Approaches for the selective depletion of adamts13-specific antibodies

Abstract

The present disclosure includes a fusion protein or molecule, called a "Macromolecule that depletes ADAMTS13-specific antibodies'; including a targeting component that specifically binds to a cell surface receptor or other cell surface molecule, and an antigen component fused directly or indirectly to the targeting component. The antigen component is configured to specifically bind target antigen-specific antibodies. The present disclosure also includes a method of depleting target antigen-specific antibodies from a patient by treating the patient with a macromolecule that targets ADAMTS13-specific antibodies having an antigen component configured to specifically bind the target antigen-specific antibodies.

Description

[0001] APPROACHES FOR THE SELECTIVE DEPLETION OF ADAMTS13-SPECIFIC ANTIBODIES

[0002] CROSS REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Application No. 63 / 697,234 which is hereby incorporated by reference herein in its entirety.

[0004] REFERENCE TO SEQUENCE LISTING SUBMITTED ELECTRONICALLY

[0005] This application contains a Sequence Listing, which is submitted electronically via EFS-Web as an XML Document formatted sequence listing with a file name Seldeg_TTP_ST26.xml having a creation date of 19 September 2025 and having a size of 160 Kb. The sequence listing submitted via EFS-Web is part of the specification and is herein incorporated by reference in its entirety.

[0006] TECHNICAL FIELD

[0007] This disclosure relates to molecules that selectively deplete antigen-specific antibodies from the body. The antigen-specific antibodies bind to adisintegrin and metalloproteinase with thrombospondin motifs 13 (ADAMTS13).

[0008] BACKGROUND

[0009] Antibodies are Y -shaped proteins present in blood and other body fluids of the human body and the bodies of mammals. Antibodies are a critical component of the body’s immune system. They function by recognizing a unique part of a foreign target, called the antigen. An antibody is able to selectively recognize and trigger an immune response to an antigen through its two antigen-binding sites. Each antigen-binding site is at the end of each upper tip of the antibody’s Y-shape. The target antigen may bind one or both antigen-binding sites. The base of an antibody’s Y-shape is called an Fc fragment. When an antibody binds to its target, the Fc region can bring about target clearance through antibody effector functions. Such responses can include cellular processes to destroy the antigen. In certain autoimmune diseases and other illnesses, pathogenic antibodies may be created that target self-antigens in the body, contributing to pathogenesis. An antibody may be in either of two physical forms, a soluble form that is secreted from the cell and is free in the blood plasma, or a membrane-bound form that is attached to the outer-membrane of a B cell. The secreted antibodies cause pathology7in diseases involving autoreactive antibodies. They can also contribute to transplant rejection or the elimination of protein-based therapeutics.

[0010] SUMMARY

[0011] ADAMTS13 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs 13) is a plasma metalloprotease that plays a fundamental role in hemostasis by cleaving ultra-large von Willebrand factor (VWF) multimers. Under normal physiological conditions, AD AMTS 13 regulates the size and activity of VWF multimers, preventing excessive platelet aggregation and maintaining proper blood flow. The enzyme cleaves VWF at a specific site within the A2 domain, reducing the adhesive properties of VWF and preventing the formation of pathological microthrombi.

[0012] The structure of ADAMTS13 consists of multiple functional domains, including a metalloprotease domain, a disintegrin-like domain, a thrombospondin type 1 repeat, a cysteine- rich domain, a spacer domain, additional thrombospondin type 1 repeats, and two complement Clr / Cls, Uegf, Bmpl (CUB) domains. Each domain contributes to the enzy me's function, with some domains involved in substrate recognition and binding, while others participate in enzymatic activity and regulation.

[0013] Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare but lifethreatening hematological disorder characterized by the presence of autoantibodies directed against ADAMTS13. These autoantibodies inhibit ADAMTS13 activity and accelerate its clearance from the circulation, leading to severe ADAMTS13 deficiency. The resulting accumulation of ultra-large VWF multimers promotes widespread microvascular thrombosis, causing the characteristic clinical features of iTTP including thrombocytopenia, microangiopathic hemolytic anemia, and organ dysfunction affecting the brain, kidneys, heart, and other organs.

[0014] The pathogenesis of iTTP involves the production of polyclonal autoantibodies that recognize various epitopes on AD AMTS 13, with the spacer domain being the most frequently targeted region. These antibodies can interfere with ADAMTS13 function through multiple mechanisms, including direct inhibition of enzymatic activity, prevention of substrate binding, and enhancement of ADAMTS13 clearance from the plasma. iTTP requires a treatment that has a rapid mechanism of action to avoid severe disease that can lead to death. Current therapeutic approaches for iTTP include plasma exchange, immunosuppressive therapy, and rituximab treatment. While these interventions can be effective, they often require intensive medical management and may be associated with complications. Plasma exchange, the standard of care, removes both the pathogenic antibodies and replaces AD AMTS 13 activity through donor plasma, but this approach is non-specific and also removes other plasma components. Immunosuppressive therapies can reduce antibody production but may compromise the patient's immune system more broadly.

[0015] The development of more targeted therapeutic approaches that specifically target the pathogenic ADAMTS 13 autoantibodies while preserving other immune functions represents an area of ongoing research interest. Such approaches could potentially offer improved efficacy and reduced side effects compared to current non-specific treatments.

[0016] The present disclosure includes fusion proteins, herein referred to as macromolecules that target ADAMTS13-specific antibodies, that are configured to allow selective and rapid clearance of ADAMTS 13 -specific antibodies that cause disease in immune-mediated thrombotic thrombocytopenic purpura (iTTP). Macromolecules that target ADAMTS 13- specific antibodies provide a potential treatment that removes the disease-causing antibodies and also has a fast onset of action.

[0017] A macromolecule that targets ADAMTS 13-specific antibodies includes a targeting component that is configured to specifically bind to a cell surface receptor or other cell surface molecule, and an antigen component that is configured to specifically bind to an ADAMTS 13- specific antibody or a variant thereof.

[0018] The targeting component of the macromolecule that targets ADAMTS 13-specific antibodies may comprise a protein, a protein fragment, a carbohydrate, a carbohydrate derivative or a small molecule that is configured to specifically bind to a cell surface receptor or other cell surface molecule. The antigen component of the macromolecule that targets ADAMTS 13-specific antibodies may comprise one or more molecules of an antigen or antigen fragment or antigen mimetic configured to specifically bind antibodies that recognize ADAMTS 13 or domains thereof. Specifically, the antigen component of the macromolecule that targets ADAMTS 13 -specific antibodies may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic. The antigen component is fused directly or indirectly to the targeting component.

[0019] ADAMTS 13 comprises a metalloprotease (M), a disintegrin-like (D) domain, a first thrombospondin ty pe 1 (TSP1) repeat (T), Cys-rich (C) and spacer (S) domains (collectively known as MDTCS), TSP1 2-8 (T2-T8), CUB1 and CUB2 domains. The current invention describes novel configurations of macromolecules that target ADAMTS 13-specific antibodies and comprise the S domain. The S domain is recognized by autoantibodies in the majority of iTTP patients, and in the present invention, macromolecules comprising the S domain of ADAMTS13 are expressed using novel recombinant protein designs and are effective in capturing ADAMTS 13 -specific antibodies in plasma samples from patients with iTTP.

[0020] The M and D domains of ADAMTS 13 have enzymatic function and increase binding of this metalloprotease to VWF, respectively (Petri, A., Kim, H.J., Xu, Y., de Groot, R., Li, C., Vandenbulcke. A.. Vanhoorelbeke, K., Emsley, J.. Crawley. J.T.B. (2019) Crystal structure and substrate-induced activation of ADAMTS13. Nature Comms. 10, 3871). To reduce binding of macromolecules that target ADAMTS 13 -specific antibodies to VWF, in some embodiments, these domains are not included in the molecular design. Reduced binding of the macromolecule to VWF may be desirable to minimize possible effects, such as inhibition, of the macromolecule on endogenous ADAMTS 13-mediated cleavage of VWF. In the present invention, a novel fusion protein comprising T, C and S domains of ADAMTS 13 fused to a targeting component to generate a macromolecule that targets ADAMTS 13-specific antibodies is recombinantly produced. In a comparison with macromolecules comprising the D. T, C and S domains, this macromolecule has similar binding behavior to ADAMTS 13 -specific antibodies whilst having substantially reduced binding to VWF.

[0021] In one embodiment, the antigen component of the macromolecule comprises at least part of the S domain of ADAMTS 13.

[0022] In a further embodiment, the antigen component of the macromolecule comprises at least part of the C and S domains of ADAMTS 13.

[0023] In a further embodiment, the antigen component of the macromolecule comprises at least part of the T, C and S domains of ADAMTS 13.

[0024] In a further embodiment, the antigen component of the macromolecule comprises the entirety of at least one of the T, C and / or S domains of ADAMTS 13.

[0025] In a further embodiment, the antigen component of the macromolecule comprises substantially the entirety of each of said domains.

[0026] The antigen component may comprise a single polypeptide component comprising the foregoing domains. Alternatively, the antigen component may comprise two separate polypeptides, which may comprise the same or different domains of ADAMTS 13.

[0027] In a further embodiment, the domains may be comprised in three or more separate polypeptides of the antigen component. In one embodiment, the M domain polypeptide, which is comprised in the antigen component of the macromolecule, comprises the sequence of SEQ ID NO: 6, SEQ ID NO: 16, SEQ ID NO: 30, SEQ ID NO: 34, SEQ ID NO: 36, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 52, SEQ ID NO: 56, or SEQ ID NO. 58.

[0028] In one embodiment, the D domain polypeptide, which is comprised in the antigen component of the macromolecule, comprises the sequence of SEQ ID NO: 4, SEQ ID NO: 5. SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 30, SEQ ID NO: 34, SEQ ID NO: 36, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 52, SEQ ID NO: 55, SEQ ID NO: 56, or SEQ ID NO: 58.

[0029] In one embodiment, the T domain polypeptide, which is comprised in the antigen component of the macromolecule, comprises the sequence of SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17. SEQ ID NO: 18, SEQ ID NO: 21. SEQ ID NO: 27, SEQ ID NO: 29. SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 36, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52. SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56. or SEQ ID NO: 58.

[0030] In one embodiment, the C domain polypeptide, which is comprised in the antigen component of the macromolecule, comprises the sequence of SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12. SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17. SEQ ID NO: 18, SEQ ID NO: 21. SEQ ID NO: 27, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49. SEQ ID NO: 50. SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 54. SEQ ID NO: 55. SEQ ID NO: 56, SEQ ID NO: 58, or SEQ ID NO: 59.

[0031] In one embodiment, the S domain polypeptide, which is comprised in the antigen component of the macromolecule, comprises the sequence of SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12. SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17. SEQ ID NO: 18, SEQ ID NO: 21. SEQ ID NO: 27, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39. SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 58, or SEQ ID NO: 59.

[0032] In one embodiment, the CUB1 domain polypeptide, which is comprised in the antigen component of the macromolecule, comprises the sequence of SEQ ID NO: 7. SEQ ID NO: 24. SEQ ID NO: 25, SEQ ID NO: 30, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 53, SEQ ID NO: 57, or SEQ ID NO: 58.

[0033] In one embodiment, the CUB2 domain polypeptide, which is comprised in the antigen component of the macromolecule, comprises the sequence of SEQ ID NO: 7, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 30, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 53, SEQ ID NO: 57, or SEQ ID NO: 58.

[0034] The present disclosure also includes a method of depleting a target antigen-specific antibody from a patient by administering to the patient a macromolecule that targets ADAMTS13-specific antibodies in an amount sufficient to remove at least 50% of the target antigen-specific antibody from the circulation or a tissue or organ in the patient.

[0035] The macromolecule that targets ADAMTS 13 -specific antibodies and methods may further include the following details, which may be combined with one another unless clearly mutually exclusive: i) the targeting component can bind to the internalizing cell surface receptor or internalizing cell surface molecule with a dissociation constant of less than 10 uM at near-neutral pH; ii) near-neutral pH may be greater than 6.8 and less than 7.5; iii) the macromolecule that targets ADAMTS 13 -specific antibodies can comprise at least a first targeting component and a second targeting component, wherein the protein or protein fragment or molecule of the first targeting component is configured to bind to a different cell surface receptor or a different cell surface molecule than the protein or protein fragment or molecule of the second targeting component; iv) the targeting component may include a heterodimer of two immunoglobulin Fc fragments in which one immunoglobulin Fc fragment of the heterodimer is fused to the antigen component and the other immunoglobulin Fc fragment may not be, or both Fc fragments may be fused to the same or different antigen components; v) the macromolecule that targets ADAMTS 13-specific antibodies may have substantially reduced binding or no detectable binding to Fc gamma receptors; vi) at least one of the immunoglobulin Fc fragments can be derived from an immunoglobulin class or isotype that does not bind to Fc gamma receptors or complement; vii) at least one of the immunoglobulin Fc fragments can be configured to bind to Fc gamma receptors, particularly to FcyRIIb ; viii) at least one of the immunoglobulin Fc fragments can be modified to have a higher binding affinity for FcRn at near-neutral pH than an unmodified immunoglobulin Fc fragment; ix) the antigen component may be fused to one immunoglobulin Fc fragment at an N-terminus or a C-terminus of a hinge-CH2-CH3 domain of the immunoglobulin Fc fragment; x) the immunoglobulin Fc fragments may be modified to have no binding affinity for Fc gamma receptors and / or complement (Clq). or lower binding affinity for Fc gamma receptors and / or complement (Clq) than unmodified immunoglobulin Fc fragments; xi) the targeting component may comprise an immunoglobulin Fc fragment that is modified to bind with increased affinity to the inhibitory Fc gamma receptor, FcyRIIb; xii) the targeting component may include one or more antibody variable regions or fragments thereof that are configured to specifically bind to the internalizing cell surface receptor or the internalizing cell surface molecule; xiii) the antibody variable region or fragment thereof may include at least one nanobody; xiv) the nanobody may be a nanobody multimer in which one nanobody is fused to the antigen component and all other nanobodies in the nanobody multimer may not be fused to the antigen component; xv) the targeting component may dissociate from its target in early or late endosomes; xvi) the antigen component may be fused to an N-terminal location or a C- terminal location on the targeting component; xvii) the antigen component may be fused to a non-terminal location on the targeting component; xviii) the antigen component may be fused to the targeting component via a chemical reaction, through a linker, or during formation of a single combined antigen component-targeting component fusion protein; xix) the targeting component can be one or more albumin molecules, albumin fragments or mutated albumin variants that are configured to specifically bind to FcRn; xx) the targeting component can include one or more antibody variable domains or nanobodies that are configured to bind to a transferrin receptor; xxi) the targeting component can include one or more protein molecules or protein domains configured to bind to a transferrin receptor; xxii) the targeting component can include one or more antibody variable domains or nanobodies that are configured to bind to the asialoglycoprotein receptor (ASGPR); xxiii) the targeting component can include one or more protein molecules or protein domains, carbohydrates, carbohydrate derivatives or small molecules configured to bind to ASGPR; xxiv) the targeting component can include one or more antibody variable domains or nanobodies that are configured to bind to a mannose 6- phosphate receptor (M6PR) such as cation-independent M6PR (CI-M6PR); xxv) the targeting component can include one or more protein molecules or protein domains, carbohydrates, carbohydrate derivatives or small molecules configured to bind to a M6PR such as CI-M6PR; xxvi) the targeting component can include one or more protein molecules or protein domains, carbohydrates, carbohydrate derivatives or small molecules configured to bind to CD 163; xxvii) the targeting component can include one or more protein molecules or protein domains configured to bind to phosphatidylserine; xxviii) the targeting protein component can include one or more antibody variable domains or nanobodies configured to bind to phosphatidylserine; xxix) the one or more protein molecules or protein domains can be configured to bind the phosphatidylserine via a calcium-dependent mechanism; xxx) the targeting component can include a C2A domain of synaptotagmin 1 ; xxxi) the macromolecule that targets AD AMTS 13- specific antibodies can include at least a first antigen component and a second antigen component, wherein the one molecule of the antigen, antigen fragment or antigen mimetic of the first antigen component is different to the one molecule of the antigen molecule, antigen fragment or antigen mimetic of the second antigen component; xxxii) the macromolecule that targets ADAMTS13-specific antibodies can include at least a first antigen component and additional antigen components, wherein the one molecule of the antigen, antigen fragment or antigen mimetic of the first antigen component is different to additional antigen molecules, antigen fragments or antigen mimetics of the additional antigen components; xxxiii) the method may include administering the macromolecule that targets ADAMTS I 3-specific antibodies in amounts and at dosing frequencies sufficient to remove at least 50% of the target antigen-specific antibody from the circulation or in a tissue or organ in the patient; xxxiv) the method may include administering the macromolecule that targets ADAMTS 13 -specific antibodies in amounts and at dosing frequencies sufficient to remove at least 80% of the target antigen-specific antibody from the circulation or in a tissue or organ in the patient; xxxv) the method may include administering the macromolecule that targets ADAMTS 13 -specific antibodies in amounts and at dosing frequencies sufficient to remove at least 90% of the target antigen-specific antibody from the circulation or in a tissue or organ in the patient; xxxvi) the macromolecule that targets ADAMTS 13-specific antibodies may remove less than 20% of nontarget antibodies in the circulation or in a tissue or organ; xxxvii) the macromolecule that targets ADAMTS 13-specific antibodies may remove less than 10% of non-target antibodies in the circulation or in a tissue or organ; xxxviii) the macromolecule that targets ADAMTS 13- specific antibodies may remove less than 5% of non-target antibodies in the circulation or in a tissue or organ; xxxix) the macromolecule that targets ADAMTS13-specific antibodies may cause degradation of the target antigen-specific antibody by a cell expressing the internalizing cell surface receptor or internalizing cell surface molecule; xl) the macromolecule that targets AD AMTS 13-specific antibodies may be administered to a patient with an autoimmune disease and the target antigen-specific antibody may specifically bind to an autoantigen; xli) the macromolecule that targets ADAMTS 13 -specific antibodies may comprise at least one protein having at least one amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11. SEQ ID NO: 12. SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15. SEQ ID NO: 16. SEQ ID NO: 17. SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37. SEQ ID NO: 38. SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 53, SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 57, SEQ ID NO: 58, SEQ ID NO: 59. SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 62, SEQ ID NO: 63, SEQ ID NO: 64. SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 67, SEQ ID NO: 68, SEQ ID NO: 69. SEQ ID NO: 70, SEQ ID NO: 71 , SEQ ID NO: 72, SEQ ID NO: 73, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 77, SEQ ID NO: 78, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 82, or SEQ ID NO: 83, or a homolog thereof; xlii) the macromolecule that targets ADAMTS 13 -specific antibodies may comprise a heterodimer of proteins having ammo acid sequences of SEQ ID NO: 2 plus SEQ ID NO: 4, SEQ ID NO: 2 plus SEQ ID NO: 5, SEQ ID NO: 2 plus SEQ ID NO: 6, SEQ ID NO: 2 plus SEQ ID NO: 7, SEQ ID NO: 1 plus SEQ ID NO: 8, SEQ ID NO: 9 plus SEQ ID NO: 10, SEQ ID NO: 11 plus SEQ ID NO: 12, SEQ ID NO: 13 plus SEQ ID NO: 14, SEQ ID NO: 3 plus SEQ ID NO: 15, SEQ ID NO: 3 plus SEQ ID NO: 16, SEQ ID NO: 3 plus SEQ ID NO: 17. SEQ ID NO: 2 plus SEQ ID NO: 18, SEQ ID NO: 19 plus SEQ ID NO: 21 plus SEQ ID NO: 22, SEQ ID NO: 19 plus SEQ ID NO: 21 plus SEQ ID NO: 23, SEQ ID NO: 20 plus SEQ ID NO: 21 plus SEQ ID NO: 22, SEQ ID NO: 20 plus SEQ ID NO: 21 plus SEQ ID NO: 23, SEQ ID NO: 2 plus SEQ ID NO: 24, SEQ ID NO: 18 plus SEQ ID NO: 25, SEQ ID NO: 4 plus SEQ ID NO: 25, SEQ ID NO: 6 plus SEQ ID NO: 25, SEQ ID NO: 38 plus SEQ ID NO: 25, SEQ ID NO: 8 plus SEQ ID NO: 25, SEQ ID NO: 33 plus SEQ ID NO: 25, SEQ ID NO: 34 plus SEQ ID NO: 25, SEQ ID NO: 37 plus SEQ ID NO: 25, SEQ ID NO: 26 plus SEQ ID NO: 27, SEQ ID NO: 28 plus SEQ ID NO: 29, SEQ ID NO: 2 plus SEQ ID NO: 30, SEQ ID NO: 31 plus SEQ ID NO: 32, SEQ ID NO: 1 plus SEQ ID NO: 33, SEQ ID NO: 1 plus SEQ ID NO: 34, SEQ ID NO: 8 plus SEQ ID NO: 35, SEQ ID NO: 33 plus SEQ ID NO: 35, SEQ ID NO: 34 plus SEQ ID NO: 35, SEQ ID NO: 37 plus SEQ ID NO: 35, SEQ ID NO: 4 plus SEQ ID NO: 35, SEQ ID NO: 6 plus SEQ ID NO: 35, SEQ ID NO: 18 plus SEQ ID NO: 35, SEQ ID NO: 38 plus SEQ ID NO: 35, SEQ ID NO: 1 plus SEQ ID NO: 36, SEQ ID NO: 1 plus SEQ ID NO: 37, SEQ ID NO: 2 plus SEQ ID NO: 38. SEQ ID NO: 20 plus SEQ ID NO: 47, SEQ ID NO: 20 plus SEQ ID NO: 48, SEQ ID NO: 20 plus SEQ ID NO: 49, SEQ ID NO: 20 plus SEQ ID NO: 50, SEQ ID NO: 20 plus SEQ ID NO: 51, SEQ ID NO: 20 plus SEQ ID NO: 52, SEQ ID NO: 47 plus SEQ ID NO: 53, SEQ ID NO: 48 plus SEQ ID NO: 53, SEQ ID NO: 49 plus SEQ ID NO: 53, SEQ ID NO: 50 plus SEQ ID NO: 53, any of the heterodimers described in Table 1, or homologs thereof.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The following detailed description of various embodiments of the invention will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, illustrative examples are shown in the drawings. It should be understood, however, that the invention is not limited to the precise arrangement and instrumentalities of the embodiments shown in the drawings.

[0038] FIGURE 1 is a schematic diagram of selected cellular events that lead to the degradation of ADAMTS 13 -specific antibodies in the presence of a macromolecule that targets ADAMTS13-specific antibodies.

[0039] FIGURE 2A is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to aN- terminal location of an Fc fragment. The antigen component of the macromolecule that targets ADAMTS 13 -specific antibodies may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0040] FIGURE 2B is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a C- terminal location of an Fc fragment. The antigen component of the macromolecule that targets ADAMTS 13-specific antibodies may include one or more domains of AD AMTS 13, or one or more fragments of ADAMTS13 or an AD AMTS 13 mimetic.

[0041] FIGURE 2C is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a non-terminal location of an Fc fragment. The antigen component of the macromolecule that targets ADAMTS13-specific antibodies may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0042] FIGURE 2D is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including two different antigens fused to the N- terminal locations of an Fc fragment. The antigen components of the macromolecule that targets ADAMTS 13 -specific antibodies may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0043] FIGURE 2E is a schematic diagram of a macromolecule that targets ADAMTS13- specific antibodies including two different antigens fused to the C- terminal locations of an Fc fragment. The antigen components of the macromolecule that targets ADAMTS 13 -specific antibodies may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0044] FIGURE 2F is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including two different antigens fused to the N- and C- terminal locations of the same Fc fragment. The two antigen components of the macromolecule that targets ADAMTS 13-specific antibodies are different and may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0045] FIGURE 2G is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including two different antigens fused to the N- and C- terminal locations of different Fc fragments in an Fc heterodimer. Other embodiments can include three or four different antigen components fused to the N- and C-terminal locations. The two or more antigen components of the macromolecule that targets ADAMTS 13-specific antibodies are different and may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0046] FIGURE 2H is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a terminal location of a protein or protein fragment that binds to a cell surface receptor or cell surface molecule. The protein or protein fragment can be albumin, an antibody single VHH domain, an antibody scFv fragment or an antibody Fab fragment. Alternatively, the protein or protein fragment can be replaced by, or conjugated to, a carbohydrate, carbohydrate derivative or small molecule that binds to a cell surface receptor or cell surface molecule. The antigen component of the macromolecule that targets ADAMTS 13 -specific antibodies may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0047] FIGURE 21 is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including two different antigens fused to terminal locations of a protein or protein fragment that binds to a cell surface receptor or cell surface molecule. The protein or protein fragment can be albumin, an antibody single VHH domain, an antibody scFv fragment or an antibody Fab fragment. Alternatively, the protein or protein fragment can be replaced by, or conjugated to, a carbohydrate, carbohydrate derivative or small molecule that binds to a cell surface receptor or cell surface molecule. The two antigen components of the macromolecule that targets ADAMTS 13-specific antibodies are different and may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0048] FIGURE 2J is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a non-terminal location of a protein or protein fragment that binds to a cell surface receptor or cell surface molecule. The protein or protein fragment can be albumin, an antibody single VHH domain, an antibody scFv fragment or an antibody Fab fragment. Alternatively, the protein or protein fragment can be replaced by, or conjugated to, a carbohydrate, carbohydrate derivative or small molecule that binds to a cell surface receptor or cell surface molecule. The antigen component of the macromolecule that targets ADAMTS 13 -specific antibodies may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0049] FIGURE 2K is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a C- terminal location of an antibody that binds to a cell surface protein or cell surface receptor. The antigen component of the macromolecule that targets ADAMTS 13-specific antibodies may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0050] FIGURE 2L is a schematic diagram of a macromolecule that targets ADAMTS13- specific antibodies including an antigen fused to a C- terminal location of an antibody that binds to a cell surface protein or cell surface receptor. The targeting component is monovalent and comprises one Fab fragment per antibody molecule. The antigen component of the macromolecule that targets AD AMTS 13-specific antibodies may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0051] FIGURE 2M is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a N- terminal location of an Fc fragment and scFv fragments that bind to a cell surface protein or cell surface receptor to the C -termini of the Fc fragment. The antigen component of the macromolecule that targets ADAMTS 13- specific antibodies may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0052] FIGURE 2N is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a C-terminal location of an Fc fragment and scFv fragments that bind to a cell surface protein or cell surface receptor to the N-termini of the Fc fragment. The antigen component of the macromolecule that targets ADAMTS 13- specific antibodies may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0053] FIGURE 20 is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including two different antigens fused to C- terminal locations of an antibody that binds to a cell surface protein or cell surface receptor. The two antigen components of the macromolecule that target AD AMTS 13-specific antibodies are different and may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0054] FIGURE 2P is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including two different antigens fused to C-terminal locations of an antibody that binds to a cell surface protein or cell surface receptor. The targeting component is monovalent and comprises one Fab fragment per antibody molecule. The two antigen components of the macromolecule that target ADAMTS 13-specific antibodies are different and may include one or more domains of ADAMTS 13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic.

[0055] FIGURE 2Q is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including two different antigens fused to the N- terminal locations of an Fc fragment and scFv fragments that bind to a cell surface protein or cell surface receptor to the C-termini of the Fc fragment. The two antigen components of the macromolecule that targets ADAMTS 13-specific antibodies are different and may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0056] FIGURE 2R is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including two different antigens fused to a C-terminal location of an Fc fragment and scFv fragments that bind to a cell surface protein or cell surface receptor to the N-termini of the Fc fragment. The two antigen components of the macromolecule that targets ADAMTS 13-specific antibodies are different and may include one or more domains of ADAMTS 13, or one or more fragments of AD AMTS 13 or an ADAMTS13 mimetic.

[0057] FIGURE 2S is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a N- terminal location of an Fc fragment and protein or protein fragments that bind to a cell surface protein or cell surface receptor to the C- termini of the Fc fragment. The antigen component of the macromolecule that targets ADAMTS13-specific antibodies may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0058] FIGURE 2T is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies including an antigen fused to a C- terminal location of an Fc fragment and protein or protein fragments that bind to a cell surface protein or cell surface receptor to the N- termini of the Fc fragment. The antigen component of the macromolecule that targets ADAMTS13-specific antibodies may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0059] FIGURE 2U is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies comprising two antigen molecules fused to the N-terminal locations of an Fc fragment. The antigen component of the macromolecule that targets ADAMTS13-specific antibodies may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS13 or an ADAMTS13 mimetic.

[0060] FIGURE 2V is a schematic diagram of a macromolecule that targets ADAMTS 13- specific antibodies comprising two antigen molecules fused to the N-terminal locations of an Fc fragment and protein or protein fragments that bind to a cell surface protein or cell surface receptor to the C-termini of the Fc fragment. The antigen components of the macromolecule that targets ADAMTS 13 -specific antibodies may include one or more domains of ADAMTS13, or one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic. FIGURE 3 is a schematic representation of the different domains of AD AMTS 13 (SEQ ID NO: 54. SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 57, SEQ ID NO: 58 and SEQ ID NO: 59), and shows the domains of AD AMTS 13 that are incorporated into exemplary macromolecules that target ADAMTS 13 -specific antibodies.

[0061] FIGURE 4A, 4B, 4C, 4D and 4E show SDS-PAGE analyses of exemplary FcRn- targeting macromolecules that target ADAMTS 13-specific antibodies run under reducing and non-reducing conditions.

[0062] FIGURE 4F shows size exclusion analyses of exemplary FcRn-targeting macromolecules that target ADAMTS 13 -specific antibodies.

[0063] FIGURE 5A shows the binding of an exemplary FcRn-targeting macromolecule that targets ADAMTS 13 -specific antibodies to two recombinant (human IgGl / kappa) ADAMTS 13-specific antibodies.

[0064] FIGURE 5B shows the binding of an exemplary FcRn-targeting macromolecule that targets ADAMTS 13 -specific antibodies to FcRn at pH 6.0.

[0065] FIGURE 6 shows interaction analyses of exemplary FcRn-targeting macromolecules that target ADAMTS 13-specific antibodies with the A2 domain of von Willebrand factor (VWF).

[0066] FIGURES 7A, 7B and 7C show HPLC analyses of exemplary FcRn-targeting macromolecules that target ADAMTS 13-specific antibodies following incubation at 37°C for 5 or 14 days to evaluate their stability.

[0067] FIGURE 8 shows size exclusion analyses of exemplary FcyRIIb-targeting macromolecules that target ADAMTS 13-specific antibodies.

[0068] FIGURES 9A, 9B and 9C shows graphs reporting exemplary data to demonstrate the effects of mutations that reduce binding to FcyRs on the interaction between exemplary' FcRn- targeting macromolecules that target ADAMTS 13 -specific antibodies with FcyRs.

[0069] FIGURE 9D shows graphs reporting exemplary data to demonstrate the effects of mutations that increase binding to the inhibitory7receptor, FcyRIIb, on the interaction between exemplary FcyRIIb-targeting macromolecules that target ADAMTS 13-specific antibodies with FcyRIIb. FIGURE 9E and 9F show graphs reporting exemplary data to demonstrate the effects of mutations that reduce binding to complement Clq on the interaction between exemplary FcRn-targeting macromolecules that target ADAMTS13-specific antibodies with Clq.

[0070] FIGURES 10 A, 10B and 10C show graphs reporting exemplars’ data of the binding of ADAMTS 13-specific antibodies in plasma samples of patients to different exemplary FcRn- targeting macromolecules that target ADAMTS 13 -specific antibodies.

[0071] FIGURES HA, 11B, 11C, HD, HE, HF, 11G, 11H, 111, 11 J, 11K and HL show graphs reporting exemplary’ data to demonstrate the efficiency with which exemplary’ FcRn- targeting macromolecules that target ADAMTS 13 -specific antibodies specifically deplete ADAMTS 13-specific antibodies from patient plasma samples.

[0072] FIGURE 12 shows a graph reporting exemplary data to demonstrate that injection of an exemplary FcRn-targeting macromolecule that targets ADAMTS 13-specific antibodies into mice leads to the specific depletion of ADAMTS 13-specific antibodies from the serum.

[0073] FIGURE 13 shows a graph reporting exemplary data of the binding of exemplary FcyRIIb-targeting macromolecules that target ADAMTS 13-specific antibodies to ADAMTS 13-specific antibodies in plasma samples of patients.

[0074] FIGURE 14 shows a graph reporting exemplary data to demonstrate the ability of exemplary FcyRIIb-targeting macromolecules that target ADAMTS 13 -specific antibodies to deliver ADAMTS 13-specific antibodies to FcyRIIb-expressing cells.

[0075] FIGURE 15A shows a graph reporting exemplary data of the binding of exemplary ASGPR-targeting macromolecules that target ADAMTS 13 -specific antibodies to recombinant ASGPR.

[0076] FIGURES 15B shows the binding of an exemplary ASGPR-targeting macromolecule that targets ADAMTS 13-specific antibodies to an ADAMTS 13-specific antibody.

[0077] FIGURE 16 shows a graph reporting exemplary data to demonstrate the ability of exemplary ASGPR-targeting macromolecules that target ADAMTS 13 -specific antibodies to deliver ADAMTS 13-specific antibodies to ASGPR-expressing cells.

[0078] FIGURE 17 shows exemplary monovalent, divalent and trival ent targeting components that bind to ASGPR.

[0079] FIGURE 18 shows exemplary targeting components that bind to ASGPR. DETAILED DESCRIPTION

[0080] Various publications, articles and patents are cited or described in the background, summary and throughout the specification; each of these references is herein incorporated by reference in its entirety. Discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is for the purpose of providing context for the disclosure provided herein. Such discussion is not an admission that any of these matters, singularly or in combination, form part of the prior art with respect to any disclosure provided herein.

[0081] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the disclosure provided herein pertains. Otherwise, certain terms used herein have the meanings as set forth in the specification.

[0082] This disclosure relates to engineered proteins or molecules, and more specifically, to macromolecules that target ADAMTS13-specific antibodies, wherein such macromolecules are fusion proteins or molecules that are configured to selectively target ADAMTS 13 -specific antibodies for depletion from the body. Macromolecules that target ADAMTS 13 -specific antibodies cause the selective degradation of the targeted ADAMTS 13-specific antibodies by binding to the antigen-specific antibodies and directing them to late endosomes or lysosomes, which contain degradative enzymes. Macromolecules that target ADAMTS 13 -specific antibodies are fusion proteins or molecules that comprise at least a targeting component and an antigen component. The targeting component comprises a protein or protein fragment or other molecule such as a carbohydrate, carbohydrate derivative or small molecule that is configured to bind to an internalizing cell surface receptor or other internalizing cell surface molecule. The antigen component comprises one or more domains of ADAMTS13, one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic that is / are recognized by the targeted antigen-specific antibody.

[0083] Upon binding of the antigen-specific antibody to the antigen component, a complex is formed comprising the macromolecule that targets ADAMTS 13-specific antibodies and the ADAMTS 13-specific antibody. The complex is also configured to bind to the cell surface receptor or other cell surface molecule, allowing cellular internalization of a complex that includes the macromolecule that targets ADAMTS 13 -specific antibodies, the ADAMTS13- specific antibody, and the targeted cell surface receptor or other cell surface molecule (see FIGURE 1). The targeted cell surface receptor or cell surface molecule may dissociate from the complex upon entry into the endosomes, due to acidic pH, low calcium concentrations and / or other conditions that distinguish the endosomal environment from the extracellular environment. Internalization into endosomes and lysosomal entry results in the selective degradation of the complex.

[0084] The term "‘antigen component’7as used herein refers to an antigen, antigen fragment or antigen mimetic configured to specifically bind antibodies that recognize ADAMTS13 or domains thereof.

[0085] The term “ADAMTS 13 -specific antibody” as used herein refers to an antibody or a naturally occurring fragment of an antibody such as a half-molecule that binds to ADAMTS 13, ADAMTS 13 fragment or ADAMTS 13 mimetic.

[0086] The term “ADAMTS 13 fragment” as used herein refers to a part of ADAMTS 13 that can be recognized by ADAMTS 13 -specific antibodies.

[0087] The term “ADAMTS 13 mimetic” as used herein refers to a protein, protein fragment, peptide or other molecule that has the same overall shape and properties as the part of the ADAMTS 13 that is recognized by ADAMTS 13-specific antibodies.

[0088] The term “cell surface receptor” or “cell surface molecule” as used herein refers to a protein or other biological molecule (e.g. phospholipid, carbohydrate) that is exposed on the plasma membrane of a cell and also internalizes into the cell.

[0089] A macromolecule that targets ADAMTS 13-specific antibodies may comprise an antigen component comprising one or more domains of ADAMTS 13, one or more fragments of ADAMTS13 or an ADAMTS13 mimetic fused to a targeting component comprising an Fc fragment of an IgG antibody (herein also referred to as “immunoglobulin Fc fragment”), an Fc fragment with increased binding affinity for FcRn, an FcRn-specific nanobody, an FcRn- specific antibody that binds to FcRn through its variable region, an Fc fragment that binds with increased affinity to the inhibitory FcyRIIb, albumin or an albumin fragment, a PS-binding protein, a TfR-specific antibody, an ASGPR-binding protein or ligand, or other protein, protein fragment or other molecule such as a carbohydrate, carbohydrate derivative or small molecule that is configured to bind to a cell surface receptor or other cell surface molecule identifiable by skilled persons in the art upon reading of the present disclosure.

[0090] Examples of macromolecules that target ADAMTS 13-specific antibodies described herein include targeting components that are configured to bind to cell surface molecules such as human FcRn, exposed phosphatidylserine (PS), the transferrin receptor (TfR), the asialoglycoprotein receptor (ASGPR), the inhibitory Fc gamma receptor, FcyRIIb, and the scavenger receptor, CD 163 with affinities (dissociation constants) of less than 10 pM at near neutral pH.

[0091] FcRn, TfR. ASGPR. FcyRIIb and CD163 are proteins, PS is a phospholipid that may be found on the surface and within different cell types within the body. This invention is not limited to targeting these receptors or cell surface molecules, and many other targets could be envisaged such as the low density lipoprotein receptor, high density lipoprotein receptor, T cell receptor. B cell receptor. G-protein coupled receptors, insulin receptor, glucagon receptors, galactose receptors, VEGF receptors, mannose receptors, mannose 6-phosphate receptors (e.g. cation-independent mannose 6-phosphate receptor, CI-M6PR), CD38, insulin-like growth factor receptor among others identifiable by those skilled in the art. Other targets can be identified in, for example, the following publications or databases: Cell surface receptor protein atlas (Bausch-Fluck. D.. Hofmann, A., Bock. T., Frei, A.P., Cerciello. F., Jacobs. A.. Moest. H., Omasits, U., Gundry, R.L., Yoon, C., Schiess, R., Schmidt, A., Mirkowska, P., Hartlova, A., Van Eyk, J.E., Bourquin, J-P., Aebersold, R., Boheler, K.R., Zandstra, P., Wollscheid, B. (2015) A mass spectrometric-derived cell surface protein atlas. PLoS One 10: e0121314), and the Human protein atlas (https: / / www.proteinatlas.org / humanproteome / secretome).

[0092] The targeting component can bind the cell surface receptor or other cell surface molecule with an affinity (dissociation constant) of less than 10 pM at near-neutral pH, which may be greater than 6.8 and less than 7.5.

[0093] Accordingly, the targeting component of a macromolecule that targets ADAMTS13- specific antibodies can include any type of molecule that is configured to specifically bind to a cell surface receptor or other cell surface molecule. Such molecules can include proteins, protein fragments, polynucleotides such as ribonucleic acids or deoxyribonucleic acids, polypeptides, polysaccharides, lipids, ammo acids, peptides, carbohydrates, carbohydrate derivatives and / or other small or large molecules and / or polymers identifiable by skilled persons in the art upon reading of the present disclosure. For example, the targeting component of a macromolecule that targets ADAMTS 13 -specific antibodies can comprise a carbohydrate, carbohydrate derivative or other small molecule that is a ligand for a cellular receptor. Examples of such targeting components for ASGPR are described in the following: International Publication No. WO 2022 / 157626 Al, Degradation of extracellular targets, inventors: Allan, M., Bagdanoff, J., Barnes, D.W., Blankenship, J., Bradner, J., Clairmont, K., Granda, B., Junge, G., Smith, T., Traggiai, E., Wamcke, M.: International Publication No. WO 2022 / 192478 Al, Bifunctional degraders of galactose-deficient immunoglobulins, inventors: Dubowchik, G.M., Spiegel, D., Caldwell, R.M.; US Patent No. 12,128,105 B2, Molecular degraders of extracellular proteins, inventors: Caianiello, D., Deramon, E., Spiegel, D.; International Publication No. WO 2025 / 035052 Al, Molecular degraders for the treatment of IgA nephropathy, inventors: Kazmierski, W., Pracitto, R., Dubowchik, G.M., Marcin, L.R., Bunin, A., Rossi. A.M., Iben, L.G., McGrath. K.., Lee, S.. Todd, M.; International Publication No. WO 2025 / 081 173 A2, Bispecific molecular degraders of pathogenic proteins, inventors: Bunin, A., Car, B., Dow, M., Gardin, T., Lipson, S., Marcin, L.R., Mellott, D., Murray, S., Pirman, D., Velaparthi, U.; International Publication No. WO 2025 / 035040 Al, Lysosomal targeting bifunctional molecules for degradation of muscle-specific kinase autoantibodies, inventors: Chen, T., Iwig, J., Lewis, J.G., Lieser, R., Staben, S., Totten, S.M., Turtle, E.D.,. Examples of such targeting components for mannose-6-phosphate receptor and insulin-like growth factor 2 receptor are described in the following: International Publication No. WO 2022 / 157626 Al, Degradation of extracellular targets, inventors: Allan, M., Bagdanoff, J., Bames. D.W.. Blankenship. J., Bradner, J.. Clairmont. K.. Granda, B., Junge. G.. Smith. T.. Traggiai, E., Wamcke, M..

[0094] The macromolecule that targets ADAMTS13-specific antibodies can comprise at least a first targeting component and a second targeting component, wherein the protein or protein fragment of the first targeting component is configured to bind to a different cell surface receptor or a different cell surface molecule than the protein or protein fragment of the second targeting component.

[0095] The macromolecule that targets ADAMTS13-specific antibodies can also comprise one or more domains of ADAMTS13, one or more fragments of ADAMTS13 or an ADAMTS13 mimetic that are attached at different positions such as the N- and C-termini of the targeting component.

[0096] As shown in FIGURE 1, a macromolecule that targets ADAMTS13-specific antibodies binds selectively to ADAMTS 13 -specific antibodies, but not antibodies that bind to other antigens, in the extracellular space. The macromolecule: ADAMTS 13-specific antibody complex (with one or two macromolecules bound to each antibody) is then internalized into cells due to binding of the macromolecule to an internalizing receptor such as FcRn. These ADAMTS 13-specific antibody:macromolecule complexes enter lysosomes where the complexes are degraded. Through this mechanism of selective depletion, a macromolecule that targets ADAMTS 13 -specific antibodies targets and selectively depletes ADAMTS13-specific antibodies from the body without adversely affecting the levels of antibodies of non-targeted specificities.

[0097] A macromolecule that targets ADAMTS 13 -specific antibodies as described herein can target and selectively deplete ADAMTS 13-specific antibodies from the body without having an adverse clinical effect in the patient due to depleting antibodies of non-targeted specificities. Such adverse clinical effects that are to be avoided include, for example, immunosuppression, and symptoms thereof, such as pinkeye, bronchitis, ear infections, sinus infections, cold, diarrhea, pneumonia, yeast infection, meningitis, skin infections, and other opportunistic infections, particularly opportunistic infections normally controlled through antibody -mediated immune responses; and blood disorders, such as low platelet counts or anemia, and hypogammaglobulinemia and symptoms thereof, such as abdominal pain, bloating, nausea, vomiting, diarrhea, or weight loss.

[0098] In general, a macromolecule that targets ADAMTS 13 -specific antibodies according to this disclosure is configured to specifically bind a cell surface receptor / molecule at nearneutral pH, which may be greater than 6.8 and less than 7.5, via a targeting component and also specifically bind to ADAMTS 13 -specific antibodies via one or more antigen components that are fused directly or indirectly to the targeting component. The term “specifically bind" as used herein refers to a detectable selective intermolecular interaction between the targeting component and the cell surface receptor / molecule, or between the antigen component and the ADAMTS 13-specific antibody. For example, to specifically bind, the antigen needs to show a detectable interaction with the ADAMTS 13 -antibodies that are being targeted, whilst not showing a detectable interaction with other antibodies that are specific for different antigens. Techniques for detecting specific binding are known within the art, such as ELISA, surface plasmon resonance and other methods identifiable by skilled persons in the art.

[0099] Accordingly, a macromolecule that targets ADAMTS 13 -specific antibodies allows at least a portion of the ADAMTS 13-specific antibody in the body of a patient to be internalized into cells that express the targeted cell surface receptor, or targeted other cell surface molecule, and thereafter intracellularly degraded.

[0100] A macromolecule that targets ADAMTS 13-specific antibodies according to this disclosure may avoid the elicitation of immune responses by the insertion of mutations to reduce or eliminate (activatory) FcyR binding and / or complement binding, which is expected to decrease the formation of potentially inflammatory immune complexes. A macromolecule that targets ADAMTS13-specific antibodies may contain one molecule of antigen (i.e. one or more domains of ADAMTS 13, one or more fragments of ADAMTS13 or an ADAMTS13 mimetic), whereas other macromolecules that target ADAMTS13-specific antibodies according to the present disclosure can contain more than one molecule of an antigen, antigen fragment, or antigen mimetic. The bivalent nature of the antibodies that are bound by macromolecules that target ADAMTS13-specific antibodies may result in complexes of two macromolecules that target AD AMTS 13 -specific antibodies per antibody, which through target receptor dimerization is expected to increase the efficiency of lysosomal delivery of the macromolecule-antibody complexes.

[0101] A macromolecule that targets ADAMTS13-specific antibodies according to the present disclosure can contain more than one molecule of an antigen, antigen fragment, or antigen mimetic. A macromolecule that targets ADAMTS13-specific antibodies can comprise at least a first antigen component and a second antigen component, wherein the first antigen component (one or more domains of ADAMTS13, one or more fragments of ADAMTS 13 or an ADAMTS13 mimetic) is different to the second antigen component. Accordingly, a macromolecule that targets ADAMTS13-specific antibodies comprising at least a first antigen component and a second antigen component allows clearance of ADAMTS 13 -specific antibodies of more than one epitope specificity. Similarly, a macromolecule that targets ADAMTS 13-specific antibodies can also comprise more than two antigen components that are either the same or different.

[0102] In addition, a macromolecule that targets ADAMTS 13-specific antibodies may contain human or humanized proteins or protein fragments to avoid or decrease the possibility of an immune reaction to the macromolecule that targets ADAMTS 13-specific antibodies when administered to a human. In some embodiments, the one or more domains of ADAMTS 13, one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic, is a human or humanized protein or protein fragment for administration of the macromolecule that targets ADAMTS 13- specific antibodies to a human. In some embodiments, the targeting component is also a human or humanized protein or protein fragment, such as a human antibody fragment or human albumin or albumin fragment, or a humanized antibody or humanized antibody fragment for administration of the macromolecule that targets ADAMTS 13 -specific antibodies to a human. If a macromolecule that targets ADAMTS 13 -specific antibodies is developed for use in a non- human animal, then proteins or protein fragments derived from or engineered to be immunologically compatible with that animal may be used instead.

[0103] FIGURES 2A, 2B and 2C are schematics of macromolecules that target AD AMTS 13- specific antibodies including antigen components fused to a targeting component comprising the Fc fragment of IgG. As understood by persons skilled in the art, the Fc fragment of an IgG is all of the lower base of the antibody's Y-shape, which is the sulfhydryl-bridged hinge region and the CH2 and CH3 domains. Macromolecules that target AD AMTS 13 -specific antibodies can comprise an Fc fragment that does not have the hinge region, or the hinge region does not have sulfhydryl bridges or the hinge region has deletions. The Fc fragment allows a macromolecule that targets ADAMTS13-specific antibodies to bind an FcRn molecule on an FcRn-expressing cell. In the example shown in FIGURE 2A, 2B. 2D, 2E, 2F or 2G. one or more antigen components may be fused to Fc fragment at the N- or C-terminus of the hinge- CH2-CH3. When one or more antigen components are fused to the Fc fragment and the resulting antigen-Fc fragment dimerizes with another Fc fragment lacking an antigen or attached to different antigen components, using the knobs-into-holes strategy (for example, as described in Atwell. S., Ridgway. J.B.B.. Wells. J.A., Carter, P. (1997) Stable heterodimers from remodeling the domain interface of a homodimer using a phage display library. J. Mol. Biol., 270, 26-35; Moore, G.L., Bautista, C., Pong, E., Nguyen, D.H., Jacinto, J., Eivazi, A., Muchhal, U.S., Karki, S., Chu, S.Y., Lazar, G.A. (2011) A novel bispecific antibody format enables simultaneous bivalent and monovalent co-engagement of distinct target antigens. MAbs 3, 546-557), a heterodimeric macromolecule that targets ADAMTS I 3-specific antibodies as shown is produced. A macromolecule that targets ADAMTS13-specific antibodies has an Fc fragment with a monomeric display of the antigen component, or of each antigen component if more than one antigen component is present. In addition to, or instead of, knobs-into-holes mutations, a macromolecule that targets ADAMTS13-specific antibodies can comprise electrostatic steering mutations (for example, as described in Gunasekaran, K., Pentony, M., Shen, M., Garrett, L., Forte, C., Woodward, A., Ng, S.B., Bom, T., Retter, M., Manchulenko, K_, Sweet, H., Foltz, I.N., Wittekind, M., Yan, W. (2010) Enhancing antibody Fc heterodimer formation through electrostatic steering effects: applications to bispecific molecules and monovalent IgG. J Biol Chem 285, 19637-19646) to promote heterodimer formation. Other approaches can also be used to generate heterodimers, such as the insertion of a (G*iS)i2 (SEQ ID NO: 84) linker peptide between the C-terminus of the antigen-Fc fusion and N-terminus of a second Fc fragment (for example, as described in Zhou. L., Wang, H-Y., Tong, S., Okamoto, C.T., Shen, W-C., Zaro. J.L. (2016) Single chain Fc-dimer-human growth hormone fusion protein for improved drug delivery. Biomaterials, 117, 24-31). Protein sequences of examples of macromolecules that target ADAMTS 13 -specific antibodies comprising knobs-into-holes mutations and mutations that reduce Fc gamma receptor and complement binding are presented in the Sequence Listing.

[0104] Examples of knobs-into-holes mutations include T366W:T366S / L368A / Y407V (for example as described in Atwell, S., Ridgway, J.B.B., Wells, J A., Carter, P (1997) Stable heterodimers from remodeling the domain interface of a homodimer using a phage display library. J. Mol. Biol., 270, 26-35) or Y349T / T394F: S364H / F405A and Y349T / F405F: S364H / T394F (for example as described in Moore, G.L., Bautista, C., Pong, E., Nguyen, D.H., Jacinto, J., Eivazi, A., Muchhal, U.S., Karki, S., Chu, S.Y., Lazar, G.A. (2011) A novel bispecific antibody format enables simultaneous bivalent and monovalent co-engagement of distinct target antigens. MAbs 3. 546-557) among others identifiable by persons skilled in the art. The residue numbering of these exemplary knobs-into-holes mutations refers to the EU antibody numbering system, as would be understood by persons skilled in the art.

[0105] Examples of electrostatic steering mutations include E356K / D399K:K392D / K409D and K409D / K370D:D357K / D399K (for example as described in Gunasekaran, K., Pentony, M.. Shen, M., Garrett, L.. Forte, C., Woodward, A., Ng, S.B., Bom, T.. Retter, M., Manchulenko, K., Sweet, H., Foltz, I.N., Wittekind. M., Yan. W. (2010). Enhancing antibody Fc heterodimer formation through electrostatic steering effects: applications to bispecific molecules and monovalent IgG. J Biol Chem 285, 19637-19646) among others identifiable by persons skilled in the art. The residue numbering of these exemplary' electrostatic steering mutations refers to the EU antibody’ numbering system, as would be understood by persons skilled in the art.

[0106] The Fc fragment may be modified to eliminate or substantially reduce the binding affinity7for Fc gamma receptors, in particular for aclivalory FcyRs, and complement (Clq). This modification prevents inflammatory responses caused by the formation of multimeric immune complexes. For example, the following mutations can be inserted in the Fc fragment: L234S / L235T / G236R, L234A / L235A / D265S or G236R / L328R (for example as described in Wilkinson, L, Anderson, S., Fry, J., Julien, L.A., Neville, D., Qureshi, O., Watts, G., Hale, G. (2021) Fc-engineered antibodies with immune effector functions completely abolished. PLoS ONE, 16, e0260954; Kotanides, H., Li, Y., Malabunga, M., Carpenito, C., Eastman, S.W., Shen. Y., Wang, G., Inigo, I., Surguladze. D., Pennello, A.L., Persaud, K., Hindi, S., Topper, M.. Chen, X., Zhang, Y., Bulaon, D.K., Bailey, T., Lao, Y., Han, B.. Torgerson. S., Chin, D., Sonyi, A., Haider, J.N., Novosaidly, R.D., Moxham, C.M., Plowman, G.D., Ludwig, D.L., Kalos, M. (2020) Bispecific targeting of PD-1 and PD-L1 enhances T-cell activation and antitumor immunity. Cancer Immunol. Res., 8, 1300-1310; Horton, H.M., Bemett, M.J., Pong, E., Peipp, M., Karki, S., Chu, S.Y.. Richards, J.O., Vostiar, L, Joyce, P.F., Repp, R.. Desjarlais, J.R., Zhukosky, E. (2010) Potent in vitro and in vivo activity of an Fc-engineered anti-CD19 monoclonal antibody against lymphoma and leukemia. Cancer Res., 68, 8049-8057; Moore, G.L., Bautista, C., Pong, E., Nguyen, D.H., Jacinto, J., Eivazi, A., Muchhal, U.S., Karki, S., Chu, S.Y., Lazar, G.A. (2011) A novel bispecific antibody format enables simultaneous bivalent and monovalent co-engagement of distinct target antigens. MAbs, 3, 546-557), N297A or N297Q (for example as described in Tao, M-H., Morrison, S.L. (1989) Studies of aglycosylated chimeric mouse-human IgG: role of carbohydrate in the structure and effector functions mediated by the human IgG constant region. J. Immunol., 143, 2595-2601; Lux, A., Yu. X., Scanlan, C.N., Nimmerjahn, F. (2013) Impact of immune complex size and glycosylation on IgG binding to human FcyRs. J. Immunol., 190, 4315-4323), D265A (for example as described in Lux, A., Yu, X., Scanlan, C.N., Nimmerjahn, F. (2013) Impact of immune complex size and glycosylation on IgG binding to human FcyRs. J. Immunol.. 190, 4315-4323; Clynes, R.A.. Towers. T.L.. Presta. L.G., Ravetch, J.V. (2000) Inhibitory Fc receptors modulate in vivo cytotoxicity against tumor targets. Nat. Med. 6, 443-446), L234A / L235A (for example as described in Wines, B.D., Powell, M.S., Parren, P.W.H.I., Bames, N., Hogarth, P.M. (2000) The IgG Fc contains distinct Fc receptor (FcR) binding sites: the leukocyte receptors FcyRI and FcyRIla bind to a region in the Fc distinct from that recognized by neonatal FcR and protein A. J. Immunol., 164, 5313-5318), and L234A / L235A / P329G (for example as described in Schlothauer, T., Herter, S., Koller, C.F., Grau-Richards, S., Steinhart, V., Spick. C., Kubbies. M., Klein, C., Umana, P.. Mossner, E. (2016) Novel human IgGl and IgG4 Fc-engineered antibodies with completely abolished effector functions. Prot. Eng. Des. Sei., 29, 457-466), among others identifiable by persons skilled in the art. The residue numbering of these exemplary’ mutations to reduce binding to Fc gamma receptors and complement (C 1 q) refers to the EU antibody numbering system, as would be understood by persons skilled in the art. Other mutations to ablate FcyR and / or complement binding that target residues at. or in proximity to, the location of the FcyR and complement binding sites can be used. These sites on the Fc region of IgG have been localized (for example, as described in Jefferis, R., Lund, J. (2002) Interaction sites on human IgG-Fc for FcyR: current models. Immunol. Letts., 82, 57- 65; Duncan, A.R., Winter. G. (1988) The binding site for Clq on IgG. Nature, 332, 738-740; Idusogie, E.E., Presta, L.G., Gazzano-Santoro, H., Totpal, K., Wong, P.Y., Ultsch, M., Meng, G., Mulkerrin, M.G. (2000) Mapping of the Clq binding site on rituxan, a chimeric human antibody with a human IgGl Fc. J. Immunol., 164, 4178-4184; Hogarth, P.M., Anania, J., Wines. B.D. (2014) The FcyR of humans and non-human primates and their interaction with IgG: implications for induction of inflammation, resistance to infection and the use of therapeutic monoclonal antibodies. Curr. Top. Microbiol. Immunol., 382, 321-352).

[0107] A macromolecule that targets ADAMTS13-specific antibodies may comprise Fc fragments derived from immunoglobulin classes or isotypes that do not bind, or have very weak binding, to Fc gamma receptors or complement such as human IgG2 or human IgG4.

[0108] The Fc fragment of a macromolecule that targets ADAMTS13-specific antibodies may be modified to substantially increase its binding affinity for FcRn at near-neutral pH as compared to unmodified Fc fragments. For example, the dissociation constant between the Fc fragment and FcRn at near-neutral pH (greater than 6.8 and less than 7.5) may be less than 10 pM as determined by surface plasmon resonance or other biophysical method. However, the Fc fragment may have a similar or increased affinity for FcRn as compared to an unmodified Fc fragment at acidic endosomal pH (about 6.0), or it may be modified to have a much lower or negligible binding affinity for FcRn at endosomal pH as compared to an unmodified Fc fragment. The increase in binding affinity at near neutral pH allows each macromolecule that targets ADAMTS13-specific antibodies to cause its bound target antigen-specific antibody to be efficiently internalized and trafficked into late endosomes or lysosomes in FcRn-expressing cells. Enhanced binding affinity of the Fc fragment for FcRn may be achieved by insertion of mutations. Naturally-occurring IgGs have a substantially higher binding affinity for FcRn at acidic pH levels as opposed to near-neutral pH. This property' is essential for the recycling and transport of IgG within FcRn-expressing cells. In contrast, an increase in binding affinity for FcRn at pH 7.4, for example, results in receptor-mediated internalization into cells and lysosomal delivery. Further, for FcRn-targeting macromolecules that target ADAMTS13- specific antibodies and comprise Fc fragments, linkage of the antigen component(s) to the C- terminus / termini (CH3 domain) of the Fc fragment, rather than to the N-terminus / termini, are exemplary embodiments.

[0109] In additional embodiments, the Fc fragment can have mutations to enhance binding to the inhibitory Fc receptor, FcyRIIb. Such mutations include P238D, G237D / P271G / A330R, G237D / H268D / P271G / A330R or G236N / H268D / A330K, S267E / L328F or combinations thereof (for example, as described in Mimoto, F., Katada. H., Kadono, S., Igawa, T., Kuramochi, T., Muraoka, M., Wada, Y., Haraya, K., Miyazaki, T., Hattori, K. (2013) Engineered antibody Fc variant with selectively enhanced FcyRIIb binding over both FcyRIIaR131and FcyRIIa11131. Prot. Eng. Des. Sei., 26, 589-598; Hori, Y., Ohmine, K., Katada, H., Noguchi, Y., Sato, K, Nambu, T., Adeline, L.R., Wan, G.S., Haraya, K, Ozeki, K, Nanami, M., Tachibana, T., Sampei, Z., Kuramochi, T., Nezu, J., Hattori, K., Igawa, T. (2022) Elimination of plasma soluble antigen in cynomolgus monkey s by combining pH-dependent antigen binding and novel Fc engineering. MAbs, 14: 1, 2068213; Chu, S.Y., Vostiar, I., Karki, S., Moore, G.L., Lazar, G.A., Pong, E., Joyce. P.F., Szymkowski. D.E.. Desjarlais, J.R. (2008) Inhibition of B cell receptor-mediated activation of primary human B cells by coengagement of CD19 and FcyRIIb with Fc-engineered antibodies. Mol. Immunol., 45, 3926-3933). The residue numbering of these exemplary mutations to enhance binding to FcyRIIb refers to the EU numbering system, as would be understood by persons skilled in the art. Additional mutations that enhance binding to FcyRIIb are described in: International Publication No. WO 2025 / 030003 A2, Molecules for controlling autoimmune response, inventors: Gutierrez, D.A., Logtenberg, M.E., Capilli, A.D.

[0110] As shown in FIGURES 2A, 2B and 2C, the antigen component may be attached to the Fc fragment at different terminal or non-terminal locations. Any location that does not prevent specific FcRn binding or binding to other target receptors such as FcyRIIb is suitable. For FcRn targeting, such locations include amino acid residues that are sufficiently distant from the FcRn interaction site (encompassing residues 252-256, 309-311, 433-436 at the CH2-CH3 domain interface: EU numbering used for residue numbers). For FcyRIIb targeting, such locations include amino acid residues that are sufficiently distant from the FcyRIIb interaction site so as not to either directly or sterically block FcRn or FcyRIIb binding, as would be identifiable by skilled persons in the art.

[0111] The antigen component may be fused to the Fc fragment in any suitable manner, including attachment via a chemical reaction, attachment through a linker, or during formation of a single combined antigen-Fc fragment protein. Examples of chemical coupling that could be used are: amine-to-amine (NHS esters), sulfhydryl-to-sulphydryl (maleimide), amine-to- sulfhydryl (NHS ester / maleimide), sulfydryl-to-carbohydrate (maleimide / hydrazide), or attachment via an unnatural amino acid with the desired chemical reactivity. This unnatural amino acid can be inserted during recombinant production of the Fc fragment and / or antigen. Polyethyleneglycol (PEG) spacers can also be inserted between the chemically conjugated proteins, protein fragments or other molecules. Possible linkers include repeats of glycineserine (Gly-Ser or GS) linker peptides, or other more rigid linker peptides, that are encoded in the recombinant expression plasmid for the antigen-Fc fusion. Linkage chemistry, sites of linkage and choice of peptide can be guided by molecular modeling, and can be designed to minimize loss of binding activity of the antigen or the protein / protein fragment targeting the cell surface molecule, as would be understood by skilled persons in the art.

[0112] FIGURES 2D, 2E, 2F and 2G are schematic representations of macromolecules that target ADAMTS 13 -specific antibodies and include two different antigen fusions fused to different terminal locations in an Fc heterodimer. Macromolecules that target ADAMTS 13- specific antibodies could also include 3, 4 or more different antigen components attached to the N- and C-termini or non-terminal location(s) of the Fc fragment. The different antigen components may include one or more domains of ADAMTS 13, one or more fragments of ADAMTS 13 or an ADAMTS 13 mimetic and can be linked to the Fc fragments using different linker sequences such as GGGGS (G4S. SEQ ID NO: 85), GS, or other linkers known to those with skill in the art.

[0113] FIGURES 2H, 21 and 2J are schematic representations of macromolecules that target ADAMTS 13-specific antibodies in which one or more antigen components are attached to albumin, an antibody variable region (single domain or nanobody), antibody scFv or Fab fragment. The antibody variable region specifically binds to a cell surface receptor or cell surface molecule such as FcRn, the transferrin receptor (TfR), asialoglycoprotein receptor (ASGPR) or CD163. Antibodies or antibody fragments that bind to FcRn and could comprise macromolecules that target ADAMTS 13-specific antibodies include SyntOOl (International Publication No. WO 2106 / 183352 Al, Humanized affinity -matured anti-FcRn antibodies, inventors: Blumberg, L.J, Blumberg, R.S., Jones, S.D., Roopenian, D., Holgate, R.G.E., Jones, T.D., Hearn, A.R.) and 1519 (International Publication No. WO 2106 / 180765 Al, Anti-FcRn antibodies, inventors: Bhatta, P , Dave, E., Heywood, S.P., Humphreys, D.P., Smith, B.J.). Examples of antibodies or antibody fragments that bind to ASGPR and could comprise macromolecules that target ADAMTS13-specific antibodies include 51A12 or affinity- matured (mutated) variants such as 51A12_A6 that have been described previously (International Publication No. WO 2014 / 023709 / A1; ASGPR antibodies and uses thereof; inventors: Hofer, T., Ji, C., Moessner, E., Umana, P). Examples of antibodies or antibody fragments that bind to CD 163 and could comprise macromolecules that target ADAMTS13- specific antibodies are described in: International Publication No. WO 2022 / 063880 Al, Compound for the prevention or treatment of myasthenia gravis, inventors: Smrzka. O, Wanko. B. The anti bod}' variable region that is used in a macromolecule to target ADAMTS13-specific antibodies may be an entire variable region or a fragment thereof, so long as it can specifically bind to a cell surface receptor or cell surface molecule. The antibody variable region may include portions of a non-variable region of an antibody that is configured to bind to a cell surface receptor or cell surface molecule. For example, the antibody variable region may be a single-domain antibody (sdAb) or camelid-derived VHH domain (also commonly referred to as a nanobody). Such variable regions have the overall fold of an immunoglobulin domain, comprising two anti-parallel p-sheets. and can also include domains from other members of the immunoglobulin superfamily such as T cell receptor variable domains, constant region domains of antibodies or domains of the coreceptor, CD4, among others identifiable by persons skilled in the art. The antibody variable region may be present as a monomer as shown in FIGURES 2H, 21 or 2J, or as a multimer. For example, if the antibody variable region is present as a nanobody, it may be engineered with a linker peptide such as GSSGGSGGGGS (SEQ ID NO: 86) between the C-terminus of the first nanobody and the N-terminus of the second nanobody to form a dimer, resulting in increased binding avidity7for target receptor / molecule. If the antibody variable region is a nanobody or another protein that is engineered to form multimers, variants without the antigen component may be included during generation of a macromolecule that targets AD AMTS 13-specific antibodies so that multimers contain only one copy of antigen. Alternatively, the antibody variable regions can be attached to two or more different antigen components. Antibody variable regions can also include heterodimers of heavy chain variable (VH) domains linked by peptide linkers to light chain variable (VL) domains to form scFv fragments. The linker sequences that are used to link VH and VL domains are well known to those with skill in the art and include the GGGGSGGGGSGGGGS [(G-iSty SEQ ID NO: 87] sequence that connect the C-terminus of the VH domain to the N- terminus of the VL domain. In some embodiments, the C-terminus of the VL domain can be connected to the N-terminus of the VH domain with similar linker sequences. ScFvs that bind to a cell surface receptor or other cell surface molecule can be isolated from libraries of scFvs using phage display, yeast display or other antibody display approaches. The targeting protein component of a macromolecule that targets AD AMTS 13 -specific antibodies could also include Fab fragments of an antibody that can be isolated from libraries of Fab fragments using phage display, yeast display etc. For nanobodies, scFvs and Fab fragments, affinities for binding to a cell surface receptor or cell surface molecule can be increased by randomly mutating residues in the complementarity determining regions (CDRs), or by using error-prone polymerase chain reaction, to generate libraries of mutated nanobodies or variable domains. Exemplary CDR residues that would be targeted are those in CDR3 of the light chain variable domain (residues 89-97; Kabat numbering) and CDR3 of the heavy chain variable domain (residues 95-102; Kabat numbering). These libraries can be displayed on phage or yeast and higher affinity variants selected using approaches known to those with skill in the art.

[0114] FIGURES 2H and 21 illustrate the antigen component at a terminal location of an antibody variable region, scFv or Fab fragment, optionally it may be located at a non-terminal location (FIGURE 2J). The antigen component may be fused to albumin, the antibody variable region. scFv or Fab fragment in any suitable manner, including attachment via a chemical reaction, attachment through a linker, or during formation of a single combined antigenantibody variable region, scFv or Fab fragment fusion protein.

[0115] A macromolecule that targets ADAMTS13-specific antibodies may also contain an antigen component fused to a targeting component that includes a protein other than an antibody or antibody fragment such as albumin, providing that this protein is configured to bind to a cell surface receptor or other cell surface molecule. Albumin is known to bind to FcRn (Chaudhury, C., Mehnaz, S., Robinson, J.M., Hayton, W.L., Pearl, D.K.. Roopenian, D.C., Anderson, C.L. (2003) The major histocompatibility complex-related Fc receptor for IgG (FcRn) binds albumin and prolongs its lifespan. J. Exp. Med., 197, 315-322; Sand, K.M.K., Bern, M., Nilsen, J., Noordzij, H.T., Sandlie, I., Andersen, J.T. (2015) Front. Immunol., 5, Article 582). For example, a macromolecule that targets ADAMTS 13 -specific antibodies includes the antigen component fused to albumin or an albumin fragment able to bind FcRn. The albumin or albumin fragment may be mutated or modified so that it binds with increased affinity to FcRn. For example, mutations can be inserted into the FcRn binding domain (Dili) of (human serum) albumin using error prone PCR followed by display of libraries of mutated albumin variants on yeast or phage, and selection of higher affinity variants. Alternatively, higher affinity variants can be generated by mutating residues at or near the albumimFcRn interface and either selecting or screening for albumin variants with increased binding affinity (for example, using approaches described in: US Patent No. 8,748.380 B2. Albumin variants, inventors: Plumridge, A., Sleep, D., Cameron, J., Sandlie, I., Andersen, J.T., Friis., E.P.; Bern, M., Nilsen, J., Ferrarese, M., Sand, K.M.K., Gjolberg, T.T., Lode, H.E., Davidson, R.J., Camire, R.M., Baekkevold, E.S., Foss, S., Grevys, A., Dalhus, B., Wilson, J., Hoydahl, L.S., Christianson. G.J., Roopenian, D.C., Schlothauer, T., Michaelson. T.E., Moe, M.C.. Lombardi, S., Pinotti, M., Sandlie, I., Branchini, A. Andersen, J.T. (2020) An engineered human albumin enhances half-life and transmucosal delivery when fused to protein-based biologies. Sci. Transl. Med., 14, eabb0580). Although the antigen component can be attached at a nonterminal location of albumin or an albumin fragment, it may instead be located at a terminal location. The antigen component may be fused to albumin or the albumin fragment in any suitable manner, including attachment via a chemical reaction, attachment through a linker, or during formation of a single combined antigen-FcRn-binding protein.

[0116] Similarly, the targeting component can be a carbohydrate, a carbohydrate derivative or small molecule that binds to ASGPR or mannose 6-phosphate receptor (e.g. CI-M6PR) that is attached to the antigen component using chemical methods known to those with skill in the art. In further embodiments, the antigen component can be expressed as a fusion protein and chemically conjugated to the carbohydrate, carbohydrate derivative or small molecule. Examples of such targeting components include, but are not limited to, those described previously in: International Publication No. WO 2022 / 157626 AL Degradation of extracellular targets, inventors: Allan, M., Bagdanoff, J., Barnes, D.W., Blankenship, J., Bradner, J., Clairmont, K., Granda, B., Junge, G., Smith, T., Traggiai, E., Wamcke, M.; International Publication No. WO 2020 / 132100 Al, Bifunctional molecules for lysosomal targeting and related composition and methods, inventors: Bertozzi. C.. Banik, S., Pedram, K., Ahn, G.; International Publication No. WO 2022 / 192478 Al, Bifunctional degraders of galactose- deficient immunoglobulins, inventors: Dubowchik, G.M., Spiegel, D., Caldwell, R.M.; US PatentNo. 12,128,105 B2, Molecular degraders of extracellular proteins, inventors: Caianiello, D., Deramon, E.. Spiegel, D.; International Publication No. WO 2025 / 035052 AL Molecular degraders for the treatment of IgA nephropathy, inventors: Kazmi erski, W.. Pracitto, R.. Dubowchik, G.M., Marcin, L.R., Bunin, A., Rossi, A.M., Iben, L.G., McGrath, K., Lee, S., Todd, M.; International Publication No. WO 2025 / 081173 A2, Bispecific molecular degraders of pathogenic proteins, inventors: Bunin, A., Car, B., Dow, M., Gardin, T., Lipson, S., Marcin, L.R., Mellott, D., Murray. S., Pirman, D., Velaparthi, U.; International Publication No. WO 2025 / 035040 Al, Lysosomal targeting bifunctional molecules for degradation of musclespecific kinase autoantibodies, inventors: Chen, T., Iwig, J., Lewis, J.G., Lieser, R.. Staben, S., Totten, S.M., Turtle, E.D..

[0117] FIGURES 2K and 2L are schematic representations of exemplary macromolecules that target ADAMTS13-specific antibodies including an antigen component attached to the C- terminus of an antibody with one or two Fab fragments that bind to a cell surface protein or cell surface molecule. The Fc fragment (Fc) in the antibody can be engineered to bind to FcRn with increased affinity and may be mutated so that it binds to Fc gamma receptors, particularly to activatory FcyRs, and complement with very low or no detectable binding affinity . In order to avoid antibody homodimers in which both Fc fragments have a fused antigen component, the macromolecules that target ADAMTS13-specific antibodies as shown in FIGURES 2K and 2L are designed with knobs-into-holes mutations and / or electrostatic steering mutations to promote heterodimer formation, so there is only one antibody heavy chain per antibody molecule with the attached antigen component. FIGURES 2M and 2N are schematic representations of exemplary macromolecules that comprise scFv fragments that bind to a cell surface protein or cell surface receptor and are attached to the C- or N-termini of the Fc fragment, and the antigen component is attached to the N- or C-termini, respectively, of the Fc fragment.

[0118] For the embodiments shown in FIGURES 20, 2P and 2Q and 2R, tw o different antigen components could be attached to the N- or C-termini of the Fc fragment, or if only one Fab fragment or scFv fragment is present, three different antigen components could be attached. For the embodiments shown in FIGURES 2K, 2M, 2N, 20, 2Q and 2R, both Fab fragments or scFv fragments may bind to the same cell surface protein or other cell surface molecule; alternatively, they could bind to two or more different cell surface proteins or molecules.

[0119] FIGURE 2S is a schematic representation of an exemplary' macromolecule that targets ADAMTS 13-specific antibodies including an antigen component attached to the N-terminus of an Fc fragment. In the example shown in FIGURE 2S, protein or protein fragments that bind to a cell surface receptor or cell surface molecule are attached to the C-terminus of the Fc fragment. For example, the protein or protein fragment may be the C2A domain of synaptotagmin that binds to phosphatidylserine (PS). The Fc fragment can also be engineered to bind to FcRn or inhibitory FcyRIIb with increased affinity and may be mutated so that it binds to activatory Fc gamma receptors and complement with reduced binding affinity. The macromolecule that targets ADAMTS13-specific antibodies as shown in FIGURE 2S is designed with knobs-into-holes mutations and / or electrostatic steering mutations to promote heterodimer formation, so there is only one Fc with one Fc-antigen. In FIGURE 2S, both Fc fragments have proteins or protein fragments that bind to the cell surface protein or other cell surface molecule fused to them; alternatively, only one such protein or protein fragment may be present. In the exemplary macromolecule that targets ADAMTS13-specific antibodies shown in FIGURE 2T. the antigen component and protein or protein fragments that bind to a cell surface receptor or cell surface molecule are fused to the C- and N-termini of the Fc fragments, respectively. The Fc component is similar to that described for the exemplary macromolecule that targets ADAMTS 13 -specific antibodies shown in FIGURE 2S.

[0120] As shown in FIGURE 2U, in an exemplary macromolecule that targets ADAMTS 13- specific antibodies, two molecules of the same antigen component may be attached to Fc fragment at N-terminal or other locations. This exemplary macromolecule that targets ADAMTS 13-specific antibodies is a homodimer that contains mutations to enhance binding to FcRn or FcyRIIb, and does not contain knobs-into-holes and / or electrostatic steering mutations.

[0121] FIGURE 2V is a schematic representation of exemplary macromolecule that targets ADAMTS 13-specific antibodies comprising two molecules of the same antigen component attached to the N-termini of an Fc fragment. In the exemplary embodiment shown in FIGURE 2V, protein or protein fragments that bind to a cell surface receptor or cell surface molecule are attached to the C-terminus of the Fc fragment. This exemplary macromolecule that targets ADAMTS 13-specific antibodies is a homodimer and does not contain knobs-into-holes and / or electrostatic steering mutations. In FIGURE 2V, the homodimeric Fc fragment has proteins or protein fragments that bind to the cell surface protein or other cell surface molecule fused to both polypeptide chains, but in other embodiments, only one such protein or protein fragment may be present.

[0122] For macromolecules that target ADAMTS 13 -specific antibodies, similar principles to those used in the examples shown in FIGURES 2 A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 21, 2J, 2K, 2L, 2M, 2N, 20, 2P, 2Q, 2R, 2S, 2T, 2U and 2V may be applied to other macromolecules. In the examples shown in FIGURES 2A. 2B, 2C, 2D, 2E, 2F, 2G, 2K, 2L, 2M, 2N, 20, 2P, 2Q, 2R. 2S and 2T. the macromolecule that targets ADAMTS 13 -specific antibodies has two antibody Fc fragments that are engineered with knobs-into-holes mutations and / or electrostatic steering mutations to drive the formation of heterodimers comprising one antigen linked to one Fc fragment and one Fc fragment with no antigen attached. Other embodiments shown in FIGURES 2D, 2E, 2F, 2G, 21, 20, 2P, 2Q, 2R, 2U and 2V can include two or more antigen components that may be different or the same. The Fc fragment can be further engineered to bind to FcRn with increased affinity at near-neutral pH, which may be greater than 6.8 and less than 7.5, (FIGURES 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2U and 2V) or connected to one or more proteins, scFv fragments, Fab fragments or other molecules, including a small molecule or carbohydrate, that target one or more cell surface receptors or molecules (FIGURES 2H, 21 and 2J). The Fc fragments in the examples shown in FIGURES 2K, 2L, 2M. 2N. 20, 2P, 2Q, 2R. 2S and 2T) can also be engineered to bind with higher affinity to FcRn so that they target both FcRn and one or more cell surface receptors or molecules.

[0123] Albumin binds more strongly to FcRn at acidic pH than at neutral pH. However, albumin molecules may also be modified to alter their binding affinities at near-neutral or endosomal pH to encourage degradation of the target antigen-specific antibody. Similarly, antibody variable region FcRn-binding proteins may be affected by pH in a manner specific to that protein, but they may still be modified to alter their binding affinities at near-neutral or endosomal pH to encourage degradation of the target antigen-specific antibody. These FcRn- binding proteins can be isolated from libraries of immunoglobulin variable domains. scFv [VH:VL heterodimers in which VH and VL domains are connected to each other by linker peptides such as GGGGSGGGGSGGGGS, (G4S)s, SEQ ID NO: 87] or Fab fragments using phage display, yeast display or other technologies known to those with skill-in-the-art. These libraries can either be derived from naturally occurring antibody variable genes, or can be generated using approaches that result in 'semi-synthetic’ libraries wherein complementarity determining regions (CDRs) are produced using randomized oligonucleotide sequences. Further increases to their affinities can be achieved by, for example, inserting random mutations in the CDRs using error-prone PCR followed by selection using phage display or yeast display. Exemplar}' CDR residues that would be targeted are those in CDR3 of the light chain variable domain (residues 89-97; Kabat numbering) and CDR3 of the heavy chain variable domain (residues 95-102; Kabat numbering). Similar methods can be used to isolate antibody -based proteins or scaffold-based proteins that bind to other cell surface receptors / molecules.

[0124] A macromolecule that targets ADAMTS13-specific antibodies may include any targeting component that is configured to specifically bind to a receptor or other molecule on the cell surface. The targeting component is fused directly or indirectly (e g., via a linker) to an antigen component (i.e. one or more domains of ADAMTS13, one or more fragments of ADAMTS13 or an ADAMTS13 mimetic), where the antigen component binds to a ADAMTS 13-specific antibody. Accordingly, a macromolecule that targets ADAMTS13- specific antibodies can include more than one antigen component, wherein each macromolecule that targets ADAMTS 13 -specific antibodies has only one molecule of each antigen component. If the targeting protein contains an immunoglobulin-derived Fc fragment, the Fc region can be mutated so that it does not bind, or binds at substantially reduced levels, to Fc gamma receptors (particularly activatory FcyRs) and complement, or binds with increased affinity to the inhibitory receptor, FcyRIIb. Several different possible configurations of a macromolecule that targets ADAMTS 13-specific antibodies are shown in FIGURE 2A-V; these are shown as examples and are not limiting, since multiple other configurations can also be envisaged by those with skill in the art.

[0125] For example, a macromolecule that targets ADAMTS 13-specific antibodies can have variations in the number of targeting domains or antibody fragments (e.g. Fab fragments or scFv fragments) (FIGURE 2). These targeting domains or antibody fragments can be linked to immunoglobulin Fc fragments, whereas in others, the targeting domains or antibody fragments may be linked to each other; the antigen and antibody fragments can be fused to Fc fragments or each other in different orientations (FIGURE 2); a macromolecule that targets ADAMTS 13- specific antibodies can include linker sequences that vary in length and composition between the fusion proteins, domains or fragments e.g. IEGRMD (SEQ ID NO: 88). GS, or GGGGS (SEQ ID NO: 85) or 2-3 repeats of this linker; antigen mimetics such as small molecules or peptides can be used; the Fc fragment in a macromolecule that targets ADAMTS 13 -specific antibodies may be mutated so that it has substantially reduced binding affinity for (activatory ) Fc gamma receptors, complement, and increased affinity for binding to FcRn; the Fc may be mutated so that it has increased affinity for the inhibitory' Fc receptor, FcyRIIb. The Fc fragments of a macromolecule that targets ADAMTS 13-specific antibodies may have mutations such as knobs-into-holes and / or electrostatic steering mutations so that heterodimers of Fc fragments are formed.

[0126] Additional embodiments can comprise targeting components that are polynucleotides such as ribonucleic acids or deoxyribonucleic acids, polypeptides, polysaccharides, lipids, amino acids, peptides, carbohydrates, carbohydrate derivatives and / or other small or large molecules and / or polymers identifiable by skilled persons in the art upon reading of the present disclosure. Such targeting components can be connected to the antigen component of the macromolecule that targets ADAMTS 13-specific antibodies using methods known to those with skill in that art that are, for example, described in the following: International Publication No. WO 2022 / 157626 Al, Degradation of extracellular targets, inventors: Allan, M., Bagdanoff, J., Barnes, D.W., Blankenship, J., Bradner, J., Clairmont, K., Granda, B., Junge, G., Smith, T., Traggiai, E., Wamcke, M.; International Publication No. WO 2022 / 192478 Al, Bifunctional degraders of galactose-deficient immunoglobulins, inventors: Dubowchik, G.M., Spiegel, D., Caldwell, R.M.; US Patent No. 12.128,105 B2, Molecular degraders of extracellular proteins, inventors: Caianiello. D., Deramon. E., Spiegel, D.; International Publication No. WO 2025 / 035052 Al, Molecular degraders for the treatment of IgA nephropathy, inventors: Kazmierski, W., Pracitto, R., Dubowchik, G.M., Marcin, L.R., Bunin, A., Rossi, A.M., Iben, L.G., McGrath, K , Lee. S., Todd, M.; International Publication No. WO 2025 / 081173 A2, Bispecific molecular degraders of pathogenic proteins, inventors: Bunin. A., Car, B., Dow, M., Gardin, T., Lipson, S., Marcin, L.R., Mellott, D., Murray, S., Pirman, D., Velaparthi, U.; International Publication No. WO 2025 / 035040 Al, Lysosomal targeting bifunctional molecules for degradation of muscle-specific kinase autoantibodies, inventors: Chen, T.. Iwig. J., Lewis, J.G.. Lieser, R., Staben, S., Totten, S.M., Turtle, E.D..

[0127] In several examples described herein, the macromolecule that targets AD AMTS 13- specific antibodies can be a heterodimer of fusion proteins comprising the amino acid sequences of SEQ ID NO: 2 plus SEQ ID NO: 4, SEQ ID NO: 2 plus SEQ ID NO: 5, SEQ ID NO: 2 plus SEQ ID NO: 6, SEQ ID NO: 2 plus SEQ ID NO: 7, SEQ ID NO: 1 plus SEQ ID NO: 8, SEQ ID NO: 9 plus SEQ ID NO: 10. SEQ ID NO: 11 plus SEQ ID NO: 12, SEQ ID NO: 13 plus SEQ ID NO: 14, SEQ ID NO: 3 plus SEQ ID NO: 15, SEQ ID NO: 3 plus SEQ ID NO: 16, SEQ ID NO: 3 plus SEQ ID NO: 17, SEQ ID NO: 2 plus SEQ ID NO: 18, SEQ ID NO: 19 plus SEQ ID NO: 21 plus SEQ ID NO: 22, SEQ ID NO: 19 plus SEQ ID NO: 21 plus SEQ ID NO: 23, SEQ ID NO: 20 plus SEQ ID NO: 21 plus SEQ ID NO: 22, SEQ ID NO: 20 plus SEQ ID NO: 21 plus SEQ ID NO: 23, SEQ ID NO: 2 plus SEQ ID NO: 24, SEQ ID NO: 18 plus SEQ ID NO: 25, SEQ ID NO: 4 plus SEQ ID NO: 25, SEQ ID NO: 6 plus SEQ ID NO: 25, SEQ ID NO: 38 plus SEQ ID NO: 25, SEQ ID NO: 8 plus SEQ ID NO: 25, SEQ ID NO: 33 plus SEQ ID NO: 25, SEQ ID NO: 34 plus SEQ ID NO: 25. SEQ ID NO: 37 plus SEQ ID NO: 25. SEQ ID NO: 26 plus SEQ ID NO: 27. SEQ ID NO: 28 plus SEQ ID NO: 29. SEQ ID NO: 2 plus SEQ ID NO: 30, SEQ ID NO: 31 plus SEQ ID NO: 32, SEQ ID NO: 1 plus SEQ ID NO: 33, SEQ ID NO: 1 plus SEQ ID NO: 34, SEQ ID NO: 8 plus SEQ ID NO: 35, SEQ ID NO: 33 plus SEQ ID NO: 35, SEQ ID NO: 34 plus SEQ ID NO: 35. SEQ ID NO: 37 plus SEQ ID NO: 35. SEQ ID NO: 4 plus SEQ ID NO: 35, SEQ ID NO: 6 plus SEQ ID NO: 35, SEQ ID NO: 18 plus SEQ ID NO: 35, SEQ ID NO: 38 plus SEQ ID NO: 35, SEQ ID NO: 1 plus SEQ ID NO: 36. SEQ ID NO: 1 plus SEQ ID NO: 37, SEQ ID NO: 2 plus SEQ ID NO: 38, SEQ ID NO: 20 plus SEQ ID NO: 47, SEQ ID NO: 20 plus SEQ ID NO: 48, SEQ ID NO: 20 plus SEQ ID NO: 49, SEQ ID NO: 20 plus SEQ ID NO: 50, SEQ ID NO: 20 plus SEQ ID NO: 51, SEQ ID NO: 20 plus SEQ ID NO: 52, SEQ ID NO: 47 plus SEQ ID NO: 53, SEQ ID NO: 48 plus SEQ ID NO: 53, SEQ ID NO: 49 plus SEQ ID NO: 53, SEQ ID NO: 50 plus SEQ ID NO: 53, or any of the heterodimers described in Table 1. or homologs thereof.

[0128] The macromolecule that targets ADAMTS13-specific antibodies can be a fusion protein comprising an amino acid sequence having at least 50% identity with SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34. SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45, SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, SEQ ID NO: 53, SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56. SEQ ID NO: 57. SEQ ID NO: 58. SEQ ID NO: 59. SEQ ID NO: 60. SEQ ID NO: 61, SEQ ID NO: 62, SEQ ID NO: 63, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 67, SEQ ID NO: 68, SEQ ID NO: 69, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 72, SEQ ID NO: 73, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 77, SEQ ID NO: 78, SEQ ID NO: 79. SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 82, or SEQ ID NO: 83, or a homolog thereof.

[0129] As used herein, "sequence identity" or "identity" in the context of two nucleic acid or polypeptide sequences makes reference to the nucleotide bases or residues in the two sequences that are the same when aligned for maximum correspondence over a specified comparison window. When a percentage of sequence identity or similarity is used in reference to proteins, it is recognized that residue positions which are not identical often differ by conservative amino acid substitutions, where amino acid residues are substituted with a functionally equivalent residue of the amino acid residues with similar physiochemical properties and therefore do not change the functional properties of the molecule. A functionally equivalent residue of an amino acid used herein typically refers to other amino acid residues having physiochemical and stereochemical characteristics substantially similar to the original amino acid. The physiochemical properties include water solubility (hydrophobicity or hydrophilicity), dielectric and electrochemical properties, physiological pH, partial charge of side chains (positive, negative or neutral) and other properties identifiable to a person skilled in the art. The stereochemical characteristics include spatial and conformational arrangement of the amino acids and their chirality. For example, glutamic acid is considered to be a functionally equivalent residue to aspartic acid in the sense of the current disclosure. Tyrosine and tryptophan are considered as functionally equivalent residues to phenylalanine. Arginine is considered as a functionally equivalent residue to lysine.

[0130] A person skilled in the art would understand that similarity between sequences is ty pically measured by a process that includes the steps of aligning the two polypeptide or polynucleotide sequences to form aligned sequences, then detecting the number of matched characters, i.e. characters similar or identical between the two aligned sequences, and calculating the total number of matched characters divided by the total number of aligned characters in each polypeptide or polynucleotide sequence, including gaps. The similarity result is expressed as a percentage of identity.

[0131] As used herein, "percentage of sequence identity7" means the value determined by comparing two optimally aligned sequences over a comparison window, wherein the portion of the polynucleotide sequence in the comparison window may include additions or deletions (gaps) as compared to the reference sequence (which does not include additions or deletions) for optimal alignment of the two sequences. The percentage is calculated by determining the number of positions at which the identical nucleic acid base or amino acid residue occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison, and multiplying the result by 100 to yield the percentage of sequence identity.

[0132] As used herein, "reference sequence" is a defined sequence used as a basis for sequence comparison. A reference sequence may be a subset or the entirety7of a specified sequence; for example, as a segment of a full-length protein or protein fragment. A reference sequence can be, for example, a sequence identifiable in a database such as GenBank and UniProt and others identifiable to those skilled in the art.

[0133] As understood by those skilled in the art, determination of percent identity between any two sequences can be accomplished using a mathematical algorithm. Computer implementations of suitable mathematical algorithms can be utilized for comparison of sequences to determine sequence identity. Such implementations include, but are not limited to: CLUSTAL, ALIGN, GAP, BESTFIT, BLAST, FASTA, among others identifiable by skilled persons in the art.

[0134] For example, a macromolecule that targets ADAMTS 13 -specific antibodies according to the present disclosure can have an amino acid sequence having at least 50% sequence identity, at least 80%, at least 90%, at least 95% sequence identity compared to SEQ ID NO: 1 , SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19. SEQ ID NO: 20. SEQ ID NO: 21. SEQ ID NO: 22, SEQ ID NO: 23. SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 43, SEQ ID NO: 44, SEQ ID NO: 45. SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, or SEQ ID NO: 53, SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 57, SEQ ID NO: 58, SEQ ID NO: 59, SEQ ID NO: 60, SEQ ID NO: 61, SEQ ID NO: 62, SEQ ID NO: 63, SEQ ID NO: 64, SEQ ID NO: 65. SEQ ID NO: 66, SEQ ID NO: 67, SEQ ID NO: 68, SEQ ID NO: 69, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 72, SEQ ID NO: 73, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 77, SEQ ID NO: 78, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 81, SEQ ID NO: 82, or SEQ ID NO: 83.

[0135] As shown in the examples below, a macromolecule that targets ADAMTS 13-specific antibodies is able to selectively deplete ADAMTS 13-specific antibodies with specificity for their fused antigen. As shown in the examples below, a macromolecule that targets ADAMTS 13-specific antibodies is able to selectively deplete the target ADAMTS 13-specific antibodies without adversely affecting the levels of antibodies of other specificities or eliciting an adverse immune reaction. These findings stand in contrast to other approaches, in which treatment results in depletion of total IgGs. through the use of FcRn inhibitors or antibodies that destroy B-cells. Such approaches adversely affect antibodies of non-targeted specificities or B-cell function because they lack the selectivity provided by the macromolecule that targets ADAMTS 13-specific antibodies. A macromolecule that targets ADAMTS 13 -specific antibodies may be administered in any way able to deliver the antibodies to cells expressing the receptor or other molecule on the cell surface that is being targeted, such as via injection, particularly intravenous, subcutaneous or intramuscular injection, or injection into a tissue targeted by the antigen-specific antibodies that are to be depleted. A macromolecule that targets ADAMTS 13-specific antibodies can also be expressed in cells that have been genetically engineered to contain expression constructs encoding the macromolecule. In particular, cells can be genetically engineered by introducing expression constructs that encode the macromolecule that targets ADAMTS 13 -specific antibodies that include proteins or peptides that allow secretion of the macromolecule from the engineered cells in situ.

[0136] A macromolecule that targets ADAMTS 13 -specific antibodies may be administered in an amount that does not block every targeted receptor / cell surface molecule, and therefore does not adversely affect the function of the cell surface receptor / molecule. The dose of the macromolecule that targets ADAMTS 13-specific antibodies used may be similar to the amount of ADAMTS 13 -specific antibody being targeted for clearance. In addition, the macromolecule that targets ADAMTS 13-specific antibodies can be designed so that it does not compete with the natural ligand of the cell surface receptor or cell surface molecule for binding, for example, by using nanobodies (VHH) that bind to FcRn at a site that does not overlap with the IgG binding site (for example as described in Andersen, J.T., Gonzalez-Pajuelo, M., Foss, S., Landsverk, O.J.B., Pinto, D., Szyroki, A., de Haard, H.J., Saunders, M., Vanlandshoot, P., Sandlie, I. (2012) Selection of nanobodies that target human neonatal receptor. Sci. Rep., 3, 1118). In addition, the macromolecule that targets ADAMTS 13 -specific antibodies may remove less than 20%, less than 10%, less than 5%, or less than 1%, of non-targeted antibodies in the circulation or in a tissue targeted by the antigen-specific antibody that is to be depleted. Retention of non-targeted antibodies during and after treatment with the macromolecule may be important in normal immune function and the avoidance of infections, among other effects as described herein.

[0137] A macromolecule that targets ADAMTS 13 -specific antibodies may be repeatedly dosed at, for example, daily, twice weekly, or weekly intervals to achieve the desired lowering of ADAMTS 13-specific antibody levels. The levels of ADAMTS 13-specific antibody can be determined by using enzyme-linked immunosorbent assays (ELISAs) to analyze serum samples. Alternatively, other methods that are well known to those with skill in the art can be used.

[0138] A macromolecule that targets ADAMTS 13-specific antibodies may be administered by dosing in amounts and at frequencies sufficient to deplete at least 50%. at least 80% or at least 90% of the concentration of the AD AMTS 13-specific antibody in the circulation or in a tissue recognized by the ADAMTS13-specific antibody within one hour, two hours, five hours, 24 hours or 48 hours or longer of administration. The persistence of the macromolecule that targets ADAMTS13-specific antibodies in the body will be a determinant of how long it has activity in depleting ADAMTS13-specific antibodies. A macromolecule that targets ADAMTS13-specific antibodies can be designed to have a different in vivo half-life by the behavior of the cell surface receptor or cell surface molecule that it targets. The affinity' of the macromolecule that targets ADAMTS 13 -specific antibodies for this cell surface receptor or cell surface molecule can also be modified, using mutagenesis and approaches known to those with skill in the art, to result in a macromolecule that targets ADAMTS 13 -specific antibodies with a modified half-life in the circulation and / or tissues.

[0139] EMBODIMENTS

[0140] The invention may comprise or consist of any one of the following embodiments, or any combination thereof.

[0141] 1. A macromolecule that targets ADAMTS 13 -specific antibodies, comprising: a targeting component configured to specifically bind to a cell surface receptor or other cell surface molecule; and an antigen component fused directly or indirectly to the targeting component, wherein the antigen component comprises at least part of a spacer (S) domain of ADAMTS 13 and is configured to specifically bind to an ADAMTS 13-specific antibody.

[0142] 2. The macromolecule of embodiment 1, wherein the antigen component further comprises at least part of a Cys-rich (C) domain of ADAMTS 13. 3. The macromolecule of embodiment 1 or embodiment 2, wherein the antigen component further comprises at least part of a first thrombospondin type 1 (TSP1) repeat (T) domain of ADAMTS13.

[0143] 4. The macromolecule of any one of embodiments 1-3. wherein the antigen component comprises substantially the entirety' of the T, C and S domains of ADAMTS13.

[0144] 5. The macromolecule of any one of embodiments 1-4, wherein the antigen component further comprises at least part of a disintegrin-like (D) domain of ADAMTS13.

[0145] 6. The macromolecule of any one of embodiments 1-5, wherein the antigen component further comprises at least part of a metalloprotease (M) domain of ADAMTS13.

[0146] 7. The macromolecule of any one of embodiments 1-6, wherein the antigen component further comprises at least part of a CUB1 domain of ADAMTS13.

[0147] 8. The macromolecule of any one of embodiments 1-7, wherein the antigen component further comprises at least part of a CUB2 domain of ADAMTS13.

[0148] 9. The macromolecule of any one of claims 1-8, wherein the targeting component comprises an immunoglobulin Fc fragment.

[0149] 10. The macromolecule of embodiment 9, wherein the immunoglobulin Fc fragment is modified to have substantially reduced binding affinity for Fc gamma receptors compared to an unmodified immunoglobulin Fc fragment.

[0150] 1 1. The macromolecule of embodiment 9 or embodiment 10, wherein the immunoglobulin Fc fragment comprises mutations L234S / L235T / G236R according to EU numbering.

[0151] 12. The macromolecule of any one of embodiments 9-11, wherein the immunoglobulin Fc fragment is modified to have substantially reduced binding affinity for complement Clq compared to an unmodified immunoglobulin Fc fragment. 13. The macromolecule of any one of embodiments 9-12, wherein the immunoglobulin Fc fragment is modified to have a higher binding affinity for FcRn at near-neutral pH than an unmodified immunoglobulin Fc fragment.

[0152] 14. The macromolecule of any one of embodiments 9-13, wherein the immunoglobulin Fc fragment comprises mutations M252Y / S254T / T256E / H433K / N434F according to EU numbering.

[0153] 15. The macromolecule of any one of embodiments 9-14, wherein the immunoglobulin Fc fragment is modified to have increased binding affinity’ for FcyRIIb compared to an unmodified immunoglobulin Fc fragment.

[0154] 16. The macromolecule of any one of embodiments 9-15, wherein the immunoglobulin Fc fragment comprises mutations selected from the group consisting of P238D, G237D / P271G / A330R, G237D / H268D / P271G / A330R, G236N / H268D / A330K, and

[0155] S267E / L328F according to EU numbering.

[0156] 17. The macromolecule of any one of embodiments 9-16, wherein the targeting component comprises a heterodimer of two immunoglobulin Fc fragments.

[0157] 18. The macromolecule of embodiment 17. wherein one immunoglobulin Fc fragment of the heterodimer is fused to the antigen component and the other immunoglobulin Fc fragment is not fused to the antigen component.

[0158] 19. The macromolecule of embodiment 17 or embodiment 18, wherein the heterodimer comprises knobs-into-holes mutations.

[0159] 20. The macromolecule of embodiment 19, wherein the knobs-into-holes mutations comprise T366W in one Fc fragment and T366S / L368A / Y407V in the other Fc fragment according to EU numbering. 21. The macromolecule of any one of embodiments 9-20, wherein the antigen component is fused to an N-terminus of the immunoglobulin Fc fragment.

[0160] 22. The macromolecule of any one of embodiments 9-21, wherein the antigen component is fused to a C-terminus of the immunoglobulin Fc fragment.

[0161] 23. The macromolecule of any one of embodiments 1-8, wherein the targeting component comprises albumin or an albumin fragment.

[0162] 24. The macromolecule of embodiment 23, wherein the albumin or albumin fragment is configured to specifically bind to FcRn.

[0163] 25. The macromolecule of any one of embodiments 1-24, wherein the targeting component comprises one or more antibody variable regions configured to specifically bind to the cell surface receptor or cell surface molecule.

[0164] 26. The macromolecule of embodiment 25, wherein the one or more antibody variable regions comprise at least one nanobody.

[0165] 27. The macromolecule of any one of embodiments 1-26, wherein the cell surface receptor or cell surface molecule is FcRn.

[0166] 28. The macromolecule of embodiment 27, wherein the targeting component can bind to FcRn with a dissociation constant of less than 10 pM at near-neutral pH.

[0167] 29. The macromolecule of any one of embodiments 1-26. wherein the cell surface receptor or cell surface molecule is a transferrin receptor.

[0168] 30. The macromolecule of any one of embodiments 1-26, wherein the cell surface receptor or cell surface molecule is an asialoglycoprotein receptor (ASGPR). 31. The macromolecule of embodiment 30, wherein the targeting component comprises an antibody or antibody fragment that specifically binds to ASGPR.

[0169] 32. The macromolecule of any one of embodiments 1-26, wherein the cell surface receptor or cell surface molecule is FcyRIIb.

[0170] 33. The macromolecule of any one of embodiments 1-26, wherein the cell surface receptor or cell surface molecule is CD 163.

[0171] 34. The macromolecule of any one of embodiments 1-26. wherein the cell surface receptor or cell surface molecule is a mannose 6-phosphate receptor.

[0172] 35. The macromolecule of any one of embodiments 1-26, wherein the cell surface receptor or cell surface molecule is phosphatidylserine.

[0173] 36. The macromolecule of embodiment 35, wherein the targeting component comprises a C2A domain of synaptotagmin 1.

[0174] 37. The macromolecule of any one of embodiments 1-36, wherein the targeting component comprises a carbohydrate or carbohydrate derivative configured to specifically bind to the cell surface receptor or cell surface molecule.

[0175] 38. The macromolecule of any one of embodiments 1-36. wherein the targeting component comprises a small molecule configured to specifically bind to the cell surface receptor or cell surface molecule.

[0176] 39. The macromolecule of any one of embodiments 1-38, wherein the antigen component is fused to the targeting component via a linker.

[0177] 40. The macromolecule of embodiment 39, wherein the linker comprises a glycine-serine linker, optionally a glycine-glycine-glycine-glycine-serine (GGGGS; SEQ ID NO: 85) linker peptide. 41. The macromolecule of any one of embodiments 1-40, further comprising a second antigen component that is different from the first antigen component.

[0178] 42. The macromolecule of any one of embodiments 1-41, wherein the second antigen component comprises one or more domains of ADAMTS13 different from those in the first antigen component.

[0179] 43. The macromolecule of any one of embodiments 1-42, wherein the macromolecule comprises an amino acid sequence having at least 90% sequence identity to a sequence selected from the group consisting of SEQ ID NO: 1 through SEQ ID NO: 83.

[0180] 44. The macromolecule of any one of embodiments 1-5, 9-22, or 25-43, wherein the macromolecule comprises a heterodimer of proteins having amino acid sequences of SEQ ID NO: 2 and SEQ ID NO: 4.

[0181] 45. The macromolecule of any one of embodiments 1-4, 9-22, or 25-43, wherein the macromolecule comprises a heterodimer of proteins having amino acid sequences of SEQ ID NO: 2 and SEQ ID NO: 18.

[0182] 46. The macromolecule of any one of embodiments 1-45, wherein the macromolecule has substantially reduced binding to von Willebrand Factor compared to full-length ADAMTS13.

[0183] 47. The macromolecule of embodiment 4, wherein the macromolecule has substantially reduced binding to von Willebrand Factor compared to a macromolecule comprising D. T, C and S domains of ADAMTS13.

[0184] 48. A method of depleting ADAMTS13-specific antibodies from a patient, comprising administering to the patient the macromolecule of any one of embodiments 1-47 in an amount sufficient to remove at least 50% of the ADAMTS13-specific antibodies from circulation in the patient. 49. The method of embodiment 48, wherein the macromolecule is administered in an amount sufficient to remove at least 80% of the ADAMTS13-specific antibodies from circulation in the patient.

[0185] 50. The method of embodiment 48 or embodiment 49, wherein the ADAMTS-13 specific antibodies are specific for the T, C or S domain of ADAMTS-13.

[0186] 51. The method of any one of embodiments 48-50, wherein the patient has immune-mediated thrombotic thrombocytopenic purpura (iTTP).

[0187] EXAMPLES

[0188] The following examples are provided to further illustrate specific embodiments of the disclosure. They are not intended to disclose or describe each and every aspect of the disclosure in complete detail and should not be so interpreted. Unless otherwise specified, designations of compositions are used consistently throughout these examples.

[0189] A summary of exemplary macromolecules that target ADAMTS13-specific antibodies, including their SEQ ID NOs, is presented in Tables 2 and 3.

[0190] Example 1; Expression, purification and characterization of exemplary macromolecules that bind to FcRn with increased affinity and target ADAMTS13-specific antibodies

[0191] Embodiments of macromolecules that bind to FcRn with increased affinity and target ADAMTS13-specific antibodies comprising one or more antigen components are shown in FIGURE 2A, 2B, 2C, 2D, 2E, 2F and 2G. These macromolecules comprise heterodimeric Fc fragments with mutations to eliminate interactions with human FcyRs and to enhance the binding affinity' to FcRn at near-neutral pH, which may be greater than 6.8 and less than 7.5. Heterodimer formation of the two Fc fragments is achieved by inserting knobs-inlo-holes' mutations in the CH3 domains.

[0192] FIGURE 3 shows a schematic representation of the domains of ADAMTS13, with the domains: M, D, T (also known as Tl), C, S, T2, T3, T4, T5, T6, T7, T8, CUB1 and CUB2.

[0193] Expression constructs to generate exemplary macromolecules that target ADAMTS13- specific antibodies (SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7. SEQ ID NO: 8, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17. SEQ ID NO: 18. SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQ ID NO: 30, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, or SEQ ID NO: 38) that bind to FcRn with increased affinity were made as follows: to express the polypeptide chain with one or more domains of ADAMTS13 fused to an engineered Fc fragment, the gene encoding one or more domains of ADAMTS13 were linked in frame to codons encoding linker peptides (e.g. GS, G4S) to codons encoding the C-terminus of the CH3 domain, or N-terminus of the hinge region, of a human IgGl -derived Fc fragment using standard molecular biology techniques (thereby encoding SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17. SEQ ID NO: 18. SEQ ID NO: 24. SEQ ID NO: 27. SEQ ID NO: 30, SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, or SEQ ID NO: 38). Mutations to ablate binding to FcyRs (L234S / L235T / G236R; L234A / L235A / P329G can be used as an alternative; EU numbering used for mutations), enhance binding to FcRn (MST- HN; M252Y / S254T / T256E / H433K / N434F; EU numbering) and generate ’knobs-into-holes’ (T366W; EU numbering) were inserted into the Fc fragment gene (thereby encoding SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 24, SEQ ID NO: 27, SEQ ID NO: 30, SEQ ID NO: 33. SEQ ID NO: 34. SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, or SEQ ID NO: 38). Codons encoding the mouse Ig leader peptide MGWSCIILFLVATATGVHS (SEQ ID NO: 89) were appended to the N-terminus of the Fc fragment gene, or of the antigen gene segment for antigens fused to the N-terminus of the Fc fragment gene. In further embodiments, different FcyR ablating mutations (L234A / L235A / D265S; EU numbering) were inserted into the Fc fragment gene (thereby encoding SEQ ID NO: 15, SEQ ID NO: 16, or SEQ ID NO: 17). For expression as heterodimers, Fc fragment genes with FcRn-enhancing mutations, in some cases with additional antigen components comprising ADAMTS13 domains attached (e g. CUB1, CUB2 domains; SEQ ID NO: 25, or SEQ ID NO: 35), and mutations to ablate FcyR binding (L234S / L235T / G236R or L234A / L235A / D265S; alternatively, L234A / L235A / P329G can be used; EU numbering used for mutations) were generated with complementary' knobs-into-holes mutations (T366S / L368A / Y407V: EU numbering) (thereby encoding SEQ ID NO: 1, SEQ ID NO: 2. SEQ ID NO: 3, SEQ ID NO: 25, or SEQ ID NO: 35). Further embodiments for exemplary FcRn-targeting macromolecules that target ADAMTS 13-specific antibodies are shown in Table 1. These embodiments can be made by combining the FcRn-targeting components (SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 26, SEQ ID NO: 61, SEQ ID NO: 65, SEQ ID NO: 68, SEQ ID NO: 69, SEQ ID NO: 73, SEQ ID NO: 76, SEQ ID NO: 77, or SEQ ID NO: 81) with one or more domains of ADAMTS13 (SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 57, SEQ ID NO: 58, SEQ ID NO: 59. or SEQ ID NO: 60) as N- or C-terminal fusion proteins, with different linkers (e.g. GS, G4S, SEQ ID NO: 85) using analogous methods to those described above.

[0194] Recombinant proteins were expressed in ExpiCHO cells (Life Technologies) following transient transfection with the ExpiCHO expression system kit (Life Technologies). The proteins were purified using protein A-Sepharose followed by size exclusion chromatography (SEC) in phosphate buffered saline (PBS). SDS-PAGE analyses for exemplary macromolecules that target ADAMTS 13 -specific antibodies (TTP 027 + TTP 078, TTP 061 + TTP 160, TTP 027 + TTP 168, TTP 027 + TTP 097, TTP 061 + TTP 146, TTP 061 + TTP 147; see Table 2 for corresponding SEQ ID NOs) are shown in FIGURE 4A, 4B, 4C, 4D and 4E. FIGURE 4F shows size exclusion analyses using a Superdex 200 Increase column for several of the exemplary macromolecules that target ADAMTS 13-specific antibodies (TTP 027 + TTP 168, TTP 061 + TTP 160, TTP 027 + TTP 078, TTP 027 + TTP 079; see Table 2 for corresponding SEQ ID NOs).

[0195] The FcRn-targeting macromolecules that target ADAMTS 13 -specific antibodies bind to recombinant (human IgGl / kappa) ADAMTS 13-specific antibodies and maintain a significantly higher binding affinity for FcRn at neutral pH and at an acidic pH due to the presence of the MST-HN mutations (M252Y, S254T, T256E, H433K, N434F; EU numbering).

[0196] Surface plasmon resonance experiments to analyze the interactions of recombinant macromolecules with ADAMTS 13-specific antibodies and human FcRn were carried out using a BIAcore T200 (GE Healthcare). For example, the binding of a macromolecule that targets ADAMTS 13-specific antibodies to two recombinant ADAMTS 13-specific antibodies (TTP- Tracerl and TTP_Tracer2, generated as chimeric human IgGl / kappa antibodies using standard methods and the VH and VL domain sequences of antibody 1-420 and antibody 1-431. respectively, described in: WO 2016 / 164468 A2, Human monoclonal antibodies to ADAMTS 13 and uses thereof, inventors: Siegel, D.L., Kacir, S., Ostertag, E., Zheng, X.L.) was analyzed by injecting a range of concentrations (0.25-40 nM of macromolecule over immobilized antibodies (coupled at - 1051 RU for 1-420 and - 669 RU for 1-431 on flow cells of a CM5 sensor chip) in PBS (pH 7.4) plus 0.01% v / v Tween-20 at a flow rate of 10 pl / minute. Flow cells were regenerated following each injection and dissociation phase using 25 mM NaOH. Data were zero-adjusted and background-subtracted (background obtained by injection over a flow cell coupled with buffer only during coupling reaction). FIGURE 5A shows representative sensorgrams for the binding of a macromolecule that targets ADAMTS13- specific antibodies (TTP 027 + TTP 168; see Table 2 for corresponding SEQ ID NOs) to antibodies 1-420 and 1-431 (labeled Tracer 1 and Tracer 2 in FIGURE 5A). The equilibrium dissociation constants for the interactions are 1.15 nM (1-420; TTP_Tracerl) and 1.12 nM (1- 431; TTP_Tracer2).

[0197] Binding of an exemplary macromolecule that targets ADAMTS 13 -specific antibodies to recombinant human FcRn was analyzed by injecting a range of concentrations (0.05-200 nM) of macromolecule over immobilized FcRn (coupled at ~ 616 RU on a CM5 sensor chip) in PBS (pH 6.0) plus 0.01% v / v Tween-20 at a flow rate of 10 pl / minute. Flow cells were regenerated following each injection and dissociation phase using 0.1 M NaCl, 0.1 M sodium bicarbonate, pH 8.5. Data were zero-adjusted and background-subtracted (background obtained by injection over a flow cell coupled with buffer only during coupling reaction). FIGURE 5B shows sensorgrams for the binding of a macromolecule that targets ADAMTS 13- specific antibodies (TTP 027 + TTP 168; see Table 2 for corresponding SEQ ID NOs) to FcRn at pH 6.0. The equilibrium dissociation constant for the interaction is 1 nM (note that this is an apparent dissociation constant due to avidity effects with immobilized FcRn), indicating much stronger binding to human FcRn than observed for human IgGl or Fc fragments that are not engineered for increased affinity for human FcRn (for example, see Zhou, J., Mateos, F., Ober, R.J., Ward, E.S. (2005) Conferring the binding properties of the mouse MHC class I-related receptor, FcRn, onto the human ortholog by sequential rounds of site-directed mutagenesis. J. Mol. Biol., 345, 1071-1081).

[0198] Mutations to increase the affinity' for FcRn, such as MST-HN, were identified using the following approach: residues in proximity to amino acids (e.g. 253, 435) that are known to be essential for FcRn binding were randomly mutated in an Fc fragment gene and the libraries of mutated Fc fragments displayed on phage. Fc fragments with increased binding affinity for FcRn were selected using phage display technology (Ghetie, V., Popov, S., Borvak, J., Radu, C., Matesoi, D., Medesan, C., Ober, R.J., Ward, E.S. (1997) Increasing the serum persistence of an IgG fragment by random mutagenesis. Nature Biotech., 15, 637-640; Dall’Acqua, W.F., Woods, R.M., Ward. E.S., Palaszynski, S.R., Patel, N.K., Brewah, Y.A., Wu, H., Kiener. P.A., Langermann, S. (2002) Increasing the affinity of a human IgGl for the neonatal receptor: biological consequences, J. Immunol., 169, 5171-5180). Alternatively, these residues can be mutated to every other possible amino acid and Fc fragments with higher affinity for FcRn identified using methods such as ELISA or surface plasmon resonance binding analyses.

[0199] Binding of an exemplary macromolecule that targets ADAMTS 13 -specific antibodies to recombinant A2 domain of VWF was analyzed by injecting a range of concentrations (0.25- 400 nM) of macromolecule over immobilized A2 domain (coupled at ~ 241 RU on a CM5 sensor chip) in PBS (pH 7.4) plus 0.01% v / v Tween-20 at a flow rate of 10 pl / minute. Flow cells were regenerated following each injection and dissociation phase using 0.1 M NaCl, 0.1 M sodium bicarbonate, pH 10. FIGURE 6 shows analyses of the interaction of an exemplary macromolecule that targets ADAMTS 13-specific antibodies with the A2 domain of VWF. The exemplary macromolecule comprises the T, C and S domains of ADAMTS 13 (TTP 027 + TTP_1 8; see Table 2 for corresponding SEQ ID NOs), and has substantially reduced binding activity compared with that of a different macromolecule comprising D, T, C and S domains (TTP_027 + TTP_078; see Table 2 for corresponding SEQ ID NOs). Consequently, the removal of the D domain has the desirable effect of decreasing the binding of the macromolecule to VWF.

[0200] Size exclusion analyses indicate that exemplary' recombinant macromolecules that target ADAMTS 13 -specific antibodies (TTP 061 + TTP 160, TTP 027 + TTP 168, TTP 027 + TTP 078; see Table 2 for corresponding SEQ ID NOs) do not aggregate following incubation in phosphate buffered saline when incubated for 5 or 14 days at 37°C (FIGURES 7A, 7B and 7C).

[0201] Example 2: Expression and purification of macromolecules that target ADAMTS 13-specific antibodies and the internalizing receptors, FcyRIIb and ASGPR

[0202] Expression constructs to generate the exemplary macromolecules that target ADAMTS 13-specific antibodies and bind with increased affinity' to the inhibitory receptor, FcyRIIb, were made as follows: to express the polypeptide chain with one or more domains of ADAMTS 13, or a peptide thereof, fused to an engineered Fc fragment, the genes encoding the following domains of ADAMTS 13 were linked in frame to codons encoding linker peptides (e.g. GS, G4S; other linker sequences can also be used) to codons encoding the C-terminus of the CH3 domain of a human IgGl -derived Fc fragment using standard molecular biology techniques: D, T, C and S (thereby encoding SEQ ID NO: 10, SEQ ID NO: 12, or SEQ ID NO: 14) and T, C and S (thereby encoding SEQ ID NO: 29, SEQ ID NO: 31). Mutations to enhance binding to FcyRIIb (G237D / P271G / A330R. G237D / H268D / P271G / A330R,

[0203] G236N / H268D / A330K, S267E / L328F, P238D; EU numbering) and generate ‘knobs-into- holes’ (T366W; EU numbering) were inserted into the Fc fragment gene. Codons encoding the mouse Ig leader peptide MGWSCIILFLVATATGVHS (SEQ ID NO: 89) were appended to the N-terminus of the Fc fragment gene. For expression as heterodimers, Fc fragment genes with FcyRIIb-enhancing mutations were generated with complementary knobs-into-holes mutations (T366S / L368A / Y407V; EU numbering) (thereby encoding SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 28, or SEQ ID NO: 32).

[0204] Further embodiments for exemplary FcyRIIb- targeting macromolecules that target ADAMTS13-specific antibodies are shown in Table 1. These embodiments can be made by combining the FcyRIIb-targ eting components (SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 28, SEQ ID NO: 32, SEQ ID NO: 62, SEQ ID NO: 63, SEQ ID NO: 64. SEQ ID NO: 66, SEQ ID NO: 67, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 78, SEQ ID NO: 79, SEQ ID NO: 80, SEQ ID NO: 82, or SEQ ID NO: 83) with one or more domains of ADAMTS13 (SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, SEQ ID NO: 57. SEQ ID NO: 58. SEQ ID NO: 59, or SEQ ID NO: 60) as N- or C-terminal fusion proteins, with different linkers (e.g. GS, G4S, SEQ ID NO: 85) using analogous methods to those described above.

[0205] To generate macromolecules that target ADAMTS13-specific antibodies that bind to the asialoglycoprotein receptor (ASGPR). the following expression constructs were made: to express the polypeptide chain with one or more domains of ADAMTS13. the gene encoding one or more domains of AD AMTS 13 was linked in frame with codons encoding linker peptides (e.g. GS, G4S) to the C-terminal codon of the CH3 region of a human IgGl / kappa antibody comprising VH and VL domain genes of the 51A12 or 51A12_A6 antibody (SEQ ID NO: 4 for VH; SEQ ID NO: 2 or SEQ ID NO: 44 for VL in: WO 20I4 / 023709 / A1; ASGPR antibodies and uses thereof; inventors: Hofer, T., Ji, C., Moessner, E., Umana, P) (thereby encoding heavy chain construct SEQ ID NO: 21, and light chain constructs SEQ ID NO: 22 and SEQ ID NO: 23). Mutations to ablate binding to FcyRs (L234S / L235T / G236R, alternatively L234A / L235A / D265S or L234A / L235A / P329G can be used; EU numbering) and generate ‘knobs-into-holes’ (T366W; EU numbering) were inserted into the Fc fragment gene (SEQ ID NO: 21). For expression as heterodimers, heavy chain or Fc fragment genes with mutations to ablate FcyR binding (e.g. L234S / L235T / G236R, alternatively L234A / L235A / D265S or L234A / L235A / P329G can be used; EU numbering) were generated with complementary knobs-into-holes mutations (T366S / L368A / Y407V; EU numbering) (thereby encoding SEQ ID NO: 19, or SEQ ID NO: 20). For additional embodiments, genes encoding one or more domains of AD AMTS 13 that are different to those appended to the first CH3 domain are linked in frame with codons encoding linker peptides (e.g. GS, G4S) to the sequence encoding the second CH3 domain of the antibody.

[0206] Recombinant proteins were expressed in ExpiCHO cells (Life Technologies) following transient transfection with the ExpiCHO expression system kit (Life Technologies). The proteins were purified using protein A-Sepharose followed by size exclusion chromatography (SEC) in phosphate-buffered saline (PBS) (FIGURE 8; data shown for TTP 108 + TTP 109, TTP 112 + TTP 113 and TTP 247 + TTP 248; see Table 2 for corresponding SEQ ID NOs).

[0207] Example 3; Effects of Fc mutations on FcyR and Clq binding of exemplary macromolecules that target ADAMTS13-specific antibodies

[0208] The effects of mutations to reduce binding to FcyRs and complement Clq of exemplary macromolecules that target ADAMTS13-specific antibodies is shown in FIGURES 9A, 9B and 9C. To analyze the binding of FcyRs, wells of ELISA plates were coated with macromolecule or, as a control, wild type human IgGl. Following washing with PBS containing 0.05% v / v Tween 20 (PBST) and PBS, wells were incubated in 4% (w / v) skimmed milk in PBS. Wells were then w ashed in PBST and PBS, and pre-incubated mixtures of biotinylated FcyR (CD16a, CD32a or CD64; from Sino Biological) with neutravidin-horse radish peroxidase (HRP) to form multivalent complexes in 1% (w / v) skimmed milk in PBST were added to the wells, and following incubation, wells were washed with PBST followed by PBS. This was followed by addition of TMB substrate (e.g. BioFX® TMB One Component HRP Microwell Substrate) to detect bound neutravidin-HRP.

[0209] To assess binding of the macromolecules that target ADAMTS 13 -specific antibodies to complement Clq, wells of ELISA plates were coated with macromolecule or, as a control, wild type human IgGl. Following washing with phosphate buffered saline (PBS) containing 0.05% v / v Tween 20 (PBST) and PBS, wells were incubated in 1% (w / v) skimmed milk in PBS. Wells were then washed with PBST and PBS. and 5 pg / ml complement Clq conjugated to HRP in 1 % (w / v) skimmed milk in PBS was added. Following washing with PBST and MilliQ water, TMB substrate (e.g. BioFX® TMB One Component HRP Mi crowell Substrate) was added to detect bound HRP. The results presented in FIGURES 9A, 9B and 9C show that exemplary macromolecules that target ADAMTS13-specific antibodies with mutations to reduce binding to FcyRs (TTP 027 + TTP J 68, TTP 061 + TTP 160, TTP 027 + TTP 078; see Table 2 for corresponding SEQ ID NOs) have levels of binding that are close to background signal, indicating effective removal of Fc / R binding. The results presented in FIGURE 9D show that exemplary FcyRIIb-targeting macromolecules that target AD AMTS 13-specific antibodies with mutations to increase binding to FcyRIIb (TTP 108 + TTP 109, TTP 112 + TTP 113 and TTP 247 + TTP 248; see Table 2 for corresponding SEQ ID NOs) bind to FcyRIIb (CD32b), whereas a macromolecule with mutations to ablate FcyR(IIb) interactions shows background levels of binding in these assays (TTP_027 + TTP_168; see Table 2 for corresponding sequence ID NOs).

[0210] In addition, exemplary molecules that target ADAMTS 13 -specific antibodies with mutations to reduce binding to complement Clq (TTP 027 + TTP 078, TTP 061 + TTP 160, TTP_027 + TTP_168; see Table 2 for corresponding SEQ ID NOs) show levels of binding to this protein at background levels (FIGURES 9E and 9F).

[0211] Example 4: Binding of ADAMTS 13-specific autoantibodies to exemplary macromolecules that target ADAMTS 13-specific antibodies

[0212] To analyze the binding of macromolecules that target ADAMTS 13 -specific antibodies to autoantibodies in plasma samples of iTTP patients, wells of ELISA plates were coated with purified macromolecule, washed with PBS containing 0.05% v / v Tween 20 (PBST), followed by PBS only, and then incubated with blocking buffer (Chonblock). As controls, an Fc fusion comprising an irrelevant antigen component (TTP Controll) or PBS were used to coat wells, followed by washing as above and treatment with blocking buffer. Following washing with PBST and PBS, 1 :200 dilutions of plasma samples from iTTP patients were added to each well. As controls, serum from healthy controls (HC serum) was used. Following incubation and washing with PBST followed by PBS, wells w ere incubated with anti -human F(ab’)2-specific antibody conj ugated to horse-radish peroxidase (HRP). The wells were then washed with PBST followed by PBS, and TMB substrate (e.g. BioFX® TMB One Component HRP Microwell Substrate) was added to detect bound HRP conjugate.

[0213] The ELISA analyses demonstrate specific binding of exemplary macromolecules that target ADAMTS 13-specific antibodies and comprise different ADAMTS 13 domains (D, T, C and S or T. C and S): TTP 027 + TTP 078, TTP 061 + TTP 160, TTP 027 + TTP 168 (see Table 2 for corresponding SEQ ID NOs) to autoantibodies in plasma samples from iTTP patients (patients numbered 004-031; FIGURES 10A, 10B and 10C). The analyses also demonstrate that macromolecules comprising D, T, C and S or T, C and S domains of ADAMTS13 have similar binding behavior with ADAMTS 13 -specific antibodies.

[0214] Example 5; Ability of exemplary macromolecules that target ADAMTS13-specific antibodies to deplete ADAMTS13-specific antibodies

[0215] To analyze the depletion of ADAMTS13-specific antibodies from patient plasma samples by macromolecules that target ADAMTS 13-specific antibodies, wells of ELIS A plates were coated with purified macromolecules (ADAMTS 13-specific), a control macromolecule comprising an irrelevant antigen or BSA. washed with phosphate buffered saline (PBS) containing 0.05% v / v Tween 20 (PBST), followed by PBS only, and then incubated with blocking solution (3% w / v BSA in PBS). Dilutions (200-300 fold) of plasma samples in PBS were then added to wells, incubated (‘panned’) for one hour at room temperature and then transferred to a second well. This serial incubation was repeated for each sample for a total of six wells. Following the incubations, the presence of ADAMTS 13-specific antibodies in the samples that bind to various macromolecules comprising different domains of ADAMTS 13, or to recombinant full length ADAMTS 13 (rADAMTS13), were analyzed using the same protocol as in Example 4.

[0216] The results presented in FIGURES 11A, 1 IB, 11C, 1 ID. 1 IE, 1 IF, 11G, 11H. 1 II, 11J, 1 IK and 11 L demonstrate that exemplary macromolecules (TTP 061 + TTP l 60, TTP 027 + TTP_168, TTP_027 + TTP_078; see Table 2 for corresponding SEQ ID NOs) that target ADAMTS 13-specific antibodies can deplete antibodies specific for full length, recombinant ADAMTS 13 (rADAMTS13) in patient plasma samples. To demonstrate the specificity of depletion, the reduction of ADAMTS 13-specific antibodies is also greater following incubation of plasma samples with wells coated with macromolecules that target ADAMTS 13 -specific antibodies compared with wells coated with a control macromolecule (comprising an irrelevant antigen; TTP_Control2, that as shown on the left side of each panel, is effective in depleting antibodies specific for this irrelevant antigen) or bovine serum albumin (BSA). By comparing the behavior of an exemplary macromolecule that comprises D, T, C and S domains (TTP 027 + TTP 078) with ones that comprise T, C and S domains (TTP 061 + TTP 160 and TTP 027 + TTP_168), the results demonstrate that the absence of the D domain of ADAMTS 13 does not affect the ability of the macromolecule to remove ADAMTS 13-specific antibodies. Example 6: Ability of exemplary macromolecules that target ADAMTS13-specific antibodies to deplete ADAMTS13-specific antibodies in mice

[0217] To determine the ability of macromolecules that target ADAMTS13-specific antibodies to specifically deplete ADAMTS13-specific antibodies in vivo, C57BL / 6J mice were injected with 25 pg ADAMTS13-specific antibody (n = 2 mice / group). The recombinant human IgGl / kappa antibody was generated using the VH and VL domain sequences of the 1-420 antibody (TTP Tracerl, specific for CS domains; WO 2016 / 164468 A2, Human monoclonal antibodies to ADAMTS13 and uses thereof, inventors: Siegel, D.L., Kacir, S., Ostertag, E., Zheng, X.L.). Three days later, mice were injected with a 4-fold molar excess of an exemplary macromolecule that targets ADAMTS 13 -specific antibodies or a control macromolecule comprising an irrelevant antigen (TTP Controll) via intravenous injection. Blood samples were taken from mice prior to and following antibody and macromolecule injections (see plots for sampling times) and levels of ADAMTS 13-specific antibodies in serum were determined using ELISA.

[0218] The data shown in FIGURE 12 demonstrate that, compared with the effect of the control macromolecule (TTP Controll), an exemplary macromolecule that targets ADAMTS13- specific antibodies (TTP_027 + TTP_168; see Table 2 for corresponding SEQ ID NOs) induces a rapid and substantial decrease in ADAMTS 13 -specific antibody in the circulation of mice.

[0219] Example 7; Binding of ADAMTS 13-specific autoantibodies to exemplary FcyRIIb-tar eting macromolecules that target ADAMTS13-specific antibodies

[0220] To analyze the binding of FcvRIIb-targeting macromolecules that target ADAMTS13- specific antibodies to autoantibodies in plasma samples of iTTP patients, wells of ELISA plates were coated with purified macromolecule, washed with PBS containing 0.05% v / v Tween 20 (PBST), followed by PBS only, and then incubated with blocking solution (Chonblock). As controls, an Fc fusion comprising an irrelevant antigen component (TTP_Control3) or PBS (labeled PBS) were used to coat wells, followed by washing as above and treatment with blocking buffer. Following washing with PBST and PBS, 1 :200 dilutions of plasma samples from iTTP patients were added to each well. As controls, serum from healthy controls (HC serum) was used. Following incubation and washing with PBST followed by PBS, wells w ere incubated with anti-human F(ab’)2-specific antibody conjugated to horse-radish peroxidase (HRP). The wells were then washed with PBST followed by PBS, and TMB substrate (e.g. BioFX® TMB One Component HRP Microwell Substrate) was added to detect bound HRP conjugate.

[0221] The ELISA analyses shown in FIGURE 13 demonstrate specific binding of antibodies in plasma samples of seropositive iTTP patients to exemplary FcyRIIb-targeting macromolecules that target ADAMTS13-specific antibodies and comprise D, T, C and S (TTP 108 + TTP 109, TTP 112 + TTP 113; see Table 2 for corresponding SEQ ID NOs) or T, C and S (TTP_247 + TTP_248; see Table 2 for corresponding SEQ ID NOs) domains of ADAMTS13.

[0222] Example 8; Ability of exemplary FcyRIIb-targeting macromolecules that target ADAMTS13-specific antibodies to lead to accumulation of ADAMTS13-specific antibodies in FcyRIIb-expressing cells

[0223] To analyze the ability of FcyRIIb-targeting macromolecules that target ADAMTS 13- specific antibodies to result in accumulation of ADAMTS13-specific antibodies in FcyRIIb- expressing cells, the following assay was carried out: CHO-K1 cells expressing FcyRIIb (Promega) were seeded at a density of 0.25 x 106cells per well in 96 well plates and incubated for 16-18 hours in a 37°C incubator with 5% CO2. Cells were incubated with FcyRIIb-targeting macromolecule (TTP 108 + TTP 109, TTP 112 + TTP 113 and TTP 247 + TTP 248; see Table 2 for corresponding SEQ ID NOs) premixed at a fourfold molar excess (200 nM: 50 nM) with Alexa Fluor 647-conjugated AD AMTS 13-specific antibody (TTP Tracerl ; AD AMTS 13- specific; expressed and purified as chimeric mouse VH / VL domains with human IgGl / kappa) for 60 minutes in a 37°C incubator with 5% CO?. As controls, Alexa Fluor 647-conjugated ADAMTS13-specific antibody (TTP Tracerl) was mixed with vehicle (PBS) or with an FcyRIIb-targeting macromolecule comprising an irrelevant antigen (TTP_Control4). Following the incubation, cells were washed, detached from the plate wells by trypsinization. washed and analyzed by flow cy tometry .

[0224] The results presented in FIGURE 14 demonstrate that incubation of exemplary FcyRIIb-targeting macromolecules that target ADAMTS 13 -specific antibodies (TTP_108 + TTP 109, TTP l 12 + TTP l 13 and TTP 247 + TTP 248; see Table 2 for corresponding SEQ ID NOs) with an ADAMTS 13-specific antibody (TTP Tracerl) leads to the accumulation of the antibody in FcyRIlb-expressing cells (labeled TTP 108 + TTP 109; TTP l 12 + TTP l 13; TTP_247 + TTP_248). The specificity of this accumulation is demonstrated by incubating the cells with ADAMTS13-specific antibody alone (TTP Tracerl), or TTP Tracerl mixed with an FcyRIIb-targeting macromolecule comprising an irrelevant antigen (i.e. not ADAMTS13 or AD AMTS 13 domains; TTP_Control4) (FIGURE 14).

[0225] Example 9; Binding of exemplary ASGPR-targeting macromolecules that target ADAMTS13-specific antibodies to ASGPR and ADAMTS13-specific antibodies

[0226] To assess the binding of exemplary ASGPR-targeting macromolecules that target ADAMTS13-specific antibodies to ASGPR, wells of ELISA plates were coated with recombinant ASGPR (5 pg / ml), washed with PBS containing 0.05% v / v Tween 20 (PBST), followed by PBS only, and then incubated with blocking solution (3% w / v bovine serum albumin, BSA, in PBS). Following washing with PBST and PBS, ASGPR-targeting macromolecules (TTP 214 + TTP 216 + TTP 217 and TTP 214 + TTP 216 + TTP 218; see Table 2 for corresponding SEQ ID NOs) or control macromolecule (TTP_027 + TTP_168, that is not expected to bind to ASGPR; see Table 2 for corresponding SEQ ID NOs) were added at a concentration of 33 nM. Following incubation and washing with PBST followed by PBS, wells were incubated with anti -human Fc-specific antibody conjugated to horse-radish peroxidase (HRP). The wells were then washed with PBST followed by PBS, and TMB substrate (e.g. BioFX® TMB One Component HRP Microwell Substrate) added to detect bound HRP conjugate.

[0227] The results presented in FIGURE 15 A demonstrate that exemplar}’ ASGPR-targeting macromolecules that target ADAMTS13-specific antibodies (TTP_214 + TTP_216 + TTP_217 and TTP_214 + TTP_216 + TTP_218; see Table 2 for corresponding SEQ ID NOs) bind specifically to recombinant ASGPR.

[0228] Surface plasmon resonance experiments to analyze the interactions of exemplary ASGPR-targeting macromolecules that target ADAMTS13-specific antibodies with TTPTracerl (ADAMTS 13 -specific; expressed and purified as chimeric mouse VH / VL domains with human IgGl / kappa) were carried out using a BIAcore T200 (GE Healthcare). Binding of macromolecules was analyzed by injecting 500 nM macromolecule over immobilized TTP Tracerl (coupled at 1226 RU on a CM5 sensor chip) in PBS (pH 7.4) plus 0.05% v / v Tween-20 at a flow' rate of 10 pl / minute. Flow cells were regenerated following each injection and dissociation phase using 10 mM NaOH. The sensorgram shown in FIGURE 15B indicates that an exemplary ASGPR-targeting macromolecule that targets ADAMTS 13 -specific antibodies (TTP 214 + TTP 216 + TTP 217 see Table 2 for corresponding SEQ ID NOs) binds to ADAMTS 13 -specific antibody.

[0229] Example 10: Ability of exemplary ASGPR-targeting macromolecules that target ADAMTS 13-specific antibodies to lead to accumulation of ADAMTS 13-specific antibodies in ASGPR-expressing cells

[0230] To analyze the ability of ASGPR-targeting macromolecules that target ADAMTS 13- specific antibodies to result in accumulation of ADAMTS 13 -specific antibodies in ASGPR- expressing cells, the following assay was carried out: Hep G2 cells (ATCC, HB-8065) were seeded at a density of 0.25 x 106cells per well in 96 well plates and incubated for 16-18 hours in a 37°C incubator with 5% CO2. Cells were incubated with ASGPR-targeting macromolecule (TTP 214 + TTP 216 + TTP 217 and TTP 214 + TTP 216 + TTP 218; see Table 2 for corresponding SEQ ID NOs) premixed at a fourfold molar excess (200 nM: 50 nM) with Alexa Fluor 647-conjugated ADAMTS 13-specific antibody (TTP_Tracerl) for 60 minutes in a 37°C incubator with 5% CO2. As a control, Alexa Fluor 647-conjugated ADAMTS 13 -specific antibody (TTP Tracerl) was mixed with vehicle (PBS). Following the incubation, cells were washed, detached from the plate wells by trypsinization. washed and analyzed by flow cytometry.

[0231] The results presented in FIGURE 16 demonstrate that incubation of exemplary ASGPR-targeting macromolecules that target ADAMTS 13-specific antibodies (TTP_214 + TTP 216 + TTP 217 and TTP 214 + TTP 216 + TTP 218; see Table 2 for corresponding SEQ ID NOs) with an ADAMTS 13-specific antibody (TTP Tracerl) leads to the accumulation of the antibody in ASGPR-expressing cells (labeled TTP 214 + TTP 216 + TTP 217; TTP 214 + TTP 216 + TTP 218). The specificity of this accumulation is demonstrated by incubating the cells with ADAMTS13-specific antibody alone (TTP Tracerl) (FIGURE 16).

[0232] Example 11: Generation of macromolecules that target ADAMTS13-specific antibodies and comprise targeting components that bind to the internalizing receptor ASGPR

[0233] To generate exemplary macromolecules that target ADAMTS 13-specific antibodies by binding through their targeting component to ASGPR, the following approaches can be used: the genes encoding one or more of the M, D, T, C. S, CUB1 or CUB2 domains, or all domains of ADAMTS 13, can be linked to the N- or C-termini of human serum albumin (HSA) or the Dili domain of HSA via linkers such as G4S or (G4S)s (thereby encoding SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ ID NO: 42, SEQ ID NO: 45, or SEQ ID NO: 46). For additional embodiments, the genes encoding one or more of the M, D, T, C or S domains can be linked to the N- (or C-) termini of HSA or the Dill domain of HSA, and the genes encoding one or more of the CUBland CUB2 domains linked to the C- (or N-) termini of HSA or the Dill domain of HSA via linkers such as G4S (SEQ ID NO: 43, or SEQ ID NO: 44). The corresponding proteins can be expressed in transfected CHO cells, or other suitable expression host, and purified. The design of these constructs is similar to that shown in FIGURES 2H and 21. Following size exclusion purification, recombinant fusion proteins can be conjugated to targeting molecules that bind to ASGPR (monovalent, divalent or trivalent; FIGURE 17) via Cys34 on HSA, or via Lys residues in the HSA-fusion constructs, to generate conjugates with multiple (e.g. 1-6) ligands attached. As examples, a phenyl maleimide group or pentafluorophenyl (PFP; -C(O)O-pentafluorophenyl) group attached via a linker to the (branched) ASGPR-targeting molecule can be used to conjugate to Cys or Lys residues, respectively. The chemical synthesis of the ASGPR-targeting molecules and conjugation chemistry can be carried out using methods known to those with skill in the art and, for example, are described in the following: International Publication No. WO 2023 / 288033 Al. ASGPR cell surface receptor binding compounds and conjugates, inventors: Bush, B.B., Ernst, J.T., Packard, G.K., Lewis, J.G., Turtle, E.D.; International Publication No. WO 2025 / 035040 AL Lysosomal targeting bifunctional molecules for degradation of muscle-specific kinase autoantibodies, inventors: Chen. T., Iwig, J., Lewis, J.G.. Lieser, R., Staben. S., Totten, S.M., Turtle, E D.

[0234] Additional exemplary embodiments include those in which HSA is replaced by an immunoglobulin Fc fragment (e.g. SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51. or SEQ ID NO: 52). Mutations (L234S / L235T / G236R, L234A / L235A / P329G or L234A / L235A / D265S; EU numbering) to ablate binding to FcyRs can be inserted into the Fc fragment genes, that can also have knobs-into-holes mutations (e.g. T366W) to drive heterodimer formation. For expression as heterodimers, Fc fragment genes with FcyR-ablating mutations (L234S / L235T / G236R, L234A / L235A / P329G or

[0235] L234A / L235A / D265S; EU numbering) (thereby encoding, for example, SEQ ID NO: 20), in some cases with additional antigen components comprising ADAMTS13 domains attached (thereby encoding, for example, SEQ ID NO: 53), can be generated with complementary knobs-into-holes mutations (e.g. T366S / L368A / Y407V; EU numbering). The design of these constructs is similar to that shown in FIGURES 2A, 2B, 2C, 2D, 2E, 2F and 2G, and can also include the insertions of mutations (e.g. M252Y / S254T / T256E; EU numbering) to increase binding to FcRn.

[0236] Additional embodiments for macromolecules comprising targeting components that bind to ASGPR can be made by the generation of expression constructs for one or more of the M, D, T, C, S, T2, T3, T4, T5, T6, T7, T8, CUB1 or CUB2 domains (e.g. SEQ ID NO: 54, SEQ ID NO:55, SEQ ID NO: 56, SEQ ID NO: 57, SEQ ID NO: 58, SEQ ID NO: 59, or SEQ ID NO: 60). For expression of two or more ADAMTS13 domains, domains that are not contiguous in the natural ADAMTS13 sequence can be linked by, for example, GS or G4S (SEQ ID NO: 85) linkers. Recombinant ADAMTS13 proteins can be expressed and purified from transfected CHO cells or other suitable expression host. Alternatively, the domains can be expressed as separate constructs comprising one or more of the following domains: M, D, T, C, S, T2, T3, T4, T5, T6, T7, T8, CUB1 or CUB2. Following size exclusion purification, the ADAMTS13 proteins can be conjugated via Cys or Lys residues using methods known to those with skill the art to targeting molecules that bind to ASGPR (e.g. FIGURE 18). Additional embodiments can include one or more ADAMTS13 domains expressed as fusion proteins with immunoglobulin Fc fragments, as described above (SEQ ID NO: 47, SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 52, or SEQ ID NO: 53), follow ed by conjugation to ASGPR-targeting molecules. Exemplary ASGPR-targeting molecules are described in the following: US patent 12,128,105 B2, Molecular degraders of extracellular proteins, inventors: Caianiello. D.. Deramon, E.. Spiegel, D.; International Publication No. WO 2022 / 192478 Al , Bifunctional degraders of galactose-deficient immunoglobulins, inventors, Dubowchik, G.M., Spiegel, D., Caldwell, R.M.; International Publication No. WO 2025 / 035052 Al, Molecular degraders for the treatment of IgA nephropathy, inventors: Kazmierski, W., Pracitto, R., Dubowchik. G.M., Marcin. L.R.. Bunin, A., Rossi, A.M., Iben, L.G., McGrath, K., Lee, S., Todd, M.; International Publication No. WO 2025 / 081173 A2, Bispecific molecular degraders of pathogenic proteins, inventors: Bunin, A., Car, B., Dow, M., Gardin, T., Lipson, S., Marcin, L.R., Mellott, D., Murray, S., Pirman, D., Velaparthi. SEQUENCE LISTING

[0237] Table 1: Sequence identifiers of targeting and antigen components that can be combined with each other to generate macromolecules that target AD AMTS 13-specific antibodies Table 2; Sequence identifiers and properties of exemplary macromolecules that target AD AMTS 13-specific antibodies

[0238] Table 3: Sequence identifiers and receptor targets of exemplary macromolecules that target ADAMTS 13 -specific antibodies

[0239]

[0240] The above disclosed subject mater is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present disclosure. Thus, to the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.

Claims

CLAIMS1. A macromolecule that targets ADAMTS 13 -specific antibodies, comprising: a targeting component configured to specifically bind to a cell surface receptor or other cell surface molecule; and an antigen component fused directly or indirectly to the targeting component, wherein the antigen component comprises at least part of a spacer (S) domain of ADAMTS 13 and is configured to specifically bind to an ADAMTS 13-specific antibody.

2. The macromolecule of claim 1, wherein the antigen component further comprises at least part of a Cys-rich (C) domain of ADAMTS 13.

3. The macromolecule of claim 2, wherein the antigen component further comprises at least part of a first thrombospondin type 1 (TSP1) repeat (T) domain of ADAMTS 13.

4. The macromolecule of claim 3, wherein the antigen component comprises substantially the entirety of the T, C and S domains of ADAMTS 13.

5. The macromolecule of claim 1, wherein the antigen component further comprises at least part of a disintegrin-like (D) domain of ADAMTS 13.

6. The macromolecule of claim 5, wherein the antigen component further comprises at least part of a metalloprotease (M) domain of ADAMTS 13.

7. The macromolecule of claim 1, wherein the antigen component further comprises at least part of a CUB1 domain of ADAMTS13.

8. The macromolecule of claim 7, wherein the antigen component further comprises at least part of a CUB2 domain of ADAMTS 13.

9. The macromolecule of claim 1, wherein the targeting component comprises an immunoglobulin Fc fragment.

10. The macromolecule of claim 9, wherein the immunoglobulin Fc fragment is modified to have substantially reduced binding affinity for Fc gamma receptors compared to an unmodified immunoglobulin Fc fragment.

11. The macromolecule of claim 10, wherein the immunoglobulin Fc fragment comprises mutations L234S / L235T / G236R according to EU numbering.

12. The macromolecule of claim 9, wherein the immunoglobulin Fc fragment is modified to have substantially reduced binding affinity for complement Clq compared to an unmodified immunoglobulin Fc fragment.

13. The macromolecule of claim 9, wherein the immunoglobulin Fc fragment is modified to have a higher binding affinity for FcRn at near-neutral pH than an unmodified immunoglobulin Fc fragment.

14. The macromolecule of claim 13. wherein the immunoglobulin Fc fragment comprises mutations M252Y / S254T / T256E / H433K / N434F according to EU numbering.

15. The macromolecule of claim 9, wherein the immunoglobulin Fc fragment is modified to have increased binding affinity for FcyRIIb compared to an unmodified immunoglobulin Fc fragment.

16. The macromolecule of claim 15. wherein the immunoglobulin Fc fragment comprises mutations selected from the group consisting of P238D, G237D / P271G / A330R, G237D / H268D / P271G / A330R, G236N / H268D / A330K, and S267E / L328F according to EU numbering.

17. The macromolecule of claim 9, wherein the targeting component comprises a heterodimer of two immunoglobulin Fc fragments.

18. The macromolecule of claim 17, wherein one immunoglobulin Fc fragment of the heterodimer is fused to the antigen component and the other immunoglobulin Fc fragment is not fused to the antigen component.

19. The macromolecule of claim 17, wherein the heterodimer comprises knobs-into-holes mutations.

20. The macromolecule of claim 19, wherein the knobs-into-holes mutations comprise T366W in one Fc fragment and T366S / L368A / Y407V in the other Fc fragment according to EU numbering.

21. The macromolecule of claim 9, wherein the antigen component is fused to an N-terminus of the immunoglobulin Fc fragment.

22. The macromolecule of claim 9, wherein the antigen component is fused to a C-terminus of the immunoglobulin Fc fragment.

23. The macromolecule of claim 1, wherein the targeting component comprises albumin or an albumin fragment.

24. The macromolecule of claim 23, wherein the albumin or albumin fragment is configured to specifically bind to FcRn.

25. The macromolecule of claim 1, wherein the targeting component comprises one or more antibody variable regions configured to specifically bind to the cell surface receptor or cell surface molecule.

26. The macromolecule of claim 25, wherein the one or more antibody variable regions comprise at least one nanobody.

27. The macromolecule of claim 1, wherein the cell surface receptor or cell surface molecule is FcRn.

28. The macromolecule of claim 27, wherein the targeting component can bind to FcRn with a dissociation constant of less than 10 pM at near-neutral pH.

29. The macromolecule of claim 1, wherein the cell surface receptor or cell surface molecule is a transferrin receptor.

30. The macromolecule of claim 1, wherein the cell surface receptor or cell surface molecule is an asialoglycoprotein receptor (ASGPR).

31. The macromolecule of claim 30, wherein the targeting component comprises an antibody or antibody fragment that specifically binds to ASGPR.

32. The macromolecule of claim 1, wherein the cell surface receptor or cell surface molecule is FcyRIIb.

33. The macromolecule of claim 1, wherein the cell surface receptor or cell surface molecule is CD163.

34. The macromolecule of claim 1, wherein the cell surface receptor or cell surface molecule is a mannose 6-phosphate receptor.

35. The macromolecule of claim 1, wherein the cell surface receptor or cell surface molecule is phosphatidylserine.

36. The macromolecule of claim 35, wherein the targeting component comprises a C2A domain of synaptotagmin 1.

37. The macromolecule of claim 1, wherein the targeting component comprises a carbohydrate or carbohydrate derivative configured to specifically bind to the cell surface receptor or cell surface molecule.

38. The macromolecule of claim 1. wherein the targeting component comprises a small molecule configured to specifically bind to the cell surface receptor or cell surface molecule.

39. The macromolecule of claim 1, wherein the antigen component is fused to the targeting component via a linker.

40. The macromolecule of claim 39, wherein the linker comprises a glycine-serine linker, optionally a glycine-glycine-glycine-glycine-serine (GGGGS: SEQ ID NO: 85) linker peptide.

41. The macromolecule of claim 1. further comprising a second antigen component that is different from the first antigen component.

42. The macromolecule of claim 41. wherein the second antigen component comprises one or more domains of ADAMTS13 different from those in the first antigen component.

43. The macromolecule of claim 1, wherein the macromolecule comprises an amino acid sequence having at least 90% sequence identity to a sequence selected from the group consisting of SEQ ID NO: 1 through SEQ ID NO: 83.

44. The macromolecule of claim 1, wherein the macromolecule comprises a heterodimer of proteins having amino acid sequences of SEQ ID NO: 2 and SEQ ID NO: 4.

45. The macromolecule of claim 1, wherein the macromolecule comprises a heterodimer of proteins having amino acid sequences of SEQ ID NO: 2 and SEQ ID NO: 18.

46. The macromolecule of claim 1, wherein the macromolecule has substantially reduced binding to von Willebrand Factor compared to full-length ADAMTS13.

47. The macromolecule of claim 4, wherein the macromolecule has substantially reduced binding to von Willebrand Factor compared to a macromolecule comprising D, T, C and S domains of ADAMTS 13.

48. A method of depleting ADAMTS 13-specific antibodies from a patient, comprising administering to the patient the macromolecule of claim 1 in an amount sufficient to remove at least 50% of the ADAMTS 13 -specific antibodies from circulation in the patient.

49. The method of claim 48, wherein the macromolecule is administered in an amount sufficient to remove at least 80% of the ADAMTS 13-specific antibodies from circulation in the patient.

50. The method of claim 48, wherein the ADAMTS 13 -specific antibodies are specific for theT, C or S domain of ADAMTS 13.

51. The method of claim 49, wherein the ADAMTS 13-specific antibodies are specific for the T, C or S domain of ADAMTS 13.

52. The method of claim 48, wherein the patient has immune-mediated thrombotic thrombocytopenic purpura (iTTP).

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