Fcrn-binding molecules and methods of use

Abstract

Provided herein are binding molecules comprising a human neonatal Fc receptor (FcRn) binding molecule and a moiety that does not specifically bind to a human antigen. Also provided herein are polynucleotides, vectors, host cells, and methods of production. Further provided herein are methods of treating an antibody-mediated disorder with a FcRn-binding molecule or a FcRn / antigen-binding molecule.

Description

Technical Field

[0001] The present disclosure relates to human neonatal Fc receptor (FcRn) binding molecules and methods of use thereof. Background Art

[0002] Immunoglobulin gamma (IgG) antibodies play a key role in the pathology of many disorders, such as autoimmune diseases, inflammatory diseases, and disorders in which the pathology is characterized by overexpression of IgG antibodies.

[0003] The half-life of IgG in serum is extended relative to that of other plasma proteins, in part due to the binding of the Fc region of IgG to the Fc receptor FcRn. FcRn binds to IgG and protects IgG from transport to degradative lysosomes by recycling it back to the extracellular compartment. This recycling is facilitated by the pH-dependent binding of IgG to FcRn, with the IgG / FcRn interaction being stronger at acidic endosomal pH than at extracellular physiological pH.

[0004] When the serum concentration of IgG reaches a level that exceeds the available FcRn molecules, the unbound IgG is not protected from lysosomal degradation and will therefore have a shortened serum half-life. Therefore, inhibiting the binding of IgG to FcRn will shorten the serum half-life of IgG by preventing endosomal recycling of IgG. Agents that antagonize the binding of IgG to FcRn, such as FcRn binding molecules, can be used to regulate, treat or prevent antibody-mediated disorders, such as autoimmune diseases or inflammatory diseases.

[0005] Efgartigimod is a modified human immunoglobulin (Ig) γ (IgG) 1 derived za allotype Fc that binds to human FcRn with nanomolar affinity. Efgartigimod contains an IgG1 Fc region and has been engineered using ABDEG technology to increase its affinity for FcRn at both physiological and acidic pH. Efgartigimod's increased affinity for FcRn at both acidic and physiological pH results in blocking of FcRn-mediated IgG recycling. In the United States and Japan, Efgartigimod has been approved as a weekly intravenous injection for the treatment of systemic myasthenia gravis, and is being developed for the treatment of several other antibody-mediated diseases.

[0006] FcRn also binds and recycles serum albumin, which is a regulator of serum cholesterol levels. Advantageously, igamod does not have an effect on serum albumin levels in human subjects. However, it has recently been shown that anti-FcRn antibodies can cause a decrease in serum albumin levels and a concomitant increase in serum cholesterol levels in human subjects, both of which are undesirable.

[0007] Therefore, there is a need in the art for improved agents that antagonize FcRn binding to IgG with longer half-life, lower dosage, less frequent administration, better maintenance of albumin levels and / or reduced or eliminated FcRn degradation for the treatment of antibody-mediated disorders. Summary of the invention

[0008] The present disclosure broadly relates to neonatal Fc receptor (FcRn) binding molecules linked to a moiety that does not specifically bind to a human antigen and methods of use thereof. It is shown for the first time in the present application that, unexpectedly, the inclusion of a single non-human antigen binding moiety increases the stability and FcRn occupancy of the FcRn binding molecule.

[0009] On the one hand, there is provided herein an FcRn binding molecule connected to a portion that does not specifically bind to a human antigen, wherein the molecular weight of the FcRn binding molecule connected to the portion is between about 50 and about 140 kilodaltons (kDa). In some embodiments, the FcRn binding molecule is an FcRn antagonist. In some embodiments, the FcRn binding molecule is a variant Fc region that binds FcRn with increased affinity and reduced pH dependency relative to the wild-type Fc region. In some embodiments, the portion is not polyethylene glycol. In some embodiments, the portion is a polypeptide, optionally an antigen binding domain that does not specifically bind to a human antigen. In some embodiments, the molecule that does not specifically bind to a human antigen is an antigen binding domain that specifically binds to a non-human antigen.

[0010] In some embodiments, an FcRn / antigen binding molecule is provided, comprising an FcRn binding molecule and only one antigen binding domain connected to the FcRn binding molecule. In some embodiments, the antigen binding domain specifically binds to a non-human antigen.

[0011] In some embodiments, the pharmacodynamics and / or pharmacokinetics of the FcRn binding molecule are improved compared to igamod.

[0012] In some embodiments, the FcRn / antigen binding molecules have a molecular weight between 50 and 140 kilodaltons (kDa). In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of about 60kDa to about 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of 60kDa to 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of about 60kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of about 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of 60kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of 104kDa.

[0013] In some embodiments, the FcRn binding molecule is a variant Fc region, wherein the variant Fc region comprises a first Fc domain and a second Fc domain that form a dimer, wherein at least one of the Fc domains comprises amino acids Y, T, E, K, and F located at EU positions 252, 254, 256, 433, and 434, respectively.

[0014] In some embodiments, the variant Fc region consists of a first Fc domain and a second Fc domain that form a dimer.

[0015] In some embodiments, administration of a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule to a subject results in a decrease in serum IgG in the subject. In some embodiments, administration of a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule to a subject results in a decrease in serum IgG in the subject by at least about 35%, about 40%, about 50%, about 55%, or about 60% compared to the baseline level of serum IgG in the subject.

[0016] In some embodiments, administering a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule to a subject does not reduce FcRn and / or albumin levels in the subject.

[0017] In some embodiments, following a single administration of a therapeutically effective amount of the FcRn / antigen binding molecule or the FcRn binding molecule to the subject, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is less than about 2, about 1.9, about 1.8, about 1.7, about 1.6, about 1.5, about 1.4, about 1.3, about 1.2, about 1.1, about 1, about 0.9, about 0.8, about 0.7, about 0.6, or about 0.5 mL / h / kg.

[0018] In some embodiments, after a single administration of a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule to a subject, the half-life (t 1 / 2 ) is greater than about 30 hours, about 35 hours, about 40 hours, about 45 hours, about 50 hours, about 55 hours, about 60 hours, about 65 hours, about 70 hours, about 75 hours, about 80 hours, about 85 hours, about 90 hours, about 95 hours or about 100 hours.

[0019] In some embodiments, the FcRn / antigen binding molecule or FcRn binding molecule binds to FcRn at pH 5.5 and / or at pH 6.0 with a higher affinity than the affinity of igamod for FcRn at pH 5.5 and / or at pH 6.0, optionally as measured by surface plasmon resonance.

[0020] In some embodiments, the FcRn / antigen binding molecule or FcRn binding molecule binds to FcRn at pH 5.5 and / or at pH 6.0 with an affinity that is lower than the affinity of igamod for FcRn at pH 5.5 and / or at pH 6.0, optionally as measured by surface plasmon resonance.

[0021] In some embodiments, the antigen binding domain is selected from the group consisting of a Fab domain, an sdAb, a scFv, and an antibody mimetic. In some embodiments, the antibody mimetic is an anticalin or a DARPin. In some embodiments, the sdAb is a VHH fragment.

[0022] In some embodiments, the non-human antigen is a non-human antigen that can be found in the human body. In some embodiments, the non-human antigen that can be found in the human body is a viral antigen.

[0023] In some embodiments, the non-human antigen is a non-human antigen not found in the human body. In some embodiments, the non-human antigen not found in the human body is selected from hen egg lysozyme (HEL) or ovalbumin. In some embodiments, the non-human antigen not found in the human body is HEL, and the antigen binding domain is a Fab fragment or scFv comprising the HCDR1, HCDR2 and HCDR3 amino acid sequences of VH and LCDR1, LCDR2 and LCDR3 amino acid sequences of VL, the VH comprising the amino acid sequence of SEQ ID NO: 25, and the VL comprising the amino acid sequence of SEQ ID NO: 24.

[0024] In some embodiments, the non-human antigen not found in humans is HEL, and the antigen binding domain is a Fab or scFv domain comprising VH and VL, wherein the VH and VL domains comprise CDR sequences selected from the group consisting of: HCDR1 (SEQ ID NO: 18), HCDR2 (SEQ ID NO: 19), HCDR3 (SEQ ID NO: 20), LCDR1 (SEQ ID NO: 21), LCDR2 (SEQ ID NO: 22), and LCDR3 (SEQ ID NO: 23).

[0025] In some embodiments, VH comprises or consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:25, and VL comprises or consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:24.

[0026] In some embodiments, VH comprises or consists of the amino acid sequence of SEQ ID NO:25, and VL comprises or consists of the amino acid sequence of SEQ ID NO:24.

[0027] In some embodiments, the antigen binding domain is fused to the C-terminus of the first Fc domain or the second Fc domain. In some embodiments, the N-terminus of the antigen binding domain is fused to the C-terminus of the first Fc domain. In some embodiments, the N-terminus of the antigen binding domain is fused to the C-terminus of the second Fc domain.

[0028] In some embodiments, the antigen binding domain is fused to the N-terminus of the first Fc domain or the second Fc domain. In some embodiments, the N-terminus of the first Fc domain is fused to the C-terminus of the antigen binding domain. In some embodiments, the N-terminus of the second Fc domain is fused to the C-terminus of the antigen binding domain.

[0029] In some embodiments, the first Fc domain and / or the second Fc domain is an IgG Fc domain, such as an IgG1 Fc domain. In some embodiments, the first Fc domain and / or the second Fc domain is a human IgG Fc domain, such as a human IgG1 Fc domain.

[0030] In some embodiments, the variant Fc region comprises or consists of a first Fc domain and a second Fc domain that form a dimer, wherein the first Fc domain and / or the second Fc domain comprises amino acids Y, T, E, K, and F located at EU positions 252, 254, 256, 433, and 434, respectively. In some embodiments, the first Fc domain and / or the second Fc domain comprises amino acids Y, T, E, K, F, and Y located at EU positions 252, 254, 256, 433, 434, and 436, respectively.

[0031] In some embodiments, both the first and second Fc domain comprise amino acids Y, T, E, K, and F at EU positions 252, 254, 256, 433, and 434, respectively. In some embodiments, both the first and second Fc domain comprise amino acids Y, T, E, K, F, and Y at EU positions 252, 254, 256, 433, 434, and 436, respectively.

[0032] In some embodiments, both the first Fc domain and the second Fc domain are IgG Fc domains, such as human IgG Fc domains. In some embodiments, both the first Fc domain and the second Fc domain are IgG1 Fc domains, such as human IgG1 Fc domains.

[0033] In some embodiments, the antigen binding domain is fused to the first Fc domain or the second Fc domain via a linker. In some embodiments, the linker is a non-cleavable linker. In some embodiments, the linker is a peptide linker. In some embodiments, the peptide linker is a GS linker, optionally 8 to 40 amino acids in length, optionally 20 or 30 amino acids in length.

[0034] In some embodiments, the antigen binding domain is fused to the first Fc domain or the second Fc domain via an IgG hinge region or a portion thereof.

[0035] In some embodiments, the first Fc domain and / or the second Fc domain comprises an amino acid sequence independently selected from the group consisting of the amino acid sequences shown in SEQ ID NOs: 1, 2, and 3. In some embodiments, the first Fc domain and / or the second Fc domain comprises the amino acid sequence of SEQ ID NO:2.

[0036] In some embodiments, both the first Fc domain and the second Fc domain comprise an amino acid sequence independently selected from the group consisting of the amino acid sequences set forth in SEQ ID NOs: 1, 2, and 3. In some embodiments, both the first Fc domain and the second Fc domain comprise the amino acid sequence of SEQ ID NO:2.

[0037] In some embodiments, the amino acid sequence of each of the first Fc domain and the second Fc domain consists of an amino acid sequence independently selected from the group consisting of the amino acid sequences shown in SEQ ID NOs: 1, 2, and 3. In some embodiments, the amino acid sequence of the first Fc domain or the amino acid sequence of the second Fc domain consists of SEQ ID NO: 2.

[0038] In some embodiments, the amino acid sequence of both the first Fc domain and the second Fc domain consists of SEQ ID NO:2.

[0039] In some embodiments, the variant Fc region comprises one or more mutations of amino acid residues that form the interface of the CH3 domain of the Fc domain. In some embodiments, the variant Fc region comprises a knob-hole mutation.

[0040] In some embodiments, the amino acid sequence of the first Fc domain further comprises amino acid W at EU position 366.

[0041] In some embodiments, the amino acid sequence of the first Fc domain comprises an amino acid sequence selected from the group consisting of the amino acid sequences shown in SEQ ID NOs: 4, 5, and 6. In some embodiments, the amino acid sequence of the first Fc domain comprises the amino acid sequence of SEQ ID NO:5.

[0042] In some embodiments, the amino acid sequence of the first Fc domain consists of an amino acid sequence selected from the group consisting of the amino acid sequences set forth in SEQ ID NOs: 4, 5, and 6. In some embodiments, the amino acid sequence of the first Fc domain consists of the amino acid sequence of SEQ ID NO:5.

[0043] In some embodiments, the amino acid sequence of the second Fc domain further comprises amino acids S, A, and V at EU positions 366, 368, and 407, respectively.

[0044] In some embodiments, the amino acid sequence of the second Fc domain comprises an amino acid sequence selected from the group consisting of the amino acid sequences set forth in SEQ ID NOs: 7, 8, and 9. In some embodiments, the amino acid sequence of the second Fc domain comprises the amino acid sequence of SEQ ID NO:8.

[0045] In some embodiments, the amino acid sequence of the second Fc domain consists of an amino acid sequence selected from the group consisting of the amino acid sequences set forth in SEQ ID NOs: 7, 8, and 9. In some embodiments, the amino acid sequence of the second Fc domain consists of the amino acid sequence of SEQ ID NO:8.

[0046] On the one hand, there is provided herein an FcRn / antigen binding molecule comprising a first heavy chain, wherein the first heavy chain comprises an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:34. In some embodiments, the first heavy chain comprises or consists of an amino acid sequence of SEQ ID NO:34. In some embodiments, the FcRn / antigen binding molecule further comprises a second heavy chain, wherein the second heavy chain consists of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:8. In some embodiments, the second heavy chain consists of an amino acid sequence of SEQ ID NO:8.

[0047] In some embodiments, the FcRn / antigen binding molecule further comprises a light chain, wherein the light chain comprises or consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 24. In some embodiments, the light chain comprises or consists of the amino acid sequence of SEQ ID NO: 24.

[0048] Also provided are one or more isolated polynucleotides encoding any of the FcRn / antigen binding molecules described herein, or any of the antigen binding domains described herein, or any of the FcRn binding molecules described herein.

[0049] Also provided is an expression vector comprising any one or more of the isolated polynucleotides described herein.

[0050] Also provided is a host cell comprising any one or more of the isolated polynucleotides or any of the expression vectors described herein.

[0051] Also provided is a method for producing an FcRn / antigen binding molecule or an antigen binding domain or an FcRn binding molecule, the method comprising culturing a host cell as described herein under conditions allowing expression of the FcRn / antigen binding molecule or the antigen binding domain or the FcRn binding molecule.

[0052] Also provided is a pharmaceutical composition comprising an FcRn / antigen binding molecule as described herein, or an antigen binding domain as described herein, or an FcRn binding molecule as described herein and at least one pharmaceutically acceptable carrier.

[0053] Also provided is an FcRn / antigen binding molecule as described herein, or an antigen binding domain as described herein, or an FcRn binding molecule as described herein, or a pharmaceutical composition thereof, for use as a medicament.

[0054] Also provided is a method for reducing serum IgG in a subject, the method comprising administering to a subject in need thereof a therapeutically effective amount of an FcRn / antigen binding molecule as described herein, or an antigen binding domain as described herein, or an FcRn binding molecule as described herein, or a pharmaceutical composition thereof.

[0055] Also provided is a method of treating an antibody-mediated disorder in a subject, wherein the method comprises administering to a subject in need thereof a therapeutically effective amount of an FcRn / antigen binding molecule as described herein, or an antigen binding domain as described herein, or an FcRn binding molecule as described herein, or a pharmaceutical composition thereof.

[0056] In some embodiments, the antibody-mediated disorder is an IgG-mediated disorder. In some embodiments, the antibody-mediated disorder is an autoimmune disease.In some embodiments, the autoimmune disease is selected from the group consisting of: allogeneic islet transplant rejection, alopecia areata, ankylosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, Alzheimer's disease, anti-neutrophil cytoplasmic autoantibodies (ANCA), adrenal autoimmune disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune myocarditis, autoimmune neutropenia, autoimmune oophoritis and orchitis, immune thrombocytopenia (ITP or idiopathic thrombocytopenic purpura, idiopathic thrombocytopenic purpura, immune-mediated thrombocytopenia or primary immune thrombocytopenia), autoimmune urticaria, Behcet's disease, bullous Pemphigus (BP), cardiomyopathy, Castleman's disease, celiac sprue, chronic fatigue immune dysfunction syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), Chargar-Strauss syndrome, cicatricial pemphigoid, CREST syndrome, cold agglutinin disease, Crohn's disease, dilated cardiomyopathy, discoid lupus, epidermolysis bullosa acquisita, essential mixed cryoglobulinemia, factor VIII deficiency, fibromyalgia-fibromyositis, glomerulonephritis, Graves' disease, Guillain-Barré syndrome, Goodpasture's syndrome, graft-versus-host disease (GVHD), Hashimoto's thyroiditis, hemophilia A, idiopathic inflammatory myopathy (IIM), idiopathic membranous neuropathy, idiopathic Pulmonary fibrosis, IgA neuropathy, IgM polyneuropathy, immune-mediated necrotizing myopathy (IMNM), juvenile arthritis, Kawasaki disease, lichen planus, atrophic lichen sclerosus, lupus erythematosus, lupus nephritis, Meniere's disease, mixed connective tissue disease, mucous membrane pemphigoid, multiple sclerosis, type 1 diabetes, multifocal motor neuropathy (MMN), myasthenia gravis (MG), generalized myasthenia gravis (gMG), myositis, paraneoplastic bullous pemphigoid, pemphigoid gestationis, pemphigus vulgaris (PV), pemphigus foliaceus (PF), pernicious anemia, polyarteritis nodosa, polychondritis, polyglandular syndrome, polymyalgia rheumatica, polymyositis, dermatomyositis (DM), Necrotizing autoimmune myopathy (NAM), antisynthetase syndrome (ASyS), primary agammaglobulinemia, primary biliary cirrhosis, psoriasis, psoriatic arthritis, relapsing polychondritis, Raynaud's phenomenon, Reiter's syndrome, rheumatoid arthritis, sarcoidosis, scleroderma, Sjögren's syndrome, solid organ transplant rejection, stiff-person syndrome, systemic lupus erythematosus, Takayasu's arteritis, toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), temporal arteritis / giant cell arteritis, thrombotic thrombocytopenic purpura, ulcerative colitis, uveitis, dermatitis herpetiformis, vasculitis, antineutrophil cytoplasmic antibody-associated vasculitis, vitiligo, and Wegener's granulomatosis.

[0057] In some embodiments, the FcRn / antigen binding molecule or antigen binding domain or FcRn binding molecule and the additional therapeutic agent are administered to a subject simultaneously or sequentially.

[0058] Also provided is an FcRn / antigen binding molecule as described herein, or an antigen binding domain as described herein, or an FcRn binding molecule as described herein for use in treating an antibody-mediated disorder.

[0059] Also provided is the use of an FcRn / antigen binding molecule as described herein, or an antigen binding domain as described herein, or an FcRn binding molecule as described herein for the manufacture of a medicament for treating an antibody-mediated disorder. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figures 1A to 1B Figure 2 shows the in vitro FcRn occupancy of U937 cells after incubation with mAb37-ABDEG (full-length antibody), mAb37-OA-ABDEG (single-armed NT-mAb37 Fab fragment attached to Fc-ABDEG via the native hinge region), and ARGX-113. Figure 1A ) and FcRn degradation ( Figure 1B ).

[0061] Figure 2 Pharmacokinetic profiles of cynomolgus monkeys treated with an intravenous dose of OA-HEL-ABDEG (a one-armed molecule containing a Fab fragment attached to Fc-ABDEG at the N-terminus via the native hinge region) are shown. Monkeys (n=3 per group) received one of three doses: Group 1 - 10 mg / kg; Group 2 - 20 mg / kg; Group 3 - 85 mg / kg. OA-HEL-ABDEG serum concentration values ​​are plotted over time. Data points show mean ± SD. The mean concentrations on days 21 and 28 are based on observations of n=1. DETAILED DESCRIPTION

[0062] The present disclosure provides engineered FcRn binding molecules connected to portions that do not specifically bind to human antigens. On the one hand, FcRn binding molecules are connected to an antigen binding domain (FcRn / antigen binding molecules). In certain embodiments, a kind of FcRn / antigen binding molecules is provided, which is included in the C-terminus or at the N-terminus or at a position other than the C-terminus or the N-terminus and is connected to the FcRn binding molecules of the antigen binding domain. In certain embodiments, the antigen binding domain specifically binds to non-human antigens. Also provided herein are nucleic acids, vectors, host cells, manufacturing methods, and methods for their use in treating antibody-mediated diseases encoding such FcRn binding molecules or FcRn / antigen binding molecules.

[0063] definition

[0064] As used herein, the term "FcRn" refers to the neonatal Fc receptor. Exemplary FcRn molecules include human FcRn encoded by the FCGRT gene as shown in RefSeq NM 004107. The amino acid sequence of the corresponding protein is shown in RefSeq NP_004098.

[0065] As used herein, the term "FcRn binding molecule" refers to any agent that specifically binds to FcRn. As used herein, the term "FcRn antagonist" refers to any agent that specifically binds to FcRn and inhibits the binding of immunoglobulins to FcRn (e.g., human FcRn). In one embodiment, the FcRn antagonist comprises an Fc region (e.g., a variant Fc region disclosed herein) that specifically binds to FcRn and inhibits the binding of immunoglobulins to FcRn through the Fc region. In one embodiment, the FcRn antagonist is not a full-length IgG antibody. In one embodiment, the FcRn antagonist comprises an antigen binding domain and a variant Fc region that binds to a target antigen. In one embodiment, the term "FcRn antagonist" refers to an antibody or antigen binding fragment thereof that specifically binds to FcRn and inhibits the binding of the Fc region of an immunoglobulin (e.g., an IgG autoantibody) to FcRn. As used herein, the term "FcRn / antigen binding molecule" refers to any agent that specifically binds to FcRn and specifically binds to another antigen (which is not a human antigen). In some embodiments, the antigen is HEL. As used herein, the term "affinity" or "binding affinity" refers to the strength of the binding interaction between two molecules. As used herein, the term "equilibrium dissociation constant" or "K D " refers to the tendency of a two-molecule binding complex to dissociate into two free molecules. Therefore, as the binding affinity increases, K D reduce.

[0066] As used herein, the term "specific binding" refers to the ability of any molecule to preferentially bind to a given target. For example, a molecule that specifically binds to a given target may bind to other molecules, usually with lower affinity, as determined by, for example, immunoassays, BIAcore TM , KinExA 3000 instrument (Sapidyne Instruments, Boise, supra) or other assays known in the art. In a specific embodiment, a molecule that specifically binds to a given target has a K greater than that when the molecule non-specifically binds to another target. D K of at least 2 logs, 2.5 logs, 3 logs, 4 logs or less D Binds to antigen.

[0067] As used herein, the term "operably linked" refers to polynucleotide sequence elements being linked in a functional relationship. For example, when a polynucleotide sequence is in a functional relationship with another polynucleotide sequence, the polynucleotide sequence is operably linked. In some embodiments, if a transcriptional regulatory polynucleotide sequence (e.g., a promoter, enhancer, or other expression control element) affects the transcription of a polynucleotide sequence encoding a protein, the transcriptional regulatory polynucleotide sequence is operably linked to a polynucleotide sequence encoding the protein. Operably linked elements may be continuous or non-continuous.

[0068] As used herein, the term "connected" refers to a physical connection (e.g., direct or indirect connection) between amino acid sequences (e.g., different segments, regions, fragments or domains). The connected regions, fragments, domains and segments of the FcRn / antigen binding molecules of the present disclosure can be continuous or non-continuous (e.g., connected to each other through a linker). In some embodiments, the connection is covalent. In some embodiments, the connection is non-covalent.

[0069] As used herein, the term "covalently linked" refers to the connection of two molecules or chemical moieties by a covalent bond. In some embodiments, the covalent bond is a peptide bond or a disulfide bond. As used herein, the term "fusion" refers to the connection of two peptides by a peptide bond or a peptide linker. In some embodiments, two proteins are directly and continuously fused together by a peptide bond. In some embodiments, two proteins are indirectly and non-continuously fused by a peptide linker. In some embodiments, a protein is fused to a peptide linker by a peptide bond at a first position, and a second protein is fused to a peptide linker by a peptide bond at a second position. As used herein, the term "non-covalently linked" refers to the connection of two molecules or chemical moieties by a non-covalent interaction or bond. In some embodiments, non-covalent interactions or bonds include hydrogen bonds, electrostatic bonds or interactions, halogen bonds, π stacking, and van der Waals interactions.

[0070] The determination of "percent identity" between two sequences (e.g., amino acid sequences or nucleic acid sequences) can be accomplished using a mathematical algorithm. A specific, non-limiting example of a mathematical algorithm for comparing two sequences is the algorithm of Karlin S and Altschul SF, (1990) PNAS 87:2264-2268, as modified in Karlin S and Altschul SF, (1993) PNAS 90:5873-5877, each of which is incorporated herein by reference in its entirety. Such algorithms are incorporated into the NBLAST and XBLAST programs of Altschul SF et al., (1990) J Mol Biol 215:403, which is incorporated herein by reference in its entirety. BLAST nucleotide searches can be performed with the NBLAST nucleotide program parameter set (e.g., with score = 100, word length = 12) to obtain nucleotide sequences homologous to the nucleic acid molecules described herein. BLAST protein searches can be performed with the XBLAST program parameter set (e.g., with score = 50, word length = 3) to obtain amino acid sequences homologous to protein molecules described herein. In order to obtain gap alignments for comparison purposes, gap BLAST as described in Altschul SF et al., (1997) Nuc Acids Res 25:3389-3402 can be utilized, which is incorporated herein by reference in its entirety. Alternatively, PSI BLAST can be used to perform an iterative search for distance relationships between detection molecules. Same as above. When utilizing BLAST, gap BLAST, and PSI BLAST programs, the default parameters of the corresponding programs (e.g., XBLAST and NBLAST) can be used (see, e.g., the National Center for Biotechnology Information (NCBI) on the World Wide Web, ncbi.nlm.nih.gov). Another specific, non-limiting example of a mathematical algorithm for sequence comparison is the algorithm of Myers and Miller, (1988) CABIOS 4:11-17, which is incorporated herein by reference in its entirety. This algorithm is incorporated into the ALIGN program (version 2.0), which is part of the GCG sequence alignment software package.When utilizing the ALIGN program to compare amino acid sequences, a PAM120 weight residue table, a gap length penalty of 12, and a gap penalty of 4 may be used.

[0071] The percent identity between two sequences can be determined using techniques similar to those described above, with or without allowing gaps. In calculating the percent identity, typically only exact matches are counted.

[0072] As used herein, the term "antibody" or "antibodies" includes full-length antibodies, antigen-binding fragments of full-length antibodies, and molecules comprising antibody CDRs, VH domains (VH) or VL domains (VL). Examples of antibodies include monoclonal antibodies, recombinantly produced antibodies, monospecific antibodies, multispecific antibodies (including bispecific antibodies), human antibodies, humanized antibodies, chimeric antibodies, immunoglobulins, synthetic antibodies, tetrameric antibodies comprising two heavy chain and two light chain molecules, antibody light chain monomers, antibody heavy chain monomers, antibody light chain dimers, antibody heavy chain dimers, antibody light chain-antibody heavy chain pairs, intrabodies, heteroconjugate antibodies, antibody drug conjugates, single domain antibodies (sdAbs), monovalent antibodies, single chain antibodies or single chain Fv (scFv), camelid antibodies, humanized antibodies, affibody molecules, VHH fragments, Fab fragments, F(ab')2 fragments, disulfide-linked Fv (sdFv), anti-idiotypic (anti-Id) antibodies (including, e.g., anti-anti-Id antibodies), and antigen-binding fragments of any of the foregoing. The antibody can be of any isotype (e.g., IgG, IgE, IgM, IgD, IgA, or IgY), subclass (e.g., IgG1, IgG2, IgG3, IgG4, IgA1, or IgA2), or species (e.g., mouse IgG 2a or IgG 2b ).

[0073] As used herein, the term "antigen-binding domain" (or "antigen binding domain") refers to any polypeptide that specifically binds to an antigen. Examples of antigen-binding domains include polypeptides derived from antibodies, such as Fab fragments, F(ab')2 fragments, disulfide-linked Fvs (sdFv), single-chain Fvs (scFv), CDRs, VH domains (VH), VL domains (VL), single-domain antibodies (sdAb), VHH fragments, camelid antibodies, and antigen-binding fragments of any of the above. The term also encompasses synthetic antigen-binding proteins or antibody-mimicking proteins, such as, for example, anticalins and DARPins.

[0074] In some embodiments, the antigen binding domain is a VHH fragment. In some embodiments, the VHH fragment has one or more additional amino acids at its C-terminus. In some embodiments, the one or more additional amino acids are selected from the group consisting of: A, AG, GG, and PP.

[0075] As used herein, the term "Fc region" refers to the portion of an immunoglobulin formed by the Fc domains of its two heavy chains. The Fc region may be a wild-type Fc region (native Fc region) or a variant Fc region. The native Fc region is a homodimer. The Fc region may be derived from any natural immunoglobulin. In some embodiments, the Fc region is formed by IgA, IgD, IgE or IgG heavy chain constant regions. In some embodiments, the Fc region is formed by IgG heavy chain constant regions. In some embodiments, the IgG heavy chain is an IgG1, IgG2, IgG3 or IgG4 heavy chain constant region. In some embodiments, the Fc region is formed by an IgG1 heavy chain constant region. In some embodiments, the IgG1 heavy chain constant region comprises G1m1 (a), G1m2 (x), G1m3 (f) or G1m17 (z) allotypes. See, e.g., Jefferis and Lefranc (2009) mAbs 1(4):332-338, and de Taeye et al., (2020) Front Immunol. 11:740, which are incorporated herein by reference in their entireties.

[0076] As used herein, the term "variant Fc region" refers to a variant of an Fc region having one or more changes relative to a native Fc region. The changes may include amino acid substitutions, additions and / or deletions, attachment of additional moieties, and / or changes in native glycans. The term encompasses heterodimeric Fc regions in which each of the constituent Fc domains is different. The term also encompasses single-chain Fc regions in which the constituent Fc domains are linked together by a linker moiety.

[0077] As used herein, the term "Fc domain" refers to a portion of a single immunoglobulin heavy chain that includes both the CH2 domain and the CH3 domain of an antibody. In some embodiments, the Fc domain includes at least a portion of the hinge region (e.g., upper, middle and / or lower hinge region), the CH2 domain, and the CH3 domain. In some embodiments, the Fc domain does not include a hinge region.

[0078] As used herein, the term "hinge region" refers to the portion of the heavy chain molecule that joins the CH1 domain to the CH2 domain. In some embodiments, the hinge region is up to 70 amino acid residues in length. In some embodiments, the hinge region comprises about 11 to 17 amino acid residues and is flexible, thereby allowing two N-terminal antigen binding regions to move independently. In some embodiments, the hinge region is 12 amino acid residues in length. In some embodiments, the hinge region is 15 amino acid residues in length. In some embodiments, the hinge region is 62 amino acid residues in length. The hinge region can be subdivided into three different domains: upper, middle and lower hinge domains. The FcRn / antigen binding molecules of the present disclosure may include all or any portion of the hinge region. In some embodiments, the hinge region is from an IgG1 antibody. In some embodiments, the hinge region comprises the amino acid sequence of EPKSCDKTHTCPPCP (SEQ ID NO: 33).

[0079] As used herein, the term "FcRn-binding fragment" refers to a portion of an FcRn-binding molecule sufficient to confer FcRn binding, e.g., a portion of the Fc region.

[0080] As used herein, the term "one-armed / one armed", "one-arm / one arm" or "OA" refers to an FcRn / antigen binding molecule comprising an FcRn binding molecule connected to only one antigen binding domain. In some embodiments, "one-armed / one armed", "one-arm / one arm" or "OA" refers to an FcRn / antigen binding molecule comprising an Fc region comprising an Fc domain of two heavy chains, wherein one of the Fc domains of the two heavy chains is connected to the antigen binding domain, and the other Fc domain of the two heavy chains is not connected to the antigen binding domain. In some embodiments, the antigen binding domain is connected to the C-terminus of one of the Fc domains of the two heavy chains. In some embodiments, the antigen binding domain is connected to the N-terminus of one of the Fc domains of the two heavy chains. In some embodiments, the antigen binding domain is connected to a position other than the N-terminus or C-terminus of one of the Fc domains of the two heavy chains. The connection can be covalent or non-covalent. In some embodiments, the antigen binding domain is fused to the C-terminus of one of the Fc domains of the two heavy chains. In some embodiments, the antigen binding domain is fused to the N-terminus of one of the Fc domains of the two heavy chains. In some embodiments, the antigen binding domain is fused to a position other than the N-terminus or C-terminus of one of the Fc domains of the two heavy chains.

[0081] As used herein, the term "two-armed / two armed", "two-arm / two arm" or "TA" refers to an FcRn / antigen binding molecule comprising an FcRn binding molecule connected to two antigen binding domains. In some embodiments, "two-armed / two armed", "two-arm / two arm" or "TA" refers to an FcRn / antigen binding molecule comprising an Fc region comprising an Fc domain of two heavy chains, wherein each of the Fc domains of the two heavy chains is connected to an antigen binding domain. In some embodiments, the antigen binding domain is connected to the C-terminus of each of the Fc domains of the two heavy chains. In some embodiments, the antigen binding domain is connected to the N-terminus of each of the Fc domains of the two heavy chains. In some embodiments, the antigen binding domain is connected to a position other than the N-terminus or C-terminus of each of the Fc domains of the two heavy chains. In some embodiments, one of the antigen binding domains is connected to the N-terminus of one of the Fc domains of the two heavy chains, and the other antigen binding domain is connected to the C-terminus of the other Fc domain of the two heavy chains. In some embodiments, one of the antigen binding domains is connected to a position other than the N-terminus or C-terminus of one of the Fc domains of the two heavy chains, and the other antigen binding domain is connected to the N-terminus of the other Fc domain of the two heavy chains. In some embodiments, one of the antigen binding domains is connected to a position other than the N-terminus or C-terminus of one of the Fc domains of the two heavy chains, and the other antigen binding domain is connected to the C-terminus of the other Fc domain of the two heavy chains. The connection can be covalent or non-covalent. In some embodiments, the antigen binding domain is fused to the C-terminus of each of the Fc domains of the two heavy chains. In some embodiments, the antigen binding domain is fused to the N-terminus of each of the Fc domains of the two heavy chains. In some embodiments, the antigen binding domain is fused to a position other than the N-terminus or C-terminus of each of the Fc domains of the two heavy chains. In some embodiments, one of the antigen binding domains is fused to the N-terminus of one of the Fc domains of the two heavy chains, and the other antigen binding domain is fused to the C-terminus of the other Fc domain of the two heavy chains. In some embodiments, one of the antigen binding domains is fused to a position other than the N-terminus or C-terminus of one of the Fc domains of the two heavy chains, and the other antigen binding domain is fused to the N-terminus of the other Fc domain of the two heavy chains. In some embodiments, one of the antigen binding domains is fused to a position other than the N-terminus or C-terminus of one of the Fc domains of the two heavy chains, and the other antigen binding domain is fused to the C-terminus of the other Fc domain of the two heavy chains.

[0082] As used herein, the term "EU position" refers to the amino acid position of the Fc region according to the EU numbering convention as described in Edelman, GM et al. Proc. Natl. Acad. USA, 63, 78-85 (1969) and Rabat et al., "Sequences of Proteins of Immunological Interest," U. Sept. Health and Human Services, 5th Edition, 1991.

[0083] As used herein, the term "antibody-mediated disorder" refers to any disorder in which the symptoms of the disorder are caused by abnormal levels of one or more (self) antibodies in the subject. As used herein, the term "autoantibody-mediated disorder" refers to any disease or disorder in which the underlying pathology is caused at least in part by pathogenic IgG autoantibodies.

[0084] As used herein, the terms "treat", "treating", and "treatment" refer to therapeutic or preventive measures as described herein. The method of "treating" employs administering a polypeptide to a subject suffering from a disease or disorder or susceptible to such a disease or disorder to prevent, cure, delay, reduce the severity of, or ameliorate one or more symptoms of the disease or disorder or to prolong the survival of the subject beyond the expected survival in the absence of such treatment. In some embodiments, the method of "treating" employs administering a polypeptide to a subject suffering from a disease or disorder or susceptible to such a disease or disorder to prevent, cure, delay, reduce the severity of, or ameliorate the disease or disorder or recurring disease or disorder.

[0085] As used herein, the term "effective amount" in the context of administering a therapy to a subject refers to that amount of the therapy that achieves the desired prophylactic or therapeutic effect.

[0086] As used herein, the term "dose" or "administration" refers to the amount of a pharmaceutical agent administered to a subject in a single administration.

[0087] As used herein, the terms "fixed dose" or "uniform dose" both refer to a dose that does not vary based on the characteristics of the subject (e.g., weight, e.g., within a set range; sex; age, e.g., within a set range; etc.).

[0088] As used herein, the term "equivalent dose" refers to the dose of the first therapeutic agent and the second therapeutic agent, wherein the number of molecules of the first agent and the second agent is approximately the same. In some embodiments, the equivalent dose is an equimolar dose. As used herein, the term "equimolar dose" refers to the dose of the first therapeutic agent and the second therapeutic agent, wherein the number of moles of the first agent and the second agent is the same. In some embodiments, the first agent is an FcRn / antigen binding molecule and the second agent is Agamod. In some embodiments, the observed molecular weight of the first agent and the second agent is used to calculate the equivalent dose. In some embodiments, the predicted molecular weight of the first agent and the second agent is used to calculate the equivalent dose. In some embodiments, the observed molecular weight of the first agent and the predicted molecular weight of the second agent are used to calculate the equivalent dose. In some embodiments, the predicted molecular weight of the first agent and the observed molecular weight of the second agent are used to calculate the equivalent dose. In some embodiments, the predicted molecular weight of the first agent and the observed molecular weight of the second agent are used to calculate the equivalent dose.

[0089] As used herein, the terms "pharmacodynamics" and "PD" refer to the biological effect of a therapeutic agent on an organism. In some embodiments, the biological effect is the regulation of the amount of circulating IgG in an organism to which the therapeutic agent is administered. In some embodiments, the biological effect is the regulation of the amount of circulating albumin in an organism to which the therapeutic agent is administered. As used herein, the terms "improved pharmacodynamics" or "improved PD" refer to the improvement of a desired biological effect in an organism to which a therapeutic agent is administered. In some embodiments, the improved pharmacodynamics includes a reduction in the amount of circulating IgG in a subject. In some embodiments, the improved pharmacodynamics includes the maintenance of the amount of circulating albumin in a subject. In some embodiments, the improved pharmacodynamics includes a reduction in the amount of circulating IgG in a subject and the maintenance of the amount of circulating albumin in a subject. In some embodiments, the therapeutic agent is an FcRn / antigen binding molecule.

[0090] As used herein, the terms "pharmacokinetics" and "PK" refer to the effect of an organism on a therapeutic agent administered to the organism. In some embodiments, the effect is the metabolism and / or clearance of the therapeutic agent. In some embodiments, PK refers to the metabolic rate and / or clearance rate of the therapeutic agent. As used herein, the terms "improved pharmacokinetics" or "improved PK" refer to an improvement in an organism's desired effect on a therapeutic agent administered to the organism. In some embodiments, improved pharmacokinetics include an improvement in the half-life (T / V) of the therapeutic agent in a subject. 1 / 2 ), clearance rate or area under the curve (AUC). In some embodiments, the therapeutic agent is an FcRn / antigen binding molecule.

[0091] As used herein, the term "subject" or "patient" or "participant" includes any human or non-human animal. In one embodiment, the subject or patient or participant is a human or non-human mammal. In one embodiment, the subject or patient or participant is a human.

[0092] As used herein, when referring to a measurable value, such as a dosage, the term "about" or "approximately" encompasses variations of ±20%, ±15%, ±10%, ±5%, ±1%, or ±0.1% of a given value or range, as long as it is suitable for performing the methods disclosed herein.

[0093] As used herein, the term "molecular weight" may refer to a "predicted molecular weight" or an "observed molecular weight". The "predicted molecular weight" of a protein is the sum of the molecular weights of all the amino acids in the protein. In some cases, the "predicted molecular weight" of a molecule may differ from the "observed molecular weight". In some embodiments, these differences may occur in a protein due to changes in glycosylation, glycanation, ubiquitination, phosphorylation, or proteolytic cleavage of the protein or other proteins in complex with a given protein.

[0094] FcRn binding molecules

[0095] The FcRn binding molecules disclosed herein include any molecule that binds to FcRn, including but not limited to any anti-FcRn antibody, any anti-FcRn binding region, or any Fc domain or Fc region.

[0096] In some embodiments, the FcRn binding molecules disclosed herein are linked to a portion that does not specifically bind to a human antigen. In some embodiments, the portion that does not specifically bind to a human antigen increases the half-life of the FcRn binding molecule without inducing any biological effect of its own. In some embodiments, the portion does not specifically bind to an antigen. In some embodiments, the portion is a polypeptide. In some embodiments, the polypeptide has the structure of an antigen binding domain, but does not specifically bind to an antigen. In some embodiments, the polypeptide is an antigen binding domain that specifically binds to a non-human antigen. Non-exclusive examples of antigen binding domains that specifically bind to non-human antigens are provided herein.

[0097] In some embodiments, the FcRn binding molecule is an FcRn antagonist, which includes any molecule that binds to and inhibits FcRn, including but not limited to any anti-FcRn antibody, any anti-FcRn binding region, or any Fc domain or Fc region.

[0098] In some embodiments, the FcRn binding molecules disclosed herein comprise two, three, or four FcRn binding regions, such as Fc regions.

[0099] In some embodiments, the FcRn binding molecules disclosed herein comprise one or more Fc regions, or FcRn binding fragments thereof, in combination with one or more antigen binding domains (e.g., sdAb, Fab fragment, scFv, or antibody mimetic).

[0100] Any Fc region can be changed to produce a variant Fc region as disclosed herein. In general, the Fc region or its FcRn binding fragment is from a human immunoglobulin. However, it should be understood that the Fc region can be derived from the immunoglobulin of any other mammalian species, including, for example, camel species, rodents (e.g., mice, rats, rabbits, guinea pigs) or non-human primates (e.g., orangutans, macaques) species. In addition, the Fc region or its FcRn binding portion can be derived from any immunoglobulin class, including IgM, IgG, IgD, IgA and IgE, and any immunoglobulin isotype, including IgG1, IgG2, IgG3 and IgG4. In one embodiment, the Fc region is an IgG Fc region (e.g., human IgG region). In one embodiment, the Fc region is an IgG1 Fc region (e.g., human IgG1 region). In one embodiment, the Fc region is a chimeric Fc region comprising a portion of several different Fc regions. Suitable examples of chimeric Fc regions are described in US2011 / 0243966A1, which is incorporated herein by reference in its entirety.A variety of Fc region gene sequences (eg, human constant region gene sequences) are available in the form of publicly available deposits.

[0101] The Fc region may be further truncated or internally deleted to generate a minimal FcRn binding fragment thereof. The ability of the Fc region fragment to bind to FcRn may be determined using any art-recognized binding assay, such as ELISA.

[0102] In order to enhance the manufacturability of the FcRn binding molecules and FcRn / antigen binding molecules containing the same as disclosed herein, it is preferred that the constituent Fc regions do not contain any non-disulfide bonded cysteine ​​residues. Thus, in one embodiment, the Fc region does not contain free cysteine ​​residues.

[0103] In some embodiments, any Fc variant or its FcRn binding fragment that specifically binds to FcRn with increased affinity and reduced pH dependence relative to the native Fc region can be used herein. In one embodiment, the variant Fc region comprises amino acid changes, substitutions, insertions and / or deletions that confer desired characteristics. In some embodiments, the FcRn binding molecule comprises a variant Fc region or its FcRn binding fragment, which binds to FcRn with higher affinity at pH 5.5 compared to the corresponding wild-type Fc region. In some embodiments, the FcRn binding molecule comprises a variant Fc region or its FcRn binding fragment, which binds to FcRn with higher affinity at pH 6.0 and / or at pH 7.4 compared to the corresponding wild-type Fc region. In some embodiments, the FcRn binding molecule comprises a variant Fc region or its FcRn binding fragment, which binds to FcRn with higher affinity at both acidic and neutral pH compared to the corresponding wild-type Fc region.

[0104] In some embodiments, the variant Fc region is derived from the Fc region of any natural immunoglobulin. In some embodiments, the natural immunoglobulin is a human immunoglobulin. In some embodiments, the immunoglobulin is IgA, IgD, IgE or IgG. In some embodiments, the immunoglobulin is IgG. In some embodiments, the immunoglobulin is human IgA, human IgD, human IgE or human IgG. In some embodiments, the immunoglobulin is human IgG. In some embodiments, IgG is IgG1, IgG2, IgG3 or IgG4. In some embodiments, human IgG is human IgG1, human IgG2, human IgG3 or human IgG4. In some embodiments, the variant Fc region is different from the human IgG1 Fc region. In some embodiments, the human IgG1 Fc region comprises G1m1 (a), G1m2 (x), G1m3 (f) or G1m17 (z) allotypes.

[0105] In some embodiments, the FcRn binding molecule is an FcRn antagonist.

[0106] Other known Fc domain variants that can be used in the compositions disclosed herein include, but are not limited to, Ghetie et al., 1997, Nat. Biotech. 15:637-40; Duncan et al., 1988, Nature 332:563-564; Lund et al., 1991, J. Immunol, 147:2657-2662; Lund et al., 1992, Mol. Immunol, 29:53-59; Alegre et al., 1994, Transplantation 57:1537-1543; Hutchins et al., 1995, Proc Natl. Acad Sci USA, 92:11980-11984; Jefferis et al., 1995, Immunol Lett., 44: 111-117; Lund et al., 1995, Faseb J., 9: 115-119; Jefferis et al., 1996, Immunol Lett., 54: 101-104; Lund et al., 1996, J. Immunol, 157: 4963-4969; Armour et al., 1999, Eur J Immunol 29: 2613-2624; Idusogie et al., 2000, J. Immunol, 164: 4178-4184; Reddy et al., 2000, J. Immunol, 164: 1925-1933; Xu et al., 2000, Cell Immunol, 200: 16-26; Idusogie et al., 2001, J. Immunol, 166: 2571-2575; Shields et al., 2001, J Biol. Chem., 276: 6591-6604; Jefferis et al., 2002, Immunol Lett., 82: 57-65; Presta et al., 2002, Biochem Soc Trans., 30:487-490); U.S. Patent Nos. 5,624,821; 5,885,573; 5,677,425; 6,165,745; 6,277,375; 5,869,046; 6,121,022; 5,624,821; 5,648,260; 6,528,624; 6,194,551; 6,737,056; 6,821,505; 6,277,375; U.S. Patent Publication No. 2004 / 0002587 and PCT Publication Nos. WO 94 / 29351; WO 99 / 58572; WO 00 / 42072; WO 02 / 060919; WO 04 / 029207; WO 04 / 099249; WO 04 / 063351, the contents of which are incorporated by reference in their entirety.

[0107] In one embodiment, the variant Fc region or its FcRn binding fragment comprises or consists of two Fc domains. In one embodiment, the variant Fc region or its FcRn binding fragment comprises at least one Fc domain comprising amino acids Y, T, E, K and F located at EU positions 252, 254, 256, 433 and 434, respectively. In one embodiment, the variant Fc region or its FcRn binding fragment comprises at least one Fc domain comprising amino acids Y, T, E, K, F and Y located at EU positions 252, 254, 256, 433, 434 and 436, respectively. In one embodiment, the variant Fc region or its FcRn binding fragment consists of two Fc domains, both of which comprise amino acids Y, T, E, K and F located at EU positions 252, 254, 256, 433 and 434, respectively. In one embodiment, the variant Fc region or FcRn binding fragment thereof consists of two Fc domains, both of which comprise amino acids Y, T, E, K, F and Y at EU positions 252, 254, 256, 433, 434 and 436, respectively.

[0108] In one embodiment, the amino acid sequence of the Fc domain of the variant Fc region comprises the amino acid sequence of SEQ ID NO: 1. In one embodiment, the amino acid sequence of the Fc domain of the variant Fc region consists of the amino acid sequence of SEQ ID NO: 1. In one embodiment, the amino acid sequence of the Fc domain of the variant Fc region comprises the amino acid sequence of SEQ ID NO: 2. In one embodiment, the amino acid sequence of the Fc domain of the variant Fc region consists of the amino acid sequence of SEQ ID NO: 2. In one embodiment, the amino acid sequence of the Fc domain of the variant Fc region comprises the amino acid sequence of SEQ ID NO: 3. In one embodiment, the amino acid sequence of the Fc domain of the variant Fc region consists of the amino acid sequence of SEQ ID NO: 3.

[0109] In one embodiment, the FcRn binding molecule comprises a variant Fc region, wherein the variant Fc region comprises two Fc domains, wherein the amino acid sequence of each of the Fc domains is independently selected from SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3.

[0110] In certain embodiments, the variant Fc region is a heterodimer in which the constituent Fc domains are different from each other. Methods for producing Fc heterodimers are known in the art (see, e.g., US 8,216,805, which is incorporated herein by reference in its entirety). In one embodiment, the FcRn binding molecule is composed of a variant Fc region, wherein the variant Fc region is composed of two Fc domains forming a heterodimer, wherein the amino acid sequence of each of the Fc domains is independently selected from SEQ ID NO: 1, SEQ ID NO: 2 and SEQ ID NO: 3. In one embodiment, the FcRn binding molecule is composed of or comprises a variant Fc region, wherein the variant Fc region is composed of or comprises two Fc domains forming a heterodimer, wherein the amino acid sequence of the first Fc domain comprises or consists of the amino acid sequence of SEQ ID NO: 1, and the amino acid sequence of the second Fc domain comprises or consists of the amino acid sequence of SEQ ID NO: 2 or SEQ ID NO: 3. In one embodiment, the FcRn binding molecule consists of or comprises a variant Fc region, wherein the variant Fc region consists of or comprises two Fc domains forming a heterodimer, wherein the amino acid sequence of the first Fc domain comprises or consists of the amino acid sequence of SEQ ID NO: 2, and the amino acid sequence of the second Fc domain comprises or consists of the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 3. In one embodiment, the FcRn binding molecule consists of or comprises a variant Fc region, wherein the variant Fc region consists of or comprises two Fc domains forming a heterodimer, wherein the amino acid sequence of the first Fc domain comprises or consists of the amino acid sequence of SEQ ID NO: 3, and the amino acid sequence of the second Fc domain comprises or consists of the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2.

[0111] In one embodiment, the FcRn binding molecule comprises a variant Fc region, wherein the variant Fc region comprises or consists of two Fc domains forming a homodimer, wherein the amino acid sequence of each of the Fc domains comprises or consists of the amino acid sequence of SEQ ID NO: 1.

[0112] In one embodiment, the FcRn binding molecule comprises a variant Fc region, wherein the variant Fc region consists of or comprises two Fc domains forming a homodimer, wherein the amino acid sequence of each of the Fc domains comprises or consists of the amino acid sequence of SEQ ID NO: 2.

[0113] In one embodiment, the FcRn binding molecule comprises a variant Fc region, wherein the variant Fc region consists of or comprises two Fc domains forming a homodimer, wherein the amino acid sequence of each of the Fc domains comprises or consists of the amino acid sequence of SEQ ID NO: 3.

[0114] In one embodiment, the FcRn binding molecule comprises a variant Fc region, wherein the variant Fc region comprises or consists of Agamod (CAS Reg. No. 1821402-21-4). As used herein, the term "Agamod" is interchangeable with "Agamod α". In some embodiments, Agamod is Agamod α-fcab.

[0115] In one embodiment, the variant Fc region is modified to promote heterodimerization. Such modifications are known in the art, and any suitable method that promotes heterodimerization can be used to generate FcRn / antigen binding molecules described herein. In some embodiments, the variant Fc region comprises one or more mutations of amino acid residues at the interface of the CH3 domain forming the Fc domain. In some embodiments, the variant Fc region comprises a knob-hole structure mutation (see, e.g., Intl. Publ. WO2006 / 028936, which is incorporated by reference in its entirety). In this technology, the mispairing of Ig heavy chains is reduced by mutations to form the selected amino acids at the interface of the CH3 domain in IgG. At the position where the two heavy chains directly interact in the CH3 domain, one or more amino acids with a small side chain (hole) are introduced into the sequence of one heavy chain, and one or more amino acids with a large side chain (knob) are introduced into the corresponding interaction residue position on the other heavy chain. The Fc domain of the Fc region can be composed of immunoglobulin chains of the same subclass (eg, IgG1 or IgG3) or of different subclasses (eg, IgG1 and IgG3, or IgG3 and IgG4).

[0116] In some embodiments, the variant Fc region comprises or consists of two Fc domains, wherein one of the Fc domains comprises the amino acid W at EU position 366. In some embodiments, the variant Fc region comprises or consists of two Fc domains, wherein one of the Fc domains comprises the amino acids S, A, and V at EU positions 366, 368, and 407, respectively. In some embodiments, the variant Fc region comprises or consists of two Fc domains, wherein one of the Fc domains comprises the amino acid W at EU position 366 and the other Fc domain comprises the amino acids S, A, and V at EU positions 366, 368, and 407, respectively.

[0117] In some embodiments, the variant Fc region comprises or consists of two Fc domains, one of which comprises amino acids E and D at EU positions 370 and 409, respectively, and the other comprises amino acid K at EU positions 357 and 399. In some embodiments, the variant Fc region comprises or consists of two Fc domains, one of which comprises amino acids H and A at EU positions 364 and 405, respectively, and the other comprises amino acids T and F at EU positions 349 and 394, respectively. In some embodiments, the variant Fc region comprises or consists of two Fc domains, one of which comprises amino acids V, Y, A, and V at EU positions 350, 351, 405, and 407, respectively, and the other comprises amino acids V, L, L, and W at EU positions 350, 366, 392, and 394, respectively. In some embodiments, the variant Fc region comprises or consists of two Fc domains, one of which comprises amino acids D, M, and A at EU positions 360, 399, and 407, respectively, and the other comprises amino acids R, R, V, and V at EU positions 345, 347, 366, and 409, respectively. In some embodiments, the variant Fc region comprises or consists of two Fc domains, one of which comprises amino acids D at EU positions 409 and 392, and the other comprises amino acids K at EU positions 399 and 356. In some embodiments, the variant Fc region comprises or consists of two Fc domains, one of which comprises amino acids E, W, and C at EU positions 360, 409, and 349, respectively, and the other comprises amino acids R, V, T, and C at EU positions 347, 399, 405, and 354, respectively. In some embodiments, the variant Fc region comprises or consists of two Fc domains, wherein one Fc domain comprises amino acids E and W at EU positions 370 and 409, respectively, and the other Fc domain comprises amino acids N, V, and T at EU positions 357, 399, and 405, respectively.

[0118] In one embodiment, the FcRn binding molecule consists of a variant Fc region, wherein the variant Fc region comprises or consists of two Fc domains forming a heterodimer, wherein the amino acid sequence of the first Fc domain is selected from the group consisting of amino acid sequences comprising or consisting of SEQ ID NO: 4, SEQ ID NO: 5 and SEQ ID NO: 6, and / or the amino acid sequence of the second Fc domain is selected from the group consisting of amino acid sequences comprising or consisting of SEQ ID NO: 7, SEQ ID NO: 8 and SEQ ID NO: 9. In one embodiment, the FcRn binding molecule consists of a variant Fc region, wherein the variant Fc region comprises or consists of two Fc domains forming a heterodimer, wherein the amino acid sequence of the first Fc domain is selected from the group consisting of amino acid sequences comprising or consisting of SEQ ID NO: 7, SEQ ID NO: 8 and SEQ ID NO: 9, and / or the amino acid sequence of the second Fc domain is selected from the group consisting of amino acid sequences comprising or consisting of SEQ ID NO: 4, SEQ ID NO: 5 and SEQ ID NO: 6. In one embodiment, the FcRn binding molecule consists of a variant Fc region, wherein the variant Fc region comprises or consists of two Fc domains forming a heterodimer, wherein the amino acid sequence of the first Fc domain comprises or consists of SEQ ID NO: 4, and the amino acid sequence of the second Fc domain comprises or consists of SEQ ID NO: 7. In one embodiment, the FcRn binding molecule consists of a variant Fc region, wherein the variant Fc region comprises or consists of two Fc domains forming a heterodimer, wherein the amino acid sequence of the first Fc domain comprises or consists of SEQ ID NO: 5, and the amino acid sequence of the second Fc domain comprises or consists of SEQ ID NO: 8. In one embodiment, the FcRn binding molecule consists of a variant Fc region, wherein the variant Fc region comprises or consists of two Fc domains forming a heterodimer, wherein the amino acid sequence of the first Fc domain comprises or consists of SEQ ID NO: 6, and the amino acid sequence of the second Fc domain comprises or consists of SEQ ID NO: 9. In some embodiments, the FcRn binding molecule is an FcRn antagonist.

[0119] Table 1. Amino acid sequences of variant Fc regions

[0120]

[0121]

[0122] In some embodiments, the variant Fc region comprises a first Fc domain comprising amino acids Y, T, E, K, and F at EU positions 252, 254, 256, 433, and 434, respectively, and a second Fc domain comprising amino acids K and F at EU positions 433 and 434, respectively. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 1. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 2. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 3.

[0123] In some embodiments, the variant Fc region comprises a first Fc domain comprising amino acids Y, T, E, W, K and F at EU positions 252, 254, 256, 366, 433 and 434, respectively, and a second Fc domain comprising amino acids S, A, V, K and F at EU positions 366, 368, 407, 433 and 434, respectively. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 4. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 5. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 6.

[0124] In some embodiments, the variant Fc region comprises a first Fc domain comprising amino acids Y, T, E, S, A, V, K, and F at EU positions 252, 254, 256, 366, 368, 407, 433, and 434, respectively, and a second Fc domain comprising amino acids W, K, and F at EU positions 366, 433, and 434, respectively. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 7. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 8. In some embodiments, the first Fc domain comprises the amino acid sequence of SEQ ID NO: 9.

[0125] In one embodiment, the anti-FcRn antibody is rozanolimab (UCB7665), nicalizumab (M281), onorimumab (ALXN1830 / SYNT001), or bartolimumab (IMVT-1401 / RVT1401 / HBM9161).

[0126] In one embodiment, the antibody that specifically binds to FcRn and inhibits the binding of the Fc region of an immunoglobulin to FcRn is nipocalimab, also known as M281. Nipocalimab is a full-length "Fc dead" IgG1 monoclonal antibody. In Phase 2 / 3 clinical trials for the treatment of myasthenia gravis (MG) and warm autoimmune hemolytic anemia (WAIHA), and in Phase 2 clinical trials for the treatment of fetal and neonatal hemolytic disease (HDFN), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and Sjögren's syndrome (SS), nipocalimab has been administered as an intravenous infusion. Nipocalimab comprises the light chain (SEQ ID NO: 10) and heavy chain (SEQ ID NO: 11) sequences shown in Table 2 below (VL of SEQ ID NO: 10 and VH of SEQ ID NO: 11 are underlined):

[0127] Table 2. Heavy and light chain sequences of nikalimab

[0128]

[0129] In one embodiment, the antibody that specifically binds to FcRn and inhibits the binding of the Fc region of an immunoglobulin to FcRn is rozanolixizumab, also known as UCB 7665. Rozanolixizumab is a full-length humanized IgG4 monoclonal antibody. In clinical trials for MG, immune thrombocytopenia (ITP), chronic inflammatory demyelinating polyneuropathy (CIDP), autoimmune encephalitis (AIE), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOG-AD), rozanolixizumab has been administered as a subcutaneous infusion. Rozanolixizumab comprises the light chain (SEQ ID NO: 12) and heavy chain (SEQ ID NO: 13) sequences shown in Table 3 below (VL of SEQ ID NO: 12 and VH of SEQ ID NO: 13 are underlined):

[0130] Table 3. Heavy and light chain sequences of rozanolimumab

[0131]

[0132] In one embodiment, the antibody that specifically binds to FcRn and inhibits the binding of the Fc region of an immunoglobulin to FcRn is Onorimab, also known as SYNT001 / ALXN1830. Onorimab is another full-length humanized IgG4 monoclonal antibody. In Phase 2 clinical trials for the treatment of WAIHA and pemphigus, Onorimab has been administered as an intravenous infusion. Onorimab comprises the light chain (SEQ ID NO: 14) and heavy chain (SEQ ID NO: 15) sequences shown in Table 4 below (VL of SEQ ID NO: 14 and VH of SEQ ID NO: 15 are underlined):

[0133] Table 4. Heavy and light chain sequences of Onorimab

[0134]

[0135] In one embodiment, the antibody that specifically binds to FcRn and inhibits the binding of the Fc region of an immunoglobulin to FcRn is Bartolimab, also known as IMVT1401 / RVT1401 / HBM9161. Bartolimab is a full-length "Fc-invalid" IgG1 monoclonal antibody. In Phase 2 clinical trials for the treatment of MG, ITP, Graves' ophthalmopathy, thyroid eye disease, and neuromyelitis optica spectrum disorders (NMOSD), Bartolimab has been administered as a subcutaneous injection. Bartolimab comprises the light chain (SEQ ID NO: 16) and heavy chain (SEQ ID NO: 17) sequences shown in Table 5 below (VL of SEQ ID NO: 16 and VH of SEQ ID NO: 17 are underlined):

[0136] Table 5. Heavy and light chain sequences of Batolimumab

[0137]

[0138] FcRn / antigen binding molecules

[0139] In one aspect, the present disclosure provides FcRn / antigen binding molecules or fragments thereof. In some embodiments, the FcRn / antigen binding molecules disclosed herein comprise an FcRn binding molecule and only one antigen binding domain. The FcRn binding molecule can be any FcRn binding molecule described herein. Similarly, the antigen binding domain can be any antigen binding domain described herein.

[0140] In some embodiments, the antigen binding domain is connected to the C-terminus of the FcRn binding molecule. In some embodiments, the antigen binding domain is connected to the N-terminus of the FcRn binding molecule. In some embodiments, the antigen binding domain is connected to the FcRn binding molecule at a position other than the C-terminus or the N-terminus. The antigen binding domain can be covalently or non-covalently linked to the FcRn binding molecule.

[0141] In some embodiments, the antigen binding domain is fused to the C-terminus of the FcRn binding molecule. In some embodiments, the antigen binding domain is fused to the N-terminus of the FcRn binding molecule. In some embodiments, the antigen binding domain is fused to the FcRn binding molecule at a position other than the C-terminus or the N-terminus.

[0142] In some embodiments, the FcRn binding molecule is an Fc region, such as a variant Fc region. In some embodiments, the antigen binding domain is connected or fused to the C-terminus of one of the Fc domains of the variant Fc region. In some embodiments, the antigen binding domain is connected or fused to the N-terminus of one of the Fc domains of the variant Fc region. In some embodiments, the antigen binding domain is connected or fused to the FcRn binding molecule at a position other than the C-terminus or the N-terminus.

[0143] In some embodiments, the antigen binding domain can be directly connected or fused to the N-terminus or C-terminus of the FcRn binding molecule. In some embodiments, the antigen binding domain is connected to the N-terminus or C-terminus of the FcRn binding molecule via a linker. In some embodiments, the linker is a non-cleavable linker.

[0144] In some embodiments, the antigen binding domain can be directly connected (e.g., fused) to the N-terminus or C-terminus of the Fc domain. In some embodiments, the antigen binding domain is connected to the N-terminus or C-terminus of the Fc domain via a linker. The linker can be any suitable linker, including those described herein.

[0145] Antigen binding domain

[0146] In one aspect, the present disclosure provides antigen binding domains. In some embodiments, the FcRn / antigen binding molecules disclosed herein include one or more FcRn binding molecules combined with one or more antigen binding domains. In some embodiments, the FcRn / antigen binding molecules disclosed herein include one or more Fc regions or FcRn binding fragments thereof combined with one or more antigen binding domains. In some embodiments, the antigen binding domain is a polypeptide derived from an antibody, including but not limited to sdAb (e.g., VHH fragment), Fab fragment, scFv, VH or VL. In some embodiments, the antigen binding domain is a synthetic antigen binding protein or antibody mimetic protein, including but not limited to anticalin or DARPin.

[0147] In some embodiments, the antigen binding domain further comprises one or more amino acids added at its C-terminus. In some embodiments, the antigen binding domain further comprises one or more amino acids selected from A, AG, GG and PP added at the C-terminus.

[0148] Antigen binding domains can bind to any antigen. In some embodiments, antigens are non-human antigens, for example, proteins or fragments thereof that are not usually expressed by humans and are not usually found in the human body. In some embodiments, non-human antigens are proteins or fragments thereof that are not usually expressed by humans but can be found in the human body. Examples of non-human antigens that can be found in the human body include proteins or fragments thereof expressed by pathogens, such as bacterial or viral proteins or fragments thereof. Due to infection and / or immunity, these pathogenic proteins or fragments thereof can be found in the human body. Therefore, in some embodiments, the non-human antigens that can be found in the human body are viral antigens. In some embodiments, the virus is rabies virus. In some embodiments, the antigen binding domain that binds to rabies virus is a VHH fragment. In some embodiments, the VHH fragment that binds to rabies virus comprises the amino acid sequence (CDR underlined) of SEQ ID NO:29 shown in Table 6 below. In some embodiments, the VHH fragment that binds to rabies virus comprises a combination of CDR1, CDR2, and CDR3, wherein CDR1 is SSDMS (SEQ ID NO: 26), CDR2 is GINSGGGRTLYADSVKG (SEQ ID NO: 27), and CDR3 is SWYTDY (SEQ ID NO: 28).

[0149] Table 6.3 Rab VHH

[0150]

[0151] In some embodiments, the non-human antigen is a non-human antigen not found in humans. Examples of non-human antigens not found in humans include proteins or fragments thereof that are non-pathogenic and have no human counterparts, such as, for example, hen egg lysozyme (HEL) or ovalbumin.

[0152] In some embodiments, the antigen binding domain specifically binds to HEL. In some embodiments, the antigen binding domain specifically binds to HEL and is selected from a Fab fragment, a scFv, and a sdAb. In some embodiments, the antigen binding domain specifically binds to HEL and is a Fab fragment or a scFv.

[0153] In some embodiments, the antigen binding domain is a Fab fragment or scFv comprising the HCDR1, HCDR2, and HCDR3 amino acid sequence of VH and comprising the LCDR1, LCDR2, and LCDR3 amino acid sequence of VL, wherein VH comprises the amino acid sequence of SEQ ID NO:25 and VL comprises the amino acid sequence of SEQ ID NO:24.

[0154] In some embodiments, the antigen binding domain is a Fab fragment or scFv comprising a combination of VHCDR1, VHCDR2, VHCDR3, VLCDR1, VLCDR2, and VLCDR3, wherein 1, 2, 3, 4, or 5 amino acids are different in at least one of the amino acid sequences selected from SEQ ID NOs: 18, 19, 20, 21, 22, and 23. In some embodiments, the antigen binding domain is a Fab fragment or scFv comprising a combination of VHCDR1, VHCDR2, VHCDR3, VLCDR1, VLCDR2, and VLCDR3 selected from SEQ ID NOs: 18, 19, 20, 21, 22, and 23.

[0155] In some embodiments, the antigen binding domain is a Fab fragment or scFv consisting of a combination of VHCDR1, VHCDR2, VHCDR3, VLCDR1, VLCDR2, and VLCDR3, wherein 1, 2, 3, 4, or 5 amino acids are different in at least one of the amino acid sequences selected from SEQ ID NOs: 18, 19, 20, 21, 22, and 23. In some embodiments, the antigen binding domain is a Fab fragment or scFv consisting of a combination of VHCDR1, VHCDR2, VHCDR3, VLCDR1, VLCDR2, and VLCDR3 selected from SEQ ID NOs: 18, 19, 20, 21, 22, and 23.

[0156] In some embodiments, the antigen binding domain is a Fab fragment or scFv comprising VH and VL, wherein VH comprises an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 25, and VL comprises an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 24. In some embodiments, the antigen binding domain is a Fab fragment or scFv comprising VH and VL, wherein VH comprises the amino acid sequence of SEQ ID NO: 25, and wherein VL comprises the amino acid sequence of SEQ ID NO: 24.

[0157] In some embodiments, the antigen binding domain is a Fab fragment or scFv comprising VH and VL, wherein VH consists of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 25, and wherein VL consists of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to an amino acid sequence selected from SEQ ID NO: 24. In some embodiments, the antigen binding domain is a Fab fragment or scFv comprising VH and VL, wherein VH consists of the amino acid sequence of SEQ ID NO: 25, and wherein VL consists of the amino acid sequence of SEQ ID NO: 24.

[0158] In some embodiments, the antigen binding domain specifically binds to a rabies virus protein, such as an envelope protein of a rabies virus. In some embodiments, the rabies virus protein is a rabies G protein. In some embodiments, the antigen binding domain specifically binds to a rabies virus protein and is selected from a Fab fragment, scFv, and sdAb. In some embodiments, the antigen binding domain specifically binds to a rabies virus protein and is an sdAb, such as a VHH fragment.

[0159] In some embodiments, the antigen binding domain is a VHH fragment comprising the following: CDR1, CDR2 and CDR3 amino acid sequences of a VHH fragment comprising the amino acid sequence of SEQ ID NO:29.

[0160] In some embodiments, the antigen binding domain is a VHH fragment comprising a combination of CDR1, CDR2, and CDR3, wherein 1, 2, 3, 4, or 5 amino acids differ in at least one of the amino acid sequences selected from: SEQ ID NOs: 26, 27, and 28. In some embodiments, the antigen binding domain is a VHH fragment comprising a combination of CDR1, CDR2, and CDR3 selected from: SEQ ID NOs: 26, 27, and 28.

[0161] In some embodiments, the antigen binding domain is a VHH fragment consisting of a combination of CDR1, CDR2, and CDR3, wherein 1, 2, 3, 4, or 5 amino acids differ in at least one of the amino acid sequences selected from the group consisting of SEQ ID NOs: 26, 27, and 28. In some embodiments, the antigen binding domain is a VHH fragment consisting of a combination of CDR1, CDR2, and CDR3 selected from the group consisting of SEQ ID NOs: 26, 27, and 28.

[0162] In some embodiments, the antigen binding domain is a VHH fragment comprising an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 29. In some embodiments, the antigen binding domain is a VHH fragment comprising the amino acid sequence of SEQ ID NO: 29.

[0163] In some embodiments, the antigen binding domain is a VHH fragment consisting of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 29. In some embodiments, the antigen binding domain is a VHH fragment consisting of the amino acid sequence of SEQ ID NO: 29.

[0164] Connectors

[0165] The antigen binding domain can be linked to the N-terminus or C-terminus of the FcRn binding molecule (e.g., Fc domain). Alternatively, the antigen binding domain can be linked to a position other than the N-terminus or C-terminus of the FcRn binding molecule (e.g., Fc domain).

[0166] In some embodiments, the antigen binding domain may be non-covalently linked to the FcRn binding molecule. In some embodiments, the antigen binding domain may be covalently linked to the FcRn binding molecule.

[0167] In some embodiments, the antigen binding domain can be directly connected (e.g., fused) to the N-terminus or C-terminus of the FcRn binding molecule. In some embodiments, the antigen binding domain is connected to the N-terminus or C-terminus of the FcRn binding molecule via a linker. In some embodiments, the linker is a non-cleavable linker.

[0168] In some embodiments, the antigen binding domain can be directly connected (e.g., fused) to the N-terminus or C-terminus of the Fc domain. In some embodiments, the antigen binding domain is connected to the N-terminus or C-terminus of the Fc domain via a joint. In some embodiments, the joint is a non-cleavable joint. As used herein, the term "non-cleavable joint" refers to a joint that is not easily cut by one or more of a given enzyme, chemical agent, or light irradiation. In some embodiments, the enzyme is a protease.

[0169] In some embodiments, the linker is a synthetic compound linker, such as, for example, a chemical cross-linking agent. Non-limiting examples of commercially available suitable cross-linking agents include N-hydroxysuccinimide (NHS), disuccinimidyl suberate (DSS), bis(sulfosuccinimidyl) suberate (BS3), dithiobis(succinimidyl propionate) (DSP), dithiobis(sulfosuccinimidyl propionate) (DTSSP), ethylene glycol bis(succinimidyl succinate) (EGS), ethylene glycol bis(sulfosuccinimidyl succinate) (sulfo-EGS), disuccinimidyl tartrate (DST), disulfosuccinimidyl tartrate (sulfo-DST), bis[2-(succinimidyloxycarbonyloxy)ethyl]sulfone (BSOCOES) and bis[2-(sulfosuccinimidyloxycarbonyloxy)ethyl]sulfone (sulfo-BSOCOES).

[0170] As described above, the Fc domain disclosed herein may include a portion of a hinge region. Therefore, the antigen binding domain can be connected to the N-terminus of the Fc domain via the hinge region. In some embodiments, one or more amino acids are included between the C-terminus of the antigen binding domain and the N-terminus of the Fc domain. In some embodiments, the one or more amino acids included between the C-terminus of the antigen binding domain and the N-terminus of the Fc domain are amino acids of a native hinge region. In some embodiments, the C-terminus of the antigen binding domain is fused to the N-terminus of the Fc domain via the hinge region or a portion thereof. In some embodiments, the hinge region is an IgG hinge region, such as a human IgG hinge region.

[0171] In some embodiments, the linker is a peptide linker. Examples of peptide linkers are well known, and one skilled in the art can select a suitable peptide linker for linking the antigen binding domain to an FcRn binding molecule, such as an Fc domain.

[0172] The peptide linker can be any length. In some embodiments, the length and amino acid composition of the linker peptide sequence can be optimized to change the orientation and / or proximity of the polypeptide domains to each other to achieve the desired activity of the FcRn / antigen binding molecule. In some embodiments, the length of the peptide linker is between about 1 and about 100 amino acids, between about 8 and about 40 amino acids, or between about 15 amino acids and about 25 amino acids. In some embodiments, the length of the peptide linker is between 1 and 100 amino acids, between 8 and 40 amino acids, or between 15 and 25 amino acids. In some embodiments, the peptide linker is about 8 amino acids in length, about 9 amino acids in length, about 10 amino acids in length, about 11 amino acids in length, about 12 amino acids in length, about 13 amino acids in length, about 14 amino acids in length, about 15 amino acids in length, about 16 amino acids in length, about 17 amino acids in length, about 18 amino acids in length, about 19 amino acids in length, about 20 amino acids in length, about 21 amino acids in length, about 22 amino acids in length, about 23 amino acids in length, about 24 amino acids in length, about 25 amino acids in length, about 26 amino acids in length, about 27 amino acids in length, about 28 amino acids in length, about 29 amino acids in length, about 30 amino acids in length, about 31 amino acids in length, about 32 amino acids in length, about 33 amino acids in length, about 34 amino acids in length, about 35 amino acids in length, about 36 amino acids in length, about 37 amino acids in length, about 38 amino acids in length, about 39 amino acids in length or about 40 amino acids in length. In some embodiments, the peptide linker is 8 amino acids in length, 9 amino acids in length, 10 amino acids in length, 11 amino acids in length, 12 amino acids in length, 13 amino acids in length, 14 amino acids in length, 15 amino acids in length, 16 amino acids in length, 17 amino acids in length, 18 amino acids in length, 19 amino acids in length, 20 amino acids in length, 21 amino acids in length, 22 amino acids in length, 23 amino acids in length, 24 amino acids in length, 25 amino acids in length, 26 amino acids in length, 27 amino acids in length, 28 amino acids in length, 29 amino acids in length, 30 amino acids in length, 31 amino acids in length, 32 amino acids in length, 33 amino acids in length, 34 amino acids in length, 35 amino acids in length, 36 amino acids in length, 37 amino acids in length, 38 amino acids in length, 39 amino acids in length, or 40 amino acids in length.

[0173] In some embodiments, the peptide linker contains only glycine and / or serine residues (e.g., glycine-serine linker or GS linker). Examples of such peptide linkers include: Gly(x)Ser, wherein x is 0 to 6; or Ser Gly(x), wherein x is 0 to 6; (Gly Gly Gly Gly Ser)n, wherein n is an integer of 1 or greater; and (Ser Gly Gly Gly Gly)n, wherein n is an integer of 1 or greater. In some embodiments, the peptide linker includes an amino acid sequence selected from the group consisting of: (GGGGS)n and (SGGGG)n, wherein n is 1 to 8. In some embodiments, the linker peptide is modified so that the amino acid sequence GSG (which appears at the junction of the traditional Gly / Ser linker peptide repeats) is not present. For example, in some embodiments, the peptide linker includes an amino acid sequence selected from the group consisting of: (GGGXX)nGGGGS and GGGGS(XGGGS)n, wherein X is any amino acid that can be inserted into the sequence and does not produce a polypeptide comprising the sequence GSG, and n is 0 to 4. In some embodiments, the sequence of the linker peptide is (GGGX1X2)nGGGGS, and X1 is P and X2 is S and n is 0 to 4. In some other embodiments, the sequence of the linker peptide is (GGGX1X2)nGGGGS, and X1 is G and X2 is Q and n is 0 to 4. In some other embodiments, the sequence of the linker peptide is (GGGX1X2)nGGGGS, and X1 is G and X2 is A and n is 0 to 4. In yet other embodiments, the sequence of the linker peptide is GGGGS(XGGGS)n, and X is P and n is 0 to 4. In some embodiments, the linker peptide of the present disclosure comprises or consists of the amino acid sequence (GGGGA)2GGGGS. In some embodiments, the linker peptide comprises or consists of the amino acid sequence (GGGGQ)2GGGGS. In another embodiment, the linker peptide comprises or consists of the amino acid sequence (GGGPS)2GGGGS. In another embodiment, the linker peptide comprises the amino acid sequence GGGGS (PGGGS) 2 or consists of it. In yet another embodiment, the linker peptide comprises the amino acid sequence GSGGS or SGGSGS or consists of it. In some embodiments, the linker peptide comprises the amino acid sequence GGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 30), GGGGSGGGGS (SEQ ID NO: 31) or GGGGSGGGGSGGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 32) or consists of it.

[0174] In some embodiments, the peptide linker is a GS linker of about 20 or about 30 amino acids in length. In some embodiments, the peptide linker is a GS linker of 20 or 30 amino acids in length.

[0175] Heavy chain molecule

[0176] In some embodiments, the FcRn / antigen binding molecule may comprise a first heavy chain as described herein. In some embodiments, the first heavy chain comprises an Fc domain and an antigen binding domain connected by a joint. In some embodiments, the FcRn / antigen binding molecule may further comprise a second heavy chain as described herein. In some embodiments, the second heavy chain comprises an Fc domain and an antigen binding domain connected by a joint. In some embodiments, the second heavy chain comprises an Fc domain. In some embodiments, the first heavy chain and the second heavy chain are the same. In some embodiments, the first heavy chain and the second heavy chain are different.

[0177] In some embodiments, the first heavy chain and the second heavy chain have the same Fc domain. In some embodiments, the first heavy chain and the second heavy chain have different Fc domains. In some embodiments, the first heavy chain comprises an Fc domain and an antigen binding domain, while the second heavy chain comprises Fc but does not comprise an antigen binding domain. In some embodiments, the first heavy chain comprises an Fc domain and an antigen binding domain, while the second heavy chain comprises an Fc domain but does not comprise an antigen binding domain or a joint. In some embodiments, the first heavy chain comprises an Fc domain, an antigen binding domain, and a joint, while the second heavy chain comprises an Fc domain but does not comprise an antigen binding domain or a joint.

[0178] In some embodiments, the antigen binding domain is attached to the N-terminus of the Fc domain. In some embodiments, the antigen binding domain is attached to the C-terminus of the Fc domain. In some embodiments, the antigen binding domain is attached to a position other than the N-terminus or C-terminus of the Fc domain.

[0179] In some embodiments, the antigen binding domain is fused to the N-terminus of the Fc domain. In some embodiments, the antigen binding domain is fused to the C-terminus of the Fc domain. In some embodiments, the antigen binding domain is fused to a position other than the N-terminus or C-terminus of the Fc domain.

[0180] In some embodiments, the antigen binding domain is connected to the N-terminus of the Fc domain via a linker. In some embodiments, the antigen binding domain is connected to the C-terminus of the Fc domain via a linker. In some embodiments, the antigen binding domain is connected to a position other than the N-terminus or C-terminus of the Fc domain via a linker.

[0181] In some embodiments, the antigen binding domain is fused to the N-terminus of the Fc domain via a peptide linker. In some embodiments, the antigen binding domain is fused to the C-terminus of the Fc domain via a peptide linker. In some embodiments, the antigen binding domain is fused to a position other than the N-terminus or C-terminus of the Fc domain via a peptide linker.

[0182] In some embodiments, the Fc domain comprises an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 1-9. In some embodiments, the Fc domain consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 1-9.

[0183] In some embodiments, the Fc domain comprises the amino acid sequence of any one of SEQ ID NOs: 1-9. In some embodiments, the Fc domain consists of the amino acid sequence of any one of SEQ ID NOs: 1-9.

[0184] In some embodiments, the first heavy chain and the second heavy chain comprise the same Fc domain. In some embodiments, both the first heavy chain and the second heavy chain comprise an Fc domain, which comprises an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NO: 1-3. In some embodiments, both the first heavy chain and the second heavy chain comprise an Fc domain, which consists of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NO: 1-3. In some embodiments, both the first heavy chain and the second heavy chain comprise an Fc domain, which comprises an amino acid sequence of any one of SEQ ID NO: 1-3. In some embodiments, both the first heavy chain and the second heavy chain comprise an Fc domain, which consists of an amino acid sequence of any one of SEQ ID NO: 1-3.

[0185] In some embodiments, the first heavy chain and the second heavy chain comprise different Fc domains. In some embodiments, the first heavy chain comprises an Fc domain comprising an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 4-6, and the second heavy chain comprises an Fc domain comprising an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 7-9. In some embodiments, the first heavy chain comprises an Fc domain consisting of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 4-6, and the second heavy chain comprises an Fc domain consisting of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 7-9. In some embodiments, the first heavy chain comprises an Fc domain comprising an amino acid sequence of any one of SEQ ID NOs: 4-6, and the second heavy chain comprises an Fc domain comprising an amino acid sequence of any one of SEQ ID NOs: 7-9. In some embodiments, when the first heavy chain comprises an Fc domain comprising an amino acid sequence of SEQ ID NO: 4 or a variant thereof, the second heavy chain comprises an Fc domain comprising SEQ ID NO: 7 or a variant thereof. In some embodiments, when the first heavy chain comprises an Fc domain comprising an amino acid sequence of SEQ ID NO: 5 or a variant thereof, the second heavy chain comprises an Fc domain comprising SEQ ID NO: 8 or a variant thereof. In some embodiments, when the first heavy chain comprises an Fc domain comprising an amino acid sequence of SEQ ID NO: 6 or a variant thereof, the second heavy chain comprises an Fc domain comprising SEQ ID NO: 9 or a variant thereof.

[0186] In some embodiments, the first heavy chain and the second heavy chain further comprise a peptide linker. In some embodiments, the first heavy chain and the second heavy chain further comprise the same peptide linker. In some embodiments, the first heavy chain and the second heavy chain further comprise different peptide linkers. In some embodiments, the first heavy chain comprises an Fc domain, a peptide linker and an antigen binding domain, and the second heavy chain comprises an Fc domain but does not comprise a peptide linker or an antigen binding domain. The peptide linker encoded by the first chain and the heavy chain can be any peptide linker described herein. In some embodiments, the linker comprises an amino acid sequence of SEQ ID NO:30, 31 or 32.

[0187] In some embodiments, the FcRn / antigen binding molecule comprises or consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 34. In some embodiments, the FcRn / antigen binding molecule comprises or consists of the amino acid sequence of SEQ ID NO: 34.

[0188] In some embodiments, the FcRn / antigen binding molecule comprises the amino acid sequence of SEQ ID NO: 34 or a variant thereof and one or more amino acids added at the C-terminus. In some embodiments, the FcRn / antigen binding molecule comprises the amino acid sequence of SEQ ID NO: 34 or a variant thereof and one or more amino acids selected from A, AG, GG and PP added at the C-terminus.

[0189] In some embodiments, the first heavy chain of the FcRn / antigen binding molecule comprises or consists of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 34, and the second heavy chain of the FcRn / antigen binding molecule does not comprise an antigen binding domain. In some embodiments, the second heavy chain of the FcRn / antigen binding molecule comprises an Fc domain but does not comprise an antigen binding domain. Optionally, the second heavy chain of the FcRn / antigen binding molecule comprises or consists of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 8.

[0190] In some embodiments, the first heavy chain of the FcRn / antigen binding molecule comprises or consists of the amino acid sequence of SEQ ID NO: 34, and the second heavy chain of the FcRn / antigen binding molecule does not comprise an antigen binding domain. In some embodiments, the second heavy chain of the FcRn / antigen binding molecule comprises an Fc domain but does not comprise an antigen binding domain. Optionally, the second heavy chain of the FcRn / antigen binding molecule comprises or consists of the amino acid sequence of SEQ ID NO: 8.

[0191] Polynucleotides, vectors and methods of producing

[0192] The present disclosure also provides polynucleotides encoding FcRn / antigen binding molecules disclosed herein or fragments thereof. In some embodiments, polynucleotides encode antigen binding domains of the present disclosure. In some embodiments, polynucleotides encode FcRn binding molecules of the present disclosure. In some embodiments, polynucleotides encode Fc regions of the present disclosure. In some embodiments, polynucleotides encode Fc domains of the present disclosure. In some embodiments, polynucleotides encode one or more of antigen binding domains, FcRn binding molecules, and joints. In some embodiments, polynucleotides encode antigen binding domains and FcRn binding molecules, and optionally joints. In some embodiments, polynucleotides encode one or more of antigen binding domains, Fc regions, and joints. In some embodiments, polynucleotides encode antigen binding domains and Fc regions, and optionally joints. In some embodiments, polynucleotides encode FcRn / antigen binding molecules comprising an antigen binding domain and Fc regions. In some embodiments, polynucleotides encode one or more of antigen binding domains, Fc domains, and joints. In some embodiments, polynucleotides encode antigen binding domains and Fc domains, and optionally joints. In some embodiments, the polynucleotide encodes an FcRn / antigen binding molecule comprising one antigen binding domain and one or more Fc domains. In some embodiments, the polynucleotide encodes one or more heavy chains of the disclosure.

[0193] As used herein, "isolated" polynucleotides or nucleic acid molecules are polynucleotides or nucleic acid molecules that are separated from other nucleic acid molecules present in the natural source of nucleic acid molecules (e.g., in mice or humans). In addition, "isolated" nucleic acid molecules, such as cDNA molecules, can be substantially free of other cellular materials or culture media when produced by recombinant technology, or substantially free of chemical precursors or other chemicals when chemically synthesized. For example, the wording "substantially free" includes preparations of polynucleotides or nucleic acid molecules with less than about 15%, 10%, 5%, 2%, 1%, 0.5% or 0.1% (particularly less than about 10%) of other substances (e.g., cellular materials, culture media, other nucleic acid molecules, chemical precursors and / or other chemicals). In one embodiment, the nucleic acid molecules encoding the polypeptides described herein are separated or purified.

[0194] In one aspect, provided herein are polynucleotides comprising nucleotide sequences encoding FcRn binding molecules or FcRn / antigen binding molecules described herein. In another aspect, provided herein are polynucleotides comprising nucleotide sequences encoding antigen binding domains described herein. In another aspect, provided herein are polynucleotides comprising nucleotide sequences encoding FcRn / antigen binding molecules described herein. In another aspect, provided herein are polynucleotides comprising nucleotide sequences encoding FcRn binding molecules or FcRn / antigen binding molecules described herein.

[0195] The polynucleotide may include a nucleotide sequence encoding an sdAb (e.g., VHH fragment), a Fab fragment, a scFv, a VH or a VL comprising the FR and CDR of the antigen-binding domain described herein. The polynucleotide may also include a nucleotide sequence encoding an antibody mimetic as described herein. In some embodiments, the polynucleotide may include a nucleotide sequence encoding a VHH fragment, which VHH fragment includes the FR and CDR of the antigen-binding domain described herein. In some embodiments, the polynucleotide may include a nucleotide sequence encoding a light chain comprising a VL FR and CDR of an antigen-binding domain described herein or a nucleotide sequence encoding a heavy chain comprising a VH FR and CDR of an antigen-binding domain described herein and / or an Fc domain as described herein. In one embodiment, the polynucleotide encodes the VH, VL, heavy chain and / or light chain of the antigen-binding domain described herein. In one embodiment, the polynucleotide encodes the first VH and the first VL of the antigen-binding domain described herein. In one embodiment, the polynucleotide encodes the second VH and the second VL of the antigen-binding domain described herein. In one embodiment, the polynucleotide encodes the first heavy chain and the first light chain of the antigen-binding domain described herein. In one embodiment, the polynucleotide encodes a second heavy chain and a second light chain of an antigen binding domain described herein. In one embodiment, the polynucleotide encodes a VH and / or VL, or a heavy chain and / or a light chain of an antigen binding domain described herein.

[0196] In some embodiments, the polynucleotide may include a nucleotide sequence encoding a first heavy chain as described herein. In some embodiments, the first heavy chain includes an Fc domain and an antigen binding domain connected by a joint. In some embodiments, the polynucleotide may include a nucleotide sequence encoding a second heavy chain as described herein. In some embodiments, the second heavy chain includes an Fc domain and an antigen binding domain connected by a joint. In some embodiments, the first heavy chain and the second heavy chain are the same. In some embodiments, the first heavy chain and the second heavy chain are different.

[0197] In some embodiments, the first heavy chain and the second heavy chain have the same Fc domain. In some embodiments, the first heavy chain and the second heavy chain have different Fc domains. In some embodiments, the second heavy chain comprises an Fc domain but does not comprise an antigen binding domain, while the first heavy chain comprises an Fc domain and an antigen binding domain. In some embodiments, the second heavy chain comprises an Fc domain but does not comprise an antigen binding domain or a joint, while the first heavy chain comprises an Fc domain and an antigen binding domain. In some embodiments, the second heavy chain comprises an Fc domain but does not comprise an antigen binding domain or a joint, while the first heavy chain comprises an Fc domain and an antigen binding domain and a joint.

[0198] In some embodiments, the polynucleotide comprises a nucleotide sequence encoding an Fc domain comprising an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 1-9. In some embodiments, the polynucleotide consists of a nucleotide sequence encoding an Fc domain comprising an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 1-9.

[0199] In some embodiments, the polynucleotide comprises a nucleotide sequence encoding an Fc domain comprising the amino acid sequence of any one of SEQ ID NOs: 1-9. In some embodiments, the polynucleotide comprises a nucleotide sequence encoding an Fc domain consisting of the amino acid sequence of any one of SEQ ID NOs: 1-9.

[0200] In some embodiments, the polynucleotide comprises a nucleotide sequence encoding two or more Fc domains. In some embodiments, the polynucleotide comprises a nucleotide sequence encoding two Fc domains. In some embodiments, the polynucleotide comprises a first nucleotide sequence encoding a first Fc domain and a second nucleotide sequence encoding a second Fc domain. In some embodiments, the first nucleotide sequence and the second nucleotide sequence are contained in different nucleic acid molecules. In some embodiments, the first nucleotide sequence and the second nucleotide sequence are contained in the same nucleic acid molecule.

[0201] In some embodiments, the first nucleotide sequence and the second nucleotide sequence encode the same Fc domain. In some embodiments, both the first nucleotide sequence and the second nucleotide sequence encode an Fc domain, which comprises an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NO: 1-3. In some embodiments, both the first nucleotide sequence and the second nucleotide sequence encode an Fc domain, which consists of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NO: 1-3. In some embodiments, both the first nucleotide sequence and the second nucleotide sequence encode an Fc domain comprising an amino acid sequence of any one of SEQ ID NO: 1-3. In some embodiments, both the first nucleotide sequence and the second nucleotide sequence encode an Fc domain consisting of an amino acid sequence of any one of SEQ ID NO: 1-3.

[0202] In some embodiments, the first nucleotide sequence and the second nucleotide sequence encode different Fc domains. In some embodiments, the first nucleotide sequence encodes an Fc domain comprising an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 4-6, and the second nucleotide sequence encodes an Fc domain comprising an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 7-9. In some embodiments, the first nucleotide sequence encodes an Fc domain consisting of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 4-6, and the second nucleotide sequence encodes an Fc domain consisting of an amino acid sequence at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of any one of SEQ ID NOs: 7-9. In some embodiments, the first nucleotide sequence encodes an Fc domain comprising an amino acid sequence of any one of SEQ ID NOs: 4-6, and the second nucleotide sequence encodes an Fc domain comprising an amino acid sequence of any one of SEQ ID NOs: 7-9. In some embodiments, the first nucleotide sequence encodes an Fc domain consisting of an amino acid sequence of any one of SEQ ID NOs: 4-6, and the second nucleotide sequence encodes an Fc domain consisting of an amino acid sequence of any one of SEQ ID NOs: 7-9. In some embodiments, when the first nucleotide sequence encodes the amino acid sequence of SEQ ID NO: 4 or a variant thereof, the second nucleotide sequence encodes SEQ ID NO: 7 or a variant thereof. In some embodiments, when the first nucleotide sequence encodes the amino acid sequence of SEQ ID NO: 5 or a variant thereof, the second nucleotide sequence encodes SEQ ID NO: 8 or a variant thereof. In some embodiments, when the first nucleotide sequence encodes the amino acid sequence of SEQ ID NO: 6 or a variant thereof, the second nucleotide sequence encodes SEQ ID NO: 9 or a variant thereof.

[0203] In some embodiments, the first nucleotide sequence encodes an Fc domain and an antigen binding domain, and the second nucleotide sequence encodes an Fc domain but does not encode an antigen binding domain. The antigen binding domain encoded by the first nucleotide sequence and / or the second nucleotide sequence can be any antigen binding domain described herein.

[0204] In some embodiments, the first nucleotide sequence and the second nucleotide sequence also encode a peptide joint. In some embodiments, the first nucleotide sequence and the second nucleotide sequence encode the same peptide joint. In some embodiments, the first nucleotide sequence and the second nucleotide sequence encode different peptide joints. In some embodiments, the first nucleotide sequence encodes an Fc domain, a peptide joint and an antigen-binding domain, and the second nucleotide sequence encodes an Fc domain but does not encode a peptide joint or an antigen-binding domain. In some embodiments, the first nucleotide sequence encodes an antigen-binding domain, a peptide joint and an Fc domain, and the second nucleotide sequence encodes an Fc domain but does not encode a peptide joint or an antigen-binding domain. The peptide joint encoded by the first nucleotide sequence and / or the second nucleotide sequence can be any peptide joint as described herein. In some embodiments, the joint comprises an amino acid sequence of SEQ ID NO:30, 31 or 32.

[0205] In some embodiments, the polynucleotide comprises a nucleotide sequence encoding a protein comprising or consisting of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:34.

[0206] In some embodiments, the polynucleotide comprises a nucleotide sequence encoding a protein comprising or consisting of the amino acid sequence of SEQ ID NO:34.

[0207] In some embodiments, the first nucleotide sequence encodes a protein comprising or consisting of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 34, and the second nucleotide sequence encodes an Fc domain but does not encode an antigen binding domain. Optionally, the second nucleotide sequence encodes a protein comprising an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 8.

[0208] In some embodiments, the first nucleotide sequence encodes a protein comprising the amino acid sequence of SEQ ID NO: 34, and the second nucleotide sequence encodes an Fc domain, but does not encode an antigen binding domain. Optionally, the second nucleotide sequence encodes a protein comprising the amino acid sequence of SEQ ID NO: 8. In some embodiments, the first nucleotide sequence comprises a nucleotide sequence encoding a protein consisting of the amino acid sequence of SEQ ID NO: 34, and the second nucleotide sequence encodes an Fc domain, but does not encode an antigen binding domain. Optionally, the second nucleotide sequence encodes a protein consisting of the amino acid sequence of SEQ ID NO: 8.

[0209] In some embodiments, a third nucleotide sequence encoding a light chain is provided. In some embodiments, the third nucleotide sequence encodes an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 24, or a protein consisting thereof. In some embodiments, the third nucleotide sequence encodes a protein that is or consists of an amino acid sequence of SEQ ID NO: 24.

[0210] Also provided herein is a polynucleotide encoding a polypeptide as provided above, which is optimized, for example, by codon / RNA optimization, replacement with a heterologous signal sequence and elimination of mRNA instability elements. The method for generating an optimized nucleic acid for recombinant expression by introducing codon changes and / or eliminating the inhibitory zone in mRNA can be performed by adjusting accordingly, for example, U.S. Patent Nos. 5,965,726; 6,174,666; 6,291,664; 6,414,132; and the optimization method described in 6,794,498, all of which are incorporated herein by reference in their entirety. For example, potential splicing sites and unstable elements (e.g., elements rich in A / T or A / U) in RNA can be mutated without changing the amino acid encoded by the nucleic acid sequence to increase the stability of the RNA for recombinant expression. These changes utilize the degeneracy of the genetic code, for example, using alternative codons of the same amino acid. In one embodiment, one or more codons may need to be changed to encode conservative mutations, for example, similar amino acids with chemical structures and properties and / or functions similar to the original amino acids.

[0211] Polynucleotides can be obtained by any method known in the art, and the nucleotide sequence of the polynucleotides is determined. The nucleotide sequence encoding the protein described herein and the modified form of these antibodies can be determined using methods well known in the art, i.e., the nucleotide codons known to encode specific amino acids are assembled in a manner to generate nucleic acids encoding proteins. Such polynucleotides encoding proteins can be assembled from chemically synthesized oligonucleotides (e.g., as described in Kutmeier G et al., (1994) BioTechniques 17: 242-6, which is incorporated herein by reference in its entirety), in short, it involves synthesizing overlapping oligonucleotides containing sequence portions encoding antibodies, annealing and connection of these oligonucleotides, and then amplifying the connected oligonucleotides by PCR.

[0212] Alternatively, polynucleotides encoding proteins described herein can be generated from nucleic acids from suitable sources (e.g., hybridomas) using methods well known in the art (e.g., PCR and other molecular cloning methods). For example, PCR amplification using synthetic primers that hybridize to the 3' and 5' ends of known sequences can be performed using genomic DNA obtained from hybridoma cells that produce a polypeptide of interest. Such PCR amplification methods can be used to obtain nucleic acids comprising sequences encoding polypeptides. Amplified nucleic acids can be cloned into vectors for expression in host cells and for further cloning.

[0213] If a clone containing a nucleic acid encoding a particular polypeptide is not available, but the sequence of the polypeptide is known, the nucleic acid encoding the polypeptide can be chemically synthesized or obtained from a suitable source (e.g., a cDNA library generated from nucleic acid (preferably poly A+RNA) isolated from any tissue or cell expressing the polypeptides described herein) by PCR amplification using synthetic primers that hybridize to the 3' and 5' ends of the sequence, or by cloning using oligonucleotide probes specific for a particular gene sequence to identify, for example, cDNA clones from a cDNA library encoding the polypeptide. The amplified nucleic acid generated by PCR can then be cloned into a replicable cloning vector using any method well known in the art.

[0214] DNA encoding the proteins described herein can be readily isolated and sequenced using conventional methods. Hybridoma cells can serve as a source of such DNA. Once isolated, the DNA can be placed in an expression vector, which is then transfected into a host cell, such as an E. coli cell, a simian COS cell, a Chinese hamster ovary (CHO) cell (e.g., from a CHO GS System TM (Lonza) CHO cells) or myeloma cells that do not otherwise produce the proteins described herein.

[0215] Also provided are polynucleotides that hybridize under high stringency, medium or lower stringency hybridization conditions to a polynucleotide encoding a protein described herein.

[0216] Hybridization conditions have been described in the art and are known to those skilled in the art. For example, hybridization under stringent conditions may include DNA hybridization bound to a filter in 6x sodium chloride / sodium citrate (SSC) at about 45°C, followed by one or more washes in 0.2xSSC / 0.1% SDS at about 50°C-65°C; hybridization under highly stringent conditions may involve nucleic acid hybridization bound to a filter in 6xSSC at about 45°C, followed by one or more washes in 0.1xSSC / 0.2% SDS at about 68°C. Hybridization under other stringent hybridization conditions is known to those skilled in the art and has been described, see, e.g., Ausubel FM et al., eds., (1989) Current Protocols in Molecular Biology, Vol. I, Green Publishing Associates, Inc. and John Wiley & Sons, Inc., New York, pp. 6.3.1-6.3.6 and 2.10.3, which are incorporated herein by reference in their entirety.

[0217] In one aspect, cells (e.g., host cells) expressing (e.g., recombinantly) proteins described herein are provided herein, as well as related polynucleotides and expression vectors. Vectors (e.g., expression vectors) comprising polynucleotides are provided herein, which comprise nucleotide sequences encoding proteins described herein for recombinant expression in host cells, preferably mammalian cells (e.g., CHO cells). Host cells comprising such vectors for recombinantly expressing proteins described herein are also provided herein. In one aspect, methods for producing proteins described herein are provided herein, comprising expressing polypeptides from host cells.

[0218] The recombinant expression of proteins described herein generally involves constructing an expression vector containing a polynucleotide encoding a polypeptide. Once a polynucleotide encoding a polypeptide described herein is obtained, a vector for producing a polypeptide can be produced by recombinant DNA technology using techniques well known in the art. Therefore, a method for preparing a protein by expressing a polynucleotide containing a polypeptide encoding nucleotide sequence is described herein. Methods well known to those skilled in the art can be used to construct an expression vector containing a polypeptide encoding sequence and appropriate transcription and translation control signals. These methods include, for example, in vitro recombinant DNA technology, synthetic technology, and in vivo gene recombination. A replicable vector is also provided, which comprises a nucleotide sequence encoding a polypeptide described herein that is operably linked to a promoter. Such vectors may, for example, include a nucleotide sequence encoding a first heavy chain of the present disclosure (see, for example, International Publication Nos. WO 86 / 05807 and WO 89 / 01036; and U.S. Patent No. 5,122,464, which are incorporated herein by reference in their entirety), and the second heavy chain of the present disclosure may be cloned into this vector for expressing the first heavy chain, the second heavy chain, or both the first heavy chain and the second heavy chain.

[0219] In one embodiment, the vector comprises a polynucleotide encoding a sdAb, a Fab fragment, a scFv, a VHH fragment, a VH, a VL, a heavy chain and / or a light chain of a polypeptide described herein. In another embodiment, the vector comprises a polynucleotide encoding a VH and a VL of a polypeptide described herein. In another embodiment, the vector comprises a polynucleotide encoding a heavy chain and a light chain of a polypeptide described herein.

[0220] The expression vector can be transferred to a cell (e.g., a host cell) by conventional techniques, and the resulting cell can then be cultured by conventional techniques to produce a polypeptide or fragment thereof as described herein. Therefore, provided herein is a host cell containing a polynucleotide encoding a polypeptide or fragment thereof as described herein, or a heavy chain or light chain thereof, or a fragment thereof, or a single-chain antibody as described herein, the polynucleotide being operably linked to a promoter for expressing such sequences in a host cell.

[0221] In one embodiment, the host cell comprises a polynucleotide containing one of the first nucleotide sequences and one of the second nucleotide sequences described above. In another embodiment, the host cell comprises a first polynucleotide containing one of the first nucleotide sequences described above and a second polynucleotide containing one of the first nucleotide sequences described above. In another embodiment, the host cell comprises a first vector containing one of the first nucleotide sequences described above and one of the second nucleotide sequences. In another embodiment, the host cell comprises a first vector containing one of the first nucleotide sequences described above and one of the second nucleotide sequences, and a second vector containing a second polynucleotide, the second polynucleotide comprising one of the first nucleotide sequences described above.

[0222] In some embodiments, the FcRn / antigen binding molecule expressed by the first host cell associates with the FcRn / antigen binding molecule expressed by the second host cell to form a two-armed FcRn / antigen binding molecule. In some embodiments, the FcRn / antigen binding molecule expressed by the first host cell associates with the FcRn binding molecule expressed by the second host cell to form a single-armed FcRn / antigen binding molecule. In some embodiments, provided herein is a host cell population comprising such a first host cell and such a second host cell.

[0223] In some embodiments, provided herein are vector populations comprising a first vector and a second vector, the first vector comprising a polynucleotide encoding an FcRn / antigen binding molecule, and the second vector comprising a polynucleotide encoding an FcRn / antigen binding molecule. In some embodiments, provided herein are vector populations comprising a first vector and a second vector, the first vector comprising a polynucleotide encoding an FcRn / antigen binding molecule, and the second vector comprising a polynucleotide encoding an FcRn binding molecule. In some embodiments, provided herein are vector populations comprising a first vector, the first vector comprising a polynucleotide encoding an FcRn / antigen binding molecule and a polynucleotide encoding an FcRn / antigen binding molecule. In some embodiments, provided herein are vector populations comprising a first vector, the first vector comprising a polynucleotide encoding two FcRn / antigen binding molecules.

[0224] A variety of host-expression vector systems can be used to express the polypeptides described herein (see, e.g., U.S. Pat. No. 5,807,715, which is incorporated herein by reference in its entirety). Such host-expression systems represent vehicles by which the coding sequences of interest can be produced and subsequently purified, but also represent cells that can express the polypeptides described herein in situ when transformed or transfected with the appropriate nucleotide coding sequences. These include, but are not limited to, microorganisms such as bacteria (e.g., Escherichia coli and Bacillus subtilis) transformed with, for example, recombinant bacteriophage DNA, plasmid DNA or cosmid DNA expression vectors containing FcRn / antigen binding molecule coding sequences; yeast (e.g., Saccharomyces and Pichia) transformed with, for example, recombinant yeast expression vectors containing FcRn / antigen binding molecule coding sequences; insect cell systems infected with, for example, recombinant virus expression vectors (e.g., baculovirus) containing FcRn / antigen binding molecule coding sequences; plant cell systems (e.g., green algae, such as Chlamydomonas reinhardtii) infected with, for example, recombinant virus expression vectors (e.g., cauliflower mosaic virus CaMV; tobacco mosaic virus TMV) or transformed with, for example, recombinant plasmid expression vectors (e.g., Ti plasmid) containing FcRn / antigen binding molecule coding sequences; or mammalian cell systems (e.g., COS (e.g., COS1 or COS), CHO, BHK, MDCK, HEK 293, NS0, PER.C6, VERO, CRL7030, HsS78Bst, HeLa, NIH 3T3, HEK-293T, HepG2, SP210, R1.1, BW, LM, BSC1, BSC40, YB / 20 and BMT10 cells), which contain, for example, a recombinant expression construct containing a promoter derived from the genome of a mammalian cell (e.g., a metallothionein promoter) or a promoter derived from a mammalian virus (e.g., adenovirus late promoter; vaccinia virus 7.5K promoter). In one embodiment, the cells used to express the FcRn / antigen binding molecules described herein are Chinese hamster ovary (CHO) cells, such as those from the CHO GS System TM In one embodiment, the heavy chain and / or light chain produced by the CHO cells may have an N-terminal glutamine or glutamic acid residue replaced by pyroglutamic acid. In one embodiment, the cells used to express the polypeptides described herein are human cells, such as human cell lines. In one embodiment, the mammalian expression vector is pOptiVEC TMOr pcDNA3.3. In one embodiment, bacterial cells such as Escherichia coli or eukaryotic cells (e.g., mammalian cells) are used to express recombinant polypeptides. For example, mammalian cells such as CHO cells, combined with vectors such as major intermediate early gene promoter elements from human cytomegalovirus, are effective expression systems for antibodies (Foecking MK and Hofstetter H (1986) Gene 45: 101-5; and Cockett MI et al., (1990) Biotechnology 8 (7): 662-7, each of which is incorporated herein by reference in its entirety). In one embodiment, the polypeptides described herein are produced by CHO cells or NS0 cells. In one embodiment, the expression of the nucleotide sequence encoding the polypeptides comprising two, three or four binding sites for human FcRn described herein is regulated by a constitutive promoter, an inducible promoter or a tissue-specific promoter.

[0225] In bacterial systems, many expression vectors can be advantageously selected according to the intended use of the molecule to be expressed. For example, when a large number of such polypeptides are to be produced, in order to produce a pharmaceutical composition of an antibody molecule, it may be necessary to instruct a carrier for the high-level expression of a fusion protein product that is easily purified. Such carriers include, but are not limited to, the E. coli expression vector pUR278 (Ruether U and Mueller-Hill B (1983) EMBO J 2: 1791-1794), in which the coding sequence can be individually connected to a carrier in a framework with a lac Z coding region, thereby producing a fusion protein; pIN vectors (Inouye S and Inouye M (1985) Nuc Acids Res 13: 3101-3109; Van Heeke G and Schuster SM (1989) J Biol Chem 24: 5503-5509); etc., all of which are incorporated herein by reference in their entirety. For example, pGEX vectors can also be used to express exogenous polypeptides as fusion proteins with glutathione 5-transferase (GST). In general, such fusion proteins are soluble and can be easily purified from lysed cells by adsorption and binding to matrix glutathione agarose beads followed by elution in the presence of free glutathione. pGEX vectors are designed to include thrombin or factor Xa protease cleavage sites so that the cloned target gene product can be released from the GST moiety.

[0226] For example, in insect systems, Autographa californica nuclear polyhedrosis virus (AcNPV) can be used as a vector for expressing foreign genes. The virus grows in Spodoptera frugiperda cells. The coding sequence can be cloned individually into a non-essential region of the virus (e.g., a polyhedrin gene) and placed under the control of an AcNPV promoter (e.g., a polyhedrin promoter).

[0227] In mammalian host cells, many virus-based expression systems can be used. In the case of using adenovirus as an expression vector, the coding sequence of interest can be connected to an adenovirus transcription / translation control complex, for example, a late promoter and a tripartite leader sequence. The chimeric gene can then be inserted into the adenovirus genome by in vitro or in vivo recombination. Insertion in a non-essential region of the viral genome (e.g., E1 region or E3 region) will produce a recombinant virus that is viable and capable of expressing the molecule in an infected host (see, e.g., Logan J and Shenk T (1984) PNAS 81 (12): 3655-9, which is incorporated herein by reference in its entirety). The effective translation of the inserted coding sequence may also require a specific start signal. These signals include an ATG start codon and adjacent sequences. In addition, the start codon must be in phase with the reading frame of the desired coding sequence to ensure translation of the entire insert. These exogenous translation control signals and start codons can have a variety of sources, including natural and synthetic. Expression efficiency may be enhanced by the inclusion of appropriate transcription enhancer elements, transcription terminators, and the like (see, e.g., Bitter G et al., (1987) Methods Enzymol. 153:516-544, which is incorporated herein by reference in its entirety).

[0228] In addition, host cell strains can be selected that regulate the expression of inserted sequences or modify and process gene products in a desired specific manner. Such modifications (e.g., glycosylation) and processing (e.g., cleavage) of protein products may be important for the function of the protein. Different host cells have characteristics and specific mechanisms for post-translational processing and modification of proteins and gene products. Suitable cell lines or host systems can be selected to ensure the correct modification and processing of the expressed foreign proteins. For this reason, eukaryotic host cells with cellular machinery for appropriate processing of primary transcripts, glycosylation and phosphorylation of gene products can be used. Such mammalian host cells include, but are not limited to, CHO, VERO, BHK, HeLa, MDCK, HEK 293, NIH 3T3, W138, BT483, Hs578T, HTB2, BT20 and T47D, NS0 (a murine myeloma cell line that does not endogenously produce any immunoglobulin chains), CRL7030, COS (e.g., COS1 or COS), PER.C6, VERO, HsS78Bst, HEK-293T, HepG2, SP210, R1.1, BW, LM, BSC1, BSC40, YB / 20, BMT10 and HsS78Bst cells. In one embodiment, the proteins described herein are produced in mammalian cells such as CHO cells.

[0229] In one embodiment, the polypeptides described herein comprise a portion of an antibody having reduced fucose content or no fucose content. Such proteins can be produced using techniques known to those skilled in the art. For example, the protein can be expressed in cells lacking or lacking fucosylation ability. In one example, a cell line with two alleles of α1,6-fucosyltransferase knocked out can be used to produce antibodies with reduced fucose content. The ANTIBODYNAMIC® system (Lonza) is an example of such a system that can be used to generate antibodies with reduced fucose content.

[0230] For long-term, high-yield production of recombinant proteins, stable expression cells can be generated. For example, cell lines that stably express the proteins described herein can be engineered. In one embodiment, cells provided herein stably express antigen binding domains, FcRn / antigen binding molecules or FcRn binding molecules that associate to form a single-armed polypeptide as described herein.

[0231] In some aspects, instead of using an expression vector containing a viral origin of replication, a host cell can be transformed with a DNA and a selectable marker controlled by appropriate expression control elements (e.g., promoters, enhancers, sequences, transcription terminators, polyadenylation sites, etc.). After introducing foreign DNA / polynucleotides, the engineered cell can be allowed to grow in an enriched medium for one to two days, and then switched to a selective medium. The selectable marker in the recombinant plasmid confers resistance to selection, and allows cells to stably integrate the plasmid into their chromosome and grow to form a focus, which can then be cloned and expanded into a cell line. The method can be advantageously used in a cell line of engineered expression polypeptides comprising two, three or four binding sites or fragments thereof for human FcRn as described herein. This type of engineered cell line can be particularly useful for screening and evaluating compositions that interact directly or indirectly with polypeptides.

[0232] A number of selection systems can be used, including but not limited to the herpes simplex virus thymidine kinase (Wigler M et al., (1977) Cell 11(1):223-32), hypoxanthine guanine phosphoribosyltransferase (Szybalska EH and Szybalski W (1962) PNAS 48(12):2026-2034), and adenine phosphoribosyltransferase (Lowy I et al., (1980) Cell 22(3):817-23) genes in tk cells, hgprt cells, or aprt cells, respectively, all of which are incorporated herein by reference in their entirety. In addition, antimetabolite resistance can be used as the basis for selection for the following genes: dhfr, which confers resistance to methotrexate (Wigler M et al., (1980) PNAS 77(6):3567-70; O'Hare K et al., (1981) PNAS 78:1527-31); gpt, which confers resistance to mycophenolic acid (Mulligan RC and Berg P (1981) PNAS 78(4):2072-6); neo, which confers resistance to the aminoglycoside G-418 (Wu GY and Wu CH (1991) Biotherapy 3:87-95; Tolstoshev P (1993) Ann Rev Pharmacol Toxicol 32:573-596; Mulligan RC (1993) Science 260:926-932; and Morgan RA and Anderson WF (1993) Ann Rev Biochem 62: 191-217; Nabel GJ and Felgner PL (1993) Trends Biotechnol 11(5):211-5); and hygro, which confers resistance to hygromycin (Santerre RF et al., (1984) Gene 30(1-3): 147-56), all of which are incorporated herein by reference in their entirety.Methods well known in the art of recombinant DNA technology can be routinely applied to select the desired recombinant clones, and such methods are described, for example, in Ausubel FM et al. (eds.), Current Protocols in Molecular Biology, John Wiley & Sons, NY (1993); Kriegler M, Gene Transfer and Expression, A Laboratory Manual, Stockton Press, NY (1990); and in Chapters 12 and 13, Dracopoli NC et al. (eds.), Current Protocols in Human Genetics, John Wiley & Sons, NY (1994); Colbère-Garapin F et al., (1981) J Mol Biol 150:1-14, all of which are incorporated herein by reference in their entirety.

[0233] The expression level of the polypeptide can be increased by vector amplification (for review, see, Bebbington CR and Hentschel CCG, The use of vectors based on gene amplification for the expression of cloned genes in mammalian cells in DNA cloning, pp. 163-188 in DNA Cloning, Vol. III, A Practical Approach. DM Glover (ed.) (Academic Press, New York, 1987), which is incorporated herein by reference in its entirety). When the marker in the vector system is amplifiable, an increase in the level of inhibitor present in the host cell culture will increase the copy number of the marker gene. Since the amplified region is associated with the gene of interest, the yield of the polypeptide will also increase (Crouse GF et al., (1983) Mol Cell Biol 3: 257-66, which is incorporated herein by reference in its entirety).

[0234] Host cells can be co-transfected with two or more expression vectors described herein. The two vectors can contain the same selectable marker, which enables polypeptides (such as the first heavy chain and the second heavy chain polypeptide) to be expressed equally. Host cells can be co-transfected with two or more expression vectors of different amounts. For example, host cells can be transfected with the first expression vector and the second expression vector of any one of the following ratios: about 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50.

[0235] Alternatively, a single vector encoding and capable of expressing two polypeptides can be used. The coding sequence can include cDNA or genomic DNA. The expression vector can be a monocistronic or polycistronic. The polycistronic nucleic acid construct can encode 2, 3, 4, 5, 6, 7, 8, 9, 10 or more genes / nucleotide sequences, or in the range of 2-5, 5-10 or 10-20 genes / nucleotide sequences. For example, a bicistronic nucleic acid construct can include a promoter, a first gene and a second gene in the following order. In this expression vector, the transcription of the two genes can be driven by the promoter, and the translation of the mRNA from the first gene can be carried out by a cap-dependent scanning mechanism, and the translation of the mRNA from the second gene can be carried out by a cap-independent mechanism, for example, by IRES.

[0236] Once a polypeptide described herein is produced by recombinant expression, it can be purified by any method known in the art for purifying proteins, such as by chromatography (e.g., ion exchange, affinity, particularly by affinity for a specific antigen after protein A, and sizing column chromatography), centrifugation, differential solubility, or by any other standard technique for purifying proteins. In addition, the polypeptides described herein can be fused to heterologous polypeptide sequences described herein or known in the art to facilitate purification.

[0237] In one embodiment, polypeptides described herein are separated or purified. In one embodiment, separated polypeptides are polypeptides that are substantially free of other polypeptides having different antigenic specificities from the separated polypeptides. For example, in certain embodiments, protein preparations described herein are substantially free of cellular material and / or chemical precursors. The wording "substantially free of cellular material" includes polypeptide preparations in which the polypeptide is separated from the cellular components of the cell that separates or recombinantly produces the polypeptide. Therefore, polypeptides substantially free of cellular material include polypeptide preparations with less than about 30%, 20%, 10%, 5%, 2%, 1%, 0.5% or 0.1% (by dry weight) of heterologous proteins (also referred to herein as "contaminating proteins") and / or polypeptide variants (e.g., different post-translational modified forms of polypeptides or other different versions of polypeptides (e.g., polypeptide fragments)). When the polypeptide is recombinantly produced, it is also generally substantially free of culture medium, i.e., culture medium accounts for less than about 20%, 10%, 2%, 1%, 0.5% or 0.1% of the volume of the protein preparation. When a polypeptide is produced by chemical synthesis, it is generally substantially free of chemical precursors or other chemicals, i.e., it is separated from chemical precursors or other chemicals involved in protein synthesis. Thus, such protein preparations have less than about 30%, 20%, 10% or 5% (by dry weight) of chemical precursors or compounds other than the molecule of interest. In one embodiment, the polypeptide described herein is isolated or purified.

[0238] The polypeptides described herein can be produced by any method known in the art for synthesizing proteins, such as by chemical synthesis or by recombinant expression techniques. Unless otherwise indicated, the methods described herein employ conventional techniques in molecular biology, microbiology, genetic analysis, recombinant DNA, organic chemistry, biochemistry, PCR, oligonucleotide synthesis and modification, nucleic acid hybridization, and related fields within the skill of the art. For example, these techniques are described in the references cited herein and are fully explained in the literature. See, e.g., Maniatis T et al., (1982) Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press; Sambrook J et al., (1989), Molecular Cloning: A Laboratory Manual, 2nd ed., Cold Spring Harbor Laboratory Press; Sambrook J et al., (2001) Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY; Ausubel FM et al., Current Protocols in Molecular Biology, John Wiley & Sons (1987 and annual updates); Current Protocols in Immunology, John Wiley & Sons (1987 and annual updates); Gait (ed.) (1984) Oligonucleotide Synthesis: A Practical Approach, IRL Press; Eckstein (ed.) (1991) Oligonucleotides and Analogues: A Practical Approach, IRL Press; Birren et al., Current Protocols in Molecular Biology, John Wiley & Sons (1987 and annual updates); B et al. (eds.) (1999) Genome Analysis: A Laboratory Manual, Cold Spring Harbor Laboratory Press, all of which are incorporated herein by reference in their entirety.

[0239] In one embodiment, the polypeptides described herein are prepared, expressed, produced or isolated by any means involving production, e.g., via synthesis of a DNA sequence, genetic engineering. In one embodiment, such polypeptides comprise sequences (e.g., DNA sequences or amino acid sequences) that are not naturally present in the antibody germline repertoire in an animal or mammal (e.g., human).

[0240] Pharmaceutical composition

[0241] On the one hand, the present disclosure provides a pharmaceutical composition comprising FcRn / antigen binding molecules or FcRn binding molecules as disclosed herein, which is used in the method for treating antibody-mediated diseases (e.g., autoantibody-mediated diseases). In certain embodiments, these compositions include FcRn / antigen binding molecules, which include FcRn binding molecules and antigen binding domains. In certain embodiments, these compositions include FcRn binding molecules connected to molecules that do not specifically bind to human proteins. In certain embodiments, FcRn binding molecules are FcRn antagonists. In certain embodiments, FcRn antagonists include variant Fc regions or their FcRn binding fragments that inhibit the binding of Fc regions of immunoglobulins to FcRn or are composed of them. In general, these FcRn antagonists inhibit the binding of Fc-containing agents (e.g., antibodies and immunoadhesins) to FcRn in vivo, which results in an increase in the degradation rate of Fc-containing agents and a decrease in the serum levels of these agents.

[0242] The FcRn / antigen binding molecules or FcRn binding molecules disclosed herein have a molecular weight ranging from about 50kDa (which is about one-third of the molecular weight of a full-length IgG (MW about 150kDa)) to about 140kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of 50kDa to 140kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of about 60kDa to about 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of 60kDa to 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of about 60kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of about 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a molecular weight of 60kDa. In some embodiments, the FcRn / antigen binding molecule or FcRn binding molecule has a molecular weight of 104 kDa.

[0243] In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules of the present disclosure have a predicted molecular weight ranging from about 50kDa (which is about one-third of the molecular weight of full-length IgG (MW about 150kDa)) to about 140kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a predicted molecular weight of 50kDa to 140kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a predicted molecular weight of about 60kDa to about 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a predicted molecular weight of 60kDa to 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a predicted molecular weight of about 60kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a predicted molecular weight of about 104kDa. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules have a predicted molecular weight of 60kDa. In some embodiments, the FcRn / antigen binding molecule or FcRn binding molecule has a predicted molecular weight of 104 kDa.

[0244] The formulations disclosed herein include bulk pharmaceutical compositions that can be used to make pharmaceutical compositions (e.g., compositions suitable for administration to subjects or patients), which can be used to prepare unit dosage forms. In one embodiment, the composition of the invention is a pharmaceutical composition. Such compositions comprise a preventive or therapeutically effective amount of one or more of the present invention's preventive or therapeutic agents (e.g., FcRn / antigen binding molecules) (or other preventive or therapeutic agents) and a pharmaceutically acceptable carrier.

[0245] In some embodiments, the pharmaceutical compositions are formulated for administration to a subject by any suitable route of administration, including but not limited to intramuscular, intravenous, intradermal, intraperitoneal, subcutaneous, epidural, nasal, oral, rectal, topical, inhaled, buccal (e.g., sublingual), and transdermal administration. In one embodiment, the pharmaceutical compositions are formulated to be suitable for intravenous administration to a subject. In one embodiment, the pharmaceutical compositions are formulated to be suitable for subcutaneous administration to a subject.

[0246] Treatment

[0247] The present disclosure also provides a method for treating an antibody-mediated disorder (e.g., an autoantibody-mediated disorder) in a subject, the method comprising administering to the subject a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule according to the present disclosure or a pharmaceutical composition comprising the same.

[0248] In some embodiments, the antibody-mediated disorder is an autoimmune disease. In some embodiments, the autoimmune disease is selected from the group consisting of: allogeneic pancreatic islet transplant rejection, alopecia areata, ankylosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, Alzheimer's disease, anti-neutrophil cytoplasmic autoantibodies (ANCA), adrenal autoimmune disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune myocarditis, autoimmune neutropenia, autoimmune oophoritis and orchitis, immune thrombocytopenia (ITP or idiopathic thrombocytopenic purpura, idiopathic thrombocytopenic purpura, immune-mediated thrombocytopenia or primary immune thrombocytopenia), autoimmune urticaria, Behcet's disease, bullous Pemphigus (BP), cardiomyopathy, Castleman's disease, celiac sprue, chronic fatigue immune dysfunction syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), Chargar-Strauss syndrome, cicatricial pemphigoid, CREST syndrome, cold agglutinin disease, Crohn's disease, dilated cardiomyopathy, discoid lupus, epidermolysis bullosa acquisita, essential mixed cryoglobulinemia, factor VIII deficiency, fibromyalgia-fibromyositis, glomerulonephritis, Graves' disease, Guillain-Barré syndrome, Goodpasture's syndrome, graft-versus-host disease (GVHD), Hashimoto's thyroiditis, hemophilia A, idiopathic inflammatory myopathy (IIM), idiopathic membranous neuropathy, idiopathic Pulmonary fibrosis, IgA neuropathy, IgM polyneuropathy, immune-mediated necrotizing myopathy (IMNM), juvenile arthritis, Kawasaki disease, lichen planus, atrophic lichen sclerosus, lupus erythematosus, lupus nephritis, Meniere's disease, mixed connective tissue disease, mucous membrane pemphigoid, multiple sclerosis, type 1 diabetes, multifocal motor neuropathy (MMN), myasthenia gravis (MG), generalized myasthenia gravis (gMG), myositis, paraneoplastic bullous pemphigoid, pemphigoid gestationis, pemphigus vulgaris (PV), pemphigus foliaceus (PF), pernicious anemia, polyarteritis nodosa, polychondritis, polyglandular syndrome, polymyalgia rheumatica, polymyositis, dermatomyositis (DM), Necrotizing autoimmune myopathy (NAM), antisynthetase syndrome (ASyS), primary agammaglobulinemia, primary biliary cirrhosis, psoriasis, psoriatic arthritis, relapsing polychondritis, Raynaud's phenomenon, Reiter's syndrome, rheumatoid arthritis, sarcoidosis, scleroderma, Sjögren's syndrome, solid organ transplant rejection, stiff-person syndrome, systemic lupus erythematosus, Takayasu's arteritis, toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), temporal arteritis / giant cell arteritis, thrombotic thrombocytopenic purpura, ulcerative colitis, uveitis, dermatitis herpetiformis, vasculitis, antineutrophil cytoplasmic antibody-associated vasculitis, vitiligo, and Wegener's granulomatosis.

[0249] In one embodiment, the FcRn / antigen binding molecule antagonizes the binding of FcRn to the Fc region of an antibody. In one embodiment, the FcRn / antigen binding molecule does not antagonize the binding of FcRn to albumin.

[0250] The present disclosure provides a method for reducing serum IgG in a subject, the method comprising administering to a subject a therapeutically effective amount of FcRn / antigen binding molecules or FcRn binding molecules according to the present disclosure or a pharmaceutical composition comprising the same. In one embodiment, after administering FcRn / antigen binding molecules or FcRn binding molecules, at least one of IgG subtypes in a subject is reduced. In certain embodiments, IgG1, IgG2, IgG3, IgG4 or any combination thereof is reduced. In certain embodiments, the administration of FcRn / antigen binding molecules or FcRn binding molecules is a single administration (e.g., a single therapeutic administration) of FcRn / antigen binding molecules or FcRn binding molecules. In one embodiment, after administering FcRn / antigen binding molecules or FcRn binding molecules, the level of serum IgG in a subject is reduced compared to the baseline level of serum IgG.

[0251] In one embodiment, at least about 35% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 45% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 40% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 45% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 50% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 55% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 60% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 65%, about 70%, about 75% or about 80% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 65% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 70% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 75% reduction in total serum IgG is obtained compared to baseline serum IgG levels. In one embodiment, at least about 80% reduction in total serum IgG is obtained compared to baseline serum IgG levels.

[0252] In one embodiment, after administration of the FcRn / antigen binding molecule or the FcRn binding molecule, the level of serum IgG in the subject is reduced compared to the baseline level of serum IgG. In one embodiment, a total serum IgG reduction of about 35% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 40% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 45% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 50% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 55% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 60% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 65%, about 70%, about 75% or about 80% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 65% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 70% is obtained compared to the baseline serum IgG level. In one embodiment, a total serum IgG reduction of about 75% is obtained compared to the baseline serum IgG level. In one embodiment, about an 80% reduction in total serum IgG compared to baseline serum IgG levels is achieved.

[0253] In one embodiment, after administration of the FcRn / antigen binding molecule or FcRn binding molecule, the level of FcRn in the subject is not reduced compared to the baseline level of FcRn. In one embodiment, a reduction of less than about 1%, 2%, 3%, 4% or 5% in FcRn is observed compared to the baseline FcRn level. In one embodiment, a reduction of less than about 10% in FcRn is observed compared to the baseline FcRn level.

[0254] In one embodiment, after administration of the FcRn / antigen binding molecule or FcRn binding molecule, the level of albumin in the subject is not reduced compared to the baseline level of albumin. In one embodiment, a reduction in albumin of less than about 1%, 2%, 3%, 4% or 5% compared to the baseline albumin level is observed. In one embodiment, a reduction in albumin of less than about 10% compared to the baseline albumin level is observed.

[0255] In one embodiment, the total IgG, FcRn / antigen binding molecules, FcRn binding molecules, FcRn or albumin in the serum sample of the patient are analyzed using a bioanalysis method. In one embodiment, the total IgG, FcRn / antigen binding molecules, FcRn binding molecules, FcRn or albumin in the serum sample of the patient are analyzed using ELISA or an automatic diagnostic analyzer (IVD). In one embodiment, the total IgG, FcRn / antigen binding molecules, FcRn binding molecules, FcRn or albumin in the serum sample of the patient are analyzed using ELISA. In one embodiment, the total IgG, FcRn / antigen binding molecules, FcRn binding molecules, FcRn or albumin in the serum sample of the patient are analyzed using an automatic diagnostic analyzer (IVD). In one embodiment, the total FcRn in the blood sample of the patient is analyzed using a bioanalysis method, preferably flow cytometry, microscopy or immunoblotting.

[0256] In some embodiments, the reduction in total serum IgG is measured by the area under the percent reduction curve (AUEC). In some embodiments, the reduction in total serum IgG is measured by the clearance rate (CL) of total serum IgG.

[0257] In some embodiments, after administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of total serum IgG in the subject is increased. In some embodiments, after a single therapeutic administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of total serum IgG in the subject is comparable to the clearance rate of total serum IgG in the subject after a single therapeutic administration of agamod. In some embodiments, after a single therapeutic administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of total serum IgG in the subject is similar or identical to the clearance rate of total serum IgG in the subject after a single therapeutic administration of agamod. In some embodiments, after a single therapeutic administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of total serum IgG in the subject is increased compared to the clearance rate of total serum IgG after a single therapeutic administration of agamod. In some embodiments, after a single therapeutic administration of the FcRn / antigen binding molecule or FcRn binding molecule, the clearance of total serum IgG in the subject is increased by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 125%, at least 150%, or at least 200% compared to the clearance of total serum IgG after a single therapeutic administration of igamod.

[0258] In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of total serum IgG in the subject is comparable to the clearance rate of total serum IgG in the subject after a single administration of an equal amount of agamod. In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of total serum IgG in the subject is similar or identical to the clearance rate of total serum IgG in the subject after a single administration of an equal amount of agamod. In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of total serum IgG in the subject is increased compared to the clearance rate of total serum IgG after a single administration of an equal amount of agamod. In some embodiments, after a single administration of the FcRn / antigen binding molecule or the FcRn binding molecule, the clearance of total serum IgG in the subject is increased by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 125%, at least 150% or at least 200% compared to the clearance of total serum IgG after a single administration of an equivalent amount of igamod.

[0259] In some embodiments, after a single therapeutic administration of an FcRn / antigen binding molecule or an FcRn binding molecule, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is reduced compared to the clearance rate of agamod after a single therapeutic administration of agamod. In some embodiments, after a single therapeutic administration of an FcRn / antigen binding molecule or an FcRn binding molecule, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is reduced by at least 1 times, at least 1.5 times, at least 2 times, at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, at least 10 times, at least 12 times, at least 15 times, or at least 20 times compared to the clearance rate of agamod after a single therapeutic administration of agamod.

[0260] In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of FcRn / antigen binding molecules or FcRn binding molecules in the subject is reduced compared to the clearance rate of agamod after a single administration of an equivalent amount of agamod. In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of FcRn / antigen binding molecules or FcRn binding molecules in the subject is reduced by at least 1 times, at least 1.5 times, at least 2 times, at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, at least 10 times, at least 12 times, at least 15 times or at least 20 times compared to the clearance rate of agamod after a single administration of an equivalent amount of agamod.

[0261] In some embodiments, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject after a single administration of the FcRn / antigen binding molecule or the FcRn binding molecule is less than about 0.2, about 0.19, about 0.18, about 0.17, about 0.16, about 0.15, about 0.14, about 0.13, about 0.12, about 0.11, about 0.1, about 0.09, about 0.08, about 0.07, about 0.06, or about 0.05 1 / h. In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of FcRn / antigen binding molecules or FcRn binding molecules in a subject is less than 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.1, 0.09, 0.08, 0.07, 0.06 or 0.05 1 / h. In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the clearance rate of FcRn / antigen binding molecules or FcRn binding molecules is in the range of about 0.05 to about 0.2 1 / h. In some embodiments, after a single administration of the FcRn / antigen binding molecule or the FcRn binding molecule, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is about 0.2, about 0.19, about 0.18, about 0.17, about 0.16, about 0.15, about 0.14, about 0.13, about 0.12, about 0.11, about 0.1, about 0.09, about 0.08, about 0.07, about 0.06 or about 0.05 1 / h. In some embodiments, after a single administration of the FcRn / antigen binding molecule or the FcRn binding molecule, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule is in the range of 0.05 to 0.2 1 / h. In some embodiments, the clearance of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject after a single administration of the FcRn / antigen binding molecule or the FcRn binding molecule is 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.1, 0.09, 0.08, 0.07, 0.06 or 0.05 1 / h.

[0262] In some embodiments, following a single administration of a therapeutically effective amount of the FcRn / antigen binding molecule or the FcRn binding molecule to the subject, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is less than about 2.0, about 1.9, about 1.8, about 1.7, about 1.6, about 1.5, about 1.4, about 1.3, about 1.2, about 1.1, about 1.0, about 0.9, about 0.8, about 0.7, about 0.6, or about 0.5 mL / h / kg.

[0263] In some embodiments, after a single administration of a therapeutically effective amount of the FcRn / antigen binding molecule or the FcRn binding molecule to the subject, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is less than 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6 or 0.5 mL / h / kg.

[0264] In some embodiments, after a single administration of a therapeutically effective amount of the FcRn / antigen binding molecule or the FcRn binding molecule to the subject, the clearance rate of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is about 2.0, about 1.9, about 1.8, about 1.7, about 1.6, about 1.5, about 1.4, about 1.3, about 1.2, about 1.1, about 1.0, about 0.9, about 0.8, about 0.7, about 0.6, or about 0.5 mL / h / kg.

[0265] In some embodiments, after a single administration of a therapeutically effective amount of the FcRn / antigen binding molecule or the FcRn binding molecule to the subject, the clearance of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6 or 0.5 mL / h / kg.

[0266] In some embodiments, after a single therapeutic administration of an FcRn / antigen binding molecule or an FcRn binding molecule, the t of the FcRn / antigen binding molecule or the FcRn binding molecule in a subject is 1 / 2,z Compared with the t of agamod after a single therapeutic administration of agamod 1 / 2,z In some embodiments, after a single therapeutic administration of an FcRn / antigen binding molecule or an FcRn binding molecule, the t of the FcRn / antigen binding molecule or the FcRn binding molecule in the subject is 1 / 2,z Compared with the t of agamod after a single therapeutic administration of agamod 1 / 2,z Compared to an increase of at least 0.5 times, at least 1 times, at least 1.5 times, at least 2 times, at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, at least 10 times, at least 12 times, at least 15 times or at least 20 times.

[0267] In some embodiments, after a single administration of an FcRn / antigen binding molecule or an FcRn binding molecule, the t of the FcRn / antigen binding molecule or the FcRn binding molecule in a subject is 1 / 2,z The t of agamod after a single administration of the same amount of agamod 1 / 2,zIn some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the t of FcRn / antigen binding molecules or FcRn binding molecules in the subject is 1 / 2,z The t of agamod after a single administration of the same amount of agamod 1 / 2,z Compared to an increase of at least 0.5 times, at least 1 times, at least 1.5 times, at least 2 times, at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, at least 10 times, at least 12 times, at least 15 times or at least 20 times.

[0268] In some embodiments, after a single administration of an FcRn / antigen binding molecule or an FcRn binding molecule, the t of the FcRn / antigen binding molecule or the FcRn binding molecule in a subject is 1 / 2,z More than about 3 days, about 3.5 days, about 4 days, about 4.5 days, about 5 days, about 5.5 days, about 6 days, about 6.5 days, about 7 days, about 7.5 days, about 8 days, about 8.5 days, about 9 days, about 9.5 days, about 10 days, about 10.5 days, about 11 days, about 11.5 days, about 12 days, about 12.5 days, about 13 days, about 13.5 days, about 14 days, about 14.5 days, about 15 days, about 15.5 days, about 16 days, about 16.5 days, about 17 days, about 18 days, about 19 days, about 20 days, about 21 days, about 22 days, about 23 days, about 24 days, about 25 days, about 26 days, about 27 days, about 28 days, about 29 days, about 30 days, about 31 days, about 32 days, about 33 days, about 34 days, about 35 days , about 27 days, about 27.5 days, about 28 days, about 28.5 days, about 29 days, about 29.5 days or about 30 days.

[0269] In some embodiments, after a single administration of an FcRn / antigen binding molecule or an FcRn binding molecule, the t of the FcRn / antigen binding molecule or the FcRn binding molecule in a subject is 1 / 2,z More than 3 days, 3.5 days, 4 days, 4.5 days, 5 days, 5.5 days, 6 days, 6.5 days, 7 days, 7.5 days, 8 days, 8.5 days, 9 days, 9.5 days, 10 days, 10.5 days, 11 days, 11.5 days, 12 days, 12.5 days, 13 days, 13.5 days, 14 days, 14.5 days, 15 days, 15.5 days, 16 days, 16.5 days, 17 days , 17.5 days, 18 days, 18.5 days, 19 days, 19.5 days, 20 days, 20.5 days, 21 days, 21.5 days, 22 days, 22.5 days, 23 days, 23.5 days, 24 days, 24.5 days, 25 days, 25.5 days, 26 days, 26.5 days, 27 days, 27.5 days, 28 days, 28.5 days, 29 days, 29.5 days or 30 days.

[0270] In some embodiments, the FcRn / antigen binding molecule or the t of the FcRn binding molecule 1 / 2,z In the range of about 3 days to about 30 days. In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the t of FcRn / antigen binding molecules or FcRn binding molecules in the subject is 1 / 2,z about 3 days, about 3.5 days, about 4 days, about 4.5 days, about 5 days, about 5.5 days, about 6 days, about 6.5 days, about 7 days, about 7.5 days, about 8 days, about 8.5 days, about 9 days, about 9.5 days, about 10 days, about 10.5 days, about 11 days, about 11.5 days, about 12 days, about 12.5 days, about 13 days, about 13.5 days, about 14 days, about 14.5 days, about 15 days, about 15.5 days, about 16 days, about 16.5 days, about 17 days days, about 17.5 days, about 18 days, about 18.5 days, about 19 days, about 19.5 days, about 20 days, about 20.5 days, about 21 days, about 21.5 days, about 22 days, about 22.5 days, about 23 days, about 23.5 days, about 24 days, about 24.5 days, about 25 days, about 25.5 days, about 26 days, about 26.5 days, about 27 days, about 27.5 days, about 28 days, about 28.5 days, about 29 days, about 29.5 days or about 30 days.

[0271] In some embodiments, the FcRn / antigen binding molecule or the t of the FcRn binding molecule 1 / 2,z In the range of 3 days to 30 days. In some embodiments, after a single administration of FcRn / antigen binding molecules or FcRn binding molecules, the t of FcRn / antigen binding molecules or FcRn binding molecules in the subject is 1 / 2,z 3 days, 3.5 days, 4 days, 4.5 days, 5 days, 5.5 days, 6 days, 6.5 days, 7 days, 7.5 days, 8 days, 8.5 days, 9 days, 9.5 days, 10 days, 10.5 days, 11 days, 11.5 days, 12 days, 12.5 days, 13 days, 13.5 days, 14 days, 14.5 days, 15 days, 15.5 days, 16 days, 16.5 days, 17 days , 17.5 days, 18 days, 18.5 days, 19 days, 19.5 days, 20 days, 20.5 days, 21 days, 21.5 days, 22 days, 22.5 days, 23 days, 23.5 days, 24 days, 24.5 days, 25 days, 25.5 days, 26 days, 26.5 days, 27 days, 27.5 days, 28 days, 28.5 days, 29 days, 29.5 days or 30 days.

[0272] In some embodiments, after a single administration of a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule to a subject, the half-life (t 1 / 2) is greater than about 30 hours, about 35 hours, about 40 hours, about 45 hours, about 50 hours, about 55 hours, about 60 hours, about 65 hours, about 70 hours, about 75 hours, about 80 hours, about 85 hours, about 90 hours, about 95 hours or about 100 hours.

[0273] In some embodiments, after a single administration of a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule to a subject, the level of FcRn / antigen binding molecule or an FcRn binding molecule in the subject is 1 / 2 Greater than 30 hours, 35 hours, 40 hours, 45 hours, 50 hours, 55 hours, 60 hours, 65 hours, 70 hours, 75 hours, 80 hours, 85 hours, 90 hours, 95 hours or 100 hours.

[0274] In some embodiments, after a single administration of a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule to a subject, the half-life (t 1 / 2 ) is about 30 hours, about 35 hours, about 40 hours, about 45 hours, about 50 hours, about 55 hours, about 60 hours, about 65 hours, about 70 hours, about 75 hours, about 80 hours, about 85 hours, about 90 hours, about 95 hours or about 100 hours.

[0275] In some embodiments, after a single administration of a therapeutically effective amount of an FcRn / antigen binding molecule or an FcRn binding molecule to a subject, the level of FcRn / antigen binding molecule or an FcRn binding molecule in the subject is 1 / 2 is 30 hours, 35 hours, 40 hours, 45 hours, 50 hours, 55 hours, 60 hours, 65 hours, 70 hours, 75 hours, 80 hours, 85 hours, 90 hours, 95 hours or 100 hours.

[0276] In some embodiments, the single-armed FcRn / antigen binding molecules of the present disclosure are more effective in clearing antigens than double-armed FcRn / antigen binding molecules (such as, for example, full-length antibodies). In some embodiments, the single-armed FcRn / antigen binding molecules are more effective in clearing antigens than the corresponding double-armed FcRn / antigen binding molecules. In other words, in some embodiments, removing one arm of the double-armed FcRn / antigen binding molecule produces a molecule that clears antigens more effectively than the double-armed FcRn / antigen binding molecule.

[0277] As used herein, "clearing" refers to the ability of a molecule to remove an antigen from serum. "Clearing" can be performed by molecules (such as, for example, antibodies) that have at least a threshold level of pH-sensitive antigen binding and binding to FcRn at neutral or physiological pH. For example, a clearing molecule can be bound to an antigen via an antigen binding domain and bound to FcRn via an Fc region, resulting in cellular internalization of an antigen / clearing antibody complex. The antigen can then be released from the complex in the acidic endosome and degraded. In certain embodiments, the clearing molecule that is no longer bound to the antigen can then be released by the cell (for example, by exocytosis) back into the serum.

[0278] In one embodiment, FcRn / antigen binding molecules or FcRn binding molecules are administered to a subject simultaneously or sequentially with another therapeutic agent. In one embodiment, another therapeutic agent is an anti-inflammatory agent. In one embodiment, another therapeutic agent is a corticosteroid. In one embodiment, another therapeutic agent is rituximab, daclizumab, basiliximab, muromonab-CD3, infliximab, adalimumab, omalizumab, efalizumab, natalizumab, tocilizumab, eculizumab, golimumab, canakinumab, ustekinumab or belimumab. In one embodiment, another therapeutic agent is a leukocyte depleting agent.

[0279] In one embodiment, the additional therapeutic agent is a B cell depleting agent. In one embodiment, the B cell depleting agent is an antibody. In one embodiment, the B cell depleting antibody is an antibody that specifically binds to CD10, CD19, CD20, CD21, CD22, CD23, CD24, CD37, CD53, CD70, CD72, CD74, CD75, CD77, CD79a, CD79b, CD80, CD81, CD82, CD83, CD84, CD85, or CD86.

[0280] In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules are administered intravenously. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules are administered intravenously once a week, once every two weeks, once every three weeks, once every four weeks, once a month, or once every six weeks.

[0281] In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules are administered subcutaneously. In some embodiments, the FcRn / antigen binding molecules or FcRn binding molecules are administered subcutaneously once a week, once every two weeks, once every three weeks, once every four weeks, once a month, or once every six weeks.

[0282] Examples

[0283] The following examples are offered by way of illustration and not limitation.

[0284] Example 1: In vitro characterization of OA-Fc-ABDEG molecules

[0285] Preliminary studies have shown that OA-HEL-ABDEG, which contains a Fab fragment that specifically binds to hen egg lysozyme (HEL), attached to Fc-ABDEG at the N-terminus via a native IgG1 hinge, exhibits a 2-fold increase in FcRn occupancy, reaching a level similar to that of agamod (IC50 = 14 nM for TA-HEL-ABDEG; IC50 = 7 nM for OA-HEL-ABDEG; IC50 = 6 nM for agamod). HEL-ABDEG specifically binds to an antigen not found in humans (hen egg lysozyme), and therefore the antigen binding arm of the molecule is not expected to bind to any protein found in humans. It is believed that the improvement in FcRn occupancy after removal of one arm of HEL-ABDEG can be attributed, at least in part, to a reduction in steric hindrance.

[0286] The amino acid sequences of the CDRs of the HEL Fab fragment are as follows: VHCDR1--GYGVN (SEQ ID NO: 18); VHCDR2--MIWGDGNTDYNSALKS (SEQ ID NO: 19); VHCDR3--ERDYRLDY (SEQ ID NO: 20); VLCDR1--RASGNIHNYLA (SEQ ID NO: 21); VLCDR2--YTTTLAD (SEQ ID NO: 22); and VLCDR3--QHFWSTPRT (SEQ ID NO: 23).

[0287] The amino acid sequence of divalent (TA) HEL-ABDEG is:

[0288] HEL-Vk:

[0289] DIQMTQSPSSSLSASVGDRVTITCRASGNIHNYLAWYQQKPGKAPKLLIYYTTTLADGVPSRFSGSGSGTDYTFTISSLQPEDIATYYCQHFWSTPRTFGQGTKVEIKRT VAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC(SEQ IDNO:24)

[0290] HEL-VH:

[0291] QVQLQESGPGLVRPSQTLSLTCTVSGFSLTGYGVNWVRQPPGRGLEWIGMIWGDGNTDYNSALKSRVTMLKDTSKNQFSLRLSSVTAADTAVYYCARERDYRLDYWGQGSLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSC(SEQ ID NO:25)

[0292] HEL-VH-ABDEG:

[0293] QVQLQESGPGLVRPSQTLSLTCTVSGFSLTGYGVNWVRQPPGRGLEWIGMIWGDGNTDYNSALKSRVTMLKDTSKNQFSLRLSSVTAADTAVYYCARERDYRLDYWGQGSLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLYITREPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALKFHYTQKSLSLSPGK(SEQ ID NO:35)

[0294] The amino acid sequence of single-chain (OA) HEL-ABDEG is:

[0295] HEL-Vk:

[0296] DIQMTQSPSSLSASVGDRVTITCRASGNIHNYLAWYQQKPGKAPKLLIYYTTTLADGVPSRFSGSGSGTDYTFTISSLQPEDIATYYCQHFWSTPRTFGQGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC(SEQ ID NO:24)

[0297] HEL-VH:

[0298] QVQLQESGPGLVRPSQTLSLTCTVSGFSLTGYGVNWVRQPPGRGLEWIGMIWGDGNTDYNSALKSRVTMLKDTSKNQFSLRLSSVTAADTAVYYCARERDYRLDYWGQGSLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSC(SEQ ID NO:25)

[0299] HEL-VH-ABDEG-Pestle:

[0300] QVQLQESGPGLVRPSQTLSLTCTVSGFSLTGYGVNWVRQPPGRGLEWIGMIWGDGNTDYNSALKSRVTMLKDTSKNQFSLRLSSVTAADTAVYYCARERDYRLDYWGQGSLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLYITREPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALKFHYTQKSLSLSPG(SEQID NO:34)

[0301] Fc-region-ABDEG:

[0302] DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLYITREPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALKFHYTQKSLSLSPG(SEQ ID NO:8)

[0303] In addition, previous studies have shown that anti-IgE-ABDEG full-length antibody (mAb37) has a lower FcRn occupancy rate (IC50>100nM). mAb37 was previously described in WO / 2020 / 208177, the contents of which are incorporated herein by reference in their entirety. Three mAb37 variant constructs were developed: (1) a single-arm construct (mAb37-OA-ABDEG) with one mAb37 Fab fragment removed, resulting in one Fab fragment remaining at the N-terminus of one of the Fc domains; (2) a double-arm construct in which two mAb37 scFvs are fused to the C-terminus of each Fc domain via a 20GS linker (Fc-ABDEG-mAb37); and (3) a single-arm construct in which one mAb37 scFv is fused to the C-terminus of one Fc domain via a 20GS linker (OA-Fc-ABDEG-mAb37). FcRn occupancy and degradation were measured using an in vitro assay as described elsewhere herein. The results of FcRn occupancy are shown in Table S1 and Figure 1A The results of FcRn degradation are shown in Figure 1B shown.

[0304] Table S1: FcRn occupancy of Fc-ABDEG-mAb37 variants

[0305] name IC50 mAb37-ABDEG (parental) 3748 mAb37-OA-ABDEG 20 Fc-ABDEG-mAb37 6.2 OA-Fc-ABDEG-mAb37 3.9 Agamode 2.0

[0306] The amino acid sequences of the CDRs of mAb37 are as follows: VHCDR1--WHYLE (SEQ ID NO:36); VHCDR2--EIDPGTFTTNYNEKFKA (SEQ ID NO:37); VHCDR3--FSHFSGSNHDYFDY (SEQ ID NO:38); VLCDR1--RASQSIGTNIH (SEQ ID NO:39); VLCDR2--YASESIS (SEQ ID NO:40); and VLCDR3--QQSWSWPTT (SEQ ID NO:41).

[0307] The amino acid sequence of mAb37-OA-ABDEG is:

[0308] mAb37-VL:

[0309] EIVMTQSPATLSVSPGERATLSC RASQSIGTNIH WYQQKPGQAPRLLIY YASESIS GIPARFSGSGSGTEFTLTISSLQSEDFAVYYC QQSWSWPTTFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC(SEQ ID NO:42).

[0310] mAb37-VH:

[0311] QVQLVQSGAEVMKPGSSVKVSCKASGYTFS WYHLE WVRQAPGHCLEWMG EIDPGTFTTNYNEKFKA RVTFTADTSTSTAYMELSSLRSEDTAVYYCAR FSHFSGSNHDYFDY WGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSEIVMTQSPATLSVSPGERATLSC RASQSIGTNIH WYQQKPGQAPRLLIY YASESIS GIPARFSGSGSGTEFTLTISSLQSEDFAVYYC QQSWSWPTT FGCGTKVEIK(SEQ ID NO:43)

[0312] mAb37-VH-ABDEG-pestle:

[0313] QVQLVQSGAEVMKPGSSVKVSCKASGYTFS WYHLE WVRQAPGHGLEWMG EIDPGTFTTNYNEKFKA RVTFTADTSTSTAYMELSSLRSEDTAVYYCAR FSHFSGSNHDYFDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLYITREPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALKFHYTQKSLSLSPG(SEQ ID NO:44)

[0314] Fc-Jiu-ABDEG:

[0315] DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLYITREPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALKFHYTQKSLSLSPG(SEQ ID NO:8)

[0316] The amino acid sequence of OA-Fc-ABDEG-mAb37 is:

[0317] Jiu-ABDEG-mAb37 scFv:

[0318] DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLYITREPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALKFHYTQKSLSLSPGGGGGSGGGGSGGGGSGGGGSQVQLVQSGAEVMKPGSSVKVSCKASGYTFS WYHLE WVRQAPGHCLEWMG E IDPGTFTTNYNEKFKA RVTFTADTSTSTAYMELSSLRSEDTAVYYCAR FSHFSGSNHDYFDY WGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSEIVMTQSPATLSVSPGERATLSC RASQSIGTNIH WYQQKPGQAPRLLIY YASESIS GIPARFSGSGSGTEFTLTISSLQSEDFAVYYC QQSWSWPTT FGCGTKVEIK(SEQ ID NO:45)

[0319] Fc-Jiu-ABDEG:

[0320] DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLYITREPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLVSKLTVDKSRWQQGNVFSCSVMHEALKFHYTQKSLSLSPG(SEQ ID NO:8)

[0321] Example 2: Pharmacokinetics / Pharmacodynamics of OA-HEL-ADBEG in Cynomolgus Monkeys

[0322] The aim of this study was to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) (total IgG) of OA-HEL-ABDEG after a single intravenous (IV) dose of 10, 20 and 85 mg / kg in cynomolgus monkeys. Single dose administration was followed by an 8-week follow-up period.

[0323] The study was conducted in an AAALAC-accredited institution and complies with the provisions of the EU and French animal welfare regulations on the use of animals for experiments (European Directive 2010 / 63 / EU and French decrees and orders No. 2013-118 of February 1, 2013 and No. 2020-274 of March 17, 2020). Briefly, a total of 9 untreated adult male cynomolgus monkeys (2.85-4.25 kg) were randomly assigned to one of three groups (n = 3 per group). Monkeys were given a single dose of IV administration of 10, 20 or 85 mg / kg OA-HEL-ABDEG. Blood samples were collected before (pre-dose) and after treatment for PK, PD and immunogenicity (ADA) evaluation according to the schedule described in Table S2.

[0324] Table S2: Sample collection summary

[0325]

[0326] Pharmacodynamics was assessed by measuring total cynomolgus monkey IgG serum levels using a qualified sandwich ELISA. In short, the plate was coated with mouse anti-monkey IgG antibodies. The capture antibody was bound to the cynomolgus monkey IgG in the standard and sample. After any unbound material in the cleaning plate, an anti-monkey IgG mouse monoclonal antibody labeled with HRP was added to the wells. The plate was then washed and TMB substrate solution was added to the wells. The color development was proportional to the amount of cynomolgus monkey IgG bound in the standard or sample wells. The stop solution was then added to the wells and the plate was read at 450nm (reference 620nm) on the ELISA plate reader.

[0327] The concentration of OA-HEL-ABDEG in monkey serum was determined using a qualified PK assay. In short, anti-HN hFab was coated overnight on a 96-well Maxisorp plate. The next day, the assay plate was washed and then blocked with 1% casein blocking buffer for 1 hour. The research samples, QC samples (2 groups of LQC, MQC and HQC) and calibrators were diluted to an MRD of 10 in assay buffer (PBS+0.1% casein). If necessary, the sample was further diluted in a sample diluent (PBS+0.1% casein+10% mixed cynomolgus monkey serum). 50 μL of research samples, calibrators and QC samples were added to the assay plate in duplicate and incubated for 1 hour. The assay plate was washed and a secondary antibody solution for HN (500 ng / mL in assay buffer) was added for 1 hour. After cleaning the assay plate, 50 μL of detection solution (SA-HRP) was added to the plate for 30 minutes. After washing, TMB substrate was added. After 15 minutes, the color reaction was stopped with sulfuric acid and the OD 450nm was measured on a suitable plate reader (reference 620). The concentration of OA-HEL-ABDEG in the study and QC samples was back-calculated from the calibration curve using Graphpad Prism 8 software using a 5-parameter logistic fit with 1 / Y2 weighting.

[0328] The presence of immune response to OA-HEL-ABDEG was measured by using sandwich ELISA. In short, OA-HEL-ABDEG was coated overnight on ELISA plates and nonspecific binding sites were blocked. A 1:100 dilution of cynomolgus monkey serum in assay buffer was applied before and after administration and incubated for 1 h. The plates were washed and mouse anti-monkey IgG-HRP was added and incubated for 1 h. The plates were developed by adding TMB substrate. The enzymatic reaction was stopped and the optical density value at 450 nm (reference 620 nm) was recorded.

[0329] To evaluate the pharmacodynamic effects of OA-HEL-ABDEG following single IV administration at doses of 10, 20, and 85 mg / kg, total circulating IgG levels in serum samples were determined at baseline (prior to dosing) and post-dose according to the bleeding protocol in Table S2. The baseline IgG concentrations measured on Day -6 and the day of dose administration ranged from 12.2 to 27.4 mg / mL. On average, in Group 1 (10 mg / kg), the IgG concentration decreased to 64% of the pre-dose concentration within a median of 3 days, in Group 2 (20 mg / kg), it decreased to 50% of the pre-dose concentration within a median of 5 days, and in Group 3 (85 mg / kg), it decreased to 39% of the pre-dose concentration within a median of 7 days, resulting in mean IgG reductions of 36%, 50%, and 61% for Groups 1, 2, and 3, respectively. Thereafter, IgG concentrations increased in all groups until the end of the study, reaching 100% to 218% of baseline. Values after Day 8 may have been affected by ADA and were thus considered less reliable. Table S3 provides a summary of the PD data.

[0330] Table S3: Summary of Pharmacodynamic Parameters of OA-HEL-ABDEG in Cynomolgus Monkeys

[0331]

[0332] To evaluate the PK profiles of OA-HEL-ABDEG following single IV administration at doses of 10, 20, and 85 mg / kg, OA-HEL-ABDEG levels in serum samples were determined post-dose according to the bleeding protocol in Table S2. Quantifiable concentrations were detected in most animals up to Day 15 of the study, after which they were below the lower limit of quantification (<LLOQ). Exceptions were one animal in Group 1 that had its last quantifiable concentration measured on Day 29 of the study, one animal from Group 2 that could be quantified until Day 22 of the study, and one animal from Group 3 that had its last quantifiable concentration measured on Day 8 of the study. The OA-HEL-ABDEG serum concentrations obtained were plotted against time over the course of the study ( Figure 2 ). By visual inspection of the pharmacokinetic curves, mean serum OA-HEL-ABDEG increased as the dose increased. For each dose level, the individual curves appeared to be consistent in terms of serum exposure, i.e., low inter-individual variability was observed. After the end of the infusion, in most animals, the concentration first declined rapidly and then more slowly in a second phase, followed by a third phase with a more rapid decline after Day 7. The rapid decline in the third phase could be explained by the presence of anti-drug antibodies (ADA) as all animals in all groups tested positive for ADA on Day 14 and thereafter. Table S4 summarizes the C 最大 , AUC 0-t最后 , t 1 / 2 and CL values.

[0333] Table S4: Summary of pharmacokinetic parameters of OA-HEL-ABDEG in cynomolgus monkeys

[0334]

[0335] After day 7, before ADA testing, a second NCA was performed without obtaining serum concentrations. Adjusted calculations showed that t 1 / 2 Table S5 summarizes the C 最大 , AUC 0-t最后 ,t 1 / 2 and CL adjustment value.

[0336] Table S5: Summary of adjusted pharmacokinetic parameters of OA-HEL-ABDEG in cynomolgus monkeys

[0337]

[0338]

[0339] In conclusion, when the dose was increased from 10 mg / kg to 85 mg / kg, C 最大 Increased in a dose-proportional manner. AUC increased proportionally with dose from 10 mg / kg to 20 mg / kg, but was less than the dose proportional increase from 20 mg / kg to 85 mg / kg. IgG was quantifiable in all animals from one week before dosing to day 56. In Group 1 (10 mg / kg), IgG concentrations decreased to 64% of pre-dose concentrations within a median of 3 days; in Group 2 (20 mg / kg), they decreased to 50% of pre-dose concentrations within a median of 5 days; and in Group 3 (85 mg / kg), they decreased to 39% of pre-dose concentrations within a median of 7 days. Thereafter, IgG concentrations in all groups increased until the end of the study, reaching 100% to 218% of baseline. Values ​​after day 8 of the study may be affected by anti-OA-HEL-ABDEG antibodies (ADA, detected in all groups from day 15) and are therefore considered less reliable.

[0340] ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■

[0341] ***

[0342] The scope of the present invention is not limited by the specific embodiments described herein. In fact, various modifications of the present invention, in addition to the modifications described, will become apparent to those skilled in the art from the foregoing description and the accompanying drawings. Such modifications are intended to fall within the scope of the appended claims.

Claims

1. An FcRn binding molecule comprising a variant Fc region linked to a moiety that does not specifically bind to a human antigen, wherein the variant Fc region binds to FcRn with increased affinity and decreased pH dependence relative to a wild-type Fc region, and wherein the FcRn binding molecule has a molecular weight of between about 50 and about 140 kilodaltons (kDa).

2. The FcRn binding molecule of claim 1, wherein the moiety is not polyethylene glycol.

3. The FcRn binding molecule of claim 1 or 2, wherein the portion is a polypeptide.

4. The FcRn binding molecule according to any one of claims 1 to 3, wherein the portion does not specifically bind to an antigen. The FcRn binding molecule of claim 3 , wherein the polypeptide is an antigen binding domain.

6. The FcRn binding molecule according to any one of claims 1 to 3 or 5, wherein the FcRn binding molecule is an FcRn / antigen binding molecule comprising the variant Fc region and only one antigen binding domain linked to the variant Fc region, wherein the antigen binding domain specifically binds to a non-human antigen.

7. The FcRn binding molecule according to any one of claims 1 to 6, wherein the variant Fc region is a variant IgG Fc region, wherein the variant IgG Fc region comprises or consists of a first Fc domain and a second Fc domain that form a dimer, and wherein the first Fc domain and / or the second Fc domain comprises amino acids Y, T, E, K and F located at EU positions 252, 254, 256, 433 and 434, respectively.

8. The FcRn binding molecule of any one of claims 1 to 7, wherein the FcRn binding molecule has a molecular weight of between about 60 and about 104 kilodaltons (kDa).

9. The FcRn binding molecule according to any one of claims 1 to 8, wherein administration of a therapeutically effective amount of the FcRn binding molecule to a subject results in a decrease in serum IgG in the subject.

10. The FcRn binding molecule of any one of claims 1 to 9, wherein administration of a therapeutically effective amount of the FcRn binding molecule to a subject results in a decrease in serum IgG in the subject by at least about 35%, about 40%, about 50%, about 55%, or about 60% compared to a baseline level of serum IgG in the subject.

11. The FcRn binding molecule according to any one of claims 1 to 10, wherein administration of a therapeutically effective amount of the FcRn binding molecule to a subject does not reduce FcRn and / or albumin levels in the subject.

12. The FcRn binding molecule of any one of claims 1 to 11, wherein the clearance rate of the FcRn binding molecule in the subject is less than about 2, about 1.9, about 1.8, about 1.7, about 1.6, about 1.5, about 1.4, about 1.3, about 1.2, about 1.1, about 1, about 0.9, about 0.8, about 0.7, about 0.6 or about 0.5 mL / h / kg after a single administration of a therapeutically effective amount of the FcRn binding molecule to the subject.

13. The FcRn binding molecule according to any one of claims 1 to 12, wherein the half-life (t 1 / 2 ) is greater than about 30 hours, about 35 hours, about 40 hours, about 45 hours, about 50 hours, about 55 hours, about 60 hours, about 65 hours, about 70 hours, about 75 hours, about 80 hours, about 85 hours, about 90 hours, about 95 hours or about 100 hours.

14. The FcRn binding molecule according to any one of claims 1 to 13, which binds to FcRn at pH 5.5 and / or pH 6.0 with a higher affinity than the affinity of igamod for FcRn at pH 5.5 and / or pH 6.0, optionally as measured by surface plasmon resonance.

15. The FcRn binding molecule according to any one of claims 1 to 13, which binds to FcRn at pH 5.5 and / or pH 6.0 with an affinity lower than the affinity of igamod for FcRn at pH 5.5 and / or pH 6.0, optionally as measured by surface plasmon resonance.

16. The FcRn binding molecule according to any one of claims 6 to 15, wherein the antigen binding domain is selected from the group consisting of a Fab fragment, an sdAb, a scFv and an antibody mimetic.

17. The FcRn binding molecule of claim 16, wherein the antibody mimetic is an anticalin or a DARPin.

18. The FcRn binding molecule of claim 16, wherein the sdAb is a VHH fragment.

19. The FcRn binding molecule according to any one of claims 6 to 18, wherein the non-human antigen is a non-human antigen that can be found in the human body.

20. The FcRn binding molecule of claim 19, wherein the non-human antigen that can be found in the human body is a viral antigen.

21. The FcRn binding molecule according to any one of claims 6 to 18, wherein the non-human antigen is a non-human antigen not found in humans.

22. The FcRn binding molecule of claim 21, wherein the non-human antigen not found in humans is selected from hen egg lysozyme (HEL) or ovalbumin.

23. The FcRn-binding molecule of claim 22, wherein the non-human antigen not found in humans is HEL, and the antigen-binding domain is a Fab fragment or scFv comprising the HCDR1, HCDR2 and HCDR3 amino acid sequences of VH and comprising the LCDR1, LCDR2 and LCDR3 amino acid sequences of VL, wherein the VH comprises the amino acid sequence of SEQ ID NO: 25 and the VL comprises the amino acid sequence of SEQ ID NO:

24.

24. The FcRn binding molecule of claim 22 or 23, wherein the non-human antigen not found in humans is HEL, and the antigen binding domain is a Fab fragment or scFv comprising VH and VL, wherein the VH and VL domains comprise CDR sequences selected from the group consisting of HCDR1 (SEQ ID NO: 18), HCDR2 (SEQ ID NO: 19), HCDR3 (SEQ ID NO: 20), LCDR1 (SEQ ID NO: 21), LCDR2 (SEQ ID NO: 22) and LCDR3 (SEQ ID NO: 23).

25. The FcRn binding molecule of claim 23 or 24, wherein the VH comprises or consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO: 25, and the VL comprises or consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:

24.

26. The FcRn binding molecule according to any one of claims 23 to 25, wherein the VH comprises or consists of the amino acid sequence of SEQ ID NO: 25, and the VL comprises or consists of the amino acid sequence of SEQ ID NO:

24.

27. The FcRn binding molecule of any one of claims 7 to 26, wherein the antigen binding domain is fused to the C-terminus of the first Fc domain or the second Fc domain.

28. The FcRn binding molecule of claim 27, wherein the N-terminus of the antigen binding domain is fused to the C-terminus of the first Fc domain.

29. The FcRn binding molecule of claim 27, wherein the N-terminus of the antigen binding domain is fused to the C-terminus of the second Fc domain.

30. The FcRn binding molecule of any one of claims 7 to 26, wherein the antigen binding domain is fused to the N-terminus of the first Fc domain or the second Fc domain.

31. The FcRn binding molecule of claim 30, wherein the N-terminus of the first Fc domain is fused to the C-terminus of the antigen binding domain.

32. The FcRn binding molecule of claim 30, wherein the N-terminus of the second Fc domain is fused to the C-terminus of the antigen binding domain.

33. The FcRn binding molecule according to any one of claims 7 to 32, wherein the first Fc domain and / or the second Fc domain is an IgG1 Fc domain.

34. The FcRn binding molecule according to any one of claims 7 to 32, wherein the first Fc domain and / or the second Fc domain is a human IgG Fc domain.

35. The FcRn binding molecule according to any one of claims 7 to 34, wherein the first Fc domain and / or the second Fc domain is a human IgG1 Fc domain.

36. The FcRn binding molecule of any one of claims 7 to 35, wherein both the first Fc domain and the second Fc domain comprise amino acids Y, T, E, K and F located at EU positions 252, 254, 256, 433 and 434, respectively.

37. The FcRn binding molecule of any one of claims 7 to 36, wherein the first Fc domain and the second Fc domain are both IgG1 Fc domains.

38. The FcRn binding molecule of any one of claims 7 to 36, wherein the first Fc domain and the second Fc domain are both human IgG Fc domains.

39. The FcRn binding molecule of any one of claims 7 to 38, wherein the first Fc domain and the second Fc domain are both human IgG1 Fc domains.

40. The FcRn binding molecule of any one of claims 7 to 39, wherein the antigen binding domain is fused to the first Fc domain or the second Fc domain via a linker.

41. The FcRn binding molecule of claim 40, wherein the linker is a non-cleavable linker.

42. The FcRn binding molecule of claim 40 or 41, wherein the linker is a peptide linker.

43. The FcRn binding molecule of claim 42, wherein the peptide linker is a GS linker, optionally 8 to 40 amino acids in length, optionally 20 amino acids in length.

44. The FcRn binding molecule according to any one of claims 7 to 42, wherein the antigen binding domain is fused to the first Fc domain or the second Fc domain via an IgG hinge region or a portion thereof.

45. The FcRn binding molecule according to any one of claims 7 to 44, wherein the first Fc domain and / or the second Fc domain comprises an amino acid sequence independently selected from the group consisting of the amino acid sequences shown in SEQ ID NOs: 1, 2 and 3.

46. ​​The FcRn binding molecule of claim 45, wherein the first Fc domain and / or the second Fc domain comprises the amino acid sequence of SEQ ID NO:

2.

47. The FcRn binding molecule of claim 45, wherein both the first Fc domain and the second Fc domain comprise an amino acid sequence independently selected from the group consisting of the amino acid sequences shown in SEQ ID NOs: 1, 2, and 3.

48. The FcRn binding molecule of claim 47, wherein both the first Fc domain and the second Fc domain comprise the amino acid sequence of SEQ ID NO:

2.

49. The FcRn binding molecule according to any one of claims 7 to 45, wherein the amino acid sequence of each of the first Fc domain and the second Fc domain consists of an amino acid sequence independently selected from the group consisting of: The amino acid sequences shown in SEQ ID NOs: 1, 2 and 3.

50. The FcRn binding molecule of claim 49, wherein the amino acid sequence of the first Fc domain or the amino acid sequence of the second Fc domain consists of SEQ ID NO:

2.

51. The FcRn binding molecule of claim 50, wherein the amino acid sequences of both the first Fc domain and the second Fc domain consist of SEQ ID NO:

2.

52. The FcRn binding molecule of any one of claims 7 to 44, wherein the amino acid sequence of the first Fc domain further comprises amino acid W at EU position 366.

53. The FcRn binding molecule of claim 52, wherein the amino acid sequence of the first Fc domain comprises an amino acid sequence selected from the group consisting of the amino acid sequences shown in SEQ ID NOs: 4, 5 and 6.

54. The FcRn binding molecule of claim 53, wherein the amino acid sequence of the first Fc domain comprises the amino acid sequence of SEQ ID NO:

5.

55. The FcRn binding molecule of claim 53, wherein the amino acid sequence of the first Fc domain consists of an amino acid sequence selected from the group consisting of: The amino acid sequences shown in SEQ ID NOs: 4, 5 and 6.

56. The FcRn binding molecule of claim 55, wherein the amino acid sequence of the first Fc domain consists of the amino acid sequence of SEQ ID NO:

5.

57. The FcRn binding molecule of any one of claims 7 to 44 and 52 to 56, wherein the amino acid sequence of the second Fc domain further comprises amino acids S, A and V at EU positions 366, 368 and 407, respectively.

58. The FcRn binding molecule of claim 57, wherein the amino acid sequence of the second Fc domain comprises an amino acid sequence selected from the group consisting of the amino acid sequences shown in SEQ ID NOs: 7, 8 and 9.

59. The FcRn binding molecule of claim 58, wherein the amino acid sequence of the second Fc domain comprises the amino acid sequence of SEQ ID NO:

8.

60. The FcRn binding molecule of claim 58, wherein the amino acid sequence of the second Fc domain consists of an amino acid sequence selected from the group consisting of: The amino acid sequences shown in SEQ ID NOs:7, 8 and 9.

61. The FcRn binding molecule of claim 60, wherein the amino acid sequence of the second Fc domain consists of the amino acid sequence of SEQ ID NO:

8.

62. An FcRn / antigen binding molecule comprising a first heavy chain, wherein the first heavy chain comprises or consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:

34.

63. The FcRn / antigen binding molecule of claim 62, wherein the first heavy chain comprises or consists of the amino acid sequence of SEQ ID NO:

34.

64. The FcRn / antigen binding molecule of claim 62 or 63, further comprising a second heavy chain, wherein the second heavy chain consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:

8.

65. The FcRn / antigen binding molecule of claim 64, wherein the second heavy chain consists of the amino acid sequence of SEQ ID NO:

8.

66. The FcRn / antigen binding molecule of any one of claims 62 to 65, further comprising a light chain, wherein the light chain comprises or consists of an amino acid sequence that is at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:

24.

67. The FcRn / antigen binding molecule of claim 66, wherein the light chain comprises or consists of the amino acid sequence of SEQ ID NO:

24.

68. One or more isolated polynucleotides encoding the FcRn binding molecule according to any one of claims 1 to 61 or the FcRn / antigen binding molecule according to any one of claims 62 to 67.

69. An expression vector comprising one or more isolated polynucleotides according to claim 68.

70. A host cell comprising one or more isolated polynucleotides according to claim 68 or an expression vector according to claim 69.

71. A method for producing an FcRn binding molecule or an FcRn / antigen binding molecule, the method comprising culturing the host cell according to claim 70 under conditions that allow expression of the FcRn binding molecule or the FcRn / antigen binding molecule.

72. A pharmaceutical composition comprising the FcRn binding molecule according to any one of claims 1 to 61, or the FcRn / antigen binding molecule according to any one of claims 62 to 67, and at least one pharmaceutically acceptable carrier.

73. The FcRn binding molecule according to any one of claims 1 to 61, or the FcRn / antigen binding molecule according to any one of claims 62 to 77, or the pharmaceutical composition according to claim 72, for use as a medicament.

74. A method of reducing serum IgG in a subject, the method comprising administering to a patient in need thereof a therapeutically effective amount of the FcRn binding molecule of any one of claims 1 to 61, or the FcRn / antigen binding molecule of any one of claims 62 to 67, or the pharmaceutical composition of claim 72.

75. A method of treating an antibody-mediated disorder in a subject, the method comprising administering to a patient in need thereof a therapeutically effective amount of the FcRn binding molecule of any one of claims 1 to 61, or the FcRn / antigen binding molecule of any one of claims 62 to 67, or the pharmaceutical composition of claim 72.

76. The method of claim 75, wherein the antibody-mediated disorder is an IgG-mediated disorder.

77. The method of claim 75 or 76, wherein the antibody-mediated disorder is an autoimmune disease.

78. The method of claim 77, wherein the autoimmune disease is selected from the group consisting of: allogeneic islet transplant rejection, alopecia areata, ankylosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, Alzheimer's disease, antineutrophil cytoplasmic autoantibodies (ANCA), adrenal autoimmune disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune myocarditis, autoimmune neutropenia, autoimmune oophoritis and orchitis, immune thrombocytopenia (ITP or idiopathic thrombocytopenic purpura, idiopathic thrombocytopenic purpura, immune-mediated thrombocytopenia or primary immune thrombocytopenia), autoimmune urticaria, Behcet's disease, bullous pemphigoid (BP), cardiomyopathy, Castleman syndrome, celiac sprue, chronic fatigue immune dysfunction syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP), Chargar-Strauss syndrome, cicatricial pemphigoid, CREST syndrome, cold agglutinin disease, Crohn's disease, dilated cardiomyopathy, discoid lupus, epidermolysis bullosa acquisita, essential mixed cryoglobulinemia, factor VIII deficiency, fibromyalgia-fibromyositis, glomerulonephritis, Graves' disease, Guillain-Barré syndrome, Goodpasture's syndrome, graft-versus-host disease (GVHD), Hashimoto's thyroiditis, hemophilia A, idiopathic inflammatory myopathy (IIM), idiopathic membrane Neuropathy, idiopathic pulmonary fibrosis, IgA neuropathy, IgM polyneuropathy, immune-mediated necrotizing myopathy (IMNM), juvenile arthritis, Kawasaki disease, lichen planus, atrophic lichen sclerosus, lupus erythematosus, lupus nephritis, Meniere's disease, mixed connective tissue disease, mucous membrane pemphigoid, multiple sclerosis, type 1 diabetes, multifocal motor neuropathy (MMN), myasthenia gravis (MG), generalized myasthenia gravis (gMG), myositis, paraneoplastic bullous pemphigoid, pemphigoid gestationis, pemphigus vulgaris (PV), pemphigus foliaceus (PF), pernicious anemia, polyarteritis nodosa, polychondritis, polyglandular syndrome, polymyalgia rheumatica, polymyositis, dermatomyositis (D M), necrotizing autoimmune myopathy (NAM), antisynthetase syndrome (ASyS), primary agammaglobulinemia, primary biliary cirrhosis, psoriasis, psoriatic arthritis, relapsing polychondritis, Raynaud's phenomenon, Reiter syndrome, rheumatoid arthritis, sarcoidosis, scleroderma, Sjögren's syndrome, solid organ transplant rejection, stiff-person syndrome, systemic lupus erythematosus, Takayasu arteritis, toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), temporal arteritis / giant cell arteritis, thrombotic thrombocytopenic purpura, ulcerative colitis, uveitis, dermatitis herpetiformis, vasculitis, antineutrophil cytoplasmic antibody-associated vasculitis, vitiligo, and Wegener's granulomatosis.

79. The method of any one of claims 74 to 78, wherein the FcRn binding molecule or FcRn / antigen binding molecule is administered to the subject simultaneously or sequentially with an additional therapeutic agent.

80. The FcRn binding molecule according to any one of claims 1 to 61, or the FcRn / antigen binding molecule according to any one of claims 62 to 67, or the pharmaceutical composition according to claim 72, for use in the treatment of an antibody-mediated disorder.

81. An FcRn binding molecule according to any one of claims 1 to 61 or an FcRn / antigen binding molecule according to any one of claims 62 to 67 for use in the manufacture of a medicament for the treatment of an antibody-mediated disorder.

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