Anti-FXI / fxia antibody and use thereof

Abstract

To provide an anti-FXI antibody and / or an anti-FXIa antibody with higher specificity, lower toxic and side effects, better clinical efficacy, and more convenient administration methods.SOLUTION: An anti-FXI / FXIa antibody or an antigen-binding fragment thereof described herein has specificity and high affinity to FXI / FXIa, and can effectively inhibit the activity of FXI / FXIa. Accordingly, the present invention further provides a pharmaceutical composition comprising the antibody or the antigen-binding fragment thereof, and a use thereof in the preparation of a drug for the prevention and / or treatment of diseases or disorders related to coagulation or thromboembolism.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to the field of therapeutic monoclonal antibodies. More particularly, the present invention relates to antibodies against FXI and / or FXIa, and to the use of antibodies for the prevention and / or treatment of diseases or disorders associated with coagulation or thromboembolism.

Background Art

[0002] Thrombosis or embolism is associated with diseases of various organs throughout the body, mainly heart disease, brain disease, and peripheral vascular disease. Thrombosis or embolism has a high incidence, a high degree of physical dysfunction, and a lethal characteristic, and is the leading cause of death caused by cardiovascular disease. Currently, prophylactic and therapeutic drugs for thrombotic diseases mainly include three types, namely, anticoagulants, antiplatelet drugs, and thrombolytic drugs. Anticoagulants are mainly used to prevent and treat venous thromboembolism caused by various reasons, and can also be used for the prevention of stroke in patients with atrial fibrillation and for anticoagulant therapy in patients with acute coronary syndrome. There is a large market demand for anticoagulants, and there are drugs available for clinical use. However, currently clinically used anticoagulants mainly inhibit the general coagulation cascade pathway, and thus bleeding is a major complication. Conventional anticoagulants such as warfarin, heparin, low-molecular-weight heparin, etc., and new drugs that have emerged on the market in recent years, such as FXa inhibitors (rivaroxaban, apixaban, etc.) and thrombin inhibitors (dabigatran etexilate, hirudin, etc.), all have a good effect on reducing thrombosis, but all face a common drawback, that is, they can cause bleeding complications. Therefore, there is an urgent clinical need for anticoagulants with a low risk of bleeding.

[0003] Factor XI (FXI) participates in the intrinsic coagulation cascade, and its active form is Factor XIa (FXIa). The FXI protein is a dimer formed by two identical monomers with a molecular weight of approximately 80 kDa via disulfide bonds. The monomer of FXI consists of four apple domains and one catalytic domain, which is catalyzed by Factor XIIa (FXIIa) to form FXIa with an exposed binding site to FIX. This binds to FIX and then promotes the conversion of FIX to active FIXa, thereby activating the downstream coagulation cascade. Factor XI is a glycoprotein in the form of zymogen in mammalian plasma, with a concentration of approximately 25 - 30 nM. Almost all FXI forms a complex with high molecular weight kininogen (HK) and circulates in the blood. So far, the effect of HK on FXI function remains unclear. HK may assist FXI in binding to the surface of platelets or endothelial cells, and it has also been observed that HK inhibits the activation of FXI. The activation process of FXI involves cleavage of each monomer between Arg369 and Ile370 under the action of different proteases, resulting in a protein consisting of a heavy chain of approximately 50 kDa containing the apple domain and a light chain of approximately 30 kDa containing the catalytic domain. The heavy chain and the light chain are connected by a disulfide bond formed between Cys362 and Cys482. Activated FXI, i.e., FXIa, usually refers to the case where each monomer of dimeric FXI is cleaved at Arg369, but only one monomer is activated. FXIa 2+ cleaves FIX with the participation of Ca, converting it to activated FIX (FIXa), which then converts Factor X to its active form, Xa. Then, Xa can mediate the activation of Factor II / thrombin. Thrombin, as the last protease in the coagulation cascade, can further promote the production of FXIa by directly activating FXI via a feedback mechanism. Both Factor XIIa and FXIa (autoactivation) in the coagulation cascade convert FXI to FXIa.

[0004] In addition, activated FIX (FIXa) can directly bind to platelets, promote the formation of platelet aggregates in blood, and form occlusion of distal microvessels. Therefore, FIX / FIXa promotes thrombosis through various ways. Furthermore, animal experiments and clinical observations indicate that the risk of bleeding remains minimal even in the absence of FIX / FIXa. Therefore, FIX / FIXa is an ideal target for preventing and treating diseases / disorders associated with coagulation or thromboembolism (Zilberman-Rudenko J. et al., "Coagulation factor XI promotes distal platelet activation and single platelet connsumpation in the bloodstream under shear flow", Arterioscler Thromb Vasc Biol., March 2016, 36(3):510-517). Factors that regulate coagulation function through the intervention of FXI molecules and / or FXIa molecules include, but are not limited to, the formation of FXI and / or FXIa dimers; blocking the contact between molecules that can activate FXI (e.g., factor XIIa, FXIa) and FXI, thereby inhibiting or blocking the activation of FXI; inhibiting or blocking the formation of the complex between FXI and HK; closing the catalytic domain of FXI and / or FXIa or inducing conformational changes in the catalytic domain, thereby inactivating FXI and / or FXIa, and thereby inhibiting or preventing the activation of the intrinsic coagulation pathway; inhibiting or blocking the binding of FXI and / or FXIa to its substrate.

[0005] Currently, Bayer's FXIa antibody drug, BAY-1213790, is under a Phase II clinical trial for the indication of venous thrombosis. BAY-1213790 is derived from a phage display library and binds to the FXIa catalytic domain. In addition, Aronora's AB-023 (14E11) is in Phase I clinical trials for the indication of venous thrombosis and in Phase II clinical trials for the indication of end-stage renal disease (ESRD). SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

[0006] At present, FXIa-targeting antibody drugs are not on the market. Therefore, it is urgently necessary to develop anti-FXI antibodies and / or anti-FXIa antibodies with high specificity, low toxicity and side effects, good clinical efficacy, and a more convenient administration method, which will provide more dosing options for patients.

Means for Solving the Problems

[0007] In this application, the inventors first developed mouse antibodies with excellent properties that can specifically recognize FXI and / or FXIa. Based on this, the inventors deepened the research on the mouse antibodies and made great creative efforts to perform modifications on them, thereby developing their humanized antibodies.

[0008] The antibodies (especially humanized antibodies) of the present invention that retain (or improve) the functions and properties of the parental mouse antibodies, such as the functions and properties of binding to FXI and / or FXIa with high affinity and specificity, and thus have the potential to be used for the prevention and treatment of coagulation disorders or thromboembolic disorders, and also have a very high degree of humanization and can be safely administered to human subjects without inducing an immunogenic reaction, are extremely advantageous. Therefore, the antibodies of the present invention have great clinical value.

Brief Description of the Drawings

[0009]

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Mode for Carrying Out the Invention

[0010] The antibody of the present invention In one aspect, the present invention is an antibody or an antigen-binding fragment thereof that can specifically bind to FXI and / or FXIa, and has the following: (a) Three heavy-chain CDRs as follows: CDR-H1, CDR-H2, and CDR-H3 contained in the heavy-chain variable region (VH) shown in any one of SEQ ID NOs: 1, 15, 16, 17, 29, 31; and / or Three light-chain CDRs as follows: CDR-L1, CDR-L2, and CDR-L3 contained in the light-chain variable region (VL) shown in any one of SEQ ID NOs: 2, 18, 19, 20, 30, 32; Or (b) Three heavy-chain CDRs as follows: CDR-H1 described in (a), or a variant containing an amino acid mutation compared thereto, CDR-H2 described in (a), or a variant containing an amino acid mutation compared thereto, CDR-H3 described in (a), or a variant containing an amino acid mutation compared thereto; and / or Three light chain CDRs as follows: CDR-L1 described in (a), or a variant containing amino acid mutations compared thereto; CDR-L2 described in (a), or a variant containing amino acid mutations compared thereto; CDR-L3 described in (a), or a variant containing amino acid mutations compared thereto comprising (b) at least one CDR of the three heavy chain CDRs and / or three light chain CDRs described in (b) contains an amino acid mutation compared to the corresponding CDR in (a), and the amino acid mutation is a substitution, deletion, or addition of one or several amino acids (e.g., substitution, deletion, or addition of one, two, or three amino acids) providing an antibody or an antigen-binding fragment thereof

[0011] In certain preferred embodiments, the substitution is a conservative substitution

[0012] In certain preferred embodiments, the CDRs of the antibody or its antigen-binding fragment are defined according to the numbering system by Kabat, IMGT, Chothia, or AbM

[0013] In certain preferred embodiments, the antibody or its antigen-binding fragment further comprises a framework region (FR) of an immunoglobulin derived from human or mouse

[0014] In certain preferred embodiments, the antibody or its antigen-binding fragment binds to human FXI and / or human FXIa

[0015] In certain embodiments, the antibody or its antigen-binding fragment (a) Three heavy chain CDRs as follows: CDR-H1, CDR-H2, and CDR-H3 contained in the heavy chain variable region (VH) shown in any one of SEQ ID NOs: 1, 15, 16, 17; and / or Any one of the following three light chain CDRs: CDR-L1, CDR-L2, and CDR-L3 contained in the light chain variable region (VL) shown in any one of SEQ ID NOs: 2, 18, 19, 20; or (b) Any one of the following three heavy chain CDRs: CDR-H1 described in (a), or a variant containing an amino acid mutation compared thereto, CDR-H2 described in (a), or a variant containing an amino acid mutation compared thereto, CDR-H3 described in (a), or a variant containing an amino acid mutation compared thereto; and / or Any one of the following three light chain CDRs: CDR-L1 described in (a), or a variant containing an amino acid mutation compared thereto, CDR-L2 described in (a), or a variant containing an amino acid mutation compared thereto, CDR-L3 described in (a), or a variant containing an amino acid mutation compared thereto comprising At least one CDR of the three heavy chain CDRs and / or three light chain CDRs described in (b) contains an amino acid mutation compared to the corresponding CDR in (a), and the amino acid mutation is a substitution, deletion, or addition of one or several amino acids (e.g., substitution, deletion, or addition of one, two, or three amino acids); in certain preferred embodiments, the substitution is a conservative substitution.

[0016] In certain embodiments, the antibody or antigen-binding fragment thereof is (a) Any one of the following three heavy chain CDRs: CDR-H1, CDR-H2, and CDR-H3 contained in the heavy chain variable region (VH) shown in any one of SEQ ID NOs: 29, 31; and / or Any one of the following three light chain CDRs: CDR-L1, CDR-L2, and CDR-L3 contained in the light chain variable region (VL) shown in any one of SEQ ID NOs: 30, 32; or (b) The following three heavy-chain CDRs: CDR-H1 described in (a), or a variant containing amino acid mutations compared thereto; CDR-H2 described in (a), or a variant containing amino acid mutations compared thereto; CDR-H3 described in (a), or a variant containing amino acid mutations compared thereto; and / or The following three light-chain CDRs: CDR-L1 described in (a), or a variant containing amino acid mutations compared thereto; CDR-L2 described in (a), or a variant containing amino acid mutations compared thereto; CDR-L3 described in (a), or a variant containing amino acid mutations compared thereto comprising At least one of the three heavy-chain CDRs and / or three light-chain CDRs described in (b) contains amino acid mutations compared to the corresponding CDR in (a), and the amino acid mutations are substitutions, deletions, or additions of one or several amino acids (e.g., substitutions, deletions, or additions of one, two, or three amino acids); in certain preferred embodiments, the substitutions are conservative substitutions.

[0017] In certain embodiments, the antibody or its antigen-binding fragment comprises a heavy-chain variable region (VH) and / or a light-chain variable region (VL).

[0018] In certain embodiments, the antibody or its antigen-binding fragment according to the present invention has a heavy-chain variable region (VH) and / or a light-chain variable region (VL) with CDRs as follows, defined by the numbering system of IMGT: (a) A heavy-chain variable region (VH) comprising the following three CDRs: CDR-H1 with the sequence of SEQ ID NO: 3, CDR-H2 with the sequence of SEQ ID NO: 4, and CDR-H3 with the sequence of SEQ ID NO: 5; and / or A light-chain variable region (VL) comprising the following three CDRs: CDR-L1 with the sequence of SEQ ID NO: 6, CDR-L2 with the sequence of SEQ ID NO: 7, and CDR-L3 with the sequence of SEQ ID NO: 8; or (b) A heavy chain variable region (VH) comprising the following three CDRs: CDR-H1 with the sequence of SEQ ID NO: 33, CDR-H2 with the sequence of SEQ ID NO: 34, and CDR-H3 with the sequence of SEQ ID NO: 35; and / or A light chain variable region (VL) comprising the following three CDRs: CDR-L1 with the sequence of SEQ ID NO: 36, CDR-L2 with the sequence of SEQ ID NO: 37, and CDR-L3 with the sequence of SEQ ID NO: 38 is included.

[0019] In certain embodiments, an antibody or antigen-binding fragment thereof according to the present invention comprises a heavy chain variable region (VH) and / or a light chain variable region (VL), wherein at least one CDR of the heavy chain variable region (VH) and / or the light chain variable region (VL) comprises an amino acid mutation as compared to the heavy chain variable region and / or the light chain variable region described in (a) or (b) under the definition by IMGT, and the amino acid mutation is a substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., a substitution, deletion, or addition of one, two, or three amino acids, or any combination thereof); preferably, the substitution is a conservative substitution.

[0020] In certain embodiments, an antibody or antigen-binding fragment thereof according to the present invention has a heavy chain variable region (VH) and / or a light chain variable region (VL) wherein the CDRs are defined by the numbering system of AbM as follows: (a) A heavy chain variable region (VH) comprising the following three CDRs: CDR-H1 with the sequence of SEQ ID NO: 9, CDR-H2 with the sequence of SEQ ID NO: 10, and CDR-H3 with the sequence of SEQ ID NO: 11; and / or A light chain variable region (VL) comprising the following three CDRs: CDR-L1 with the sequence of SEQ ID NO: 12, CDR-L2 with the sequence of SEQ ID NO: 13, and CDR-L3 with the sequence of SEQ ID NO: 14; or (b) The following three CDRs: a heavy chain variable region (VH) comprising CDR-H1 with the sequence of SEQ ID NO: 39, CDR-H2 with the sequence of SEQ ID NO: 40, and CDR-H3 with the sequence of SEQ ID NO: 41; and / or The following three CDRs: a light chain variable region (VL) comprising CDR-L1 with the sequence of SEQ ID NO: 42, CDR-L2 with the sequence of SEQ ID NO: 43, and CDR-L3 with the sequence of SEQ ID NO: 44 are included.

[0021] In certain embodiments, an antibody or antigen-binding fragment thereof according to the invention comprises a heavy chain variable region (VH) and / or a light chain variable region (VL), wherein at least one CDR of the heavy chain variable region (VH) and / or the light chain variable region (VL) comprises an amino acid variation as compared to the heavy chain variable region and / or the light chain variable region described in (a) or (b) under the definition by AbM, the amino acid variation being a substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, or three amino acids, or any combination thereof); preferably, the substitution is a conservative substitution.

[0022] In certain embodiments, an antibody or antigen-binding fragment thereof according to the invention comprises a heavy chain variable region (VH) and / or a light chain variable region (VL), wherein at least one CDR of the heavy chain variable region (VH) and / or the light chain variable region (VL) comprises an amino acid variation as compared to the heavy chain variable region and / or the light chain variable region described in (a) or (b) under the definition by IMGT or AbM, the amino acid variation being a substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, or three amino acids, or any combination thereof); preferably, the substitution is a conservative substitution.

[0023] In certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention has a VH comprising a framework region (FR) of the heavy chain variable region (VH) derived from murine immunoglobulins; and / or the antibody or antigen-binding fragment thereof has a VL comprising a framework region (FR) of the light chain variable region (VL) derived from murine immunoglobulins. Thus, in certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention is derived from murine immunoglobulins.

[0024] In certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention has a VH comprising a framework region (FR) of the heavy chain variable region (VH) derived from human immunoglobulins; and / or the antibody or antigen-binding fragment thereof has a VL comprising a framework region (FR) of the light chain variable region (VL) derived from human immunoglobulins. Thus, in certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention is humanized. In such embodiments, the FR of the heavy chain variable region and / or the FR of the light chain variable region of the antibody or antigen-binding fragment thereof according to the present invention may comprise one or more non-human (e.g., murine) amino acid residues. For example, the FR that is the heavy chain framework region and / or the FR that is the light chain framework region can contain one or more amino acid back mutations, and these back mutations contain the corresponding murine amino acid residues.

[0025] In certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention (a) a human immunoglobulin heavy chain framework region, or a variant thereof, having up to 20 conservative substitutions of amino acids (e.g., up to 15, up to 10, up to 5 amino acid conservative substitutions; e.g., 1, 2, 3, 4, or 5 amino acid conservative substitutions) compared to the germline antibody gene sequence from which it is derived; and / or (b) a human immunoglobulin light chain framework region, or a variant thereof, having up to 20 conservative substitutions of amino acids (e.g., up to 15, up to 10, up to 5 conservative substitutions of amino acids; e.g., 1, 2, 3, 4, or 5 conservative substitutions of amino acids) compared to the antibody gene sequence of the germ line from which it is derived comprising.

[0026] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention has a humanization degree of at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100%.

[0027] In certain embodiments, the antibody or antigen-binding fragment thereof according to the present invention (a) a heavy chain variable region (VH) comprising an amino acid sequence selected from the following: (i) the sequence shown in any one of SEQ ID NOs: 1, 15, 16, 17; (ii) a sequence having one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., 1, 2, 3, 4, or 5 amino acid substitutions, deletions, or additions, or any combination thereof) compared to the sequence shown in any one of SEQ ID NOs: 1, 15, 16, 17; or (iii) a sequence having at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the sequence shown in any one of SEQ ID NOs: 1, 15, 16, 17; and / or (b) a light chain variable region (VL) comprising an amino acid sequence selected from the following: (iv) The sequence shown in any one of SEQ ID NO: 2, 18, 19, or 20; (v) A sequence having a substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the sequence shown in any one of SEQ ID NO: 2, 18, 19, or 20; or (vi) A sequence having at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the sequence shown in any one of SEQ ID NO: 2, 18, 19, or 20 and includes.

[0028] In certain embodiments, the antibody or antigen-binding fragment thereof according to the present invention (a) A heavy chain variable region (VH) comprising an amino acid sequence selected from: (i) The sequence shown in any one of SEQ ID NO: 29 or 31; (ii) A sequence having a substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the sequence shown in any one of SEQ ID NO: 29 or 31; or (iii) A sequence having at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the sequence shown in any one of SEQ ID NO: 29 or 31; and / or (b) A light chain variable region (VL) comprising an amino acid sequence selected from: (iv) The sequence shown in any one of SEQ ID NOs: 30 and 32; (v) A sequence having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) as compared with the sequence shown in any one of SEQ ID NOs: 30 and 32; or (vi) A sequence having at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the sequence shown in any one of SEQ ID NOs: 30 and 32 is included.

[0029] In certain embodiments, the antibody or antigen-binding fragment thereof according to the present invention has a heavy chain variable region (VH) and / or a light chain variable region (VL) as follows: VH shown in any one of SEQ ID NOs: 1, 15, 16, 17, and / or VL shown in any one of SEQ ID NOs: 2, 18, 19, 20.

[0030] In certain embodiments, the antibody or antigen-binding fragment thereof according to the present invention has a heavy chain variable region (VH) and / or a light chain variable region (VL) as follows: VH shown in any one of SEQ ID NOs: 29, 31, and / or VL shown in any one of SEQ ID NOs: 30, 32.

[0031] In certain embodiments, the antibody or antigen-binding fragment thereof according to the present invention comprises VH shown in SEQ ID NO: 1 and / or VL shown in SEQ ID NO: 2.

[0032] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof according to the invention has at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity compared to the VH shown in SEQ ID NO: 1 and / or the VL shown in SEQ ID NO: 2.

[0033] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof has one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the VH shown in SEQ ID NO: 1 and / or the VL shown in SEQ ID NO: 2. In preferred embodiments, the substitutions are conservative substitutions.

[0034] In certain embodiments, an antibody or antigen-binding fragment thereof according to the invention comprises the VH shown in SEQ ID NO: 15 and / or the VL shown in SEQ ID NO: 18.

[0035] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof according to the invention has at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity compared to the VH shown in SEQ ID NO: 15 and / or the VL shown in SEQ ID NO: 18.

[0036] In certain embodiments, the VH and / or VL of the antibody or antigen-binding fragment thereof have one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the VH shown in SEQ ID NO: 15 and / or the VL shown in SEQ ID NO: 18. In preferred embodiments, the substitutions are conservative substitutions.

[0037] In certain embodiments, the antibody or antigen-binding fragment thereof according to the present invention comprises the VH shown in SEQ ID NO: 15 and / or the VL shown in SEQ ID NO: 20.

[0038] In certain embodiments, the VH and / or VL of the antibody or antigen-binding fragment thereof according to the present invention have at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity compared to the VH shown in SEQ ID NO: 15 and / or the VL shown in SEQ ID NO: 20.

[0039] In certain embodiments, the VH and / or VL of the antibody or antigen-binding fragment thereof have one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the VH shown in SEQ ID NO: 15 and / or the VL shown in SEQ ID NO: 20. In preferred embodiments, the substitutions are conservative substitutions.

[0040] In certain embodiments, the antibody or antigen-binding fragment thereof according to the present invention comprises the VH shown in SEQ ID NO: 16 and / or the VL shown in SEQ ID NO: 18.

[0041] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof according to the invention has at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity compared to the VH shown in SEQ ID NO: 16 and / or the VL shown in SEQ ID NO: 18.

[0042] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof has one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof) compared to the VH shown in SEQ ID NO: 16 and / or the VL shown in SEQ ID NO: 18. In preferred embodiments, the substitutions are conservative substitutions.

[0043] In certain embodiments, an antibody or antigen-binding fragment thereof according to the invention comprises the VH shown in SEQ ID NO: 17 and / or the VL shown in SEQ ID NO: 19.

[0044] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof according to the invention has at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity compared to the VH shown in SEQ ID NO: 17 and / or the VL shown in SEQ ID NO: 19.

[0045] In certain embodiments, the VH and / or VL of an antibody or an antigen-binding fragment thereof has one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) as compared to the VH shown in SEQ ID NO: 17 and / or the VL shown in SEQ ID NO: 19. In preferred embodiments, the substitutions are conservative substitutions.

[0046] In certain embodiments, an antibody or an antigen-binding fragment thereof according to the present invention comprises the VH shown in SEQ ID NO: 17 and / or the VL shown in SEQ ID NO: 18.

[0047] In certain embodiments, the VH and / or VL of an antibody or an antigen-binding fragment thereof according to the present invention has at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity as compared to the VH shown in SEQ ID NO: 17 and / or the VL shown in SEQ ID NO: 18.

[0048] In certain embodiments, the VH and / or VL of an antibody or an antigen-binding fragment thereof has one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) as compared to the VH shown in SEQ ID NO: 17 and / or the VL shown in SEQ ID NO: 18. In preferred embodiments, the substitutions are conservative substitutions.

[0049] In certain embodiments, an antibody or an antigen-binding fragment thereof according to the present invention comprises the VH shown in SEQ ID NO: 29 and / or the VL shown in SEQ ID NO: 30.

[0050] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof according to the present invention have at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity compared to the VH shown in SEQ ID NO: 29 and / or the VL shown in SEQ ID NO: 30.

[0051] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof have one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the VH shown in SEQ ID NO: 29 and / or the VL shown in SEQ ID NO: 30. In preferred embodiments, the substitutions are conservative substitutions.

[0052] In certain embodiments, an antibody or antigen-binding fragment thereof according to the present invention comprises the VH shown in SEQ ID NO: 31 and / or the VL shown in SEQ ID NO: 32.

[0053] In certain embodiments, the VH and / or VL of an antibody or antigen-binding fragment thereof according to the present invention have at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity compared to the VH shown in SEQ ID NO: 31 and / or the VL shown in SEQ ID NO: 32.

[0054] In certain embodiments, the VH and / or VL of an antibody or an antigen-binding fragment thereof has one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) as compared to the VH shown in SEQ ID NO: 31 and / or the VL shown in SEQ ID NO: 32. In preferred embodiments, the substitutions are conservative substitutions.

[0055] In certain preferred embodiments, the antibody or an antigen-binding fragment thereof according to the present invention (a) has a VH having the sequence shown in SEQ ID NO: 1 and a VL having the sequence shown in SEQ ID NO: 2; (b) has a VH having the sequence shown in SEQ ID NO: 15 and a VL having the sequence shown in SEQ ID NO: 18; (c) has a VH having the sequence shown in SEQ ID NO: 15 and a VL having the sequence shown in SEQ ID NO: 20; (d) has a VH having the sequence shown in SEQ ID NO: 16 and a VL having the sequence shown in SEQ ID NO: 18; (e) has a VH having the sequence shown in SEQ ID NO: 17 and a VL having the sequence shown in SEQ ID NO: 19; (f) has a VH having the sequence shown in SEQ ID NO: 17 and a VL having the sequence shown in SEQ ID NO: 18; (g) has a VH having the sequence shown in SEQ ID NO: 29 and a VL having the sequence shown in SEQ ID NO: 30; or (h) has a VH having the sequence shown in SEQ ID NO: 31 and a VL having the sequence shown in SEQ ID NO: 32 and includes.

[0056] In certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention has a heavy chain variable region (VH) having at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the VH described in any one of (a)-(h); and / or a light chain variable region (VL) having at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the VL described in any one of (a)-(h).

[0057] In certain preferred embodiments, the antibody or antigen-binding fragment thereof comprises a heavy chain variable region (VH) having one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the VH in any one of (a)-(h); and / or a light chain variable region (VL) having one or several amino acid substitutions, deletions, or additions, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the VL in any one of (a)-(h); preferably, the substitution is a conservative substitution.

[0058] In any of the above embodiments, the antibody or antigen-binding fragment thereof according to the invention may further comprise a constant region sequence derived from a mammalian (e.g., mouse or human) immunoglobulin, or a variant thereof. In certain embodiments, the heavy chain of the antibody or antigen-binding fragment thereof according to the invention comprises the heavy chain constant region (CH) of a human or mouse immunoglobulin, or a variant thereof, wherein the variant has one or several amino acids substituted, deleted, or added, or any combination thereof (e.g., substitution, deletion, or addition of up to 20, up to 15, up to 10, up to 5 amino acids, or any combination thereof; e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the wild-type sequence from which it is derived; and / or the light chain of the antibody or antigen-binding fragment thereof according to the invention comprises the light chain constant region (CL) of a human or mouse immunoglobulin, or a variant thereof, wherein the variant has one or several amino acids substituted, deleted, or added, or any combination thereof (e.g., substitution, deletion, or addition of up to 20, up to 15, up to 10, up to 5 amino acids, or any combination thereof; e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) compared to the wild-type sequence from which it is derived.

[0059] In certain preferred embodiments, the heavy chain of an antibody or antigen-binding fragment thereof according to the invention comprises the heavy chain constant region (CH) of a human immunoglobulin, or a variant thereof, the variant having up to 20 conservative amino acid substitutions (e.g., up to 15, up to 10, up to 5 conservative amino acid substitutions; e.g., 5, 4, 3, 2, or 1 conservative amino acid substitution) compared to the wild-type sequence from which it is derived; and / or the light chain of an antibody or antigen-binding fragment thereof according to the invention comprises the light chain constant region (CL) of a human immunoglobulin, or a variant thereof, the variant having up to 20 conservative amino acid substitutions (e.g., up to 15, up to 10, up to 5 conservative amino acid substitutions; e.g., 5, 4, 3, 2, or 1 conservative amino acid substitution) compared to the wild-type sequence from which it is derived.

[0060] In certain preferred embodiments, the heavy chain of an antibody or antigen-binding fragment thereof according to the invention comprises the heavy chain constant region (CH) of a mouse immunoglobulin, or a variant thereof, the variant having up to 20 conservative amino acid substitutions (e.g., up to 15, up to 10, up to 5 conservative amino acid substitutions; e.g., 5, 4, 3, 2, or 1 conservative amino acid substitution) compared to the wild-type sequence from which it is derived. In certain embodiments, the light chain of an antibody or antigen-binding fragment thereof according to the invention comprises the light chain constant region (CL) of a mouse immunoglobulin, or a variant thereof, the variant having up to 20 conservative amino acid substitutions (e.g., up to 15, up to 10, up to 5 conservative amino acid substitutions; e.g., 5, 4, 3, 2, or 1 conservative amino acid substitution) compared to the wild-type sequence from which it is derived.

[0061] In some embodiments, the constant region is modified, for example, by amino acid mutation, to modify the properties of the anti-FXI and / or FXIa antibody molecule (e.g., the following properties: binding to Fc receptor, glycosylation of the antibody, number of cysteine residues, change one or more of the functions for effector cells or complement). Such a change in function can be achieved by replacing at least one amino acid residue in the constant region of the antibody with a different residue. For example, the effector function can be changed (e.g., reduced) by changing the affinity of the antibody for an effector ligand (e.g., FcR or complement C1q). The Fc region of the antibody mediates several important effector functions such as ADCC, phagocytosis, CDC, etc.

[0062] In certain embodiments, the antibody or antigen-binding fragment thereof according to the invention is selected from the heavy chain constant regions of, for example, IgG1, IgG2, IgG3, IgG4, IgM, IgA1, IgA2, IgD, and IgE; preferably, for example, selected from the heavy chain constant regions of IgG1, IgG2, IgG3, and IgG4; more preferably, selected from the heavy chain constant regions of IgG1 or IgG4 (e.g., human IgG1 or human IgG4), and has a heavy chain constant region (Fc). In some embodiments, the antibody or antigen-binding fragment thereof according to the invention has a light chain constant region selected from, for example, the κ light chain constant region or the λ light chain constant region, preferably the κ light chain constant region (e.g., human κ light chain).

[0063] In some preferred embodiments, the antibody or antigen-binding fragment thereof comprises a heavy chain constant region selected from (1) the human IgG1 heavy chain constant region; or (2) the human IgG4 heavy chain constant region.

[0064] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the invention (a) comprises a heavy chain constant region (CH) comprising an amino acid sequence selected from the following: (i) the sequence shown in SEQ ID NO: 21; (ii) a sequence having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof), as compared to the sequence shown in SEQ ID NO: 21; or (iii) a sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the sequence shown in SEQ ID NO: 21; and / or (b) a light chain constant region (CL) comprising an amino acid sequence selected from the following: (iv) the sequence shown in SEQ ID NO: 22; (v) a sequence having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof), as compared to the sequence shown in SEQ ID NO: 22; or (vi) a sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the sequence shown in SEQ ID NO: 22 comprising.

[0065] In certain preferred embodiments, the substitutions described in (ii) or (v) are conservative substitutions.

[0066] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention comprises a heavy chain constant region (CH) shown in SEQ ID NO: 21 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0067] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention is (a)(i) An array comprising VH shown in SEQ ID NO: 15 and CH shown in SEQ ID NO: 21; (ii) An array having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof) compared with the array shown in (i); or (iii) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (i) comprising a heavy chain containing an amino acid sequence selected from; and / or (b)(iv) An array comprising the VL sequence shown in SEQ ID NO: 18 and the CL sequence shown in SEQ ID NO: 22; (v) An array having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof) compared with the array shown in (iv); or (vi) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (iv) comprising a light chain containing an amino acid sequence selected from.

[0068] In certain preferred embodiments, the substitutions described in (ii) or (v) are conservative substitutions.

[0069] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention (a)(i) An array comprising VH shown in SEQ ID NO: 15 and CH shown in SEQ ID NO: 21; (ii) An array having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof), compared to the array shown in (i); or (iii) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (i) comprising a heavy chain comprising an amino acid sequence selected from (b) (iv) An array comprising the VL array shown in SEQ ID NO: 20 and the CL array shown in SEQ ID NO: 22; (v) An array having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof), compared to the array shown in (iv); or (vi) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (iv) comprising a light chain comprising an amino acid sequence selected from.

[0070] In certain preferred embodiments, the substitutions described in (ii) or (v) are conservative substitutions.

[0071] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention (a) (i) An array comprising the VH shown in SEQ ID NO: 16 and the CH shown in SEQ ID NO: 21; (ii) An array having substitutions, deletions, or additions of one or several amino acids, or any combination thereof (e.g., substitutions, deletions, or additions of one, two, three, four, or five amino acids, or any combination thereof), compared to the array shown in (i); or (iii) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (i) Comprising a heavy chain comprising an amino acid sequence selected from (b) (iv) An array comprising the VL array shown in SEQ ID NO: 18 and the CL array shown in SEQ ID NO: 22; (v) An array having substitutions, deletions, or additions of one or several amino acids, or any combination thereof (e.g., substitutions, deletions, or additions of one, two, three, four, or five amino acids, or any combination thereof), compared to the array shown in (iv); or (vi) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (iv) Comprising a light chain comprising an amino acid sequence selected from

[0072] In certain preferred embodiments, the substitutions described in (ii) or (v) are conservative substitutions.

[0073] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention (a) (i) An array comprising the VH shown in SEQ ID NO: 17 and the CH shown in SEQ ID NO: 21; (ii) An array having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof), compared with the array shown in (i); or (iii) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (i) A heavy chain comprising an amino acid sequence selected from (b) (iv) An array comprising the VL array shown in SEQ ID NO: 19 and the CL array shown in SEQ ID NO: 22; (v) An array having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of one, two, three, four, or five amino acids, or any combination thereof), compared with the array shown in (iv); or (vi) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (iv) Comprising a light chain comprising an amino acid sequence selected from.

[0074] In certain preferred embodiments, the substitutions described in (ii) or (v) are conservative substitutions.

[0075] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention (a) (i) An array comprising the VH shown in SEQ ID NO: 17 and the CH shown in SEQ ID NO: 21; (ii) An array having substitutions, deletions, or additions of one or several amino acids, or any combination thereof (e.g., substitutions, deletions, or additions of one, two, three, four, or five amino acids, or any combination thereof) compared to the array shown in (i); or (iii) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (i) A heavy chain comprising an amino acid sequence selected from; and / or (b) (iv) An array comprising the VL array shown in SEQ ID NO: 18 and the CL array shown in SEQ ID NO: 22; (v) An array having substitutions, deletions, or additions of one or several amino acids, or any combination thereof (e.g., substitutions, deletions, or additions of one, two, three, four, or five amino acids, or any combination thereof) compared to the array shown in (iv); or (vi) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (iv) Comprising a light chain comprising an amino acid sequence selected from.

[0076] In certain preferred embodiments, the substitutions described in (ii) or (v) are conservative substitutions.

[0077] In certain preferred embodiments, the substitutions described in (ii) or (v) are conservative substitutions.

[0078] In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention is (a) (i) An array comprising VH shown in SEQ ID NO: 31 and CH shown in SEQ ID NO: 21; (ii) An array having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) as compared with the array shown in (i); or (iii) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (i) selected amino acid sequences, and / or (b) (iv) An array comprising the VL sequence shown in SEQ ID NO: 32 and the CL sequence shown in SEQ ID NO: 22; (v) An array having substitution, deletion, or addition of one or several amino acids, or any combination thereof (e.g., substitution, deletion, or addition of 1, 2, 3, 4, or 5 amino acids, or any combination thereof) as compared with the array shown in (iv); or (vi) An array having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the array shown in (iv) selected amino acid sequences.

[0079] In a certain preferred embodiment, the substitution described in (ii) or (v) is a conservative substitution.

[0080] In certain preferred embodiments, the antibody of the present invention comprises a heavy chain comprising VH shown in SEQ ID NO: 1 and a heavy chain constant region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 2 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0081] In certain preferred embodiments, the antibody of the present invention comprises a heavy chain comprising VH shown in SEQ ID NO: 15 and a heavy chain constant region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 18 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0082] In certain preferred embodiments, the antibody of the present invention comprises a heavy chain comprising VH shown in SEQ ID NO: 15 and a heavy chain constant region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 20 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0083] In certain preferred embodiments, the antibody of the present invention comprises a heavy chain comprising VH shown in SEQ ID NO: 16 and a heavy chain constant region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 18 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0084] In certain preferred embodiments, the antibody of the present invention comprises a heavy chain comprising VH shown in SEQ ID NO: 17 and a heavy chain constant region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 19 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0085] In certain preferred embodiments, the antibody of the present invention comprises a heavy chain comprising VH shown in SEQ ID NO: 17 and a heavy chain constant region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 18 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0086] In certain preferred embodiments, the antibody of the present invention comprises a heavy chain comprising VH shown in SEQ ID NO: 29 and a heavy chain constant region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 30 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0087] In certain preferred embodiments, the antibody of the present invention comprises a heavy chain comprising VH shown in SEQ ID NO: 31 and a heavy chain constant region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 32 and a light chain constant region (CL) shown in SEQ ID NO: 22.

[0088] In certain preferred embodiments, the antibody of the present invention is a chimeric antibody or a humanized antibody. In certain preferred embodiments, the antibody or antigen-binding fragment thereof according to the present invention is selected from ScFv, Fab, Fab’, (Fab’)2, Fv fragment, disulfide-linked Fv (dsFv), diabody, bispecific antibody, and multispecific antibody.

[0089] In certain embodiments, the antibody or antigen-binding fragment thereof has reduced ADCC activity.

[0090] In certain embodiments, the antibody or antigen-binding fragment thereof has reduced CDC activity.

[0091] In certain embodiments, the antibody or antigen-binding fragment thereof has no CDC activity.

[0092] In certain embodiments, the antibody or antigen-binding fragment thereof has no ADCC activity.

[0093] In certain preferred embodiments, the antibody or antigen-binding fragment thereof reduces ADCC and reduces CDC activity.

[0094] In certain preferred embodiments, the antibody or antigen-binding fragment thereof has neither ADCC activity nor CDC activity.

[0095] In certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention has the following characteristics: (a) It binds to FXI and / or FXIa (e.g., human FXI and / or human FXIa) with a K of less than about 100 nM, such as less than about 10 nM, 1 nM, 0.1 nM, or less; D Preferably, the K D can be measured by techniques known in the art; for example, it can be measured by biolayer interferometry (BLI) (e.g., ForteBio Octet®). (b) It binds to FXI and / or FXIa (e.g., human FXI and / or human FXIa) with an EC of less than about 500 nM, such as less than about 100 nM, 10 nM, 1 nM, 0.9 nM, 0.8 nM, 0.7 nM, 0.6 nM, 0.5 nM, 0.4 nM, 0.3 nM, 0.2 nM, 0.1 nM, or less; 50 Preferably, the EC 50 can be measured by techniques known in the art; for example, it can be measured by flow cytometry or cell-based competitive ELISA. (c) The binding to FXI and / or FXIa inhibits or blocks the binding of FXI and / or FXIa to a substrate, thereby prolonging the clotting time; (d) The binding to FXI and / or FXIa inhibits or blocks the catalytic action of FXI and / or FXIa on a substrate; (e) The binding to FXI and / or FXIa does not affect extrinsic coagulation; (f) It reduces ADCC activity and / or CDC activity; (g) It does not have ADCC activity and / or CDC activity; (h) The binding to FXI and / or FXIa inhibits or blocks the formation of the dimer of FXI and / or the dimer of FXIa; (i) The binding to FXI and / or FXIa inhibits or blocks the formation of the complex of FXI and / or FXIa with HK; (j)Binding to the catalytic domain of FXI and / or FXIa and / or inducing a conformational change thereof; (k)Inhibiting or blocking the binding of FXI and / or FXIa to platelet receptors; or (l)Any combination of (a) to (k) having at least one of them.

[0096] In certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention, when binding to FXI, prevents the FXI catalytic domain from presenting an active conformation. In certain preferred embodiments, an antibody or antigen-binding fragment thereof according to the present invention, when binding to FXI, prevents the FXI catalytic domain from presenting an active conformation by inducing a conformational change in the prothrombin structure, thereby further inhibiting binding to FIX.

[0097] Derivative antibody An antibody or antigen-binding fragment thereof according to the present invention can be derivatized, for example, by being linked to another molecule (e.g., another polypeptide or protein). Generally, derivatization (e.g., labeling) of the antibody or antigen-binding fragment thereof will not have an adverse effect on its binding to FXI and / or FXIa (especially human FXI and / or FXIa). Thus, an antibody or antigen-binding fragment thereof according to the present invention is also intended to include such derivatized forms. For example, an antibody or antigen-binding fragment thereof according to the present invention can be functionally linked (by chemical coupling, gene fusion, non-covalent linkage, or other means) to one or more other molecular groups, such as another antibody (e.g., forming a bispecific antibody), a detection reagent, a pharmaceutical reagent, and / or a protein or polypeptide (e.g., avidin or a polyhistidine tag) capable of mediating the binding of the antibody or antigen-binding fragment thereof to another molecule.

[0098] One type of derivatized antibody (e.g., bispecific antibody) is produced by crosslinking two or more antibodies (of the same or different types). In the art, methods for obtaining such bispecific antibodies are well known and examples include, but are not limited to, chemical crosslinking methods, cell manipulation methods (hybrid hybridoma method), or genetic manipulation methods.

[0099] Another type of derivatized antibody is a labeled antibody. For example, an antibody or an antigen-binding fragment thereof according to the present invention can be linked to a detection label. The detection label of the present invention can be any substance that can be detected by fluorescence, spectroscopy, photochemistry, biochemistry, immunology, electrical means, optical means, or chemical means. Such labels are well known in the art and examples include enzymes (e.g., horseradish peroxidase, alkaline phosphatase, β-galactosidase, urease, glucose oxidase, etc.), radionuclides (e.g., 3 H, 125 I, 35 S, 14 C, or 32P), fluorescent dyes (e.g., fluorescein isothiocyanate (FITC), fluorescein, tetramethylrhodamine isothiocyanate (TRITC), phycoerythrin (PE), Texas Red, rhodamine, quantum dots, or cyanine dye derivatives (e.g., Cy7, Alexa 750)), acridinium ester compounds, magnetic beads (e.g., Dynabeads®), gold colloids or colored glass or colored plastic (e.g., polystyrene, polypropylene, latex, etc.) beads and other colorimetric labels, and biotin for binding to avidin (e.g., streptavidin) modified by the above-described labels, but not limited thereto. Patents teaching the use of these labels include, but are not limited to, U.S. Patent Nos. 3,817,837; 3,850,752; 3,939,350; 3,996,345; 4,277,437; 4,275,149; and 4,366,241 (all of which are incorporated herein by reference). The detection labels described above can be detected by methods known in the art. For example, radioactive labels can be detected using photographic film or scintillation counters, and fluorescent labels that can be detected using a photodetector that detects luminescence. Enzyme labels are generally detected by providing a substrate for the enzyme and detecting the reaction product resulting from the action of the enzyme on the substrate, and colorimetric labels are detected by simple visualization of the colored label. In some embodiments, such labels may be suitable for immunological detection (e.g., enzyme immunoassay, radioimmunoassay, fluorescence immunoassay, chemiluminescent immunoassay, etc.). In some embodiments, the detection labels described above can be linked to an antibody or antigen-binding fragment thereof according to the present invention via linkers of different lengths so as to reduce potential steric hindrance.

[0100] In addition, the antibodies or antigen-binding fragments thereof according to the present invention may also be derivatized with chemical groups such as polyethylene glycol (PEG) groups, methyl or ethyl groups, or sugar groups. These groups can be used to improve the biological properties of the antibody, such as extending its serum half-life.

[0101] As one of the antibody derivatives, the present invention provides a conjugate. In some embodiments, the conjugate comprises any antibody or antigen-binding fragment thereof that specifically binds to FXI and / or FXIa according to the present invention and a conjugate moiety, and the conjugate moiety is a detection label such as a radioisotope, a fluorescent substance, a luminescent substance, a colored substrate, or an enzyme described above. In certain embodiments, the conjugate moiety is a therapeutic agent; optionally, the therapeutic agent binds to one or more of the antibodies or antigen-binding fragments thereof according to the present invention via a linker. Optionally, the therapeutic agent is bound to the antibody or antigen-binding fragment thereof according to the present invention via a linker. The therapeutic agent is selected from any one of the drugs mentioned in the uses, therapies, and pharmaceutical compositions of the present disclosure. The linker does not have a significant impact on the biological activity of the antibody or antigen-binding fragment thereof according to the present invention.

[0102] As one of the antibody derivatives, the present invention provides a multispecific antibody comprising an antibody or antigen-binding fragment thereof that specifically binds to FXI and / or FXIa according to the present invention, and another antibody or antigen-binding fragment thereof, or an antibody mimetic. In some embodiments, the multispecific antibody is a conjugate comprising an antibody or antigen-binding fragment thereof that specifically binds to FXI and / or FXIa according to the present invention, and another antibody or antigen-binding fragment thereof, or an antibody mimetic.

[0103] In certain embodiments, the multispecific antibody is formed by coupling an antibody or antigen-binding fragment thereof that specifically binds to FXI and / or FXIa, according to the invention, to another antibody or antigen-binding fragment thereof, or an antibody mimetic, where each antibody or antigen-binding fragment thereof, or antibody mimetic maintains its original binding specificity. In certain preferred embodiments, the multispecific antibody is a bispecific antibody or a trispecific antibody or a tetravalent antibody.

[0104] Preparation of antibody The antibodies of the invention may be prepared by a variety of methods known in the art, and may be obtained, for example, by recombinant techniques involving genetic manipulation. For example, the DNA molecules encoding the heavy and light chain genes of the antibodies of the invention are obtained by chemical synthesis or PCR amplification. The resulting DNA molecules are inserted into expression vectors, which are then transfected into host cells. The transfected host cells are then cultured under specific conditions to express the antibodies of the invention.

[0105] The antigen-binding fragments of the present invention can be obtained by hydrolyzing intact antibody molecules (see Morimoto et al., J. Biochem. Biophys. Methods, 24: 107-117 (1992); and Brennan et al., Science, 229: 81 (1985)). In addition, these antigen-binding fragments can also be produced directly by recombinant host cells (reviewed in Hudson, Curr. Opin. Immunol., 11: 548-557 (1999); Little et al., Immunol. Today, 21: 364-370 (2000)). For example, Fab' fragments may be obtained directly from host cells; Fab' fragments can be chemically coupled to form F(ab')2 fragments (Carter et al., Bio / Technology, 10: 163-167 (1992)). In addition, Fv fragments, Fab fragments, or F(ab')2 fragments can also be isolated directly from the culture medium of recombinant host cells. Those skilled in the art are well aware of other techniques for preparing these antigen-binding fragments.

[0106] Accordingly, in another aspect, the present invention provides an isolated nucleic acid molecule comprising a nucleotide sequence encoding an antibody or an antigen-binding fragment thereof, or a heavy chain variable region and / or a light chain variable region thereof, or one or more CDRs thereof, according to the present invention. In some embodiments, the nucleotide sequence can be replaced based on the degeneracy of codons, according to the degeneracy of codons known in the art. In certain embodiments, the nucleotide sequence is codon-optimized.

[0107] In certain preferred embodiments, the isolated nucleic acid molecule comprises a first nucleic acid and a second nucleic acid encoding, respectively, the heavy chain variable region and the light chain variable region of an antibody or an antigen-binding fragment thereof according to the invention, or a first nucleic acid encoding the heavy chain variable region and the heavy chain constant region of an antibody or an antigen-binding fragment thereof according to the invention, and a second nucleic acid encoding the light chain variable region and the light chain constant region, or a first nucleic acid and a second nucleic acid encoding, respectively, the heavy chain and the light chain of an antibody or an antigen-binding fragment thereof according to the invention. In certain preferred embodiments, the antibody of the invention described above is selected from any one of the following group: 36G9.10, 36G9.10-hz43, 36G9.10-hz73, 36G9.10-hz74, 36G9.10-hz92, 36G9.10-hz93, 7B2, 7B2-hz11. In certain preferred embodiments, the first nucleic acid and the second nucleic acid comprise nucleic acids having a sequence substantially the same as the first nucleic acid and the second nucleic acid described above. For example, the isolated nucleic acid molecule may comprise the nucleotide sequences shown in SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 27, SEQ ID NO: 28 in the Sequence Listing, or sequences substantially identical thereto. For example, a sequence substantially identical thereto refers to a sequence having at least about 85%, 90%, 95%, 99%, or more identity to the sequence being compared, or a sequence having one or more nucleotide substitutions, or a sequence that does not differ by more than 3, 6, 15, 30, or 45 nucleotides.

[0108] In certain preferred embodiments, the invention includes a nucleic acid molecule encoding a heavy chain variable region of an antibody and / or a nucleic acid molecule encoding a light chain variable region of an antibody, wherein the nucleic acid molecule encoding the heavy chain variable region of the antibody has a nucleotide sequence selected from the group consisting of: (a) the nucleotide sequence set forth in SEQ ID NO: 23, or (b) a sequence that is substantially the same as the nucleotide sequence recited in (a) (e.g., a sequence having at least about 85%, 90%, 95%, 99%, or more identity compared to the nucleotide sequence recited in (a), or a sequence having one or more nucleotide substitutions), or (c) a nucleotide sequence that differs from the nucleotide sequence recited in (a) by no more than 3, 6, 15, 30, or 45 nucleotides; and the nucleic acid molecule encoding the light chain variable region of the antibody has a sequence selected from the group consisting of: (d) the nucleotide sequence set forth in SEQ ID NO: 24, or (e) a sequence that is substantially the same as the nucleotide sequence recited in (d) (e.g., a sequence having at least about 85%, 90%, 95%, 99%, or more identity compared to the nucleotide sequence recited in (d), or a sequence having one or more nucleotide substitutions), or (f) a sequence that differs from the nucleotide sequence recited in (d) by no more than 3, 6, 15, 30, or 45 nucleotides, and provides an isolated nucleic acid molecule.

[0109] In certain preferred embodiments, the isolated nucleic acid molecule of the present invention comprises a nucleic acid molecule encoding the heavy chain variable region of an antibody and / or a nucleic acid molecule encoding the light chain variable region of an antibody, wherein the nucleic acid molecule encoding the heavy chain variable region of the antibody has a nucleotide sequence selected from the group consisting of: (a) the nucleotide sequence set forth in SEQ ID NO: 27, or (b) a sequence that is substantially the same as the nucleotide sequence described in (a) (e.g., a sequence having at least about 85%, 90%, 95%, 99% or more identity compared to the nucleotide sequence described in (a), or a sequence having one or more nucleotide substitutions), or (c) a nucleotide sequence that differs from the nucleotide sequence described in (a) by no more than 3, 6, 15, 30 or 45 nucleotides; and the nucleic acid molecule encoding the light chain variable region of the antibody has a nucleotide sequence selected from the group consisting of: (d) the nucleotide sequence set forth in SEQ ID NO: 28, or (e) a sequence that is substantially the same as the nucleotide sequence described in (d) (e.g., a sequence having at least about 85%, 90%, 95%, 99% or more identity compared to the nucleotide sequence described in (d), or a sequence having one or more nucleotide substitutions), or (f) a sequence that differs from the nucleotide sequence described in (d) by no more than 3, 6, 15, 30 or 45 nucleotides.

[0110] In certain preferred embodiments, the isolated nucleic acid molecule of the present invention comprises the nucleic acid molecule set forth in SEQ ID NO: 23 encoding the heavy chain variable region of an antibody and / or the nucleic acid molecule set forth in SEQ ID NO: 24 encoding the light chain variable region of an antibody.

[0111] In certain preferred embodiments, the isolated nucleic acid molecule of the present invention comprises the nucleic acid molecule set forth in SEQ ID NO: 27 encoding the heavy chain variable region of an antibody and / or the nucleic acid molecule set forth in SEQ ID NO: 28 encoding the light chain variable region of an antibody.

[0112] In certain preferred embodiments, the invention includes a nucleic acid molecule encoding an antibody heavy chain and / or a nucleic acid molecule encoding an antibody light chain, wherein the nucleic acid molecule encoding the antibody heavy chain has a nucleotide sequence selected from the group consisting of: (a) the nucleotide sequence set forth in SEQ ID NO: 25; (b) a nucleotide sequence that is substantially the same as the nucleotide sequence recited in (a) (e.g., having at least about 85%, 90%, 95%, 99%, or more identity to the nucleotide sequence recited in (a), or a sequence having one or more nucleotide substitutions); or (c) a nucleotide sequence that differs from the nucleotide sequence recited in (a) by no more than 3, 6, 15, 30, or 45 nucleotides; and / or the nucleic acid molecule encoding the antibody light chain has a nucleotide sequence selected from the group consisting of: (d) the nucleotide sequence set forth in SEQ ID NO: 26; (e) a nucleotide sequence that is substantially the same as the nucleotide sequence recited in (d) (e.g., having at least about 85%, 90%, 95%, 99%, or more identity to the nucleotide sequence recited in (d), or a sequence having one or more nucleotide substitutions); or (f) a nucleotide sequence that differs from the nucleotide sequence recited in (d) by no more than 3, 6, 15, 30, or 45 nucleotides, provided as an isolated nucleic acid molecule.

[0113] In certain preferred embodiments, the isolated nucleic acid molecule of the invention comprises a nucleic acid molecule encoding an antibody heavy chain, set forth in SEQ ID NO: 25, and / or a nucleic acid molecule encoding an antibody light chain, set forth in SEQ ID NO: 26.

[0114] Another aspect of the invention provides a vector (e.g., a cloning vector or an expression vector) comprising the isolated nucleic acid molecule of the invention. In certain preferred embodiments, the vector of the invention is, for example, a plasmid, cosmid, bacteriophage, lentivirus, etc. In certain preferred embodiments, the vector is capable of expressing an antibody or an antigen-binding fragment thereof according to the invention in a subject (e.g., a mammal such as a human).

[0115] Another aspect of the present invention provides a host cell comprising the isolated nucleic acid molecule of the present invention or the vector of the present invention. The host cell may be a eukaryotic cell (e.g., mammalian cell, insect cell, yeast cell) or a prokaryotic cell (e.g., Escherichia coli). Suitable eukaryotic cells include, but are not limited to, NS0 cells, Vero cells, Hela cells, COS cells, CHO cells, HEK293 cells, BHK cells, and MDCKII cells. Suitable insect cells include, but are not limited to, Sf9 cells. In certain preferred embodiments, the host cell of the present invention is a mammalian cell such as a CHO (e.g., CHO-K1, CHO-S, CHO DXB11, CHO DG44) cell.

[0116] Another aspect of the present invention provides a method for preparing an antibody or an antigen-binding fragment thereof according to the present invention, the method comprising culturing the host cell of the present invention under conditions that allow the expression of the antibody or an antigen-binding fragment thereof, and recovering the antibody or an antigen-binding fragment thereof from the culture of the cultured host cell.

[0117] Use, treatment method, and pharmaceutical composition Another aspect of the present invention provides a pharmaceutical composition comprising an antibody or an antigen-binding fragment thereof, an isolated nucleic acid molecule, a vector, a host cell, a multispecific antibody, or a conjugate according to the present invention, and a pharmaceutically acceptable carrier and / or excipient.

[0118] In certain preferred embodiments, the pharmaceutical composition of the present invention comprises an antibody or an antigen-binding fragment thereof according to the present invention and a pharmaceutically acceptable carrier and / or excipient.

[0119] In certain preferred embodiments, the pharmaceutical composition of the present invention comprises an isolated nucleic acid molecule, a vector, or a host cell according to the present invention and a pharmaceutically acceptable carrier and / or excipient. In such embodiments, the host cell comprises the isolated nucleic acid molecule or vector already described.

[0120] In certain preferred embodiments, the pharmaceutical composition may further comprise an additional pharmaceutically active agent. In certain preferred embodiments, the additional pharmaceutically active agent is an antiplatelet agent, an anticoagulant, or a thrombolytic agent.

[0121] In certain preferred embodiments, in the pharmaceutical composition, the antibody or antigen-binding fragment thereof according to the present invention and the additional pharmaceutically active agent are provided as separate components or as components of a single composition. Thus, the antibody or antigen-binding fragment thereof according to the present invention and the additional pharmaceutically active agent may be administered simultaneously, separately, or sequentially.

[0122] In certain preferred embodiments, the pharmaceutical composition may further comprise an additional pharmaceutically active agent. The additional pharmaceutically active agent is selected from the group consisting of aspirin, clopidogrel, prasugrel, ticagrelor, abciximab, eptifibatide, vorapaxar, unfractionated heparin, heparin, low molecular weight heparin, warfarin, fondaparinux, edoxaban, betrixaban, rivaroxaban, apixaban, dabigatran etexilate, argatroban, bivalirudin, streptokinase, urokinase, alteplase, prourokinase, or any combination thereof.

[0123] In another aspect, the antibody or antigen-binding fragment thereof, isolated nucleic acid molecule, vector, host cell, bispecific antibody, or conjugate in the pharmaceutical composition of the present invention has the following biological activities in a subject: (a) binding to the catalytic domain of FXI and / or FXIa and / or inducing a conformational change thereof; (b) inhibiting or blocking the binding of FXI and / or FXIa to a substrate; (c) inhibiting or blocking the binding of FXI and / or FXIa to a platelet receptor; (d) inhibiting or blocking the binding of FXI to factor XIIa (FXIIa), thereby inhibiting or blocking the conversion of FXI to active FXIa; (e) inhibiting or blocking the binding of FXIa to factor FIX, thereby inhibiting or blocking the conversion of FIX to active FIXa; (f) inhibiting or blocking the activation of the intrinsic coagulation pathway mediated by FXI and / or FXIa; (g) inhibiting or blocking the activity of FXI and / or FXIa in thrombosis; (h) prolonging the clotting time mediated by FXI and / or FXIa; (i) inhibiting thrombosis; (j) preventing and / or treating diseases or disorders associated with coagulation or thromboembolism mediated by FXI and / or FXIa; or (k) any combination of (a)-(j) is sufficient to effect at least one of.

[0124] In another aspect, the pharmaceutical composition of the invention further comprises a second antibody, or a nucleic acid encoding a second antibody, wherein the second antibody is another antibody that recognizes a different epitope of FXI or FXIa, or an antibody that specifically binds to a receptor or ligand selected from the group consisting of thrombin, antithrombin, factor XII, factor VIII, factor VII, factor X, factor IX, factor II, tissue factor, P-selectin and its ligand, L-selectin and its ligand, and any combination of the above antibodies.

[0125] Another aspect of the invention provides the use of an antibody or an antigen-binding fragment thereof, an isolated nucleic acid molecule, a vector, a host cell, a multispecific antibody, a conjugate, or a pharmaceutical composition of the invention in the manufacture of a medicament, the medicament being (a) binding to the catalytic domain of FXI and / or FXIa and / or inducing a conformational change thereof; (b) inhibiting or blocking the binding of FXI and / or FXIa to a substrate; (c) inhibiting or blocking the binding of FXI and / or FXIa to platelet receptors; (d) inhibiting or blocking the binding of FXI to factor XIIa (FXIIa), thereby inhibiting the conversion of FXI to active FXIa; (e) inhibiting or blocking the binding of FXIa to coagulation factor FIX, thereby inhibiting the conversion of FIX to active FIXa; (f) inhibiting or blocking the activation of the intrinsic coagulation pathway mediated by FXI and / or FXIa; (g) inhibiting or blocking the activity of FXI and / or FXIa in thrombosis; (h) prolonging the clotting time mediated by FXI and / or FXIa; (i) inhibiting thrombosis; (j) preventing and / or treating diseases or disorders associated with coagulation or thromboembolism mediated by FXI and / or FXIa; or (k) any combination of (a) to (j) for use.

[0126] In certain preferred embodiments, when the isolated nucleic acid molecule, vector, or host cell of the present invention is used for the manufacture of a medicament, the host cell contains the isolated nucleic acid molecule or vector described above.

[0127] In certain preferred embodiments, when the vector or host cell of the present invention is used for the manufacture of a medicament, the medicament is used for the prevention and / or treatment of diseases or disorders associated with coagulation or thromboembolism in a subject (e.g., a human).

[0128] In certain embodiments, the subject is a mammal. In certain preferred embodiments, the subject is a human.

[0129] In certain preferred embodiments, when the vector or host cell of the present invention is used for the manufacture of a medicament, the medicament is used in a subject (e.g., a human) to delay the occurrence of a disease or disorder associated with coagulation or thromboembolism.

[0130] In certain preferred embodiments, when the vector or host cell of the present invention is used for the manufacture of a medicament, the medicament is used in a subject (e.g., a human) to reduce or inhibit the recurrence of a disease or disorder associated with coagulation or thromboembolism.

[0131] In certain preferred embodiments, when the vector or host cell of the present invention is used for the manufacture of a medicament, the medicament is used in a subject (e.g., a human).

[0132] In certain preferred embodiments, the antibody or antigen-binding fragment thereof, isolated nucleic acid molecule, vector, host cell, multispecific antibody, conjugate, or pharmaceutical composition of the invention is involved in a disease or disorder associated with coagulation or thromboembolism selected from the group consisting of thrombosis, thrombotic stroke, atrial fibrillation, stroke prevention associated with atrial fibrillation (SPAF), deep vein thrombosis, venous thromboembolism, acute coronary syndrome (ACS), ischemic stroke, acute limb ischemia, chronic thromboembolic pulmonary hypertension, systemic embolism, myocardial infarction (MI), acute myocardial infarction (AMI), stable angina, unstable angina, restenosis and reocclusion after coronary intervention, peripheral arterial occlusive disease (PAOD), renal vein thrombosis, transient ischemic attack (TIA), pulmonary thromboembolism, disseminated intravascular coagulation, thromboembolic disorders caused by medical devices (e.g., catheters), severe systemic inflammatory response syndrome, metastatic cancer, infectious diseases, organ failure (e.g., renal failure), toxicity caused by administration of therapeutic proteins in the body, multiple trauma, ischemia-reperfusion injury, local fibrin deposition, adult respiratory distress syndrome, venous thromboembolic events (VTE) before and after total knee arthroplasty (TKA), coronary heart disease, thromboembolism after myocardial infarction, stroke in patients with non-valvular atrial fibrillation, thrombosis and thromboembolism in chronic kidney disease, thrombosis and thromboembolism in patients undergoing hemodialysis and extracorporeal membrane oxygenation, deep vein thrombosis (DVT), or pulmonary embolism (PE).

[0133] In another aspect, the present invention provides a method for preventing and / or treating a disease or disorder associated with coagulation or thromboembolism in a subject. In another aspect, the present invention provides a method for delaying the onset of a disease or disorder associated with coagulation or thromboembolism in a subject. In another aspect, the present invention provides a method for reducing or inhibiting the recurrence of a disease or disorder associated with coagulation or thromboembolism in a subject. The methods described above include the step of administering to a subject in need thereof an effective amount of an antibody or an antigen-binding fragment thereof, a vector, a host cell, a bispecific antibody, a conjugate, or a pharmaceutical composition of the present invention.

[0134] When the host cell of the present invention is used in the method described above, the host cell contains the isolated nucleic acid molecule or vector described above.

[0135] In another aspect, the method above further includes the step of administering a second treatment to the subject, where the second treatment is selected from the group consisting of antiplatelet agents, anticoagulants, and thrombolytics.

[0136] In certain preferred embodiments, the second treatment is selected from aspirin, clopidogrel, prasugrel, ticagrelor, abciximab, eptifibatide, vorapaxar, unfractionated heparin, heparin, low molecular weight heparin, warfarin, fondaparinux, edoxaban, betrixaban, rivaroxaban, apixaban, dabigatran etexilate, argatroban, bivalirudin, streptokinase, urokinase, alteplase, prourokinase, and any combination thereof.

[0137] In certain preferred embodiments, the antibodies or antigen-binding fragments thereof, isolated nucleic acid molecules, vectors, host cells, bispecific antibodies, conjugates, or pharmaceutical compositions of the invention are involved in diseases or disorders associated with coagulation or thromboembolism selected from the group consisting of thrombosis, thrombotic stroke, atrial fibrillation, stroke prevention associated with atrial fibrillation (SPAF), deep vein thrombosis, venous thromboembolism, acute coronary syndrome (ACS), ischemic stroke, acute limb ischemia, chronic thromboembolic pulmonary hypertension, systemic embolism, myocardial infarction (MI), acute myocardial infarction (AMI), stable angina, unstable angina, restenosis and reocclusion after coronary intervention, peripheral arterial occlusive disease (PAOD), renal vein thrombosis, transient ischemic attack (TIA), pulmonary thromboembolism, disseminated intravascular coagulation, thromboembolic disorders caused by medical devices (e.g., catheters), severe systemic inflammatory response syndrome, metastatic cancer, infectious diseases, organ failure (e.g., renal failure), toxicity caused by administration of therapeutic proteins in the body, multiple trauma, ischemia-reperfusion injury, local fibrin deposition, adult respiratory distress syndrome, venous thromboembolic events (VTE) before and after total knee arthroplasty (TKA), coronary heart disease, thromboembolism after myocardial infarction, stroke in patients with non-valvular atrial fibrillation, thrombosis and thromboembolism in chronic kidney disease, thrombosis and thromboembolism in patients undergoing hemodialysis and patients receiving extracorporeal membrane oxygenation, deep vein thrombosis (DVT), or pulmonary embolism (PE).

[0138] The antibody or antigen-binding fragment thereof according to the present invention, and the pharmaceutical composition of the present invention can be formulated into any dosage form known in the medical field, for example, tablets, pills, suspensions, emulsions, solutions, gels, capsules, powders, granules, elixirs, troches, suppositories, injections (including injection solutions, sterile powders for injection, and concentrated solutions for injection), inhalants, sprays, etc. The preferred dosage form depends on the intended mode of administration and therapeutic use. The pharmaceutical composition of the present invention shall be sterile and stable under the conditions of production and storage. The preferred dosage form is an injection. Such an injection can be a sterile injection solution. For example, a sterile injection solution can be prepared by the following method: incorporating the required dose of the recombinant protein of the present invention into a suitable solvent, and optionally, simultaneously incorporating other desired components (including but not limited to pH adjusters, surfactants, adjuvants, ionic strength enhancers, isotonic agents, preservatives, diluents, or any combination thereof), followed by filtration and sterilization. In addition, a sterile injection solution can be prepared as a sterile lyophilized powder (for example, via vacuum drying or freeze drying) for storage and use. Such a sterile lyophilized powder can be dispersed in a suitable carrier, such as sterile pyrogen-free water, before use.

[0139] In addition, the antibody or antigen-binding fragment thereof according to the present invention can be present in a pharmaceutical composition in unit dosage form for easy administration.

[0140] The antibody or antigen-binding fragment thereof, and the pharmaceutical composition of the present invention can be administered by any suitable method known in the art, including but not limited to oral route, intraoral route, sublingual route, intraocular route, topical route, parenteral route, rectal route, intrathecal route, intracapsular route, inguinal route, intravesical route, local (such as powder, ointment, or drops) route, or nasal route. However, in many therapeutic applications, the preferred route of administration / administration mode is parenteral administration (e.g., intravenous injection, subcutaneous injection, intraperitoneal injection, intramuscular injection). Those skilled in the art should understand that the route of administration / administration mode may vary according to the intended purpose. In a preferred embodiment, the antibody or antigen-binding fragment thereof, or the pharmaceutical composition of the present invention, is administered by intravenous infusion or intravenous injection.

[0141] The pharmaceutical composition of the present invention may contain a "therapeutically effective amount" or "prophylactically effective amount" of the antibody or antigen-binding fragment thereof, isolated nucleic acid molecule, vector, host cell, bispecific antibody, or conjugate of the present invention. A "prophylactically effective amount" is an amount sufficient to prevent, arrest, or delay the onset of a disease. A "therapeutically effective amount" is an amount sufficient to cure or at least partially arrest a disease and its complications in a patient already suffering from the disease. The therapeutically effective amount of the antibody or antigen-binding fragment thereof according to the present invention may vary according to factors such as the severity of the disease to be treated, the overall status of the patient's own immune system, age, weight, and gender, the general condition of the patient, the mode of drug administration, and other treatments administered simultaneously.

[0142] In the present invention, the dosing regimen can be adjusted to obtain the desired best response (e.g., therapeutic response or prophylactic response). For example, administration may be made as a single dose, may be administered multiple times over a period of time, and the dose may be reduced or increased depending on the urgency of the treatment situation.

[0143] Typical non-limiting ranges of a therapeutically effective amount or a prophylactically effective amount of the recombinant protein of the present invention are 0.02 to 100 mg / kg, such as 0.1 to 100 mg / kg, 0.1 to 50 mg / kg, or 1 to 50 mg / kg. It should be noted that the dosage may vary depending on the type and severity of the symptoms to be treated. In addition, those skilled in the art will appreciate that for any particular patient, a detailed dosing regimen should be adjusted over time in accordance with the patient's needs and the physician's professional judgment; and that the dosage ranges provided herein are for illustrative purposes only and are not intended to limit the use or scope of the pharmaceutical compositions of the present invention.

[0144] In the present invention, the subject can be a mammal such as a human.

[0145] Detection method and kit The antibody or antigen-binding fragment thereof according to the present invention can specifically bind to FXI and / or FXIa (e.g., human FXI and / or human FXIa), and thus can be used to detect the presence or level of FXI and / or FXIa in a sample.

[0146] Accordingly, in another aspect, the present invention provides a kit comprising an antibody or an antigen-binding fragment thereof according to the present invention. In certain preferred embodiments, the antibody or an antigen-binding fragment thereof according to the present invention bears a detectable label. In a preferred embodiment, the kit further comprises a second antibody that specifically recognizes the antibody or an antigen-binding fragment thereof according to the present invention. Preferably, the second antibody further comprises a detectable label.

[0147] In the present invention, the detection label can be any substance that can be detected by fluorescence, spectroscopy, photochemical means, biochemical means, immunological means, electrical means, optical means, or chemical means. Such labels can be particularly preferably applied to immunological detection (for example, enzyme immunoassay, radioimmunoassay, fluorescence immunoassay, chemiluminescence immunoassay, etc.). In the art, such labels are well known and include enzymes (for example, horseradish peroxidase, alkaline phosphatase, β-galactosidase, urease, glucose oxidase, etc.), radionuclides (for example, 3 H, 125 I, 35 S, 14 C, or 32P), fluorescent dyes (e.g., fluorescein isothiocyanate (FITC), fluorescein, tetramethylrhodamine isothiocyanate (TRITC), phycoerythrin (PE), Texas Red, rhodamine, quantum dots, or cyanine dye derivatives (e.g., Cy7, Alexa 750)), acridinium ester compounds, magnetic beads (e.g., Dynabeads®), gold colloids or colored glass or colored plastic (e.g., polystyrene, polypropylene, latex, etc.) beads, and biotin for binding to avidin (e.g., streptavidin) modified by the above-described labels, among others. Patents teaching the use of these labels include, but are not limited to, U.S. Patent Nos. 3,817,837; 3,850,752; 3,939,350; 3,996,345; 4,277,437; 4,275,149; and 4,366,241 (all of which are incorporated herein by reference). The detection labels described above can be detected by methods known in the art. For example, radioactive labels can be detected using photographic film or scintillation counters, and fluorescent labels that can be detected using a photodetector that detects luminescence. Enzyme labels are generally detected by providing a substrate for the enzyme and detecting the reaction product resulting from the action of the enzyme on the substrate, and colorimetric labels are detected by simple visualization of the colored label. In some embodiments, the detection labels described above can be linked to an antibody or antigen-binding fragment thereof according to the present invention via linkers of different lengths so as to reduce potential steric hindrance.

[0148] In another aspect, the present invention provides a method for detecting the presence or level of FXI and / or FXIa (e.g., human FXI and / or human FXIa) in a sample, the method comprising the step of using an antibody or an antigen-binding fragment thereof according to the present invention. In a preferred embodiment, the antibody or an antigen-binding fragment thereof according to the present invention also bears a detection label. In another preferred embodiment, the method further comprises the step of using a reagent bearing a detection label for detecting the antibody or an antigen-binding fragment thereof according to the present invention. The method may be used for diagnostic purposes or for non-diagnostic purposes (e.g., the sample is a cell sample and not a sample derived from a patient).

[0149] In another aspect, the present invention provides a method for detecting the presence or level of FXI and / or FXIa (e.g., human FXI and / or human FXIa) in a sample, the method comprising the step of contacting a sample with an antibody or an antigen-binding fragment thereof according to the present invention under conditions that allow formation of a complex between the antibody or an antigen-binding fragment thereof or conjugate and FXI and / or FXIa.

[0150] In another aspect, there is provided the use of an antibody or an antigen-binding fragment thereof according to the present invention in the manufacture of a kit for detecting the presence or level of FXI and / or FXIa (e.g., human FXI and / or human FXIa) in a sample. In another aspect, the present invention provides a diagnostic or therapeutic kit comprising one or more of the following substances that the present invention can provide: an antibody or an antigen-binding fragment thereof, an isolated nucleic acid molecule, a vector, a host cell, a bispecific antibody, a conjugate, or a pharmaceutical composition. The diagnostic or therapeutic kit also includes instructions for use.

[0151] The antibody or antigen-binding fragment of the present invention has a high binding affinity for FXI and / or FXIa and extremely strong specificity. Therefore, the antibody or antigen-binding fragment of the present invention is suitable for the prevention and / or treatment of diseases or disorders associated with coagulation or thromboembolism. The humanized antibody of the present invention retains the functions and characteristics of the parental mouse antibody. Furthermore, the humanized antibody of the present invention is highly humanized so as to be safely administered to human subjects without inducing an immunogenic reaction. In addition, the antibody or antigen-binding fragment of the present invention has no or almost no risk of bleeding. Therefore, the antibody or antigen-binding fragment of the present invention has great clinical value.

[0152] Definitions of abbreviations and terms CDR Complementary determining region in the immunoglobulin variable region FR Framework region of the antibody: Amino acid residues other than the CDR residues in the antibody variable region VH Variable region of the heavy chain of the antibody VL Variable region of the light chain of the antibody IgG Immunoglobulin G Kabat The alignment and numbering system of immunoglobulins proposed by Elvin A. Kabat (see, for example, Kabat et al., "Sequences of Proteins of Immunological Interest", 5th edition, Public Health Service, National Institutes of Health, Bethesda, Md., 1991) Chothia The numbering system of immunoglobulins proposed by Chothia et al., which is a classical rule for identifying the boundaries of CDR regions based on the positions of structural loop regions (see, for example, Chothia and Lesk (1987), J. Mol. Biol., 196: 901-917; Chothia (1989), Nature, 342: 878-883) The definition by AbM AbM CDR is derived from the relevant research of Martin (Martin ACR, Cheetham JC, Rees AR (1989), "Modelling antibody hypervariable loops: A combined algorithm", Proc Natl Acad Sci USA 86: 9268-9272), and this definition method integrates the partial definition of Kabat and the partial definition of Chothia The numbering system based on the International ImMunoGeneTics (IMGT) information system (registered trademark) founded by IMGT Lefranc et al. (see Lefranc et al., Dev. Comparat. Immunol. 27: 55-77, 2003) mAb Monoclonal antibody EC50 The concentration at which 50% efficacy or binding is achieved IC50 The concentration at which 50% inhibition is achieved ELISA Enzyme-linked immunosorbent assay PCR Polymerase chain reaction HRP Horseradish peroxidase KD Equilibrium dissociation constant Ka Association rate constant Kd Dissociation rate constant ADCC Antibody-dependent cell-mediated cytotoxicity CDC Complement-dependent cytotoxicity FACS Fluorescence-activated cell sorting CDR-H1 Complementary determining region 1 in the variable region of immunoglobulin heavy chain CDR-H2 Complementary determining region 2 in the variable region of immunoglobulin heavy chain CDR-H3 Complementary determining region 3 in the variable region of immunoglobulin heavy chain CDR-L1 Complementary determining region 1 in the variable region of immunoglobulin light chain CDR-L2 Complementary determining region 2 in the variable region of immunoglobulin light chain CDR-L3 Complementary determining region 3 in the variable region of immunoglobulin light chain APTT Activated partial thromboplastin time CFA Complete Freund's adjuvant EC50 50% effective concentration FACS Flow cytometry technology IC50 50% inhibitory concentration IFA Incomplete Freund's adjuvant MFI Mean fluorescence intensity FXI Human coagulation factor XI FXIa Activated human coagulation factor XI RLU Relative light units In the present invention, unless otherwise specified, all technical terms and scientific terms used herein have the same meaning as generally understood by those skilled in the art. In addition, the experimental procedures such as cell culture methods, biochemistry, nucleic acid chemistry, immunology, etc. used herein are all established procedures widely used in the corresponding fields. In addition, for a better understanding of the present invention, definitions and explanations of related terms are given below.

[0153] As used herein, the terms "FXI protein", "FXI antigen", and "FXI" are used interchangeably and refer to factor XI coagulation proteins of various species. The terms "FXIa protein", "FXIa antigen", and "FXIa" are used interchangeably and refer to activated factor XI proteins of various species. The terms "FXI" and "FXIa" (and similar terms) include respective variants and variants of the native FXI protein and FXIa protein, and the variants and variants have an amino acid sequence substantially the same as the native primary structure (amino acid sequence) described herein.

[0154] In the context of the present invention, the terms "coagulation and coagulation cascade", "coagulation cascade model", and similar terms are well known, and the coagulation pathway refers to the process by which a proteolytic cascade results in the production of thrombin, which then converts soluble fibrinogen into fibrin, forming a blood clot. The various enzymes of this pathway exist in plasma in the form of zymogens (inactive forms), but when activated, they undergo proteolytic cleavage to release active coagulation factors. The process of thrombin production can be divided into three stages: the intrinsic pathway and the extrinsic pathway, and the final common pathway.

[0155] As used herein, the term "antibody" generally refers to an immunoglobulin molecule composed of two pairs of polypeptide chains, each pair having a light chain (LC) and a heavy chain (HC). The light chains of an antibody can be classified into κ (kappa) light chains and λ (lambda) light chains. The heavy chains may be classified into μ heavy chains, δ heavy chains, γ heavy chains, α heavy chains, or ε heavy chains, and thus the isotypes of antibodies are defined as IgM, IgD, IgG, IgA, and IgE, respectively. Among the light and heavy chains, the variable region and the constant region are connected by a "J" region of about 12 or more amino acids, and the heavy chain also includes a "D" region of about 3 or more amino acids. Each heavy chain is composed of a heavy chain variable region (VH) and a heavy chain constant region (CH). The heavy chain constant region is composed of three domains (CH1, CH2, and CH3). Each light chain is composed of a light chain variable region (VL) and a light chain constant region (CL). The light chain constant region consists of one domain of CL. The constant domains are not directly involved in the binding of the antibody to the antigen, but exhibit various effector functions such as mediating the binding of the immunoglobulin to host tissues or host factors, including various cells of the immune system (e.g., effector cells) and the first component (C1q) of the classical complement system. The VH region and the VL region can also be subdivided into hypervariable regions (called complementarity-determining regions (CDRs)) interspersed with more conserved regions (called framework regions (FRs)). Each VH and each VL consist of three CDRs and four FRs arranged in the following order from the amino terminus to the carboxy terminus: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The variable regions (VH and VL) of each heavy chain / light chain pair form an antigen-binding site, respectively. The amino acid assignments in each region or each domain may follow a numbering system such as IMGT, Kabat, Chothia, or AbM.

[0156] Unless the context clearly indicates otherwise, as used herein, when the term "antibody" is referred to, this term includes not only intact antibodies but also antigen-binding fragments of antibodies.

[0157] As used herein, the term "complementary determining region" or "CDR" refers to the amino acid residues in the variable region of an antibody that contribute to antigen binding. The precise boundaries of these amino acid residues can be defined according to various numbering systems known in the art, for example, the Kabat numbering system (Kabat et al., "Sequences of Proteins of Immunological Interest", 5th ed., Public Health Service, National Institutes of Health, Bethesda, Md., 1991), the Chothia numbering system (Chothia and Lesk (1987), J. Mol. Biol., 196:901-917; Chothia et al. (1989), Nature, 342:878-883), the IMGT numbering system (Lefranc et al., Dev. Comparat. Immunol., 27:55-77, 2003), or the AbM numbering system (Martin ACR, Cheetham JC, Rees AR, Proc Natl Acad Sci USA, 86:9268-9272, 1989). For a given antibody, one of ordinary skill in the art can identify the CDRs defined by each numbering system. Furthermore, one of ordinary skill in the art is well aware of the correspondence relationships between different numbering systems (see, for example, Lefranc et al., Dev. Comparat. Immunol., 27:55-77, 2003).

[0158] As used herein, the term "framework region" or "FR" residue refers to the amino acid residues in the variable region of an antibody other than the CDR residues defined above.

[0159] As used herein, the term "germline antibody gene" is an immunoglobulin sequence encoded by non-lymphocytes that has not undergone the processes that can result in gene rearrangement and maturation for the expression of a particular immunoglobulin. One advantage provided by various embodiments of the present invention stems from the recognition that germline antibody genes retain more important amino acid sequence structures that characterize individual animal species than mature antibody genes. Thus, when therapeutically applied to this species, germline antibody genes are less likely to be recognized as foreign by this species.

[0160] The term "antibody" is not limited to any particular method for making an antibody. For example, the term "antibody" includes recombinant antibodies, monoclonal antibodies, and polyclonal antibodies. Antibodies can be antibodies of different isotypes, such as IgG (e.g., IgG1, IgG2, IgG3, or IgG4 subtypes) antibodies, IgA1 antibodies, IgA2 antibodies, IgD antibodies, IgE antibodies, or IgM antibodies.

[0161] As used herein, the term "antigen-binding fragment" of an antibody refers to a polypeptide that is a fragment of a full-length antibody, such as a polypeptide that retains the ability to specifically bind to the same antigen to which the full-length antibody binds, and / or the ability to compete with the full-length antibody for specific binding to an antigen, and is also sometimes referred to as an "antigen-binding portion". Generally, reference is made to "Fundamental Immunology", Chapter 7 (edited by Paul, W., 2nd edition, Raven Press, NY (1989)), which is incorporated herein by reference in its entirety for all purposes. Antigen-binding fragments of antibodies may be produced by recombinant DNA techniques or by enzymatic or chemical cleavage of intact antibodies. Non-limiting examples of antigen-binding fragments include Fab, Fab’, F(ab’)2, Fd, Fv, dAb, and complementarity-determining region (CDR) fragments, single-chain antibodies (e.g., scFv), chimeric antibodies, diabodies, linear antibodies, nanobodies (the technology is by Domantis), domain antibodies (the technology is by Ablynx), and polypeptides of small fragments sufficient to have the specific antigen-binding ability of a full-length antibody. Engineering antibody variants are reviewed in Holliger et al., 2005; Nat Biotechnol, 23:1126-1136.

[0162] As used herein, the term "full-length antibody" refers to an antibody composed of two "full-length heavy chains" or "heavy chains" and two "full-length light chains" or "light chains", where a "full-length heavy chain" or "heavy chain" refers to a polypeptide chain consisting of, from the N-terminus to the C-terminus, a heavy chain variable region (VH), a heavy chain constant region CH1 domain, a hinge region (HR), a heavy chain constant region CH2 domain, and a heavy chain constant region CH3 domain; when the full-length antibody is an antibody of the IgE isotype, this also optionally includes a heavy chain constant region CH4 domain. Preferably, a "full-length heavy chain" is a polypeptide chain composed of VH, CH1, HR, CH2, and CH3 from the N-terminus to the C-terminus. A "full-length light chain" or "light chain" is a polypeptide chain composed of, from the N-terminus to the C-terminus, a light chain variable region (VL) and a light chain constant region (CL). The two pairs of full-length antibody chains are connected by a disulfide bond between CL and CH1 and a disulfide bond between the HRs of the two full-length heavy chains. The full-length antibodies of the present invention may be derived from a single species such as a human; they may also be chimeric antibodies or humanized antibodies. The full-length antibodies of the present invention each contain two antigen-binding sites formed by a pair of VH and VL, and the two antigen-binding sites specifically recognize / bind specifically to the same antigen As used herein, the term "Fd fragment" refers to an antibody fragment composed of a VH domain and a CH1 domain; the term "dAb fragment" refers to an antibody fragment composed of a VH domain (Ward et al., Nature, 341:544-546 (1989)); the term "Fab fragment" refers to an antibody fragment composed of a VL domain, a VH domain, a CL domain, and a CH1 domain; the term "F(ab’)2 fragment" refers to an antibody fragment containing two Fab fragments connected by a disulfide bridge in the hinge region; the term "Fab’ fragment" refers to a fragment obtained by reducing the disulfide bond connecting the two heavy chain fragments in an F(ab’)2 fragment, which consists of an intact light chain and a heavy chain Fd fragment (composed of a VH domain and a CH1 domain).

[0163] As used herein, the term "Fv fragment" refers to an antibody fragment composed of a VL domain and a VH domain of a single arm of an antibody. An Fv fragment is generally considered to be the smallest antibody fragment capable of forming a complete antigen-binding site. Generally, six CDRs are considered to confer antigen-binding specificity to an antibody. However, even a variable region (e.g., an Fd fragment containing only three antigen-specific CDRs) can still have an affinity lower than that of a complete binding site, but can recognize and bind to an antigen.

[0164] As used herein, the term "Fc fragment" refers to an antibody fragment formed by the second and third constant regions of the first heavy chain and the second and third constant regions of the second heavy chain of an antibody, which are joined via disulfide bonds. The Fc fragment of an antibody has many different functions but does not participate in binding to an antigen.

[0165] As used herein, the term "scFv" refers to a single polypeptide chain comprising a VL domain and a VH domain, where VL and VH are connected by a linker (see, for example, Bird et al., Science, 242:423-426 (1988); Huston et al., Proc. Natl. Acad. Sci. USA, 85:5879-5883 (1988); and Pluckthun, "Pharmacology of Monoclonal Antibodies", Vol. 113, Roseburg and Moore eds., Springer-Verlag, New York, pp. 269-315 (1994)). Such scFv molecules can have the general structure: NH2-VL-linker-VH-COOH, or NH2-VH-linker-VL-COOH. Suitable linkers according to the prior art consist of repeats of the amino acid sequence GGGGS, or variants thereof. For example, a linker having the amino acid sequence (GGGGS)4 can be used, but variants thereof can also be used (Holliger et al. (1993), Proc. Natl. Acad. Sci. USA, 90:6444-6448). Other linkers that can be used in the present invention are described by Alfthan et al. (1995), Protein Eng., 8:725-731; Choi et al. (2001), Eur. J. Immunol., 31:94-106; Hu et al. (1996), Cancer Res., 56:3055-3061; Kipriyanov et al. (1999), J. Mol. Biol., 293:41-56; and Roovers et al. (2001), Cancer Immunol. Optionally, a disulfide bond can also be present between the VH and VL of the scFv. As used herein, the term "di-scFv" refers to an antibody fragment formed by linking two scFvs.

[0166] As used herein, the term "diabody" refers to a case where the VH and VL domains are expressed in a single polypeptide chain, but the linker used is too short to allow pairing between the two domains of the same chain such that the domains are forced to pair with the complementary domains of another chain to create two antigen-binding sites (see, e.g., Holliger P. et al., Proc. Natl. Acad. Sci. USA, 90:6444-6448 (1993); and Poljak RJ et al., Structure, 2:1121-1123 (1994)).

[0167] Each of the foregoing antibody fragments retains the ability to specifically bind to the same antigen to which the full-length antibody binds and / or the ability to compete with the full-length antibody for specific binding to the antigen.

[0168] As used herein, the term "multispecific antibody" refers to an antibody with multiple different antigen-binding specificities, including, for example, bispecific antibodies, trispecific antibodies, and tetravalent antibodies. A "bispecific antibody" refers to an antibody with two different antigen-binding specificities formed by conjugating a first antibody (or fragment thereof) with a second antibody (or fragment thereof) or an antibody mimetic via a coupling arm, and the coupling methods include, but are not limited to, chemical reactions, gene fusions, protein fusions, polypeptide fusions, and enzymatic reactions. A trispecific antibody is an antibody with three different antigen-binding specificities, and a tetravalent antibody is an antibody with four different antigen-binding specificities.

[0169] As used herein, an "antibody mimetic" is a substance that specifically binds to an antigen, like an antibody, but does not have the structure of an antibody. Antibody mimetics are typically artificial peptides or artificial proteins with a molar mass of about 3 - 20 kDa, such as designed ankyrin repeat proteins (DARPins) and Affimers. A DARPin (designed ankyrin repeat protein) is linked to an IgG antibody, an scFv-Fc antibody fragment, or a combination thereof, as described in Chinese Patent Application No. 104341529A. An anti-IL-17a Affimer binds to an anti-IL-6R antibody, as described in International Publication No. 2015141862A1.

[0170] As used herein, "immunoglobulin" or "Ig" may refer to a class of proteins that function as antibodies. Antibodies expressed by B cells are sometimes called antigen receptors. The five members of this class of proteins are IgA, IgG, IgM, IgD, and IgE. In this case, IgG is the most effective immunoglobulin in agglutination, complement fixation, and other antibody responses, and is the most common circulating antibody that is important in defense against bacteria and viruses.

[0171] In this context, an antigen-binding fragment of an antibody (e.g., the antibody fragments described above) may be obtained from a given antibody (e.g., an antibody provided by the present invention) using conventional techniques known to those skilled in the art (e.g., recombinant DNA technology or enzymatic or chemical fragmentation methods), and can be screened for specificity in the same manner as the intact antibody is screened.

[0172] As used herein, the terms "monoclonal antibody" and "mAb" have the same meaning and may be used interchangeably, and refer to a group of highly homologous antibody molecules, i.e., antibodies or antibody fragments derived from a group of identical antibody molecules, excluding naturally occurring mutations that may occur spontaneously. Monoclonal antibodies have a high degree of specificity for a single epitope on an antigen. Polyclonal antibodies are referred to in contrast to monoclonal antibodies and typically contain at least two or more different antibodies, which typically recognize different epitopes on an antigen. In addition, the modifier "monoclonal" refers only to the characteristic of an antibody as being obtained from a highly homogeneous population of antibodies and should not be considered as requiring any particular method for the production of the antibody.

[0173] The monoclonal antibodies of the present invention can be prepared by various techniques such as hybridoma technology (see, for example, Kohler et al., Nature, 256:495, 1975), recombinant DNA technology (see, for example, U.S. Patent No. 4,816,567), or phage antibody library technology (see, for example, Clackson et al., Nature, 352:624-628, 1991; or Marks et al., J. Mol. Biol., 222:581-597, 1991).

[0174] For example, monoclonal antibodies can be prepared as follows. First, a mouse or other suitable host animal is immunized with an immunogen (with an adjuvant added if necessary). The method of injecting the immunogen or adjuvant is usually multi-point subcutaneous injection or intraperitoneal injection. The immunogen is pre-coupled with a specific, known protein such as serum albumin or soybean trypsin inhibitor to enhance the immunogenicity of the antigen in the host. The adjuvant can be Freund's adjuvant or MPL-TDM, etc. After the animal is immunized, the body will produce lymphocytes that secrete antibodies that specifically bind to the immunogen. In addition, lymphocytes can also be obtained by in vitro immunization. The lymphocytes of interest are recovered and fused with myeloma cells using a suitable fusogen such as PEG to obtain hybridoma cells (Goding, "Monoclonal Antibodies: Principles and Practice", pages 59-103, Academic Press, 1996). The hybridoma cells prepared above can preferably be inoculated into a suitable culture medium containing one or more substances capable of inhibiting the growth of the unfused parental myeloma cells. For example, in parental myeloma cells lacking hypoxanthine-guanine phosphoribosyltransferase (HGPRT or HPRT), the addition of HAT (hypoxanthine, aminopterin, and thymine) medium to the culture medium will inhibit the growth of HGPRT-deficient cells. Preferred myeloma cells should have a high fusion rate, stable antibody-secreting ability, and sensitivity to HAT culture medium. Among these, mouse myelomas such as the MOP-21 strain or MC-11 strain derived from mouse tumors (Salk Institute Cell Distribution Center, San Diego, Calif., USA), and the SP-2 / 0 cell line, or the X63-Ag8-653 cell line (American Type Cuture Collection, Rockville, Md., USA) are preferred for myeloma cells.In addition, the research has also reported on the use of human myeloma cell lines and human-mouse heteromyeloma cell lines for the preparation of human monoclonal antibodies (Kozbor, J. Immunol., 133:3001 (1984); Brodeur et al., "Monoclonal Antibodies Production Techniques and Applications", pp. 51-63, Marcel Dekker, Inc., New York, 1987). The culture medium for growing hybridoma cells is used to detect the production of monoclonal antibodies against specific antigens. Methods for determining the binding specificity of monoclonal antibodies produced by hybridoma cells include, for example, immunoprecipitation or in vitro binding assays such as radioimmunoassay (RIA), enzyme immunoassay (ELISA). For example, the affinity of a monoclonal antibody can be determined using the Scatchard assay described by Munson et al., Anal. Biochem., 107:220 (1980). After determining the specificity, affinity, and reactivity of the antibody produced by the hybridoma, the cell line of interest is subcloned by the standard limiting dilution method described in Goding, "Monoclonal Antibodies: Principles and Practice", pp. 59-103, Academic Press, 1996. Suitable culture media can be DMEM or RPMI-1640, etc. In addition, hybridoma cells can also be grown in animals in the form of ascites tumors. Monoclonal antibodies secreted from subcloned cells can be isolated from cell culture media, ascites, or serum using conventional immunoglobulin purification methods such as protein A agarose gel, hydroxyapatite chromatography, gel electrophoresis, dialysis, or affinity chromatography.

[0175] Monoclonal antibodies can also be obtained by genetic engineering recombinant methods. DNA molecules encoding the heavy chain gene and the light chain gene of a monoclonal antibody can be isolated from hybridoma cells by PCR amplification using nucleic acid primers that specifically bind to the heavy chain gene and the light chain gene of the monoclonal antibody. The obtained DNA molecules are inserted into an expression vector and then transfected into host cells (such as E. coli cells, COS cells, CHO cells, or other myeloma cells that do not produce immunoglobulins) and cultured under appropriate conditions to obtain the desired recombinant antibody.

[0176] Antibodies can be purified by known techniques such as affinity chromatography using Protein A or Protein G. A specific antigen (the target molecule recognized by the antibody) or its epitope is immobilized on a column, and immunospecific antibodies can be purified by immunoaffinity chromatography. For the purification of immunoglobulins, see, for example, D. Wilkinson (The Scientist, Scientist, Inc., Philadelphia Pa., Vol. 14, No. 8 (April 17, 2000), pp. 25-28).

[0177] As used herein, the term "mouse antibody" refers to an antibody prepared by screening, preparing the antibody, and purifying the antibody, following the selection of mouse hybridoma cells that can proliferate infinitely and secrete antibodies by fusing immunized mouse B cells with myeloma cells; or an antibody secreted by plasma cells formed by the differentiation and proliferation of B cells after the antigen has invaded the mouse body.

[0178] As used herein, the term "chimeric antibody" refers to an antibody in which a portion of its light chain and / or heavy chain is derived from one antibody (which may be from a specific species and may belong to a particular specific antibody class or subclass), and another portion of the light chain and / or heavy chain is derived from another antibody (which may be from the same or a different species and may belong to the same antibody class or subclass or a different antibody class or subclass), but nevertheless retains the binding activity to the antigen of interest (U.S. Patent No. 4,816,567 by Cabilly et al.; Proc. Natl. Acad. Sci. USA, 81: 6851 - 6855 (1984)). For example, the term "chimeric antibody" may include an antibody in which the variable regions of the heavy and light chains of the antibody are derived from a first antibody (e.g., a mouse antibody), while the constant regions of the heavy and light chains of the antibody are derived from a second antibody (e.g., a human antibody) (e.g., a human - mouse chimeric antibody).

[0179] As used herein, the term "humanized antibody" refers to a genetically engineered non - human antibody whose amino acid sequence has been modified to increase its homology to the sequence of a human antibody. Generally, all or part of the CDR regions of a humanized antibody are derived from a non - human antibody (the donor antibody), and all or part of the non - CDR regions (e.g., the FR of the variable region and / or the constant region) are derived from a human immunoglobulin (the acceptor antibody). Humanized antibodies typically retain the desired properties of the donor antibody, including but not limited to antigen specificity, affinity, reactivity, the ability to enhance immune cell activity, the ability to enhance the immune response, etc. The donor antibody can be an antibody derived from a mouse, rat, rabbit, or non - human primate (e.g., cynomolgus monkey) that has the desired properties (e.g., antigen specificity, affinity, reactivity, the ability to enhance immune cell activity, and / or the ability to enhance the immune response).

[0180] Humanized antibodies are particularly advantageous because they can not only retain the properties expected of non-human donor antibodies (e.g., mouse antibodies), but can also effectively reduce the immunogenicity of non-human donor antibodies (e.g., mouse antibodies) in human subjects. However, due to the problem of matching the CDRs of the donor antibody with the FRs of the acceptor antibody, the properties expected of humanized antibodies (e.g., antigen specificity, affinity, reactivity, ability to enhance immunocyte activity, and / or ability to enhance the immune response) are generally lower than those of non-human donor antibodies (e.g., mouse antibodies).

[0181] Accordingly, researchers in this field have conducted in-depth research on antibody humanization and have shown some progress (see, for example, Jones et al., Nature, 321:522-525 (1986); Reichmann et al., Nature, 332:323-329 (1988); Presta, Curr.Op.Struct.Biol., 2:593-596 (1992); and Clark, Immunol.Today, 21:397-402 (2000)). However, the prior art has not provided detailed guidance on how to fully humanize a donor antibody such that the resulting humanized antibody is highly humanized and also retains, to the greatest extent possible, the properties expected of the donor antibody. In order to obtain a humanized antibody that is highly humanized (e.g., with a humanization degree of at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%) and also retains the properties expected of a specific donor antibody, engineers need to conduct searches, explorations, and modifications on the specific donor antibody and expend a lot of creative effort.

[0182] In the present invention, in order to retain the characteristics of the donor antibody (e.g., antigen specificity, affinity, reactivity, ability to enhance immune cell activity, and / or ability to enhance immune response) in the humanized antibody as much as possible, the framework region (FR) of the humanized antibody of the present invention can include both amino acid residues of the human acceptor antibody and amino acid residues of the corresponding non-human donor antibody.

[0183] The chimeric antibody or humanized antibody of the present invention can be prepared based on the sequence of the mouse monoclonal antibody prepared above. DNA encoding the heavy chain and the light chain may be obtained from the target mouse hybridoma and can be manipulated using standard molecular biological techniques so as to contain non-mouse (e.g., human) immunoglobulin sequences.

[0184] To prepare a chimeric antibody, the variable regions of murine immunoglobulins can be linked to the constant regions of human immunoglobulins using methods known in the art (see, e.g., U.S. Patent No. 4,816,567 by Cabilly et al.). For example, DNA encoding VH is operably linked to another DNA molecule encoding a heavy chain constant region so as to obtain a full-length heavy chain gene. In the art, the sequences of human heavy chain constant region genes are known (see, e.g., Kabat, E.A. et al. (1991), "Sequences of Proteins of Immunological Interest", 5th ed., U.S. Department of Health and Human Services, NIH Publication No. 91-3242), and DNA fragments containing these regions can be obtained by standard PCR amplification. The heavy chain constant region can be the constant region of IgG1, IgG2, IgG3, IgG4, IgA, IgE, IgM, or IgD, but generally, preferably, it is the constant region of IgG1 or IgG4. For example, DNA encoding VL is operably linked to another DNA molecule encoding CL, the light chain constant region, so as to obtain a full-length light chain gene (as well as the light chain gene of Fab). In the art, the sequences of human light chain constant region genes are known (see, e.g., Kabat, E.A. et al. (1991), "Sequences of Proteins of Immunological Interest", 5th ed., U.S. Department of Health and Human Services, NIH Publication No. 91-3242), and DNA fragments containing these regions can be obtained by standard PCR amplification. The light chain constant region can be the κ constant region or the λ constant region, but generally, preferably, it is the κ constant region.

[0185] To prepare a humanized antibody, any method known in the art (see U.S. Patent No. 5,225,539 by Winter; U.S. Patents Nos. 5,530,101, 5,585,089, 5,693,762, and 6,180,370 by Queen et al.; and Lo, Benny, KC ed., "Antibody Engineering: Methods and Protocols", Vol. 248, Humana Press, New Jersey, 2004) can be used to graft mouse CDR regions onto human framework sequences. Alternatively, transgenic animals capable of producing a fully human antibody library without producing endogenous immunoglobulins can also be used after immunization. For example, homozygous deletion of the antibody JH (heavy chain joining) region gene in chimeric germline mutant mice results in complete inhibition of endogenous antibody production, and introduction of a human germline immunoglobulin gene array in such germline mutant mice has been reported to result in the production of human antibodies upon antigen administration (see, for example, Jakobovits et al., 1993, Proc. Natl. Acad. Sci. USA, 90:2551; Jakobovits et al., 1993, Nature, 362:255-258; Bruggermann et al., 1993, Year in Immunology, 7:33; and Duchosal et al., 1992, Nature, 355:258). Non-limiting examples of the above transgenic animals include a mini-locus of human immunoglobulin genes encoding non-rearranged human heavy chain (μ and γ) immunoglobulin sequences and non-rearranged κ light chain immunoglobulin sequences, and targeting mutations that inactivate the endogenous μ-chain locus and κ-chain locus (see, for example, Lonberg et al. (1994), Nature, 368(6474):856-859), the HuMAb mouse (Medarex, Inc.); or the "KM mouse (KM mouse)(TM)" (see International Patent Application Publication No. 02 / 43478) carrying a human heavy chain transgene and a human light chain transchromosome.Other methods of humanizing antibodies include phage display technology (Hoogenboom et al., 1991, J. Mol. Biol., 227:381; Marks et al., J. Mol. Biol., 1991, 222:581-597; Vaughan et al., 1996, Nature Biotech, 14:309).

[0186] As used herein, the term "degree of humanization" is an index used to assess the number of non-human amino acid residues in a humanized antibody. The degree of humanization of a humanized antibody can be evaluated, for example, by predicting the homology of the variable region sequence to the human V domain using DomainGapAlign on the IMGT website.

[0187] As used herein, "homologous antibody" refers to a variant of an antibody whose amino acid sequences contained in the heavy chain variable region and the light chain variable region are homologous to the amino acid sequences of the antibody or its antigen-binding fragment presented herein, and the variant retains the desired functional properties of the antibody of the present invention against FXI and / or FXIa.

[0188] In the art, sequence alignment methods for comparison are well known. Various procedures and alignment algorithms are described in Smith TF and Waterman MS, Adv. Appl. Math., 2:482, 1981; Higgins DG and Sharp PM, CABIOS, 5:151, 1989. Altschul SF et al., Nature Genet., 6:119, 1994 presents a detailed consideration of sequence alignment and homology calculations.

[0189] As used herein, the term "specific binding" is a non-random binding reaction between two molecules, such as the reaction between an antibody and the antigen to which it is directed. The strength or affinity of a specific binding interaction can be represented by the equilibrium dissociation constant (KD) or the 50% effective concentration (EC50) for the interaction.

[0190] The specific binding characteristics between two molecules can be determined using methods known in the art. One method involves measuring the rates of formation and dissociation of the antigen-binding site / antigen complex. Both the "association rate constant" (ka, or kon) and the "dissociation rate constant" (kdis or koff) can be calculated from the concentration and the actual rates of association and dissociation (see Malmqvist M, Nature, 1993, 361:186-187). The ratio of kdis / kon is equal to the dissociation constant K D (see Davies et al., Annual Rev Biochem, 1990, 59:439-473). The KD value, kon value, and kdis value can be measured in any effective manner. In certain embodiments, the dissociation constant can be measured using biolayer interferometry (BLI) (e.g., the Fortebio Octet method). Additionally, the dissociation constant can be measured by surface plasmon resonance (e.g., Biacore) or Kinexa.

[0191] As used herein, the term "vector" is a nucleic acid vehicle into which a polynucleotide can be inserted. When a vector enables the expression of a protein encoded by the inserted polynucleotide, the vector is referred to as an expression vector. A vector can be introduced into a host cell by transformation, transduction, or transfection such that the genetic material element carried by the vector is expressed in the host cell. Vectors are well known to those of ordinary skill in the art and include, but are not limited to, plasmids; phagemids; cosmids; artificial chromosomes such as yeast artificial chromosomes (YACs), bacterial artificial chromosomes (BACs), or P1-derived artificial chromosomes (PACs); bacteriophages such as λ phage or M13 phage, and animal viruses. Animal viruses that can be used as vectors include, but are not limited to, retroviruses (including lentiviruses), adenoviruses, adeno-associated viruses, herpesviruses (e.g., herpes simplex virus), poxviruses, baculoviruses, papillomaviruses, papovaviruses (e.g., SV40). A vector can contain various elements that control expression, including, but not limited to, promoter sequences, transcription initiation sequences, enhancer sequences, selection elements, and reporter genes. In addition, a vector can contain an origin of replication.

[0192] Expression vectors and cloning vectors contain nucleic acid sequences that enable the vector to be replicated in one or more selected host cells. Generally, in a cloning vector, this sequence is one that enables the vector to replicate independently of the host chromosomal DNA and includes an origin of replication or an autonomously replicating sequence. As used herein, the term "expression vector" is a vector that contains a recombinant polynucleotide containing an expression control sequence operably linked to a nucleotide sequence to be expressed. Expression vectors contain cis-acting elements sufficient for expression, although other elements for expression may be provided by the host cell or an in vitro expression system. Expression vectors include all expression vectors known in the art, such as cosmids, plasmids (e.g., naked plasmids or plasmids contained in liposomes), and viruses (e.g., lentiviruses, retroviruses, adenoviruses, and adeno-associated viruses).

[0193] As used herein, the term "host cell" is a cell into which a vector can be introduced, including but not limited to cells such as prokaryotic cells like Escherichia coli or Bacillus subtilis, fungal cells like yeast cells or Aspergillus, insect cells like Drosophila S2 cells or Sf9 cells, or animal cells like fibroblast cells, CHO cells, COS cells, NSO cells, HeLa cells, BHK cells, HEK293 cells, or human cells.

[0194] As used herein, the term "identity" is the degree of match between two polypeptides or between two nucleic acids. Two sequences for comparison have the same monomeric subunits of bases or amino acids at a particular site (e.g., each of two DNA molecules has adenine at a particular site, or each of two polypeptides has lysine at a particular site), then the two molecules are identical at this site. The percent identity between two sequences is a function of the number of identical sites shared by the two sequences × 100 over the total number of sites for comparison. For example, if 6 out of 10 sites of two sequences match, these two sequences have 60% identity. For example, the DNA sequences: CTGACT and CAGGTT share 50% identity (3 out of 6 sites match). Generally, the comparison of two sequences is performed to yield the maximum identity. Such an alignment can be performed by using a computer program such as the Align program (DNAstar, Inc.) based on the method of Needleman et al. (J. Mol. Biol., 48:443-453, 1970). The percent identity between two amino acid sequences can also be determined using the algorithm by E. Meyers and W. Miller (Comput. Appl. Biosci., 4:11-17 (1988)), incorporated into the ALIGN program (version 2.0), using the PAM120 weight residue table, a 12-gap length penalty, and a 4-gap penalty. In addition, the percent identity between two amino acid sequences can also be determined by the algorithm of Needleman and Wunsch (J. Mol. Biol., 48:444-453 (1970)), incorporated into the GAP program in the GCG software package (available at http: / / www.gcg.com), using the Blossum 62 matrix or PAM250 matrix, and gap weights of 16, 14, 12, 10, 8, 6, or 4, and length weights of 1, 2, 3, 4, 5, or 6.

[0195] As used herein, the term "conservative substitution" means an amino acid substitution that does not deleteriously affect or alter the properties expected of a protein / polypeptide containing the amino acid sequence, and an antibody variant obtained by conservative substitution retains the biological activity of its original sequence, such as specific binding to FXI or FXIa. For example, conservative substitutions can be introduced by standard techniques known in the art, such as site-directed mutagenesis and PCR-mediated mutagenesis. Conservative amino acid substitutions include substitutions in which an amino acid residue is replaced with another amino acid residue having a similar side chain, e.g., a residue that is physically or functionally similar (e.g., having chemical properties such as similar size, shape, charge, ability to form covalent or hydrogen bonds) to the corresponding amino acid residue. In the art, families of amino acid residues having similar side chains are defined. These families include amino acids having basic side chains (e.g., lysine, arginine, and histidine), amino acids having acidic side chains (e.g., aspartic acid, glutamic acid), amino acids having uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine, tryptophan), amino acids having nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, valine, phenylalanine, methionine), beta-branched side chains (e.g., threonine, valine, isoleucine), and amino acids having aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Thus, it is preferred to replace the corresponding amino acid residue with another amino acid residue from the same side chain family. Methods for identifying conservative substitutions of amino acids are well known in the art (see, e.g., Brummell et al., Biochem. 32:1180-1187 (1993); Kobayashi et al., Protein Eng., 12(10):879-884 (1999); and Burks et al., Proc. Natl Acad. Sci USA, 94:412-417 (1997), which are incorporated herein by reference).

[0196] The 20 conventional amino acids involved in this specification are represented in a defined manner. See, for example, "Immunology - A Synthesis" (2nd Edition, eds. E.S. Golub and D.R. Gren, Sinauer Associates, Sunderland, Mass. (1991)), which is incorporated herein by reference. In this disclosure, the terms "polypeptide" and "protein" have the same meaning and are used interchangeably. Also in this disclosure, amino acids are generally represented by one - letter and three - letter abbreviations known in the art. For example, alanine can be represented by A or Ala.

[0197] As used herein, the term "pharmaceutically acceptable carrier and / or excipient" refers to a carrier and / or excipient that is pharmacologically compatible and / or physiologically compatible with the subject and the active ingredient, and is well-known in the art (see, e.g., "Remington’s Pharmaceutical Sciences", edited by Gennaro AR, 19th edition, Pennsylvania: Mack Publishing Company, 1995), and includes, but is not limited to, pH adjusting agents, surfactants, adjuvants, ionic strength enhancers, diluents, osmotic pressure maintaining agents, absorption delaying agents, preservatives. For example, pH adjusting agents include, but are not limited to, phosphate buffers. Surfactants include, but are not limited to, cationic surfactants, anionic surfactants, or nonionic surfactants such as Tween-80. Ionic strength enhancers include, but are not limited to, sodium chloride. Preservatives include, but are not limited to, various antibacterial and antifungal agents such as parabens, chlorobutanol, phenol, sorbic acid, etc. Osmotic pressure maintaining agents include, but are not limited to, sugars, NaCl, etc. Absorption delaying agents include, but are not limited to, monostearic acid and gelatin. Diluents include, but are not limited to, water, aqueous buffers (such as buffered saline), alcohol, and polyols (such as glycerin). Preservatives include, but are not limited to, various antibacterial and antifungal agents such as thimerosal, 2-phenoxyethanol, parabens, chlorobutanol, phenol, sorbic acid, etc. Stabilizers have the meaning generally understood by those skilled in the art and can stabilize the desired activity of the active ingredient in the drug, and include, but are not limited to, sodium glutamate, gelatin, SPGA, sugars (such as sorbitol, mannitol, starch, sucrose, lactose, dextran, or glucose), amino acids (such as glutamic acid, glycine, etc.), proteins (such as dried whey, albumin, or casein, etc.), or degradation products thereof (such as lactalbumin hydrolysate, etc.).

[0198] As used herein, the term "prevention" refers to a method implemented to prevent or delay the occurrence of a disease or disorder or symptom (e.g., a disease or disorder associated with coagulation or thromboembolism) in a subject. As used herein, the term "treatment" refers to a method implemented to obtain a beneficial clinical outcome or a desired clinical outcome. For the purposes of the present invention, a beneficial clinical outcome or a desired clinical outcome, whether detectable or undetectable, includes, but is not limited to, alleviation of symptoms, reduction of the scope of the disease, stabilization of the disease state (i.e., not worsening any further), delay or slowing of the onset of the disease, improvement or alleviation of the disease situation, and alleviation (partial or total) of symptoms, alleviation or improvement of the prognosis, reduction or suppression of the recurrence of the disease. In addition, the term "treatment" may also refer to an extension of the survival time as compared to the expected survival time (if not treated).

[0199] As used herein, the term "subject" refers to a mammal, such as a primate mammal such as a human. In certain embodiments, the subject (e.g., a human) suffers from, or is at risk of suffering from, a disease or disorder associated with coagulation or thromboembolism.

[0200] As used herein, the term "effective amount" refers to an amount sufficient to obtain, or at least partially obtain, a desired effect. For example, an effective amount for inhibiting a disease (e.g., a disease or disorder associated with coagulation or thromboembolism) refers to an amount sufficient to prevent, halt, or delay the onset of the disease (e.g., a disease or disorder associated with coagulation or thromboembolism); a therapeutically effective amount refers to an amount sufficient to cure, or at least partially prevent, a disease and its complications in a patient already suffering from the disease. Determining such an effective amount is entirely within the ability of one of ordinary skill in the art. For example, the effective amount for therapeutic use will depend on factors such as the disease being treated, the overall state of the patient's immune system, age, weight, and gender, the general condition of the patient, the route of administration of the drug, and other treatments being administered simultaneously.

[0201] As used herein, the term "effector function" refers to a biological activity attributable to the Fc region of an antibody (the Fc region of a natural sequence or a variant amino acid sequence), which varies depending on the isotype of the antibody. Examples of antibody effector functions include, but are not limited to, binding affinity for Fc receptors, antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), antibody-dependent cellular phagocytosis (ADCP), downregulation of cell surface receptors (e.g., B cell receptors), activation of B cells, secretion of cytokines, half-life / clearance of antibodies and antigen-antibody complexes, etc. In the art, methods for modifying the effector function of an antibody are known, for example, by introducing mutations into the Fc region.

[0202] As used herein, the term "antibody-dependent cell-mediated cytotoxicity (ADCC)" refers to a form of cytotoxicity in which cytotoxic effector cells specifically bind to target cells conjugated with an antigen through the binding of an immunoglobulin to an Fc receptor (FcR) presented on the cytotoxic cells (e.g., natural killer (NK) cells, neutrophils, or macrophages), and then kill the target cells by secreting cytotoxins. In the art, methods for detecting the ADCC activity of an antibody are known and can be assayed, for example, by measuring the binding activity of the test antibody to an Fc receptor (e.g., CD16a).

[0203] As used herein, the term "complement-dependent cytotoxicity (CDC)" refers to a form of cytotoxicity in which the complement cascade is activated by the binding of a complement component, Cq, to the Fc of an antibody. In the art, methods for detecting the CDC activity of an antibody are known and can be assayed, for example, by measuring the binding activity of the test antibody to an Fc receptor (e.g., C1q).

[0204] As used herein, the term "mediated by FXI and / or FXIa" means that FXI and / or FXIa directly or indirectly activate factor IX of blood coagulation (also known as FIX), factor X of blood coagulation (FX), and / or thrombin, and / or bind to platelet receptors, thereby mediating the intrinsic coagulation pathway.

[0205] As used herein, the term "disease or disorder associated with coagulation or thromboembolism" or similar terms refers to a disease or disorder caused by abnormal activation or non-natural inactivation (e.g., in the absence of therapeutic means) of the coagulation pathway. Such diseases or disorders include, but are not limited to, thrombosis, thrombotic stroke, atrial fibrillation, stroke prevention associated with atrial fibrillation (SPAF), deep vein thrombosis, venous thromboembolism, acute coronary syndrome (ACS), ischemic stroke, acute limb ischemia, chronic thromboembolic pulmonary hypertension, systemic embolism, myocardial infarction (MI), acute myocardial infarction (AMI), stable angina, unstable angina, restenosis and reocclusion after coronary intervention, peripheral arterial occlusive disease (PAOD), renal vein thrombosis, transient ischemic attack (TIA), pulmonary thromboembolism, disseminated intravascular coagulation, thromboembolic disorders caused by medical devices (e.g., catheters), severe systemic inflammatory response syndrome, metastatic cancer, infectious diseases, organ failure (e.g., renal failure), toxicity caused by administration of therapeutic proteins in the body, multiple trauma, ischemia-reperfusion injury, local fibrin deposition, adult respiratory distress syndrome, venous thromboembolic events (VTE) before and after total knee arthroplasty (TKA), coronary heart disease, thromboembolism after myocardial infarction, stroke in patients with non-valvular atrial fibrillation, thrombosis and thromboembolism in chronic kidney disease, thrombosis and thromboembolism in patients undergoing hemodialysis and extracorporeal membrane oxygenation, deep vein thrombosis (DVT), or pulmonary embolism (PE).

[0206] Catheter-induced thromboembolic disorders include the formation of thromboembolism in catheters (for example, the use of Hickman catheters in cancer patients and the use of extracorporeal membrane oxygenation (ECMO) can result in blood clots).

[0207] As used herein, the expression "prevention and / or treatment of a disease or disorder associated with coagulation or thromboembolism" refers to an antibody against FXI and / or FXIa, or an antigen-binding fragment thereof, according to the present invention, for one or more of the following diseases or disorders: Thromboembolism in an individual suspected or confirmed to have an arrhythmia such as paroxysmal, persistent, or permanent atrial fibrillation or atrial flutter; Stroke prevention in atrial fibrillation (SPAF) in a subgroup of AF patients undergoing percutaneous coronary intervention (PCI); Treatment of acute venous thromboembolic events (VTE) and prevention of recurrence of secondary VTE in patients at high risk of bleeding; Cerebral and cardiovascular events in secondary prevention after a transient ischemic attack (TIA) or a non-disabling stroke, and prevention of thromboembolic events in heart failure with sinus rhythm; Formation of blood clots and thromboembolism in the left atrium of an individual receiving defibrillation for arrhythmia; Thrombosis before, during, and after an excision procedure for arrhythmia; Treatment and secondary prevention of venous thrombosis, including deep vein thrombosis or superficial vein thrombosis, abdominal vein thrombosis and thoracic vein thrombosis, venous sinus thrombosis, and jugular vein thrombosis, in the lower or upper part (including and not excluding these); Thrombus on any artificial surface of an intravenous catheter or pacemaker lead; Pulmonary embolism in patients with or without venous thrombosis; Chronic thromboembolic pulmonary hypertension (CTEPH); Arterial thrombi in ruptured atherosclerotic plaques, thrombi in arterial assist devices or catheters, and thrombi in seemingly normal arteries, such diseases include, but are not limited to, acute coronary syndrome, ST-elevation myocardial infarction, non-ST-elevation myocardial infarction, unstable angina, stent thrombosis, thrombi on any artificial surface in the arterial system, and thrombi in the pulmonary arteries of patients with or without pulmonary hypertension; Thrombosis and thromboembolism in patients undergoing percutaneous coronary intervention (PCI); Cardiogenic stroke and cryptogenic stroke; Thrombosis in patients with invasive cancer malignancies and non-invasive cancer malignancies; Thrombi in indwelling catheters; Thrombosis in patients with severe diseases; Cardiac thrombosis after myocardial infarction, and cardiac thrombosis and cardiac thromboembolism including, but not exclusively, cardiac thrombosis associated with conditions such as cardiac aneurysms, myocardial fibrosis, cardiac hypertrophy and heart failure, myocarditis, and artificial surfaces in the heart; Thromboembolism in patients with valvular heart disease with or without atrial fibrillation; Thromboembolism in valve mechanisms or biological aids; Thromboembolism in patients with natural or artificial heart patches, arterial or venous catheters after heart repair of simple or complex congenital heart defects; Venous thrombosis and thromboembolism after artificial knee joint replacement, artificial hip joint replacement, and orthopedic, thoracic or abdominal surgery; Arterial or venous thrombosis after neurosurgery including intracranial intervention and spinal cord intervention; Congenital or acquired thrombotic tendencies, including, but not limited to, factor V Leiden mutation, prothrombin mutation, antithrombin III, protein C, and protein S deficiencies, factor XIII coagulation factor mutation, familial afibrinogenemia, congenital plasminogen deficiency, increased factor XI coagulation factor content, sickle cell disease, antiphospholipid syndrome, autoimmune diseases, chronic intestinal diseases, nephrotic syndrome, hemolytic anemia, myelodysplastic diseases, disseminated intravascular coagulation, paroxysmal nocturnal hemoglobinuria, and heparin-induced thrombocytopenia; Thrombosis and thromboembolism in chronic kidney disease; and Thrombosis and thromboembolism in patients receiving hemodialysis and patients receiving extracorporeal membrane oxygenation which may refer to use for the prevention or treatment of.

[0208] As used herein, the term "pharmaceutically acceptable" means that the molecule itself, molecular fragment, or composition does not produce an adverse reaction, allergic reaction, or other undesirable reaction when appropriately administered to an animal or human. Detailed examples of some substances that can be used as pharmaceutically acceptable carriers or components thereof include sugars such as lactose, starch, cellulose and its derivatives, vegetable oils, gelatin, polyols such as propylene glycol, alginic acid, and the like.

[0209] As used herein, combination therapy includes using an antibody against FXI and / or FXIa of the present invention, or an antigen-binding fragment thereof, in combination with one or more of a further active therapeutic agent (e.g., a chemotherapeutic agent) for a second treatment, or another prophylactic or therapeutic modality (e.g., an antiplatelet agent, an anticoagulant, a thrombolytic agent).

[0210] Exemplary antiplatelet agents for a second treatment are selected from aspirin, clopidogrel, prasugrel, ticagrelor, abciximab, eptifibatide, vorapaxar, or any combination thereof.

[0211] Exemplary anticoagulants for a second treatment are selected from unfractionated heparin, heparin, low molecular weight heparin, warfarin, fondaparinux, edoxaban, betrixaban, rivaroxaban, apixaban, dabigatran etexilate, argatroban, bivalirudin, or any combination thereof.

[0212] Exemplary thrombolytics for a second treatment are selected from streptokinase, urokinase, alteplase, or prourokinase.

[0213] In this type of combination therapy, the various active agents often have different complementary mechanisms of action, and the combination therapy can result in a synergistic effect. The combination therapy can allow for a reduction in the dosage of one or more of the agents so as to reduce or eliminate adverse effects associated with one or more of the agents. Such types of combination therapy can have a synergistic therapeutic or prophylactic effect on a potential disease, disorder, or condition.

[0214] As used herein, "combination" includes treatments that can be administered individually, such as individually formulated separate administrations (e.g., provided by one kit), and treatments that can be administered together as a single formulation (i.e., "co-formulation"). In certain embodiments, an antibody against FXI and / or FXIa, or an antigen-binding fragment thereof, according to the present invention can be administered sequentially. In other embodiments, an antibody against FXI and / or FXIa, or an antigen-binding fragment thereof, can be administered simultaneously. An antibody against FXI and / or FXIa, or an antigen-binding fragment thereof, according to the present invention can be used in any combination with at least one other (active) agent.

[0215] As used herein, the term "about" is ± 10% of the value stated in the context.

[0216] Since Chinese grammar does not have the singular and plural rules in English, when translating this disclosure into English, "one or more" can be added before a noun.

[0217] In the following, embodiments of the present invention will be described in detail together with the accompanying drawings and examples. However, those skilled in the art will understand that the following drawings and examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Various objects and advantageous aspects of the present invention will be feasible to those skilled in the art according to the accompanying drawings and the following detailed description of the preferred embodiments.

[0218] Array information Information about the arrays involved in the present invention is described in the following table. TIFF2025102802000001.tif225149

Example

[0219] Here, while referring to the following examples, which are intended to illustrate rather than limit the scope of the present invention, the present invention will be described.

[0220] Unless otherwise specified, the molecular biology experimental methods and immunoassay methods used in the present invention basically refer to the molecular biology experimental methods and immunoassay methods described in J. Sambrook et al., "Molecular Cloning: Laboratory Manual", 2nd edition, Cold Spring Harbor Laboratory Press, 1989; and F.M. Ausubel et al., "Short Protocols in Molecular Biology", 3rd edition, John Wiley & Sons, Inc., 1995. Those skilled in the art are aware that the examples are described for the purpose of illustration of the present invention and are not intended to limit the scope protected by the present invention.

[0221] Example 1: Preparation of Mouse Anti-Human FXI / FXIa Monoclonal Antibody Mouse anti-human FXI / FXIa monoclonal antibodies were obtained by immunizing wild-type Balb / c mice using proteins. For the first immunization, each Balb / c mouse was subcutaneously injected with 25 μg of human FXIa (manufacturer: Haematologic Technologies, catalog number: HCXI-0150) and 25 μg of human FXI (manufacturer: Haematologic Technologies, catalog number: HCXI-0160) emulsified with CFA (Complete Freund's Adjuvant, manufacturer: Sigma, catalog number: F5506). Immunization by booster administration was performed once every two weeks. In this case, for immunization by booster administration, an emulsion prepared with IFA (Incomplete Freund's Adjuvant, manufacturer: Sigma, catalog number: F5881) was used. After three rounds of immunization, the serum titer was measured by ELISA. For 3 to 5 days before fusion, immunization by booster administration was carried out, and mice with high titers were selected for intraperitoneal immunization with 10 μg of FXIa and 10 μg of FXI. A standard fusion procedure was adopted to fuse mouse spleen cells with Sp2 / 0-Ag14 (ATCC, catalog number: CRL-1581) mouse myeloma cells using the PEG fusion method. Then, HAT (manufacturer: Sigma, catalog number: H0262-10VL) was used for stress screening, and 14 days later, ELISA screening was performed. The detailed method for ELISA screening included the following: ELISA plates (manufacturer: Thermo Fisher Sci., catalog number: 5129) were coated at room temperature for 1 hour with 100 μL per well of 0.5 μg / mL biotinylated FXI (manufacturer: Haematologic Technologies, catalog number: HCXI-0150-B). Washing was performed three times using 200 μL of washing buffer (1× concentration of TBS containing 0.05% Tween-20). 100 μL of hybridoma supernatant was added and incubated at 37°C for 1 hour. Washing was performed three times using 200 μL of washing buffer. 100 μL of streptavidin-HRP (Pierce, catalog number: 21130) diluted at a ratio of 1:8000 was added and incubated at 37°C for 1 hour.Using 200 μL of washing buffer, washing was performed three times, 100 μL of TMB (purchased from Thermo Fisher Sci., model number: TMBW-1000-01) was added, and color development was carried out in the dark for 10 minutes. Then, 100 μL of stop solution (purchased from Thermo Fisher Sci., model number: 13361-100-10) was added, and reading was performed at 450 nm using a microplate reader.

[0222] The supernatants of 24,000 hybridoma clones were screened by ELISA, and 100 hybridoma clones capable of recognizing biotinylated FXI were obtained and transferred to 24-well plates. After 7 - 10 days, the hybridoma supernatants were examined by the APTT assay. The best clone 22 was subcloned by the limiting dilution method to obtain monoclonal hybridomas. Monoclonal hybridomas were examined for their anticoagulant activities by the APTT assay via an activated partial thromboplastin time (APTT) kit (activated partial thromboplastin time kit, manufacturer: Thermo Fisher Sci, model number: 100402). The detailed steps were as follows: 100 μL of normal human plasma (purchased from Innovative Research, model number: IPLA-N) was added to a pre-heated test tube, then 100 μL of APTT reagent (purchased from Thermo Fisher Sci., model number: 100402TS) and 100 μL of the test sample were added, mixed well, incubated at 37°C for 5 minutes, then 100 μL of calcium chloride (purchased from Thermo Fisher Sci.; model number: 100304, 20 mM) was added, the reading at OD405 was measured, and the clotting time was calculated by curve fitting. In this case, the Sp2 / 0-Ag14 cell supernatant was used as a negative control. 14E11 was used as a positive control antibody (prepared with reference to U.S. Patent No. US8388959B2, a patent by Aronora). The fold change shown in the APTT assay results was the ratio of the clotting time measured in the sample with the test antibody added to the clotting time measured in the antibody-free control sample. A fold change value of 1 or less indicated that the clotting time was neither delayed nor accelerated, while a fold change value greater than 1 indicated that the clotting time was prolonged.

[0223] As shown in Fig. 1, the hybridoma supernatants of a total of five subclones were examined by APTT. Here, since 36G9.10 showed an extended APTT time, it demonstrated a remarkable anticoagulant function and could be used for further analysis. In contrast, the other clones, 6B6.9, 28A8.3, 36C3, and 40F6.9, showed no significant difference in clotting time compared to the negative control. By the same screening method, 7B2, a hybridoma with an extended APTT time, was obtained for further analysis.

[0224] The monoclonal hybridomas 36G9.10 and 7B2 were expanded to 100 - 150 mL of the culture without serum. The supernatants were purified by Protein G, and when the purified mouse antibodies were detected by HPLC-SEC, their purities all exceeded 97%. The purified mouse antibodies could be used for further verification of function.

[0225] Example 2: Identification of the Function of Mouse Anti-Human FXI / FXIa Monoclonal Antibodies 2.1: Detection of the Function of Mouse Anti-Human FXI / FXIa Antibodies in Prolonging Coagulation Using the APTT detection method in Example 1, 36G9.10 was compared with the positive control antibody BAY-1213790 (prepared with reference to M007-H04 in International Patent Publication No. WO 2013 / 167669 by Bayer) and 14E11 under the condition that the antibody was diluted to have concentrations of 2.00, 1.00, 0.50, and 0.25 μg / mL, and PBS buffer was used as the negative control.

[0226] As shown in Fig. 2A, the candidate mouse antibody 36G9.10 showed a significant prolongation of the clotting time compared to the control antibodies BAY-1213790 and 14E11 at each concentration. Under the condition where the antibody concentration was 5 μg / mL, 7B2 was compared with the positive control antibody 14E11, and PBS buffer was used as the negative control. The results are shown in Fig. 2B. The candidate mouse antibody 7B2 showed a significant prolongation of the clotting time compared to PBS and showed a prolongation of the clotting time equivalent to that by the positive control antibody 14E11.

[0227] 2.2: Detection of the activity of mouse anti-human FXI / FXIa antibodies and their anticoagulant function that inhibit the catalysis of FXa production by FXIa According to the kit instructions, the BIOPHEN Factor XIa kit (HyphenBioMed, model number: 220412) was used in the detection, and the release of paranitroaniline (pNA) product was measured at OD405 nm to further confirm the activity of the anti-human FXI / FXIa antibody that inhibits the catalysis of FXa production by FXIa. All antibodies had a detection concentration of 0.25 μg / mL. The stronger the function of the anti-FXI / FXIa antibody to block FXI / FXIa activity, the smaller the signal value of the pNA product at OD405 nm.

[0228] The results are shown in Fig. 3. The 36G9.10 mouse antibody showed a significantly stronger anticoagulant function than the control antibodies BAY-1213790 and 14E11.

[0229] 2.3: Affinity test for mouse anti-human FXI / FXIa monoclonal antibodies Octet ForteBio® is widely used in detecting the antibody-antigen affinity kinetics. Using this, the affinity kinetics of the candidate mouse antibody 36G9.10, as well as the control antibodies BAY1213790 and 14E11, against FXIa were determined. The detailed experimental steps were as follows: First, the streptavidin biosensor was conjugated with the biotinylated test antibody to reach a response signal value of 0.8 nm, then it was conjugated with FXIa protein (3.2, 1.6, 0.8, 0.4, 0.2, 0.1, 0.05, and 0 μg / mL) for 5 minutes, and then dissociation was carried out for 7 minutes. A bivalent analysis model was used for all fitting analyses.

[0230] As shown in Table 1, 36G9.10 showed a binding rate (indicated by the Kon value) faster than that of the control antibodies 14E11 and BAY-1213790, a dissociation rate (indicated by the Kdis value) slower than that of BAY-1213790, and an affinity 1.7 and 2.5 times that of the control antibodies 14E11 and BAY-1213790, respectively. TIFF2025102802000002.tif46149

[0231] 2.4: Mouse anti-human FXI / FXIa antibody specifically blocks the biological activities of FXI and FXIa To confirm that the mouse antibody 36G9.10 specifically blocked the biological activities of FXI and FXIa, human plasma lacking FXI (purchased from Innovative Research, catalog number: 50-643-396) was used, and the APTT clotting time was determined by adding FXI (0.2, 0.4, 0.8 μg / mL), FXIa (0.2, 0.4, 0.8 μg / mL), FXI (0.4 μg / mL), and 36G9.10 (0.4 μg / mL), FXIa (0.4 μg / mL) and 36G9.10 (0.4 μg / mL).

[0232] The results are shown in Figure 4. The addition of FXI or FXIa significantly shortened the clotting time of human plasma lacking FXI, showing a dose-dependent relationship. When the 36G9.10 mouse antibody was added, the fact that FXI and FXIa showed a significant prolongation of the clotting time indicates that the mouse antibody, 36G9.10, specifically inhibited the biological activities of FXI and FXIa.

[0233] Example 3: Identification of Subtypes and Amplification of Variable Regions of Mouse Anti-Human FXI / FXIa Antibodies To identify the antibody subtypes of candidate hybridoma clones, the Pierce Rapid Isotyping kit (Catalog No.: 26179, purchased from Thermo Fisher Sci.) was used to identify the antibody subtypes of the candidate clones 36G9.10 and 7B2. The identification results showed that the candidate clones had a heavy chain of the IgG1 subtype and a light chain of the kappa subtype.

[0234] Hybridoma cells were cultured to a number of approximately 8,000, the cells were lysed, and the first-strand cDNA synthesis was carried out by using a cDNA reverse transcription kit (product number: 18080-200, purchased from Thermo Fisher Sci.). Using a special primer, the VH gene and VK gene were amplified from the cDNA by PCR, the PCR product was purified by a DNA purification kit (product number: 28104, purchased from Qiagen), and ligated with a TOPO vector (product number: K457540, purchased from Thermo Fisher Sci.). Approximately 12 clones were picked for each ligation reaction and sequenced. The sequences were analyzed by a vector, NTI 11.5 (purchased from Thermo Fisher Sci.), and a 5.4.6 type sequencer (purchased from Genecodes) to obtain the variable region sequences and CDR sequences of the mouse anti-FXI / FXIa antibody shown in the sequence listing. Here, the 36G9.10 mouse antibody has a heavy chain variable region shown in SEQ ID NO: 1 and a light chain variable region shown in SEQ ID NO: 2; the 7B2 mouse antibody has a heavy chain variable region shown in SEQ ID NO: 29 and a light chain variable region shown in SEQ ID NO: 30. Furthermore, for each of 36G9.10 and 7B2, chimeric antibodies 36G9.10-hz00 and 7B2-hz00 were constructed, which were obtained by grafting the sequence of the heavy chain variable region of 36G9.10 or 7B2 to the mutant human IgG1 heavy chain constant region (N297A mutant) (SEQ ID NO: 21) and grafting the sequence of the light chain variable region of 36G9.10 or 7B2 to the human kappa light chain constant region (SEQ ID NO: 22).

[0235] Example 4: Humanization of Anti-Human FXI / FXIa Mouse Antibody The mouse antibodies 36G9.10 and 7B2 were humanized by a method of grafting CDRs. Briefly, humanization involves the following steps: comparing the amino acid sequences of mouse monoclonal antibodies with those of human germline antibodies to find sequences with a high degree of homology and excellent physical and chemical properties, and using this as the human germline framework sequence; analyzing and searching for the affinity of HLA-DR to select a human germline framework sequence with low affinity; and then grafting the six CDRs of the mouse antibody into the selected heavy and light chain framework sequences.

[0236] Specifically, the CDR regions of the heavy and light chains of the mouse antibodies 36G9.10 and 7B2 were grafted into the corresponding FRs, which are the humanized templates. For 36G9.10, the heavy chain humanized template is the human germline gene sequence IGHV1-2 * 02 (see IMGT accession number: X62106), and IGHV1-69-2 * 01 (see IMGT accession number: KF698734), and the light chain humanized template is the human germline gene sequence IGKV1-33 * 01 (see IMGT accession number: M64856), and IGKV1-16 * 01 (see IMGT accession number: J00248). For 7B2, the heavy chain humanized template is the human germline gene sequence IGHV1-69-2 * 01 (see IMGT accession number: KF698734), and the light chain humanized template is the human germline gene sequence IGKVV1-39 * 01 (see IMGT accession number: X59315).

[0237] Furthermore, by molecular docking using computer simulation technology to explore the spatial binding form, the variable region and the surrounding framework amino acid sequences were analyzed. By calculating the values of electrostatic force, van der Waals force, hydrophobicity, and entropy, the key amino acids that interact with factor XIa and can maintain the spatial structure in the amino acid sequence of the mouse antibody were analyzed, and these mouse amino acids were retained in the grafted antibody. That is, a series of back mutations were made to the FR region amino acid residues of the humanized template so that the humanized antibody could retain the antigen-binding ability of the mouse antibody as much as possible.

[0238] According to the above method, a total of five humanized antibodies were constructed based on the CDRs of the mouse antibody 36G9.10, and were named 36G9.10-hz43, 36G9.10-hz73, 36G9.10-hz74, 36G9.10-hz92, and 36G9.10-hz93, respectively. In this case, the heavy chain constant region of each antibody was the human IgG1 heavy chain constant region (N297A mutant) (SEQ ID NO: 21). Based on the CDRs of the mouse antibody 7B2, the humanized antibody 7B2-hz11 was constructed. In this case, the heavy chain constant region was the mutant human IgG1 heavy chain constant region (N297A mutant) (SEQ ID NO: 21). The light chain constant region sequences of the antibodies 36G9.10-hz73, 36G9.10-hz74, 36G9.10-hz43, 36G9.10-hz92, 36G9.10-hz93, and 7B2hz11 were SEQ ID NO: 22, but none of them had ADCC and CDC effects.

[0239] The amino acid sequences of the variable and constant regions of the humanized antibodies are shown in Table 2. TIFF2025102802000003.tif72149

[0240] Example 5: Determination of the Affinity of Anti-Human FXI / FXIa Antibodies Octet ForteBio (registered trademark) was used to determine the affinity of chimeric antibodies and humanized antibodies. The main steps for the determination were as follows: First, chimeric antibodies and humanized antibodies (at a concentration of 0.3 μg / mL) were immobilized onto an AHC (anti-human Fc) sensor, and then FXI was subjected to a 1:2 gradient dilution with an initial concentration of 3.2 μg / mL to determine the association and dissociation rates of the chimeric antibodies and humanized antibodies. The obtained data was analyzed by Octet data analysis software.

[0241] The results are shown in Table 3, which indicated that all of the chimeric antibody 36G9.10-hz00 and the humanized antibodies 36G9.10-hz43, 36G9.10-hz73, 36G9.10-hz74, 36G9.10-hz92, 36G9.10-hz93 had a KD with an affinity stronger than that of the positive control BAY-1213790. TIFF2025102802000004.tif77149

[0242] Example 6: Determination of the APTT anticoagulant activity, inhibition of the activity of FXIa that catalyzes the production of FXa, and anticoagulant function of chimeric anti-human FXI / FXIa antibodies and humanized anti-human FXI / FXIa antibodies An APTT coagulation test kit was used to detect the anticoagulant activity of the humanized antibodies, and the detailed detection method was shown in Example 1. The results are shown in Figure 5. The mean value and standard deviation were calculated by performing the determination four times. All of the chimeric antibody 36G9.10-hz00 and the humanized antibodies 36G9.10-hz43, 36G9.10-hz73, 36G9.10-hz74, 36G9.10-hz92, 36G9.10-hz93 showed an extension of the coagulation time greater than that of the positive control antibodies 14E11 and BAY-1213790.

[0243] The anticoagulant activity of the humanized antibody was detected using a Biophen Factor XIa kit (purchased from Aniara; model number: 220412), and the detailed method was shown in Example 2.

[0244] The detection results are shown in Fig. 6, where the chimeric antibody 36G9.10-hz00, the humanized antibodies 36G9.10-hz43, 36G9.10-hz73, 36G9.10-hz74, 36G9.10-hz92, 36G9.10-hz93, the antibody 14E11 and BAY-1213790 can all effectively reduce the production of FXa. The fact that the antibodies 36G9.10-hz43, 36G9.10-hz73, 36G9.10-hz92, 36G9.10-hz93 can more effectively reduce the production of FXa compared to the control antibodies 14E11 and BAY-1213790 indicates that they have excellent anticoagulant activity.

[0245] Example 7: Determination of the affinity of humanized anti-human FXI / FXIa antibodies for FXI / FXIa The affinity of 36G9.10-hz73 for human FXIa was detected using the ELISA method. The detailed steps were as follows: FXIa antigen (Haematologic Technologies, HCXIA-160) was diluted to 1 μg / mL with CBS coating solution (0.32 g of Na2CO3 and 0.59 g of NaHCO3 dissolved in deionized water and diluted to 200 mL), and 100 μL per well was coated with FXIa antigen at 4 °C overnight; the next day, the liquid in the well was discarded, and one wash was performed with 300 μL of PBS; 100 μL of PBS (containing 2% BSA, BOVOGEN, BSAS 1.0) was added and blocked at 37 °C for 2 hours; the antibodies 36G9.10-hz73 and BAY-1213790 were diluted with PBS (containing 2% BSA) (starting at 10 μg / mL, 4-fold dilution, 12 concentration points), 100 μL of this dilution was added to the corresponding well, and incubated at 37 °C for 2 hours; three washes were performed with 300 μL of PBST; the HRP-labeled goat anti-human secondary antibody (purchased from Jackson, 109-035-00) was diluted 1:10000 with PBS (containing 2% BSA), 100 μL of this dilution was added to the corresponding well, and incubated at 37 °C for 1 hour; five washes were performed with 300 μL of PBST; 100 μL of TMB chromogenic solution (purchased from BioPanda, TMB-S-004) was added to the corresponding well and allowed to develop color at room temperature for 20 minutes; the color development was stopped by adding 50 μL of 2N H2SO4, and readings at OD450 nm were taken using a microplate reader (purchased from MD; SpectraMax M2), and the results were imported into GraphPad Prism for curve fitting.

[0246] The experimental results are shown in Figure 7A. Here, the EC50, which is the affinity of 36G9.10-hz73 for FXIa, was 2.488 ng / mL, and the EC50, which is the affinity of BAY-1213790 for FXIa, was 6.163 ng / mL, indicating that 36G9.10-hz73 was better than BAY-1213790.

[0247] The affinity of 36G9.10-hz73 for human FXI was detected using the ELISA method. Here, FXI antigen (obtained by cloning the PMD-F11 plasmid purchased from Sino Biological into the PLVX-TRES-PURO vector and transfecting 293F cells for expression) was diluted to 1 μg / mL with the CBS coating solution, and coating was performed at 100 μL per well overnight at 4°C. The remaining steps were the same as those shown in the previous section, except that the initial concentration of the antibody was 0.37 μg / mL and 3-fold dilutions were made at 9 concentration points.

[0248] The experimental results are shown in Figure 7B. Here, the EC50, which is the affinity of 36G9.10-hz73 for FXI, was 9.68 ng / mL, and BAY-1213790 did not bind to FXI, indicating that 36G9.10-hz73 could simultaneously neutralize FXI and FXIa and perform a good anticoagulant function.

[0249] Example 8: Detection of an anti-human FXI / FXIa antibody that competes with a control antibody for binding to FXIa To determine whether 36G9.10-hz73, BAY-1213790, and 14E11 recognize the same epitope of FXIa, a competitive ELISA assay was used for detection. The detailed steps were as follows: The FXI antigen was diluted to 1 μg / mL with the CBS coating solution, and 100 μL per well was coated with the FXI antigen at 4 °C overnight; the next day, the liquid in the wells was discarded and washing was performed with 300 μL of PBS; 100 μL of PBS (containing 2% BSA) was added and blocking was carried out at 37 °C for 2 hours; the biotinylated 36G9.10-hz73 antibody was diluted to 10 ng / mL with PBS (containing 2% BSA), and this was used as the stock solution to dilute the antibodies BAY-1213790 and 14E11 to 10 μg / mL. 100 μL of this dilution was added to the corresponding wells. A 10 μg / mL 36G9.10-hz73 antibody was used as the positive control, a 10 ng / mL biotinylated 36G9.10-hz73 antibody was used as the negative control, and a blank control was also set. All of these were incubated at 37 °C for 2 hours; washing was performed 3 times with 300 μL of PBST; the HRP-streptavidin secondary antibody (purchased from Proteintech, SA00001-0) was diluted at a ratio of 1:3000 with PBS (containing 2% BSA), and 100 μL of this dilution was added to the corresponding wells and incubated at 37 °C for 1 hour; washing was performed 5 times with 300 μL of PBST; 100 μL of the TMB chromogenic solution (purchased from BioPanda, TMB-S-004) was added to the corresponding wells and color development was carried out at room temperature for 20 minutes; color development was stopped by adding 50 μL of 2N H2SO4, and readings at OD450nm were taken with a microplate reader (Spectramax M2 purchased from MD), and the results were imported into GraphPad Prism for plotting.

[0250] The experimental results are shown in Fig. 8. Here, the fact that BAY-1213790 and 14E11 did not compete with 36G9.10-hz73 for binding to FXIa indicates that the former two and 36G9.10-hz73 bind to different epitopes of FXIa.

[0251] Example 9: Inhibition of the catalytic action of FXIa on a substrate by anti-human FXI / FXIa antibodies In 1988, Shunichiro Kawabata et al. screened several FXIa-specific fluorescent labeling substances for the sensitive detection of human FIXa enzyme activity in vitro (for details, see Eur. J. Biochem., 172, 17-25 (1988)). Therefore, by detecting the catalytic cleavage of a specific fluorescent substrate (I-1575, Bachem) by human FXIa, the activity of human FXIa and the effective neutralization of FXIa by humanized anti-human FXI / FXIa antibodies were determined. The detailed steps were as follows: Human FXIa was diluted to 1 nM with a buffer containing 50 mM Tris / HCl, 100 mM NaCl, 5 mM CaCl2, and 0.1% BSA, and this was used as the stock solution. The antibodies BAY-1213790 and 14E11 were serially diluted at a concentration of 20 μg / mL and 14 concentration points with 4-fold dilution; 10 μL of the diluted antibody was added to each well of a 384-well plate (4514 purchased from Coring) and incubated at 37°C for 1 hour; after incubation, 10 μL of the fluorescent substrate I-1575 with a concentration of 2 μM was added to each well, mixed, and immediately measured with a microplate reader to continuously read the fluorescence value at 360 / 465 nm, which was imported into GraphPad Prism for curve fitting.

[0252] The experimental results are shown in Table 4. Here, the antibody 36G9.10-hz73 effectively inhibited the catalytic action of FXIa on the fluorescent substrate and had an IC50 of 26.215 ng / mL, while BAY-1213790 had an IC50 of 69.96 ng / mL, indicating that 36G9.10-hz73 was better than BAY-1213790. TIFF2025102802000005.tif32149

[0253] Example 10: Detection of the anticoagulant activity of anti-human FXI / FXIa antibodies by measuring the activated partial thromboplastin time (APTT) After adding the APTT reagent to anticoagulated plasma, the intrinsic coagulation pathway was activated to activate XI to XIa. As a result, an antibody targeting FXIa inhibited the activity of FXIa, thereby extending the APTT. Therefore, the anticoagulant activity of the humanized anti-human FXI / FXIa antibody was detected using the determination of APTT. The detailed steps were as follows: Venous blood was collected from each of humans, monkeys, dogs, rabbits, and rats, and for each species, 2 - 3 samples were taken. For each sample, 4 test tubes (1.8 ml per test tube) of blood were collected and subjected to anticoagulation treatment using 3.2% sodium citrate and centrifugation at 500×g for 10 minutes at 4°C. Then, the resulting plasma was collected and stored at 4°C for subsequent use (combining all the plasma of each sample); The test antibody was diluted with physiological saline at 3 concentration points starting from 1500 μg / mL, and the 10-fold concentrated mother liquor of the test antibody was used; At high concentration, for the sample detection system, 135 μl of plasma was collected and 15 μl of the test antibody mother liquor was added (i.e., the mother liquor of the test antibody was diluted 10-fold) to make 150 μl, and then the APTT was detected using a fully automated blood coagulation analyzer (CA1500 purchased from Sysmex); At low concentration, for the sample detection system, 67.5 μl of plasma was collected and 7.5 μl of the test antibody mother liquor was added (i.e., the mother liquor of the test antibody was diluted 10-fold) to make 75 μl, and then the APTT was detected using a fully automated blood coagulation analyzer.

[0254] The results of the experiment are shown in Fig. 9A. Here, all four test antibodies, 36G9.10-hz73, BAY-1213790, BMS-962212 (prepared with reference to J Med Chem., Dec. 14, 2017; 60(23):9703-9723; doi:10.1021 / acs.jmedchem.7b01171; Epub, Nov. 17, 2017), and 14E11 showed an extension of APTT in human plasma. 36G9.10-hz73 showed the best effect, with the APTT extension being 2.2-fold at 6 μg / mL, which was better than the effects of the other three antibodies. As shown in Figs. 9B-9E, while 36G9.10-hz73 extended the clotting time by APTT only in monkey plasma, BAY-1213790 extended the clotting time by APTT in monkey and rabbit plasma, and 14E11 extended the clotting time by APTT in monkey, rabbit, and rat plasma. This indicates that 36G9.10-hz73 was different from BAY-1213790 and 14E11 in terms of species cross-reactivity. Thus, it is speculated that 36G9.10-hz73 bound to an epitope of FXI / FXIa different from the epitopes to which BAY-1213790 and 14E11 bound.

[0255] The prothrombin time (PT) test mainly reflected the state of the extrinsic coagulation system. The fold change shown in the PT test results was the ratio of the clotting time measured in the sample with the test antibody added to the clotting time measured in the antibody-free control sample. A fold change value of 1 or less indicated that the clotting time was neither delayed nor accelerated, while a fold change value exceeding 1 indicated that the clotting time was extended.

[0256] Using the same treatment method as above, the effects of 36G9.10-hz73, BAY-1213790, BMS-962212, and 14E11 on PT were detected by a fully automated blood coagulation analyzer. The detection results are shown in Table 5. Here, even when all samples were at a concentration of 150 μg / mL (1 μM), the PT in five types of plasma was not prolonged (in terms of fold change) compared to the PBS control, indicating that these did not affect extrinsic coagulation and did not increase the risk of bleeding. TIFF2025102802000006.tif48149

[0257] Example 11: Detection of the accelerated stability of anti-human FXI / FXIa antibodies The antibody 36G9.10-hz73 was diluted with 20 mM His-HCl (histidine-hydrochloride buffer) (containing 0.03% Tween-20, pH 5.5) to a concentration of 11.5 mg / mL and allowed to stand at 40 °C and 25 °C for 14 days and 28 days, respectively. Then, using the APTT detection method in Example 4, the anticoagulant activity of the sample after acceleration was detected, and by SEC, the purity of the antibody after acceleration was detected.

[0258] The experimental results are shown in Figure 10 and Table 6. Here, the antibody 36G9.10-hz73, which was allowed to stand at 40 °C and 25 °C for 14 days and 28 days, respectively, showed no significant changes in anticoagulant activity and purity. TIFF2025102802000007.tif48149

[0259] Example 12: Detection of the pharmacokinetics (PK) and pharmacodynamics (PD) of anti-human FXI / FXIa antibodies To detect the PK and PD of 36G9.10-hz73 in vivo, different doses of the antibody 36G9.10-hz73 were administered to cynomolgus monkeys by single intravenous injection (IV) or subcutaneous injection (SC), and blood samples were collected at different time points to detect PK and APTT activities. The detailed dosing groups and doses are shown in Table 7. Here, the volume of a single intravenous injection or subcutaneous administration was 2 mL / kg, the site of intravenous injection was the limb vein, and the site of subcutaneous injection was the posterior neck. TIFF2025102802000008.tif41149

[0260] After completing blood collection at all time points, the antibody 36G9.10-hz73 was used as a standard substance, and a calibration curve for antibody concentration was drawn using the ELISA method in Example 7. By using the calibration curve under the same conditions, the blood concentration of the antibody 36G9.10-hz73 at each time point was determined. Finally, for curve fitting, the measured blood concentrations were imported into GraphPad Prism, and the PK of 36G9.10-hz73 in cynomolgus monkeys was calculated.

[0261] At the same time, immediately after each blood sampling, APTT was detected using the method in Example 10. Finally, for curve fitting, the data at all time points were imported into GraphPad Prism, and the PK of 36G9.10-hz73 in cynomolgus monkeys was calculated.

[0262] The PK results are shown in Table 8. Here, the intravenous injection of the 36G9.10-hz73 antibody at 3 mg / kg showed a half-life of 290.15 hours in cynomolgus monkeys, and the subcutaneous injection of the 36G9.10-hz73 antibody at 3 mg / kg showed a half-life of 188.02 hours in cynomolgus monkeys. The subcutaneous injection of the 36G9.10-hz73 antibody at 3 mg / kg showed a bioavailability of 94% ± 2% (n = 2). TIFF2025102802000009.tif51149

[0263] The detection results of PD showed that 36G9.10-hz73 could be used for intravenous injection and subcutaneous administration to achieve a good effect of prolonging APTT. As shown in Figure 11A, the dose-effect relationship between the two intravenous injection dose groups was clearly shown. Since the subcutaneous injection group at 3 mg / kg had the effect of prolonging APTT by about 1.3 times after 1008 hours, it showed a slightly better effect on the prolongation of APTT than the intravenous injection group; as shown in Figure 11B, the fact that the three dose groups did not prolong PT indicated that they had no effect on extrinsic coagulation. Therefore, the 36G9.10-hz73 antibody had a potential clinical advantage of not causing the risk of bleeding.

[0264] Although the detailed embodiments of the present invention have been described in detail, those skilled in the art will understand that various modifications and changes may be made to the details in accordance with all the disclosed teachings, and these changes are within the protection scope of the present invention. The whole of the present invention is given by the appended claims and any equivalents thereof.

Claims

1. An antibody or antigen-binding fragment thereof that can specifically bind to FXI and / or FXIa, (1) The heavy chain variable region (VH) and light chain variable region (VL) of the CDR are defined by the IMGT numbering system as follows: A heavy chain variable region (VH) comprising the following three CDRs: CDR-H1 consisting of the sequence of SEQ ID NO: 33, CDR-H2 consisting of the sequence of SEQ ID NO: 34, and CDR-H3 consisting of the sequence of SEQ ID NO: 35; and A light chain variable region (VL) containing three CDRs as follows: CDR-L1 consisting of the sequence of sequence number 36, CDR-L2 consisting of the sequence of sequence number 37, and CDR-L3 consisting of the sequence of sequence number 38; Or (2) The heavy chain variable region (VH) and light chain variable region (VL) of the CDR are defined by the AbM numbering system as follows: A heavy chain variable region (VH) comprising the following three CDRs: CDR-H1 consisting of the sequence of SEQ ID NO: 39, CDR-H2 consisting of the sequence of SEQ ID NO: 40 or 47, and CDR-H3 consisting of the sequence of SEQ ID NO: 41; and The following are three CDRs: CDR-L1 consisting of the sequence of sequence number 42, CDR-L2 consisting of the sequence of sequence number 43, and CDR-L3 consisting of the sequence of sequence number 44, including a light chain variable region (VL). An antibody or its antigen-binding fragment, including an antibody.

2. (a) VH consisting of the sequence shown in Sequence ID No. 29 or a sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity thereto; VL consisting of the sequence shown in Sequence ID No. 30 or a sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity thereto; (b) VH consisting of the sequence shown in SEQ ID NO: 31 or a sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity thereto, and VL consisting of the sequence shown in SEQ ID NO: 32 or a sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity thereto including, The antibody or antigen-binding fragment thereof as described in claim 1.

3. The antibody or antigen-binding fragment thereof according to claim 1 or 2, which is a mouse antibody, a chimeric antibody, or a humanized antibody.

4. The antibody or antigen-binding fragment according to any one of claims 1 to 3, further comprising a heavy chain constant region (CH) and a light chain constant region (CL) derived from human immunoglobulin.

5. The antibody or antigen-binding fragment thereof according to claim 4, wherein the heavy chain constant region is an IgG heavy chain constant region and the light chain constant region is a κ light chain constant region.

6. The antibody or its antigen-binding fragment comprises the heavy chain constant region (CH) shown in SEQ ID NO: 21, or a variant thereof, wherein the variant has up to 20 conservative amino acid substitutions compared to SEQ ID NO: 21; and / or The antibody or its antigen-binding fragment comprises the light chain constant region (CL) shown in SEQ ID NO: 22, or a variant thereof, wherein the variant has up to 20 conservative amino acid substitutions compared to SEQ ID NO:

22. The antibody or antigen-binding fragment thereof according to claim 4.

7. The antibody is (i) A sequence including the VH shown in SEQ ID NO: 31 and the heavy chain constant region (CH) shown in SEQ ID NO: 21; Or (ii) Sequences having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the sequence shown in (i). A heavy chain containing an amino acid sequence selected from; and (iii) A sequence comprising the VL sequence shown in SEQ ID NO: 32 and the light chain constant region (CL) shown in SEQ ID NO: 22; Or Sequences having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the sequences shown in (iv)(iii). A light chain containing an amino acid sequence selected from, An antibody or antigen-binding fragment thereof according to any one of claims 1 to 6.

8. The aforementioned antibodies belong to the following groups: (a) A heavy chain comprising VH shown in SEQ ID NO: 31 and a heavy chain steady region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 32 and a light chain steady region (CL) shown in SEQ ID NO: 22, (b) A heavy chain comprising VH shown in SEQ ID NO: 29 and the heavy chain steady region (CH) shown in SEQ ID NO: 21, and a light chain comprising VL shown in SEQ ID NO: 30 and the light chain steady region (CL) shown in SEQ ID NO: 22 An antibody or antigen-binding fragment thereof according to any one of claims 1 to 7, selected from any one of the following.

9. ScFv, Fab, Fab', F(ab') ２ An antibody or antigen-binding fragment thereof according to any one of claims 1 to 8, selected from Fv fragments, disulfide-linked Fv (dsFv), and diabodies.

10. To be marked, An antibody or antigen-binding fragment thereof according to any one of claims 1 to 9.

11. The following features: (a) FXI and / or FXIa, with a K of less than 100 nM Ｄ To join together; (b) FXI and / or FXIa with an EC of less than 500 nM ５０ To join together; (c) The binding to FXI and / or FXIa inhibits or blocks the binding of FXI and / or FXIa to the substrate, thereby prolonging the coagulation time; (d) The binding to FXI and / or FXIa inhibits or blocks the catalytic activity of FXI and / or FXIa on the substrate; (e) The binding to FXI and / or FXIa does not affect extrinsic coagulation; (f) Reduced ADCC activity and / or CDC activity; (g) Not having ADCC activity and / or CDC activity; (h) The binding to FXI and / or FXIa inhibits or blocks the formation of dimers of FXI and / or FXIa; (i) Binding to FXI and / or FXIa inhibits or blocks the formation of a complex between FXI and / or FXIa and high molecular weight kininogen (HK); (j) To bind to the catalytic domain of FXI and / or FXIa, and / or to induce a conformational change thereof; (k) Inhibiting or blocking the binding of FXI and / or FXIa to platelet receptors; or Any combination of (l)(a) to (k) An antibody or antigen-binding fragment thereof according to any one of claims 1 to 10, having at least one of the above.

12. An isolated nucleic acid molecule encoding an antibody or an antigen-binding fragment thereof, its heavy chain and light chain, or its heavy chain variable region and light chain variable region, according to any one of claims 1 to 11.

13. A vector comprising the isolated nucleic acid molecule described in claim 12.

14. A host cell comprising an isolated nucleic acid molecule according to claim 12, or a vector according to claim 13.

15. A method for preparing an antibody or an antigen-binding fragment thereof according to any one of claims 1 to 11, comprising the steps of: culturing a host cell according to claim 14 under conditions that enable the expression of the antibody or the antigen-binding fragment thereof; and recovering the antibody or the antigen-binding fragment thereof from the culture of the cultured host cell.

16. The present invention comprises an antibody or antigen-binding fragment thereof that can specifically bind to FXI and / or FXIa, as described in any one of claims 1 to 11, and another antibody or antigen-binding fragment thereof, or an antibody mimetic. Multispecific antibodies.

17. An antibody or antigen-binding fragment thereof that can specifically bind to FXI and / or FXIa, as described in any one of claims 1 to 11, comprising a conjugate portion, wherein the conjugate portion is a detection label or a therapeutic agent. Conjugate.

18. A pharmaceutical composition comprising an antibody or antigen-binding fragment thereof according to any one of claims 1 to 11, an isolated nucleic acid molecule according to claim 12, a vector according to claim 13, a host cell according to claim 14, a multispecific antibody according to claim 16, or a conjugate according to claim 17, and a pharmaceutically acceptable carrier and / or excipient.

19. The pharmaceutical composition according to claim 18, further comprising a further pharmaceutically active agent selected from antiplatelet agents, anticoagulants, or thrombolytic agents.

20. The pharmaceutical composition according to claim 19, wherein the further pharmaceutically active agent is aspirin, clopidogrel, prasugrel, ticagrelor, absiximab, eptifivatide, borapaxar, unfractionated heparin, heparin, low molecular weight heparin, warfarin, fondaparinux, edoxaban, betrixaban, rivaroxaban, apixaban, dabigatran etexylate, argatroban, bivalirudine, streptokinase, urokinase, alteplase, prourokinase, or any combination thereof.

21. In the subject, the following biological activities were observed: (a) To bind to the catalytic domain of FXI and / or FXIa, and / or to induce a conformational change thereof; (b) Inhibiting or blocking the binding of FXI and / or FXIa to the substrate; (c) Inhibiting or blocking the binding of FXI and / or FXIa to platelet receptors; (d) Inhibiting or blocking the binding of FXI to coagulation factor XIIa (FXIIa), thereby inhibiting or blocking the conversion of FXI to active FXIa; (e) Inhibiting or blocking the binding of FXIa to the coagulation factor FIX, thereby inhibiting or blocking the conversion of FIX to active FIXa; (f) Inhibiting or blocking the activation of the intrinsic coagulation pathway mediated by FXI and / or FXIa; (g) Inhibiting or blocking the activity of FXI and / or FXIa in thrombosis; (h) Prolonging the coagulation time mediated by FXI and / or FXIa; (i) Inhibiting thrombosis; (j) To prevent and / or treat diseases or disorders associated with coagulation or thromboembolism mediated by FXI and / or FXIa; or Any combination of (k)(a) to (j) The pharmaceutical composition according to claim 18, comprising the antibody or an antigen-binding fragment thereof in an effective dose sufficient to cause at least one of the following:

22. A pharmaceutical composition according to any one of claims 18 to 21, further comprising a second antibody or a nucleic acid encoding the second antibody, wherein the second antibody is another antibody capable of recognizing different epitopes of FXI or FXIa, or an antibody capable of specifically binding to a receptor or ligand selected from the group consisting of thrombin, antiplasmin, factor XII, factor VIII, factor VII, factor X, factor IX, factor II, tissue factor, P-selectin and its ligand, L-selectin and its ligand, or any combination of the above antibodies.

23. A kit comprising an antibody or antigen-binding fragment thereof according to any one of claims 1 to 11, or a vector according to claim 13, or a host cell according to claim 14, or a multispecific antibody according to claim 16, or a conjugate according to claim 17, or a pharmaceutical composition according to any one of claims 18 to 22, and instructions for use.

24. Use of an antibody or antigen-binding fragment thereof according to any one of claims 1 to 11, or an isolated nucleic acid molecule according to claim 12, or a vector according to claim 13, or a host cell according to claim 14, or a multispecific antibody according to claim 16, or a conjugate according to claim 17, or a pharmaceutical composition according to any one of claims 18 to 22, in the manufacture of a pharmaceutical for the prevention and / or treatment of a disease or disorder associated with coagulation or thromboembolism.

25. The following objectives: (a) To bind to the catalytic domain of FXI and / or FXIa, and / or to induce a conformational change thereof; (b) Inhibiting or blocking the binding of FXI and / or FXIa to the substrate; (c) Inhibiting or blocking the binding of FXI and / or FXIa to platelet receptors; (d) Inhibiting or blocking the binding of FXI to coagulation factor XIIa (FXIIa), thereby inhibiting the conversion of FXI to active FXIa; (e) Inhibiting or blocking the binding of FXIa to the coagulation factor FIX, thereby inhibiting the conversion of FIX to active FIXa; (f) Inhibiting or blocking the activation of the intrinsic coagulation pathway mediated by FXI and / or FXIa; (g) Inhibiting or blocking the activity of FXI and / or FXIa in thrombosis; (h) Prolonging the coagulation time mediated by FXI and / or FXIa; (i) Inhibiting thrombosis; (j) To prevent and / or treat diseases or disorders associated with coagulation or thromboembolism mediated by FXI and / or FXIa; or Any combination of (k)(a) to (j) The use of an antibody or antigen-binding fragment thereof according to any one of claims 1 to 11, or an isolated nucleic acid molecule according to claim 12, or a vector according to claim 13, or a host cell according to claim 14, or a multispecific antibody according to claim 16, or a conjugate according to claim 17, or a pharmaceutical composition according to any one of claims 18 to 22, in the manufacture of a pharmaceutical used for at least one of the above.

26. The aforementioned coagulation or thromboembolic-related diseases or disorders include thrombosis, thrombotic stroke, atrial fibrillation, atrial fibrillation-associated stroke prevention (SPAF), deep vein thrombosis, venous thromboembolism, acute coronary syndrome (ACS), ischemic stroke, acute limb ischemia, chronic thromboembolic pulmonary hypertension, systemic embolism, myocardial infarction (MI), acute myocardial infarction (AMI), stable angina, unstable angina, reocclusion and restenosis after coronary intervention, peripheral artery occlusive disease (PAOD), renal vein thrombosis, transient ischemic attack (TIA), pulmonary thromboembolism, diffuse intravascular coagulation, thromboembolic disorders caused by medical devices, and severe systemic inflammatory response syndrome. Use according to claim 24 or 25, selected from the group consisting of metastatic cancer, infectious diseases, organ failure, toxicity caused by administration of therapeutic proteins in the body, multiple trauma, ischemic-reperfusion injury, focal fibrin deposition, adult alveolar proteinosis, venous thromboembolic events (VTE) before and after total knee arthroplasty (TKA), coronary heart disease, thromboembolism after myocardial infarction, stroke in patients with non-valvular atrial fibrillation, thrombosis and thromboembolism in chronic kidney disease, thrombosis and thromboembolism in patients undergoing hemodialysis and patients undergoing extracorporeal membrane oxygenation, deep vein thrombosis (DVT), or pulmonary embolism (PE).

27. A method for detecting the presence or level of FXI and / or FXIa in a sample, comprising the steps of: contacting the sample with an antibody or antigen-binding fragment thereof, or a conjugate according to any one of claims 1 to 11, or according to claim 17, under conditions that enable the formation of a complex between the antibody or antigen-binding fragment thereof and FXI and / or FXIa; and detecting the formation of the complex.

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