region (V_L-1) , and wherein the second antibody moiety comprises an anti-RANKL single chain Fv fragment (scFv) comprising a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) , wherein the second antibody moiety is fused to C-terminus of one of the two heavy chains of the anti-Sclerostin full-length antibody. In some embodiments, the V_H-1 comprises an amino acid sequence of SEQ ID NO: 27, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity; and the V_L-1 comprises an amino acid sequence of SEQ ID NO: 28 or 29, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity. In some embodiments, the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12. In some embodiments, the V_H-2 comprises an amino acid sequence of SEQ ID NO: 13, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity; and the V_L-2 comprises an amino acid sequence of SEQ ID NO: 14, or a variant comprising an amino acid sequence having at least about 80% (such as at least about any one of 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) sequence identity.

In some embodiments, there is provided a multispecific (e.g., bispecific) construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the multispecific construct comprises two heavy chains and three light chains, wherein the first and second light chain comprise the amino acid sequence of SEQ ID NO: 31, the third light chain comprises the amino acid sequence of SEQ ID NO: 32, the first heavy chain comprises the amino acid sequence of SEQ ID NO: 38, and the second heavy chain comprises the amino acid sequence of SEQ ID NO: 39.

In some embodiments, there is provided a multispecific (e.g., bispecific) construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the multispecific construct comprises two heavy chains and three light chains, wherein the first and second light chain comprise the amino acid sequence of SEQ ID NO: 31, the third light chain comprises the amino acid sequence of SEQ ID NO: 32, the first heavy chain comprises the amino acid sequence of SEQ ID NO: 38, and the second heavy chain comprises the amino acid sequence of SEQ ID NO: 41.

In some embodiments, there is provided a multispecific (e.g., bispecific) construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the multispecific construct comprises two heavy chains and three light chains, wherein the first and second light chain comprise the amino acid sequence of SEQ ID NO: 31, the third light chain comprises the amino acid sequence of SEQ ID NO: 32, the first heavy chain comprises the amino acid sequence of SEQ ID NO: 40, and the second heavy chain comprises the amino acid sequence of SEQ ID NO: 41.

In some embodiments, there is provided a multispecific (e.g., bispecific) construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the multispecific construct comprises two heavy chains and three light chains, wherein the first and second light chain comprise the amino acid sequence of SEQ ID NO: 31, the third light chain comprises the amino acid sequence of SEQ ID NO: 32, the first heavy chain comprises the amino acid sequence of SEQ ID NO: 44, and the second heavy chain comprises the amino acid sequence of SEQ ID NO: 45.

In some embodiments, the construct comprises or is an antibody or antigen-binding fragment thereof selected from the group consisting of a full-length antibody, a bispecific antibody, a single-chain Fv (scFv) fragment, a Fab fragment, a Fab’ fragment, a F (ab’) 2, an Fv fragment, a disulfide stabilized Fv fragment (dsFv) , a dsscFv, a (dsFv) ₂, a V_HH, a Fv-Fc fusion, a scFv-Fc fusion, a scFv-Fv fusion, a diabody, a tribody, and a tetrabody.

In some embodiments, the anti-Sclerostin antibody and/or the anti-RANKL antibody moiety is a full-length antibody.

In some embodiments, the anti-Sclerostin antibody and/or the anti-RANKL antibody moiety is a scFv or dsscFv.

In some embodiments, the anti-Sclerostin antibody moiety and/or the anti-RANKL antibody described above comprises an Fc fragment of an immunoglobulin selected from the group consisting of IgG, IgA, IgD, IgE, IgM, and combinations and hybrids thereof. In some embodiments, the anti-Sclerostin antibody moiety or the full-length antibody described above comprises an Fc fragment of an immunoglobulin selected from the group consisting of IgG1, IgG2, IgG3, IgG4, and combinations and hybrids thereof. In some embodiments, the Fc fragment has a reduced effector function as compared to the corresponding wildtype Fc fragment. In some embodiments, the Fc fragment has an enhanced effector function as compared to the corresponding wildtype Fc fragment.

In some embodiments, the antibody moiety comprises a humanized antibody of any of the antibody moiety described herein.

In some embodiments, the bispecific construct comprises or is a fusion protein.

In some embodiments, the bispecific construct comprises or is a multispecific bispecific construct (such as a bispecific antibody) .

In some embodiments, the Sclerostin is a human Sclerostin and/or the RANKL is a human RANKL.

a) Antibody affinity

Binding specificity of the antibody moieties can be determined experimentally by methods known in the art. Such methods comprise, but are not limited to Western blots, ELISA-, RIA-, ECL-, IRMA-, EIA-, BLI-, BIACORE^TM -tests and peptide scans.

In some embodiments, the K_D of the binding between the antibody moiety and Sclerostin and/or RANKL is about 10^-7 M to about 10^-12 M, about 10^-7 M to about 10^-8 M, about 10^-8 M to about 10^-9 M, about 10^-9 M to about 10^-10 M, about 10^-10 M to about 10^-11 M, about 10^-11 M to about 10^-12 M, about 10^-7 M to about 10^-12 M, about 10^-8 M to about 10^-12 M, about 10^-9 M to about 10^-12 M, about 10^-10 M to about 10^-12 M, about 10^-7 M to about 10^-11 M, about 10^-8 M to about 10^- ¹¹ M, about 10^-9 M to about 10^-11 M, about 10^-7 M to about 10^-10 M, about 10^-8 M to about 10^-10 M, or about 10^-7 M to about 10^-9 M. In some embodiments, the K_D of the binding between the antibody moiety and Sclerostin is stronger than about any one of 10^-7 M, 10^-8 M, 10^-9 M, 10^-10 M, 10^-11 M, or 10^-12 M. In some embodiments, the Sclerostin is a human Sclerostin and/or the RANKL is a human RANKL. In some embodiments, Sclerostin is cynomolgus Sclerostin.

In some embodiments, the K_on of the binding between the antibody moiety and Sclerostin and/or RANKL is about 10³ M^-1s^-1 to about 10⁸ M^-1s^-1, about 10³ M^-1s^-1 to about 10⁴ M^-1s^-1, about 10⁴ M^-1s^-1 to about 10⁵ M^-1s^-1, about 10⁵ M^-1s^-1 to about 10⁶ M^-1s^-1, about 10⁶ M^-1s^-1 to about 10⁷ M^-1s^-1, or about 10⁷ M^-1s^-1 to about 10⁸ M^-1s^-1. In some embodiments, the K_on of the binding between the antibody moiety and Sclerostin is about 10³ M^-1s^-1 to about 10⁵ M^-1s^-1, about 10⁴ M^- ¹s^-1 to about 10⁶ M^-1s^-1, about 10⁵ M^-1s^-1 to about 10⁷ M^-1s^-1, about 10⁶ M^-1s^-1 to about 10⁸ M^-1s^-1, about 10⁴ M^-1s^-1 to about 10⁷ M^-1s^-1, or about 10⁵ M^-1s^-1 to about 10⁸ M^-1s^-1. In some embodiments, the K_on of the binding between the antibody moiety and Sclerostin is no more than about any one of 10³ M^-1s^-1, 10⁴ M^-1s^-1, 10⁵ M^-1s^-1, 10⁶ M^-1s^-1, 10⁷ M^-1s^-1 or 10⁸ M^-1s^-1. In some embodiments, the Sclerostin is a human Sclerostin and/or the RANKL is a human RANKL. In some embodiments, Sclerostin is cynomolgus Sclerostin.

In some embodiments, the K_off of the binding between the antibody moiety and Sclerostin and/or RANKL is about 1 s^-1 to about 10^-6 s^-1, about 1 s^-1 to about 10^-2 s^-1, about 10^-2 s^-1 to about 10^-3 s^-1, about 10^-3 s^-1 to about 10^-4 s^-1, about 10^-4 s^-1 to about 10^-5 s^-1, about 10^-5 s^-1 to about 10^-6 s^- ¹, about 1 s^-1 to about 10^-5 s^-1, about 10^-2 s^-1 to about 10^-6 s^-1, about 10^-3 s^-1 to about 10^-6 s^-1, about 10^-4 s^-1 to about 10^-6 s^-1, about 10^-2 s^-1 to about 10^-5 s^-1, or about 10^-3 s^-1 to about 10^-5 s^-1. In some embodiments, the K_off of the binding between the antibody moiety and Sclerostin and/or RANKL is at least about any one of 1 s^-1, 10^-2 s^-1, 10^-3 s^-1, 10^-4 s^-1, 10^-5 s^-1 or 10^-6 s^-1. In some embodiments, Sclerostin and/or the RANKL is a human RANKL is human Sclerostin. In some embodiments, Sclerostin is cynomolgus Sclerostin.

In some embodiments, the binding affinity of the anti-Sclerostin antibody moiety and/or the anti-RANKL antibody moiety or bispecific construct are higher (for example, has a smaller K_D value) than an existing anti-Sclerostin antibody (e.g., Romosozumab) .

b) Chimeric or humanized antibodies

In some embodiments, the bispecific construct (e.g., the anti-Sclerostin antibody moiety) is a chimeric antibody. Certain chimeric antibodies are described. In some embodiments, a chimeric antibody comprises a non-human variable region (e.g., a variable region derived from mouse) and a human constant region. In some embodiments, a chimeric antibody is a “class switched” antibody in which the class or subclass has been changed from that of the parent antibody. Chimeric antibodies include antigen-binding fragments thereof.

In some embodiments, the bispecific construct (e.g., the anti-Sclerostin antibody moiety) is a humanized antibody. Typically, a non-human antibody is humanized to reduce immunogenicity to humans, while retaining the specificity and affinity of the parental non-human antibody. Generally, a humanized antibody comprises one or more variable domains in which HVRs, e.g., CDRs, (or portions thereof) are derived from a non-human antibody, and FRs (or portions thereof) are derived from human antibody sequences. A humanized antibody optionally will also comprise at least a portion of a human constant region. In some embodiments, some FR residues in a humanized antibody are substituted with corresponding residues from a non-human antibody (e.g., the antibody from which the HVR residues are derived) , e.g., to restore or improve antibody specificity or affinity.

Human framework regions that may be used for humanization include but are not limited to:framework regions selected using the “best-fit” method; Framework regions derived from the consensus sequence of human antibodies of a particular subgroup of light or heavy chain variable regions; human mature (somatically mutated) framework regions or human germline framework regions; and framework regions derived from screening FR libraries.

It is understood that the humanization of mouse derived antibodies is a common and routinely used art. It is therefore understood that a humanized format of any and all of the anti-Sclerostin antibodies disclosed in Sequence Table can be used in a preclinical or clinical setting. In cases where a humanized format of any of the referenced anti-Sclerostin antibodies or their antigen-binding regions thereof is used in such a preclinical or clinical setting, the then humanized format is expected to bear the same or similar biological activities and profiles as the original non-humanized format.

c) Human antibodies

In some embodiments, the bispecific construct (e.g., the anti-Sclerostin antibody moiety) is a human antibody (known as human domain antibody, or human dAb) . Human antibodies can be produced using various techniques known in the art.

Human antibodies (e.g., human dAbs) may be prepared by administering an immunogen to a transgenic animal that has been modified to produce intact human antibodies or intact antibodies with human variable regions in response to antigenic challenge. Such animals typically contain all or a portion of the human immunoglobulin loci, which replace the endogenous immunoglobulin loci, or which are present extrachromosomally or integrated randomly into the animal’s chromosomes. In such transgenic mice, the endogenous immunoglobulin loci have generally been inactivated. Human variable regions from intact antibodies generated by such animals may be further modified, e.g., by combining with a different human constant region.

Human antibodies (e.g., human dAbs) may also be generated by isolating Fv clone variable domain sequences selected from human-derived phage display libraries. Such variable domain sequences may then be combined with a desired human constant domain. Techniques for selecting human antibodies from antibody libraries are described below.

d) Library-derived antibodies

The anti-Sclerostin antibody moieties described herein may be isolated by screening combinatorial libraries for antibodies with the desired activity or activities. For example, a variety of methods are known in the art for generating phage display libraries and screening such libraries for antibodies possessing the desired binding characteristics.

In certain phage display methods, repertoires of V_H and V_L genes are separately cloned by polymerase chain reaction (PCR) and recombined randomly in phage libraries, which can then be screened for antigen-binding phage. Phage typically displays antibody fragments, either as scFv fragments or as Fab fragments. Libraries from immunized sources provide high-affinity antibodies to the immunogen without the requirement of constructing hybridomas. Alternatively, the naive repertoire can be cloned (e.g., from human) to provide a single source of antibodies to a wide range of non-self and also self-antigens without any immunization. Finally, naive libraries can also be made synthetically by cloning unrearranged V-gene segments from stem cells, and using PCR primers containing random sequence to encode the highly variable CDR3 regions and to accomplish rearrangement in vitro.

Antibodies or antibody fragments isolated from human antibody libraries are considered human antibodies or human antibody fragments herein.

e) Substitution, insertion, deletion and variants

In some embodiments, antibody variants having one or more amino acid substitutions are provided. Sites of interest for substitutional mutagenesis include the HVRs (or CDRs) and FRs. Conservative substitutions are shown in Table 2 under the heading of “Preferred substitutions. ” More substantial changes are provided in Table 2 under the heading of “exemplary substitutions, ” and as further described below in reference to amino acid side chain classes. Amino acid substitutions may be introduced into an antibody of interest and the products screened for a desired activity, e.g., retained/improved antigen binding, decreased immunogenicity, or improved ADCC or CDC.

Table 2. Amino acid substitutions

Amino acids may be grouped according to common side-chain properties: (1) hydrophobic: Norleucine, Met, Ala, Val, Leu, Ile; (2) neutral hydrophilic: Cys, Ser, Thr, Asn, Gln; (3) acidic: Asp, Glu; (4) basic: His, Lys, Arg; (5) residues that influence chain orientation: Gly, Pro; and (6) aromatic: Trp, Tyr, Phe.

Non-conservative substitutions will entail exchanging a member of one of these classes for another class.

One type of substitutional variant involves substituting one or more hypervariable region residues of a parent antibody (e.g., a humanized or human antibody) . Generally, the resulting variant (s) selected for further study will have modifications (e.g., improvements) in certain biological properties (e.g., increased affinity, reduced immunogenicity) relative to the parent antibody and/or will have substantially retained certain biological properties of the parent antibody. An exemplary substitutional variant is an affinity matured antibody, which may be conveniently generated, e.g., using phage display-based affinity maturation techniques such as those described herein. Briefly, one or more HVR residues are mutated and the variant antibodies displayed on phage and screened for a particular biological activity (e.g. binding affinity) .

Alterations (e.g., substitutions) may be made in HVRs, e.g., to improve antibody affinity. Such alterations may be made in HVR “hotspots, ” i.e., residues encoded by codons that undergo mutation at high frequency during the somatic maturation process, and/or SDRs (a-CDRs) , with the resulting variant V_H or V_L being tested for binding affinity. Affinity maturation can be achieved by constructing and reselecting from secondary libraries. In some embodiments of affinity maturation, diversity is introduced into the variable genes chosen for maturation by any of a variety of methods (e.g., error-prone PCR, chain shuffling, or oligonucleotide-directed mutagenesis) . A secondary library is then created. The library is then screened to identify any antibody variants with the desired affinity. Another method to introduce diversity involves HVR-directed approaches, in which several HVR residues (e.g., 4-6 residues at a time) are randomized. HVR residues involved in antigen binding may be specifically identified, e.g., using alanine scanning mutagenesis or modeling. CDR-H3 and CDR-L3 in particular are often targeted.

In some embodiments, substitutions, insertions, or deletions may occur within one or more HVRs so long as such alterations do not substantially reduce the ability of the antibody to bind antigen. For example, conservative alterations (e.g., conservative substitutions as provided herein) that do not substantially reduce binding affinity may be made in HVRs. Such alterations may be outside of HVR “hotspots” or CDRs.

A useful method for identification of residues or regions of an antibody that may be targeted for mutagenesis is called “alanine scanning mutagenesis” . In this method, a residue or group of target residues (e.g., charged residues such as Arg, Asp, His, Lys, and Glu) are identified and replaced by a neutral or negatively charged amino acid (e.g., alanine or polyalanine) to determine whether the interaction of the antibody with antigen is affected. Further substitutions may be introduced at the amino acid locations demonstrating functional sensitivity to the initial substitutions. Alternatively, or additionally, a crystal structure of an antigen-antibody complex to identify contact points between the antibody and antigen. Such contact residues and neighboring residues may be targeted or eliminated as candidates for substitution. Variants may be screened to determine whether they contain the desired properties.

Amino acid sequence insertions include amino-and/or carboxyl-terminal fusions ranging in length from one residue to polypeptides containing a hundred or more residues, as well as intrasequence insertions of single or multiple amino acid residues. Examples of terminal insertions include an antibody with an N-terminal methionyl residue. Other insertional variants of the antibody molecule include the fusion to the N-or C-terminus of the antibody to an enzyme (e.g., for ADEPT) or a polypeptide which increases the serum half-life of the antibody.

f) Glycosylation variants

In some embodiments, the bispecific construct (e.g., the anti-Sclerostin antibody moiety) is altered to increase or decrease the extent to which the construct is glycosylated. Addition or deletion of glycosylation sites to an antibody may be conveniently accomplished by altering the amino acid sequence such that one or more glycosylation sites is created or removed.

Where the antibody moiety comprises an Fc region, the carbohydrate attached thereto may be altered. Native antibodies produced by mammalian cells typically comprise a branched, biantennary oligosaccharide that is generally attached by an N-linkage to Asn297 of the C_H2 domain of the Fc region. The oligosaccharide may include various carbohydrates, e.g., mannose, N-acetyl glucosamine (GlcNAc) , galactose, and sialic acid, as well as a fucose attached to a GlcNAc in the “stem” of the biantennary oligosaccharide structure. In some embodiments, modifications of the oligosaccharide in the antibody moiety may be made in order to create antibody variants with certain improved properties.

In some embodiments, the bispecific construct (e.g., the anti-Sclerostin antibody moiety) has a carbohydrate structure that lacks fucose attached (directly or indirectly) to an Fc region. For example, the amount of fucose in such antibody may be from 1%to 80%, from 1%to 65%, from 5%to 65%or from 20%to 40%. The amount of fucose is determined by calculating the average amount of fucose within the sugar chain at Asn297, relative to the sum of all glycostructures attached to Asn 297 (e.g., complex, hybrid and high mannose structures) as measured by MALDI-TOF mass spectrometry, as described in WO 2008/077546, for example. Asn297 refers to the asparagine residue located at about position 297 in the Fc region (EU numbering of Fc region residues) ; however, Asn297 may also be located about ± 3 amino acids upstream or downstream of position 297, i.e., between positions 294 and 300, due to minor sequence variations in antibodies. Such fucosylation variants may have improved ADCC function. See, e.g., US Patent Publication Nos. US 2003/0157108 (Presta, L. ) ; US 2004/0093621 (Kyowa Hakko Kogyo Co., Ltd) . Examples of publications related to “defucosylated” or “fucose-deficient” antibody variants include: US 2003/0157108; WO 2000/61739; WO 2001/29246; US 2003/0115614; US 2002/0164328; US 2004/0093621; US 2004/0132140; US 2004/0110704; US 2004/0110282; US 2004/0109865; WO 2003/085119; WO 2003/084570; WO 2005/035586; WO 2005/035778; WO2005/053742; WO2002/031140. Examples of cell lines capable of producing defucosylated antibodies include Lec13 CHO cells deficient in protein fucosylation (US Patent Application No. US 2003/0157108 A1, Presta, L; and WO 2004/056312 A1, Adams et al., especially at Example 11) , and knockout cell lines, such as alpha-1, 6-fucosyltransferase gene, FUT8, knockout CHO cells (WO2003/085107) .

In some embodiments, the bispecific construct (e.g., the anti-Sclerostin antibody moiety) has bisected oligosaccharides, e.g., in which a biantennary oligosaccharide attached to the Fc region of the antibody is bisected by GlcNAc. Such antibody variants may have reduced fucosylation and/or improved ADCC function. Examples of such antibody variants are described, e.g., in WO 2003/011878 (Jean-Mairet et al. ) ; US Patent No. 6, 602, 684 (Umana et al. ) ; and US 2005/0123546 (Umana et al. ) . Antibody variants with at least one galactose residue in the oligosaccharide attached to the Fc region are also provided. Such antibody variants may have improved CDC function. Such antibody variants are described, e.g., in WO 1997/30087 (Patel et al. ) ; WO 1998/58964 (Raju, S. ) ; and WO 1999/22764 (Raju, S. ) .

g) Fc region variants and light chain constant region variants

In some embodiments, the bispecific construct (e.g., the anti-Sclerostin antibody moiety) comprises an Fc fragment.

The term “Fc region, ” “Fc domain, ” “Fc fragment” or “Fc” refers to a C-terminal non-antigen binding region of an immunoglobulin heavy chain that contains at least a portion of the constant region. The term includes native Fc regions and variant Fc regions. In some embodiments, a human IgG heavy chain Fc region extends from Cys226 to the carboxyl-terminus of the heavy chain. However, the C-terminal lysine (Lys447) of the Fc region may or may not be present, without affecting the structure or stability of the Fc region. Unless otherwise specified herein, numbering of amino acid residues in the IgG or Fc region is according to the EU numbering system for antibodies, also called the EU index, as described in Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD, 1991.

In some embodiments, the Fc fragment is from an immunoglobulin selected from the group consisting of IgG, IgA, IgD, IgE, IgM, and combinations and hybrids thereof. In some embodiments, the Fc fragment is from an immunoglobulin selected from the group consisting of IgG1, IgG2, IgG3, IgG4, and combinations and hybrids thereof.

In some embodiments, the Fc fragment has a reduced effector function as compared to corresponding wildtype Fc fragment (such as at least about 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, or 95%reduced effector function as measured by the level of antibody-dependent cellular cytotoxicity (ADCC) ) .

In some embodiments, the Fc fragment is an IgG1 Fc fragment. In some embodiments, the IgG1 Fc fragment comprises a L234A mutation and/or a L235A mutation. In some embodiments, the Fc fragment is an IgG2 or IgG4 Fc fragment. In some embodiments, the Fc fragment is an IgG4 Fc fragment comprising a S228P, F234A, and/or a L235A mutation. In some embodiments, the Fc fragment comprises a N297A mutation. In some embodiments, the Fc fragment comprises a N297G mutation.

In some embodiments, one or more amino acid modifications may be introduced into the Fc region of the antibody moiety, thereby generating an Fc region variant. The Fc region variant may comprise a human Fc region sequence (e.g., a human IgG1, IgG2, IgG3 or IgG4 Fc region) comprising an amino acid modification (e.g. a substitution) at one or more amino acid positions. In some embodiments, the Fc fragment is derived from a rat Fc region sequence (e.g., a rat IgG2 Fc) or a mouse Fc region sequence (e.g., a mouse IgG1 Fc) .

In some embodiments, the Fc fragment comprises a human IgG2 Fc region.

In some embodiments, the Fc fragment comprises a human IgG4 Fc region. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising one or more (such as two, three, or four) substitutions selected from the group consisting of S228P, T366W, and optional H435R, and optional Y436F. The numberings of the modifications described herein are according to the EU index unless otherwise noted. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising S228P, T366W, and optional H435R, and optional Y436F. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising one or more (such as two, three, four, five or six) substitutions selected from the group consisting of F126C, L128C, C131S, F170C, P161C, V173C, S228P, T366S, L368A, and Y407V, and optional H435R, and optional Y436F. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising a) C131S, S228P, T366S, L368A, and Y407V, and b) one of the substitutions selected from the group consisting of F126C, L128C, F170C, P161C, and V173C, and c) optional H435R, and optional Y436F. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising one or more (such as two, three, four, five or six) substitutions selected from the group consisting of F126C, C131S, S228P, T366S, L368A, and Y407V, and optional H435R, and optional Y436F. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising F126C, C131S, S228P, T366S, L368A, and Y407V, and optional H435R, and optional Y436F. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising L128C, C131S, S228P, T366S, L368A, and Y407V, and optional H435R, and optional Y436F. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising C131S, F170C, S228P, T366S, L368A, and Y407V, and optional H435R, and optional Y436F. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising C131S, V173C, S228P, T366S, L368A, and Y407V, and optional H435R, and optional Y436F. In some embodiments, the Fc fragment comprises a modified human IgG4 heavy chain Fc region comprising C131S, P171C, S228P, T366S, L368A, and Y407V, and optional H435R, and optional Y436F.

In some embodiments, the bispecific construct comprises a Fc fragment comprising a) a first modified human IgG4 heavy chain Fc region comprising S228P, T366W, and b) a second modified human IgG4 heavy chain Fc region comprising a) C131S, S228P, T366S, L368A, and Y407V, and optional H435R, and optional Y436F, and b) one of the substitutions selected from the group consisting of F126C, L128C, F170C, P161C, and V173C.

In some embodiments, the bispecific construct comprises a Fc fragment comprising a) a first modified human IgG4 heavy chain Fc region comprising S228P, T366W, and b) a second modified human IgG4 heavy chain Fc region comprising F126C, C131S, S228P, T366S, L368A, Y407V, H435R, and Y436F.

In some embodiments, the bispecific construct comprises a Fc fragment comprising a) a first modified human IgG4 heavy chain Fc region comprising S228P, T366W, and b) a second modified human IgG4 heavy chain Fc region comprising L128C, C131S, S228P, T366S, L368A, Y407V, H435R, and Y436F.

In some embodiments, the bispecific construct comprises a Fc fragment comprising a) a first modified human IgG4 heavy chain Fc region comprising S228P, T366W, and b) a second modified human IgG4 heavy chain Fc region comprising C131S, F170C, S228P, T366S, L368A, Y407V, H435R, and Y436F.

In some embodiments, the bispecific construct comprises a Fc fragment comprising a) a first modified human IgG4 heavy chain Fc region comprising S228P, T366W, and b) a second modified human IgG4 heavy chain Fc region comprising C131S, V173C, S228P, T366S, L368A, Y407V, H435R, and Y436F.

In some embodiments, the bispecific construct comprises a Fc fragment comprising a) a first modified human IgG4 heavy chain Fc region comprising S228P, T366W, and b) a second modified human IgG4 heavy chain Fc region comprising C131S, P171C, S228P, T366S, L368A, Y407V, H435R, and Y436F.

In some embodiments, the bispecific construct comprises a human Ig kappa light chain constant region. In some embodiments, the bispecific construct comprises a modified human Ig kappa light chain constant region comprising F118C, S121C, Q160C, S162C, S176C, and/or C214S. In some embodiments, the bispecific construct comprises a modified human Ig kappa light chain constant region comprising S121C and C214S. In some embodiments, the bispecific construct comprises a modified human Ig kappa light chain constant region comprising F118C and C214S. In some embodiments, the bispecific construct comprises a modified human Ig kappa light chain constant region comprising S176C and C214S. In some embodiments, the bispecific construct comprises a modified human Ig kappa light chain constant region comprising Q160C and C214S. In some embodiments, the bispecific construct comprises a modified human Ig kappa light chain constant region comprising S162C and C214S.

In some embodiments, the Fc fragment possesses some but not all effector functions, which make it a desirable candidate for applications in which the half-life of the antibody moiety in vivo is important yet certain effector functions (such as complement and ADCC) are unnecessary or deleterious. In vitro and/or in vivo cytotoxicity assays can be conducted to confirm the reduction/depletion of CDC and/or ADCC activities. For example, Fc receptor (FcR) binding assays can be conducted to ensure that the antibody lacks FcγR binding (hence likely lacking ADCC activity) , but retains FcRn binding ability. The primary cells for mediating ADCC, NK cells, express FcγRIII only, whereas monocytes express FcγRI, FcγRII and FcγRIII. Non-limiting examples of in vitro assays to assess ADCC activity of a molecule of interest is described in U.S. Patent No. 5,500,362 . Alternatively, non-radioactive assays methods may be employed (see, for example, ACTI^TM non-radioactive cytotoxicity assay for flow cytometry (CellTechnology, Inc. Mountain View, CA; and CytoToxnon-radioactive cytotoxicity assay (Promega, Madison, WI) . Useful effector cells for such assays include peripheral blood mononuclear cells (PBMC) and Natural Killer (NK) cells. Alternatively, or additionally, ADCC activity of the molecule of interest may be assessed in vivo. C1q binding assays may also be carried out to confirm that the antibody is unable to bind C1q and hence lacks CDC activity. See, e.g., C1q and C3c binding ELISA in WO 2006/029879 and WO 2005/100402. To assess complement activation, a CDC assay may be performed. FcRn binding and in vivo clearance/half-life determinations can also be performed using methods known in the art.

Antibodies with reduced effector function include those with substitution of one or more of Fc region residues 238, 265, 269, 270, 297, 327 and 329 (U.S. Patent No. 6, 737, 056) . Such Fc mutants include Fc mutants with substitutions at two or more of amino acid positions 265, 269, 270, 297 and 327, including the so-called “DANA” Fc mutant with substitution of residues 265 and 297 to alanine (US Patent No. 7, 332, 581) . In some embodiments, the Fc fragment comprises a N297A mutation. In some embodiments, the Fc fragment comprises a N297G mutation.

Certain antibody variants with improved or diminished binding to FcRs are described. (See, e.g., U.S. Patent No. 6, 737, 056; WO 2004/056312. )

In some embodiments, the Fc fragment is an IgG1 Fc fragment. In some embodiments, the IgG1 Fc fragment comprises a L234A mutation and/or a L235A mutation. In some embodiments, the Fc fragment is an IgG2 or IgG4 Fc fragment. In some embodiments, the Fc fragment is an IgG4 Fc fragment comprising a S228P, F234A, and/or a L235A mutation.

In some embodiments, the antibody moiety comprises an Fc region with one or more amino acid substitutions which improve ADCC, e.g., substitutions at positions 298, 333, and/or 334 of the Fc region (EU numbering of residues) .

In some embodiments, alterations are made in the Fc region that result in altered (i.e., either improved or diminished) C1q binding and/or Complement Dependent Cytotoxicity (CDC) , e.g., as described in US Patent No. 6,194,551, WO 99/51642.

In some embodiments, the antibody moiety variant comprising a variant Fc region comprising one or more amino acid substitutions which alters half-life and/or changes binding to the neonatal Fc receptor (FcRn) . Antibodies with increased half-lives and improved binding to the neonatal Fc receptor (FcRn) , which is responsible for the transfer of maternal IgGs to the fetus, are described in US2005/0014934A1 (Hinton et al. ) . Those antibodies comprise an Fc region with one or more substitutions therein which alters binding of the Fc region to FcRn. Such Fc variants include those with substitutions at one or more of Fc region residues at positions 250, 252, 254, 256, 307, 308, 428, 434 (US Patent No. 7,371,826) , including the so-called “LS” Fc mutant comprising M428L and N434S (WO 2009/086320) , and so-called “YTE” Fc mutant comprising M252Y, S254T and T256E (WO 2002/060919) .

See also U.S. Patent No. 5,648,260; U.S. Patent No. 5,624,821; and WO 94/29351 concerning other examples of Fc region variants.

h) Cysteine engineered antibody variants

In some embodiments, it may be desirable to create cysteine engineered antibody moieties, e.g., “thioMAbs, ” in which one or more residues of an antibody are substituted with cysteine residues. In particular embodiments, the substituted residues occur at accessible sites of the antibody. By substituting those residues with cysteine, reactive thiol groups are thereby positioned at accessible sites of the antibody and may be used to conjugate the antibody to other moieties, such as drug moieties or linker-drug moieties, to create an antibody-drug conjugate, as described further herein. In some embodiments, any one or more of the following residues may be substituted with cysteine: A118 (EU numbering) of the heavy chain; and S400 (EU numbering) of the heavy chain Fc region. Cysteine engineered antibody moieties may be generated as described, e.g., in U.S. Patent No. 7,521,541.

i) Antibody derivatives

In some embodiments, the antibody moiety described herein may be further modified to comprise additional nonproteinaceous moieties that are known in the art and readily available. The moieties suitable for derivatization of the antibody include but are not limited to water soluble polymers. Non-limiting examples of water soluble polymers include, but are not limited to, polyethylene glycol (PEG) , copolymers of ethylene glycol/propylene glycol, carboxymethylcellulose, dextran, polyvinyl alcohol, polyvinyl pyrrolidone, poly-1, 3-dioxolane, poly-1, 3, 6-trioxane, ethylene/maleic anhydride copolymer, polyaminoacids (either homopolymers or random copolymers) , and dextran or poly (n-vinyl pyrrolidone) polyethylene glycol, propropylene glycol homopolymers, prolypropylene oxide/ethylene oxide co-polymers, polyoxyethylated polyols (e.g., glycerol) , polyvinyl alcohol, and mixtures thereof. Polyethylene glycol propionaldehyde may have advantages in manufacturing due to its stability in water. The polymer may be of any molecular weight, and may be branched or unbranched. The number of polymers attached to the antibody may vary, and if more than one polymer are attached, they can be the same or different molecules. In general, the number and/or type of polymers used for derivatization can be determined based on considerations including, but not limited to, the particular properties or functions of the antibody to be improved, whether the antibody derivative will be used in diagnosis under defined conditions, etc.

In some embodiments, the antibody moiety may be further modified to comprise one or more biologically active protein, polypeptides or fragments thereof. “Bioactive” or “biologically active” , as used herein interchangeably, means showing biological activity in the body to carry out a specific function. For example, it may mean the combination with a particular biomolecule such as protein, DNA, etc., and then promotion or inhibition of the activity of such biomolecule. In some embodiments, the bioactive protein or fragments thereof include proteins and polypeptides that are administered to patients as the active drug substance for prevention of or treatment of a disease or condition, as well as proteins and polypeptides that are used for diagnostic purposes, such as enzymes used in diagnostic tests or in vitro assays, as well as proteins and polypeptides that are administered to a patient to prevent a disease such as a vaccine.

Bispecific fusion proteins or antibody-drug conjugate

The bispecific constructs in some embodiments is a fusion protein or an antibody-drug conjugate that comprises an anti-Sclerostin antibody moiety (e.g., an anti-Sclerostin scFv) and a second moiety (e.g., an anti-RANKL scFv) .

In some embodiments, the second moiety comprises a half-life extending moiety. In some embodiments, the half-life extending moiety is an albumin binding moiety (e.g., an albumin binding antibody moiety) .

In some embodiments, the second moiety comprises an agent selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , a bisphosphonate, a prostaglandin E (PGE) receptor agonist, VEGF, TGFβ, growth factor (myostatin) and calcitonin.

In some embodiments, the anti-Sclerostin antibody moiety and the second moiety are fused via a linker (such as any of the linkers described in the “Linkers” section) . In some embodiments, the anti-Sclerostin antibody moiety and the second moiety are fused without a linker.

Linkers

In some embodiments, the bispecific constructs described herein comprise one or more linkers between two moieties (e.g., the anti-Sclerostin antibody moiety and the half-life extending moiety, the anti-Sclerostin antibody moiety and the second binding moiety in the multispecific constructs described above) . The length, the degree of flexibility and/or other properties of the linker (s) used in the anti-Sclerostin constructs may have some influence on properties, including but not limited to the affinity, specificity or avidity for one or more particular antigens or epitopes. For example, longer linkers may be selected to ensure that two adjacent domains do not sterically interfere with one another. In some embodiment, a linker (such as peptide linker) comprises flexible residues (such as glycine and serine) so that the adjacent domains are free to move relative to each other. For example, a glycine-serine doublet can be a suitable peptide linker. In some embodiments, the linker is a non-peptide linker. In some embodiments, the linker is a peptide linker. In some embodiments, the linker is a non-cleavable linker. In some embodiments, the linker is a cleavable linker.

Other linker considerations include the effect on physical or pharmacokinetic properties of the resulting compound, such as solubility, lipophilicity, hydrophilicity, hydrophobicity, stability (more or less stable as well as planned degradation) , rigidity, flexibility, immunogenicity, modulation of antibody binding, the ability to be incorporated into a micelle or liposome, and the like.

Peptide linkers

The peptide linker may have a naturally occurring sequence, or a non-naturally occurring sequence. For example, a sequence derived from the hinge region of heavy chain only antibodies may be used as the linker.

The peptide linker can be of any suitable length. In some embodiments, the peptide linker is at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 50, 75, 100 or more amino acids long. In some embodiments, the peptide linker is no more than about any of 100, 75, 50, 40, 35, 30, 25, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5 or fewer amino acids long. In some embodiments, the length of the peptide linker is any of about 1 amino acid to about 10 amino acids, about 1 amino acid to about 20 amino acids, about 1 amino acid to about 30 amino acids, about 5 amino acids to about 15 amino acids, about 10 amino acids to about 25 amino acids, about 5 amino acids to about 30 amino acids, about 10 amino acids to about 30 amino acids long, about 30 amino acids to about 50 amino acids, about 50 amino acids to about 100 amino acids, or about 1 amino acid to about 100 amino acids.

An essential technical feature of such peptide linker is that said peptide linker does not comprise any polymerization activity. The characteristics of a peptide linker, which comprise the absence of the promotion of secondary structures, are known in the art and described. A particularly preferred amino acid in context of the “peptide linker” is Gly. Furthermore, peptide linkers that also do not promote any secondary structures are preferred. The linkage of the domains to each other can be provided by, e.g., genetic engineering. Methods for preparing fused and operatively linked bispecific single chain constructs and expressing them in mammalian cells or bacteria are well-known in the art.

The peptide linker can be a stable linker, which is not cleavable by proteases, especially by Matrix metalloproteinases (MMPs) .

The linker can also be a flexible linker. Exemplary flexible linkers include glycine polymers (G) _n (SEQ ID NO: 19) , glycine-serine polymers (including, for example, (GS) _n (SEQ ID NO: 20) , (GSGGS) _n (SEQ ID NO: 21) , (GGGGS) _n (SEQ ID NO: 22) , and (GGGS) _n (SEQ ID NO: 23) , where n is an integer of at least one) , glycine-alanine polymers, alanine-serine polymers, and other flexible linkers known in the art. Glycine and glycine-serine polymers are relatively unstructured, and therefore may be able to serve as a neutral tether between components. Glycine accesses significantly more phi-psi space than even alanine, and is much less restricted than residues with longer side chains. The ordinarily skilled artisan will recognize that design of an antibody fusion protein can include linkers that are all or partially flexible, such that the linker can include a flexible linker portion as well as one or more portions that confer less flexible structure to provide a desired antibody fusion protein structure.

Furthermore, exemplary linkers also include the amino acid sequence of such as (GGGGS) _n (SEQ ID NO: 22) , wherein n is an integer between 1 and 8, e.g. (GGGGS) ₃ (SEQ ID NO:17) , (GGGGS) ₄ (SEQ ID NO: 18) , or (GGGGS) ₆ (SEQ ID NO: 24) . In some embodiments, the peptide linker comprises the amino acid sequence of (GSTSGSGKPGSGEGS) _n (SEQ ID NO: 25) , wherein n is an integer between 1 and 3.

Non-peptide linkers

Coupling of two moieties may be accomplished by any chemical reaction that will bind the two molecules so long as both components retain their respective activities, e.g., binding to Sclerostin and a second agent in an anti-Sclerostin multispecific antibody, respectively. This linkage can include many chemical mechanisms, for instance covalent binding, affinity binding, intercalation, coordinate binding and complexation. In some embodiments, the binding is covalent binding. Covalent binding can be achieved either by direct condensation of existing side chains or by the incorporation of external bridging molecules. Many bivalent or polyvalent linking agents may be useful in coupling protein molecules in this context. For example, representative coupling agents can include organic compounds such as thioesters, carbodiimides, succinimide esters, diisocyanates, glutaraldehyde, diazobenzenes and hexamethylene diamines. This listing is not intended to be exhaustive of the various classes of coupling agents known in the art but, rather, is exemplary of the more common coupling agents.

In some embodiments, non-peptide linkers used herein include: (i) EDC (1-ethyl-3- (3-dimethylamino-propyl) carbodiimide hydrochloride; (ii) SMPT (4-succinimidyloxycarbonyl-alpha-methyl-alpha- (2-pridyl-dithio) -toluene (Pierce Chem. Co., Cat. (21558G) ; (iii) SPDP (succinimidyl-6 [3- (2-pyridyldithio) propionamido] hexanoate (Pierce Chem. Co., Cat #21651G) ; (iv) Sulfo-LC-SPDP (sulfosuccinimidyl 6 [3- (2-pyridyldithio) -propianamide] hexanoate (Pierce Chem. Co. Cat. #2165-G) ; and (v) sulfo-NHS (N-hydroxysulfo-succinimide: Pierce Chem. Co., Cat. #24510) conjugated to EDC.

The linkers described above contain components that have different attributes, thus may lead to bispecific antibodies with differing physio-chemical properties. For example, sulfo-NHS esters of alkyl carboxylates are more stable than sulfo-NHS esters of aromatic carboxylates. NHS-ester containing linkers are less soluble than sulfo-NHS esters. Further, the linker SMPT contains a sterically hindered disulfide bond, and can form antibody fusion protein with increased stability. Disulfide linkages, are in general, less stable than other linkages because the disulfide linkage is cleaved in vitro, resulting in less antibody fusion protein available. Sulfo-NHS, in particular, can enhance the stability of carbodimide couplings. Carbodimide couplings (such as EDC) when used in conjunction with sulfo-NHS, forms esters that are more resistant to hydrolysis than the carbodimide coupling reaction alone.

III. Methods of preparation

In some embodiments, there is provided a method of preparing a bispecific construct or antibody moiety that specifically binds to Sclerostin and second antigen and a composition such as polynucleotide, nucleic acid construct, vector, host cell, or culture medium that is produced during the preparation of the bispecific construct or antibody moiety. The bispecific construct or antibody moiety or composition described herein may be prepared by a number of processes as generally described below and more specifically in the Examples.

Antibody Expression and Production

The antibodies (including anti-Sclerostin bispecific antibodies, anti-Sclerostin antibody moieties, and anti-RANKL antibody moiety) described herein can be prepared using any known methods in the art, including those described below and in the Examples.

Nucleic Acid Molecules Encoding antibody moieties

In some embodiments, there is provided a polynucleotide encoding any one of the bispecific constructs or antibody moieties described herein. In some embodiments, there is provided a polynucleotide prepared using any one of the methods as described herein. In some embodiments, a nucleic acid molecule comprises a polynucleotide that encodes a heavy chain or a light chain of an antibody moiety (e.g., anti-Sclerostin antibody moiety) . In some embodiments, a nucleic acid molecule comprises both a polynucleotide that encodes a heavy chain and a polynucleotide that encodes a light chain, of an antibody moiety (e.g., anti-Sclerostin antibody moiety) . In some embodiments, a first nucleic acid molecule comprises a first polynucleotide that encodes a heavy chain and a second nucleic acid molecule comprises a second polynucleotide that encodes a light chain.

In some such embodiments, the heavy chain and the light chain are expressed from one nucleic acid molecule, or from two separate nucleic acid molecules, as two separate polypeptides. In some embodiments, such as when an antibody is a scFv, a single polynucleotide encodes a single polypeptide comprising both a heavy chain and a light chain linked together.

In some embodiments, a polynucleotide encoding a heavy chain or light chain of an antibody moiety (e.g., anti-Sclerostin antibody moiety) comprises a nucleotide sequence that encodes a leader sequence, which, when translated, is located at the N terminus of the heavy chain or light chain. As discussed above, the leader sequence may be the native heavy or light chain leader sequence, or may be another heterologous leader sequence.

In some embodiments, the polynucleotide is a DNA. In some embodiments, the polynucleotide is an RNA. In some embodiments, the RNA is an mRNA.

Nucleic acid molecules may be constructed using recombinant DNA techniques conventional in the art. In some embodiments, a nucleic acid molecule is an expression vector that is suitable for expression in a selected host cell.

Nucleic acid construct

In some embodiments, there is provided a nucleic acid construct comprising any one of the polynucleotides described herein. In some embodiments, there is provided a nucleic acid construct prepared using any method described herein.

In some embodiments, the nucleic acid construct further comprises a promoter operably linked to the polynucleotide. In some embodiments, the polynucleotide corresponds to a gene, wherein the promoter is a wild-type promoter for the gene.

Vectors

In some embodiments, there is provided a vector comprising any polynucleotides that encode the heavy chains and/or light chains of any one of the antibody moieties described herein (e.g., anti-Sclerostin antibody moieties) or nucleic acid construct described herein. In some embodiments, there is provided a vector prepared using any method described herein. Vectors comprising polynucleotides that encode any of bispecific constructs such as antibodies, scFvs, fusion proteins or other forms of constructs described herein (e.g., anti-Sclerostin scFv) are also provided. Such vectors include, but are not limited to, DNA vectors, phage vectors, viral vectors, retroviral vectors, etc. In some embodiments, a vector comprises a first polynucleotide sequence encoding a heavy chain and a second polynucleotide sequence encoding a light chain. In some embodiments, the heavy chain and light chain are expressed from the vector as two separate polypeptides. In some embodiments, the heavy chain and light chain are expressed as part of a single polypeptide, such as, for example, when the antibody is a scFv.

In some embodiments, a first vector comprises a polynucleotide that encodes a heavy chain and a second vector comprises a polynucleotide that encodes a light chain. In some embodiments, the first vector and second vector are transfected into host cells in similar amounts (such as similar molar amounts or similar mass amounts) . In some embodiments, a mole-or mass-ratio of between 5: 1 and 1: 5 of the first vector and the second vector is transfected into host cells. In some embodiments, a mass ratio of between 1: 1 and 1: 5 for the vector encoding the heavy chain and the vector encoding the light chain is used. In some embodiments, a mass ratio of 1: 2 for the vector encoding the heavy chain and the vector encoding the light chain is used.

In some embodiments, a vector is selected that is optimized for expression of polypeptides in CHO or CHO-derived cells, or in NS0 cells.

Host Cells

In some embodiments, there is provided a host cell comprising any polypeptide, nucleic acid construct and/or vector described herein. In some embodiments, there is provided a host cell prepared using any method described herein. In some embodiments, the host cell is capable of producing any of antibody moieties described herein under a fermentation condition.

In some embodiments, the antibody moieties described herein (e.g., anti-Sclerostin antibody moieties) may be expressed in prokaryotic cells, such as bacterial cells; or in eukaryotic cells, such as fungal cells (such as yeast) , plant cells, insect cells, and mammalian cells. Such expression may be carried out, for example, according to procedures known in the art. Exemplary eukaryotic cells that may be used to express polypeptides include, but are not limited to, COS cells, including COS 7 cells; 293 cells, including 293-6E cells; CHO cells, including CHO-S, DG44. Lec13 CHO cells, and FUT8 CHO cells; cells (Crucell) ; and NS0 cells. In some embodiments, the antibody moieties described herein (e.g., anti-Sclerostin antibody moieties) may be expressed in yeast. See, e.g., U.S. Publication No. US 2006/0270045 A1. In some embodiments, a particular eukaryotic host cell is selected based on its ability to make desired post-translational modifications to the heavy chains and/or light chains of the antibody moiety. For example, in some embodiments, CHO cells produce polypeptides that have a higher level of sialylation than the same polypeptide produced in 293 cells.

Introduction of one or more nucleic acids into a desired host cell may be accomplished by any method, including but not limited to, calcium phosphate transfection, DEAE-dextran mediated transfection, cationic lipid-mediated transfection, electroporation, transduction, infection, etc. Nucleic acids may be transiently or stably transfected in the desired host cells, according to any suitable method.

The present application also provides host cells comprising any of the polynucleotides or vectors described herein. In some embodiments, the invention provides a host cell comprising an anti-Sclerostin antibody. Any host cells capable of over-expressing heterologous DNAs can be used for the purpose of isolating the genes encoding the antibody, polypeptide or protein of interest. Non-limiting examples of mammalian host cells include but not limited to COS, HeLa, and CHO cells. See also PCT Publication No. WO 87/04462. Suitable non-mammalian host cells include prokaryotes (such as E. coli or B. subtillis) and yeast (such as S. cerevisae, S. pombe; or K. lactis) .

In some embodiments, the antibody moiety is produced in a cell-free system.

Culture medium

In some embodiments, there is provided a culture medium comprising any antibody moiety, polynucleotide, nucleic acid construct, vector, and/or host cell described herein. In some embodiments, there is provided a culture medium prepared using any method described herein.

In some embodiments, the medium comprises hypoxanthine, aminopterin, and/or thymidine (e.g., HAT medium) . In some embodiments, the medium does not comprise serum. In some embodiments, the medium comprises serum. In some embodiments, the medium is a D-MEM or RPMI-1640 medium.

Purification of antibody moieties

The bispecific constructs (e.g., anti-Sclerostin monoclonal antibodies or multispecific antibodies) may be purified by any suitable method. Such methods include, but are not limited to, the use of affinity matrices or hydrophobic interaction chromatography. Suitable affinity ligands include the ROR1 ECD and ligands that bind antibody constant regions. For example, a Protein A, Protein G, Protein A/G, or an antibody affinity column may be used to bind the constant region and to purify a bispecific construct comprising an Fc fragment. Hydrophobic interactive chromatography, for example, a butyl or phenyl column, may also suitable for purifying some polypeptides such as antibodies. Ion exchange chromatography (e.g. anion exchange chromatography and/or cation exchange chromatography) may also suitable for purifying some polypeptides such as antibodies. Mixed-mode chromatography (e.g. reversed phase/anion exchange, reversed phase/cation exchange, hydrophilic interaction/anion exchange, hydrophilic interaction/cation exchange, etc. ) may also suitable for purifying some polypeptides such as antibodies. Many methods of purifying polypeptides are known in the art.

IV. Methods of Treatments

In some embodiments, there is provided a method of treating a disease or condition in an individual, comprising administering to the individual an effective mount of the bispecific construct or pharmaceutical composition described herein. In some embodiments, the disease or condition is a bone-related disorder or cartilage related disorder, a bone marrow or haemotological disorder, a musculoskeletal rare disease, a muscle-related disorder, or a cancer.

The methods described herein are applicable to any bone-related disease or condition. In some embodiments, the bone-related disorder is osteogenesis imperfecta, osteoporosis or osteopenia (in men and/or women) , osteonecrosis, delay bone healing, non-union bone fractures, multiple myeloma, multiple myeloma related bone disorders, primary bone tumor, bone metastasis of malignancies, solid tumor bone metastasis, inflammatory or infectious bone disease, osteomalacia, hypercalcemia, Paget’s disease, immobilization-induced bone loss, glucocorticoid-induced bone loss, inflammation-induced bone loss including arthritis-induced bone loss, spaceflight osteoporosis/osteopenia and bone loss caused by reduced gravity or other disease or condition associated with a) bone loss of either quantity or quality or both and/or b) abnormality of bone structure and quality. In some embodiments, the bone-related disorder is osteoporosis or osteopenia. In some embodiments, the bone-related disorder is osteogenesis imperfecta. In some embodiments, the bone-related disorder is multiple myeloma and multiple myeloma related bone disorders.

In some embodiments, the disease or condition is a cartilage disorder. In some embodiments, the cartilage disorder is chondromatosis, chondrodysplasia, achondroplasia, epiphyseal dysplasia, chondrodystrophic myotonia, juxtacortical chondroma, tear of cartilage of knee, osteofibrous dysplasia, osteoarthritis, osteogenesis imperfecta, hypophosphatemic rickets or osteochondrodystrophy.

In some embodiments, the disease or condition is a muscle-related disorder. In some embodiments, the muscle-related disorder is sarcopenia and cancer sarcopenia.

In some embodiments, the disease or condition is a cancer (e.g., a hematological malignancy, e.g., multiple myeloma) .

In some embodiments, there is provided a method of facilitation of heal after bone or joint surgeries in an individual, comprising administering to the individual an effective mount of the bispecific construct (such as any of the bispecific constructs described herein) .

In some embodiments, there is provided a method of treating a disease or condition (e.g., a bone-related disease) in an individual, comprising administering to the individual an effective mount of a bispecific construct comprising an antibody moiety comprising a heavy chain variable region (V_H) and a light chain variable region (V_L) , wherein the V_H comprises i) the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, ii) the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and iii) the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the HC-CDRs, and the V_L comprises i) the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4 or 26, ii) the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and iii) the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 6, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the LC-CDRs.

In some embodiments, there is provided a method of treating a disease or condition (e.g., a bone-related disease) in an individual, comprising administering to the individual an effective mount of an multispecific construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety specifically recognizes RANKL. In some embodiments, the first antibody moiety comprises a first heavy chain variable region (V_H-1) and a first light chain variable region (V_L-1) , wherein the V_H-1 comprises i) the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, ii) the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and iii) the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3 , or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the HC-CDRs, and the V_L-1 comprises i) the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4 or 26, ii) the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and iii) the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 6, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the LC-CDRs. In some embodiments, the second antibody moiety comprising a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) , wherein the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12.

In some embodiments, the subject is a mammal (such as a human) .

Dosing and Method of Administering the bispecific construct

The dosing regimen of the bispecific construct (such as the specific dosages and frequencies) used for treating a disease or disorder as described herein administered into the individual may vary with the particular bispecific construct (such as anti-Sclerostin monoclonal or multispecific antibodies, such as anti-Sclerostin fusion proteins) , the mode of administration, and the type of disease or condition being treated.

In some embodiments of any of the above aspects, the effective amount of a bispecific construct (such as anti-Sclerostin monoclonal or multispecific antibodies) is in the range of about 0.001 μg/kg to about 500 mg/kg of total body weight, for example, about 0.005 μg/kg to about 100 mg/kg, about 0.01 μg/kg to about 50 mg/kg, or about 0.01 μg/kg to about 5 mg/kg.

In some embodiments, the treatment comprises more than one administration of the bispecific constructs (such as about two, three, four, five, six, seven, eight, night, or ten administrations of bispecific constructs) . In some embodiments, the bispecific construct is administered at a frequency of about daily, weekly, two times per week, once a month, once every three months, once every six months, or once a year.

The bispecific construct can be administered to an individual (such as human) via various routes, including, for example, intravenous, intra-articular, intra-arterial, intraperitoneal, intrapulmonary, oral, inhalation, intravesicular, intramuscular, intra-tracheal, subcutaneous, intraocular, intrathecal, transmucosal, and transdermal. In some embodiments, the bispecific construct is included in a pharmaceutical composition while administered into the individual. In some embodiments, sustained continuous release formulation of the composition may be used. In some embodiments, the composition is administered intravenously. In some embodiments, the composition is administered intraperitoneally. In some embodiments, the composition is administered intravenously. In some embodiments, the composition is administered intraperitoneally. In some embodiments, the composition is administered intramuscularly. In some embodiments, the composition is administered subcutaneously. In some embodiments, the composition is administered intravenously. In some embodiments, the composition is administered orally.

Combination therapy

This application also provides methods of administering a bispecific construct into an individual for treating a disease or condition (such as a bone-related disease) , wherein the method further comprises administering a second agent or therapy. In some embodiments, the second agent or therapy is a standard or commonly used agent or therapy for treating the disease or condition.

In some embodiments, there is provided a method of treating a disease or condition (e.g., a bone-related disease) in an individual, comprising administering to the individual a) an effective mount of a bispecific construct (such as any of the bispecific constructs described herein) ; and b) a second therapy or agent. In some embodiments, the second therapy or agent is an anti-RANKL antibody. In some embodiments, the second agent or therapy comprises an agent selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , a bisphosphonate, a prostaglandin E (PGE) receptor agonist, VEGF, and TGFβ, growth factor (myostatin) and calcitonin.

In some embodiments, there is provided a method of treating a disease or condition (e.g., a bone-related disease) in an individual, comprising administering to the individual a) an effective mount of a bispecific construct (such as any of the bispecific constructs described herein) ; and b) an anti-RANKL antibody. In some embodiments, the bispecific construct comprises an antibody moiety comprising a heavy chain variable region (V_H) and a light chain variable region (V_L) , wherein the V_H comprises i) the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, ii) the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and iii) the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the HC-CDRs, and the V_L comprises i) the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4 or 26, ii) the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and iii) the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 6, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the LC-CDRs. In some embodiments, the anti-RANKL antibody comprises a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) , wherein the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12.

In some embodiments, the bispecific construct and the second agent or therapy are administered simultaneously. In some embodiments, the bispecific construct and the second agent or therapy are administered concurrently. In some embodiments, the bispecific construct and the second agent or therapy are administered sequentially.

V. Compositions, Kits and Articles of manufacture

Also provided herein are compositions (such as formulations, such as pharmaceutical compositions) comprising any one of the bispecific construct or anti-Sclerostin antibody moiety described herein, nucleic acid encoding the antibody moieties, vector comprising the nucleic acid encoding the antibody moieties, or host cells comprising the nucleic acid or vector.

In some embodiments, there is provided a pharmaceutical composition comprising a bispecific construct (such as any of the bispecific constructs described herein) and a pharmaceutically acceptable carrier. In some embodiments, the composition further comprises an agent selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , VEGF, TGFβ, growth factor (myostatin) and calcitonin.

Suitable formulations of the bispecific construct described herein can be obtained by mixing the bispecific construct or anti-Sclerostin antibody moiety having the desired degree of purity with optional pharmaceutically acceptable carriers, excipients or stabilizers (Remington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980) ) , in the form of lyophilized formulations or aqueous solutions. Acceptable carriers, excipients, or stabilizers are nontoxic to recipients at the dosages and concentrations employed, and include buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride, benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propylparaben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol) ; low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as olyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counter-ions such as sodium; metal complexes (e.g. Zn-protein complexes) ; and/or non-ionic surfactants such as TWEEN^TM, PLURONICS^TM or polyethylene glycol (PEG) . Lyophilized formulations adapted for subcutaneous administration are described in WO97/04801. Such lyophilized formulations may be reconstituted with a suitable diluent to a high protein concentration and the reconstituted formulation may be administered subcutaneously to the individual to be imaged, diagnosed, or treated herein.

The formulations to be used for in vivo administration must be sterile. This is readily accomplished by, e.g., filtration through sterile filtration membranes.

Also provided are kits comprising any one of the bispecific construct or anti-Sclerostin antibody moiety described herein. The kits may be useful for any of the methods of modulating cell composition or treatment described herein.

In some embodiments, there is provided a kit comprising a bispecific construct specifically binding to Sclerostin.

In some embodiments, the kit further comprises a device capable of delivering the bispecific construct into an individual. One type of device, for applications such as parenteral delivery, is a syringe that is used to inject the composition into the body of a subject. Inhalation devices may also be used for certain applications.

In some embodiments, the kit further comprises a therapeutic agent for treating a disease or condition, e.g., a bone-related disease, e.g., osteogenesis imperfecta, osteopetrosis, or a disease or condition associated with bone loss.

The kits of the present application are in suitable packaging. Suitable packaging includes, but is not limited to, vials, bottles, jars, flexible packaging (e.g., sealed Mylar or plastic bags) , and the like. Kits may optionally provide additional components such as buffers and interpretative information.

The present application thus also provides articles of manufacture. The article of manufacture can comprise a container and a label or package insert on or associated with the container. Suitable containers include vials (such as sealed vials) , bottles, jars, flexible packaging, and the like. Generally, the container holds a composition, and may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle) . The label or package insert indicates that the composition is used for imaging, diagnosing, or treating a particular condition in an individual. The label or package insert will further comprise instructions for administering the composition to the individual and for imaging the individual. The label may indicate directions for reconstitution and/or use. The container holding the composition may be a multi-use vial, which allows for repeat administrations (e.g. from 2-6 administrations) of the reconstituted formulation. Package insert refers to instructions customarily included in commercial packages of diagnostic products that contain information about the indications, usage, dosage, administration, contraindications and/or warnings concerning the use of such diagnostic products. Additionally, the article of manufacture may further comprise a second container comprising a pharmaceutically acceptable buffer, such as bacteriostatic water for injection (BWFI) , phosphate-buffered saline, Ringer's solution and dextrose solution. It may further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, and syringes.

The kits or article of manufacture may include multiple unit doses of the compositions and instructions for use, packaged in quantities sufficient for storage and use in pharmacies, for example, hospital pharmacies and compounding pharmacies.

Those skilled in the art will recognize that several embodiments are possible within the scope and spirit of this invention. The invention will now be described in greater detail by reference to the following non-limiting examples. The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

EXAMPLES

The examples below are intended to be purely exemplary of the application and should therefore not be considered to limit the application in any way. The following examples and detailed description are offered by way of illustration and not by way of limitation.

Example 1. Generation of bispecific antibodies

Bispecific antibodies that target both Sclerostin and RANKL were generated. See Tables 9 and 10 for sequences of the exemplary antibodies that target sclerostin and RANKL.

Table 9. CDR Sequences of exemplary anti-sclerostin antibodies

Table 10. CDR Sequences of exemplary anti-RANKL antibody

Specifically, the following Sclerostin/RANKL pairings were generated: hAb-1 x Denosumab, hAb-2 x Denosumab.

In one embodiment (see (A) of FIG. 2) , two heavy chains of anti-Sclerostin antibodies were transformed into ‘Knob-into-Hole’ asymmetric IgG structures. One anti-RANKL Denosumab Fv domain was transformed into scFvs with two different orientations of VH and VL, linked by a (GGGGS) 4 linker. There are mutations like G100C in VH and G44C in VL to facilitate correct assembly of scFv. One anti-RANKL scFv is linked to one of two IgG heavy chain C-termini of anti-Sclerostin humanized antibodies by one GGGGSGGGGSGGGGS (SEQ ID NO: 17) linker to form 2: 1 bispecific of IgG-scFv.

In another embodiment (see (B) of FIG. 2) , anti-Sclerostin antibodies and anti-RANKL Denosumab were transformed into ‘Knob-into-Hole’ bispecific antibodies with asymmetric IgG structure. The CL domain of anti-RANKL Denosumab contains mutations of S176C and C214S, and the CH1 domain contains mutations like F170C and C131S to form orthogonal CH₁-CK disulfide bond to enable light chains correct paring. A second anti-Sclerostin antibody Fab fragment is linked to first anti-Sclerostin heavy chain C-termini by one GGGGSGGGGSGGGGS (SEQ ID NO: 17) linker to form 2: 1 bispecific of IgG-Fab.

In another embodiment (see (C) of FIG. 2) , two heavy chains of anti-Sclerostin antibodies were transformed into ‘Knob-into-Hole’a symmetric IgG structures. One anti-sclerostin Fv domain was transformed into scFv with two different orientations of VH and VL, linked by a (GGGGS) 4 linker. One anti-RANKL Denosumab Fv domain was transformed into scFvs with two different orientations of VH and VL, linked by a (GGGGS) 4 linker. There are mutations like G100C in VH and G44C in VL to facilitate correct assembly of anti-RANKL or anti-sclerostin scFv. The anti-sclerostin scFv and anti-RANKL scFv are linked separately to two IgG heavy chains C-termini of anti-Sclerostin antibodies by one GGGGSGGGGSGGGGS (SEQ ID NO: 17) linker to form 3: 1 bispecific of IgG-scFv.

Table 3 below lists format and sequences of various anti-Sclerostin bispecific antibodies.

Table 3. Anti-Sclerostin x anti-RANKL bispecific antibodies

Bispecific molecules were transiently expressed in adherence-adapted 293 6E cells in 96-well plates. Adherent 293 6E cells were seeded in Poly-D-Lysine coated 96-well tissue culture plates at 5E4 cells per well in Serum-free KOP293 medium (Zhuhai Kairui Biotech #K03252) at 25 μg/ml, and 5%FBS 24 hours prior to the transfection and incubated overnight at 37 ℃ in 5%CO₂. On the day of transfection, 100 ng (40 ng/μl) of each corresponding HC and LC DNA of the binding molecules were mixed together. Serum-free media KOP293 25 μl/well was added to the DNA mixtures. After incubation at RT for 15-30 min, the transfection mixtures were added to the culture plates which were seeded the day before and mixed with gentle rocking motions. The culture plates were put back into the 37 ℃, 5%CO₂ incubator overnight. The next day, media and transfection mixtures were aspirated and replaced with 130 μl of serum free media containing 0.5% Tryptone. The plates were incubated for another 6 days. Conditioned media (CM) was harvested on day 7 after transfection. The plates were spun at 1000 rpm for 5 min to pellet any cell debris. Supernatants were carefully transferred into sterile polypropylene blocks.

Antibodies were purified by protein A affinity chromatography, and buffer exchanged in PBS (pH 7.2) . The concentrations of purified antibodies were determined by reading the absorbance at 280 nm using the theoretically determined extinction coefficient for that protein.

Example 2. The binding kinetics and affinities of anti-Sclerostin × anti-RANKL bispecific antibodies

Binding kinetics and affinities of anti-Sclerostin×anti-RANKL bispecific antibodies were measured with Gator (Probe Life) bio-layer interferometry (BLI) . Antibodies were immobilized on an anti-hFc biosensor, using a 5μg/ml solution. Serial dilutions of sclerostin (from 1μg/ml) and RANKL (from 4μg/ml) by two folds in kinetics buffer (PBS, pH 7.4, 0.05%Tween-20, 0.2%BSA) were used as the analytes. Affinity (K_D) and kinetic parameters (K_on and K_off) were calculated from a global fit (1: 1) of the data using the Gator software. The results are summarized in Table 4.

Table 4. Summary of binding kinetics of the bispecific antibodies to human Sclerostin, and RANKL

a Limit of detection, which indicates the off-rate is very slow and beyond the quantification limit of Gator

b The affinity K_D values are calculated by K_off/K_on, in the case that K_off is LOD, the K_D values are estimated around 10pM, which is the detection limit of Gator

Example 3. In vitro sclerostin-and RANKL-neutralization activity

[Rectified under Rule 91, 05.09.2023]
The exemplified bispecific antibodies were capable of neutralizing sclerostin and blocking Wnt1 induced TCF/LEF luciferase activity, as determined in an HEK293 based assay. Addition of sclerostin antagonizes the Wnt1 signal, resulting in diminished luciferase activity. Conversely, addition of sclerostin antibody will block the diminished signal and restore the luciferase activities. The HEK293/TCF/LEF/Wnt1 cell line was obtained from Askgene (Askgene, CA) . Upon arrival, cells were cultured in RPMI1640 culture medium with L-glutamine (Life Technologies, CA) , containing 10%fetal bovine serum (FBS) , non-essential amino acids, sodium pyruvate, 2-merceptoethanol, 1%penicillin/streptomycin, 400 μg/ml G418, and 2 μg/ml puromycin. Cells were harvested and plated into a white 96-well plate, at a concentration of 30,000 cells/well. When testing the inhibitory effect of the antagonist, the culture medium was removed and 50 μl of assay medium (culture medium without G418 and puromycin) containing 10 mM LiCl, was added into each well. When testing the neutralization activities of the antibodies, a serial dilution of the exemplified antibodies was made in assay medium. A fixed amount of sclerostin protein was added and incubated for 15 minutes, the final concentrations in each well for sclerostin are 1 μg/ml, and the titrated concentrations of bispecific antibodies are 400, 200, 100, 50, 25, 12.5, and 6.25 nM. Then, 50 μl of the medium was transferred into assay plate, incubated for 6 hours at 37 ℃ with 5%CO₂, 100 μl/well Bio-Lite fluorescent reaction reagent was added, and the relative luminescence units (RLU) were recorded using BioTek Gen5 luminescence microplate reader. The EC₅₀s were calculated by fitting the four-parameter dose-response curves from three replicated concentrations.

The exemplified bispecific antibodies were capable of neutralizing RANKL in a RAW264.7 cell line stably expressing luciferase reporter gene under the control of nuclear factor-κB (NF-κB) response elements. The RAW264.7 cells were purchased from ATCC and were transfected with the vector of pCM1.1 (Luc/NF-κB/Hygro) , followed by selection of 150 mg/ml hygromycin B 24 h post transfection. The parental RAW264.7 cells were maintained in DMEM with 10%FBS, 1%P/S, 1%glutamine, while the transgenic cells NF-κB-Luci RAW264.7 cells were cultured in DMEM with 10%FBS, 1%P/S, 1%glutamine and 150 mg/ml hygromycin B. During the bioassay, DMEM medium containing 10%FBS was employed as the assay medium. The hygromycin resistant stable pool was then subcloned by limited dilution, and various single cell derived variants were further screened by the addition of RANKL and the measurement of luciferase expression to choose the best responsive variant (NF-κB-Luci RAW264.7 cells) .

NF-kB-Luci RAW264.7 cells were seeded at the density of 8×10⁴ cells in 50 ml assay medium per well. Exemplified bispecific antibodies were sequentially diluted using assay medium mixed with 0.6 μg/ml human recombinant RANKL into 8 concentrations with the starting concentration of 900 nM. The eight serially diluted samples were added at the volume of 50 ml per well, followed by incubation at 37 ℃ and 5%CO₂ for 24 h. After addition of 100 μl per well of the Bio-Lite fluorescent reaction reagent, relative luciferase units (RLU) were recorded using BioTek Gen5 luminescence microplate reader. The EC₅₀s were calculated by fitting the four-parameter dose-response curves from three replicated concentrations.

All bispecific antibodies were able to fully neutralize Wnt-antagonizing effect from sclerostin and NF-κB activation effect from RANKL in a dose dependent manner. The EC₅₀ activities as shown in Table 5.

Table 5. Sclerostin neutralization activity in HEK293/TCF/LEF/Wnt1 reporter gene assay, and RANKL neutralization activity in RAW264.7/NF-kB/Luc-Hygro reporter gene assay for bispecific antibodies

Example 4. Pharmacodynamics study of bispecific antibodies

The bone formation biomarker procollagen type I N-terminal propeptide (P1NP) as well as bone resorption biomarker C-terminal end of the telopeptide of type I collagen (CTX-1) are two widely accepted specific bone homeostatic indicators. To test the pharmacodynamic effects of the bispecific antibodies, normal male cynomolgus monkeys were subjected subcutaneous injection of different bispecific antibodies described above. The blood samples were obtained on day 3 after the injection. Serum samples were then separated by centrifugation. Serum P1NP and CTX-1 levels were measured using P1NP Test Kit and Serum CrossLaps ELISA kit respectively following the manufacturer’s instruction. The results showed that the administration of bispecific antibody caused a dramatic increase in serum P1NP levels only 3 days after the injection. When compared to the pre-dose baseline, serum P1NP levels at day 3 were increased between 43.18 ± 4.3 %and 86.61 ± 26.2%for different bispecific antibodies (Table 6) . Moreover, the serum CTX-1 levels decreased between 63.07 ± 5.8%and -96.31 ± 1.6 %for different bispecific antibodies (Table 6) compared to the baseline in response to bispecific antibody injection on day 3. This result indicated that the bispecific antibodies could robustly increase bone formation and decrease bone resorption simultaneously, suggesting their profound therapeutic efficacy to treat diseases or conditions associated with low bone mass or poor bone quality such as osteopenia or osteoporosis in both men and women, osteogenesis imperfecta, multiple myeloma bone diseases, and solid tumor bone metastasis. It is difficult for anti-Sclerostin (e.g., hAb-2) or anti-RANKL (e.g., Denosumab) mAbs to simultaneously cause a significant increase in P1NP and a decrease in CTX-1. The present invention finds that the structure and sequence design of the bispecific antibody have a significant impact on both bone marker serum concentrations at the same time, wherein the structure and sequence of the 2: 1 IgG-Fab (BAP0079) bispecific antibody achieved unexpected technical effects with optimal increase of P1NP and the decrease of CTX-1 even at much lower dose comparing with other bispecific antibodies. Data was shown in Table 6.

Table 6. The serum concentrations of P1NP and CTX-1 in cynomolgus monkeys 3 days after injection.

Example 5. Bispecific antibodies show therapeutic efficacy in multiple myeloma bone disease mouse model.

The bispecific antibodies are also evaluated in MM. 1S mice human multiple myeloma bone disease (MMBD) model. For the establishment of the animal model, immunocompromised mice (NCG) were used in the study. Male NCG mice of six weeks old were purchased and housed in SPF condition. MM tumor cells, MM. 1S-Luc, were used and 2.5 million of cells were tail vein inoculated into NCG mice. One week later, the mice were subjected to live imaging to visualize the tumor cells migrated into bone marrow. The antibodies were then given subcutaneously twice a week for 4 weeks at 50 mg/kg. Bone samples were collected four weeks after the treatment for μCT analysis of vertebral and femoral bones for bone mass, strength, and structural changes. In vivo tumor burden was accessed at the end of treatment using live bioluminescence imaging system. All data were expressed as mean ± standard error of mean (SEM) and analyzed by one-way analysis of variance (ANOVA) with uncorrected Fisher’s LSD test. vs the control group.

Tail vein injection of MM. 1s cells showed larger amount of tumor cells accumulated in bone marrow, indicating the establishment of MMBD. μCT analysis revealed that the tumor cells have caused a large amount of bone lesions particularly in proximal and distal femoral trabecular bones. Bispecific antibodies treated for 4 weeks caused a dramatic reduction of bone lesions. In addition, it caused a marked increases in trabecular and cortical bone of the distal femur. The trabecular relative bone volume (BV/TV) in bispecific antibody treatment vs. control group is 73.17 ± 3.11 %vs. 29.31 ± 2.86 % (p < 0.0001) , and cortical BV/TV in bispecific antibody treatment vs. control group is 34.12 ± 1.06 %vs. 22.27 ± 1.16 % (p < 0.0001) . The trabecular bone marrow density (BMD) in bispecific antibody treatment vs. control group is 0.50 ± 0.02 vs. 0.17 ± 0.03 (p < 0.0001) , and cortical BMD in bispecific antibody treatment vs. control group is 0.22 ± 0.01 vs. 0.14 ± 0.01 (p < 0.0001) . These results suggested the profound therapeutic efficacy of bispecific antibody to treat diseases or conditions associated with low bone mass or poor bone quality such as bone metastasis of malignancies and/or solid tumor bone metastasis. Meanwhile, a significant reduction of tumor burden in bioluminescence imaging for the treatment group animals comparing to control group (total flux 1.24 × 10¹⁰ p/s vs. 1.77 × 10¹⁰ p/s, p < 0.05) indicated the tumor growth and migration can be inhibited by the bispecific antibody.

Example 6. Accelerated degradation analysis.

Exemplified bispecific antibodies were solved at 10 mg/ml in buffering solution, and then placed in a constant temperature and humidity chamber at 40 ℃ protected from light and incubated for 0, 7 and 14 days before sampling for examination. Samples are analyzed for percent high molecular weight (%HMW) soluble aggregate using SEC. There were less than 10%increase in HMW soluble aggregate formation tested by SEC. These results demonstrate the exemplified bispecific antibodies of the present invention, under 10 nM concentration, is stable in high temperature of 40 ℃ for at least 14 days.

Example 7. Repeated freeze /thaw analysis

Repeated freeze /thaw analysis of the exemplified bispecific antibodies is assessed with proteins concentrated at 10 mg/ml in buffering formulations. Four freeze /thaw cycles (a single cycle including incubation at -80 ℃ for 24 hours, followed by thawing at 25 ℃, then gentle mixing) are performed and percent high molecular weight (%HMW) soluble aggregate using SEC is assessed. There were less than a 10 %increase in HMW soluble aggregate formation. These results demonstrate the exemplified bispecific antibodies of the present invention, under 10 nM concentration, is stable following multiple freeze /thaw cycles.

Example 8. Oxidation resistance analysis

Oxidation resistance of the exemplified bispecific antibodies is assessed with proteins concentrated at 10 mg/ml in buffering formulations with 0.1%tert-Butyl hydroperoxide (tBHP) added as oxidant. The exemplified proteins were placed in a constant temperature and humidity chamber at 25 ℃ protected from light and incubated for 7 days before sampling for examination of percent high molecular weight (%HMW) soluble aggregate using SEC. There were less than a 10 %increase in HMW soluble aggregate formation. These results demonstrate the exemplified bispecific antibodies of the present invention, under 10 nM concentration, is stable in oxidative environment.

SEQUENCE TABLE

Claims

A bispecific construct comprising a first antibody moiety that specifically recognizes Sclerostin and a second antibody moiety that specifically recognizes RANKL, wherein the molar ratio of the first antibody moiety and the second antibody moiety is higher than 1: 1, wherein the first antibody moiety binds to an epitope on Sclerostin, wherein the epitope comprises the amino acid sequence set forth in SEQ ID NO: 35.
The bispecific construct of claim 1, wherein the molar ratio of the first antibody moiety and the second antibody moiety is from 2: 1 to 5: 1; preferably 2: 1 or 3: 1.
The bispecific construct of claim 1 or claim 2, wherein the first antibody moiety comprises a heavy chain variable region (V_H) and a light chain variable region (V_L) , the second antibody moiety comprises a second heavy chain variable region (V_H-2) and a second light chain variable region (V_L-2) .
The bispecific construct of claim 3, wherein the construct comprises:

a) a first polypeptide comprising a common light chain comprising, from N-terminus to C-terminus, i) a light chain variable region (V_L) , ii) a light chain constant domain;

b) a second polypeptide comprising a first heavy chain comprising, from N-terminus to C-terminus, i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, and iii) a first Fc domain; or i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a first Fc domain; and iv) a scFv fragment comprising the V_H and the V_L,

c) a third polypeptide comprising a second heavy chain comprising, from N-terminus to C-terminus, i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a second Fc domain; and iv) a scFv fragment comprising the V_H-2 and the V_L-2,

wherein the first and the second Fc domains form an Fc fragment.
The bispecific construct of claim 3, wherein the construct comprises:

a) a first and second polypeptide comprising a common light chain comprising, from N-terminus to C-terminus, i) a light chain variable region (V_L) , ii) a light chain constant domain;

b) a third polypeptide comprising a first heavy chain comprising, from N-terminus to C-terminus, i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a first Fc domain, iv) a heavy chain variable region (V_H) , and v) a heavy chain constant domain; or i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a heavy chain variable region (V_H) , iv) a heavy chain constant domain, v) a first Fc domain;

c) a fourth polypeptide comprising a second heavy chain comprising, from N-terminus to C-terminus, i) the V_H-2, ii) a heavy chain constant domain, and iii) a second Fc domain; or i) the V_H-2, ii) a heavy chain constant domain, and iii) a second Fc domain, iv) a heavy chain variable region (V_H) , and v) a heavy chain constant domain;

d) a fifth polypeptide comprising a second light chain comprising, from N-terminus to C-terminus, i) the V_L-2, ii) a light chain constant domain;

wherein the first and the second Fc domains form an Fc fragment.
The bispecific construct of claim 4 or claim 5, wherein one of the first and the second Fc domains comprises a T366W mutation, and optionally a S354C mutation, and wherein the other Fc domain comprises a T366S mutation, a L368A mutation, a Y407V mutation, and optionally a Y349C mutation, wherein numbering is according to the EU index.
The bispecific construct of any one of claims 1-6, the first antibody moiety comprises a heavy chain variable region (V_H) and a light chain variable region (V_L) , wherein:

the V_H comprises a HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, a HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and a HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the HC-CDRs; and

the V_L comprises a LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4 or 26, a LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and a LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 6, or a variant thereof comprising up to 5, 4, 3, 2, or 1 amino acid substitutions in the LC-CDRs.
The bispecific construct of any one of claims 1-7, wherein the first antibody moiety comprises a heavy chain variable region (V_H) and a light chain variable region (V_L) , wherein:

a) the V_H comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3; and the V_L comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 4, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and the LC-CDR3 comprising the amino acid sequence of any one of SEQ ID NO: 6, or

b) the V_H comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 1, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 3; and the V_L comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 26, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and the LC-CDR3 comprising the amino acid sequence of any one of SEQ ID NO: 6.
The bispecific construct of any one of claims 1-8, wherein the first antibody moiety comprises a heavy chain variable region (V_H) and a light chain variable region (V_L) , wherein:

a) a HC-CDR1, a HC-CDR2, and a HC-CDR3, respectively comprising the amino acid sequences of a CDR1, a CDR2, and a CDR3 within the V_H having the sequence set forth in SEQ ID NO: 27, and a LC-CDR1, a LC-CDR2, and a LC-CDR3, respectively comprising the amino acid sequences of a CDR1, a CDR2, and a CDR3 within the V_L having the sequence set forth in SEQ ID NO: 28; or

b) a HC-CDR1, a HC-CDR2, and a HC-CDR3, respectively comprising the amino acid sequences of a CDR1, a CDR2, and a CDR3 within the V_H having the sequence set forth in SEQ ID NO: 27, and a LC-CDR1, a LC-CDR2, and a LC-CDR3, respectively comprising the amino acid sequences of a CDR1, a CDR2, and a CDR3 within the V_L having the sequence set forth in SEQ ID NO: 29.
The bispecific construct of any one of claims 1-9, wherein the first antibody moiety comprises a heavy chain variable region (V_H) and a light chain variable region (V_L) , wherein the V_H comprises an amino acid sequence of SEQ ID NO: 27, or a variant comprising an amino acid sequence having at least about 80%sequence identity; and/or wherein the V_L comprises an amino acid sequence of SEQ ID NO: 28 or 29 or a variant comprising an amino acid sequence having at least about 80%sequence identity.
The bispecific construct of claim 10, wherein:

a) the V_H comprises an amino acid sequence of SEQ ID NO: 27, or a variant comprising an amino acid sequence having at least about 80%sequence identity; and the V_L comprises an amino acid sequence of SEQ ID NO: 28, or a variant comprising an amino acid sequence having at least about 80%sequence identity; or

b) the V_H comprises an amino acid sequence of SEQ ID NO: 27, or a variant comprising an amino acid sequence having at least about 80%sequence identity; and the V_L comprises an amino acid sequence of SEQ ID NO: 29, or a variant comprising an amino acid sequence having at least about 80%sequence identity.
The bispecific construct of any one of claims 1-11, wherein the RANKL is human RANKL.
The bispecific construct of any one of claims 3-12, wherein the V_H-2 comprises the HC-CDR1 comprising the amino acid sequence of SEQ ID NO: 7, the HC-CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and the HC-CDR3 comprising the amino acid sequence of SEQ ID NO: 9, and the V_L-2 comprises the LC-CDR1 comprising the amino acid sequence of SEQ ID NO: 10, the LC-CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and the LC-CDR3 comprising the amino acid sequence of SEQ ID NO: 12.
The bispecific construct of claims 13, wherein the V_H-2 comprises an amino acid sequence of SEQ ID NO: 13, or a variant comprising an amino acid sequence having at least about 80%sequence identity; and the V_L-2 comprises an amino acid sequence of SEQ ID NO: 14, or a variant comprising an amino acid sequence having at least about 80%sequence identity.
The bispecific construct of any one of claims 1-14, wherein the construct comprises:

a) a first polypeptide comprising a common light chain comprising, from N-terminus to C-terminus, i) the V_L, ii) a light chain constant domain;

b) a second polypeptide comprising a first heavy chain comprising, from N-terminus to C-terminus, i) the V_H, ii) a heavy chain constant domain, and iii) a first Fc domain; or i) a heavy chain variable region (V_H) , ii) a heavy chain constant domain, iii) a first Fc domain; and iv) a scFv fragment comprising the V_H and the V_L according to any one of claims 7-11;

c) a third polypeptide comprising a second heavy chain comprising, from N-terminus to C-terminus, i) the V_H, ii) a heavy chain constant domain, iii) a second Fc domain; and iv) a scFv fragment comprising the V_H-2 according to claim 13 or claim 14 and the V_L-2 according to claim 13 or claim 14,

wherein the first and the second Fc domains form an Fc fragment.
The bispecific construct of any one of claims 4 and 6-15, comprising:

1) the first polypeptide comprises the amino acid sequence of SEQ ID NO: 30, the second polypeptide comprises the amino acid sequence of SEQ ID NO: 33, and the third polypeptide comprises the amino acid sequence of SEQ ID NO: 34;

2) the first polypeptide comprises the amino acid sequence of SEQ ID NO: 30, the second polypeptide comprises the amino acid sequence of SEQ ID NO: 36, and the third polypeptide comprises the amino acid sequence of SEQ ID NO: 37;

3) the first polypeptide comprises the amino acid sequence of SEQ ID NO: 30, the second polypeptide comprises the amino acid sequence of SEQ ID NO: 42, and the third polypeptide comprises the amino acid sequence of SEQ ID NO: 43; or

4) the first polypeptide comprises the amino acid sequence of SEQ ID NO: 30, the second polypeptide comprises the amino acid sequence of SEQ ID NO: 46, and the third polypeptide comprises the amino acid sequence of SEQ ID NO: 47.
The bispecific construct of any one of claims 1-14, wherein the construct comprises:

a) a first and second polypeptide comprising a common light chain comprising, from N-terminus to C-terminus, i) the V_L, ii) a light chain constant domain;

b) a third polypeptide comprising a first heavy chain comprising, from N-terminus to C-terminus, i) the V_H, ii) a heavy chain constant domain, iii) a first Fc domain, iv) the V_H, and v) a heavy chain constant domain; or i) the V_H, ii) a heavy chain constant domain, iii) the V_H, iv) a heavy chain constant domain, v) a first Fc domain;

c) a fourth polypeptide comprising a second heavy chain comprising, from N-terminus to C-terminus, i) the V_H-2 according to claim 13 or claim 14, ii) a heavy chain constant domain, and iii) a second Fc domain; or i) the V_H-2 according to claim 13 or claim 14, ii) a heavy chain constant domain, and iii) a second Fc domain, iv) the V_H, and v) a heavy chain constant domain;

d) a fifth polypeptide comprising a second light chain comprising, from N-terminus to C-terminus, i) the V_L-2 according to claim 13 or claim 14, ii) a light chain constant domain; wherein the first and the second Fc domains form an Fc fragment.
The bispecific construct of any one of claims 5-14 and 17, comprising:

1) the first and second polypeptide comprises the amino acid sequence of SEQ ID NO: 31, the third polypeptide comprises the amino acid sequence of SEQ ID NO: 38, the fourth polypeptide comprises the amino acid sequence of SEQ ID NO: 39, the fifth polypeptide comprises the amino acid sequence of SEQ ID NO: 32;

2) the first and second polypeptide comprises the amino acid sequence of SEQ ID NO: 31, the third polypeptide comprises the amino acid sequence of SEQ ID NO: 38, the fourth polypeptide comprises the amino acid sequence of SEQ ID NO: 41, the fifth polypeptide comprises the amino acid sequence of SEQ ID NO: 32;

3) the first and second polypeptide comprises the amino acid sequence of SEQ ID NO: 31, the third polypeptide comprises the amino acid sequence of SEQ ID NO: 40, the fourth polypeptide comprises the amino acid sequence of SEQ ID NO: 41, the fifth polypeptide comprises the amino acid sequence of SEQ ID NO: 32; or

4) the first and second polypeptide comprises the amino acid sequence of SEQ ID NO: 31, the third polypeptide comprises the amino acid sequence of SEQ ID NO: 44, the fourth polypeptide comprises the amino acid sequence of SEQ ID NO: 45, the fifth polypeptide comprises the amino acid sequence of SEQ ID NO: 32.
The bispecific construct of any one of claims 1-18, wherein the antibody moiety is an antibody or antigen-binding fragment thereof selected from the group consisting of a full-length antibody, a bispecific antibody, a single-chain Fv (scFv) fragment, a Fab fragment, a Fab’ fragment, a F (ab’) ₂, an Fv fragment, a disulfide stabilized Fv fragment (dsFv) , a disulfide stabilized scFv (dsscFv) , a (dsFv) ₂, a Fv-Fc fusion, a scFv-Fc fusion, a scFv-Fv fusion, a diabody, a tribody, and a tetrabody.
The bispecific construct of any one of claims 1-19, wherein the construct is a full-length antibody comprising an Fc fragment.
The bispecific construct of claim 20, wherein the antibody moiety is a scFv fragment.
The bispecific construct of any one of claims 1-21, wherein the Sclerostin is a human Sclerostin.
The bispecific construct of any one of claims 1-3, and 5-22, wherein the second antibody moiety is a full-length antibody, a Fab, a Fab’, a (Fab’) ₂, an Fv, a single chain Fv (scFv) fragment, an scFv-scFv, a minibody, a diabody, or an sdAb.
The bispecific construct of claim 23, wherein the second antibody moiety is a full-length antibody comprising two heavy chains, two light chains and a Fc fragment, and wherein the first antibody moiety is a single chain Fv (scFv) fragment comprising the V_H fused with the V_L.
The bispecific construct of claim 24, wherein the first antibody moiety is fused to one or both of the heavy chains of the full-length antibody.
The bispecific construct of any one of claims 23-25, wherein the first antibody moiety is fused to one or both of the light chains of the full-length antibody.
The bispecific construct of claim 25 or 26, wherein the first antibody moiety is fused to N-terminus of the one or both of the heavy chains or light chains of the full-length antibody.
The bispecific construct of any one of claims 25-27, wherein the first antibody moiety is fused to C-terminus of the one or both of the heavy chains or light chains of the full-length antibody.
The bispecific construct of any one of claims 25-28, wherein the first antibody moiety is fused to the full-length antibody via a first linker.
The bispecific construct of any one of claims 25-28, wherein the first antibody moiety is fused to the full-length antibody without a linker.
The bispecific construct of claim 29, wherein the first linker is a GS linker selected from the group consisting of SEQ ID NOs: 15-25.
The bispecific construct of any one of claims 23-31, wherein the V_H is fused with the V_L via a second linker.
The bispecific construct of claim 32, wherein the scFv fragment comprises, from N-terminus to C-terminus, the V_H, the second linker, and the V_L.
The bispecific construct of claim 33, wherein the scFv fragment comprises, from N-terminus to C-terminus, the V_L, the second linker, and the V_H, and optionally a C-terminal alanine residue.
The bispecific construct of any one of claims 32-34, wherein the second linker comprises an amino acid sequence of SEQ ID NO: 17 or 18.
The bispecific construct of any one of claims 1-35, wherein the second antibody moiety is a scFv fragment comprising the V_H-2 and the V_L-2, and wherein the first antibody moiety is a full-length antibody comprising two heavy chains, two light chains and a Fc fragment.
The bispecific construct of claim 36, wherein the second antibody moiety is fused to one or both of the heavy chains of the full-length antibody.
The bispecific construct of claim 36 or 37, wherein the second antibody moiety is fused to one or both of the light chains of the full-length antibody.
The bispecific construct of claim 37 or 38, wherein the second antibody moiety is fused to N-terminus of the one or both of the heavy chains or light chains of the full-length antibody.
The bispecific construct of any one of claims 36-39, wherein the second antibody moiety is fused to C-terminus of the one or both of the heavy chains or light chains of the full-length antibody.
The bispecific construct of any one of claims 36-40, wherein the second antibody moiety is fused to the full-length antibody via a first linker.
The bispecific construct of any one of claims 36-41, wherein the second antibody moiety is fused to the full-length antibody without a linker.
The bispecific construct of claim 41, wherein the first linker is a GS first linker selected from the group consisting of SEQ ID NOs: 15-25.
The bispecific construct of any one of claims 36-43, wherein the V_H-2 is fused with the V_L-2 via a second linker.
The bispecific construct of any one of claims 36-43, wherein the V_H-2 is fused with the V_L-2 without a linker.
The bispecific construct of claim 44, wherein the scFv fragment comprises, from N-terminus to C-terminus, the V_H-2, the second linker, and the V_L-2.
The bispecific construct of claim 44, wherein the scFv fragment comprises, from N-terminus to C-terminus, the V_L-2, the second linker, and the V_H-2, and optionally a C-terminal alanine residue.
The bispecific construct of any one of claims 44 and 46-47, wherein the second linker comprises an amino acid sequence of SEQ ID NO: 17 or 18.
The bispecific construct of any one of claims 1-48, wherein the second moiety comprises a half-life extending moiety.
The bispecific construct of claim 49, wherein the half-life extending moiety is an Fc fragment.
The bispecific construct of any one of claims 2-50, wherein the Fc fragment is selected from the group consisting of Fc fragments form IgG, IgA, IgD, IgE, IgM, and combinations and hybrids thereof.
The bispecific construct of claim 51, wherein the Fc fragment is selected from the group consisting of Fc fragments from IgG1, IgG2, IgG3, IgG4, and combinations and hybrids thereof.
The bispecific construct of claim 51 or claim 52, wherein the Fc fragment comprises a H435R mutation and an Y436F mutation.
The bispecific construct of any one of claims 51-53, wherein the Fc fragment has a reduced effector function as compared to the corresponding wildtype Fc fragment.
The bispecific construct of any one of claims 52-54, wherein the Fc fragment has:

a) an enhanced effector function as compared to the corresponding wildtype Fc fragment, and/or

b) an enhanced FcRn binding affinity as compared to the corresponding wildtype Fc fragment.
The bispecific construct of any one of claims claim 1-55, wherein the construct is an antibody-drug conjugate or antibody fusion protein.
The bispecific construct of claim 56, wherein the second moiety comprises an agent or agents selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , a bisphosphonate, a prostaglandin E (PGE) receptor agonist, VEGF, TGFβ, growth factor (myostatin) , calcitonin, and combinations thereof.
A bispecific construct that specifically binds to Sclerostin and RANKL competitively with the bispecific construct of any one of claims 1-57.
A pharmaceutical composition comprising the bispecific construct of any one of claims 1-58 and a pharmaceutically acceptable carrier.
The pharmaceutical composition of claim 59, wherein the composition further comprises an agent or agents selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , VEGF, and TGFβ, growth factor (myostatin) , calcitonin, and combinations thereof.
An isolated nucleic acid encoding the bispecific construct of any one of claims 1-58.
A vector comprising the isolated nucleic acid of claim 61.
An isolated host cell comprising the isolated nucleic acid of claim 61, or the vector of claim 62.
A method of producing an anti-Sclerostin construct comprising:

a) culturing the isolated host cell of claim 63 under conditions effective to express the bispecific construct or a portion thereof; and

b) obtaining the expressed bispecific construct or a portion thereof from the host cell.
A method of treating and/or preventing a disease or condition in an individual, comprising administering to the individual an effective mount of the bispecific construct of any one of claims 1-58, and/or the pharmaceutical composition of claim 59 or claim 60.
The method of claim 65, wherein the disease or condition is a bone-related disorder or cartilage related disorder, a bone marrow or haemotological disorder, a musculoskeletal rare disease, a muscle-related disorder, or a cancer.
The method of claim 66, wherein the bone-related disorder is osteogenesis imperfecta, osteoporosis or osteopenia (in men and women) , osteonecrosis, delay bone healing, non-union bone fractures, multiple myeloma, multiple myeloma related bone disorders, primary bone tumor, bone metastasis of malignancies, solid tumor bone metastasis, inflammatory or infectious bone disease, osteomalacia, hypercalcemia, Paget’s disease, immobilization-induced bone loss, glucocorticoid-induced bone loss, inflammation-induced bone loss including arthritis-induced bone loss, spaceflight osteoporosis/osteopenia and bone loss caused by reduced gravity or other disease or condition associated with a) bone loss of either quantity or quality or both and/or b) abnormality of bone structure and quality.
The method of claim 67, wherein the bone-related disorder is osteoporosis or osteopenia.
The method of claim 67, wherein the bone-related disorder is osteogenesis imperfecta.
[Corrected under Rule 26, 02.06.2023]
The method of claim 67, wherein the bone-related disorder is multiple myeloma and multiple myeloma related bone disorders.
[Corrected under Rule 26, 02.06.2023]
The method of claim 66, wherein the cartilage disorder is chondromatosis, chondrodysplasia, achondroplasia, epiphyseal dysplasia, chondrodystrophic myotonia, juxtacortical chondroma, tear of cartilage of knee, osteofibrous dysplasia, osteoarthritis, osteogenesis imperfecta, hypophosphatemic rickets or osteochondrodystrophy.
The method of claim 66, wherein the muscle-related disorder is sarcopenia and cancer sarcopenia.
A method of facilitation of heal after bone or joint surgeries in an individual, comprising administering to the individual an effective mount of the anti-Sclerostin construct of any one of claims 1-58, and/or the pharmaceutical composition of claim 59 or claim 60.
The method of any one of claims 65-73, wherein the bispecific construct is administered by subcutaneous injection, intravenous injection, intramuscular injection or administered orally or parenterally into the individual.
The method of any one of claims 65-74, wherein the method further comprises administering a second agent or therapy.
The method of claim 75, wherein the second agent or therapy comprises an anti-RANKL antibody.
The method of claim 75, wherein the second agent or therapy comprises an agent selected from the group consisting of a parathyroid hormone (PTH) , a selective estrogen receptor modulator (SERM) , a bisphosphonate, a prostaglandin E (PGE) receptor agonist, VEGF, TGFβ, growth factor (myostatin) and calcitonin.
The method of any one of claims 65-77, wherein the individual is a human.