ANTIBODIES AGAINST TISSUE FACTOR PATHWAY INHIBITORS AND THEIR USES

Abstract

The invention relates to antibodies,and antigen-binding fragments thereof,that specifically bind TFPI and inhibit an activity thereof. Such antibodies and fragments are useful for treating bleeding disorders and shortening clotting time.

Description

TISSUE FACTOR PATHWAY INHIBITOR ANTIBODIES AND USES THEREOFField of the Invention[1] This invention relates to antibodies that bind to Tissue Factor Pathway Inhibitor (TFPI).Background of the Invention[2] Hemophilia A and B are X-linked genetic disorders resulting from functional deficiencies of the plasma proteins Factor VIII (FVIII) or Factor IX (FIX), respectively. Clinical severity of hemophilia is related to the residual level of clotting factor activity. Factor activity of <1 % is associated with a severe phenotype, moderate hemophilia is associated with a factor activity of 2%-5% and mild with a factor activity 5%-40%.[3] The standard of care for these disorders is replacement of the missing coagulation factor through intravenous infusions. The replacement factor is commonly a recombinant protein, such as Xyntha (Factor VIII) or BeneFIX (FIX), but plasma derived products of various purity are still in use. Treatment with replacement factor can either be episodic, treating bleeds on demand as they occur, or prophylactic, preventing bleeds by maintaining factor levels in a protective range.Significant evidence exists that prophylactic treatment prevents bleeds and the associated joint damage that is the major morbidity in hemophilic patients. Effective prophylactic treatment requires intravenous injection of factor 3-4 times each week, which results in difficulties in compliance and reduced quality of life. The cost of treatment is also expensive due to the complexity ofmanufacture of coagulation factors. Furthermore, a significant number of patients, up to 32% of patients with severe Hemophilia A, develop neutralizing antibodies to the administered factors, which are seen as foreign proteins by patients who have mutations in these genes. These patients require alternative means of treatment such as the bypass factor, Factor Vila (NovoSeven).[4] An alternative approach to therapy is to bypass the need for replacement factors by augmenting the intact extrinsic pathway. Patients with hemophilia have some ability to stop bleeds through their intact extrinsic pathway; however this is not sufficient to shut down major bleeds or to prevent spontaneous bleeds. The extrinsic pathway is insufficient to provide protection because it is rapidly shut down by Tissue Factor Pathway Inhibitor (TFPI).[5] Although WO 2010 / 017196 (Bayer), WO 201 1 / 109452 (Bayer), WO 2014 / 144577 (Bayer), WO 2010 / 072687 (Novo Nordisk), WO 2012 / 001087 (Novo Nordisk), WO 2014 / 140240 (Novo Nordisk), and WO 2015 / 007880 (Novo Nordisk) disclose antibodies that bind to human TFPI, they do not provide the antibodies of the invention which have characteristics that make them novel potential therapeutics for hemophilia. [6] A product that would provide prophylactic protection while reducing the frequency of dosing of coagulation factors, reducing the quantity of use of factors, allowing alternative routes of delivery (e.g., subcutaneous) and having a lower risk of generating neutralizing antibodies, would fulfill a significant unmet need for patients with hemophilia.Summary of the Invention[7] Disclosed and exemplified herein are antibodies (and antigen-binding fragments thereof) that bind to the Tissue Factor Pathway Inhibitor (TFPI).[8] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein.Such equivalents are intended to be encompassed by the following embodiments (E).E1. An isolated antibody or antigen-binding fragment thereof, that specifically binds to an epitope in Kunitz Domain 2 (K2) of Tissue Factor Pathway Inhibitor (TFPI), wherein said epitope comprises residues Ile105, Arg107, and Leu131 , according to the numbering of SEQ ID NO: 2.E2. The antibody or antigen-binding fragment thereof of embodiment 1 , wherein said antibody, or antigen-binding fragment thereof, does not bind to Kunitz Domain 1 (K1) of TFPI.E3. The antibody or antigen-binding fragment thereof of embodiment 1 or 2, wherein said epitope further comprises one or more residues selected from the group consisting of: Cys106,Gly108, Cys130, Leu 131 , and Gly132, according to the numbering of SEQ ID NO: 2.E4. The antibody or antigen-binding fragment thereof of any one of embodiments 1-3, wherein said epitope further comprises residues Cys106, Gly108, Cys130, Leu131 , and Gly132, according to the numbering of SEQ ID NO: 2.E5. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4, wherein said epitope further comprises one or more residues selected from the group consisting of:Asp102, Arg1 12, Tyr127, Gly129, Met134, and Glu138, according to the numbering of SEQ ID NO: 2.E6. The antibody or antigen-binding fragment thereof of any one of embodiments 1-5, wherein said epitope further comprises Asp102, Arg1 12, Tyr127, Gly129, Met134, and Glu138, according to the numbering of SEQ ID NO: 2.E7. The antibody or antigen-binding fragment thereof of any one of embodiments 1-6, wherein said epitope does not comprise one or more residues selected from the group consisting of: E100, E101 , P103, Y109, T1 1 1 , Y1 13, F1 14, N116, Q1 18, Q121 , C122, E123, R124, F125, K126, and L140, according to the numbering of SEQ ID NO: 2. E8. The antibody or antigen-binding fragment thereof of any one of embodiments 1-7, wherein said epitope does not comprise: E100, E101 , P103, Y109, T1 11 , Y113, F1 14, N1 16, Q1 18, Q121 , C122, E123, R124, F125, K126, and L140, according to the numbering of SEQ ID NO: 2.E9. The antibody or antigen-binding fragment thereof of any one of embodiments 1-6, wherein said epitope does not comprise one or more residues selected from the group consisting of: D31 , D32, P34, C35, K36, E100, E101 , P103, Y109, K126, and G128, according to the numbering of SEQ ID NO: 2.E10. The antibody or antigen-binding fragment thereof of any one of embodiments 1-6 and 9, wherein said epitope does not comprise: D31 , D32, P34, C35, K36, E100, E101 , P103, Y109, K126, and G128,according to the numbering of SEQ ID NO: 2.E1 1. The antibody or antigen-binding fragment thereof of any one of embodiments 1-10, wherein said epitope comprises one or more residues selected from the group consisting of: Asp102, Gly104, Ile105, Cys106, Arg107, Gly108, Arg1 12, Tyr127, Gly129, Cys130, Leu131 , Gly132, Asn133, Met134, and Glu138 (according to the numbering of SEQ ID NO: 2), wherein said epitope residue has a non-zero change in buried surface area (BSA) due to interaction with said antibody or antigen-binding fragment thereof.E12. The antibody or antigen-binding fragment thereof of embodiment 1 1 , wherein said epitope comprises: Asp102, Gly104, Ile105, Cys106, Arg107, Gly108, Arg1 12, Tyr127, Gly129, Cys130, Leu131 , Gly132, Asn133, Met134, and Glu138 (according to the numbering of SEQ ID NO: 2). E13. The antibody or antigen-binding fragment thereof of any one of embodiments 1-12, wherein said epitope comprises one or more residues selected from the group consisting of:Asp102, Arg107, Arg 1 12, Tyr127, and Leu131 (according to the numbering of SEQ ID NO: 2), wherein said epitope residue participates in a hydrogen bond with a residue from said antibody or antigen-binding fragment thereof.E14. The antibody or antigen-binding fragment thereof of embodiment 13, wherein said epitope comprises: Asp102, Arg107, Arg 112, Tyr127, and Leu131 (according to the numbering of SEQ ID NO: 2).E15. The antibody or antigen-binding fragment thereof of any one of embodiments 1-14, wherein said epitope comprises one or more contact residues selected from the group consisting of:Asp102, Gly104, Ile105, Cys106, Arg107, Gly108, Arg1 12, Tyr127, Gly129, Cys130, Leu131 , Gly132, Met134, and Glu138 (according to the numbering of SEQ ID NO: 2). E16. The antibody or antigen-binding fragment thereof of embodiment 15, wherein said epitope comprises: Asp102, Gly104, Ile105, Cys106, Arg107, Gly108, Arg1 12, Tyr127, Gly129, Cys130, Leu131 , Gly132, Met134, and Glu138 (according to the numbering of SEQ ID NO: 2).E17. The antibody or antigen-binding fragment thereof of any one of embodiments 1-16, comprising the following heavy (H) chain and light (L) chain paratope residues that have a non-zero change in BSA due to interaction with TFPI (numbering according to Kabat): H33 Ala, H58 Tyr, H95 Leu, H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu, H100A Ser, L29 Ala, L31 Tyr, L91 Tyr, L95A Ser, and L95B Gly.E18. The antibody or antigen-binding fragment thereof of any one of embodiments 1-17, comprising the following contact residues (numbering according to Kabat): (a) H47 is Trp or Tyr; (b) H58 is Tyr; and (c) L91 is Tyr or Arg; and optionally comprising: (d) L96 is Gly or Asn.E19. The antibody or antigen-binding fragment thereof of any one of embodiments 1-18, comprising the following contact residues (numbering according to Kabat): (a) H33 is Ala, Asn, Gly, His, Lys, Met, Phe, Pro, Ser, Thr, Trp, or Val; (b) H47 is Trp or Tyr; (c) H50 is Ala, Arg, Gly, Lys, Met, Phe, Pro, Ser, Thr, Tyr, or Val; (d) H51 is lie, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; (e) H52 is Ser, Ala, Arg, Asn, Asp, Gin, Glu, Gly His, lie, Leu, Lys, Met, Phe, Pro, Ser, Trp, Tyr, or Val; (f) H56 is Ser, Arg, Gly, His, lie, Leu, Lys, Met, Phe, Pro, Ser, Thr, Trp, Tyr, or Val; (g) H58 is Tyr; (h) H95 is Leu, Gin, lie, Phe, or Tyr; (i) H96 is Gly, Ala, Arg, Asn Asp, Gin, lie, Lys, Met, Phe, Pro, Ser, Thr, or Val; (j) H97 is Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; (k) H98 is Thr, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; (I) H99 is Ser, Ala, Gly, Phe, or Pro; (m) H100 is Leu, Arg, His, lie, Leu, Lys, Phe, Pro, Trp, Tyr, or Val; (n) H100A is Ser, Ala, Arg, Asn Asp, Gin, Glu, His, Leu, Lys, Met, Phe Pro, Ser, Thr, or Trp; (o) L29 is Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, or Trp, Tyr, Val; (p) L31 is Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; (q) L91 is Tyr or Arg; (r) L95A is Ser, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; (s) L95B is Ser, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; and (t) L95C is Ser, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; and optionally comprising the following residues: (u) L93 is Tyr, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; and (v) L96 is Gly or Asn. E20. The antibody or antigen-binding fragment thereof of any one of embodiments 1-18, comprising the following contact residues (numbering according to Kabat): (a) H33 is Ala or Val; (b) H47 is Trp; (c) H50 is Ala; (d) H51 is lie; (e) H52 is Ser, Arg, Lys, Phe, or Tyr; (f) H56 is Ser, Arg, or Lys; (g) H58 is Tyr; (h) H95 is Leu; (i) H96 is Gly, Ala, Arg, Asn, Lys, Pro, Ser, or Val; (j) H97 is Ala; (k) H98 is Thr, His, lie, Leu, Met, Phe, or Tyr; (I) H99 is Ser; (m) H100 is Leu, Phe, Trp, or Tyr; (n) H100A is Ser, Arg, Asn, Gin, Glu His, Leu, Lys, Met, Phe, Pro, or Trp; (o) L29 is Ala; (p) L31 is Tyr; (q) L91 is Tyr; (r) L95A is Ser, Phe, Trp, or Tyr; (s) L95B is Gly; and (t) L95C is Ser, Arg, Asn, Gin, Glu, lie, Leu, Lys, Met, Phe, Trp, Tyr, or Val; and optionally comprising the following residues: (u) L93 is Ser; and (v) L96 is Gly.E21. The antibody or antigen-binding fragment thereof of any one of embodiments 1-18, comprising the following contact residues (numbering according to Kabat): (a) H33 is Ala, Val, His, or Phe; (b) H47 is Trp or Tyr; (c) H50 is Ala, Thr, Ser, or Phe; (d) H51 is lie, Arg, Lys, or Pro; (e) H52 is Ser, Phe, Arg, or Tyr; (f) H56 is Ser, Lys, Tyr, or Phe; (g) H58 is Tyr; (h) H95 is Leu, lie, Gin, or Phe; (i) H96 is Gly, Arg, Asn, or Lys; (j) H97 is Ala, Leu, Tyr, or lie; (k) H98 is Thr, Tyr, Phe, or His; (I) H99 is Ser, Pro, Ala, or Phe; (m) H100 is Leu, Tyr, Trp, or Phe; (n) H100A is Ser, Arg, Leu, or Trp; (o) L29 is Ala, Glu, Asp, or Gin; (p) L31 is Tyr, Glu, Asp, or Trp; (q) L91 is Ty or Arg; (r) L95A is Ser, Phe, Tyr, or His; (s) L95B is Gly, Glu, Asp, or Pro; and (t) L95C is Ser, Trp, Tyr, or Phe; and optionally comprising the following residues: (u) L93 is Ser, Glu, Asp, or His; and (v) L96 is Gly or Asn.E22. The antibody or antigen-binding fragment thereof of any one of embodiments 1-18, comprising the following contact residues (numbering according to Kabat): H33 Ala, H47 Trp, H50 Ala, H51 lie, H52 Ser, H56 Ser, H58 Tyr, H95 Leu, H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu, H100A Ser, L29 Ala, L31 Tyr, L91 Tyr, L95A Ser, L95B Gly, and L95C Ser; and optionally comprising the following residues: L93 Ser and L96 Gly.E23. The antibody or antigen-binding fragment thereof of any one of embodiments 1-22, comprising a heavy chain variable region (VH) that comprises:(a) a VH complementarity determining region one (CDR-H1) comprising the amino acid sequence of SEQ ID NO: 38.(b) a VH complementarity determining region two (CDR-H2) comprising the amino acid sequence of SEQ ID NO: 39; and(c) a VH complementarity determining region three (CDR-H3) comprising the amino acid sequence of SEQ ID NO: 40.E24. The antibody or antigen-binding fragment thereof of any one of embodiments 1-22, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 41.E25. The antibody or antigen-binding fragment thereof of any one of embodiments 1-24, comprising a human VH3 framework sequence. E26. The antibody or antigen-binding fragment thereof of any one of embodiments 1-24, comprising a human VH1 framework sequence.E27. The antibody or antigen-binding fragment thereof of any one of embodiments 1-24, comprising a human VH5 framework sequence.E28. The antibody or antigen-binding fragment thereof of any one of embodiments 1-24, comprising the VH framework sequence of human germline IGHV3-23 or IGHV1-69.E29. The antibody or antigen-binding fragment thereof of any one of embodiments 1-24, comprising the VH framework sequence of human germline IGHV3-7.E30. The antibody or antigen-binding fragment thereof of any one of embodiments 1-24, comprising a human VH germline consensus framework sequence.E31. The antibody or antigen-binding fragment thereof of any one of embodiments 1-30, comprising a VH that comprises an amino acid sequence at least 90% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 41 , 63, and 65.E32. The antibody or antigen-binding fragment thereof of any one of embodiments 1-31 , comprising a VH that comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 41 , 63, and 65.E33. The antibody or antigen-binding fragment thereof of any one of embodiments 1-32, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 41.E34. The antibody or antigen-binding fragment thereof of any one of embodiments 1-32, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 63.E35. The antibody or antigen-binding fragment thereof of any one of embodiments 1-32, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 65.E36. The antibody or antigen-binding fragment thereof of any one of embodiments 1-35, comprising a light chain variable region (VL) that comprises:(a) a VL complementarity determining region one (CDR-L1) comprising the amino acid sequence of SEQ ID NO: 33.(b) a VL complementarity determining region two (CDR-L2) comprising the amino acid sequence of SEQ ID NO: 34; and(c) a VL complementarity determining region three (CDR-L3) comprising the amino acid sequence of SEQ ID NO: 35.E37. The antibody or antigen-binding fragment thereof of any one of embodiments 1-35, comprising the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 36. E38. The antibody or antigen-binding fragment thereof of any one of embodiments 1-37, comprising a human VK framework sequence.E39. The antibody or antigen-binding fragment thereof of any one of embodiments 1-37, comprising a human Vx framework sequence.E40. The antibody or antigen-binding fragment thereof of any one of embodiments 1-37, comprising the VL framework sequence of human germline IGKV3-20.E41. The antibody or antigen-binding fragment thereof of any one of embodiments 1-37, comprising the VL framework sequence of human germline IGKV1-39.E42. The antibody or antigen-binding fragment thereof of any one of embodiments 1-37, comprising a human VL germline consensus framework sequence.E43. The antibody or antigen-binding fragment thereof of any one of embodiments 1-42, comprising a VL that comprises an amino acid sequence at least 90% identical to SEQ ID NO:36.E44. The antibody or antigen-binding fragment thereof of any one of embodiments 1-43, comprising a VL that comprises the amino acid sequence of SEQ ID NO:36.E45. The antibody or antigen-binding fragment thereof of any one of embodiments 1-44, comprising a heavy chain constant region (CH) that comprises an amino acid sequence at least90% identical to SEQ ID NO: 20.E46. The antibody or antigen-binding fragment thereof of any one of embodiments 1-45, comprising a CH that comprises the amino acid sequence of SEQ ID NO: 20.E47. The antibody or antigen-binding fragment thereof of any one of embodiments 1-46, comprising a light chain constant region (CL) that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 26.E48. The antibody or antigen-binding fragment thereof of any one of embodiments 1-47, comprising a CL that comprises the amino acid sequence of SEQ ID NO: 26.E49. The antibody or antigen-binding fragment thereof of any one of embodiments 1-48, comprising an Fc domain.E50. The antibody or antigen-binding fragment thereof of embodiment 49, wherein said Fc domain is the Fc domain of an IgA.E51. The antibody or antigen-binding fragment thereof of embodiment 50, wherein said IgA is IgA, or lgA2.E52. The antibody or antigen-binding fragment thereof of embodiment 49, wherein said Fc domain is the Fc domain of an IgD. E53. The antibody or antigen-binding fragment thereof of embodiment 49, wherein said Fc domain is the Fc domain of an IgE.E54. The antibody or antigen-binding fragment thereof of embodiment 49, wherein said Fc domain is the Fc domain of an IgM.E55. The antibody or antigen-binding fragment thereof of embodiment 49, wherein said Fc domain is the Fc domain of an IgG.E56. The antibody or antigen-binding fragment thereof of embodiment 55, wherein said IgG is Igd , lgG2, lgG3, or lgG4.E57. The antibody or antigen-binding fragment thereof of any one of embodiments 1-56, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 42.E58. The antibody or antigen-binding fragment thereof of any one of embodiments 1-56, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 64.E59. The antibody or antigen-binding fragment thereof of any one of embodiments 1-56, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 66.E60. The antibody or antigen-binding fragment thereof of any one of embodiments 1-59, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 37.E61. The antibody or antigen-binding fragment thereof of any one of embodiments 1-60, comprising the VH sequence encoded by the insert present in the plasmid deposited under ATCCAccession No. PTA-122329.E62. The antibody or antigen-binding fragment thereof of any one of embodiments 1-61 , comprising the VL sequence encoded by the insert present in the plasmid deposited under ATCC Accession No. PTA-122328.E63. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4, wherein said epitope further comprises one or more residues selected from the group consisting of: Glul OO, Glu101 , Asp102, Gly104, and Tyr109, according to the numbering of SEQ ID NO: 2.E64. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63, wherein said epitope further comprises GlulOO, Glu101 , Asp102, Gly104, and Tyr109, according to the numbering of SEQ ID NO: 2.E65. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 64, wherein said epitope does not comprise one or more residues selected from the group consisting of: P103, T1 1 1 , Y1 13, F1 14, N116, Q1 18, Q121 , C122, E123, R124, F125, K126, and L140 (numbering according to SEQ ID NO: 2). E66. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 65, wherein said epitope does not comprise: P103, T1 1 1 , Y1 13, F1 14, N116, Q1 18, Q121 , C122, E123, R124, F125, K126, and L140 (numbering according to SEQ ID NO: 2).E67. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 64, wherein said epitope does not comprise one or more residues selected from the group consisting of: D31 , D32, P34, C35, K36, P103, K126, Y127, G128 (numbering according to SEQ ID NO: 2).E68. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4, 63-64, and 67, wherein said epitope does not comprise: D31 , D32, P34, C35, K36, P103, K126, Y127, G128 (numbering according to SEQ ID NO: 2).E69. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-68, comprising the following residues (numbering according to Kabat): H33 Ala, H35 Gin, H52 Ser, H53 Asn, H55 Arg, H56 Ser, H95 Phe, H96 Leu, H97 His, H99 Ser, H101 Asp, L31 Met, L32 Tyr, L34 His, L36 Tyr, L50 Arg, L91 Trp, and L96 Tyr.E70. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-69, comprising a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 48.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 49; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 50.E71. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-69, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 51.E72. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-71 , comprising a human VH3, VH1 , or VH5 framework sequence.E73. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-72, comprising the VH framework sequence of human germline IGHV3-23 or IGHV1-69.E74. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 72, comprising the VH framework sequence of human germline IGHV3-7.E75. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 71 , comprising a human VH germline consensus framework sequence.E76. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 75, comprising a VH that comprises an amino acid sequence at least 90% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 67, 69, 51 , and 79. E77. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-76, comprising a VH that comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 67, 69, 51 , and 79.E78. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-77, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 67.E79. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-77, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 69.E80. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-77, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 51 .E81. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-77, comprising a heavy chain variable region (VH) that comprises the amino acid sequence of SEQID NO: 79.E82. The antibody or antigen-binding fragment thereof according to any one of embodiments 1-4 and 63-81 , comprising a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 43.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 44; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 45.E83. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-81 , comprising the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 46.E84. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-83, comprising a human VK or νλ framework sequence.E85. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-84, comprising the VL framework sequence of human germline IGKV3-20 or IGKV1-39.E86. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 83, comprising a human VL germline consensus framework sequence.E87. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-86, comprising a VL that comprises an amino acid sequence at least 90% identical to a sequence selected from the group consisting of SEQ ID NOs: 46, 71 , 73, 75, and 77.E88. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-87, comprising a VL that comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 46, 71 , 73, 75, and 77.E89. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-88, comprising a VL that comprises the amino acid sequence of SEQ ID NO:46. E90. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-88, comprising a VL that comprises the amino acid sequence of SEQ ID NO:71.E91. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-88, comprising a VL that comprises the amino acid sequence of SEQ ID NO:73.E92. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-88, comprising a VL that comprises the amino acid sequence of SEQ ID NO:75.E93. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-88, comprising a VL that comprises the amino acid sequence of SEQ ID NO:77.E94. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-93, comprising a CH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 20.E95. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-94, comprising a CH that comprises the amino acid sequence of SEQ ID NO: 20.E96. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-95, comprising a CL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 26.E97. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-96, comprising a CL that comprises the amino acid sequence of SEQ ID NO: 26.E98. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63-97, comprising an Fc domain.E99. The antibody or antigen-binding fragment thereof of embodiment 98, wherein said Fc domain is the Fc domain of an IgA.E100. The antibody or antigen-binding fragment thereof of embodiment 99, wherein said IgA is IgA, or lgA2.E101. The antibody or antigen-binding fragment thereof of embodiment 98, wherein said Fc domain is the Fc domain of an IgD, IgE, or IgM.E102. The antibody or antigen-binding fragment thereof of embodiment 98, wherein said Fc domain is the Fc domain of an IgG.E103. The antibody or antigen-binding fragment thereof of embodiment 102, wherein said IgG is IgGi , lgG2, lgG3, or lgG4.E104. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 103, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 52. E105. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 103, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 68.E106. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 103, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 70.E107. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 103, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 80.E108. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 107, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 47.E109. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 107, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 72.E1 10. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 107, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 74.E1 11 . The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 107, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 76.E1 12. The antibody or antigen-binding fragment thereof of any one of embodiments 1-4 and 63- 107, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 78.E1 13. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to an epitope in Kunitz Domain 2 (K2) of Tissue Factor Pathway Inhibitor (TFPI), wherein said epitope comprises residues Glu101 , Pro103, Tyr109, Thr1 11 , Ser1 19, Gln121 , Glu123, Arg124, Lys126, and Leu140, according to the numbering of SEQ ID NO: 2.E1 14. The antibody or antigen-binding fragment thereof of embodiment 113, wherein said antibody, or antigen-binding fragment thereof, does not bind to Kunitz Domain 1 (K1) of TFPI. E115. The antibody or antigen-binding fragment thereof of embodiment 113 or 1 14, wherein said epitope does not comprise one or more residues selected from the group consisting of: E100, D102, R107, Y1 13, F1 14, N1 16, Q1 18, and C122 (numbering according to SEQ ID NO: 2).E116. The antibody or antigen-binding fragment thereof of any one of embodiments 113-1 15, wherein said epitope does not comprise: E100, D102, R107, Y1 13, F1 14, N1 16, Q1 18, and C122 (numbering according to SEQ ID NO: 2).E117. The antibody or antigen-binding fragment thereof of embodiment 1 13 or 1 14, wherein said epitope does not comprise one or more residues selected from the group consisting of: D31 , D32, P34, C35, K36, E100, 1105, R107, G108, Y127, and G128 (numbering according to SEQ ID NO: 2). E118. The antibody or antigen-binding fragment thereof of any one of embodiments 113-1 14 and 117, wherein said epitope does not comprise: D31 , D32, P34, C35, K36, E100, 1105, R107, G108, Y127, and G128 (numbering according to SEQ ID NO: 2).E119. The antibody or antigen-binding fragment thereof of embodiment 113-1 18, comprising the following residues (according to Kabat numbering): H50 Asp, H57 Thr, H58 Leu, H59 Tyr, H61 Gin, H98 Asp, H99 Tyr, H100 Asp, L30 His, L50 Trp, L92 Tyr, L93 Thr, L94 Thr, and L96 Tyr.E120. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-1 19, comprising a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 87.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 88; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 89.E121. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-1 19, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 90.E122. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-121 , comprising a human VH3, VH1 , or VH5 framework sequence.E123. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-122, comprising the VH framework sequence of human germline IGHV3-23, IGHV1-69, or IGHV3-7.E124. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-121 , comprising a human VH germline consensus framework sequence.E125. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-124, comprising a VH that comprises an amino acid sequence at least 90% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 90, 95, 97, 99, 101 , 103, 105, and 107.E126. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-125, comprising a VH that comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 90, 95, 97, 99, 101 , 103, 105, and 107.E127. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-126, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 90.E128. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-126, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 95.E129. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-126, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 97. E130. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-126, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 99.E131 . The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-126, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 101.E132. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-126, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 103.E133. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-126, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 105.E134. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-126, comprising a VH that comprises the amino acid sequence of SEQ ID NO: 107.E135. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-134, comprising a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 81.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 82; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 83.E136. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-134, comprising the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 84.E137. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-136, comprising a human VK or νλ framework sequence.E138. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-137, comprising the VL framework sequence of human germline IGKV3-20 or IGKV1-39.E139. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-136, comprising a human VL germline consensus framework sequence.E140. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-139, comprising a VL that comprises an amino acid sequence at least 90% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 84, 109, and 1 1 1.E141 . The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-140, comprising a VL that comprises an amino acid sequence selected from the group consisting of SEQ ID NOs: 84, 109, and 1 1 1.E142. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-141 , comprising a VL that comprises the amino acid sequence of SEQ ID NO:84.E143. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-141 , comprising a VL that comprises the amino acid sequence of SEQ ID NO: 109. E144. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-141 , comprising a VL that comprises the amino acid sequence of SEQ ID NO:11 1 .E145. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-144, comprising a CH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 20.E146. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-145, comprising a CH that comprises the amino acid sequence of SEQ ID NO: 20.E147. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-144, comprising a CH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 91.E148. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-144 and147, comprising a CH that comprises the amino acid sequence of SEQ ID NO: 91.E149. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-148, comprising a CL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 14.E150. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-149, comprising a CL that comprises the amino acid sequence of SEQ ID NO: 14.E151 . The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-148, comprising a CL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 85.E152. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-148 and151 , comprising a CL that comprises the amino acid sequence of SEQ ID NO: 85.E153. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-152, comprising an Fc domain.E154. The antibody or antigen-binding fragment thereof of embodiment 153, wherein said Fc domain is the Fc domain of an IgA (e.g., IgAi or lgA2).E155. The antibody or antigen-binding fragment thereof of embodiment 153, wherein said Fc domain is the Fc domain of an IgD, IgE, or IgM.E156. The antibody or antigen-binding fragment thereof of embodiment 153, wherein said Fc domain is the Fc domain of an IgG.E157. The antibody or antigen-binding fragment thereof of embodiment 156, wherein said IgG is IgG, , lgG2, lgG3, or lgG4.E158. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 92.E159. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 94. E160. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 96.E161 . The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 98.E162. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 100.E163. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 102.E164. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 104.E165. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 106.E166. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-157, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 108.E167. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-166, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 86.E168. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-166, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 93.E169. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-166, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 1 10.E170. The antibody or antigen-binding fragment thereof of any one of embodiments 1 13-166, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 1 12.E171. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to theKunitz Domain 2 (K2) of TFPI, comprising a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 16.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 17; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 18.E172. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 19.E173. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 10.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 11 ; and (c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 12.E174. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 13. E175. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising:(i) a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 16.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 17; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 18;and (ii) a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 10.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 1 1 ; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 12.E176. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 19, and the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 13.E177. The antibody or antigen-binding fragment thereof of any one of embodiments 171-176, comprising a human VH3, VH1 , or VH5 framework sequence.E178. The antibody or antigen-binding fragment thereof of any one of embodiments 171-177, comprising the VH framework sequence of human germline IGHV3-23, IGHV1-69, or IGHV3-7.E179. The antibody or antigen-binding fragment thereof of any one of embodiments 171-176, comprising a human VH germline consensus framework sequence.E180. The antibody or antigen-binding fragment thereof of any one of embodiments 171-179, comprising a VH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 19. E181 . The antibody or antigen-binding fragment thereof of any one of embodiments 171 -180, comprising a VH that comprises the amino acid sequence of SEQ ID NO. 19.E182. The antibody or antigen-binding fragment thereof of any one of embodiments 171-181 , comprising a human VK or V¾. framework sequence.E183. The antibody or antigen-binding fragment thereof of any one of embodiments 171-182, comprising the VL framework sequence of human germline IGKV3-20 or IGKV1-39.E184. The antibody or antigen-binding fragment thereof of any one of embodiments 171-181 , comprising a human VL germline consensus framework sequence. E185. The antibody or antigen-binding fragment thereof of any one of embodiments 171 -184, comprising a VL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 13.E186. The antibody or antigen-binding fragment thereof of any one of embodiments 171 -185, comprising a VL that comprises the amino acid sequence of SEQ I D NO: 13.E187. The antibody or antigen-binding fragment thereof of any one of embodiments 171 -186, comprising a CH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 20.E188. The antibody or antigen-binding fragment thereof of any one of embodiments 171 -187, comprising a CH that comprises the amino acid sequence of SEQ ID NO: 20.E189. The antibody or antigen-binding fragment thereof of any one of embodiments 171 -188, comprising a CL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 14.E190. The antibody or antigen-binding fragment thereof of any one of embodiments 171 -189, comprising a CL that comprises the amino acid sequence of SEQ ID NO: 14.E191 . The antibody or antigen-binding fragment thereof of any one of embodiments 171 -190, comprising an Fc domain.E192. The antibody or antigen-binding fragment thereof of embodiment 191 , wherein said Fc domain is the Fc domain of an IgA (e.g. , \gA-\ or lgA2), IgD, IgE, or IgM.E193. The antibody or antigen-binding fragment thereof of embodiment 191 , wherein said Fc domain is the Fc domain of an IgG.E194. The antibody or antigen-binding fragment thereof of embodiment 193, wherein said IgG is IgG, , lgG2, lgG3, or lgG4.E195. The antibody or antigen-binding fragment thereof of any one of embodiments 171 -194, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 21 .E196. The antibody or antigen-binding fragment thereof of any one of embodiments 171 -195, comprising a light chain that comprises the amino acid sequence of SEQ I D NO: 15.E197. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ I D NO: 28.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 29; and(c) a CDR-H3 comprising the amino acid sequence of SEQ I D NO: 30.E198. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 31 .E199. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising a VL that comprises: (a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 22.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 23; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 24.E200. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 25. E201 . An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising:(i) a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 28.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 29; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 30;and (ii) a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 22.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 23; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 24.E202. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 31 , and the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 25.E203. The antibody or antigen-binding fragment thereof of any one of embodiments 197-202, comprising a human VH3, VH1 , or VH5 framework sequence.E204. The antibody or antigen-binding fragment thereof of any one of embodiments 197-203, comprising the VH framework sequence of human germline IGHV3-23, IGHV1-69, or IGHV3-7.E205. The antibody or antigen-binding fragment thereof of any one of embodiments 197-202, comprising a human VH germline consensus framework sequence.E206. The antibody or antigen-binding fragment thereof of any one of embodiments 197-205, comprising a VH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 31. E207. The antibody or antigen-binding fragment thereof of any one of embodiments 197-206, comprising a VH that comprises the amino acid sequence of SEQ ID NO. 31.E208. The antibody or antigen-binding fragment thereof of any one of embodiments 197-207, comprising a human VK or V¾. framework sequence. E209. The antibody or antigen-binding fragment thereof of any one of embodiments 197-208, comprising the VL framework sequence of human germline IGKV3-20 or IGKV1 -39.E210. The antibody or antigen-binding fragment thereof of any one of embodiments 197-207, comprising a human VL germline consensus framework sequence.E21 1 . The antibody or antigen-binding fragment thereof of any one of embodiments 197-210, comprising a VL that comprises an amino acid sequence at least 90% identical to SEQ I D NO: 25.E212. The antibody or antigen-binding fragment thereof of any one of embodiments 197-21 1 , comprising a VL that comprises the amino acid sequence of SEQ I D NO: 25.E213. The antibody or antigen-binding fragment thereof of any one of embodiments 197-212, comprising a CH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 20.E214. The antibody or antigen-binding fragment thereof of any one of embodiments 197-213, comprising a CH that comprises the amino acid sequence of SEQ ID NO: 20.E215. The antibody or antigen-binding fragment thereof of any one of embodiments 197-214, comprising a CL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 26.E216. The antibody or antigen-binding fragment thereof of any one of embodiments 197-215, comprising a CL that comprises the amino acid sequence of SEQ I D NO: 26.E217. The antibody or antigen-binding fragment thereof of any one of embodiments 197-216, comprising an Fc domain.E218. The antibody or antigen-binding fragment thereof of embodiment 217, wherein said Fc domain is the Fc domain of an IgA (e.g. , \gA-\ or lgA2), IgD, IgE, or IgM.E219. The antibody or antigen-binding fragment thereof of embodiment 217, wherein said Fc domain is the Fc domain of an IgG (e.g. , IgG^ lgG2, lgG3, or lgG4).E220. The antibody or antigen-binding fragment thereof of any one of embodiments 197-219, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 32.E221 . The antibody or antigen-binding fragment thereof of any one of embodiments 197-220, comprising a light chain that comprises the amino acid sequence of SEQ I D NO: 27.E222. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI , comprising a heavy chain variable region (VH) that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ I D NO: 58.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 59; and(c) a CDR-H3 comprising the amino acid sequence of SEQ I D NO: 60.E223. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 61 . E224. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 53.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 54; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 55.E225. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 56. E226. An isolated antibody, or antigen-binding fragment thereof, that specifically binds the K2 Domain of TFPI, comprising:(i) a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 58.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 59; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 60;and (ii) a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 53.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 54; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 55.E227. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 61 , and the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 56.E228. The antibody or antigen-binding fragment thereof of any one of embodiments 222-227, comprising a human VH3, VH1 , or VH5 framework sequence.E229. The antibody or antigen-binding fragment thereof of any one of embodiments 222-228, comprising the VH framework sequence of human germline IGHV3-23, IGHV1-69, or IGHV3-7.E230. The antibody or antigen-binding fragment thereof of any one of embodiments 222-227, comprising a human VH germline consensus framework sequence.E231 . The antibody or antigen-binding fragment thereof of any one of embodiments 222-230, comprising a VH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 61. E232. The antibody or antigen-binding fragment thereof of any one of embodiments 222-231 , comprising a VH that comprises the amino acid sequence of SEQ ID NO. 61. E233. The antibody or antigen-binding fragment thereof of any one of embodiments 222-232, comprising a human VK or V¾. framework sequence.E234. The antibody or antigen-binding fragment thereof of any one of embodiments 222-233, comprising the VL framework sequence of human germline IGKV3-20 or IGKV1-39.E235. The antibody or antigen-binding fragment thereof of any one of embodiments 222-232, comprising a human VL germline consensus framework sequence.E236. The antibody or antigen-binding fragment thereof of any one of embodiments 222-235, comprising a VL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 56.E237. The antibody or antigen-binding fragment thereof of any one of embodiments 222-236, comprising a VL that comprises the amino acid sequence of SEQ ID NO: 56.E238. The antibody or antigen-binding fragment thereof of any one of embodiments 222-237, comprising a CH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 20.E239. The antibody or antigen-binding fragment thereof of any one of embodiments 222-238, comprising a CH that comprises the amino acid sequence of SEQ ID NO: 20.E240. The antibody or antigen-binding fragment thereof of any one of embodiments 222-239, comprising a CL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 26.E241 . The antibody or antigen-binding fragment thereof of any one of embodiments 222-240, comprising a CL that comprises the amino acid sequence of SEQ ID NO: 26.E242. The antibody or antigen-binding fragment thereof of any one of embodiments 222-241 , comprising an Fc domain.E243. The antibody or antigen-binding fragment thereof of embodiment 242, wherein said Fc domain is the Fc domain of an IgA (e.g., IgAi or lgA2), IgD, IgE, or IgM.E244. The antibody or antigen-binding fragment thereof of embodiment 242, wherein said Fc domain is the Fc domain of an IgG (e.g., IgGi, lgG2, lgG3, or lgG4).E245. The antibody or antigen-binding fragment thereof of any one of embodiments 222-244, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 62.E246. The antibody or antigen-binding fragment thereof of any one of embodiments 222-245, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 57.E247. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 1 18.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 1 19; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 120. E248. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 121.E249. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 1 13.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 1 14; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 1 15.E250. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 116. E251 . An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising:(i) a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 1 18.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 1 19; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 120;and (ii) a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 1 13.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 1 14; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 115.E252. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 121 , and the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 116.E253. The antibody or antigen-binding fragment thereof of any one of embodiments 247-252, comprising a human VH3, VH1 , or VH5 framework sequence.E254. The antibody or antigen-binding fragment thereof of any one of embodiments 247-253, comprising the VH framework sequence of human germline IGHV3-23, IGHV1-69, or IGHV3-7.E255. The antibody or antigen-binding fragment thereof of any one of embodiments 247-252, comprising a human VH germline consensus framework sequence.E256. The antibody or antigen-binding fragment thereof of any one of embodiments 247-255, comprising a VH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 121. E257. The antibody or antigen-binding fragment thereof of any one of embodiments 247-256, comprising a VH that comprises the amino acid sequence of SEQ ID NO. 121.E258. The antibody or antigen-binding fragment thereof of any one of embodiments 247-257, comprising a human V or νλ framework sequence.E259. The antibody or antigen-binding fragment thereof of any one of embodiments 247-258, comprising the VL framework sequence of human germline IGKV3-20 or IGKV1-39.E260. The antibody or antigen-binding fragment thereof of any one of embodiments 247-257, comprising a human VL germline consensus framework sequence.E261 . The antibody or antigen-binding fragment thereof of any one of embodiments 247-260, comprising a VL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 1 16.E262. The antibody or antigen-binding fragment thereof of any one of embodiments 247-261 , comprising a VL that comprises the amino acid sequence of SEQ ID NO: 1 16.E263. The antibody or antigen-binding fragment thereof of any one of embodiments 247-262, comprising a CH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 91.E264. The antibody or antigen-binding fragment thereof of any one of embodiments 247-263, comprising a CH that comprises the amino acid sequence of SEQ ID NO: 91.E265. The antibody or antigen-binding fragment thereof of any one of embodiments 247-264, comprising a CL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 85.E266. The antibody or antigen-binding fragment thereof of any one of embodiments 247-265, comprising a CL that comprises the amino acid sequence of SEQ ID NO: 85.E267. The antibody or antigen-binding fragment thereof of any one of embodiments 247-266, comprising an Fc domain.E268. The antibody or antigen-binding fragment thereof of embodiment 267, wherein said Fc domain is the Fc domain of an IgA (e.g., IgAi or lgA2), IgD, IgE, or IgM.E269. The antibody or antigen-binding fragment thereof of embodiment 267, wherein said Fc domain is the Fc domain of an IgG (e.g., IgG^ lgG2, lgG3, or lgG4).E270. The antibody or antigen-binding fragment thereof of any one of embodiments 247-269, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 122.E271 . The antibody or antigen-binding fragment thereof of any one of embodiments 247-270, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 117.E272. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 128. (b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 129; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 130.E273. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 131.E274. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 123.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 124; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 125.E275. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 126. E276. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising:(i) a VH that comprises:(a) a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 128.(b) a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 129; and(c) a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 130;and (ii) a VL that comprises:(a) a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 123.(b) a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 124; and(c) a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 125.E277. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to the PC- Domain of TFPI, comprising the CDR-H1 , CDR-H2, and CDR-H3 sequences of SEQ ID NO: 131 , and the CDR-L1 , CDR-L2, and CDR-L3 sequences of SEQ ID NO: 126.E278. The antibody or antigen-binding fragment thereof of any one of embodiments 272-277, comprising a human VH3, VH1 , or VH5 framework sequence.E279. The antibody or antigen-binding fragment thereof of any one of embodiments 272-278, comprising the VH framework sequence of human germline IGHV3-23, IGHV1 -69, or IGHV3-7.E280. The antibody or antigen-binding fragment thereof of any one of embodiments 272-277, comprising a human VH germline consensus framework sequence. E281 . The antibody or antigen-binding fragment thereof of any one of embodiments 272-280, comprising a VH that comprises an amino acid sequence at least 90% identical to SEQ I D NO: 131 .E282. The antibody or antigen-binding fragment thereof of any one of embodiments 272-281 , comprising a VH that comprises the amino acid sequence of SEQ I D NO. 131 .E283. The antibody or antigen-binding fragment thereof of any one of embodiments 272-282, comprising a human VK or V¾. framework sequence.E284. The antibody or antigen-binding fragment thereof of any one of embodiments 272-283, comprising the VL framework sequence of human germline IGKV3-20 or IGKV1 -39.E285. The antibody or antigen-binding fragment thereof of any one of embodiments 272-282, comprising a human VL germline consensus framework sequence.E286. The antibody or antigen-binding fragment thereof of any one of embodiments 272-285, comprising a VL that comprises an amino acid sequence at least 90% identical to SEQ I D NO: 126.E287. The antibody or antigen-binding fragment thereof of any one of embodiments 272-286, comprising a VL that comprises the amino acid sequence of SEQ I D NO: 126.E288. The antibody or antigen-binding fragment thereof of any one of embodiments 272-287, comprising a CH that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 91 .E289. The antibody or antigen-binding fragment thereof of any one of embodiments 272-288, comprising a CH that comprises amino acid sequence of SEQ ID NO: 91 .E290. The antibody or antigen-binding fragment thereof of any one of embodiments 272-289, comprising a CL that comprises an amino acid sequence at least 90% identical to SEQ ID NO: 85.E291 . The antibody or antigen-binding fragment thereof of any one of embodiments 272-290, comprising a CL that comprises the amino acid sequence of SEQ ID NO: 85.E292. The antibody or antigen-binding fragment thereof of any one of embodiments 272-291 , comprising an Fc domain.E293. The antibody or antigen-binding fragment thereof of embodiment 292, wherein said Fc domain is the Fc domain of an IgA (e.g. , \gA^ or lgA2), IgD, IgE, or IgM.E294. The antibody or antigen-binding fragment thereof of embodiment 292, wherein said Fc domain is the Fc domain of an IgG (e.g. , IgG^ lgG2, lgG3, or lgG4).E295. The antibody or antigen-binding fragment thereof of any one of embodiments 272-294, comprising a heavy chain that comprises the amino acid sequence of SEQ ID NO: 132.E296. The antibody or antigen-binding fragment thereof of any one of embodiments 272-295, comprising a light chain that comprises the amino acid sequence of SEQ ID NO: 127. E297. An antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI, wherein said antibody or antigen-binding fragment thereof competes for binding to TFPI with the antibody or antigen-binding fragment thereof of any one of embodiments 1-296.E298. An antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI, wherein said antibody or antigen-binding fragment thereof competes for binding to TFPI with an antibody selected from the group consisting of: TFPI-3, TFPI-21 , TFPI-23, TFPI-24, TFPI-26, TFPI-106, TFPI-107, TFPI-108, TFPI-109, TFPI-1 10, TFPI-1 1 1 , TFPI-1 12, TFPI-1 13, TFPI-1 14, TFPI-1 15, TFPI-1 18, TFPI-1 19, TFPI-122, TFPI-123, TFPI-126, 4D8.b1 , mu-hu 4D8 chimera, 4D8- VklO x VH1.0, 4D8-Vk1.0 x VH1.1 , 4D8-Vk1.0 x VH1.2, 4D8-Vk1.0 x VH1.3, 4D8-Vk1.0 x VH1.4, 4D8-Vk1.0 x VH1.5, 4D8-Vk1.0 x VH1.6, 4D8-Vk1.1 x VH1.0, 4D8-Vk1.1 x VH1.1 , 4D8-Vk1.1 x VH1.2, 4D8-Vk1.1 x VH1.3, 4D8-Vk1.1 x VH1.4, 4D8-Vk1.1 x VH1.5, 4D8-Vk1.1 x VH1.6, hz4D8, 6B7.C5, and 7A4.D9.E299. An antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI, wherein said antibody or antigen-binding fragment thereof competes for binding to TFPI with an antibody selected from the group consisting of: TFPI-23, TFPI-24, TFPI-106, and TFPI-1 18. E300. The antibody or antigen-binding fragment thereof of embodiment 299, wherein said antibody or antigen-binding fragment thereof competes for binding to TFPI with TFPI-23 or TFPI- 106.E301. The antibody or antigen-binding fragment thereof of embodiment 299, wherein said antibody or antigen-binding fragment thereof competes for binding to TFPI with TFPI-24 or TFPI- 118.E302. An antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI, wherein said antibody or antigen-binding fragment thereof competes for binding to TFPI with antibody 4D8.E303. An antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI, wherein said antibody or antigen-binding fragment thereof binds to the same TFPI epitope as the antibody or antigen-binding fragment thereof of any one of embodiments 1-296.E304. An antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI, wherein said antibody or antigen-binding fragment thereof binds to the same TFPI epitope as an antibody selected from the group consisting of: TFPI-3, TFPI-21 , TFPI-23, TFPI-24, TFPI-26, TFPI-106, TFPI-107, TFPI-108, TFPI-109, TFPI-1 10, TFPI-1 1 1 , TFPI-1 12, TFPI-1 13, TFPI-1 14, TFPI-1 15, TFPI-1 18, TFPI-1 19, TFPI-122, TFPI-123, TFPI-126, 4D8.b1 , mu-hu 4D8 chimera, 4D8- VklO x VH1.0, 4D8-Vk1.0 x VH1.1 , 4D8-Vk1.0 x VH1.2, 4D8-Vk1.0 x VH1.3, 4D8-Vk1.0 x VH1.4, 4D8-Vk1.0 x VH1.5, 4D8-Vk1.0 x VH1.6, 4D8-Vk1.1 x VH1.0, 4D8-Vk1.1 x VH1.1 , 4D8-Vk1.1 x VH1.2, 4D8-Vk1.1 x VH1.3, 4D8-Vk1.1 x VH1.4, 4D8-Vk1.1 x VH1.5, 4D8-Vk1.1 x VH1.6, hz4D8, 6B7.C5, and 7A4.D9.E305. An antibody, or antigen-binding fragment thereof, that specifically binds the K2 Domain of TFPI, wherein said antibody or antigen-binding fragment thereof binds to the same TFPI epitope as an antibody selected from the group consisting of: TFPI-23, TFPI-24, TFPI-106, and TFPI-1 18. E306. The antibody or antigen-binding fragment thereof of embodiment 305, wherein said antibody or antigen-binding fragment thereof binds to the same TFPI epitope as TFPI-23 or TFPI- 106.E307. The antibody or antigen-binding fragment thereof of embodiment 305, wherein said antibody or antigen-binding fragment thereof binds to the same TFPI epitope as TFPI-24 or TFPI- 118.E308. An antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI, wherein said antibody or antigen-binding fragment thereof binds to the same TFPI epitope as antibody 4D8.E309. The antibody or antigen-binding fragment thereof of any one of embodiments 297-308, wherein said antibody or antigen-binding fragment thereof does not bind to the K1 Domain of TFPI. E310. The antibody or antigen-binding fragment thereof of any one of embodiments 1-309, wherein the antibody or antigen-binding fragment is an Fc fusion protein, a monobody, a maxibody, a bifunctional antibody, an scFab, an scFv, a peptibody, or an antigen-binding fragment of any of the foregoing.E311. The antibody or antigen-binding fragment thereof of any one of embodiments 1-310, wherein said antibody or antigen-binding fragment binds to TFPI with a binding affinity (Kd) value from about 1x10"7 M to about 1x10"12 M.E312. The antibody or antigen-binding fragment thereof of any one of embodiments 1-311 , wherein said antibody or antigen-binding fragment binds to TFPI with a binding affinity (Kd) value from about 5x10"7 M to about 5x10"11 M.E313. The antibody or antigen-binding fragment thereof of any one of embodiments 1-312, wherein said antibody or antigen-binding fragment binds to TFPI with a binding affinity (Kd) value of from about 1x10"8 M to about 1x10"10 M.E314. The antibody or antigen-binding fragment thereof of any one of embodiments 1-313, wherein said antibody or antigen-binding fragment: (i) decreases clotting time as measured in a plasma based dilute prothrombin time (dPT) assay; (ii) reduces clotting time in whole blood as measured by thromboelastrography or rotational thromboelastometry; (iii) increases thrombin generation; (iv) increases FXa activity in the presence of TFPI; or (v) any combination thereof. E315. The antibody or antigen-binding fragment thereof of embodiment 314, wherein said antibody or antigen-binding fragment decreases clotting time as measured in a plasma based dilute prothrombin time assay.E316. The antibody or antigen-binding fragment thereof of embodiment 315, wherein said decrease in clotting time, as measured in a plasma based dilute prothrombin time assay, is dose- dependent.E317. The antibody or antigen-binding fragment thereof of embodiment 314, wherein said antibody or antigen-binding fragment reduces clotting time in whole blood as measured by thromboelastrography or rotational thromboelastometry.E318. The antibody or antigen-binding fragment thereof of embodiment 317, wherein said reduction in clotting time, as measured by thromboelastrography or rotational thromboelastometry, is dose-dependent.E319. The antibody or antigen-binding fragment thereof of embodiment 314, wherein said antibody or antigen-binding fragment increases thrombin generation.E320. The antibody or antigen-binding fragment thereof of embodiment 319, wherein said increase in thrombin generation, is dose-dependent.E321. The antibody or antigen-binding fragment thereof of embodiment 314, wherein said antibody or antigen-binding fragment increases FXa activity in the presence of TFPI.E322. The antibody or antigen-binding fragment thereof of embodiment 321 , wherein said increase in FXa activity in the presence of TFPI, is dose-dependent.E323. The antibody or antigen-binding fragment thereof of embodiment 322, wherein said antibody enhances platelet accumulation in the presence of TFPI.E324. The antibody or antigen-binding fragment thereof of embodiment 323, wherein said enhancement of platelet accumulation in the presence of TFPI is dose-dependent.E325. The antibody or antigen-binding fragment thereof of embodiment 324, wherein said antibody increases fibrin generation in the presence of TFPI.E326. The antibody or antigen-binding fragment thereof of embodiment 325, wherein said increase in fibrin generation in the presence of TFPI is dose-dependent. E327. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time in whole blood is determined using whole blood obtained from a human patient having severe hemophilia A.E328. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time in whole blood is determined using whole blood obtained from a human patient having severe hemophilia A and inhibitory antibodies against human Factor VIII.E329. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time in whole blood is determined using whole blood obtained from a human patient having moderate hemophilia A.E330. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time in whole blood is determined using whole blood obtained from a human patient having severe hemophilia B.E331 . The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time in whole blood is determined using whole blood obtained from a human patient having severe hemophilia B and inhibitory antibodies against human Factor IX.E332. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time in whole blood is determined using whole blood obtained from a human patient having moderate hemophilia B.E333. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time as measured in a dPT assay is determined using plasma obtained from a human patient having severe hemophilia A.E334. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time as measured in a dPT assay is determined using plasma obtained from a human patient having severe hemophilia A and inhibitory antibodies against human Factor VIII.E335. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time as measured in a dPT assay is determined using plasma obtained from a human patient having moderate hemophilia A.E336. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time as measured in a dPT assay is determined using plasma obtained from a human patient having severe hemophilia B.E337. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time as measured in a dPT assay is determined using plasma obtained from a human patient having severe hemophilia B and inhibitory antibodies against human Factor IX. E338. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the reduction in clotting time as measured in a dPT assay is determined using plasma obtained from a human patient having moderate hemophilia B.E339. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the increase in thrombin generation is determined using plasma obtained from a human patient having severe hemophilia A.E340. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the increase in thrombin generation is determined using plasma obtained from a human patient having severe hemophilia A and inhibitory antibodies against human Factor VIII.E341. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the increase in thrombin generation is determined using plasma obtained from a human patient having moderate hemophilia A.E342. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the increase in thrombin generation is determined using plasma obtained from a human patient having severe hemophilia B.E343. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the increase in thrombin generation is determined using plasma obtained from a human patient having severe hemophilia B and inhibitory antibodies against human Factor IX.E344. The antibody or antigen-binding fragment thereof of embodiment 314, wherein the increase in thrombin generation is determined using plasma obtained from a human patient having moderate hemophilia B.E345. The antibody or antigen-binding fragment thereof of embodiment 314, wherein 100 nM of said antibody or antigen-binding fragment thereof is at least as effective in reducing clotting time of whole blood obtained from a human patient having severe hemophilia A as an amount of recombinant human Factor VIII that is sufficient to achieve 5% of normal clotting activity.E346. The antibody or antigen-binding fragment thereof of embodiment 314, wherein 100 nM of said antibody or antigen-binding fragment thereof is at least as effective in increasing peak thrombin generation in platelet rich plasma obtained from a human patient having severe hemophilia A as an amount of recombinant human Factor VIII that is sufficient to achieve 5% of normal clotting activity.E347. The antibody or antigen-binding fragment thereof of any one of embodiments 1-346, wherein said TFPI is human TFPI. E348. The antibody or antigen-binding fragment thereof of any one of embodiments 1-347, wherein said TFPI comprises residues 91-147 SEQ ID NO: 2.E349. An isolated nucleic acid molecule or nucleic acid molecules, comprising one or more nucleotide sequences encoding the antibody or antigen-binding fragment thereof of any one of embodiments 1-348.E350. An isolated nucleic acid molecule encoding an antibody, or antigen-binding fragment thereof, that specifically binds TFPI, wherein said nucleic acid comprises a nucleic acid sequence selected from the group consisting of: the nucleic acid sequence of SEQ ID NO: 175, the nucleic acid sequence of SEQ ID NO: 176, the nucleic acid sequence of SEQ ID NO:177, the nucleic acid sequence of SEQ ID NO:178, the nucleic acid sequence of the insert of the vector deposited as mAb-TFPI-106 VL under ATCC Accession Number PTA-122328, and the nucleic acid sequence of the insert of the vector deposited as mAb-TFPI-106 VH under ATCC Accession Number PTA- 122329.E351 . A vector comprising the nucleic acid molecule of embodiments 349 and 350.E352. A host cell comprising the nucleic acid molecule of embodiment 349 or 350, or the vector of embodiment 351.E353. The host cell of embodiment 352, wherein said cell is a mammalian cell.E354. The host cell of embodiment 353, wherein said host cell is a CHO cell, a HEK-293 cell, or an Sp2.0 cell.E355. A method of making an antibody or antigen-binding fragment thereof, comprising culturing the host cell of any one of embodiments 352-354, under a condition wherein said antibody or antigen-binding fragment is expressed by said host cell.E356. The method of embodiment 355, further comprising isolating said antibody or antigen- binding fragment thereof.E357. An antibody or antigen-binding fragment thereof obtained by the method of embodiment 355 or 356.E358. A pharmaceutical composition comprising an antibody or antigen-binding fragment thereof of any one of embodiments 1-347 and 357, and a pharmaceutically acceptable carrier or excipient. E359. A method of reducing the activity of Tissue Factor Pathway Inhibitor (TFPI), comprising administering to a subject in need thereof a therapeutically effective amount of the antibody or antigen-binding fragment thereof of any one of embodiments 1-347 and 357, or the pharmaceutical composition of embodiment 358. E360. A method of shortening bleeding time, comprising administering to a subject in need thereof a therapeutically effective amount of the antibody or antigen-binding fragment thereof of any one of embodiments 1-347 and 357, or the pharmaceutical composition of embodiment 358.E361 . The method of embodiment 358 or 360, wherein said subject is a human.E362. The method of any one of embodiments 359-361 , wherein said subject suffers from or is susceptible to a deficiency in blood coagulation.E363. The method of any one of embodiments 359-361 , wherein said subject suffers from or is susceptible to a platelet disorder.E364. The method of any one of embodiments 359-361 , wherein said subject suffers from or is susceptible to hemophilia A, B or C.E365. The method of any one of embodiments 359-361 , wherein said subject suffers from or is susceptible to hemophilia A or B.E366. The method of any one of embodiments 359-361 , wherein said subject suffers from or is susceptible to von Willebrand Disease (vWD).E367. The method of embodiment 360, further comprising administering a therapeutically effective amount of FVII.E368. The method of embodiment 367, wherein said method increases the generation of thrombin in the presence of TFPI.E369. The method of any one of embodiments 359-368, comprising administering said antibody or antigen-binding fragment thereof, or pharmaceutical composition, intravenously.E370. The method of any one of embodiments 359-368, comprising administering said antibody or antigen-binding fragment thereof, or pharmaceutical composition, subcutaneously.E371 . The method of any one of embodiments 359-368, wherein said antibody or antigen-binding fragment thereof, or pharmaceutical composition, is administered once every 3 days, once every 4 days, once every 5 days, once every 6 days, once a week, or twice a week.E372. The antibody or antigen-binding fragment thereof of any one of embodiments 1-347 and357, or the pharmaceutical composition of embodiment 358, for use as a medicament.E373. The antibody or antigen-binding fragment thereof of any one of embodiments 1-347 and357, or the pharmaceutical composition of embodiment 358 for use in reducing the activity of TFPI in a subject.E374. The antibody or antigen-binding fragment thereof of any one of embodiments 1-347 and 357, or the pharmaceutical composition of embodiment 357 for use in shortening bleeding time in a subject. E375. The antibody or antigen-binding fragment, or pharmaceutical composition of any one of embodiments 372-374, wherein said subject is a human.E376. The antibody or antigen-binding fragment, or pharmaceutical composition of any one of embodiments 372-375, wherein said subject suffers from or is susceptible to a deficiency in blood coagulation.E377. The antibody or antigen-binding fragment, or pharmaceutical composition of any one of embodiments 372-375, wherein said subject suffers from or is susceptible to hemophilia A, B or C. E378. The antibody or antigen-binding fragment, or pharmaceutical composition of any one of embodiments 372-375, wherein said subject suffers from or is susceptible to hemophilia A or B. E379. The antibody or antigen-binding fragment, or pharmaceutical composition of any one of embodiments 372-375, wherein said subject suffers from or is susceptible to von Willebrand Disease (vWD).E380. The antibody or antigen-binding fragment, or pharmaceutical composition of any one of embodiments 372-375, wherein said subject suffers from or is susceptible to a platelet disorder. E381 . Use of the antibody or antigen-binding fragment thereof of any one of embodiments 1-348 and 357, or the pharmaceutical composition of embodiment 358, for reducing the activity of TFPI in a subject.E382. Use of the antibody or antigen-binding fragment thereof of any one of embodiments 1-348 and 357, or the pharmaceutical composition of embodiment 358, in the manufacture of a medicament for reducing the activity of TFPI in a subject.E383. Use of the antibody or antigen-binding fragment thereof of any one of embodiments 1-348 and 357, or the pharmaceutical composition of embodiment 358, for shortening bleeding time in a subject.E384. Use of the antibody or antigen-binding fragment thereof of any one of embodiments 1 -348 and 357, or the pharmaceutical composition of embodiment 358, in the manufacture of a medicament for shortening bleeding time in a subject.E385. The use of any one of embodiments 381-384, wherein said subject is a human.E386. The use of any one of embodiments 381-384, wherein said subject suffers from or is susceptible to a deficiency in blood coagulation.E387. The use of any one of embodiments 381-384, wherein said subject suffers from or is susceptible to hemophilia A, B or C.E388. The use of any one of embodiments 381-384, wherein said subject suffers from or is susceptible to hemophilia A or B. E389. The use of any one of embodiments 381-384, wherein said subject suffers from or is susceptible to von Willebrand Disease (vWD).E390. The use of any one of embodiments 381 -384, wherein said subject suffers from or is susceptible to a platelet disorder.Brief Description of the Drawings[9] FIGS. 1A-1 F are drawings showing the co-crystal structures of various anti-TFPI antibodies and the K2 domain of TFPI. In particular, as shown in FIG. 1 F, exemplary antibodies disclosed herein, TFPI-23, TFPI-24, and 4D8, all bind to non-overlapping epitopes of the K2 domain as compared to other reference antibodies. TFPI-106 binds to the same site as TFPI-23, and TFPI- 118 bind to the same site as TFPI-24. "R&D" or "R&D Fab" refers to antibody Mab 2974 from R&D Systems. Novo2021 antibody is also called "hz4F36." "Clone 23" refers to TFPI-23; "clone 24" refers to TFPI-24.

[10] FIGS. 2A-2E are diagrams showing the interactions between epitopes residues within the PC- domain of TFPI and paratope residues from various anti-TFPI antibodies. "R&D" or "R&D Fab" refers to Mab 2974 from R&D Systems. "Clone 23" refers to TFPI-23; "clone 24" refers to TFPI-24.[1 1] FIGS. 3A-3E show the in vivo efficacies of various anti-TFPI antibodies in a mouse injury model. FIGS. 3A and 3B show the duration in decreasing bleeding in Hemophilia A Factor VIII deficient (FVIII - / -) mice when 2A8-200 and 2A8 antibodies (used as reference antibodies in this study) were administered. FIG. 3C shows the duration of effect in Hemophilia A mice when TFPI 4D8 (control), TFPI-21 , TFPI-23, and TFPI-24 antibodies were administered. FIGS. 3D and 3E show the duration of Hemophilia A mice when TFPI-106 and TFPI-1 18 antibodies wereadministered. Antibodies were administered to hemophilia A mice (FVIII - / -) by intravenous injection at 6 mg / kg at the indicated time points (hours (h)) before injury. Total volume of blood loss (μΙ_) was then measured after tail transection. Vehicle (saline) treated hemophilia A mice served as a control. All measurements are presented as mean ± SEM. * = P < 0.05. FVIII + / + (wild-type) mice received saline, n = 5 / group.

[12] FIG. 4 shows the duration of bleeding in Hemophilia B mice after tail transection when TFPI- 106 antibody was administered. Antibodies were administered to hemophilia B mice by intravenous injection at 6 mg / kg at the indicated time points (hours (h)) before injury. Total volume of blood loss (μΙ_) was then measured after tail transection. Vehicle (saline) treated hemophilia A mice served as a control. All measurements are presented as mean ± SEM. * = P < 0.05. n = 4-5 / group.

[13] FIG. 5, comprising panels A and B, each of which comprises six panels (FIG. 5A, 1 through 6 and FIG. 5B, 1 through 6) shows microphotographs of intravital microscopy (IVM) demonstrating that TFPI is detected in the platelet thrombus and along the endothelium in vivo at the site of vessel injury in a wild type mouse. Figure 5A shows the increase in platelet thrombus at the site of injury as detected using Dylight 649-labeled CD42c that binds GP1b on platelets. The presence or absence of platelets is demonstrated by the fluorescence signal detected in panel 1 (0 sec); panel 2 (15 sec); panel 3 (30 sec); panel 4 (60 sec); panel 5 (90 sec); and panel 6 (120 sec). Alexa 488- labeled negative control IgG was also administered, and no fluorescence was detected. Figure 5B, comprising panels 1-6, shows microphotographs of IVM demonstrating that TFPI is present in the platelet thrombus and along the endothelium after laser induced vessel injury in wild type mice. Alexa 488-labeled TFPI (green signal shown as gray) is not detected at 0 seconds (FIG. 5B, panel 1) and a faint signal can be seen at 15 seconds (FIG. 5B, panel 2). At 30 seconds (FIG. 5B, panel 3) the green fluorescence signal has increased and a faint red signal (Dylight 649-labeled CD42c) can be seen indicating detection of platelet accumulation at approximately the same site where TFPI is detected. FIG. 5B, panel 4 (60 seconds) shows strong green and red fluorescent signals (both light gray where red fluorescence can be seen to the left of the vessel injury site and green signal is primarily detected towards the right side of the injury site) demonstrating both platelet accumulation and TFPI are detected at the site of injury. FIG. 5B, panel 5, shows both red(platelets) and green (TFPI) fluorescence signals at the site of injury by 60 seconds where both signals are greater than at 30 seconds. FIG. 5B, panel 6, shows decreased red signal (platelets) and decreased green signal (TFPI) both still detectable at the site of injury at 120 seconds.

[14] FIGURE 6A is a graph showing the hemostatic effect of TFPI-106 in hemophilia A mice after laser induced vessel injury as assessed using IVM where the amount of platelet thrombus is expressed as the area under the curve (AUC) (* = P<0.005 is indicated). FIG. 6A shows the accumulation of platelets at the site of injury in wild type mice (WT) at 0.5 hours post-injury where the mice received only saline control compared with the lack of platelet accumulation in the hemophilia A mouse at 0.5 hours where saline was administered. Platelet accumulation was detected in hemophilia A mice at 0.5 hours where recombinant factor VIII (rFVIII) or TFPI-106 was administered. The thrombus accumulation effect was still detected at 168 hours in hemophilia A mice administered TFPI-106.

[15] FIGURE 6B is a graph showing the hemostatic effect of TFPI-106 in hemophilia A mice after laser induced vessel injury as assessed using IVM where the amount of fibrin generation is expressed as the area under the curve (AUC) (* = P<0.005 is indicated). FIG. 6B shows the generation of fibrin at the site of injury in wild type mice (WT) at 0.5 hours post-injury where the mice received only saline control compared with the lack of detectable fibrin generation in the hemophilia A mouse at 0.5 hours where saline was administered. Fibrin generation was detected in hemophilia A mice at 0.5 hours where recombinant factor VIII (rFVIII) or TFPI-106 was administered. The fibrin generation effect was still detected at 168 hours in hemophilia A mice administered TFPI-106.

[16] FIGURE 7 depicts a graph showing the effect on a thrombin generation assay (TGA) of administration of TFPI-106 and recombinant factor Vila (rFVIIa) in severe hemophilia A plasma in the presence of 1 pm tissue factor and 4 μΜ phospholipids. The graph shows the thrombograms for hemophilia A plasma with TFPI-106 alone (16 μg ml) and in combination with rFVIIa (20 μg ml; 2 μg ml; or 0.2 μg ml). Also shown are the thrombograms for hemophilic A plasma and non- hemophilic plasma with neither TFPI-106 nor rFVIIa.

[17] FIGURE 8A depicts thrombograms showing the effect on thrombin generation in the presence of 1 pM tissue factor and 4 μΜ phospholipids in hemophilia A plasma in the presence of TFPI-106 with or without rFVIIa or in the presence of rFVIIa only. Non-hemophilic plasma is included as a control.

[18] FIGURE 8B depicts thrombograms showing the effect on thrombin generation in the presence of three Bethesda Units (3 BU) of an inhibitor in citrated platelet poor hemophilia A plasma in the presence of TFPI-106 with or without rFVIIa or in the presence of rFVIIa only. Non- hemophilic plasma is included as a control. Also included a control non-hemophilic plasma to which TFPI-106 (16 g / ml) was added.

[19] FIGURE 8C depicts thrombograms showing the effect on thrombin generation in the presence of three Bethesda Units (3 BU) of an inhibitor in citrated platelet poor hemophilia B plasma in the presence of TFPI-106 with or without rFVIIa or in the presence of rFVIIa only. Non- hemophilic plasma is included as a control. Also included a control non-hemophilic plasma to which TFPI-106 (16 g / ml) was added.

[20] FIG. 9A shows the effect on blood loss compared to control of administering antibody TFPI- 106 (6 mg / kg) and separately recombinant Factor VIII (200 units / kg) to hemophilia A mice immediately after tail transection. FIG. 9B shows the effect on blood loss compared to control of administering three different doses of antibody TFPI-106 (6 mg / kg) and separately recombinant Factor VIII (200 units / kg) to hemophilia A mice 2 minutes after tail transection.

[21] FIG. 10A shows the effect of different concentrations of TFPI 106 compared to recombinant Factor VIII on clotting time of whole blood from a human patient with severe hemophilia A. FIG. 10B shows the effect of different concentrations of TFPI 106 compared to recombinant Factor VIII on peak thrombin generation in platelet rich plasma from a human patient with severe hemophilia A.

[22] FIG. 1 1A shows the effect of different concentrations of TFPI 106 on clotting time of whole blood from a human patient with severe hemophilia A and inhibitors to FVIII. FIG. 11 B shows the effect of different concentrations of TFPI 106 on peak thrombin generation in platelet rich plasma from a human patient with severe hemophilia A and inhibitors to FVIII. FIG. 1 1C shows the effect of different concentrations of TFPI 106 on clotting time of platelet poor plasma from a human patient with severe hemophilia A and inhibitors to FVIII.

[23] FIG. 12A shows the effect of different concentrations of TFPI 106 compared to recombinant Factor VIII on clotting time of whole blood from a human patient with moderate hemophilia A. FIG. 12B shows the effect of different concentrations of TFPI 106 compared to recombinant Factor VIII on peak thrombin generation in platelet rich plasma from a human patient with moderate hemophilia A. FIG. 12C shows the effect of different concentrations of TFPI 106 on clotting time of platelet poor plasma from a human patient with moderate hemophilia A.

[24] FIG. 13A shows the effect of different concentrations of TFPI 106 compared to recombinant Factor IX on clotting time of whole blood from a human patient with moderate hemophilia B. FIG. 13B shows the effect of different concentrations of TFPI 106 compared to recombinant Factor IX on peak thrombin generation in platelet rich plasma from a human patient with moderate hemophilia B. FIG. 13C shows the effect of different concentrations of TFPI 106 on clotting time of platelet poor plasma from a human patient with moderate hemophilia B.

[25] FIG. 14A shows the effect of different concentrations of TFPI 106 compared to recombinant Factor VIII on clotting time of whole blood from multiple human patients with hemophilia A. FIG. 14B shows the effect of different concentrations of TFPI 106 compared to recombinant Factor VIII on peak thrombin generation in platelet rich plasma from multiple human patients with hemophilia A. FIG. 14C shows the effect of different concentrations of TFPI 106 on clotting time of platelet poor plasma from multiple human patients with hemophilia B.Detailed Description of the Invention1. OVERVIEW

[26] As noted above, patients with hemophilia have some ability to stop bleeds through their intact extrinsic pathway; however the extrinsic pathway is insufficient to provide protection because it is rapidly shut down by the Tissue Factor Pathway Inhibitor (TFPI). Blocking / neutralizing TFPI inhibition in these patients can compensate for an inadequate FXa generation and normalize the bleeding diathesis. Accordingly, disclosed and exemplified herein are antibodies and antigen- binding fragments thereof that specifically bind to TFPI and inhibit the activity thereof.2. DEFINITIONS

[27] By "reducing the activity of TFPI" is meant that the antibody or antigen-binding fragment thereof can: (i) decrease clotting time when compared to the clotting time in the absence of the antibody as measured by, e.g., a plasma based dilute prothrombin time assay; (ii) reduce clotting time in whole blood as compared to the clotting time in the absence of the antibody as measured by, e.g., thromboelastrography or rotational thromboelastometry; (iii) increase thrombin generation; (iv) increase FXa activity in the presence of TFPI; (v) enhance platelet accumulation in the presence of TFPI; (vi) increase fibrin generation in the presence of TFPI; or (vii) any combination thereof. The inhibitory activities of an antibody or antigen-binding fragment can, but need not be dose-dependent (e.g., causing a dose-dependent decrease in clotting time as measured in a plasma based dilute prothrombin time assay).

[28] Further, as disclosed and exemplified herein, co-crystal structures of anti-TFPI antibodies and the Kunitz Domain 2 (K2 domain) of TFPI were obtained. Structural analysis shows that the exemplary antibodies of the invention recognize unique epitopes of TFPI, as compared to other publicly disclosed TFPI antibodies (which were used as references antibodies in the Examples). For example, as shown in Figures 1A-1 F and Figures 2A-2E, as compared to several reference TFPI antibodies (R&D (Mab2479) Fab, Novo2021 (also called hz4F36) Fab, 2A8 Fab), TFPI-23, TFPI-24, and 4D8 antibodies bind to non-overlapping sites in the K2 domain of TFPI.

[29] Accordingly, in certain embodiments, the antibodies (and antigen-binding fragments) disclosed herein recognize a unique epitope of TFPI, located at the K2 domain of TFPI. Based on the co-crystal structure and computational alanine scan, this epitope comprises three residues that are important for antibody-antigen interactions: Ile105, Arg107, and Leu131 (according to the numbering of human TFPI as shown in SEQ ID NO: 2). Mutating these three residues to Alanine results in loss of antibody binding. For example, antibodies TFPI-23 and its variants (e.g., TFPI-106 and TFPI-107) all recognize this epitope.

[30] In certain embodiments, the recognition of key epitope residues disclosed herein allows the antibodies (and antigen-binding fragments thereof) to reduce the activity of TFPI. In particular, the crystal structure shows that the K2 domain of TFPI adopts a cone-shaped structure, with the tip of the cone (especially Arg107) binding to FXa. TFPI-23 and TFPI-24 both recognize the tip of this cone-shaped region and block the binding of TFPI to FXa. Antibody 4D8 recognizes a different epitope in K2 domain. Although not interacting directly with residues at the tip of the cone, 4D8 nonetheless blocks the binding of TFPI to FXa. Table 15 summarizes the non-overlapping epitope residues recognized by the exemplary antibodies disclosed herein, as compared to other publicly known TFPI antibodies.

[31] Further, in certain embodiments, antibodies and antigen-binding fragments thereof disclosed herein have demonstrated desirable pharmacological activities and pharmacokinetic properties for treatment of coagulation deficiencies (such as hemophilia) and for reducing bleeding time.

[32] An antibody that "preferentially binds" or "specifically binds" (used interchangeably herein) to an epitope is a term well understood in the art, and methods to determine such specific or preferential binding are also well known in the art. A molecule is said to exhibit "specific binding" or "preferential binding" if it reacts or associates more frequently, more rapidly, with greater duration and / or with greater affinity with a particular cell or substance than it does with alternative cells or substances. An antibody "specifically binds" or "preferentially binds" to a target if it binds with greater affinity, avidity, more readily, and / or with greater duration than it binds to other substances. Also, an antibody "specifically binds" or "preferentially binds" to a target if it binds with greater affinity, avidity, more readily, and / or with greater duration to that target in a sample than it binds to other substances present in the sample. For example, an antibody that specifically or preferentially binds to a TFPI epitope is an antibody that binds this epitope with greater affinity, avidity, more readily, and / or with greater duration than it binds to other TFPI epitopes or non-TFPI epitopes. It is also understood by reading this definition, for example, that an antibody (or moiety or epitope) which specifically or preferentially binds to a first target may or may not specifically or preferentially bind to a second target. As such, "specific binding" or "preferential binding" does not necessarily require (although it can include) exclusive binding. Generally, but not necessarily, reference to binding means preferential binding. "Specific binding" or "preferential binding" includes a compound, e.g., a protein, a nucleic acid, an antibody, and the like, which recognizes and binds to a specific molecule, but does not substantially recognize or bind other molecules in a sample. For instance, an antibody or a peptide receptor which recognizes and binds to a cognate ligand or binding partner (e.g., an anti-TFPI antibody that binds TFPI) in a sample, but does not substantially recognize or bind other molecules in the sample, specifically binds to that cognate ligand or binding partner. Thus, under designated assay conditions, the specified binding moiety (e.g., an antibody or an antigen-binding portion thereof or a receptor or a ligand binding portion thereof) binds preferentially to a particular target molecule and does not bind in a significant amount to other components present in a test sample.

[33] A variety of assay formats may be used to select an antibody or peptide that specifically binds a molecule of interest. For example, solid-phase ELISA immunoassay, immunoprecipitation, Biacore™ (GE Healthcare, Piscataway, NJ), KinExA, fluorescence-activated cell sorting (FACS), Octet™ (ForteBio, Inc., Menlo Park, CA) and Western blot analysis are among many assays that may be used to identify an antibody that specifically reacts with an antigen or a receptor, or ligand binding portion thereof, that specifically binds with a cognate ligand or binding partner. Typically, a specific or selective reaction will be at least twice the background signal or noise, more typically more than 10 times background, even more typically, more than 50 times background, more typically, more than 100 times background, yet more typically, more than 500 times background, even more typically, more than 1000 times background, and even more typically, more than 10,000 times background. Also, an antibody is said to "specifically bind" an antigen when the equilibrium dissociation constant (KD) is≤ 7 nM.

[34] The term "binding affinity" is herein used as a measure of the strength of a non-covalent interaction between two molecules, e.g., and antibody, or fragment thereof, and an antigen. The term "binding affinity" is used to describe monovalent interactions (intrinsic activity).

[35] Binding affinity between two molecules, e.g. an antibody, or fragment thereof, and an antigen, through a monovalent interaction may be quantified by determination of the dissociation constant (KD). In turn, KD can be determined by measurement of the kinetics of complex formation and dissociation using, e.g., the surface plasmon resonance (SPR) method (Biacore). The rate constants corresponding to the association and the dissociation of a monovalent complex are referred to as the association rate constants ka (or kon) and dissociation rate constant kd (or koff), respectively. KD is related to ka and kd through the equation KD = kd I ka. The value of the dissociation constant can be determined directly by well-known methods, and can be computed even for complex mixtures by methods such as those, for example, set forth in Caceci et al. (1984, Byte 9: 340-362). For example, the KD may be established using a double-filter nitrocellulose filter binding assay such as that disclosed by Wong & Lohman (1993, Proc. Natl. Acad. Sci. USA 90: 5428-5432). Other standard assays to evaluate the binding ability of ligands such as antibodies towards target antigens are known in the art, including for example, ELISAs, Western blots, RIAs, and flow cytometry analysis, and other assays exemplified elsewhere herein. The binding kinetics and binding affinity of the antibody also can be assessed by standard assays known in the art, such as Surface Plasmon Resonance (SPR), e.g. by using a Biacore™ system, or KinExA.

[36] A competitive binding assay can be conducted in which the binding of the antibody to the antigen is compared to the binding of the target by another ligand of that target, such as another antibody or a soluble receptor that otherwise binds the target. The concentration at which 50% inhibition occurs is known as the K,. Under ideal conditions, the K, is equivalent to KD. The Ki value will never be less than the KD, so measurement of Kj can conveniently be substituted to provide an upper limit for KD.

[37] Following the above definition, binding affinities associated with different molecular interactions, e.g., comparison of the binding affinity of different antibodies for a given antigen, may be compared by comparison of the KD values for the individual antibody / antigen complexes. KD values for antibodies or other binding partners can be determined using methods well established in the art. One method for determining the KD is by using surface plasmon resonance, typically using a biosensor system such as a Biacore® system.

[38] Similarly, the specificity of an interaction may be assessed by determination and comparison of the KD value for the interaction of interest, e.g., a specific interaction between an antibody and an antigen, with the KD value of an interaction not of interest, e.g., a control antibody known not to bind TFPI.

[39] An antibody that specifically binds its target may bind its target with a high affinity, that is, exhibiting a low KD as discussed above, and may bind to other, non-target molecules with a lower affinity. For example, the antibody may bind to non-target molecules with a KD of 1 x 10"6M or more, more preferably 1 x 10"5 M or more, more preferably 1 x 10"4 M or more, more preferably 1 x 10"3 M or more, even more preferably 1 x 10'2 M or more. An antibody of the invention is preferably capable of binding to its target with an affinity that is at least two-fold, 10-fold, 50-fold, 100-fold 200- fold, 500-fold, 1 , 000-fold or 10,000-fold or greater than its affinity for binding to another non-TFPI molecule.

[40] In general, a TFPI antibody needs to bind to TFPI with high affinity, in order to effectively reduce the activities of TFPI. However, when the binding affinity of an antibody is too high, the antibody can quickly get internalized and degraded by a host cell. This could potentially result in a short half-life and repeated injections. For example, antibody TFPI-23 shows a lower binding affinity (Kd) as compared to TFPI-24, and under certain circumstances, appears more desirable for clinical uses because it has a lower internalization rate and longer half-life. Accordingly, binding affinities (Kd) from 5x10"7 M to about 5x10"11 M, in particular from about 1x10"8 M to about 1x10"10 M, are generally desirable, especially for treating a chronic condition (e.g., hemophilia) that require repeated injections. Without wishing to be bound by any particular theory, this affinity range is believed to strike a balance between (i) binding affinities that are needed for effectively inhibiting the activities of TFPI, and (ii) a longer half-life and reduced antibody internalization.

[41] Specific amino acid residue positions in TFPI are numbered according to SEQ ID NO: 2 (human TFPIa K1 K2K3). However, the present invention is not limited to SEQ ID NO: 2.Corresponding residues from other TFPI homologs, isoforms, variants, or fragments can be identified according to sequence alignment or structural alignment that is known in the art. For example, alignments can be done by hand or by using well-known sequence alignment programs such as ClustalW2, or "BLAST 2 Sequences" using default parameters. For example, Arg107 of SEQ ID NO: 2 corresponds to Arg104 of Mouse TFPI K1 K2 (SEQ ID NO: 4).

[42] An "antigen-binding fragment" of an antibody refers to a fragment of a full-length antibody that retains the ability to specifically bind to an antigen (preferably with substantially the same binding affinity). Examples of an antigen-binding fragment includes (i) a Fab fragment, a monovalent fragment consisting of the VL, VH, CL and CH1 domains; (ii) a F(ab')2 fragment, a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) a Fd fragment consisting of the VH and CH1 domains; (iv) a Fv fragment consisting of the VL and VH domains of a single arm of an antibody, (v) a dAb fragment (Ward et al., (1989) Nature341 :544-546), which consists of a VH domain; and (vi) an isolated complementarity determining region (CDR), disulfide-linked Fvs (dsFv), and anti-idiotypic (anti-Id) antibodies and intrabodies. Furthermore, although the two domains of the Fv fragment, VL and VH, are coded for by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the VL and VH regions pair to form monovalent molecules (known as single chain Fv (scFv)); see e.g., Bird et al. Science 242:423-426 (1988) and Huston et al. Proc. Natl. Acad. Sci. USA 85:5879-5883 (1988)). Other forms of single chain antibodies, such as diabodies are also encompassed. Diabodies are bivalent, bispecific antibodies in which VH and VL domains are expressed on a single polypeptide chain, but using a linker that is too short to allow for pairing between the two domains on the same chain, thereby forcing the domains to pair with complementary domains of another chain and creating two antigen-binding sites (see e.g., Holliger et al. Proc. Natl. Acad. Sci. USA 90:6444-6448 (1993); Poljak et al., 1994, Structure 2:1 121-1 123).

[43] An antibody "variable domain" refers to the variable region of the antibody light chain (VL) or the variable region of the antibody heavy chain (VH), either alone or in combination. As known in the art, the variable regions of the heavy and light chains each consist of four framework regions (FR) connected by three complementarity determining regions (CDRs), and contribute to the formation of the antigen-binding site of antibodies.

[44] Residues in a variable domain are numbered according Kabat, which is a numbering system used for heavy chain variable domains or light chain variable domains of the compilation of antibodies. See, Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD. (1991)). Using this numbering system, the actual linear amino acid sequence may contain fewer or additional amino acids corresponding to a shortening of, or insertion into, a FR or CDR of the variable domain. For example, a heavy chain variable domain may include a single amino acid insert (residue 52a according to Kabat) after residue 52 of H2 and inserted residues (e.g. residues 82a, 82b, and 82c, according to Kabat) after heavy chain FR residue 82. The Kabat numbering of residues may be determined for a given antibody by alignment at regions of homology of the sequence of the antibody with a "standard" Kabat numbered sequence. Various algorithms for assigning Kabat numbering are available. The algorithm implemented in the 2012 release of Abysis (www.abysis.org) is used herein to assign Kabat numbering to variable regions unless otherwise noted.

[45] Specific amino acid residue positions in an antibody (such as paratope residues disclosed herein) are also numbered according to Kabat.

[46] "Complementarity Determining Regions" (CDRs) can be identified according to the definitions of the Kabat, Chothia, the accumulation of both Kabat and Chothia, AbM, contact, and / or conformational definitions or any method of CDR determination well known in the art. See, e.g., Kabat et al., 1991 , Sequences of Proteins of Immunological Interest, 5th ed. (hypervariable regions); Chothia et al., 1989, Nature 342:877-883 (structural loop structures). AbM definition of CDRs is a compromise between Kabat and Chothia and uses Oxford Molecular's AbM antibody modeling software (Accelrys®).The "contact" definition of CDRs is based on observed antigen contacts, set forth in MacCallum et al., 1996, J. Mol. Biol., 262:732-745. The "conformational" definition of CDRs is based on residues that make enthalpic contributions to antigen binding (see, e.g., Makabe et al., 2008, Journal of Biological Chemistry, 283: 1 156-1 166). Still other CDR boundary definitions may not strictly follow one of the above approaches, but will nonetheless overlap with at least a portion of the Kabat CDRs, although they may be shortened or lengthened in light of prediction or experimental findings that particular residues or groups of residues or even entire CDRs do not significantly impact antigen binding. As used herein, a CDR may refer to CDRs defined by any approach known in the art, including combinations of approaches.

[47] In the Examples (see Tables 3 and 4), the CDRs are defined as follows (numbering according to Kabat; H: heavy chain; L: light chain):CDR-H1 : H26-H35B; CDR-H2: H50-H65; CDR-H3: H95-H102 CDR-L1 : L24-L34; CDR-L2: L50-L56; CDR-L3: L89-L97

[48] "Framework" (FR) residues are antibody variable domain residues other than the CDR residues. A VH or VL domain framework comprises four framework sub-regions, FR1 , FR2, FR3 and FR4, interspersed with CDRs in the following structure: FR1 - CDR1 - FR2 - CDR2 - FR3 - CDR3 - FR4. In the Examples (see Tables 3 and 4), FR residues include the following (numbering according to Kabat; H: heavy chain; L: light chain):FR1 FR2 FR3 FR4Heavy Chain H1-H25 H36-H49 H66-H94 H103-H1 13Light Chain L1-L23 L35-L49 L57-L88 L98-L107

[49] An "epitope" refers to the area or region of an antigen (Ag) to which an antibody specifically binds, e.g., an area or region comprising residues that interacts with the antibody (Ab). Epitopes can be linear or conformational. In a linear epitope, all of the points of interaction between the protein and the interacting molecule (such as an antibody) occur linearly along the primary amino acid sequence of the protein. A "nonlinear epitope" or "conformational epitope" comprises noncontiguous polypeptides (or amino acids) within the antigenic protein to which an antibody specific to the epitope binds. The term "epitope" as used herein, is defined as a portion of an antigen to which an antibody can specifically bind as determined by any method well known in the art, for example, by conventional immunoassays. Alternatively, during the discovery process, the generation and characterization of antibodies may elucidate information about desirable epitopes. From this information, it is then possible to competitively screen antibodies for binding to the same epitope. An approach to achieve this is to conduct competition and cross-competition studies to find antibodies that compete or cross-compete with one another for binding to TFPI. That is, the antibodies compete for binding to the antigen such that the antibodies compete for binding to the antigen-binding site of an anti-TFPI antibody of the disclosure.

[50] The term "paratope" is derived from the above definition of "epitope" by reversing the perspective, and refers to the area or region of an antibody molecule which is involved in binding of an antigen, e.g., an area or region comprising residues that interacts with the antigen. A paratope may be linear or conformational (such as discontinuous residues in CDRs).

[51] The epitope / paratope for a given antibody / antigen binding pair can be defined and characterized at different levels of detail using a variety of experimental and computational epitope mapping methods. The experimental methods include mutagenesis, X-ray crystallography, Nuclear Magnetic Resonance (NMR) spectroscopy, Hydrogen / deuterium exchange Mass Spectrometry (HX-MS) and various competition binding methods. As each method relies on a unique principle, the description of an epitope is intimately linked to the method by which it has been determined. Thus, the epitope / paratope for a given antibody / antigen pair will be defined differently depending on the mapping method employed.

[52] At its most detailed level, the epitope / paratope for the interaction between the Ab and the Ab can be defined by the spatial coordinates defining the atomic contacts present in the Ag-Ab interaction, as well as information about their relative contributions to the binding thermodynamics. At one level, an epitope / paratope residue can be characterized by the spatial coordinates defining the atomic contacts between the Ag and Ab. In one aspect, the a epitope / paratope residue can be defined by a specific criterion, e.g., distance between atoms in the Ab and the Ag (e.g., a distance of equal to or less than 4 A from a heavy atom of the cognate antibody and a heavy atom of the antigen ("contact" residues)). In another aspect, an epitope / paratope residue can be characterized as participating in a hydrogen bond interaction with the cognate antibody / antigen, or with a water molecule that is also hydrogen bonded to the cognate antibody / antigen (water-mediated hydrogen bonding). In another aspect, an epitope / paratope residue can be characterized as forming a salt bridge with a residue of the cognate antibody / antigen. In yet another aspect, an epitope / paratope residue can be characterized as a residue having a non-zero change in buried surface area (BSA) due to interaction with the cognate antibody / antigen. At a further less detailed level,epitope / paratope can be characterized through function, e.g., by competition binding with other Abs. The epitope / paratope can also be defined more generically as comprising amino acid residues for which substitution by another amino acid will alter the characteristics of the interaction between the Ab and Ag (e.g. alanine scanning).

[53] In the context of an X-ray derived crystal structure defined by spatial coordinates of a complex between an antibody, e.g., a Fab fragment or two Fab fragments, and its antigen, unless otherwise specified, an epitope residue refers to a TFPI residue (i) having a heavy atom (i.e., a non-hydrogen atom) that is within a distance of 4 A from a heavy atom of the cognate antibody (also called "contact" residues); (ii) participating in a hydrogen bond with a residue of the cognate antibody, or with a water molecule that is also hydrogen bonded to the cognate antibody (water- mediated hydrogen bonding), (iii) participating in a salt bridge to a residue of the cognate antibody, and / or (iv) having a non-zero change in buried surface area (BSA) due to interaction with the cognate antibody. In general, a cutoff is imposed for BSA to avoid inclusion of residues that have minimal interactions. Therefore, unless otherwise specified, epitope residues under category (iv) are selected if it has a BSA of 20 A2 or greater, or is involved in electrostatic interactions when the antibody binds to TFPI. Similarly, in the context of an X-ray derived crystal structure, unless otherwise specified or contradicted by context, a paratope residue, refers to an antibody residue (i) having a heavy atom (i.e., a non-hydrogen atom) that is within a distance of 4 A from a heavy atom of TFPI (also called "contact" residues), (ii) participating in a hydrogen bond with a TFPI residue, or with a water molecule that is also hydrogen bonded to TFPI (water-mediated hydrogen bonding), (iii) participating in a salt bridge to a residue of TFPI, and / or (iv) having a non-zero change in buried surface area due to interaction with TFPI. Again, unless otherwise specified, paratope residues under category (iv) are selected if it has a BSA of 20 A2 or greater, or is involved in electrostatic interactions when antibody binds to TFPI.

[54] From the fact that descriptions and definitions of epitopes, dependent on the epitope mapping method used, and obtained at different levels of detail, it follows that comparison of epitopes for different Abs on the same Ag can similarly be conducted at different levels of detail. For example, epitopes described on the amino acid level, e.g., determined from an X-ray structure, are said to be identical if they contain the same set of amino acid residues. Epitopes are said to be separate (unique) if no amino acid residue is shared by the epitopes. Epitopes characterized by competition binding are said to be overlapping if the binding of the corresponding antibodies are mutually exclusive, i.e., binding of one antibody excludes simultaneous or consecutive binding of the other antibody; and epitopes are said to be separate (unique) if the antigen is able to accommodate binding of both corresponding antibodies simultaneously.

[55] The epitope and paratope for a given antibody / antigen pair may be identified by routine methods. For example, the general location of an epitope may be determined by assessing the ability of an antibody to bind to different fragments or variant TFPI polypeptides as more fully described previously elsewhere herein. Specific residues within TFPI that make contact with specific residues within an antibody may also be determined using routine methods, such as those described in the examples. For example, antibody / antigen complex may be crystallized. The crystal structure may be determined and used to identify specific sites of interaction between the antibody and antigen.

[56] The term "compete", as used herein with regard to an antibody, means that binding of a first antibody, or an antigen-binding portion thereof, to an antigen reduces the subsequent binding of the same antigen by a second antibody or an antigen-binding portion thereof. In general, the binding a first antibody creates steric hindrance, conformational change, or binding to a common epitope (or portion thereof), such that the binding of the second antibody to the same antigen is reduced. Standard competition assays may be used to determine whether two antibodies compete with each other. One suitable assay for antibody competition involves the use of the Biacore technology, which can measure the extent of interactions using surface plasmon resonance (SPR) technology, typically using a biosensor system (such as a BIACORE® system). For example, SPR can be used in an in vitro competitive binding inhibition assay to determine the ability of one antibody to inhibit the binding of a second antibody. Another assay for measuring antibody competition uses an ELISA-based approach. Furthermore, a high throughput process for "binning" antibodies based upon their competition is described in International Patent Application No.WO2003 / 48731. Competition is present if one antibody (or fragment) reduces the binding of another antibody (or fragment) to TFPI. For example, a sequential binding competition assay may be used, with different antibodies being added sequentially. The first antibody may be added to reach binding that is close to saturation. Then, the second antibody is added. If the binding of second antibody to TFPI is not detected, or is significantly reduced (e.g., at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% reduction) as compared to a parallel assay in the absence of the first antibody (which value can be set as 100%), the two antibodies are considered as competing with each other. An exemplary antibody competition assay (and overlapping epitope analysis) by SPR is provided in Example 6.

[57] An anti-TFPI antibody of the disclosure may have the ability to compete or cross-compete with another antibody of the disclosure for binding to TFPI as described herein. For example, an antibody of the disclosure may compete or cross-compete with antibodies described herein for binding to TFPI, or to a suitable fragment or variant of TFPI that is bound by the antibodies disclosed herein.

[58] That is, if a first anti-TFPI antibody competes with a second antibody for binding to TFPI , but it does not compete where the second antibody is first bound to TFPI, it is deemed to "compete" with the second antibody (also referred to as unidirectional competition). Where an antibody competes with another antibody regardless of which antibody is first bound to TFPI, then the antibody "cross-competes" for binding to TFPI with the other antibody. Such competing or cross- competing antibodies can be identified based on their ability to compete / cross-compete with a known antibody of the disclosure in standard binding assays. For example, SPR, e.g., by using a Biacore™ system, ELISA assays or flow cytometry may be used to demonstrate competition / cross- competition. Such competition / cross-competition may suggest that the two antibodies bind to identical, overlapping or similar epitopes.

[59] An anti-TFPI antibody of the disclosure may therefore be identified by a method that comprises a binding assay which assesses whether or not a test antibody is able to compete / cross- compete with a reference antibody of the disclosure (e.g.,TFPI-3, TFPI-21 , TFPI-23, TFPI-24, TFPI-26, TFPI-106, TFPI-107, TFPI-108, TFPI-109, TFPI-1 10, TFPI-1 1 1 , TFPI-1 12, TFPI-1 13, TFPI-1 14, 4D8, 6B7.c5, 7A4.D9) for a binding site on the target molecule.

[60] An "Fc fusion" protein is a protein wherein one or more polypeptides are operably linked to an Fc polypeptide. An Fc fusion combines the Fc region of an immunoglobulin with a fusion partner.

[61] The binding affinity of an antibody can be expressed as Kd value, which refers to the dissociation rate of a particular antigen-antibody interaction. Kd is the ratio of the rate of dissociation, also called the "off-rate (koff)", to the association rate, or "on- rate (kon)". Thus, Kd equals koff / kon and is expressed as a molar concentration (M), and the smaller the Kd, the stronger the affinity of binding. Kd values for antibodies can be determined using methods well established in the art. One exemplary method for measuring Kd is surface plasmon resonance (SPR), typically using a biosensor system such as a BIACORE® system. BIAcore kinetic analysis comprises analyzing the binding and dissociation of an antigen from chips with immobilized molecules (e.g. molecules comprising epitope binding domains), on their surface. Another method for determining the Kd of an antibody is by using Bio-Layer Interferometry, typically using OCTET® technology (Octet QKe system, ForteBio). Alternatively or in addition, a KinExA® (Kinetic Exclusion Assay) assay, available from Sapidyne Instruments (Boise, Id.) can also be used.

[62] The term "therapeutically effective amount" means an amount of an anti-TFPI antibody or a fragment thereof, or a combination comprising such antibody or fragment thereof, that is of sufficient quantity to achieve the intended purpose, such as an increase in coagulation, or in the case of hemophilia, a decrease in clotting time, or otherwise causing a measurable benefit in vivo to a subject in need. The precise amount will depend upon numerous factors, including, but not limited to the components and physical characteristics of the therapeutic composition, intended patient population, individual patient considerations, and the like, and can be determined by one skilled in the art.

[63] By the term "synergistic therapeutic effective amount," is meant an amount of an anti-TFPI antibody or an antigen-binding fragment thereof that when provided with a second therapeutic agent, e.g., factor Vila (FVIIa), provides a measureable benefit (e.g., decreased clotting time, decreased bleeding time, increased fibrin generation, enhanced platelet accumulation, and the like) that is greater than the additive measurable effect of each therapeutic agent or antibody administered alone.

[64] The term "treatment" includes prophylactic and / or therapeutic treatments. If it is administered prior to clinical manifestation of a condition, the treatment is considered prophylactic. Therapeutic treatment includes, e.g., ameliorating or reducing the severity of a disease, or shortening the length of the disease.

[65] The term "about", as used here, refers to + / - 10% of a value.3. ANTI-TFPI ANTIBODIES

[66] Disclosed and exemplified herein are antibodies (and antigen-binding fragments thereof) that bind to the Tissue Factor Pathway Inhibitor (TFPI). The antibodies and antibody fragments bind to unique epitopes of TFPI. In certain embodiments, the recognition of certain epitope residues in TFPI allows the antibodies (and antigen-binding fragments thereof) to reduce the activity of TFPI. Further, in certain embodiments, antibodies (and antigen-binding fragments thereof) disclosed herein have demonstrated desirable pharmacological activities and pharmacokinetic properties for treatment of coagulation deficiencies and reducing bleeding time.A. Tissue Factor Pathway Inhibitor (TFPI)

[67] TFPI is a multi-valent Kunitz domain containing protease inhibitor. Exemplary sequences of human, mouse, cynomolgus monkey, rabbit, and rat TFPI are provided in Table 2.

[68] Human TFPI is an extracellular glycoprotein with two predominant forms, TFPI-alpha and TFPI-beta. TFPI alpha, which is a 276 amino acid glycosylated protein (MW 43kD) is the largest form of TFPI and consists of three Kunitz like domains and a basic carboxy terminal region.Alternative splicing produces TFPI-beta, which contains Kunitz Domain 1 (K1) and Kunitz Domain 2 (K2), but contains an alternative C-terminal portion lacking Kunitz domain 3 (K3) and the basic region. TFPI-beta is anchored to cell membranes through post-translational modification with a glycosylphosphatidylinositol (GPI) anchor.

[69] The primary targets of TFPI are the proteases Factor Xa (FXa) and Factor Vila (FVIIa), which are key factors in the initiation stage of the coagulation cascade. Biochemical analysis has revealed that K2 is the inhibitor of FXa, while K1 inhibits FVIIa-Tissue Factor complex. The role of K3 is unclear as it does not seem to have direct protease inhibitory activity, but may serve as a recognition site for the co-factor Protein S. The C-terminal domain, unique to TFPI-alpha, may be involved in the recognition of prothrombinase on the platelet surface.

[70] Kunitz domain 1 (K1) corresponds to amino acid residues 26-76 of SEQ ID NO: 2, and Kunitz domain 2 (K2) corresponds to residues 91 to 147 of SEQ ID NO: 2. The K1 and K2 domains from other TFPI homologs, isoforms, variants, or fragments can be identified by sequence alignment or structural alignment against SEQ ID NO: 2.

[71] The TFPI of the instant disclosure includes any naturally occurring form of TFPI which may be derived from any suitable organism. For example, TFPI may be a mammalian TFPI, such as human, mouse, rat, non-human primate, bovine, ovine, canine, feline, or porcine TFPI. In certain embodiments, the TFPI is human TFPI. The TFPI may be a mature form of TFPI (i.e., a TFPI protein that has undergone post-translational processing within a suitable cell). Such a mature TFPI protein may, for example, be glycosylated.

[72] The TFPI of the instant disclosure includes any functional fragments or variants derived from a naturally occurring TFPI. A functional fragment of TFPI can be any part or portion of TFPI that retains the activity of a TFPI, such as the ability to inhibit Factor Xa (FXa), to inhibit the activity of FVI la-tissue factor complex, and / or to function as a negative regulator of coagulation or hemostasis. For example, a functional fragment may comprise a Kunitz domain, such as the K1 domain, K2 domain, or both K1 and K2 domains of TFPI.

[73] A functional variant can comprise one or more mutations as compared to a naturally occurring TFPI, and still retain the activity of a naturally occurring TFPI, such as the ability to inhibit Factor Xa (FXa), or the ability to inhibit the activity of FVIIa-tissue factor complex. For example, a variant may have various degrees of sequence identity to SEQ ID NOs: 1 , 2, 3, 4, 5, 6, or 7, such as at least 60%, 70%, 80%, 85%, 90%, 91 %, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the sequence recited in SEQ ID NO: 1 , SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, or SEQ ID NO: 7.

[74] The TPFI fragments, variants, isoforms and homologs of the invention should maintain important epitope residues (such as Ile105, Arg107, and Leu131 , if TFPI-23 and TFPI-24 antibodies are used) as described herein. In addition, the TFPI may comprise five or more, eight or more, ten or more, twelve or more or fifteen or more surface accessible residues of the K2 domain of TFPI. A surface accessible residue is a residue having more than 40% relative accessibility.

[75] For example, for the K2 domain of TFPI (see, e.g., SEQ ID NO: 2), the following amino acid residues have a greater than 40% relative accessibility: 94-95, 98, 100-110, 1 18-121 , 123-124, 131 , 134, 138-142 and 144-145. The TFPI may comprise five or more, eight or more, ten or more, twelve or more or fifteen or more of these residues, such as a fragment of TFPI that includes five or more, eight or more, ten or more, twelve or more or fifteen or more of these residues.B. Anti-TFPI Antibodies

[76] The antibody or antigen-binding fragment thereof of the invention specifically binds the PC- domain of TFPI, and can inhibit its interaction with FXa and / or reduce the activities of TFPI.TFPI-23 and variants

[77] In one aspect, the invention includes antibody TFPI-23, and variants of TFPI-23 that were made to increase the content of human framework germline residues ("germlining"). For example, TFPI-106 comprises H1 Q to E and H5V to L mutations (Kabat numbering) and TFPI-107 comprises H1 Q to E, H5V to L and H94I to K mutations (Kabat numbering). For purposes of this invention, TFPI-23 parental antibody and TFPI-106 germline variant are interchangeable in their epitope residue and paratope residue interactions.

[78] In one aspect, the invention provides an isolated antibody, or antigen-binding fragment thereof, that specifically binds to an epitope in Kunitz Domain 2 (K2) of Tissue Factor Pathway Inhibitor (TFPI), wherein said epitope comprises residues Ile105, Arg107, and Leu131 , according to the numbering of SEQ ID NO: 2. In certain embodiments, the antibody or antigen-binding fragment thereof does not bind to Kunitz Domain 1 (K1) of TFPI.

[79] As disclosed and exemplified herein, based on the co-crystal structure and computational alanine scan, unique epitopes in the K2 domain of TFPI have been discovered. In particular, the crystal structure shows that the K2 domain of TFPI adopts a cone-shaped structure, with the tip of the cone (especially Arg107) binding to FXa. TFPI-23, TFPI-24, and their variants all recognize residues near the tip of this cone-shaped region, and block the binding of TFPI to FXa. Therefore, antibodies recognizing epitope residues located near the tip of the cone are particularly useful for inhibiting TFPI activities.

[80] In certain embodiments, the invention discloses TFPI epitopes that comprise three residues that are important for antibody-antigen interaction: Ile105, Arg107, and Leu131 (according to the numbering of human TFPI, as shown in SEQ ID NO: 2). Mutating these three residues to Alanine results in loss of binding by TFPI-23, TFPI-24, and their variants. See Table 28, which summarizes the alanine scan results.

[81] Additional TPFI residues have also been identified as involved in antibody binding, but these residues can be mutated to Alanine without a significant destabilizing effect. See Table 28.Accordingly, in certain embodiments, the TFPI epitopes further comprise one or more residues selected from the group consisting of: Cys106, Gly108, Cys130, , Gly132 (according to the numbering of SEQ ID NO: 2), and any combination thereof. These epitope residues are recognized by TFPI-23, TFPI-24, and their variants. See Table 27, which shows the common epitopes residues shared by TFPI-23 and TFPI-24.

[82] In certain embodiments, the epitope further comprises one or more residues selected from the group consisting of: Asp102, Arg1 12, Tyr127, Gly129, Met134, Glu138 (according to the numbering of SEQ ID NO: 2), and any combination thereof. These epitopes residues are recognized by TFPI-23 and its variants (e.g., TFPI-106, TFPI-107), but not by TFPI-24 (and its variants). See Table 27.

[83] In certain embodiments, the epitope does not comprise one or more residues selected from the group consisting of: E100, E101 , P103, Y109, T1 1 1 , Y1 13, F1 14, N1 16, Q1 18, Q121 , C122, E123, R124, F125, K126, L140 (numbering according to SEQ ID NO: 2), and any combination thereof. See, Table 27. According to WO201007269 (Novo Nordisk), reference antibody 4F36 recognizes an epitope comprising E100, E101 , P103, Y109, T1 1 1 , Y1 13, F114, N1 16, Q1 18, Q121 , C122, E123, R124, F125, K126, and L140.

[84] In certain embodiments, the epitope does not comprise one or more residues selected from the group consisting of: D31 , D32, P34, C35, K36, E100, E101 , P103, Y109, K126, G128(numbering according to SEQ ID NO: 2), and any combination thereof. See, Table 27. According to Table 27, reference antibodies 2A8 and 2A8-200 recognize an epitope comprising D31 , D32, P34, C35, K36, E100, E101 , P103, Y109, K126, and G128.

[85] In certain embodiments, the epitope may refer to one or more TFPI "contact" residues (having a heavy atom (i.e., a non-hydrogen atom) that is within a distance of 4 A from a heavy atom of the cognate antibody), and comprises one or more residues selected from the group consisting of: Asp102, Gly104, Ile105, Cys106, Arg107, Gly108, Arg1 12, Tyr127, Gly129, Cys130, Leu131 , Gly132, Met134, Glu138 (according to the numbering of SEQ ID NO: 2), and any combination thereof. See, Table 29B.

[86] In certain embodiments, the epitope may refer to one or more TFPI residues participating in a hydrogen bond with a residue of the antibody, or with a water molecule that is also hydrogen bonded to the cognate antibody (water-mediated hydrogen bonding), and comprises one or more residues selected from the group consisting of: Asp102, Arg107, Arg 1 12, Tyr127, and Leu131 (according to the numbering of SEQ ID NO: 2), and any combination thereof. These epitope residues participate in a hydrogen bond with the cognate antibody. See, Table 29B.

[87] In certain embodiments, the epitope may refer to residues having a non-zero change in buried surface area (BSA) due to interaction with the cognate antibody, and comprises one or more residues selected from the group consisting of: Asp102, Gly104, Ile105, Cys106, Arg107, Gly108, Arg1 12, Tyr127, Gly129, Cys130, Leu131 , Gly132, Asn133, Met134, Glu138 (according to the numbering of SEQ ID NO: 2), and any combination thereof. These. See, Table 29B.

[88] Any combination of these different categories of epitope residues are also encompassed by the invention.

[89] In certain embodiments, the epitope comprises at least 1 , at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 1 1 , at least 12, at least 13, or all of epitope residues described above, or any combination of the various categories of epitope residues described above.

[90] Paratope residues of TFPI-23 (and variants) may refer to contact residues (within 4A of a TFPI epitope residue) as follows: H33 Ala, H47 Trp, H50 Ala, H51 lie, H52 Ser, H56 Ser, H58 Tyr, H95 Leu, H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu, H100A Ser, L29 Ala, L31 Tyr, L91 Tyr, L95A Ser, L95B Gly, and L95C Ser; and optionally L93 Ser and L96 Gly (numbering according to Kabat). L93 Ser (4.07 A) and L96 Gly (4.03 A) are optional because the distances marginally exceed 4A, but are close enough to be rounded to 4A.

[91] Note that the above contact residues are original residues from TFPI-23 antibody. However, based on the structural analysis and alanine scanning, it is believed that a number of contact residues in TFPI-23 can be substituted with another residue without significantly affect antigen- binding. For example, Table 29A shows that a number of contact residues in TFPI-23 can be substituted with other residues and only results in <0.5 kcal / mol effect on binding or stability ("<0.5 kcal / mol" means that a substitution has a neutral effect on binding). In particular, as shown in Table 29A, column 4, three CDR positions and 1 framework position: H47, H58, L91 , and L96 (numbering according to Kabat) only tolerate one or two residues: (a) H47 is Trp or Tyr; (b) H58 is Tyr; (c) L91 is Tyr or Arg; and (d) L96 is Gly or Asn. Other CDR positions can accommodated moresubstitutions as summarized in Table 29A, column 4.

[92] Accordingly, in certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises the following residues (numbering according to Kabat):(a) H33 is Ala, Asn, Gly, His, Lys, Met, Phe, Pro, Ser, Thr, Trp, or Val;(b) H47 is Trp or Tyr;(c) H50 is Ala, Arg, Gly, Lys, Met, Phe, Pro, Ser, Thr, Tyr, or Val;(d) H51 is lie, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val;(e) H52 is Ser, Ala, Arg, Asn, Asp, Gin, Glu, Gly His, lie, Leu, Lys, Met, Phe, Pro, Ser, Trp, Tyr, or Val;(f) H56 is Ser, Arg, Gly, His, lie, Leu, Lys, Met, Phe, Pro, Ser, Thr, Trp, Tyr, or Val;(g) H58 is Tyr; (h) H95 is Leu, Gin, lie, Phe, or Tyr;(i) H96 is Gly, Ala, Arg, Asn Asp, Gin, lie, Lys, Met, Phe, Pro, Ser, Thr, or Val;(j) H97 is Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val;(k) H98 is Thr, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val;(I) H99 is Ser, Ala, Gly, Phe, or Pro;(m) H100 is Leu, Arg, His, lie, Leu, Lys, Phe, Pro, Trp, Tyr, or Val;(n) H100A is Ser, Ala, Arg, Asn Asp, Gin, Glu, His, Leu, Lys, Met, Phe Pro, Ser, Thr, or Trp; (o) L29 is Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val;(p) L31 is Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val;(q) L91 is Tyr or Arg;(r) L95A is Ser, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val;(s) L95B is Ser, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; and(t) L95C is Ser, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys, Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val;and optionally comprises (u) L93 is Tyr, Ala, Arg, Asn Asp, Gin, Glu, Gly, His, Leu, Lys,Met, Phe Pro, Ser, Thr, Trp, Tyr, or Val; and(v) L96 is Gly or Asn.Among these residues, H47 is a framework residue; all others are CDR residues.

[93] When a more stringent substitution criterion is imposed - substitution must result in <-0.5 kcal / mol affinity, meaning that the substitution must have a positive (neutral / stabilizing) effect - contact residues are as follows (numbering according to Kabat) (Table 29A, col. 5):(a) H33 is Ala or Val;(b) H47 is Trp;(c) H50 is Ala;(d) H51 is lie;(e) H52 is Ser, Arg, Lys, Phe, or Tyr;(f) H56 is Ser, Arg, or Lys; (g) H58 is Tyr;(h) H95 is Leu;(i) H96 is Gly, Ala, Arg, Asn, Lys, Pro, Ser, or Val;(j) H97 is Ala;(k) H98 is Thr, His, lie, Leu, Met, Phe, or Tyr;(I) H99 is Ser;(m) H100 is Leu, Phe, Trp, or Tyr;(n) H100A is Ser, Arg, Asn, Gin, Glu His, Leu, Lys, Met, Phe, Pro, or Trp;(0) L29 is Ala;(p) L31 is Tyr;(q) L91 is Tyr;(r) L95A is Ser, Phe, Trp, or Tyr;(s) L95B is Gly; and(t) L95C is Ser, Arg, Asn, Gin, Glu, lie, Leu, Lys, Met, Phe, Trp, Tyr, or Val;and optionally: (u) L93 is Ser; and(v) L96 is Gly.

[94] Alternatively or in addition, the selection of acceptable substitutions can be based on column 6 of Table 29A, where top 3 residues are selected based on their impact on affinity (i.e., top 3 predicted sites with the most stabilizing effect on affinity). Under this criteria, contact residues are as follows (numbering according to Kabat):(a) H33 is Ala, Val, His, or Phe;(b) H47 is Trp or Tyr;(c) H50 is Ala, Thr, Ser, or Phe;(d) H51 is lie, Arg, Lys, or Pro;(e) H52 is Ser, Phe, Arg, or Tyr;(f) H56 is Ser, Lys, Tyr, or Phe;(g) H58 is Tyr;(h) H95 is Leu, lie, Gin, or Phe;(1) H96 is Gly, Arg, Asn, or Lys;(j) H97 is Ala, Leu, Tyr, or lie;(k) H98 is Thr, Tyr, Phe, or His;(I) H99 is Ser, Pro, Ala, or Phe;(m) H 100 is Leu, Tyr, Trp, or Phe; (n) H100A is Ser, Arg, Leu, or Trp;(o) L29 is Ala, Glu, Asp, or Gin;(p) L31 is Tyr, Glu, Asp, or Trp;(q) L91 is Ty or Arg;(r) L95A is Ser, Phe, Tyr, or His;(s) L95B is Gly, Glu, Asp, or Pro; and(t) L95C is Ser, Trp, Tyr, or Phe;and optionally: (u) L93 is Ser, Glu, Asp, or His;(v) L96 is Gly or Asn.

[95] Paratope residues of TFPI-23 (and variants) may also refer to residues participating in a hydrogen bond with a residue of TFPI, or with a water molecule that is also hydrogen bonded to TFPI, and include the following: H58 Tyr, H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu, L29 Ala, L31 Tyr, and L95B Gl (numbering according to Kabat). See, Table 29B.

[96] Paratope residues of TFPI-23 (and variants) may also refer to residues having a non-zero change in BSA due to interaction with TFPI, and include the following (numbering according to Kabat): H33 Ala, H58 Tyr, H95 Leu, H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu, H100A Ser, L29 Ala, L31 Tyr, L91 Tyr, L93 Ser, L95A Ser, and L95B Gly. A cutoff (BSA of 20 A2 or greater, or involved in electrostatic interaction) is applied to avoid inclusion of residues that have minimal interactions. See Table 29B.

[97] If no cutoff of BSA is applied, paratope residues include the following: H33 Ala, H34 Met, H47 Trp, H50 Ala, H51 lie, H52 Ser, H56 Ser, H58 Tyr; H95 Leu, H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu, H100A Ser, L28 Gly, L29 Ala, L31 Tyr, L91 Tyr, L93 Ser, L94 Ser, L95A Ser, L95B Gly, L95C Ser, and L96 Gly. See Table 29C.

[98] An antibody or antigen-binding fragment thereof of the invention may bind to the same epitope or domain of TFPI as the antibodies that are specifically exemplified herein. For example, an antibody or antigen-binding fragment thereof may be identified by comparing their binding to TFPI with that of TFPI-23 or germlined variants (e.g., TFPI-106 and TFPI-107); or by comparing the function of these antibodies with TFPI-23 and its variants. Analyses and assays that may be used for the purpose of such identification include assays assessing the competitions for binding of TFPI and are exemplified in the Examples.

[99] In one embodiment, an antibody or antigen-binding fragment thereof of the invention may bind to the same epitope or region as the antibodies described herein, such as TFPI-23 and its variants. This may include it being in contact with a particular TFPI residue as described above. For example, an antibody or antigen-binding fragment of the invention may bind to TFPI in such a way that it is in contact (within 4A) with a residue selected from the group consisting of: Asp102, Gly104, Ile105, Cys106, Arg107, Gly108, Arg1 12, Tyr127, Gly129, Cys130, Leu131 , Gly132, Met134, Glu138 (according to the numbering of SEQ ID NO: 2), and any combination thereof. An antibody or antigen-binding fragment of the invention may be capable of binding an epitope comprising one or more residues selected from the group consisting of Asp102, Gly104, Ile105, Cys106, Arg107, Gly108, Arg1 12, Tyr127, Gly129, Cys130, Leu131 , Gly132, Met134, Glu138 (according to the numbering of SEQ ID NO: 2), and any combination thereof.

[100] An antibody antigen-binding fragment thereof can comprise at least one paratope residue (numbering according to Kabat) which is within 4.0A of at least one epitope residue on TFPI (numbering according to SEQ ID NO:2), as follows: epitope residue 102 Asp is within 4.0 A of paratope residue H58 Tyr; epitope residue 104 Gly is within 4.0 A of paratope residue H58 Tyr; epitope residue 105 lie is within 4.0 A of paratope residues H33 Ala, H50 Ala, H51 lie, H52 Ser, H56 Ser, H58 Tyr, H95 Leu; epitope residue 106 Cys is within 4.0 A of paratope residues H100 Leu, H100A Ser; epitope residue 107 Arg is within 4.0 A of paratope residue H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu; epitope residue 108 Gly is within 4.0 A of paratope residue H100 Leu; epitope residue 1 12 Arg is within 4.0 A of paratope residue L29 Ala, L31 Tyr; epitope residue 127 Tyr is within 4.0 A of paratope residue L31 Tyr; epitope residue 129 Gly is within 4.0 A of paratope residue L31 Tyr; epitope residue 130 Cys is within 4.0 A of paratope residue L91 Tyr, L95B Gly; epitope residue 131 Leu is within 4.0 A of paratope residue H47 Trp, H50 Ala, H58 Tyr, L95A Ser, L95B Gly, L95C Ser; epitope residue 132 Gly is within 4.0 A of paratope residue H58 Tyr, L95A Ser; H58 Tyr, L95A Ser; epitope residue 134 Met is within 4.0 A of paratope residue L95A Ser; and epitope residue 138 Glu is within 4.0 A of paratope residue L29 Ala. See Tables 29A and 29B

[101] An antibody or an antigen-binding fragment thereof can also comprise at least one paratope residue (numbering according to Kabat) which can form a hydrogen bond with an epitope residue of TFIP (numbering according to SEQ ID NO:2) as follows: epitope residue 102 Asp can form a hydrogen bond with paratope residue H58 Tyr; epitope residue 107 Arg can form a hydrogen bond with at least one paratope residue selected from the group consisting of H96 Gly, H97 Ala, H98 Thr, H99 Ser, and H100 Leu; epitope residue 1 12 Arg can form a hydrogen bond with paratope residue L29 Ala; epitope residue 127 Tyr can form a hydrogen bond with paratope residue L31 Tyr; and epitope residue 131 Leu can form a hydrogen bond with paratope residue L95B Gly. See Table 29B.

[102] An antibody or an antigen-binding fragment thereof can also comprise at least one paratope residue (numbering according to Kabat) having a non-zero change in BSA due to interaction with an epitope residue (numbering according to SEQ ID NO:2) as follows: epitope residue 102 Asp interacts with paratope residue H58 Tyr; epitope residue 104 Gly interacts with paratope residue H58 Tyr; epitope residue 105 lie interacts with at least one paratope residue selected from the group consisting of H33 Ala, H34 Met, H50 Ala, H51 lie, H52 Ser, H56 Ser, H58 Tyr, and H95 Leu; epitope residue 106 Cys interacts with at least one paratope residue selected from the group consisting of H95 Leu, H100 Leu, H100A Ser, and L91 Tyr; epitope residue 107 Arg interacts with at least one paratope residue selected from the group consisting of H96 Gly, H97 Ala, H98 Thr, H99 Ser, and H100 Leu; epitope residue 108 Gly interacts with paratope residue H100 Leu;epitope residue 112 Arg interacts with at least one paratope residue selected from the group consisting of L29 Ala, L31 Tyr, and L93 Ser; epitope residue 127 Tyr interacts with at least one paratope residue selected from the group consisting of L31 Tyr, and L95B Gly; epitope residue 129 Gly interacts with at least one paratope residue selected from the group consisting of H100A Ser, L31 Tyr, and L91 Tyr; epitope residue 130 Cys interacts with at least one paratope residue selected from the group consisting of H95 Leu, H100A Ser, L31 Tyr, L91 Tyr, and L95B Gly;epitope residue 131 Leu interacts with at least one paratope residue selected from the group consisting of H47 Trp, H50 Ala, H58 Tyr, H95 Leu, L31 Tyr, L91 Tyr, L95A Ser, L95B Gly, L95C Ser, and L96 Gly; epitope residue 132 Gly interacts with at least one paratope residue selected from the group consisting of H58 Tyr, and L95A Ser; epitope residue 133 Asn interacts with paratope residue L95A Ser; epitope residue 134 Met interacts with at least one paratope residue selected from the group consisting of L93 Ser, L94 Ser, and L95A Ser; and epitope residue 138 Glu interacts with at least one paratope residue selected from the group consisting of L28 Gly, L29 Ala, and L93 Ser.

[103] An antibody or an antigen-binding fragment thereof of the invention can be any antibody or antigen-binding fragment that comprises any of the paratope residues above which interacts with at least one epitope residue listed above.

[104] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises at least 1 , at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 11 , at least 12, at least 13, or all of paratope residues described above, or any combination of the various categories of paratope residues described above. Further, conservative substitutions may be introduced to these paratope residues. For example, the antibody or antigen binding fragment thereof may comprise 1 , 2, 3, 4, 5, 6, 7, or 8 conservative substitutions according to Table 34.Table 34 Conservative Substitutions

[105] An antibody of the invention may have the ability to compete with another antibody for binding to TFPI as described herein. For example, an antibody of the invention may cross-compete with TFPI-23 and its variants thereof described herein for binding to TFPI, or to a suitable fragment or variant of TFPI that is bound by the TFPI-23 antibodies. Such cross-competing antibodies can be identified based on their ability to cross-compete with an exemplified antibody of the invention in standard binding assays. For example, SPR (e.g., by using a Biacore™ system), ELISA assays or flow cytometry may be used to demonstrate cross-competition. Such cross-competition may suggest that the two antibodies bind to identical, overlapping or similar epitopes.

[106] An antibody of the invention may therefore be identified by a method that comprises a binding assay which assesses whether or not a test antibody is able to compete with an exemplified antibody of the invention (such as TFPI-23, or any variant or fragment thereof as described herein) for a binding site on the target molecule.

[107] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises the following heavy chain CDR sequences: (i) CDR-H1 comprising SEQ ID NO: 38, CDR-H2 comprising SEQ ID NO: 39, and CDR-H3 comprising SEQ ID NO: 40; and / or (ii) the following light chain CDR sequences: CDR-L1 comprising SEQ ID NO: 33, CDR-L2 comprising SEQ ID NO: 34, and CDR-L3 comprising SEQ ID NO: 35. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises following heavy chain CDR sequences: (i) a CDR-H1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 38, a CDR-H2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 39, and a CDR-H3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 40; and / or (ii) the following light chain CDR sequences: a CDR-L1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 33, a CDR-L2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 34, and a CDR-L3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 35. In certain embodiments, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 3, no more than 2, or no more than one substitution is made in each CDR, relative to SEQ ID NOs. 38, 39, 40, 33, 34, and 35, respectively. In certain embodiments, the substitution is a conservative substation according to Table 34. In certain embodiments, the substitution is according to Table 29A, column 4, column 5, or column 6.

[108] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises a human framework sequence. For example, heavy chain framework sequence can be from a human VH3 germline, a VH1 germline, a VH5 germline, or a VH4 germline. Preferred human germline heavy chain frameworks are frameworks derived from VH1 , VH3, or VH5 germlines. For example, VH frameworks from the following germlines may be used: IGHV3-23, IGHV3-7, or IGHV1-69 (germline names are based on IMGT germline definition). Preferred human germline light chain frameworks are frameworks derived from VK or νλ germlines. For example, VL frameworks from the following germlines may be used: IGKV1-39 or IGKV3-20 (germline names are based on IMGT germline definition). Alternatively or in addition, the framework sequence may be a human germline consensus framework sequence, such as the framework of human VX1 consensus sequence, VK1 consensus sequence, VK2 consensus sequence, VK3 consensus sequence, VH3 germline consensus sequence, VH1 germline consensus sequence, VH5 germline consensus sequence, or VH4 germline consensus sequence.

[109] Sequences of human germline frameworks are available from various public databases, such as V-base, IMGT, NCBI, or Abysis.[1 10] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises: (i) a VH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 41 , 63, and 65; and / or (ii) a VL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO:36. Any combination of these VL and VH sequences is also encompassed by the invention. [1 11] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises: (i) a CH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 20; and / or (ii) a CL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 26. Any combination of these CH and CL sequences is also encompassed by the invention.[1 12] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises an Fc domain. The Fc domain can be derived from IgA (e.g., \gA-\ or lgA2), IgG, IgE, or IgG (e.g., Igd , lgG2, lgG3, or lgG4).[1 13] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises: (i) a heavy chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 42, SEQ ID NO: 64, or SEQ ID NO: 66; and / or (ii) a light chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 37. Any combination of these heavy chain and light chain sequences is also encompassed by the invention.TFPI-24 and variants[1 14] The co-crystal structures show that TFPI-24 (and its variants) share a number of epitope residues with TFPI-23. Among these, Ile105, Arg107, and Leu131 (according to the numbering of human TFPI, as shown in SEQ ID NO: 2) are believed to be important for antibody-antigen interaction. Other shared epitope residues include: Cys106, Gly108, C130, L131 , and G132, (according to the numbering of SEQ ID NO: 2).[1 15] Epitope residues that are specific for TFPI-24 (and its variants) include: Glu100, Glu101 , Asp102, Gly104, and Tyr109. TFPI-23 and its variants do not bind to these residues. See Table 27. Accordingly, the invention provides an isolated antibody, or antigen-binding fragment thereof, that specifically binds to an epitope in K2 of TFPI, wherein said epitope (i) comprises residues Ile105, Arg107, and Leu131 ; (ii) optionally comprises one or more residues selected from the group consisting of: Cys106, Gly108, Cys130, Leu131 , and Gly132; and (iii) further optionally comprises one or more residues selected from the group consisting of: Glu100, Glu101 , Asp102, Gly104, and Tyr109 (according to the numbering of SEQ ID NO: 2).[1 16] In certain embodiments, the epitope does not comprise one or more residues selected from the group consisting of: P103, T1 11 , Y1 13, F1 14, N1 16, Q1 18, Q121 , C122, E123, R124, F125, K126, L140 (numbering according to SEQ ID NO: 2), and any combination thereof. See, Table 27. According to WO201007269 (Novo Nordisk), reference antibody 4F36 recognizes an epitope comprising P103, T11 1 , Y1 13, F1 14, N1 16, Q1 18, Q121 , C122, E123, R124, F125, K126, and L140.[1 17] In certain embodiments, the epitope does not comprise one or more residues selected from the group consisting of: D31 , D32, P34, C35, K36, P103, K126, Y127, G128 (numbering according to SEQ ID NO: 2), and any combination thereof. See, Table 27. According to Table 27, reference antibodies 2A8 and 2A8-200 recognize an epitope comprising D31 , D32, P34, C35, K36, P103, K126, Y127, and G128.[1 18] Paratope residues from TFPI-24 (based on BSA) have also been characterized (see Table 24) and include the following: H33 Ala, H35 Gin, H52 Ser, H53 Asn, H55 Arg, H56 Ser, H95 Phe, H96 Leu, H97 His, H99 Ser, H101 Asp, L31 Met, L32 Tyr, L34 His, L36 Tyr, L50 Arg, L91 Trp, and L96 Tyr. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises at least 8, at least 9, at least 10, at least 1 1 , at least 12, at least 13, at least 14, at least 15, at least 16, at least 17, or all of these paratope residues. Further, conservative substitutions may be introduced to these paratope residues. For example, the antibody or antigen binding fragment thereof may comprise 1 , 2, 3, 4, 5, 6, 7, or 8 conservative substitutions according to Table 34.[1 19] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises the following heavy chain CDR sequences: (i) CDR-H1 comprising SEQ ID NO: 48, CDR-H2 comprising SEQ ID NO: 49, and CDR-H3 comprising SEQ ID NO: 50; and / or (ii) the following light chain CDR sequences: CDR-L1 comprising SEQ ID NO: 43, CDR-L2 comprising SEQ ID NO: 44, and CDR-L3 comprising SEQ ID NO: 45. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises following heavy chain CDR sequences: (i) a CDR-H1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 48, a CDR-H2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 49, and a CDR-H3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 50; and / or (ii) the following light chain CDR sequences: a CDR-L1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 43, a CDR-L2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 44, and a CDR-L3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 45. In certain embodiments, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 3, no more than 2, or no more than one substitution is made in each CDR, relative to SEQ ID NOs. 48, 49, 50, 43, 44, and 45, respectively. In certain embodiments, the substitution is a conservative substation according to Table 34.

[120] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises a human framework sequence. For example, heavy chain framework sequence can be from a human VH3 germline, a VH1 germline, a VH5 germline, or a VH4 germline, as described above. Preferred human germline light chain frameworks are frameworks derived from VK or νλ germlines, as described above. Consensus human germline framework sequences may also be used as described above.

[121] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a VH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 67, 69, 51 , and 79; and / or (ii) a VL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 46, 71 , 73, 75, and 77. Any combination of these VL and VH sequences is also encompassed by the invention.

[122] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises: (i) a CH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 20; and / or (ii) a CL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 26. Any combination of these CH and CL sequences is also encompassed by the invention.

[123] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises an Fc domain. The Fc domain can be derived from IgA (e.g., IgAi or lgA2), IgG, IgE, or IgG (e.g., IgG^ lgG2, lgG3, or lgG4).

[124] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises: (i) a heavy chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 52, SEQ ID NO: 68, SEQ ID NO: 70, or SEQ ID NO: 80; and / or (ii) a light chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 47, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 76, or SEQ ID NO: 78. Any combination of these heavy chain and light chain sequences is also encompassed by the invention.4D8 and variants

[125] Co-crystal structures also reveal the epitope and paratope information for antibody 4D8 and variants. Epitope residues for 4D8 and its variants include: Glu101 , Pro103, Tyr109, Thr1 1 1 , Ser1 19, Gln121 , Glu123, Arg124, Lys126, and Leu140, according to the numbering of SEQ ID NO: 2.

[126] In certain embodiments, the epitope does not comprise one or more residues selected from the group consisting of: E100, D102, R107, Y1 13, F114, N1 16, Q118, C122 (numbering according to SEQ ID NO: 2), and any combination thereof. See, Table 27. According to WO201007269 (Novo Nordisk), reference antibody 4F36 recognizes an epitope comprising E100, D102, R107, Y1 13, F1 14, N1 16, Q1 18, and C122.

[127] In certain embodiments, the epitope does not comprise one or more residues selected from the group consisting of: D31 , D32, P34, C35, K36, E100, 1105, R107, G108, Y127, G128(numbering according to SEQ ID NO: 2), and any combination thereof. See, Table 27. According to Table 27, reference antibodies 2A8 and 2A8-200 recognize an epitope comprising D31 , D32, P34, C35, K36, E100, 1105, R107, G108, Y127, and G128.

[128] Paratope residues from 4D8 (based on BSA) have also been characterized (see Table 20) and include the following:: H50 Asp, H57 Thr, H58 Leu, H59 Tyr, H61 Gin, H98 Asp, H99 Tyr, H100 Asp, L30 His, L50 Trp, L92 Tyr, L93 Thr, L94 Thr, and L96 Tyr. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises at least 8, at least 9, at least 10, at least 11 , at least 12, at least 13, or all of these paratope residues. Further, conservative substitutions may be introduced to these paratope residues. For example, the antibody or antigen binding fragment thereof may comprise 1 , 2, 3, 4, 5, 6, 7, or 8 conservative substitutions according to Table 34.

[129] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises the following heavy chain CDR sequences: (i) CDR-H1 comprising SEQ ID NO: 87, CDR-H2 comprising SEQ ID NO: 88, and CDR-H3 comprising SEQ ID NO: 89; and / or (ii) the following light chain CDR sequences: CDR-L1 comprising SEQ ID NO: 81 , CDR-L2 comprising SEQ ID NO: 82, and CDR-L3 comprising SEQ ID NO: 83. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises following heavy chain CDR sequences: (i) a CDR-H1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 87, a CDR-H2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 88, and a CDR-H3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 89; and / or (ii) the following light chain CDR sequences: a CDR-L1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 81 , a CDR-L2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 82, and a CDR-L3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 83. In certain embodiments, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 3, no more than 2, or no more than one substitution is made in each CDR, relative to SEQ ID NOs. 87, 88, 89, 81 , 82, and 83, respectively. In certain embodiments, the substitution is a conservative substation according to Table 34.

[130] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises a human framework sequence. For example, heavy chain framework sequence can be from a human VH3 germline, a VH1 germline, a VH5 germline, or a VH4 germline, as described above. Preferred human germline light chain frameworks are frameworks derived from VK or \ / λ germlines, as described above. Consensus human germline framework sequences may also be used as described above.

[131] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a VH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 90, 95, 97, 99, 101 , 103, 105, and 107; and / or (ii) a VL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs: 84, 109, and 1 11. Any combination of these VL and VH sequences is also encompassed by the invention.

[132] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a CH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 20, and / or (ii) a CL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 91 or SEQ ID NO: 85. Any combination of these CH and CL sequences is also encompassed by the invention.

[133] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises an Fc domain. The Fc domain can be derived from IgA (e.g., IgAi or lgA2), IgG, IgE, or IgG (e.g., Igd , lgG2, lgG3, or lgG4).

[134] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a heavy chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 92, SEQ ID NO: 94, SEQ ID NO: 96, SEQ ID NO: 98, SEQ ID NO: 100, SEQ ID NO: 102, SEQ ID NO: 104, SEQ ID NO: 106, SEQ ID NO: 108; and / or (ii) a light chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 86, SEQ ID NO: 93, SEQ ID NO: 1 10, or SEQ ID NO: 1 12. Any combination of these heavy chain and light chain sequences is also encompassed by the invention.TFPI-3 and variants

[135] Also provided herein are TFPI-3 and its variants. Accordingly, the antibody or antigen-binding fragment thereof based on TFPI-3 comprises the following heavy chain CDR sequences: (i) CDR- H1 comprising SEQ ID NO: 16, CDR-H2 comprising SEQ ID NO: 17, and CDR-H3 comprising SEQ ID NO: 18; and / or (ii) the following light chain CDR sequences: CDR-L1 comprising SEQ ID NO: 10, CDR-L2 comprising SEQ ID NO: 1 1 , and CDR-L3 comprising SEQ ID NO: 12. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises following heavy chain CDR sequences: (i) a CDR-H1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 16, a CDR-H2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 17, and a CDR-H3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 18; and / or (ii) the following light chain CDR sequences: a CDR-L1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 10, a CDR-L2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 1 1 , and a CDR-L3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 12. In certain embodiments, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 3, no more than 2, or no more than one substitution is made in each CDR, relative to SEQ ID NOs. 16, 17, 18, 10, 11 , and 12, respectively. In certain embodiments, the substitution is a conservative substation according to Table 34.

[136] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises a human framework sequence. For example, heavy chain framework sequence can be from a human VH3 germline, a VH1 germline, a VH5 germline, or a VH4 germline, as described above. Preferred human germline light chain frameworks are frameworks derived from VK or νλ germlines, as described above. Consensus human germline framework sequences may also be used as described above.

[137] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a VH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 19, and / or (ii) a VL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 13. Any combination of these VL and VH sequences is also encompassed by the invention.

[138] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a CH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 20; and / or (ii) a CL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 91 or SEQ ID NO: 14. Any combination of these CH and CL sequences is also encompassed by the invention.

[139] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises an Fc domain. The Fc domain can be derived from IgA (e.g., \gA-\ or lgA2), IgG, IgE, or IgG (e.g., IgG, , lgG2, lgG3, or lgG4).

[140] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a heavy chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 21 ; and / or (ii) a light chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 15. Any combination of these heavy chain and light chain sequences is also encompassed by the invention.TFPI-21 and variants

[141] Also provided herein are TFPI-21 and its variants. Accordingly, the antibody or antigen- binding fragment thereof based on TFPI-21 comprises the following heavy chain CDR sequences: (i) CDR-H1 comprising SEQ ID NO: 28, CDR-H2 comprising SEQ ID NO: 29, and CDR-H3 comprising SEQ ID NO: 30; and / or (ii) the following light chain CDR sequences: CDR-L1 comprising SEQ ID NO: 22, CDR-L2 comprising SEQ ID NO: 23, and CDR-L3 comprising SEQ ID NO: 24. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises following heavy chain CDR sequences: (i) a CDR-H1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 28, a CDR-H2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 29, and a CDR-H3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 30; and / or (ii) the following light chain CDR sequences: a CDR-L1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 22, a CDR-L2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 23, and a CDR-L3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 24. In certain embodiments, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 3, no more than 2, or no more than one substitution is made in each CDR, relative to SEQ ID NOs. 28, 29, 30, 22, 23, and 24, respectively. In certain embodiments, the substitution is a conservative substation according to Table 34.

[142] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises a human framework sequence. For example, heavy chain framework sequence can be from a human VH3 germline, a VH 1 germline, a VH5 germline, or a VH4 germline, as described above. Preferred human germline light chain frameworks are frameworks derived from V or νλ germlines, as described above. Consensus human germline framework sequences may also be used as described above.

[143] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a VH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 31 , and / or (ii) a VL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 25. Any combination of these VL and VH sequences is also encompassed by the invention.

[144] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a CH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 20; and / or (ii) a CL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 91 or SEQ ID NO: 26. Any combination of these CH and CL sequences is also encompassed by the invention.

[145] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises an Fc domain. The Fc domain can be derived from IgA (e.g., \gA-\ or lgA2), IgG, IgE, or IgG (e.g., Igd , lgG2, lgG3, or lgG4).

[146] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a heavy chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ I D NO: 32, and / or (ii) a light chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 27. Any combination of these heavy chain and light chain sequences is also encompassed by the invention.TFPI-26 and variants

[147] Also provided herein are TFPI-26 and its variants. Accordingly, the antibody or antigen- binding fragment thereof based on TFPI-26 comprises the following heavy chain CDR sequences: (i) CDR-H1 comprising SEQ ID NO: 58, CDR-H2 comprising SEQ ID NO: 59, and CDR-H3 comprising SEQ ID NO: 60; and / or (ii) the following light chain CDR sequences: CDR-L1 comprising SEQ ID NO: 53, CDR-L2 comprising SEQ ID NO: 54, and CDR-L3 comprising SEQ ID NO: 55. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises following heavy chain CDR sequences: (i) a CDR-H1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 58, a CDR-H2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 59, and a CDR-H3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 60; and / or (ii) the following light chain CDR sequences: a CDR-L1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 53, a CDR-L2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 54, and a CDR-L3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 55. In certain embodiments, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 3, no more than 2, or no more than one substitution is made in each CDR, relative to SEQ ID NOs. 58, 59, 60, 53, 54, and 55, respectively. In certain embodiments, the substitution is a conservative substation according to Table 34.

[148] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises a human framework sequence. For example, heavy chain framework sequence can be from a human VH3 germline, a VH1 germline, a VH5 germline, or a VH4 germline, as described above. Preferred human germline light chain frameworks are frameworks derived from V or \ / λ germlines, as described above. Consensus human germline framework sequences may also be used as described above.

[149] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a VH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 61 , and / or (ii) a VL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 56. Any combination of these VL and VH sequences is also encompassed by the invention.

[150] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a CH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 20; and / or (ii) a CL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 26. Any combination of these CH and CL sequences is also encompassed by the invention.

[151] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises an Fc domain. The Fc domain can be derived from IgA (e.g., \gA-\ or lgA2), IgG, IgE, or IgG (e.g., Igd , lgG2, lgG3, or lgG4).

[152] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a heavy chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 62; and / or (ii) a light chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 57. Any combination of these heavy chain and light chain sequences is also encompassed by the invention.6B7.c5 and variants

[153] Also provided herein are 6B7.c5 and its variants. Accordingly, the antibody or antigen-binding fragment thereof based on 6B7.c5 comprises the following heavy chain CDR sequences: (i) CDR- H1 comprising SEQ ID NO: 118, CDR-H2 comprising SEQ ID NO: 119, and CDR-H3 comprising SEQ ID NO: 120; and / or (ii) the following light chain CDR sequences: CDR-L1 comprising SEQ ID NO: 113, CDR-L2 comprising SEQ ID NO: 1 14, and CDR-L3 comprising SEQ ID NO: 1 15. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises following heavy chain CDR sequences: (i) a CDR-H1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 118, a CDR-H2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 1 19, and a CDR-H3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 120; and / or (ii) the following light chain CDR sequences: a CDR-L1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 1 13, a CDR-L2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 114, and a CDR-L3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 1 15. In certain embodiments, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 3, no more than 2, or no more than one substitution is made in each CDR, relative to SEQ ID NOs. 1 18, 119, 120, 1 13, 1 14, and 1 15, respectively. In certain embodiments, the substitution is aconservative substation according to Table 34.

[154] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises a human framework sequence. For example, heavy chain framework sequence can be from a human VH3 germline, a VH1 germline, a VH5 germline, or a VH4 germline, as described above. Preferred human germline light chain frameworks are frameworks derived from VK or νλ germlines, as described above. Consensus human germline framework sequences may also be used as described above.

[155] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a VH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 121 , and / or (ii) a VL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 116. Any combination of these VL and VH sequences is also encompassed by the invention.

[156] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a CH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 91 , and / or (ii) a CL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 91 or SEQ ID NO: 85. Any combination of these CH and CL sequences is also encompassed by the invention.

[157] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises an Fc domain. The Fc domain can be derived from IgA (e.g., IgAi or lgA2), IgG, IgE, or IgG (e.g., IgG, , lgG2, lgG3, or lgG4).

[158] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a heavy chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 122; and / or (ii) a light chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 1 17. Any combination of these heavy chain and light chain sequences is also encompassed by the invention.7A4.D9 and variants

[159] Also provided herein are TFPI-3 and its variants. Accordingly, the antibody or antigen-binding fragment thereof based on TFPI-3 comprises the following heavy chain CDR sequences: (i) CDR- H1 comprising SEQ ID NO: 128, CDR-H2 comprising SEQ ID NO: 129, and CDR-H3 comprising SEQ ID NO: 130; and / or (ii) the following light chain CDR sequences: CDR-L1 comprising SEQ ID NO: 123, CDR-L2 comprising SEQ ID NO: 124, and CDR-L3 comprising SEQ ID NO: 125. In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises following heavy chain CDR sequences: (i) a CDR-H1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 128, a CDR-H2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 129, and a CDR-H3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 130; and / or (ii) the following light chain CDR sequences: a CDR-L1 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 123, a CDR-L2 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 124, and a CDR-L3 at least 85%, at least 90%, or at least 95% identical to SEQ ID NO: 125. In certain embodiments, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 3, no more than 2, or no more than one substitution is made in each CDR, relative to SEQ ID NOs. 128, 129, 130, 123, 124, and 125, respectively. In certain embodiments, the substitution is aconservative substation according to Table 34.

[160] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises a human framework sequence. For example, heavy chain framework sequence can be from a human VH3 germline, a VH1 germline, a VH5 germline, or a VH4 germline, as described above. Preferred human germline light chain frameworks are frameworks derived from VK or \ / λ germlines, as described above. Consensus human germline framework sequences may also be used as described above.

[161] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a VH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 131 , and / or (ii) a VL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 126 . Any combination of these VL and VH sequences is also encompassed by the invention.

[162] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a CH comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 91 ; and / or (ii) a CL comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 91 or SEQ ID NO: 85. Any combination of these CH and CL sequences is also encompassed by the invention.

[163] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises an Fc domain. The Fc domain can be derived from IgA (e.g., \gA-\ or lgA2), IgG, IgE, or IgG (e.g., Igd , lgG2, lgG3, or lgG4).

[164] In certain embodiments, the antibody or antigen-binding fragment thereof described herein comprises (i) a heavy chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 132; and / or (ii) a light chain comprising an amino acid sequence that is at least 50%, at least 60%, at least 70%, 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% identical to SEQ ID NO: 127. Any combination of these heavy chain and light chain sequences is also encompassed by the invention.

[165] Also disclosed is an antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI , and competes for binding to TFPI with any of the antibody or antigen- binding fragment thereof described herein, such as any one of the antibodies listed in Table 3 (or antigen-binding fragment thereof). For example, if the binding of an antibody, or an antigen-binding portion thereof, to TFPI hinders the subsequent binding to TFPI by TFPI-23 or TFPI-106, the antibody or an antigen-binding portion thereof competes with TFPI-23 or TFPI-106 for TFPI binding.

[166] Also disclosed is an antibody, or antigen-binding fragment thereof, that specifically binds to the K2 Domain of TFPI , and binds to the same TFPI epitope as any of the antibody or antigen- binding fragment thereof described herein, such as any one of the antibodies listed in Table 3 or antigen-binding fragment thereof.

[167] An exemplary antibody competition assay (and overlapping epitope analysis) by SPR is provided in Example 6.

[168] The antibodies and antigen-binding fragments disclosed herein include monoclonal antibodies, polyclonal antibodies, antibody fragments (e.g., Fab, Fab', F(ab')2, Fv, Fc, etc.), chimeric antibodies, bispecific antibodies, heteroconjugate antibodies, single chain (ScFv), mutants thereof, fusion proteins comprising an antibody portion, domain antibodies (dAbs), humanized antibodies, and any other modified configuration of the immunoglobulin molecule that comprises an antigen recognition site of the required specificity, including glycosylation variants of antibodies, amino acid sequence variants of antibodies, and covalently modified antibodies. The antibodies and antigen-binding fragments may be murine, rat, human, or any other origin (including chimeric or humanized antibodies). In some embodiments, the antibody is a monoclonal antibody. In some embodiments, the antibody is a chimeric, humanized or human antibody. In certain embodiments, the antibody is a human antibody. In certain embodiments, the antibody is a humanized antibody.

[169] In certain embodiments, the antibody or antigen-binding fragment thereof disclosed herein has an affinity (Kd) value of no more than about 1x10"3 M, such as no more than about 5x10"4 M, no more than about 4x10"4 M, no more than about 3x10"4 M, no more than about 2x10"4 M, no more than about 1x10"4 M, no more than about 9x10"5 M, no more than about 8x10"5 M, no more than about 7x10"5 M, no more than about 6x10"5 M, no more than about 5x10"5 M, no more than about 4x10"5 M, no more than about 3x10"5 M, no more than about 2x10"5 M, no more than about 1x10"5 M, no more than about 9x10"6 M, no more than about 8x10"6 M, no more than about 7x10"6 M, no more than about 6x10"6 M, no more than about 5x10"6 M, no more than about 4x10"6 M, no more than about 3x10"6 M, no more than about 2x10"6 M, no more than about 1x10"6 M, no more than about 9x10"7 M, no more than about 8x10"7 M, no more than about 7x10"7 M, no more than about 6x10"7 M, no more than about 5x10"7 M, no more than about 4x10"7 M, no more than about 3x10"7 M, no more than about 2x10"7 M, no more than about 1x10"7 M, no more than about 9x10"8 M, no more than about 8x10"8 M, no more than about 7x10"8 M, no more than about 6x10"8 M, no more than about 5x10"8 M, no more than about 4x10"8 M, no more than about 3x10"8 M, no more than about 2x10"8 M, no more than about 1x10"8 M, no more than about 9x10"9 M, no more than about 8x10"9 M, no more than about 7x10"9 M, no more than about 6x10"9 M, no more than about 5x10"9 M, no more than about 4x10"9 M, no more than about 3x10"9 M, no more than about 2x10"9 M, no more than about 1x10"9 M, from about 1 x 10"3 M to about 1 x 10"13 M, 1 x 10"4 M to about 1 x 10"13 M, 1 x 10"5 M to about 1 x 10"13 M, from about 1 x 10"6 M to about 1 x 10"13 M, from about 1 x 10"7 M to about 1 x 10"13 M, from about 1 x 10"8 M to about 1 x 10"13 M, from about 1 x 10"9 M to about 1 x 10"13 M, 1 x 10"3 M to about 1 x 10"12 M, 1 x 10"4 M to about 1 x 10"12 M, from about 1 x 10"5 M to about 1 x 10"12 M, from about 1 x 10"6 M to about 1 x 10"12 M, from about 1 x 10"7 M to about 1 x 10"12 M, from about 1 x 10"8 M to about 1 x 10"12 M, from about 1 x 10"9 M to about 1 x 10"12 M, 1 x 10"3 M to about 1 x 10"11 M, 1 x 10"4 M to about 1 x 10"11 M, from about 1 x 10"5 M to about 1 x 10"11 M, from about 1 x 10"6 M to about 1 x 10"11 M, from about 1 x 10"7 M to about 1 x 10"11 M, from about 1 x 10"8 M to about 1 x 10"11 M, from about 1 x 10"9 M to about 1 x 10"11 M, 1 x 10"3 M to about 1 x 10"10 M, 1 x 10"4 M to about 1 x 10"10 M, from about 1 x 10"5 M to about 1 x 10"10 M, from about 1 x 10"6 M to about 1 x 10"10 M, from about 1 x 10"7 M to about 1 x 10"10 M, from about 1 x 10"8 M to about 1 x 10"10 M, or from about 1 x 10"9 M to about 1 x 10"10 M.

[170] In certain embodiments, the dissociation constant is measured using surface plasmon resonance (SPR) method (Biacore). Surface plasmon resonance refers to an optical phenomenon that allows for the analysis of real-time biospecific interactions by detection of alterations in protein concentrations within a biosensor matrix, for example using the BIACORE™ system. In certain embodiments, the SPR measurement is conducted using a Biacore T100 or T200 instrument.

[171] For example, a standard assay condition for surface plasmon resonance can be based on ligand immobilization of approximately 100 Response Units (RU) of IgG on the SPR chip. Purified target proteins are diluted in buffer to a range of final concentrations and injected at a requisite flow rate (e.g. 10-100 μΙ / min) to allow the calculation of Ka. Dissociation is allowed to proceed to establish off-rate (Kd), followed by a 5 sec pulse of 3M MgCI2 (or 20 mM NaOH) for regeneration of the chip surface. Sensorgrams are then analyzed using a kinetics evaluation software package.

[172] In an exemplary embodiment, the SPR assay is according to the conditions as set forth in Example 1 , under the subheading "Surface plasmon resonance (SPR)."

[173] In certain embodiments, the dissociation constant is measured using solution-based kinetic exclusion assay (KinExA™). In a particular embodiment, the KinExA measurement is conducted using a KinExA™ 3200 instrument (Sapidyne). The Kinetic Exclusion Assay (KinExA™) is a general purpose immunoassay platform (basically a flow spectrofluorimeter) that is capable of measuring equilibrium dissociation constants, and association and dissociation rate constants for antigen / antibody interactions. Since KinExA™ is performed after equilibrium has been obtained it is an advantageous technique to use for measuring the Kd of high affinity interactions where the off- rate of the interaction may be very slow. The KinExA™ methodology can be conducted generally as described in Drake et al (2004) Analytical Biochemistry 328, 35-43.

[174] In general, a TFPI antibody needs to bind to TFPI with high affinity, in order to effectively block the activities of TFPI. However, because TFPI is also expressed on cell surface, when the binding affinity of an antibody is too high, the antibody can quickly get internalized and degraded by a host cell. This could potentially result in a short half-life and repeated injections. For example, antibody TFPI-23 shows a lower binding affinity (Kd) as compared to TFPI-24, and under certain circumstances, is more desirable because it has a lower internalization rate and longer half-life. Accordingly, binding affinities (Kd) from 5x10"7 M to about 5x10"11 M, in particular from about 1x10"8 M to about 1x10"10 M (0.1 nM to 10 nM), are generally desirable if longer half-life is desired. This range is believed to strike a balance between (i) binding affinities that are needed for effectively inhibiting the activities of TFPI, and (ii) a longer half-life and reduced antibody internalization.

[175] In particular, it is believed that to maintain weekly subcutaneous dosing at 3 mg / kg, Kd value from about 1x10"8 M to about 1x10"10 M (0.1 nM to 10 nM) is desired.

[176] Whether an antibody or antigen-binding fragment thereof reduces the activity of TFPI, or reduces the binding of TFPI to a physiological substrate (e.g., FXa) can be determined by measuring the decrease in the binding affinity of TFPI to said physiological substrate, for example by comparing (i) the binding affinity of TFPI to its substrate in the presence of the anti-TFPI antibody (or antigen-binding fragment thereof), with (ii) the binding affinity of TFPI to the same substrate in the absence of the anti-TFPI antibody. The reduction in binding of TFPI to a physiological substrate (e.g., FXa) can be at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99%, in the presence of the anti-TFPI antibody (or antigen- binding fragment thereof). The expected binding of TFPI to its physiological substrate in the absence of the antibody (or fragment) can be set as 100%.

[177] The TFPI inhibitory activities, also referred to herein as "reducing the activity of TFPI," of an anti-TFPI antibody or antigen-binding fragment thereof can also be assessed in an in vivo model and / or in vitro using, e.g., plasmatic systems. For example, inhibitory activities (or the level of reducing an activity of TFPI) of an antibody can be assessed by: (i) a decrease in clotting time as measured in a plasma based dilute prothrombin time assay; (ii) a reduction in clotting time in whole blood as measured by thromboelastrography; (iii) an increase in thrombin generation; (iv) an increase in FXa activity in the presence of TFPI; (v) enhanced platelet accumulation in the presence of TFPI; (vi) increased fibrin generation in the presence of TFPI; or (vii) any combination thereof. The inhibitory activities of an antibody or antigen-binding fragment can be dose-dependent (e.g., causing a dose-dependent decrease in clotting time as measured in a plasma based dilute prothrombin time assay).

[178] Several exemplary assays for assessing the TFPI inhibitory activity of an antibody are described in detail in the Examples. For example, the plasma dilute Prothrombin Time (PT) assay is a modified PT assay using diluted thromboplastin or Tissue Factor to prolong the clotting time and dynamic range of the assay. An inhibitory / neutralizing anti-TFPI antibody should decrease the dilute prothrombin time.

[179] Another exemplary model system for determining TFPI-inhibitory activity is the extrinsic tenase assay, which tests the ability of antibody or antigen-binding fragment thereof to restore extrinsic complex-mediated FX activation in the presence of TFPI. Another model system for characterizing TFPI-inhibitory activity is the FXa inhibition assay, wherein FXa activity is measured in the presence of TFPI (see Sprecher et al., Proc. Nat. Acad. Sci. USA 91 :3353-3357 (1994)).

[180] The inhibitory activities of an antibody or antigen-binding fragment thereof can also be assessed in a plasma-based assay. Thrombin formation can be triggered in plasma substantially lacking FVIII or FIX activity (e.g., the residual coagulation factor activity is lower than 1 %) in the presence of an anti-TFPI antibody or antigen-binding fragment thereof. Thrombin formation can be detected using a fluorogenic or chromogenic substrate. Prothrombin conversion can be measured using, e.g., a Thrombograph™ (Thermo Scientific, Waltham, Mass.), and the resulting data can be compiled into a Calibrated Automatic Thrombogram generated by Thrombinoscope™ software available from Thrombinoscope BV.

[181] For example, an antibody or antigen-binding fragment may improve TFPI-regulated thrombin generation in the absence of FVIII (e.g., in FVIII-depleted plasma) to at least 1 % of the level of TFPI-dependent thrombin generation in normal plasma. Generally, normal (unafflicted) plasma contains about 0.5 U / mL to about 2 U / mL Factor VIII. Accordingly, in some instances, an antibody or antigen-binding fragment of the invention will enhance thrombin formation in the absence of FVIII to at least about 1 % of that observed in the presence of 0.5 U / mL to 2 U / mL FVIII. In further embodiments, the antibody (or antigen-binding fragment thereof) enhances thrombin formation in the absence of Factor VIII to at least about 2%, at least about 3%, at least about 5%, at least about 7%, or at least about 10% of the level of thrombin formation in normal plasma, i.e., in the presence of physiological levels of Factor VIII.

[182] The antibody or antigen-binding fragment may also be administered to an animal model of thrombin deficiency or hemophilia to characterize TFPI inhibitory activity in vivo. Such in vivo models are known in the art and include for example, mice administered anti-FVI II antibodies to induce hemophilia A (Tranholm et al., Blood, 102, 3615-3620 (2003)); coagulation factor knock-out models such as, but not limited to, FVIII knock-out mice (Bi et al., Nat. Genet., 10(1), 1 19-121 (1995)) and FIX knock-out mice (Wang et al., Proc. Nat. Acad. Sci. USA 94(21): 1 1563-1 1566 (1997)); induced hemophilia-A in rabbits (Shen et al., Blood, 42(4):509-521 (1973)); and Chapel Hill HA dogs (Lozier et al., Proc. Nat. Acad. Sci. USA 99: 12991-12996 (2002)).

[183] In certain embodiments, the antibodies (or antigen-binding fragments) disclosed herein enhances FXa activity in the presence of TFPI, with a half maximal effective concentration (EC50) of no more than 1 *10"4 M, no more than 1 *10"5 M, no more than 1 *10"6 M, no more than 1 *10"7 M, no more than 1 *10"8 M, no more than 1 *10"9 M, no more than 1 x10~10 M, no more than 1 x10"11 M, or no more than 1 x10~12 M. Preferably the EC50 is from about 5*10"7 M to 1 x10~11 M, such as from about 1 x10"7 M to 5x10~10 M, from about 1 x10"7 M to 1 x10~10 M, 1 x10"7 M to 5x10~9 M, 5x10"7 M to 5x10"10 M, from about 5x10~7 M to 1 x10"10 M, or from about 5x10"7 M to 5x10~9 M.

[184] In certain embodiments, the antibodies (or antigen-binding fragments) disclosed herein neutralizes the TFPI inhibition of the FVMa / TF mediated FX activation, with a half maximal effective concentration (EC50) of no more than 1 x10"4 M, no more than 1 x10"5 M, no more than 1 x10"6 M, no more than 1 x10~7 M, no more than 1 x10"8 M, no more than 1 x10~9 M, no more than 1 x10"10 M, no more than 1 x10~11 M, or no more than 1 x10~12 M. Preferably the EC50 is from about 5x10~7 M to 1 x10"11 M, such as from about 1 x10"7 M to 5x10"10 M, from about 1 x10"7 M to 1 x10"10 M, 1 x10"7 M to 5x10"9 M, 5x10"7 M to 5x10~10 M, from about 5x10~7 M to 1 x10~10 M, or from about 5x10~7 M to 5x10"9 M.

[185] In certain embodiments, the antibodies (or antigen-binding fragments) disclosed herein decreases the clotting time as measured in a plasma based dilute prothrombin time assay, with a half maximal effective concentration (EC50) of no more than 1 x10"4 M, no more than 1 x10~5 M, no more than 1 x10"6 M, no more than 1 x10"7 M, no more than 1 x10~8 M, no more than 1 x10"9 M, no more than 1χ10~10 M, no more than 1x10~11 M, or no more than 1x10~12 M. Preferably the EC50 is from about 5χ10~7 M to 1χ10"11 M, such as from about 1χ10"7 M to 5χ10"10 M, from about 1χ10"7 M to 1x10"10 M, 1x10"7 M to 5x10"9 M, 5x10~7 M to 5x10"10 M, from about 5x10"7 M to 1x10~10 M, or from about 5x 10"7 M to 5x 10"9 M.

[186] In certain embodiments, the antibodies (or antigen-binding fragments) disclosed herein increases thrombin generation velocity index, with a half maximal effective concentration (EC50) of no more than 1x10~4 M, no more than 1χ10"5 M, no more than 1x10~6 M, no more than 1χ10"7 M, no more than 1χ10"8 M, no more than 1χ10"9 M, no more than 1χ10"10 M, no more than 1χ10"11 M, or no more than 1x10~12 M. Preferably the EC50 is from about 5x10~7 M to 1χ10"11 M, such as from about 1x10"7 M to 5x10"10 M, from about 1x10"7 M to 1x10"10 M, 1 x10"7 M to 5x10"9 M, 5x10"7 M to 5x10"10 M, from about 5x10"7 M to 1x10~10 M, or from about 5x10"7 M to 5x10~9 M.

[187] In certain embodiments, the antibody and antibody fragments disclosed herein may also be further assessed by other biological activity assays, e.g., in order to evaluate its potency, pharmacological activity, and potential efficacy as a therapeutic agent. Such assays are known in the art and depend on the target antigen and intended use for the antibody. Examples include e.g., tumor cell growth inhibition assays; antibody-dependent cellular cytotoxicity (ADCC) and complement-mediated cytotoxicity (CDC) assays; agonistic activity or antagonist activity assays.C. Polynucleotides, vectors, and host cells

[188] The invention also provides polynucleotides encoding any of the TFPI binding antibodies of the disclosure, including antibody fragments and modified antibodies described herein, such as, e.g., antibodies having impaired Fc effector function. In another aspect, the invention provides a method of making any of the polynucleotides described herein. Polynucleotides can be made and expressed by procedures known in the art. Accordingly, the invention provides polynucleotides or compositions, including pharmaceutical compositions, comprising polynucleotides, encoding any of the TFPI antibodies and antigen-binding fragments thereof of the invention.

[189] In one embodiment, the VH and VL domains, or antigen-binding fragment thereof, or full length HC or LC, are encoded by separate polynucleotides. Alternatively, both VH and VL, or antigen-binding fragment thereof, or HC and LC, are encoded by a single polynucleotide.

[190] The invention provides polynucleotides, or compositions comprising the polynucleotides, encoding any of the TFPI antibodies and antigen-binding fragments thereof of the invention, including, but not limited to, TFPI-23, TFPI-24, TFPI-106, TFPI-107, and 4D8, wherein the sequence of the polynucleotide encompasses the sequence of SEQ ID NO:175 (encoding TFPI- 106 VH region), SEQ ID NO:176 (encoding TFPI-106 VL region), SEQ ID NO: 177 (encoding TFPI-106 Heavy Chain), and SEQ ID NO:178 (encoding TFPI-106 Light Chain).

[191] In another aspect, the invention provides an isolated nucleic acid encoding the VH region of an antibody, or an antigen-binding portion thereof, that specifically binds TFPI, comprising the nucleic acid sequence of the insert present in the plasmid deposited as ATCC Accession No. PTA-122329.

[192] In another aspect, the invention provides an isolated nucleic acid encoding the VL region of an antibody, or an antigen-binding portion thereof, that specifically binds TFPI, comprising the nucleic acid sequence of the insert present in the plasmid deposited as ATCC Accession No. PTA- 122328.

[193] In another aspect, the invention provides polynucleotides and variants thereof encoding a TFPI antibody, or portion thereof, wherein such variant polynucleotides comprise a nucleic acid sequence sharing at least 70%, at least 75%, at least 80%, at least 85%, at least 87%, at least 89%, 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% sequence identity to any of the specific nucleic acid sequences disclosed herein. The degree of sequence identity over any length of nucleotide sequence can be calculated using methods familiar to those of ordinary skill in the art. In one non- limiting embodiment, percent sequence identity between two or more related nucleotide sequences can be determined using the nucleotide BLAST server available from the National Library of Medicine (http: / / blast.ncbi.nlm.nih.gov / ). This software provides different settings that one of ordinary skill can use to optimize sequence comparisons depending on such factors as length, complexity, and other factors.

[194] The invention provides a nucleic acid molecule comprising a nucleotide sequence encoding an amino acid sequence of any TFPI antibody, and antigen-biding fragment thereof, of the invention, including, but not limited to, an amino acid sequence of an antibody, or antigen-binding fragment thereof, provided in Table 33 (e.g., an amino acid sequence of SEQ ID NOs:21-174), and any antibody that binds the same epitope as and / or competes for binding of TFPI with an antibody of the invention.

[195] In another aspect, the invention provides polynucleotides and variants thereof encoding a TFPI antibody, wherein such variant polynucleotides encode an amino acid sequence sharing at least 70%, at least 75%, at least 80%, at least 85%, at least 87%, at least 89%, 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% sequence identity to any TFPI antibody amino acid sequence disclosed herein.

[196] In other embodiments, the degree of relatedness between nucleic acids comprising a variant polynucleotide sequence encoding a TFPI antibody, or portion thereof, and any of the specific nucleotide sequences disclosed herein can be determined by testing if the variant sequence (or complement thereto) can hybridize with a specific nucleotide sequence (or complement thereto) under moderate or highly stringent conditions in a Northern blot or Southern blot assay format. Exemplary and non-limiting "moderately stringent conditions" include prewashing in a solution of 5 X SSC, 0.5% SDS, 1.0 mM EDTA (pH 8.0); hybridizing at 50°C-65°C, 5 X SSC, overnight; followed by washing twice at 65°C for 20 minutes with each of 2X, 0.5X and 0.2X SSC containing 0.1 % SDS.

[197] Exemplary and non-limiting, "highly stringent conditions" or "high stringency conditions" are those that: (1) employ low ionic strength and high temperature for washing, for example 0.015 M sodium chloride / 0.0015 M sodium citrate / 0.1 % sodium dodecyl sulfate at 50°C; (2) employ during hybridization a denaturing agent, such as formamide, for example, 50% (v / v) formamide with 0.1 % bovine serum albumin / 0.1 % Ficoll / 0.1 % polyvinylpyrrolidone / 50 mM sodium phosphate buffer at pH 6.5 with 750 mM sodium chloride, 75 mM sodium citrate at 42°C; or (3) employ 50% formamide, 5 x SSC (0.75 M NaCI, 0.075 M sodium citrate), 50 mM sodium phosphate (pH 6.8), 0.1 % sodium pyrophosphate, 5 x Denhardt's solution, sonicated salmon sperm DNA (50 μg / ml), 0.1 % SDS, and 10% dextran sulfate at 42°C, with washes at 42°C in 0.2 x SSC (sodium chloride / sodium citrate) and 50% formamide at 55°C, followed by a high-stringency wash consisting of 0.1 x SSC containing EDTA at 55°C. The skilled artisan will recognize how to adjust the temperature, ionic strength, etc. as necessary to accommodate factors such as probe length and the like. One of ordinary skill in the art will also be familiar with standard techniques for conducting a Northern blot or Southern blot assay to detect the degree of relatedness between variant a nucleotide sequence and a specific nucleotide sequence of the disclosure.

[198] Polynucleotides complementary to any such sequences are also encompassed by the present invention. Polynucleotides may be single-stranded (coding or antisense) or double- stranded, and may be DNA (genomic, cDNA or synthetic) or RNA molecules. RNA molecules include hnRNA molecules, which contain introns and correspond to a DNA molecule in a one-to- one manner, and mRNA molecules, which do not contain introns. Additional coding or non-coding sequences may, but need not, be present within a polynucleotide of the present invention.

[199] Variants may also, or alternatively, be substantially homologous to a native gene, or a portion or complement thereof. Such polynucleotide variants are capable of hybridizing under moderately stringent conditions to a naturally occurring DNA sequence encoding a native antibody (or a complementary sequence).

[200] It will be appreciated by those of ordinary skill in the art that, as a result of the degeneracy of the genetic code, there are many nucleotide sequences capable of encoding any of the TFPI antibodies, or portions thereof, disclosed herein. Some of these polynucleotides may bear a relatively low degree of sequence identity to any of the specific nucleotide sequences for TFPI antibodies provided herein, while encoding the same amino acid sequence. Nonetheless, polynucleotides that vary due to differences in codon usage are specifically contemplated by the present invention.

[201] The polynucleotides of this invention can be obtained using chemical synthesis, recombinant methods, or PCR. Methods of chemical polynucleotide synthesis are well known in the art and need not be described in detail herein. One of skill in the art can use the sequences provided herein and a commercial DNA synthesizer to produce a desired DNA sequence.

[202] For preparing polynucleotides using recombinant methods, a polynucleotide comprising a desired sequence can be inserted into a suitable vector, and the vector in turn can be introduced into a suitable host cell for replication and amplification, as further discussed herein.Polynucleotides may be inserted into host cells by any means known in the art. Cells can be transformed by introducing an exogenous polynucleotide by direct uptake, endocytosis, transfection, F-mating or electroporation. Once introduced, the exogenous polynucleotide can be maintained within the cell as a non-integrated vector (such as a plasmid) or integrated into the host cell genome. The polynucleotide so amplified can be isolated from the host cell by methods well known within the art. See, e.g., Sambrook et al., 1989.

[203] Alternatively, PCR allows reproduction of DNA sequences. PCR technology is well known in the art and is described in U.S. Patent Nos. 4,683, 195, 4,800, 159, 4,754,065 and 4,683,202, as well as PCR: The Polymerase Chain Reaction, Mullis et al. eds., Birkauswer Press, Boston, 1994.

[204] RNA can be obtained by using the isolated DNA in an appropriate vector and inserting it into a suitable host cell. When the cell replicates and the DNA is transcribed into RNA, the RNA can then be isolated using methods well known to those of skill in the art, as set forth in Sambrook et al., 1989, supra, for example.

[205] Suitable cloning vectors may be constructed according to standard techniques, or may be selected from a large number of cloning vectors available in the art. While the cloning vector selected may vary according to the host cell intended to be used, useful cloning vectors will generally have the ability to self-replicate, may possess a single target for a particular restriction endonuclease, and / or may carry genes for a marker that can be used in selecting clones containing the vector. Suitable examples include plasmids and bacterial viruses, e.g., pUC18, pUC19, Bluescript (e.g., pBS SK+) and its derivatives, mp18, mp19, pBR322, pMB9, ColE1 , pCR1 , RP4, phage DNAs, and shuttle vectors such as pSA3 and pAT28. These and many other cloning vectors are available from commercial vendors such as BioRad, Stratagene, and Invitrogen.

[206] Expression vectors are further provided. Expression vectors generally are replicable polynucleotide constructs that contain a polynucleotide according to the invention. It is implied that an expression vector must be replicable in the host cells either as episomes or as an integral part of the chromosomal DNA. Suitable expression vectors include but are not limited to plasmids, viral vectors, including adenoviruses, adeno-associated viruses, retroviruses, cosmids, and expression vector(s) disclosed in PCT Publication No. WO 87 / 04462. Vector components may generally include, but are not limited to, one or more of the following: a signal sequence; an origin of replication; one or more marker genes; suitable transcriptional controlling elements (such as promoters, enhancers and terminator). For expression (i.e., translation), one or more translational controlling elements are also usually required, such as ribosome binding sites, translation initiation sites, and stop codons.

[207] The vectors containing the polynucleotides of interest and / or the polynucleotides themselves, can be introduced into the host cell by any of a number of appropriate means, including electroporation, transfection employing calcium chloride, rubidium chloride, calcium phosphate, DEAE-dextran, or other substances; microprojectile bombardment; lipofection; and infection (e.g., where the vector is an infectious agent such as vaccinia virus). The choice of introducing vectors or polynucleotides will often depend on features of the host cell.

[208] The invention also provides host cells comprising any of the polynucleotides described herein. Any host cells capable of over-expressing heterologous DNAs can be used for the purpose of isolating the genes encoding the antibody, polypeptide or protein of interest. Non-limiting examples of mammalian host cells include but not limited to simian COS, human HeLa, human embryonic kidney (HEK) 293, Sp2.0 and Chinese hamster ovary (CHO) cells. See also PCT Publication No. WO 87 / 04462. Suitable non-mammalian host cells include prokaryotes (such as E. coli or B. subtillis) and yeast (such as S. cerevisae, S. pombe; or K. lactis). Screening for host cells expressing a TFPI antibody, or antigen binding portion thereof, can be detected using an immune- binding assay, such as ELISA, FACS, or other assay familiar to those of ordinary skill in the art.

[209] Thus, the antibody (or antigen-binding fragment thereof) of the invention may be recombinantly produced using a suitable host cell. Nucleic acid encoding the antibody or antigen- binding fragment thereof can be cloned into an expression vector, which can then be introduced into a host cell, such as E. coli cell, a yeast cell, an insect cell, a COS cell, a CHO cell, or a myeloma cell that do not otherwise produce immunoglobulin protein, to obtain the synthesis of monoclonal antibodies in the recombinant host cells. Exemplary host cells include CHO cell, HEK 293, and Sp2.0 cells.

[210] An expression vector can be used to direct expression of a TFPI antibody. One skilled in the art is familiar with administration of expression vectors to obtain expression of an exogenous protein in vivo. See, e.g., U.S. Patent Nos. 6,436,908; 6,413,942; and 6,376,471. Administration of expression vectors includes local or systemic administration, including injection, oral administration, particle gun or catheterized administration, and topical administration. According to certain non- limiting embodiments, the expression vector is administered directly to the liver, skeletal muscles, bone marrow, or other tissues.

[211] Targeted delivery of therapeutic compositions containing an expression vector, or subgenomic polynucleotides can also be used. Receptor-mediated DNA delivery techniques are described in, for example, Findeis et al., Trends Biotechnol., 1993, 1 1 :202; Chiou et al., Gene Therapeutics: Methods And Applications Of Direct Gene Transfer, J.A. Wolff, ed., 1994; Wu et al., J. Biol. Chem., 1988, 263:621 ; Wu et al., J. Biol. Chem., 1994, 269:542; Zenke et al., Proc. Natl. Acad. Sci. USA, 1990, 87:3655; Wu et al., J. Biol. Chem., 1991 , 266:338. Therapeuticcompositions containing a polynucleotide are administered in a range of about 100 ng to about 200 mg of DNA for local administration in a gene therapy protocol. Concentration ranges of about 500 ng to about 50 mg, about 1 μg to about 2 mg, about 5 μg to about 500 μg, and about 20 μg to about 100 μg of DNA can also be used during a gene therapy protocol. The therapeuticpolynucleotides and polypeptides can be delivered using gene delivery vehicles. The gene delivery vehicle can be of viral or non-viral origin (see generally, Jolly, Cancer Gene Therapy, 1994, 1 :51 ; Kimura, Human Gene Therapy, 1994, 5:845; Connelly, Human Gene Therapy, 1995, 1 :185; and Kaplitt, Nature Genetics, 1994, 6:148). Expression of such coding sequences can be induced using endogenous mammalian or heterologous promoters. Expression of the coding sequence can be either constitutive or regulated.

[212] Viral-based vectors for delivery of a desired polynucleotide and expression in a desired cell are well known in the art. Exemplary viral-based vehicles include, but are not limited to,recombinant retroviruses (see, e.g., PCT Publication Nos. WO 90 / 07936; WO 94 / 03622; WO 93 / 25698; WO 93 / 25234; WO 93 / 1 1230; WO 93 / 10218; WO 91 / 02805; U.S. Patent Nos. 5, 219,740 and 4,777, 127; GB Patent No. 2,200,651 ; and EP Patent No. 0 345 242), alphavirus- based vectors (e.g., Sindbis virus vectors, Semliki forest virus (ATCC VR-67; ATCC VR-1247), Ross River virus (ATCC VR-373; ATCC VR-1246) and Venezuelan equine encephalitis virus (ATCC VR-923; ATCC VR-1250; ATCC VR 1249; ATCC VR-532)), and adeno-associated virus (AAV) vectors (see, e.g., PCT Publication Nos. WO 94 / 12649, WO 93 / 03769; WO 93 / 19191 ; WO 94 / 28938; WO 95 / 11984 and WO 95 / 00655). Administration of DNA linked to killed adenovirus as described in Curiel, Hum. Gene Ther., 1992, 3:147 can also be employed.

[213] Non-viral delivery vehicles and methods can also be employed, including, but not limited to, polycationic condensed DNA linked or unlinked to killed adenovirus alone (see, e.g., Curiel, Hum. Gene Ther., 1992, 3:147); ligand-linked DNA (see, e.g., Wu, J. Biol. Chem., 1989, 264:16985); eukaryotic cell delivery vehicles cells (see, e.g., U.S. Patent No. 5,814,482; PCT Publication Nos. WO 95 / 07994; WO 96 / 17072; WO 95 / 30763; and WO 97 / 42338) and nucleic charge neutralization or fusion with cell membranes. Naked DNA can also be employed. Exemplary naked DNA introduction methods are described in PCT Publication No. WO 90 / 1 1092 and U.S. Patent No. 5,580,859. Liposomes that can act as gene delivery vehicles are described in U.S. Patent No. 5,422, 120; PCT Publication Nos. WO 95 / 13796; WO 94 / 23697; WO 91 / 14445; and EP 0524968. Additional approaches are described in Philip, Mol. Cell Biol., 1994, 14:241 1 , and in Woffendin, Proc. Natl. Acad. Sci., 1994, 91 : 1581.

[214] The sequence of a desired antibody (or antigen-binding fragment thereof), and nucleic acid encoding such antibody (or antigen-binding fragment thereof), can be determined using standard sequencing techniques. Nucleic acid sequence encoding a desired antibody (or fragments) may be inserted into other vectors (such as cloning and expression vectors) for recombinant production and characterization. Heavy chain (or a fragment of the heavy chain) and light chain (or a fragment of the light chain) can be cloned in the same vector, or different vectors.

[215] Suitable cloning and expression vectors can include a variety of components, such as promoter, enhancer, and other transcriptional regulatory sequences. The vector may also be constructed to allow for movement of antibody variable domain between different vectors.

[216] Antibody fragments can be produced by proteolytic or other degradation of the antibodies, by recombinant methods, or by chemical synthesis. Polypeptides of the antibodies, especially shorter polypeptides up to about 50 amino acids, are conveniently made by chemical synthesis. Methods of chemical synthesis are known in the art and are commercially available.

[217] The antibody or antigen-binding fragment thereof disclosed herein may be affinity-matured. For example, affinity matured antibodies can be produced by procedures known in the art (Marks et al., 1992, Bio / Technology, 10:779-783; Barbas et al., 1994, Proc. Nat. Acad. Sci. USA 91 :3809- 3813; Schier et al., 1995, Gene, 169:147-155; Yelton et al., 1995, J. Immunol., 155:1994-2004; Jackson et al., 1995, J. Immunol., 154(7):3310-3319; Hawkins et al., 1992, J. Mol. Biol., 226:889- 896; and WO2004 / 058184).4. FORMULATIONS AND USES

[218] Antibodies or antigen-binding fragments described herein can be formulated aspharmaceutical formulations. The pharmaceutical formulation may further comprisepharmaceutically acceptable carriers, excipients, or stabilizers (Remington: The Science and practice of Pharmacy 20th Ed., 2000, Lippincott Williams and Wilkins, Ed. K. E. Hoover), in the form of lyophilized formulations or aqueous solutions. Acceptable carriers, excipients, or stabilizers are nontoxic to recipients at the dosages and concentrations, and may comprise buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride, benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrans; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counter-ions such as sodium; metal complexes (e.g. Zn-protein complexes); and / or non-ionic surfactants such as TWEEN™, PLURONICS™ or polyethylene glycol (PEG). Pharmaceutically acceptable excipients are further described herein.

[219] The antibodies or antigen-binding fragments described herein can be used for various therapeutic or diagnostic purposes. For example, the antibody or antigen-binding fragment thereof may be used as an affinity purification agents (e.g., for in vitro purification of TFPI), as a diagnostic agent (e.g., for detecting expression of TFPI in specific cells, tissues, or serum).

[220] Exemplary therapeutic uses of the antibody and antibody fragments of the invention include treating thrombocytopenia, platelet disorders (disorders of platelet function or number), and bleeding disorders (e.g., hemophilia A, hemophilia B and hemophilia C). The antibodies and antibody fragments may also be used for treating uncontrolled bleeding in indications such as trauma and hemorrhagic stroke. The antibodies and antibody fragments may also be used in prophylactic treatment (e.g., before surgeries).

[221] In particular, antibodies or antigen-binding fragments described herein can be used to treat deficiencies or defects in coagulation. For example, the antibodies or antigen-binding fragments described herein may be used to reduce or inhibit the interaction of TFPI with FXa, or to reduce TFPI-dependent inhibition of the TF / FVIIa / FXa activity.

[222] For therapeutic applications, antibodies or antigen-binding fragments described herein can be administered to a mammal, especially a human by conventional techniques, such as intravenously (as a bolus or by continuous infusion over a period of time), intramuscularly, intraperitoneally, intra-cerebrospinally, subcutaneously, intra-articularly, intrasynovially, intrathecally, orally, topically, or by inhalation. The antibodies or antigen-binding fragments also are suitably administered by intra-tumoral, peri-tumoral, intra-lesional, or peri-lesional routes.

[223] Accordingly, in one aspect, the invention provides a method of reducing the activity of Tissue Factor Pathway Inhibitor (TFPI), comprising administering to a subject in need thereof a therapeutically effective amount of the antibodies or antigen-binding fragments described herein. In another aspect, the invention provides a method of shortening bleeding time, comprising administering to a subject in need thereof a therapeutically effective amount of the antibodies or antigen-binding fragments described herein.

[224] In certain embodiments, the subject is a human.

[225] In certain embodiments, the subject suffers from or is susceptible to a deficiency in blood coagulation. Deficiency in blood coagulation includes, e.g., von Willebrand disease (vWD), hemophilia A, B, or C, and other platelet disorders (such as congenital platelet defects, congenital and acquired storage pool deficiency, prolonged bleeding time).

[226] In certain embodiments, the antibodies or antigen-binding fragments described herein is administered subcutaneously. In certain embodiments, the antibodies or antigen-binding fragments described herein is administered intravenously.

[227] The pharmaceutical compositions may be administered to a subject in need thereof at a frequency that may vary with the severity of the bleeding episode or, in the case of prophylactic therapy, may vary with the severity of the patient's clotting deficiency.

[228] The compositions may be administered to patients in need as a bolus or by continuous infusion. For example, a bolus administration of an antibody present as a Fab fragment may be in an amount of from 0.0025 to 100 mg / kg body weight, 0.025 to 0.25 mg / kg, 0.010 to 0.10 mg / kg or 0.10-0.50 mg / kg. For continuous infusion, an antibody present as an Fab fragment may be administered at 0.001 to 100 mg / kg body weight / minute, 0.0125 to 1.25 mg / kg / min, 0.010 to 0.75 mg / kg / min, 0.010 to 1.0 mg / kg / min. or 0.10-0.50 mg / kg / min for a period of 1-24 hours, 1-12 hours, 2-12 hours, 6-12 hours, 2-8 hours, or 1-2 hours.

[229] For administration of an antibody present as a full-length antibody (with full constant regions), dosage amounts may be from about 1 mg / kg to about 10 mg / kg, from about 2 mg / kg to about 10 mg / kg, from about 3 mg / kg to about 10 mg / kg, from about 4 mg / kg to about 10 mg / kg, from about 5 mg / kg to about 10 mg / kg, from about 1 mg / kg to about 20 mg / kg, from about 2 mg / kg to about 20 mg / kg, from about 3 mg / kg to about 20 mg / kg, from about 4 mg / kg to about 20 mg / kg, from about 5 mg / kg to about 20 mg / kg, about 1 mg / kg or more, about 2 mg / kg or more, about 3 mg / kg or more, about 4 mg / kg or more, about 5 mg / kg or more, about 6 mg / kg or more, about 7 mg / kg or more, about 8 mg / kg or more, about 9 mg / kg or more, about 10 mg / kg or more, about 1 1 mg / kg or more, about 12 mg / kg or more, about 13 mg / kg or more, about 14 mg / kg or more, about 15 mg / kg or more, about 16 mg / kg or more, about 17 mg / kg or more, about 19 mg / kg or more, or about 20 mg / kg or more. The frequency of the administration would depend upon the severity of the condition. Frequency could range from three times per week to once every two or three weeks.

[230] Additionally, the compositions may be administered to patients via subcutaneous injection. For example, a dose of 1 to 100 mg anti-TFPI antibody can be administered to patients via subcutaneous injection once every day, once every 2 days, once every 3 days, once every 4 days, once every 5 days, once every 6 days, twice a week, weekly, biweekly, or monthly.

[231] In certain embodiments, the pharmaceutical composition is administered subcutaneous by a weekly schedule, with a dose from about 0.1 mg / kg to about 10 mg / kg, from about 0.5 mg / kg to about 10 mg / kg, from about 1 mg / kg to about 10 mg / kg, from about 1.5 mg / kg to about 10 mg / kg, from about 2 mg / kg to about 10 mg / kg, from about 0.1 mg / kg to about 8 mg / kg, from about 0.5 mg / kg to about 8 mg / kg, from about 1 mg / kg to about 8 mg / kg, from about 1.5 mg / kg to about 8 mg / kg, from about 2 mg / kg to about 8 mg / kg, from about 0.1 mg / kg to about 5 mg / kg, from about 0.5 mg / kg to about 5 mg / kg, from about 1 mg / kg to about 5 mg / kg, from about 1.5 mg / kg to about 5 mg / kg, from about 2 mg / kg to about 5 mg / kg, about 0.5 mg / kg, about 1.0 mg / kg, about 1.5 mg / kg, about 2.0 mg / kg, about 2.5 mg / kg, about 3.0 mg / kg, about 3.5 mg / kg, about 4.0 mg / kg, about 4.5 mg / kg, about 5.0 mg / kg, about 5.5 mg / kg, about 6.0 mg / kg, about 6.5 mg / kg, about 7.0 mg / kg, about 7.5 mg / kg, about 8.0 mg / kg, about 8.5 mg / kg, about 9.0 mg / kg, about 9.5 mg / kg, or about 10.0 mg / kg.

[232] In certain embodiments, the pharmaceutical composition is administered subcutaneous by a weekly schedule, with a dose of about 2.0 mg / kg. In certain embodiments, the pharmaceutical composition is administered subcutaneous by a weekly schedule, with a dose of about 3.0 mg / kg.

[233] The antibodies and antibody fragments described herein can be used as monotherapy or in combination with other therapies to address a hemostatic disorder. For example, co-administration of one or more antibodies (or antibody fragments) of the invention with a clotting agent such as factor Vila, factor VIII, factor IX or tranexamic acid may be useful for treating hemophilia.

[234] In one embodiment, provided is a method for treating a deficiency in coagulation or shortening bleeding time, comprising administering (a) a first amount of the antibody or antigen- binding fragment of the invention, and (b) a second amount of factor VIII or factor IX. Optionally, factor VII is not co-administered. In another embodiment, provided is a method for treating a deficiency in coagulation or shortening bleed time, comprising administering (a) a first amount of the antibody or antigen-binding fragment of the invention and (b) a second amount of factor VIII or factor IX. Optionally, factor VII is not co-administered. One skilled in the art would appreciate that in treating a deficiency in coagulation, a shortening in bleeding time can also be referred to as a shortening in clotting time.

[235] The invention also includes a pharmaceutical composition comprising a therapeutically effective amount of the combination of an antibody (or antibody fragment) of the invention and factor VIII or factor IX, wherein the composition does not comprise factor VII. "Factor VII" includes factor VII and factor Vila.BIOLOGICAL DEPOSIT

[236] Representative materials of the present invention were deposited in the American Type Culture Collection, 10801 University Boulevard, Manassas, Va. 201 10-2209, USA, on July 22, 2015. Plasmid vector mAb-TFPI-106 VH having ATCC Accession No. PTA-122329 comprises a DNA insert encoding the heavy chain variable region of antibody TFPI-106, and plasmid vector mAb-TFPI-106 VL having ATCC Accession No. PTA-122328 comprises a DNA insert encoding the light chain variable region of antibody TFPI-106. The deposits were made under the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purpose of Patent Procedure and Regulations thereunder (Budapest Treaty). This assures maintenance of a viable culture of the deposit for 30 years from the date of deposit. The deposit will be made available by ATCC under the terms of the Budapest Treaty, and subject to an agreement between Pfizer Inc. and ATCC, which assures permanent and unrestricted availability of the progeny of the culture of the deposit to the public upon issuance of the pertinent U.S. patent or upon laying open to the public of any U.S. or foreign patent application, whichever comes first, and assures availability of the progeny to one determined by the U.S. Commissioner of Patents and Trademarks to be entitled thereto according to 35 U.S.C. Section 122 and the Commissioner's rules pursuant thereto (including 37 C.F.R. Section 1.14 with particular reference to 886 OG 638).

[237] The assignee of the present application has agreed that if a culture of the materials on deposit should die or be lost or destroyed when cultivated under suitable conditions, the materials will be promptly replaced on notification with another of the same. Availability of the deposited material is not to be construed as a license to practice the invention in contravention of the rights granted under the authority of any government in accordance with its patent laws.EXAMPLES

[238] The invention is further described in detail by reference to the following experimental examples. These examples are provided for purposes of illustration only, and are not intended to be limiting unless otherwise specified. Thus, the invention should in no way be construed as being limited to the following examples, but rather, should be construed to encompass any and all variations which become evident as a result of the teaching provided herein.EXAMPLE 1. EXPERIMENTAL MATERIALS AND METHODS1. TFPI protein reagents

[239] Protein reagents used for immunization, phage display selection and characterization of anti- TFPI antibodies are listed in Table 1 , and their sequence IDs are listed in Table 2.

[240] The TFPI constructs (pSMED2 vector) were expressed transiently in HEK293F cells and conditioned media was harvested 120 hours post transfection. The protein of interest was captured from conditioned media using Nickel Sepharose HP and further purified by size exclusion chromatography. Factor Xa and Factor X were obtained from Haematologic Technologies, Inc. The chromogenic substrate for the for the amidolytic assay of Factor Xa, Spectrozyme®FXa was obtained from Sekisui Diagnostics.Table 1Protein reagents used for immunization, phage display selection and identification of anti-TFPI antibodiesSeqID (see table 2)Protein Reagent Species Secretory TFPI C-terminal tagLeaderhumTFPI K1K2 human 9 1 8humTFPI K1K2K3 human 9 2 8humTFPI2 K1K2K3 human 9 3 8murTFPI K1K2 mouse 9 4 8cynTFPI K1K2 cynomolgus 9 5 8 monkeyrabTFPI K1K2 rabbit 9 6 8 ratTFPI K1K2 rat 9 7 8Table 2TFPI reagent sequence identification numbers, descriptions and sequences2. Antibody reagents

[241] The monoclonal antibodies used for comparative purposes (reference antibodies 2A8, 2A8- 200, 3F18, hz4F36) are listed in Table 3. The antibody descriptions, sources and sequences are listed in Table 4 (Figure 5). The light chain and heavy chain sequences were cloned into the appropriate vectors and were expressed transiently in Human Embryonic Kidney-293 (HEK-293) cells, and purified by Protein A Sepharose and size exclusion chromatography. Mab 2974 was obtained from R&D Systems (catalog # MAB2974).Table 3Antibody sequence identification numbers (SeqID) for light chain (LC) CDR1 ,2,3, variable light (VL), constant light (CL), light chain (LC), heavy chain (HC) CDR1 ,2,3, variable heavy (VH), constant heavy (CH) and heavy chain (HC) regions. Sequence compositions for SeqID numbers are in Table 4.Light Chain SeqID (See Table 4 ) Heavy Chain SeqID (See Table 4)Antibody LC LC LC VL CL LC HC HC HC VH CH HCCDR CDR CDR CDR CDR CDR1 2 3 1 2 3TFPI-3 10 11 12 13 14 15 16 17 18 19 20 21TFPI-21 22 23 24 25 26 27 28 29 30 31 20 32TFPI-23 33 34 35 36 26 37 38 39 40 41 20 42TFPI-24 43 44 45 46 26 47 48 49 50 51 20 52TFPI-26 53 54 55 56 26 57 58 59 60 61 20 62TFPI-106 33 34 35 36 26 37 38 39 40 63 20 64TFPI-107 33 34 35 36 26 37 38 39 40 65 20 66TFPI-108 43 44 45 46 26 47 48 49 50 67 20 68TFPI-109 43 44 45 46 26 47 48 49 50 69 20 70TFPI-1 10 43 44 45 71 26 72 48 49 50 51 20 52TFPI-1 11 43 44 45 73 26 74 48 49 50 51 20 52TFPI-1 12 43 44 45 75 26 76 48 49 50 51 20 52TFPI-1 13 43 44 45 77 26 78 48 49 50 51 20 52TFPI-1 14 43 44 45 46 26 47 48 49 50 79 20 80TFPI-1 15 43 44 45 71 26 72 48 49 50 67 20 68TFPI-1 18 43 44 45 77 26 78 48 49 50 67 20 68TFPI-1 19 43 44 45 71 26 72 48 49 50 69 20 70TFPI-122 43 44 45 77 26 78 48 49 50 69 20 70TFPI-123 43 44 45 71 26 72 48 49 50 51 20 52TFPI-126 43 44 45 77 26 78 48 49 50 51 20 524D8.b1 81 82 83 84 85 86 87 88 89 90 91 92 mu-hu 4D8 chimera 81 82 83 84 14 93 87 88 89 90 20 944D8-Vk1.0 x VH1.0 81 82 83 109 14 110 87 88 89 95 20 964D8-Vk1.0 x VH1.1 81 82 83 109 14 110 87 88 89 97 20 984D8-Vk1.0 x VH1.2 81 82 83 109 14 110 87 88 89 99 20 1004D8-Vk1.0 x VH1.3 81 82 83 109 14 110 87 88 89 101 20 1024D8-Vk1.0 x VH1.4 81 82 83 109 14 110 87 88 89 103 20 1044D8-Vk1.0 x VH1.5 81 82 83 109 14 110 87 88 89 105 20 1064D8-Vk1.0 x VH1.6 81 82 83 109 14 110 87 88 89 107 20 1084D8-Vk1.1 x VH1.0 81 82 83 11 1 14 112 87 88 89 95 20 964D8-Vk1.1 x VH1.1 81 82 83 11 1 14 112 87 88 89 97 20 984D8-Vk1.1 x VH1.2 81 82 83 11 1 14 112 87 88 89 99 20 1004D8-Vk1.1 x VH1.3 81 82 83 11 1 14 112 87 88 89 101 20 102 4D8-Vk1 .1 x VH1 .4 81 82 83 1 1 1 14 1 12 87 88 89 103 20 1044D8-Vk1 .1 x VH1 .5 81 82 83 1 1 1 14 1 12 87 88 89 105 20 1064D8-Vk1 .1 x VH1 .6 81 82 83 1 1 1 14 1 12 87 88 89 107 20 108 hz4D8 81 82 83 1 1 1 14 1 12 87 88 89 103 20 1046B7.C5 1 13 1 14 1 15 1 16 85 1 17 1 18 1 19 120 121 91 1227A4.D9 123 124 125 126 85 127 128 129 130 131 91 1322A8 133 134 135 136 26 137 138 139 140 141 20 1422A8-200 143 144 145 146 26 147 148 149 150 151 20 1523F18 153 154 155 156 157 158 159 160 161 162 81 163 hz4F36 164 165 166 167 14 168 169 170 171 172 173 1743. TFPI binding ELISA

[242] Recombinant humTFPI K1 K2, murTFPI K1 K2, cynTFPI K1 K2, ratTFPI K1 K2, rabTFPI K1 K2 or TFPI2 was biotinylated using the AviTag™ system and captured onto Greiner streptavidin- coated 96 well plates at a concentration of 1 x 10"8 M in ELISA assay buffer. Purified anti-TFPI antibodies were diluted to 1 ug / ml in ELISA assay buffer, then serially diluted three-fold to generate an eight-point dilution series. The diluted antibodies were added at a volume of 100 uL per well. The plates were incubated at room temperature for 2 hours. After washing the plates withPBS / 0.05% Tween 20, the plates were incubated with a goat anti-mouse IgG-Fc polyclonal antibody conjugated with horseradish peroxidase (Pierce) at 1 :10,000 dilution. After 1 hour of incubation, bound antibody was detected with the addition of a TMB substrate solution.Absorbances were read a 450 nm, and the data were analyzed by GraphPad Prism software.4. Surface plasmon resonance (SPR)

[243] An anti-human Fc sensor chip was prepared by amine coupling anti-human IgG antibody (catalogue number BR-1008-39, GE Healthcare) to all four flow cells of a carboxymethylated dextran coated sensor chip (CM5) (catalogue number BR100530, GE Healthcare). The flow cells were activated by injecting a 1 : 1 mixture of 400mM 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) for 7 minutes at a flow rate of 10 μΙ / minute. Anti-human IgG antibody was diluted to 25 μg / ml in 10mM Sodium Acetate pH 5.0 and injected over all flow cells for 7 minutes at 10ul / minute. All flow cells were blocked with 1 M Ethanolamine- HCL (ETH) for 7 minutes at 10 μΙ / minute. Final immobilization level of the capture antibody was approximately 10,000 resonance units (RU). The running buffer for immobilization and kinetics was 10mM HEPES pH 7.4, 150mM NaCI, 3mM EDTA, 0.05% (v / v) Tween-20 (HBS-EP+). Tocharacterize the binding of anti-TFPI antibodies to human TFPI, the antibodies were diluted to 0.5 μg / mL in HBS-EP+ and captured by the anti-human IgG immobilized on flow cells 2, 3 and 4 for 30 seconds to 1 minute at a flow rate of δμίΛτπηυΙθ to achieve a capture level of 70 to 300 RU. Flow cell 1 was used as a reference surface. After antibody capture, the flow rate was increased to and buffer or human TFPI ranging in concentration from 0.2nM to 200nM in HBS-EP+ was injected over all flow cells for a 1.0 minute association and allowed to dissociate for 10 to 15 minutes. Buffer cycles collected for each captured antibody were used for double-referencing (Myszka.D.G. J.Mol.Recognit 12, 279-284 (1999)). At the end of each cycle, the entire anti-lgG surface was regenerated by a 60 second pulse of 3M MgCI2. Kinetic assays were conducted at 25°C at a collection rate of 10 Hz on a BIAcore T200 instrument (GE Healthcare). Rate constants and affinities were determined by fitting the data to a 1 : 1 model in BIAcore T200 Evaluation software version 1.0 (GE).5. Factor Xa TFPI inhibition reversal assay

[244] The ability of purified anti-TFPI antibodies to restore Factor Xa activity in the presence of inhibitory concentrations of TFPI was assessed in vitro. Anti-TFPI antibodies diluted in PBS at concentrations ranging from 1 nM - 500 nM were pre-incubated with 10 nM recombinant human TFPI K1 K2 or 10 nM rabbit TFPI K1 K2 proteins in activity buffer (20mM HEPES, pH 8.0, 150mM NaCI, 5mM CaCI2, 0.5mg / ml_ BSA) for 30 minutes at 37°C. 2nM human plasma-derived Factor Xa was added and the reactions were incubated at 37°C for 30 minutes. The chromogenic substrate Spectrozyme Xa was added to a final concentration of 500uM for a final reaction volume of 100uL. Control reactions included reactions without Factor Xa to control for assay background, without TFPI, allowing for maximal generation of FXa (100 % activity) or without anti-TFPI antibody (PBS alone). Absorbances of the reactions were immediately read on a SpectraMax M5e multi-mode plate reader at a wavelength of 405nm at 2 minute intervals over a period of 60 minutes. EC50s were calculated with Prism Graph Pad software.6. Two-stage TF-FVIIa-FX inhibition reversal assay

[245] The ability of purified anti-TFPI antibodies to restore Factor Vila-Tissue Factor activity in the presence of inhibitory concentrations of TFPI was assessed in vitro. Anti-TFPI antibodies at concentrations ranging from 1 nm - 500 nM were pre-incubated with 10 nM recombinant TFPI proteins in activity buffer for 30 minutes at 37°C. Approximately 1 pM lipidated tissue factor and 1 nM recombinant Factor Vila (NovoSeven) were added to the reactions and incubated at 37°C for 5 minutes. 150 nM Human Factor X was introduced into the reactions. The chromogenic substrate Spectrozyme Xa was added to a final concentration of 500uM to each well for a final reaction volume of 100uL. Control reactions included reactions without Factor Vila, without Tissue Factor, without Factor X, without TFPI or without anti-TFPI antibody (PBS alone). Absorbances of the reactions were immediately read on a SpectraMax M5e multi-mode plate reader at a wavelength of 405nm at a 2 minute intervals over a period of 60 minutes. EC50s were calculated with Prism Graph Pad software. 7. Thrombin generation assay (TGA)

[246] The ability of purified anti-TFPI antibodies to restore thrombin generation in plasma with attenuated Factor VIII activity was assessed in thrombin generation assays using the Calibrated Automated Thrombogram (CAT) system. Anti-TFPI antibodies at concentrations of 1 nm-500 nm diluted in PBS were introduced into reactions containing human Factor VIII deficient plasma and PPP-Low reagent, containing 4 uM phospholipid and 1 pM Tissue Factor. Control reactions used PBS without antibody. Reactions were triggered with addition of Fluca buffer containing a fluorogenic thrombin substrate and CaCI2. Fluorescence of each reaction was immediately read using a Fluoroskan Ascent plate reader using Thrombinoscope software at a 20 second interval for 60 minutes. Each reaction was compared to a calibrator control well containing PBS, thrombin calibrator, FVIII deficient plasma and FLUCA buffer. Thrombinoscope Thrombin generation curves (nM thrombin versus time) were analyzed to extract lag time, peak height, time to peak and the area under the curve or endogenous thrombin potential (ETP) using the Thrombinoscope software (Thrombinoscope BV version). The data were used to calculate velocity index (Peak thrombin concentration / Time to Peak - Lag Time).

[247] The ability of purified anti-TFPI antibodies to restore thrombin generation in rabbit plasma with attenuated FVIIIa activity was also assessed. Normal New Zealand white rabbit plasma were treated with anti-FVI II antibody (GM-8015) at a final concentration of 100ug / ml or control mouse anti-human lgG2a at 100ug / mL for 60 minutes at 37°C. Immediately prior to addition into reaction wells, rabbit plasma was diluted 1 :3 into buffer (20mM HEPES, 140mM NaCI). Thrombin generation assays with the FVIII neutralized rabbit plasma were performed as described above.8. Generation of cynomolgus TFPI K2 domain for structural studies

[248] Cynomolgus (cyno) TFPI K1 K2 (Table 1) was expressed in HEK293 cells and conditioned media was harvested 120 hours post transfection. Purified Cyno TFPI K1 K2 was incubated with human neutrophil elastase (HNE) at 1 :70 (molar ratio HNE FPI) for 120min at RT for cleavage to occur. Separation of cyno K1 from cyno K2 was performed using anion exchange chromatography on HQ50 (Poros). Size exclusion chromatography using Superdex 75 was performed as the final purification step. Endoproteinase AspN was used to trim the residual AviTag from the C-terminus of the cyno K2 domain.9. Generation of antibody Fab / cyno TFPI K2 complexes for structural studies

[249] Anti-TFPI antibodies 4D8.b1 , TFPI-23, TFPI-24, 2A8-200 (Table 3) and Mab 2974 (R&D systems) were digested with immobilized Papain per manufacturer's protocol (Thermo / Pierce). MabSelect SuRe was used to purify the Fabs from the digest, which were then used for complex formation with cyno TFPI K2. The Fab / cyno TFPI K2 complexes were then concentrated to approximately 16 mg / ml. The concentrated complexes were then used to screen for protein crystallization conditions.EXAMPLE 2. GENERATION OF MOUSE ANTI-TFPI ANTIBODIES1. Mouse immunization and hybridoma generation

[250] A cohort of five BALB / c mice were each immunized subcutaneously with a mixture of 5 ug humTFPI K1 K2 and 5 ug murTFPI K1 K2 protein emulsified in Complete Freund's Adjuvant. The mice were subsequently immunized twice per week with the protein mixture alternately emulsified in Incomplete Freund's Adjuvant or diluted in PBS. Blood samples were taken on day 17 and day 27 (after the fifth and seventh immunizations, respectively), and sera were tested for the presence of circulating anti-TFPI antibodies by ELISA. By day 27, each mouse received a final boost of protein mixture (10 ug) intraperitoneally. Four days later, draining lymph nodes (axillary, inguinal and popliteal) were harvested, and pooled lymph node cells were mixed at a 1 :1 ratio with the P3X63.Ag8.653 cells and subjected to electro-cell fusion. Fused cells were plated in RPMI1640 media supplemented with FBS (25%), NCTC-109 (12.5%), Glutamax (1 %), Penicillin-Streptomycin (1 %), Hybridoma Cloning Supplement (5%) and HAT (1 x 10"4M hypoxanthine, 4 x 10"7M aminopterin, and 1.6 x 10"5M thymidine). Fourteen days after the fusion hybridoma culture supernatants were tested for binding to humTFPI K1 K2 by ELISA. Based upon their binding activity and their efficacy in functional assays, antibodies from three hybridomas, 4D8, 6B7 and 7A4, were selected for further characterization.2. Cloning and sequencing of hybridoma-derived anti-TFPI antibodies

[251] RNA from hybridomas 4D8, 6B7 and 7A4 was prepared and the variable region DNA sequences from the expressed antibodies were obtained by RT-PCR cloning. The PCR products were cloned into the TOPO-TA cloning vector, then sequenced by conventional methods. One heavy chain and light chain cDNA pair was detected from hybridomas 6B7 and 7A4. Two heavy chain and light chain cDNAs were detected from 4D8.EXAMPLE 3. CHARACTERIZATION OF MOUSE HYBRIDOMA ANTI-TFPI ANTIBODIES

[252] Parental hybridomas 4D8, 6B7 and 7A4 were subcloned by limiting dilution to obtain monoclonal hybridoma cell lines. Positive subclones were identified by ELISA screening for reactivity with humTFPI K1 K2 and expanded. Purified antibodies from one subclone of each hybridoma were characterized further.1. TFPI binding

[253] Purified anti-TFPI antibodies 4D8.B1 , 6B7.C5 and 7A4.D9 were tested for binding to recombinant human and rabbit TFPI proteins by protein-binding ELISA. The EC50 values of each antibody for both humTFPI K1 K2-aviHis10 and rabTFPI K1 K2 are shown in Table 5.Table 5EC50 (nM) values of mouse anti-TFPI MAbs for human and rabbit TFPI

[254] Surface plasmon resonance experiments were carried out to assess the affinity of the purified mouse anti-TFPI antibodies for human and rabbit TFPI K1 K2 proteins. The ka, kd and KD values for each antibody binding to human and rabbit TFPI K1 K2 are shown in Table 6.Table 6Kinetic measurements for anti-TFPI mouse hybridoma clones binding to human and rabbit TFPI2. In vitro activity assays

[255] The anti-TFPI murine monoclonal antibodies were tested for activity in the FXa and TF-FXa- FVIIa inhibition reversal assays and the thrombin generation assay (TGA). The most potent antibody, 4D8.B1 , was chosen to move forward for further studies.Table 7Activity of anti-TFPI murine monoclonal antibodies in the FXa and TF-FXa-FVIIa inhibition reversal assays and the thrombin generation assay (TGA)Antibody FXa EC50 (nM) FXa-FVIIa EC50 (nM) TGA Velocity Index at 20 nM4D8.B1 5.9 6.67 26.36B7.C5 13.9 12.13 23.57A4.D9 22.3 9.35 23.3 EXAMPLE 4. GENERATION OF CHIMERIC AND HUMANIZED ANTIBODIES FROM CLONE 4D81. Generation of mouse human chimeric antibody 4D8

[256] Variable region cDNAs derived from hybridoma 4D8 were subcloned into mammalian expression vectors to generate chimeric antibodies in which the mouse heavy chain variable region was fused in frame to human lgG1 3M (SEQ 20, Table 4), and the mouse light chain variable region was fused in frame to the human Ig kappa constant region (SEQ 62, Table 4). The chimeric constructs were transiently transfected into HEK293 cells. To identify the correct heavy and light chain pair from hybridoma 4D8 a total of four transient transfections were carried out with all possible heavy and light chain combinations. Antibody generated from one of the transfections was termed hu-mu 4D8 chimera (Tables 3 and 4).2. Characterization of mouse-human chimeric antibody 4D8 (mu-hu 4D8)

[257] Mu-hu 4D8 chimera was tested for its ability to bind both human and rabbit TFPI K1 K2 proteins by protein binding ELISA (Table 8) and SPR (Table 9). The KD and EC50 values were closely comparable to those measured with purified mouse MAb 4D8.B1 , demonstrating that grafting of the mouse variable regions grafted onto the human lgG1 background retained binding activity.Table 8EC50 (nM) values of mu-hu 4D8 chimera for human and rabbit TFPITable 9Kinetic measurements for mu-hu 4D8 chimera binding to human and rabbit TFPI3. Humanization of hu-mu 4D8 chimera

[258] The hu-mu 4D8 chimera sequence was humanized by CDR grafting onto human acceptor framework sequences. DP54 framework and DPK9 framework were chosen. Combinations of the heavy and light chain constructs (see Table 3) were then expressed. The antibodies were tested for human and rabbit TFPI binding in an ELISA binding assay (Table 10) and human TFPI binding in an SPR binding assay (Table 11). Table 10EC50 (nM) values of humanized 4D8 antibodies binding to human and rabbit TFPI K1 K2 proteins

[259] Based upon these data, 4D8 Vk1 .1 x VH 1 .4 was selected for further characterization and designated hz4D8 (Table 3). The humanized anti-TFPI antibody (hz4D8) was compared with the murine 4D8. B1 for activity in the FXa inhibition reversal assay, the two-stage TF-FVI Ia-FX inhibition assay, and the thrombin generation assay. The data in Table 12 show that the humanized antibody had improved activity in all three assays compared with the mouse antibody, indicating that TFPI binding activity was fully retained in the humanized antibody.Table 12Comparison of 4D8.B1 and hz4D8 antibodies in the FXa and FXa-FVIIa inhibition reversal assays and the thrombin generation assay (TGA) Antibody FXa EC50 (nM) FXa-FVIIa EC50 (nM) TGA Velocity Index at 20 nM4D8.B1 4.15 3.5 13.5Hz4D8 1.87 1.57 15.7EXAMPLE 5. GENERATION OF ADDITIONAL ANTI-TFPI ANTIBODIES BY PHAGE DISPLAY1. Selection of Anti-TFPI Antibodies by Phage Display

[260] Single chain fragment variable (scFv) antibodies that bind to the recombinant human and mouse TFPI K1 K2 were identified following four rounds of selection using a phage display library of scFv antibody fragments derived from non-immunized human donors. Phage selections were performed in solution using streptavidin beads. Bound phage were eluted by incubation with 140mM triethanolamine (TEA) pH 1 1.5 or 50 mM MES pH 5.5 for 10 min at room temperature on a rotary shaker and neutralized with 1 M Tris-HCI, pH7.5.

[261] The eluted phage pool was used to infect 10 mL of an E. coli ER2738 culture that had been grown to mid-logarithmic phase (corresponding to an OD6oo of approximately 0.5). Bacteria were infected with phage for 30 minutes at 37°C without shaking, concentrated by centrifugation and plated, followed by overnight growth at 30°C. For the next round of selection, phages were rescued by inoculating 25 mL 2x TYAG / Tetracycline to an OD600 of ~ 0.1 , grown at 37°C to an OD600 of 0.3-0.5. Cells were super-infected with MK13K07 helper phage at 1 :20 cell / helper phage ratio, and incubated at 37°C without shaking for 30 minutes then shaking at 150 rpm for 60 minutes. The cells were then centrifuged and the pellet re-suspended in a kanamycin / non-glucose containing medium. This culture was grown overnight at 25°C. Phage were harvested in the supernatant following centrifugation and used in the next round of selection.2. Preparation of crude periplasmic material for use in ELISA assay.

[262] ScFv antibody fragments can be expressed either on the surface of a phage particle or in solution in the bacterial periplasmic space, depending upon the growth conditions used. To induce release of scFv antibody fragments into the periplasm, 96-deepwell plates containing 2X TY media with 0.1 % glucose / 100 μg / mL ampicillin were inoculated from thawed glycerol stocks and grown at 37°C for approximately 4 hours. The contents of the bacterial periplasm (peripreps) were released by osmotic shock. Plates were centrifuged and the scFv-containing supernatant was harvested.3. ELISA to measure binding of scFvs expressed in the periplasm to human and mouse TFPI K1 K2.

[263] A total of 1984 clones were picked randomly from rounds 2, 3 and 4 of all the branch selections. TFPI scFv binders were identified by the periplasmic preparation (periprep) binding ELISA. Biotinylated human and mouse TFPI K1 K2 were coated on 384-well Nunc Maxisorp streptavidin plates at a concentration of 1 μ9 / η"ΐΙ_ in PBS. The TFPI K1 K2 solutions were removed and plates were blocked for 1 hour at room temperature in 0.05%Tween 20 / 1 % BSA / PBS.Peripreps were prepared and blocked for 1 hour at room temperature in an equal volume of 6% milk / 1 % BSA. 20 μΙ / well of blocked periplasmic scFv and control antibodies were transferred to the appropriate plates and incubated for 1 hour at room temperature. A 1 :2,000 dilution of anti-myc horseradish peroxidase (HRP) or a 1 : 10,000 dilution of goat anti-human-HRP secondary antibody was added to detect bound scFv or anti-TFPI control antibodies. The signal was developed using 3,3',5,5'-Tetramethylbenzidine, with absorbance read at 450 nm on an Envision plate reader (Perkin Elmer). A total of 883 scFV clones were identified as TFPI binders. The 883 TFPI binding scFVs were sequenced to identify unique clones. 288 unique clones were chosen to test for TFPI / FXa competitive binding.4. ELISA to identify scFvs that compete with FXa binding to human and mouse TFPIK1 K2.

[264] A total of 288 unique clones were tested in an FXa / TFPI competitive binding ELISA. Human FXa was coated overnight on 384-well Nunc Maxisorp plates at a concentration of 1 μg / mL in PBS. The FXa solution was removed and the plate surface was blocked for 1 hour at room temperature in 0.05%Tween20 / 1 % BSA / PBS. Peripreps were prepared and blocked for 1 hour at room temperature in an equal volume of 6% milk / 1 % BSA. 20μΙ / ννβΙΙ of blocked periplasmic scFv and control antibodies were mixed with biotinylated humTFPI K1 K2 and allowed to incubate for 1 hour at room temperature. The mixture was transferred to the FXa coated plates and incubated for 1 hour at room temperature. A 1 :2000 dilution of streptavidin- horseradish peroxidase was added to detect bound TFPI. The signal was developed using 3,3',5,5'-Tetramethylbenzidine, with absorbance read at 450 nm on an Envision plate reader. A total of 48 scFV antibodies were classified as competitive inhibitors of TFPI / FXa binding.5. ScFv conversion to human IgG.

[265] A total of 48 ScFv antibodies with unique sequences that demonstrated binding to TFPI and inhibition in a TFPI / FXa competition ELISA were selected for sub-cloning into human lgG-3M cloning vectors. Briefly, fragments were amplified by standard PCR. The VH or VL fragments were gel purified and ligated into a mammalian expression vector containing either the human lgG1-3M (VH) or Kappa or Lambda constant region (VK / VL). The VH and VK / VL paired expression vectors were then used for transient mammalian expression and purification in HEK 293 cells.6. Characterization of human lgG-3M anti-TFPI antibodies

[266] 48 anti-TFPI antibodies were ranked in various assays including FXa and TF / FVIIa / FXa inhibition reversal assays. TFPI-3, TFPI-21 , TFPI-23, TFPI-24 and TFPI-26 had the desirable properties such as TFPI cross species, low or no binding to humTFPI2 K1 K2K3 (Table 13). The FXa and TF / FVIIa / FXa inhibition reversal assay data for these same 5 antibodies are shown in Table 14 and SPR binding data in Table 15.Table 13TFPI antibodies that showed binding to multiple TFPI species (human, monkey, murine, rabbit and rat) and no or weak binding to human TFPI2Table 14TFPI antibody activity in FXa, TF / FVIIa / FXa inhibition reversal and thrombin generation assaysTable 15TFPI antibody SPR binding kinetics to human and mouse TFPIAnalyte Ligand ka (1 / Ms) kd(1 / s) D (nM) humTFPI K1 K2 TFPI-3 6.25 x 104 1.7 x 10"3 27.05humTFPI K1 K2 TFPI-21 7.85 x 10s 3.47 x 10"2 43.95humTFPI K1 K2 TFPI-23 9.18 x 10s 9.71 x 10~3 9.89humTFPI K1 K2 TFPI-24 1.59 x 10s 8.62 x 10"4 5.46humTFPI K1 K2 TFPI-26 2.05 x 10s 1.18 x 10~3 5.79 murTFPI K1 K2 TFPI-3 2.15 x 10s 8.24 x 10"4 3.81murTFPI K1 K2 TFPI-21 1.73 x 10s 7.71 x 10~3 4.54murTFPI K1 K2 TFPI-23 1.69 x 10s 2.48 x 10~3 1.46murTFPI K1 K2 TFPI-24 2.48 x 10s 5.96 x 10~3 24.1murTFPI K1 K2 TFPI-26 1.29 x 10s 4.76 x 10"3 3.68EXAMPLE 6. EPITOPE MAPPING OF ANTI-TFPI ANTIBODIES BY SPR

[267] A sandwhich SPR assay was used to map the epitopes of the anti-TFPI antibodies discovered and disclosed in this document (TFPI-21 , TFPI-23, TFPI-24, 4D8, 6B7.c5 and 7A4.D9). Other known reference antibodies (hz4F36, 2A8-200 and Mab2974) were also inlcuded in the epitope mapping experiment. Antibody 1 was immobilized on a CM5 biacore chip using NHS chemistry. Human TFPI (humTFPI K1 K2) was initially injected onto the chip until binding was near apparent equilibrium. Immediately after stopping human TFPI injection, antibody 2 was injected over the chip. If antibody 2 binds the complex of antibody 1 and human TFPI on the surface of the CM5 chip, then antibody 2 has a distinct and non-overlapping TFPI binding epitope versus antibody 1 (scored as +). If antibody 2 shows no binding, then it is scored as as a significantly overlapping epitope (negative (-)) versus antibody 1. If antibody 2 shows weak binding then antibodies 1 and 2 are deemed to have some partial overlap in TFPI epitopes (scored as + / -). As shown in Table 16, TFPI-21 and TFPI-23 have similar epitopes and the data also show that TFPI-21 and TFPI-23 have epitopes that are completely distinct from mab2974 and hz4F36.Table 16Epitope mapping of anti-TFPI antibodies using an SPR sandwhich assayAntibody 1 was immobilized on the surface of a CM5 chip. Human TFPI (humTFPI K1 K2) was then injected onto the surface until the measurement was close to apparent equilibrium. Immediately after stopping TFPI injection, antibody 2 was injected to measure the binding to the antibody 1 TFPI complex. A "+" score is given to antibody 1 and 2 parings that have completely distinct epitopes. A "-" score is given to antibody pairings that have strongly overlapping epitopes. If antibody 2 shows weak binding then antibodies 1 and 2 are deemed to have some partial overlap in TFPI epitopes (scored as + / -). EXAMPLE 7. GERMLINING HUMAN FRAMEWORKS OF TFPI-23 ANTIBODY

[268] Two variants of TFPI-23 were made to increase the content of human framework germline residues. TFPI-106 containes H1 Q to E and H5V to L mutations (Kabat numbering) and TFPI-107 (Tables 3 and 4), contained H1 Q to E, H5V to L and H94I to K mutations (Kabat numbering). TFPI- 106, TFPI-107, and TFPI-23, were expressed, purified, and tested for binding to humTFPI K1 K2 by SPR. The data in Table 17 show that when compared to the TFPI-23 parental antibody, TFPI-106 germline variant retained full binding affinity.Table 17TFPI-23 human frameworks germline variants SPR binding kinetics to human TFPITFPI-106 showed a modest improvement in binding when compared to the parental TFPI-23 antibody. EXAMPLE 8. GERMLINING HUMAN FRAMEWORKS OF TFPI-24 ANTIBODY

[269] Four TFPI-24 VL variants were made (TFPI-1 10, TFPI-1 1 1 , TFPI-1 12, TFPI-1 13) and paired with the TFPI-24 VH sequence. Three TFPI-24 VH variants were made (TFPI-108, TFPI-109, TFPI- 114) were made and paired with the TFPI-24 VL sequence. Based on these data, the best VL variant, TFPI-1 13, and the best VH variant, TFPI-108 were paired to produce antibody TFPI-1 18. TFPI-1 18 and TFPI-24 were tested for binding to human TFPI by SPR and the results in Table 18 show comparable binding kinetics.Table 18The binding kenetics of TFPI-24 and human frameworks variant TFPI-118 to human TFPI were compared using SPRTFPI-118 showed comparable binding kinetics to the parental TFPI-23 antibody.EXAMPLE 9. SPR BINDING KINETICS OF ANTI-TFPI ANTIBODIES TO TFPI FROM VARIOUS SPECIES

[270] Anti-TFPI antibodies (TFPI-106, TFPI-1 18, and hz4F36) were analysed by SPR to determine the binding kinetics to TFPI from different animal species (human (huTFPI K1 K2), cynomolgus monkey (cynTFPI K1K2), rabbit (rabTFPI K1K2), mouse (murTFPI K1K2) and rat (ratTFPI K1K2); Tablel). Three comparitor antibodies (hz4F36, 2A8 and 2A8-200) were also included in this experiment.Table 19Anti-TFPI antibody SPR binding kinetics to human, cyno, rabbit, rat and mouse TFPI (The Kd values areAnalyte Ligand ka (1 / Ms) kd(1 / s) D (nM) humTFPI K1K2 TFPI-106 2.72 x10s 9.74 x 10"3 3.7humTFPI K1K2 TFPI-118 1.25 x10s 1.19x 10"3 9.61humTFPI K1K2 hz4D8 3.16x10s 1.32 x 10"3 0.42humTFPI K1K2 hz4F36 1.89 x10s 9.30 x 10"4 0.49humTFPI K1K2 2A8 3.55 x10s 3.77 x 10"3 10.6humTFPI K1K2 2A8-200 1.16x10s 3.81 x 10~3 0.327cynTFPI K1K2 TFPI-106 6.55 x10s 8.01 x 10~3 1.22cynTFPI K1K2 TFPI-118 7.21 x10s 1.27 x 10"3 1.8cynTFPI K1K2 hz4D8 2.93 x107 1.95 x 10"3 0.067cynTFPI K1K2 hz4F36 6.86 x10s 2.88 x 10"3 0.425cynTFPI K1K2 2A8 2.37 x10s 3.06 x 10"2 13.25cynTFPI K1K2 2A8-200 1.25 x10s 8.09 x 10"4 0.637rabTFPI K1K2 TFPI-106 3.66 x10s 1.55 x 10"2 4.25rabTFPI K1K2 TFPI-118 2.01 x10s 1.55 x 10"2 5.79rabTFPI K1K2 hz4D8 3.16x10s 2.9 x10"3 0.502rabTFPI K1K2 hz4F36 4.2 x 10s 7.6 x10"3 1.81rabTFPI K1K2 2A8 7.3 x 10s 1.23 x 10"3 1.69rabTFPI K1K2 2A8-200 1.92 x10s 2.77 x 10"4 0.145murTFPI K1K2 TFPI-106 4.05 x10s 2.32 x 10"3 0.575murTFPI K1K2 TFPI-118 2.19x10s 9.82 x 10~3 45.6murTFPI K1K2 hz4D8 - - No binding murTFPI K1K2 hz4F36 - - No binding murTFPI K1K2 2A8 1.91 x10s 6.32 x 10"3 33.65murTFPI K1K2 2A8-200 2.54 x10s 1.17x10"3 0.455ratTFPI K1K2 TFPI-106 3.01 x10s 4.71 x 10~3 1.57ratTFPI K1K2 TFPI-118 4.83 x10s 1.75 x 10"3 3.65ratTFPI K1K2 hz4D8 - - No binding ratTFPI K1K2 hz4F36 - - No binding ratTFPI K1 K2 2A8 - - Not testedratTFPI K1 K2 2A8-200 - - Not testedEXAMPLE 10. ANTI-TFPI ANTIBODY / TFPI COMPLEX STRUCTURES1. 4D8.b1 Fab / cyno TFPI K2 complex structure[271 ] The 4D8.b1 Fab and cyno TFPI K2 were mixed at a 1 : 1 molar ratio to form the complex. Final purification was performed using a Superdex 200 column. The complex was concentrated to 12.6 mg / ml for structural studies. Crystals of the TFPI K2+4D8 Fab complex were obtained in 100mM Tris-HCI pH8.5, 20% PEG10000. It yielded rod-shaped crystals that diffracted to 2.9 A. Crystals were transiently cry o- protected and synchrotron data collection was performed remotely atAdvanced Photon Source. Image frames were processed using software AutoPROC (Global Phasing Ltd). The data belongs to space group P212121 , with unit cells as follows: a = 62.102A, b = 82.284A, c = 103.628A, α = β = γ = 90°, with one complex per asymmetric unit. Molecular Replacement searches using homology models of 4D8 Fab as well as publicly available structures (RSCB Protein Data Bank; PDB codes 1 TFX and 4DTG) of TFPI K2 domains yielded convincing solutions of each component. Refinement was performed using software autoBUSTER (Global Phasing Ltd), and the final R / Rfree factors at 2.9A are 0.1707 and 0.2424, respectively, with RMSD of bond 0.01 OA, RMSD of angles 1.26°. Based on buried surface area (BSA) and percent BSA (%BSA) for residues at the Fab / TFPI K2 interface, the epitope and paratope of the 4D8 Fab were determined. The following residues in K2 domain of TFPI are involved in direct contact with 4D8 Fab (epitope according to BSA): E101 , P103, Y109, 11 10, T1 1 1 , Y1 13, F1 14, S1 19, Q121 . C122, E123, R124, F125, K126, and L140. The following residues in heavy chain of 4D8 Fab comprise the heavy chain paratope: D50, T57, L58, Y59, Q61 , K64, D98, Y99, and D100. The following residues in light chain of 4D8 Fab comprise the light chain paratope: H30, W50, H91 , Y92, T93, T94, P95, and Y96. The BSA and %BSA values for the epitope and paratope residues are shown in table 20.Table 20Anti-TFPI antibody 4D8.b1 epitope and paratope residues as defined by buried surface area (BSA) and percent BSA (%BSA) of the interface residues in the 4D8.b1 Fab / cyno TFPI K2 complex structure (Antibody light chain (LC) and heavy chain (HC) residues are numbered using Kabat definitions). A cutoff (BSA of 20 A2 or greater, or involved in electrostatic interaction) is applied in BSA analysis.Residue Chain Residue Classification BSA %BSA#GLU TFPIK2 101 epitope 33.93 48.73PRO TFPIK2 103 epitope 34.91 74.82TYR TFPIK2 109 epitope 71.54 55.15THR TFPIK2 111 epitope 41.72 66.65 SER TFPIK2 119 epitope 32.89 65.61GLN TFPIK2 121 epitope 67.99 86.51GLU TFPIK2 123 epitope 63.53 99.15ARG TFPIK2 124 epitope 147.09 97.31LYS TFPIK2 126 epitope 114.72 95.85LEU TFPIK2 140 epitope 41.62 60.14ASP 4D8.b1 HC 50 paratope 5.98 52.56THR 4D8.b1 HC 57 paratope 26.48 42.04LEU 4D8.b1 HC 58 paratope 72.95 93.41TYR 4D8.b1 HC 59 paratope 15.75 33.75GLN 4D8.b1 HC 61 paratope 59.14 45.41ASP 4D8.b1 HC 98 paratope 62.87 50.71TYR 4D8.b1 HC 99 paratope 44.28 59.06ASP 4D8.b1 HC 100 paratope 5.83 27.84HIS 4D8.b1 LC 30 paratope 53.18 56.60TRP 4D8.b1 LC 50 paratope 53.41 51.52TYR 4D8.b1 LC 92 paratope 97.99 96.61THR 4D8.b1 LC 93 paratope 39.89 73.42THR 4D8.b1 LC 94 paratope 48.00 95.74TYR 4D8.b1 LC 96 paratope 15.49 72.232. 2A8 & 2A8-200 Fab / cyno K1K2 complex structures

[272] The 2A8 Fab and cyno TFPI K1 K2 were mixed at a 1 :1 molar ratio to form the complex. Final purification was performed using a Superdex 200 column. The complex was concentrated to 10.8 mg / ml for structural studies. Crystals of the complex containing 2A8 Fab and TFPI K1 K2 were obtained in the following two conditions: (1) 100mM HEPES pH7.5, 12.5% PEG8000, which yielded needle-shaped crystals that diffracted to 3.0 A; (2) 100mM HEPES pH 7.5, 1600mM Ammonium Sulfate, 2% PEG 1000, which yielded block-shaped crystals that diffracted to 3.3 A. Crystals were transiently cry o- protected and synchrotron data collection was performed remotely at Advanced Photon Source. Image frames were processed using software AutoPROC (Global Phasing Ltd). The data belongs to space group P3221 , with unit cells as follows: a = b = 196.146A, c = 41.262A, α = β= 90°, Y = 120°, with one complex per asymmetric unit. Molecular Replacement searches using homology models of 2A8 Fab as well as publicly available structures (RSCB Protein Data Bank; PDB codes 1TFX and 4DTG) of TFPI K2 domains yielded convincing solutions of each component. Refinement was performed using software PHENIX, and the final R / Rfree factors at 3.0A are 0.1667 and 0.2088, respectively, with RMSD of bond 0.01 1 A, RMSD of angles 1.474°. Based on buried surface area (BSA) and percent BSA (%BSA) for residues at the Fab TFPI K1 K2 interface, the epitope and paratope of the complex were determined. The following residues in TFPI K1 K2 domains of TFPI are involved in direct contact with 2A8 Fab (epitope according to BSA): D31 , D32, G33, P34, C35, K36, E100, E101 , P103, G104, 1105, C106, R107, G108, Y109, E123, K126, Y127 and G128.The following residues in heavy chain of 4D8 Fab comprise the heavy chain paratope: G26, T28, S31 , Y32, Y96, R97, Y98, W99 and D101 (Kabat numbering). The following residues in the light chain of 2A8 Fab comprise the light chain paratope: L28, R29, N30, Y31 , Y32, Y49, Y50, D51 and N66 (Kabat numbering). The BSA and %BSA values for the epitope and paratope residues are shown in table 21. The very closely related antibody, 2A8-200, was also solved in complex with TFPI K1 K2 using essentially identical methods. The epitope and paratope of this antibody was identical to that of 2A8.Table 21Anti-TFPI antibody 2A8 epitope and paratope residues as defined by buried surface area (BSA) and percentBSA (%BSA) of the interface residues in the 2A8 Fab / cyno TFPI K2 complex structure(Antibody light chain (LC) and heavy chain (HC) residues are numbered using Kabat definitions). A cutoff (BSA of 20 A2 or greater, or involved in electrostatic interaction) is applied in BSA analysis.Residue Chain Residue Classification BSA %BSA#ASP TFPI K1 K2 31 epitope 41.9 59.8ASP TFPI K1 K2 32 epitope 4.9 44.0PRO TFPI K1 K2 34 epitope 98.8 88.7CYS TFPI K1 K2 35 epitope 40.5 91.8LYS TFPI K1 K2 36 epitope 143.6 73.4GLU TFPI K1 K2 100 epitope 47.6 35.6GLU TFPI K1 K2 101 epitope 90.2 90.7PRO TFPI K1 K2 103 epitope 56.8 79.2ILE TFPI K1 K2 105 epitope 9.3 39.1ARG TFPI K1 K2 107 epitope 1 11 .0 71.3GLY TFPI K1 K2 108 epitope 20.5 55.8TYR TFPI K1 K2 109 epitope 128.1 79.1GLU TFPI K1 K2 123 epitope 26.5 43.0LYS TFPI K1 K2 126 epitope 49.3 60.2TYR TFPI K1 K2 127 epitope 1.5 9.0GLY TFPI K1 K2 128 epitope 3.2 47.7GLY 2A8 HC 26 paratope 29.3 46.5THR 2A8 HC 28 paratope 61.6 74.1SER 2A8 HC 31 paratope 46.5 56.7TYR 2A8 HC 32 paratope 54.2 85.6TYR 2A8 HC 96 paratope 85.7 99.1ARG 2A8 HC 97 paratope 104.4 78.6TYR 2A8 HC 98 paratope 89.3 81.3TRP 2A8 HC 99 paratope 20.0 96.7ASP 2A8 HC 101 paratope 16.5 51.6LEU 2A8 LC 28 paratope 7.4 67.0ASN 2A8 LC 30 paratope 43.4 38.7 TYR 2A8 LC 31 paratope 49.6 58.2TYR 2A8 LC 32 paratope 94.8 72.8TYR 2A8 LC 49 paratope 43.0 79.4TYR 2A8 LC 50 paratope 41.2 92.9ASP 2A8 LC 51 paratope 15.7 64.43. Mab 2974 Fab / TFPI K2 complex structure

[273] The Mab 2974 (R&D Systems) Fab and cyno TFPI K2 were mixed at a 1 :1.2 molar ratio to form the complex. Final purification was performed using a Superdex 200 column. The complex was concentrated to 17.5 mg / ml for structural studies. Crystals of the complex containing Mab 2974 Fab and TFPI K2 were obtained in 100mM Sodium Citrate pH 5.6, 20% isopropanol, 20% PEG4000, which yielded block-shaped crystals that diffracted to 2.15 A. Crystals were transiently cryo-protected and synchrotron data collection was performed remotely at Advanced Photon Source. Image frames were processed using software AutoPROC (Global Phasing Ltd). The data of the complex belongs to space group P212121 , with unit cells as follows: a = 82.075A b = 117.829A, c = 170.945A, α = β = γ = 90°, with three complexes per asymmetric unit. Since the sequence of Mab 2947 Fab was not available, a high-resolution data set of the Fab alone (1.63A) was collected, along with bioinformatics analysis, to decipher the protein sequence. Molecular Replacement searches using the structure of Mab 2974 Fab as well as publicly available structures (RSCB Protein Data Bank; PDB codes 1TFX and 4DTG) of TFPI K2 domains yielded convincing solutions of each component. Refinement was performed using software autoBUSTER, and the final R / Rfree factors at 2.15A are 0.1702 and 0.2161 , respectively, with RMSD of bond 0.010A, RMSD of angles 1.13°. Based on buried surface area (BSA) and percent BSA (%BSA) for residues at the Fab TFPI K2 interface, the epitope of the complex was determined. The following residues in TFPI K2 domain of TFPI are involved in direct contact with Mab 2974 Fab (epitope according to BSA): E100, E101 , P103, R107, Y109, T11 1 , N1 16, Q1 18, S119, Q121 , E123, R124, F125 and K126. The BSA and %BSA values for the epitope residues are shown in table 22.Table 22Anti-TFPI antibody Mab 2974 epitope residues as defined by buried surface area (BSA) and percent BSA (%BSA) of the interface residues in the Mab 2974 Fab / cyno TFPI K2 complex structure. A cutoff (BSA of 20A2 or greater, or involved in electrostatic interaction) is applied in BSA analysis.Residue Chain Residue # Classification BSA %BSAGLU TFPI K2 100 epitope 25.9 16.8GLU TFPI K2 101 epitope 42.2 54.7PRO TFPI K2 103 epitope 26.8 58.5ARG TFPI K2 107 epitope 32.3 16.4 TYR TFPI K2 109 epitope 83.1 62.9THR TFPI K2 111 epitope 13.8 18.9ASN TFPI K2 116 epitope 23.9 71 .9GLN TFPI K2 118 epitope 107.0 62.7SER TFPI K2 119 epitope 48.4 87.6GLN TFPI K2 121 epitope 51 .6 53.3GLU TFPI K2 123 epitope 61 .6 79.8ARG TFPI K2 124 epitope 56.0 33.2LYS TFPI K2 126 epitope 1 14.8 91 .84. TFPI-23 Fab / cyno TFPI K2 complex structure

[274] The TFPI-23 Fab and cyno TFPI K2 were mixed at a 1 :2 molar ratio to form the complex. Final purification was performed using a Superdex 200 column. The complex was concentrated to 12.4 mg / ml for structural studies. Crystals of the TFPI K2+4D8 Fab complex were obtained in 100mM Bis-Tris pH6.5, 20% PEGMME5000. It yielded fiber-shaped crystals that diffracted to 2.9A. Crystals were transiently cryo- protected and synchrotron data collection was performed remotely at Advanced Photon Source. Image frames were processed using software AutoPROC (Global Phasing Ltd). The data belongs to space group P1 , with unit cells as follows: a = 74.669A, b = 101.372A, c = 1 19.275A, a= 101.83, β = 92.27°, γ = 96.78°, with six copies of complex per asymmetric unit. Molecular Replacement searches using homology models of TFPI-23 Fab as well as publicly available structures (RSCB Protein Data Bank; PDB codes 1TFX and 4DTG) of TFPI K2 domains yielded convincing solutions of each component. Refinement was performed using software autoBUSTER, and the final R / Rfree factors at 2.9A are 0.1961 and 0.2344, respectively, with RMSD of bond 0.01 OA, RMSD of angles 1.22°. Based on BSA and percent BSA (%BSA) for residues at the Fab TFPI K2 interface, the epitope and paratope of the complex were determined. The following residues in K2 domain of TFPI are involved in direct contact with the TFPI-23 Fab (epitope according to BSA): D102, 1105, C106, R107, G108, R1 12, Y127, G129, C130, L131 , G132, M134 and E138. The following residues in heavy chain of 4D8 Fab comprise the heavy chain paratope: A33, W47, A50, 151 , S52, S56, Y58, L95, G96, A97, T98, S99, L100 and S100A. The following residues in light chain of 4D8 Fab comprise the light chain paratope: A29, Y31 , Y91 , S95A, G95B and S95C. The BSA and %BSA values for the epitope and paratope residues are shown in table 23.Table 23Anti-TFPI antibody TFPI-23 epitope and paratope residues as defined by buried surface area (BSA) and percent BSA (%BSA) of the interface residues in the TFPI-23 Fab / cyno TFPI K2 complex structure (Antibody light chain (LC) and heavy chain (HC) residues are numbered using Kabat definitions). A cutoff (BSA of 20 A2 or greater, or involved in electrostatic interaction) is applied in BSA analysis. Residue Chain Residue # Classification BSA %BSAASP TFPI K2 102 epitope 27.4 49.2ILE TFPI K2 105 epitope 116.0 81 .9CYS TFPI K2 106 epitope 46.8 97.0ARG TFPI K2 107 epitope 99.9 49.5GLY TFPI K2 108 epitope 23.1 45.7ARG TFPI K2 112 epitope 42.8 70.4TYR TFPI K2 127 epitope 18.7 92.6GLY TFPI K2 129 epitope 36.7 69.5CYS TFPI K2 130 epitope 26.7 100.0LEU TFPI K2 131 epitope 120.8 97.5GLY TFPI K2 132 epitope 29.3 77.8MET TFPI K2 134 epitope 48.7 38.2GLU TFPI K2 138 epitope 43.8 31 .7ALA TFPI-23 HC 33 paratope 20.3 70.5TYR TFPI-23 HC 58 paratope 107.0 82.7LEU TFPI-23 HC 95 paratope 31 .6 93.4GLY TFPI-23 HC 96 paratope 20.8 73.1ALA TFPI-23 HC 97 paratope 12.1 34.0THR TFPI-23 HC 98 paratope 5.6 4.9SER TFPI-23 HC 99 paratope 2.4 80.7LEU TFPI-23 HC 100 paratope 87.0 55.9SER TFPI-23 HC 100A paratope 24.7 83.8ALA TFPI-23 LC 29 paratope 38.7 86.9TYR TFPI-23 LC 31 paratope 60.8 86.0TYR TFPI-23 LC 91 paratope 27.0 94.3SER TFPI-23 LC 95A paratope 71 .4 64.9GLY TFPI-23 LC 95B paratope 25.3 96.55. TFPI-24 Fab / cyno TFPI K2 complex structure

[275] The TFPI-24 Fab and cyno TFPI K2 were mixed at a 1 :2 molar ratio to form the complex. Final purification was performed using a Superdex 200 column. The complex was concentrated to 12.2 mg / ml for structural studies. Crystals of the TFPI K2 / TFPI-24 Fab complex were obtained in 20% PEG3350, 200mM Ammonium Nitrate. It yielded crystals that diffracted to 1.75A. Crystals were transiently cry o- protected and synchrotron data collection was performed remotely at Advanced Photon Source. Image frames were processed using software AutoPROC. The data belongs to space group P212121 , with unit cells as follows: a = 42.817A, b = 71.362A, c =148.729A, α = β = y = 90°, with one complex per asymmetric unit. Molecular Replacement searches using homology models of TFPI-24 Fab as well as publicly available structures (RSCB Protein Data Bank; PDB codes 1TFX and 4DTG) of TFPI K2 domains yielded convincing solutions of each component. Refinement was performed using software autoBUSTER, and the final R / Rfree factors at 1.75A are 0.1900 and 0.2269, respectively, with RMSD of bond 0.01 OA, RMSD of angles 1 .18°. Based on buried surface area (BSA) and percent BSA (%BSA) for residues at the Fab / TFPI PC- interface, the epitope and paratope of the complex were determined. The following residues in PC- domain of TFPI are involved in direct contact with the TFPI-24 Fab (epitope according to BSA): E100, E101 , D102, G104, 1105, C106, R107, G108, Y109, 11 10, G129, C130, L131 and G132. The following residues in heavy chain of TFPI-24 Fab comprise the heavy chain paratope: A33, Q35, W47, G50, 151 , S52, N53, R55, S56, I57, G58, F95, L96, H97, S99 and D101. The following residues in light chain of TFPI-24 Fab comprise the light chain paratope: M31 , Y32, H34, Y36, L46, R50, W91 and Y96. The BSA and %BSA values for the epitope and paratope residues are shown in table 24.Table 24Anti-TFPI antibody TFPI-24 epitope and paratope residues as defined by buried surface area (BSA) and percent BSA (%BSA) of the interface residues in the TFPI-24 Fab / cyno TFPI K2 complex structure (Antibody light chain (LC) and heavy chain (HC) residues are numbered using Kabat definitions). A cutoff (BSA of 20 A2 or greater, or involved in electrostatic interaction) is applied in BSA analysis.Residue Chain Residue # Classification BSA %BSAGLU TFPI K2 100 epitope 44.1 30.0GLU TFPI K2 101 epitope 12.3 13.7ASP TFPI K2 102 epitope 57.1 93.5GLY TFPI K2 104 epitope 22.0 84.1ILE TFPI K2 105 epitope 137.7 99.1CYS TFPI K2 106 epitope 45.2 91.5ARG TFPI K2 107 epitope 202.7 99.7GLY TFPI K2 108 epitope 33.1 79.3TYR TFPI K2 109 epitope 106.1 76.3CYS TFPI K2 130 epitope 25.1 83.9LEU TFPI K2 131 epitope 66.8 54.9GLY TFPI K2 132 epitope 4.7 14.4ALA TFPI-24 HC 33 paratope 33.1 74.0GLN TFPI-24 HC 35 paratope 14.3 95.5SER TFPI-24 HC 52 paratope 26.3 99.3ASN TFPI-24 HC 53 paratope 54.6 52.6ARG TFPI-24 HC 55 paratope 22.0 11.0SER TFPI-24 HC 56 paratope 68.7 93.5PHE TFPI-24 HC 95 paratope 47.2 92.9 LEU TFPI-24 HC 96 paratope 18.4 41.5HIS TFPI-24 HC 97 paratope 70.9 44.2SER TFPI-24 HC 99 paratope 1 .0 2.1ASP TFPI-24 HC 101 paratope 3.7 11.6MET TFPI-24 LC 31 paratope 30.9 46.0TYR TFPI-24 LC 32 paratope 23.3 22.5HIS TFPI-24 LC 34 paratope 23.7 85.2TYR TFPI-24 LC 36 paratope 4.3 96.5ARG TFPI-24 LC 50 paratope 62.5 60.1TRP TFPI-24 LC 91 paratope 58.3 85.6TYR TFPI-24 LC 96 paratope 43.2 78.56. Epitope analysis of hz4F36

[276] The structure of the hz4F36 fab in complex with the human TFPI K2 domain is available at the Protein Data Bank (PDB accession code 4DTG). Based on BSA and percent BSA (%BSA) of the interface residues in the hz4F36 / TFPI K2 complex structure the epitope residues were defined as shown in Table 25.Table 25Anti-TFPI antibody hz4F36 epitope residues as defined by buried surface area (BSA) and percent BSA (%BSA) of the interface residues in the hz4F36 Fab / cyno TFPI K2 complex structure (PDB accession code 4DTG). A cutoff (BSA of 20 A2 or greater, or involved in electrostatic interaction) is applied in BSA analysis.7. Comparison of anti-TFPI antibody epitopes

[277] The anti-TFPI antibody epitopes shown in Tables 20-25 are compared in Tables 26 and 27. Table 26 shows the epitopes of antibodies that are specific for the TFPI K2 domain. Table 27 includes 2 additional antibodies (2A8 and 2A8-200) that bind both K1 and K2 domains.Table 26Anti-TFPI antibody epitope residues based on the data in Tables 20, 22-25X denotes TFPI amino acid residues that are part of the epitope. X (bold) denotes novel epitope residues for antibodies disclosed in this invention. Note that TFPI-23 does not compete for binding TFPI with hz4F36, 4D8 or mab2974 but does compete with TFPI-24 for binding to TFPI. Antibodies 2A8 and 2A8-200 are not included in this table since they require both K1 & K2 domains for binding and do not bind K2 domain alone.Table 27A comparison of anti-TFPI antibody epitope residues based on the data shown in Tables 20-25Human TFPI residues TFPI domain TFPI-24 TFPI-23 4D8 hz4F36 R&D2974 2A8 2A8-200D31 K1 X XD32 K1 X XG33 K1P34 K1 X XC35 K1 X XK36 K1 X XC59 K1E100 K2 X X X X XE101 K2 X X X X X XD102 K2 X X XP103 K2 X X X X XG104 K2 X1105 K2 X X X XC106 K2 X XR107 K2 X X X X X XG108 K2 X X X XY109 K2 X X X X X X1110 K2T1 11 K2 X X XR1 12 K2 XY1 13 K2 XF114 K2Y1 15 K2N1 16 K2 X XN1 17 K2Q118 K2 X XS1 19 K2 X XK120 K2Q121 K2 X X XC122 K2E123 K2 X X XR124 K2 X X XF125 K2K126 K2 X X X X XY127 K2 X X XG128 K2 X XG129 K2 XC130 K2 X XL131 K2 X XG132 K2 X XN133 K2M134 K2 XN135 K2N136 K2F137 K2 E138 K2 XT139 K2L140 Κ2 X XE141 Κ2X denotes TFPI amino acid residues that are part of the epitope. X (bold) denotes novel epitope residues for antibodies disclosed in this invention. Antibodies 2A8 and 2A8-200 require both K1 & K2 domains for binding and do not bind K2 or K1 domain alone.Table 28Prediction of key TFPI epitope residues for TFPI-23 by alanine scanning using computational methods(Accelrys Discovery Studio 4.1)Based on an arbitrary threshold of >1 kcal / mol, 3 TFPI residues (Ile105, Arg107 and Leu131), when mutated to alanine, are predicted to contribute significantly to binding of TFPI-23 to TFPI.Table 29ATFPI-23 CDR and framework residues within 4 angstroms of the TFPI K2 epitopeUsing computational prediction methods (Accelrys Discovery Studio 4.1), possible amino acid substitutions are also shown for each CDR / paratope residue that are predicted to not negatively affect the stability of TFPI-23 or the affinity to TFPI ( < 0.5 kcal / mol, columns 4-6). These are categorized into three groups: (1) those with at least a neutral effect on binding ( < 0.5 kcal / mol affinity, col. 4), (2) those that have a neutral / stabilizing effect on binding ( < -0.5 kcal / mol affinity, col. 5) and (3) the top 3 predicted sites with the most stabilizing effect on affinity. Kabat numbering is used for all residues (col. 6). 138Glu / L93Ser and 131 Leu / L96Gly are included as optional contact residues because the distance marginally exceeds 4A (4.07 A and 4.03 A, respectively), but is close enough to be rounded to 4A.Table 29BTFPI epitope residues and corresponding TFPI-23 paratope residuesTable 29CTFPI epitope residues and corresponding TFPI-23 paratope residues by BSA (no cutoff of minimal BSA applied)EXAMPLE 11. DILUTE PROTHROMBIN TIME (DPT)

[278] The ability of the anti-TFPI antibodies to inhibit endogenous TFPI in human FVIII deficient plasma (Hemophilia A) was studied using a dilute prothrombin time (PT) assay. The dilute PT is a modified PT assay using diluted Tissue Factor (Innovin) to prolong the clotting time.

[279] For the dPT analysis in humanFVIII deficient plasma (George King Biomedical), the Innovin® reagent was diluted 1 :3000 in a dilution buffer (Imidazole 50 mM, sodium chloride 0.1 M, BSA 1 mg / mL, calcium chloride 8.34 mM, pH 7.4) and preincubated to 37°C. Plasma was thawed in a 37°C water bath for 5 minutes immediately before assay. Dilutions of anti-TFPI antibodies were prepared in PBS and added to plasma and the plasma was incubated for 20 minutes at room temperature. Following this incubation, 50 μL· of the plasma was incubated for 1 minute at 37°C and the clotting reaction was initiated immediately with the addition of 50 μL· of 1 :3000 dilution of Innovin® reagent warmed to 37°C. The time to clot was performed at 37°C using a STart®4 Coagulation Analyzer. Data points were collected in duplicate, entered into Microsoft excel and the Effective concentration (EC50) at 50% was estimated using GraphPad Prism®. The results are shown in ...

Claims

What is claimed is:

1. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to an epitope in Kunitz Domain 2 (K2) of Tissue Factor Pathway Inhibitor (TFPI), wherein said epitope comprises residues selected from the group consisting of:(a) residues Ile105, Arg107, and Leu131 , according to the numbering of SEQ ID NO:2;(b) residues Ile105, Arg107, Leu131 , and one or more residues selected from the group consisting of: Cys106, Gly 108, Cys130, and Gly132, according to the numbering of SEQ ID NO:2;(c) residues Ile105, Arg107, Leu131 , and one or more residues selected from the group consisting of: Asp102, Arg112, Tyr127, Gly129, Met134, and Glu138, according to the numbering of SEQ ID NO:2;(d) residues Ile105, Arg107, Leu131 , and one or more residues selected from the group consisting of: Cys106, Gly108, Cys130, and Gly 132, and further comprising one or more residues selected from the group consisting of: Asp102, Arg1 12, Tyr127, Gly129, Met134, and Glu138, according to the numbering of SEQ ID NO:2.

2. The antibody or antigen-binding fragment thereof of claim 1 , comprising the following heavy (H) chain and light (L) chain residues (numbering according to Kabat): H33 Ala, H58 Tyr, H95 Leu, H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu, H100A Ser, L29 Ala, L31 Tyr, L91 Tyr, L95A Ser, and L95B Gly.

3. The antibody or antigen-binding fragment thereof of claim 2, comprising the following residues (numbering according to Kabat):(a) H33 is Ala or Val;(b) H47 is Trp;(c) H50 is Ala;(d) H51 is lie;(e) H52 is Ser, Arg, Lys, Phe, or Tyr;(f) H56 is Ser, Arg, or Lys;(g) H58 is Tyr;(h) H95 is Leu;(i) H96 is Gly, Ala, Arg, Asn, Lys, Pro, Ser, or Val;(j) H97 is Ala;(k) H98 is Thr, His, lie, Leu, Met, Phe, or Tyr;(I) H99 is Ser;(m) H100 is Leu, Phe, Trp, or Tyr;(n) H100A is Ser, Arg, Asn, Gin, Glu His, Leu, Lys, Met, Phe, Pro, or Trp; (0) L29 is Ala;(p) L31 is Tyr;(q) L91 is Tyr;(r) L95A is Ser, Phe, Trp, or Tyr;(s) L95B is Gly; andt) L95C is Ser, Arg, Asn, Gin, Glu, lie, Leu, Lys, Met, Phe, Trp, Tyr, or Val;and optionally comprising the following residues: (u) L93 is Ser;(v) L96 is Gly.

4. An isolated antibody or antigen-binding fragment thereof that specifically binds the K2 of TFPI, wherein the antibody is selected from the group consisting of an antibody comprising:(a) a heavy chain variable region (VH) comprising a VH complementarity determining region one (CDR-H1) comprising the amino acid sequence of SEQ ID NO:38, a CDR-H2 comprising the amino acid sequence of SEQ ID NO:39, and a CDR-H3 comprising the amino acid sequence of SEQ ID NO:40;(b) a VH comprising the amino acid sequence of SEQ ID NO:41 ;(c) a VH comprising the amino acid sequence of SEQ ID NO:63;(d) a light chain variable region (VL) comprising a VL complementarity determining region one (CDR-L1) comprising the amino acid sequence of SEQ ID NO:33, a CDR-L2 comprising the amino acid sequence of SEQ ID NO:34, and a CDR-L3 comprising the amino acid sequence of SEQ ID NO:35;(e) a VL comprising the amino acid sequence of SEQ ID NO:36;(f) a heavy chain constant region (CH) that comprises the amino acid sequence of SEQ IDNO:20;(g) a light chain constant region (CL) that comprises the amino acid sequence of SEQ IDNO:26;(h) a heavy chain that comprises the amino acid sequence of SEQ ID NO:64;(1) a heavy chain that comprises the amino acid sequence of SEQ ID NO:42;(j) a light chain that comprises the amino acid sequence of SEQ ID NO:37;(k) a CDR-H1 comprising the amino acid sequence of SEQ ID NO:48, a CDR-H2 comprising the amino acid sequence of SEQ ID NO:49 and a CDR-H3 comprising the amino acid sequence of SEQ ID NO:50; (I) a VL comprising a CDR-L1 comprising the amino acid sequence of SEQ ID NO:43, a CDR-L2 comprising the amino acid sequence of SEQ ID NO:44, and a CDR-L3 comprising the amino acid sequence of SEQ ID NO:45;(m) a VH comprising a CDR-H1 comprising the amino acid sequence of SEQ ID NO:38, a CDR-H2 comprising the amino acid sequence of SEQ ID NO:39, and a CDR-H3 comprising the amino acid sequence of SEQ ID NO:40, and a VL comprising a CDR-L1 comprising the amino acid sequence of SEQ ID NO:33, a CDR-L2 comprising the amino acid sequence of SEQ ID NO:34, and a CDR-L3 comprising the amino acid sequence of SEQ ID NO:35;(n) a VH comprising the amino acid sequence of SEQ ID NO:63 and a VL comprising the amino acid sequence of SEQ ID NO:36; and(o) a heavy chain consisting of the amino acid sequence of SEQ ID NO:64 and a light chain consisting of the amino acid sequence of SEQ ID NO:37.

5. The antibody or antigen-binding fragment thereof of claim 1 , wherein said epitope further comprises one or more residues selected from the group consisting of: Glu100, Glu101 , Asp102, Gly 104, and Tyr109, according to the numbering of SEQ ID NO:

26. An isolated antibody, or antigen-binding fragment thereof, that specifically binds to a K2 of TFPI, wherein said epitope comprises residues Glu101 , Pro103, Tyr109, Thr1 11 , Ser1 19, Gln121 , Glu123, Arg124, Lys126, and Leu140, according to the numbering of SEQ ID NO: 2.

7. The antibody, or antigen-binding fragment thereof, of claim 6, comprising(a) a VH comprising a CDR-H1 comprising the amino acid sequence of SEQ ID NO: 87, a CDR-H2 comprising the amino acid sequence of SEQ ID NO: 88, and a CDR-H3 comprising the amino acid sequence of SEQ ID NO: 89; and(b) a VL comprising a CDR-L1 comprising the amino acid sequence of SEQ ID NO: 81 , a CDR-L2 comprising the amino acid sequence of SEQ ID NO: 82 and a CDR-L3 comprising the amino acid sequence of SEQ ID NO: 83;8. The antibody, or antigen-binding fragment thereof, of claim 1 , wherein said antibody is selected from the group consisting of:(a) an antibody comprising at least one paratope residue (numbering according to Kabat) that is within 4.0 A of at least one epitope residue on TFPI (numbering according to SEQ ID NO:2), as follows: epitope residue 102 Asp is within 4.0 A of paratope residue H58 Tyr; epitope residue 104 Gly is within 4.0 A of paratope residue H58 Tyr; epitope residue 105 lie is within 4.0 A of paratope residues H33 Ala, H50 Ala, H51 lie, H52 Ser, H56 Ser, H58 Tyr, H95 Leu; epitope residue 106 Cys is within 4.0 A of paratope residues H100 Leu, H100A Ser; epitope residue 107 Arg is within 4.0 A of paratope residue H96 Gly, H97 Ala, H98 Thr, H99 Ser, H100 Leu; epitope residue 108 Gly is within 4.0 A of paratope residue H100 Leu; epitope residue 1 12 Arg is within 4.0 A of paratope residue L29 Ala, L31 Tyr; epitope residue 127 Tyr is within 4.0 A of paratope residue L31 Tyr; epitope residue 129 Gly is within 4.0 A of paratope residue L31 Tyr; epitope residue 130 Cys is within 4.0 A of paratope residue L91 Tyr, L95B Gly; epitope residue 131 Leu is within 4.0 A of paratope residue H47 Trp, H50 Ala, H58 Tyr, L95A Ser, L95B Gly, L95C Ser; epitope residue 132 Gly is within 4.0 A of paratope residue H58 Tyr, L95A Ser; H58 Tyr, L95A Ser; epitope residue 134 Met is within 4.0 A of paratope residue L95A Ser; and epitope residue 138 Glu is within 4.0 A of paratope residue L29 Ala;(b) comprises at least one paratope residue (numbering according to Kabat) which can form a hydrogen bond with an epitope residue of TFIP (numbering according to SEQ ID NO:2) as follows: epitope residue 102 Asp can form a hydrogen bond with paratope residue H58 Tyr; epitope residue 107 Arg can form a hydrogen bond with at least one paratope residue selected from the group consisting of H96 Gly, H97 Ala, H98 Thr, H99 Ser, and H100 Leu; epitope residue 1 12 Arg can form a hydrogen bond with paratope residue L29 Ala; epitope residue 127 Tyr can form a hydrogen bond with paratope residue L31 Tyr; and epitope residue 131 Leu can form a hydrogen bond with paratope residue L95B Gly; and(c) an antibody comprising at least one paratope residue (numbering according to Kabat) which comprises a non-zero change in buried surface area due to interaction with an epitope residue (numbering according to SEQ ID NO:2) as follows: epitope residue 102 Asp interacts with paratope residue H58 Tyr; epitope residue 104 Gly interacts with paratope residue H58 Tyr; epitope residue 105 lie interacts with at least one paratope residue selected from the group consisting of H33 Ala, H34 Met, H50 Ala, H51 lie, H52 Ser, H56 Ser, H58 Tyr, and H95 Leu; epitope residue 106 Cys interacts with at least one paratope residue selected from the group consisting of H95 Leu, H100 Leu, H100A Ser, and L91 Tyr; epitope residue 107 Arg interacts with at least one paratope residue selected from the group consisting of H96 Gly, H97 Ala, H98 Thr, H99 Ser, and H100 Leu; epitope residue 108 Gly interacts with paratope residue H100 Leu; epitope residue 1 12 Arg interacts with at least one paratope residue selected from the group consisting of L29 Ala, L31 Tyr, and L93 Ser; epitope residue 127 Tyr interacts with at least one paratope residue selected from the group consisting of L31 Tyr, and L95B Gly; epitope residue 129 Gly interacts with at least one paratope residue selected from the group consisting of H100A Ser, L31 Tyr, and L91 Tyr; epitope residue 130 Cys interacts with at least one paratope residue selected from the group consisting of H95 Leu, H100A Ser, L31 Tyr, L91 Tyr, and L95B Gly; epitope residue 131 Leu interacts with at least one paratope residue selected from the group consisting of H47 Trp, H50 Ala, H58 Tyr, H95 Leu, L31 Tyr, L91 Tyr, L95A Ser, L95B Gly, L95C Ser, and L96 Gly; epitope residue 132 Gly interacts with at least one paratope residue selected from the group consisting of H58 Tyr, and L95A Ser; epitope residue 133 Asn interacts with paratope residue L95A Ser; epitope residue 134 Met interacts with at least one paratope residue selected from the group consisting of L93 Ser, L94 Ser, and L95A Ser; and epitope residue 138 Glu interacts with at least one paratope residue selected from the group consisting of L28 Gly, L29 Ala, and L93 Ser.

9. An isolated monoclonal antibody that competes for binding to TFPI and / or binds the same epitope as an antibody, or antigen-binding fragment thereof, of claim 4.

10. The antibody, or antigen-binding fragment thereof, of claim 1 , wherein said antibody, or antigen-binding fragment thereof, binds to TFPI with a binding affinity (Kd) value of from about 1x10" 8 M to about 1x10"10 M.

11. The antibody or antigen-binding fragment thereof of claim 1 (a), wherein said antibody or antigen-binding fragment thereof: (i) decreases clotting time as measured in a plasma based dilute prothrombin time assay; (ii) reduces clotting time in whole blood as measured bythromboelastrography; (iii) increases thrombin generation; (iv) increases FXa activity in the presence of TFPI; (v) enhances platelet accumulation in the presence of TFPI; (vi) increases fibrin generation in the presence of TFPI; or (vii) any combination thereof.

12. The antibody or antigen-binding fragment thereof of claim 11 , wherein said plasma or whole blood is deficient in Factor VIII or Factor IX.

13. An isolated nucleic acid molecule comprising a nucleotide sequence encoding the antibody or antigen-binding fragment thereof of claim 1.

14. An isolated nucleic acid molecule comprising a nucleotide sequence encoding the antibody of claim 4.

15. The nucleic acid of claim 14, wherein the nucleotide sequence encodes a VH comprising a CDR-H1 comprising the amino acid sequence of SEQ ID NO:38, a CDR-H2 comprising the amino acid sequence of SEQ ID NO:39, and a CDR-H3 comprising the amino acid sequence of SEQ ID NO:40, and a VL comprising a CDR-L1 comprising the amino acid sequence of SEQ ID NO:33, a CDR-L2 comprising the amino acid sequence of SEQ ID NO:34, and a CDR-L3 comprising the amino acid sequence of SEQ ID NO:35.

16. The nucleic acid of claim 15, wherein the nucleotide sequence encodes a VH comprising the amino acid sequence of SEQ ID NO:63 and a VL comprising the amino acid sequence of SEQ ID NO:36.

17. The nucleic acid molecule 14, comprising a nucleotide sequence selected from the group consisting of:(a) the sequence of SEQ ID NO:175;(b) the sequence of SEQ ID NO:176;(c) the sequence of SEQ ID NO: 177;(d) the sequence of SEQ ID NO:178;(e) the sequence of the insert present in the plasmid deposited under ATCC Accession No. PTA-122328; and(f) the sequence of the insert present in the plasmid deposited under ATCC Accession No. PTA-122329.

18. A pharmaceutical composition comprising an antibody or antigen-binding fragment thereof of claim 1 , and a pharmaceutically acceptable carrier or excipient19. A method of reducing the activity of Tissue Factor Pathway Inhibitor (TFPI), comprising administering to a subject in need thereof a therapeutically effective amount of the antibody or antigen-binding fragment thereof of claim 1.

20. A method of reducing the activity of Tissue Factor Pathway Inhibitor (TFPI), comprising administering to a subject in need thereof a therapeutically effective amount of the antibody or antigen-binding fragment thereof of claim 4(m) or 4(n).

21. The method of claim 19, said method comprising administering the antibody of claim 7.

22. A method of shortening bleeding time, comprising administering to a subject in need thereof a therapeutically effective amount of the antibody or antigen-binding fragment thereof of claim 1.

23. A method of shortening bleeding time, comprising administering to a subject in need thereof a therapeutically effective amount of the antibody or antigen-binding fragment thereof of claim 4(m) or 4(n).

24. The method of claim 22, said method comprising administering the antibody of claim 7.

25. The method of claim 22, wherein said subject suffers from or is susceptible to hemophilia A, hemophilia B, von Willebrand Disease (vWD), or a platelet disorder.

26. The method of claim 23, wherein said subject suffers from or is susceptible to hemophilia A, hemophilia B, von Willebrand Disease (vWD), or a platelet disorder.

27. The method of claim 19, further comprising administering a therapeutically effective amount of FVIIa.

28. The method of claim 20, further comprising administering a therapeutically effective amount of FVIIa.

29. A method of shortening bleeding time in a subject in need thereof, said method comprising administering a therapeutically effective amount of the antibody of claim 1 , or antigen-binding fragment thereof, and a clotting agent.

30. The method of claim 29, wherein said subject suffers from or is susceptible to hemophilia A or hemophilia B and said clotting agent is selected from the group consisting of factor Vila, factor VIII, factor IX and tranexamic acid.

31. The method of claim 30, said method comprising administering the antibody, or antigen- binding fragment thereof, of claim 4(m) or 4(n).