Methods for treating complement-mediated diseases

Abstract

Provided herein is a method of treating cold agglutinin disease (CAD) or chronic inflammatory demyelinating polyneuropathy (CIDP) in a subject in need thereof. The method comprises administering to the subject a humanized antibody that specifically binds to complement component C1s (anti-C1s antibody). The method of treating CAD comprises administering the anti-C1s antibody to the subject at a fixed dose. The method of treating CIDP comprises administering to the subject one or more fixed maintenance doses following a loading dose of the anti-C1s antibody based on body weight. The method comprises administering an effective amount of the anti-C1s antibody to achieve a minimum level of CP inhibition for a therapeutic effect.

Description

Technical Field

[0001] Related Applications This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63 / 355,296, filed on June 24, 2022; U.S. Provisional Patent Application No. 63 / 370,484, filed on August 4, 2022; U.S. Provisional Patent Application No. 63 / 375,041, filed on September 8, 2022; and U.S. Provisional Patent Application No. 63 / 379,626, filed on October 14, 2022, the entire contents of each of which are incorporated herein by reference.

[0002] Reference to Sequence Listing The electronic sequence listing (filename: B155370018WO00-SEQ-JRV; size: 21,392 bytes; and creation date: June 19, 2023) is incorporated herein by reference in its entirety.

Background Art

[0003] The complement system is a well-known effector mechanism of the immune response, providing defense against pathogens and other harmful substances as well as recovery from injury. The classical complement pathway is induced by the activation of the first component of complement, called the C1 complex, which includes the C1q, C1r, and C1s proteins. When C1 binds to an immune complex, the C1s component, a diisopropylfluorophosphate (DFP)-sensitive serine protease, cleaves the complement components C4 and C2 to initiate the activation of the classical complement pathway. The classical complement pathway appears to play a role in many diseases and disorders, and there is a need for safe and effective treatments that target this pathway.

Summary of the Invention

Means for Solving the Problems

[0004] The present disclosure provides a method of treating classical complement-mediated disorders such as cold agglutinin disease (CAD) and chronic inflammatory demyelinating polyneuropathy (CIDP) using a humanized antibody that specifically binds to complement C1s protein (i.e., a humanized anti-complement C1s antibody, also referred to herein as a "humanized anti-C1s antibody", a "humanized C1s antibody", or a "subject antibody").

[0005] For classical complement-mediated disorders such as CAD and CIDP, treatment options are limited. The subject antibody, a humanized monoclonal antibody directed against activated C1s, can provide clinical benefit to patients with classical complement system diseases by specifically targeting the activated classical pathway. The studies described herein evaluate the safety, tolerability, and pharmacokinetic and pharmacodynamic profiles of the subject antibody in healthy participants as well as in CAD and CIDP patients. It is demonstrated herein that the subject antibody was generally well tolerated. The subject antibody exhibited acceptable bioavailability and a long elimination half-life with linear kinetics following SC administration. The subject antibody further inhibited the classical complement pathway (CP) and 50% hemolytic complement activity (CH50) in a dose-dependent manner to levels consistent with complement deficiency states. Preliminary results in CIDP patients further show that treatment with the subject antibody can improve functional impairment as measured by the INCAT score in patients with CIDP resistant to other CIDP treatments and in patients with CIDP treated with standard therapy. The results support further evaluation of the subject antibody in diseases characterized by complement classical pathway dysfunction or uncontrolled activation such as CAD and CIDP.

[0006] In one aspect, the present disclosure provides a method for treating cold agglutinin disease in a subject in need thereof, the method comprising administering to the subject an approximately 3.5 g of a humanized antibody that specifically binds to complement component C1s, wherein the antibody comprises a light chain (LC) complementarity determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a heavy chain (HC) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6.

[0007] In some embodiments, the antibody is administered approximately every 10, 12, 14, or 16 weeks. In some embodiments, the antibody is administered approximately every 12 weeks.

[0008] In some embodiments, an approximately 3.5 g of the antibody is administered approximately 4 weeks after the first administration.

[0009] In some embodiments, the antibody is administered intravenously or subcutaneously. In some embodiments, the antibody is administered intravenously.

[0010] In some embodiments, an approximately 3.5 g of the antibody is administered intravenously on day 1 and then approximately every 10, 12, 14, or 16 weeks, and an approximately 3.5 g of the antibody is administered intravenously on day 29 or approximately day 29. In some embodiments, 3.5 g of the antibody is administered intravenously on day 1 and then approximately every 10, 12, 14, or 16 weeks, and 3.5 g of the antibody is administered intravenously on day 29.

[0011] In some embodiments, an approximately 3.5 g of the antibody is administered intravenously on day 1 and then approximately every 12 weeks, and an approximately 3.5 g of the antibody is administered intravenously on day 29 or approximately day 29. In some embodiments, 3.5 g of the antibody is administered intravenously on day 1 and then approximately every 12 weeks, and 3.5 g of the antibody is administered intravenously on day 29.

[0012] In some embodiments, administration of the antibody increases the level of hemoglobin in the subject. In some embodiments, administration of the antibody decreases the level of bilirubin in the subject. In some embodiments, administration of the antibody inhibits the activity of the classical complement pathway by about 90% or more. In some embodiments, the activity of the classical complement pathway is determined by measuring the amount of the terminal complement complex C5b-9 upon administration of the antibody. In some embodiments, administration of the antibody decreases the 50% hemolytic complement activity (CH50) level to less than about 10 IU / mL. In some embodiments, after administration of the antibody, the subject has a plasma concentration of the antibody of at least about 100 μg / mL.

[0013] In one aspect, the present disclosure provides a method for treating chronic inflammatory demyelinating polyneuropathy (CIDP) in a subject in need thereof, the method comprising administering to the subject a loading dose of about 50 mg per kg of body weight of the subject of a humanized antibody that specifically binds to complement component C1s, and one or more maintenance doses of about 300 mg of the antibody, wherein the antibody comprises a light chain (LC) complementarity determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a heavy chain (HC) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6.

[0014] In one aspect, the present disclosure provides a method for treating chronic inflammatory demyelinating polyneuropathy (CIDP) in a subject in need thereof, the method comprising administering to the subject a loading dose of about 50 mg per kg of body weight of the subject of a humanized antibody that specifically binds to complement component C1s, and one or more maintenance doses of about 600 mg of the antibody, wherein the antibody comprises a light chain (LC) complementarity determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a heavy chain (HC) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6.

[0015] In one aspect, the present disclosure provides a method for treating chronic inflammatory demyelinating polyneuropathy (CIDP) in a subject in need thereof, the method comprising administering to the subject a loading dose of about 50 mg per kg of body weight of a humanized antibody that specifically binds to complement component C1s, and one or more maintenance doses of about 1200 mg of the antibody, wherein the antibody comprises a light chain (LC) complementarity-determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a heavy chain (HC) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6.

[0016] In one aspect, the present disclosure provides a method for treating chronic inflammatory demyelinating polyneuropathy (CIDP) in a subject in need thereof, the method comprising administering to the subject a loading dose of about 50 mg per kg of body weight of a humanized antibody that specifically binds to complement component C1s, and one or more maintenance doses of about 2400 mg of the antibody, wherein the antibody comprises a light chain (LC) complementarity-determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a heavy chain (HC) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6.

[0017] In one aspect, the present disclosure provides a method for treating chronic inflammatory demyelinating polyneuropathy (CIDP) in a subject in need thereof, the method comprising administering to the subject a loading dose of about 50 mg per kg of body weight of the subject of a humanized antibody that specifically binds to complement component C1s, and one or more maintenance doses of about 3600 mg of the antibody, wherein the antibody comprises a light chain (LC) complementarity determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a heavy chain (HC) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6.

[0018] In one aspect, the present disclosure provides a method for treating chronic inflammatory demyelinating polyneuropathy (CIDP) in a subject in need thereof, the method comprising administering to the subject a loading dose of about 50 mg per kg of body weight of the subject of a humanized antibody that specifically binds to complement component C1s, and one or more maintenance doses of about 7200 mg of the antibody, wherein the antibody comprises a light chain (LC) complementarity determining region (CDR) 1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, a heavy chain (HC) CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6.

[0019] In some embodiments, the one or more maintenance doses are administered about once a week, once every two weeks, once every four weeks, or once every twelve weeks.

[0020] In some embodiments, the antibody is administered intravenously or subcutaneously.

[0021] In some embodiments, the loading dose is administered intravenously. In some embodiments, the one or more maintenance doses are administered subcutaneously.

[0022] In some embodiments, a loading dose is administered intravenously on day 1, followed by maintenance doses administered subcutaneously approximately every week starting from day 8.

[0023] In some embodiments, a loading dose of approximately 50 mg of antibody per kg of the subject's body weight is administered intravenously on day 1, followed by maintenance doses of approximately 300 mg of antibody administered subcutaneously approximately every week starting from day 8. In some embodiments, a loading dose of 50 mg of antibody per kg of the subject's body weight is administered intravenously on day 1, followed by maintenance doses of 300 mg of antibody administered subcutaneously every week starting from day 8.

[0024] In some embodiments, a loading dose of approximately 50 mg of antibody per kg of the subject's body weight is administered intravenously on day 1, followed by maintenance doses of approximately 600 mg of antibody administered subcutaneously approximately every week starting from day 8. In some embodiments, a loading dose of 50 mg of antibody per kg of the subject's body weight is administered intravenously on day 1, followed by maintenance doses of 600 mg of antibody administered subcutaneously every week starting from day 8.

[0025] In some embodiments, a loading dose of approximately 50 mg of antibody per kg of the subject's body weight is administered intravenously on day 1, followed by maintenance doses of approximately 600 mg of antibody administered subcutaneously approximately every two weeks starting from day 8. In some embodiments, a loading dose of 50 mg of antibody per kg of the subject's body weight is administered intravenously on day 1, followed by maintenance doses of 600 mg of antibody administered subcutaneously every two weeks starting from day 8.

[0026] In some embodiments, a loading dose of approximately 50 mg of antibody per kg of the subject's body weight is administered intravenously on day 1, followed by maintenance doses of approximately 1200 mg of antibody administered subcutaneously approximately every two weeks starting from day 8. In some embodiments, a loading dose of 50 mg of antibody per kg of the subject's body weight is administered intravenously on day 1, followed by maintenance doses of 1200 mg of antibody administered subcutaneously every two weeks starting from day 8.

[0027] In some embodiments, a loading dose of the antibody of about 50 mg per kg of the subject's body weight is administered intravenously on day 1, followed by a maintenance dose of the antibody of about 1200 mg subcutaneously every about 4 weeks starting from day 29. In some embodiments, a loading dose of the antibody of 50 mg per kg of the subject's body weight is administered intravenously on day 1, followed by a maintenance dose of the antibody of 1200 mg subcutaneously every 4 weeks starting from day 29.

[0028] In some embodiments, a loading dose of the antibody of about 50 mg per kg of the subject's body weight is administered intravenously on day 1, followed by a maintenance dose of the antibody of about 2400 mg subcutaneously every about 4 weeks starting from day 29. In some embodiments, a loading dose of the antibody of 50 mg per kg of the subject's body weight is administered intravenously on day 1, followed by a maintenance dose of the antibody of 2400 mg subcutaneously every 4 weeks starting from day 29.

[0029] In some embodiments, a loading dose of the antibody of about 50 mg per kg of the subject's body weight is administered intravenously on day 1, followed by a maintenance dose of the antibody of about 3600 mg subcutaneously every about 12 weeks starting from day 29. In some embodiments, a loading dose of the antibody of 50 mg per kg of the subject's body weight is administered intravenously on day 1, followed by a maintenance dose of the antibody of 3600 mg subcutaneously every 12 weeks starting from day 29.

[0030] In some embodiments, a loading dose of the antibody of about 50 mg per kg of the subject's body weight is administered intravenously on day 1, followed by a maintenance dose of the antibody of about 7200 mg subcutaneously every about 12 weeks starting from day 29. In some embodiments, a loading dose of the antibody of 50 mg per kg of the subject's body weight is administered intravenously on day 1, followed by a maintenance dose of the antibody of 7200 mg subcutaneously every 12 weeks starting from day 29.

[0031] In some embodiments, a single intravenous loading dose of 50 mg / kg is administered on day 1, and the subcutaneous (SC) dose is administered using a prefilled syringe, or an autoinjector, or a large volume drug delivery system. In some embodiments, the SC dose administered is 300 mg qw, 600 mg qw, 600 mg q2w, 1200 mg q2w, 1200 mg q4w, 2400 mg q4w, 3600 mg q12w, or 7200 mg q12w. In some embodiments, the SC dose is administered using a prefilled syringe, or an autoinjector, or a large volume drug delivery system until the end of treatment.

[0032] In some embodiments, the subject is resistant to another CIDP treatment. In some embodiments, the subject has received another CIDP treatment within about one week of the loading dose, or is receiving another CIDP treatment concurrently. In some embodiments, the subject has not received another treatment for CIDP within about six months of the loading dose. In some embodiments, the other CIDP treatment is intravenous immunoglobulin (IVIG), subcutaneous immunoglobulin (SCIg), or corticosteroid.

[0033] In some embodiments, administration of the antibody results in a decrease of one point or more in the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score compared to the INCAT score before treatment with the antibody.

[0034] In some embodiments, after administration of the antibody, the subject has a plasma concentration of the antibody of at least about 1200 μg / mL.

[0035] In some embodiments, the antibody is contained in a syringe or vial.

[0036] In some embodiments, the antibody is administered using a syringe, a prefilled syringe, or a large volume drug delivery system.

[0037] In some embodiments, the antibody is administered using an autoinjector.

[0038] In some embodiments, the antibody is administered using a large volume device for subcutaneous injection.

[0039] In some embodiments, the antibody comprises a light chain variable region (VL) comprising the amino acid sequence of SEQ ID NO: 7 and a heavy chain variable region (VH) comprising the amino acid sequence of SEQ ID NO: 8.

[0040] In some embodiments, the antibody is a Fab fragment, F(ab’)2 fragment, scFv, or Fv.

[0041] In some embodiments, the antibody comprises a heavy chain constant region of isotype IgG4.

[0042] In some embodiments, the IgG4 constant region comprises proline, glutamate, leucine, and serine substitutions at amino acid residues 108, 115, 308, and 314, respectively, compared to the IgG4 constant region sequence of SEQ ID NO: 11.

[0043] In some embodiments, the IgG4 constant region comprises the sequence of SEQ ID NO: 13.

[0044] In some embodiments, the antibody comprises a light chain comprising the amino acid sequence of SEQ ID NO: 9 and a heavy chain comprising the amino acid sequence of SEQ ID NO: 10.

[0045] The international publication No. WO 2014 / 066744 pamphlet titled Anti-Complement C1s Antibodies and Uses Thereof filed on October 25, 2013, the international publication No. WO 2016 / 164358 pamphlet titled Humanized Anti-C1s Antibodies and Methods of Use Thereof filed on April 5, 2016, and the international publication No. WO 2018 / 071676 pamphlet titled Anti-C1s Antibodies and Methods of Use Thereof filed on October 12, 2017 are each incorporated herein by reference in their entirety.

Brief Description of Drawings

[0046]

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[0047] Humanized anti-C1s antibody The method of the present disclosure includes administering a humanized anti-C1s antibody. The humanized anti-C1s antibody of the present disclosure binds to and inhibits the activated form of C1s within the classical pathway (CP). The complement system is a component of the innate immune system that mediates humoral immunity. The mechanism of the antibody is specific to the CP, and the lectin and alternative pathways remain functionally intact.

[0048] In some embodiments, the humanized anti-C1s antibody of the present disclosure inhibits the C1s-mediated cleavage of complement component C4, for example, by inhibiting the enzymatic activity of the serine protease domain of C1s. In some embodiments, the humanized anti-C1s antibody of the present disclosure inhibits the C1s-mediated cleavage of complement component C2. In some embodiments, the humanized anti-C1s antibody of the present disclosure inhibits the C1s-mediated cleavage of C4 and C2.

[0049] In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to a complement C1s protein having the amino acid sequence set forth in SEQ ID NO: 15. The amino acid sequence of SEQ ID NO: 15 provided below is for Homo sapiens complement C1s protein:

Chemical formula

[0050] In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to human complement C1s protein with a dissociation constant (KD) of 2.5 nM or less. In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to human complement C1s protein with a KD of 2 nM or less. In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to human complement C1s protein with a KD of 1 nM or less. In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to human complement C1s protein with a KD of 0.9 nM or less, 0.8 nM or less, 0.7 nM or less, 0.6 nM or less, 0.5 nM or less, 0.4 nM or less, 0.3 nM or less, 0.2 nM or less, or 0.1 nM or less. In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to human complement C1s protein with a KD of 0.3 nM or less. In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to human complement C1s protein with a KD of 0.2 nM or less. In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to human complement C1s protein with a KD of 0.1 nM or less. Methods for measuring the binding of the antibody to human complement C1s protein can be determined by those skilled in the art.

[0051] In some embodiments, the humanized anti-C1s antibody of the present disclosure binds to human complement C1s protein with a KD of 90 pM or less, 80 pM or less, 70 pM or less, 60 pM or less, 50 pM or less, 40 pM or less, 30 pM or less, 20 pM or less, 10 pM or less, 9 pM or less, 8 pM or less, 7 pM or less, 6 pM or less, 5 pM or less, 4 pM or less, 3 pM or less, 2 pM or less, or 1 pM or less.

[0052] In some embodiments, the humanized anti-C1s antibody of the present disclosure preferentially binds to active (or activated) human complement C1s protein and substantially does not bind to the inactive form of human complement C1s protein.

[0053] In some embodiments, the humanized anti-C1s antibody of the present disclosure is 10 -8 M or less, 5×10 -9 M or less, or 10 -9 M or less of the half maximal inhibitory concentration (IC 50 ) inhibits the classical complement pathway.

[0054] "Antibody" includes, but is not limited to, antibodies and immunoglobulins of any isotype, including humanized antibodies and chimeric antibodies. The antibody can be a single-chain antibody (scAb) or a single-domain antibody (dAb) (see, e.g., Holt et al. (2003) Trends Biotechnol. 21:484). The term "antibody" also includes fragments of antibodies (antibody fragments) that retain specific binding to an antigen. "Antibody" is a fusion protein of the variable regions of the heavy chain (V H ) and light chain (V L ) of an antibody linked by a short linker peptide, a single-chain variable fragment (scFv), and a diabody, which is a non-covalent dimer of an scFv fragment containing V H and V L linked by a small peptide linker (Zapata et al., Protein Eng. 8(10):1057-1062 (1995)). Other fusion proteins containing the antigen-binding portion of an antibody and a non-antibody protein are also included within the term "antibody".

[0055] "Antibody fragment" includes a portion of an intact antibody, e.g., an antigen-binding or variable region of an intact antibody. Examples of antibody fragments include antigen-binding fragments (Fab), Fab’, F(ab’)2, variable domain Fv fragments (Fv), Fd fragments, and antigen-binding fragments of chimeric antigen receptors.

[0056] Papain digestion of an antibody produces two identical antigen-binding fragments called "Fab" fragments, each having a single antigen-binding site, and the remaining "Fc" fragment, which reflects the ability to crystallize readily. Pepsin treatment yields an F(ab’)2 fragment that has two antigen-binding sites and can still cross-link antigens.

[0057] "Fv" is the smallest antibody fragment that contains the complete antigen recognition and antigen-binding site. This region contains a dimer in which one heavy-chain variable domain and one light-chain variable domain are tightly non-covalently bound. In this configuration, the three CDRs of each variable domain interact to define the antigen-binding site on the surface of the V H -V L dimer. The six CDRs collectively confer antigen-binding specificity to the antibody. However, a single variable domain (or half of the Fv containing only three CDRs specific for the antigen) also has the ability to recognize and bind the antigen, although with lower affinity than the entire binding site.

[0058] The "Fab" fragment also contains the constant domain of the light chain and the first constant domain (CH1) of the heavy chain. The Fab fragment differs from the Fab' fragment in that several residues are added to the carboxyl terminus of the heavy-chain CH1 domain, which contains at least one cysteine from the antibody hinge region. Fab'-SH is the name in this specification for Fab' in which the cysteine residue of the constant domain has a free thiol group. F(ab')2 antibody fragments were originally produced as pairs of Fab' fragments that have hinge cysteines between them. Other chemical conjugates of antibody fragments are also known.

[0059] The "scFv" antibody fragment contains the V H and V L of the antibody, and these regions are present in a single polypeptide chain. In some embodiments, the Fv polypeptide further contains a polypeptide linker between the VH and VL regions, whereby the scFv can form the desired structure for antigen binding. For a review of scFv, see Pluckthun in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenberg and Moore eds., Springer-Verlag, New York, pp. 269-315 (1994).

[0060] "Diabody" refers to a small antibody fragment that has two antigen-binding sites, and this fragment is composed of the same polypeptide chain (VH -V L )'s V L V linked to H It contains. By using a linker that is too short for the formation of pairs between two domains on the same chain, the domains are forced to form pairs with complementary domains on another chain, creating two antigen-binding sites. Diabodies are more fully described, for example, in Hollinger et al. Proc. Natl. Acad. Sci. USA 90:6444-6448 (1993).

[0061] The antibody can be monovalent or divalent. The antibody can be an Ig monomer, which is a "Y-shaped" molecule composed of four polypeptide chains: two heavy chains and two light chains linked by disulfide bonds.

[0062] The antibody can be detectably labeled, for example, with a radioisotope, an enzyme that produces a detectable product, and / or a fluorescent protein. The antibody can also be conjugated to other moieties, such as a member of a specific binding pair, for example, the biotin member of a biotin-avidin specific binding pair. The antibody can also be bound to a solid support, including but not limited to polystyrene plates and / or beads.

[0063] An "isolated" antibody is one that has been identified, separated, and / or recovered from the components of its natural environment (i.e., it is not naturally occurring). The contaminating components of its natural environment are substances that would interfere with the use of the antibody (e.g., for diagnostic or therapeutic use), and can include enzymes, hormones, and other proteinaceous or non-proteinaceous solutes. In some embodiments, the antibody is purified to greater than 90%, greater than 95%, greater than 98%, or greater than 99% of the mass of the antibody as determined by the Lowry method, for example, to an extent sufficient to obtain at least 15 residues of the N-terminal or internal amino acid sequence by use of a spinning cup sequencer, or to homogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing or non-reducing conditions using Coomassie blue or silver staining. Isolated antibodies include antibodies in situ within recombinant cells since at least one component of the antibody's natural environment is not present. In some embodiments, the isolated antibody is prepared by at least one purification step.

[0064] A "monoclonal antibody" is an antibody that is produced by a group of identical cells all of which are produced by repeated cell replication from a single cell. That is, the clone of cells produces only a single antibody species. Monoclonal antibodies can be produced using hybridoma production techniques, but other production methods known to those of skill in the art can also be used (e.g., antibodies from antibody phage display libraries).

[0065] "Complementary determining region (CDR)" refers to non - adjacent antigen - binding sites found within the variable regions of both the heavy and light chain polypeptides. CDRs are described in Lefranc et al. (2003) Developmental and Comparative Immunology 27:55; Kabat et al., J. Biol. Chem. 252:6609 - 6616 (1977); Kabat et al., U.S. Dept. of Health and Human Services, "Sequences of Proteins of Immunological interest" (1991); by Chothia et al., J. Mol. Biol. 196:901 - 917 (1987); and MacCallum et al., J. Mol. Biol. 262:732 - 745 (1996), and the definitions include amino acid residue overlaps or subsets when compared to each other. Nevertheless, the application of the Kabat, Lefranc, Chothia, or MacCallum definitions (also called numbering systems) for referring to the CDRs of an antibody or a grafted antibody or their variants is intended to be within the scope of the terms defined and used herein.

[0066] The terms "LC CDR1", "LC CDR2", and "LC CDR3" refer to the 1st, 2nd, and 3rd CDRs, respectively, in the light - chain variable region. As used herein, the terms "HC CDR1", "HC CDR2", and "HC CDR3" refer to the 1st, 2nd, and 3rd CDRs, respectively, in the heavy - chain variable region. As used herein, the terms "CDR1", "CDR2", and "CDR3" refer to the 1st, 2nd, and 3rd CDRs, respectively, in the variable region of either chain.

[0067] "Framework", when used with respect to the variable region of an antibody, includes all amino acid residues outside of the CDR regions within the variable region of the antibody. The variable region framework is generally a discontinuous amino acid sequence that includes only the amino acids outside of the CDRs. "Framework region" includes each domain of the framework separated by the CDRs.

[0068] A "humanized antibody" is an antibody that includes portions of antibodies of different origins, where at least one portion includes an amino acid sequence of human origin. For example, a humanized antibody can include a portion derived from a non-human origin antibody having the required specificity, such as a mouse antibody, that is chemically conjugated by conventional techniques (e.g., synthesis) or prepared as an adjacent polypeptide using genetic engineering techniques (e.g., expressing DNA encoding the protein portion of a chimeric antibody to produce adjacent polypeptide chains), and a portion derived from an antibody sequence of human origin (e.g., a chimeric immunoglobulin). Another example of a humanized antibody is an antibody containing at least one chain that includes CDRs derived from a non-human origin antibody and framework regions derived from a human origin light chain and / or heavy chain (e.g., a CDR grafted antibody with or without framework modifications). Chimeric or CDR grafted single chain antibodies are also encompassed by the term humanized immunoglobulin. See, for example, Cabilly et al., U.S. Patent No. 4,816,567; Cabilly et al., European Patent No. 0,125,023B1; Boss et al., U.S. Patent No. 4,816,397; Boss et al., European Patent No. 0,120,694B1; Neuberger, M.S. et al., International Publication No. 86 / 01533 Pamphlet; Neuberger, M.S. et al., European Patent No. 0,194,276B1; Winter, U.S. Patent No. 5,225,539; Winter, European Patent No. 0,239,400B1; Padlan, E.A. et al., European Patent Application Publication No. 0,519,596A1. See also Ladner et al., U.S. Patent No. 4,946,778; Huston, U.S. Patent No. 5,476,786; and Bird, R.E. et al., Science, 242:423-426 (1988) for single chain antibodies.

[0069] In some embodiments, humanized antibodies are produced using synthetic and / or recombinant nucleic acids to prepare a gene (e.g., cDNA) encoding a desired humanized chain. For example, a nucleic acid (e.g., DNA) sequence encoding a humanized variable region can be constructed using PCR mutagenesis methods to alter a DNA sequence encoding a human or humanized chain, such as a DNA template from a previously humanized variable region (e.g., see Kamman, M., et al., Nucl. Acids Res., 17:5404 (1989); Sato, K., et al., Cancer Research, 53:851-856 (1993); Daugherty, B.L. et al., Nucleic Acids Res., 19(9):2471-2476 (1991); and Lewis, A.P. and J.S.C. Crowe, Gene, 101:297-302 (1991)). Variants can also be readily produced using these or other suitable methods. For example, cloned variable regions can be mutagenized and sequences encoding variants with desired specificities can be selected (e.g., from phage libraries; e.g., see Krebber et al., U.S. Patent No. 5,514,548; Hoogenboom et al., International Publication No. 93 / 06213 pamphlet, published on April 1, 1993).

[0070] In some embodiments, the humanized anti-C1s antibodies described herein are full-length IgG, Ig monomer, Fab fragment, F(ab’)2 fragment, Fd fragment, scFv, scAb, or Fv. In some embodiments, the humanized anti-C1s antibodies described herein are full-length IgG. In some embodiments, any heavy chain of the humanized anti-C1s antibodies described herein comprises a heavy chain constant region (CH) or a portion thereof (e.g., CH1, CH2, CH3, or combinations thereof). The heavy chain constant region can be of any suitable origin, such as human, mouse, rat, or rabbit. In some embodiments, the heavy chain constant region is from human IgG (gamma heavy chain), such as IgG1, IgG2, or IgG4.

[0071] In some embodiments, the mutations can be introduced into the heavy chain constant region of any one of the humanized anti-C1s antibodies described herein. In some embodiments, one, two, or more mutations (e.g., amino acid substitutions) are introduced into the heavy chain constant region (e.g., the CH2 domain (residues 231-340 of human IgG1) and / or the CH3 domain (residues 341-447 of human IgG1) and / or the hinge region, numbered according to the Kabat numbering system (e.g., the Kabat EU index)) to increase or decrease the affinity of the antibody for Fc receptors (e.g., activating Fc receptors) on the surface of effector cells. Mutations in the Fc region of an antibody that decrease or increase the affinity of the antibody for an Fc receptor, and techniques for introducing such mutations into an Fc receptor or a fragment thereof, are known to those of skill in the art. Examples of mutations in an antibody Fc receptor that can be made to alter the affinity of the antibody for the Fc receptor are described, for example, in Smith P et al., (2012) PNAS 109:6181-6186, U.S. Patent No. 6,737,056, and International Publication Nos. 02 / 060919, 98 / 23289, and 97 / 34631, which are incorporated herein by reference.

[0072] In some embodiments, one, two, or more mutations (e.g., amino acid substitutions) are introduced into the hinge region of the heavy chain constant region (CH1 domain) such that the number of cysteine residues in the hinge region changes (e.g., increases or decreases), as described, for example, in U.S. Patent No. 5,677,425. The number of cysteine residues in the hinge region of the CH1 domain can be altered, for example, to facilitate assembly of the light and heavy chains, or to modify (e.g., increase or decrease) the stability of the antibody, or to facilitate linker conjugation.

[0073] In some embodiments, one, two or more amino acid mutations (i.e., substitutions, insertions or deletions) are introduced into the IgG constant domain or its FcRn-binding fragment such that the in vivo half-life of the antibody is altered (e.g., decreased or increased). In some embodiments, one or more mutations are introduced into the Fc or hinge-Fc domain fragment. For examples of mutations that alter the in vivo half-life of an antibody (e.g., decrease or increase), see WO 02 / 060919; WO 98 / 23289; and WO 97 / 34631; and U.S. Pat. Nos. 5,869,046; 6,121,022; 6,277,375; and 6,165,745.

[0074] In some embodiments, the constant region antibody described herein is an IgG1 constant region and includes a substitution of methionine (M) at position 252 with tyrosine (Y), a substitution of serine (S) at position 254 with threonine (T), and a substitution of threonine (T) at position 256 with glutamic acid (E) (numbering according to the EU index as in Kabat). See U.S. Pat. No. 7,658,921, which is incorporated herein by reference. This type of mutant IgG, called the “YTE variant,” has been shown to exhibit a 4-fold increase in half-life compared to the wild-type version of the same antibody (see Dall’Acqua W F et al., (2006) J Biol Chem 281:23514-24). In some embodiments, the antibody includes an IgG constant domain that includes one, two, three or more amino acid substitutions of amino acid residues at positions 251-257, 285-290, 308-314, 385-389 and 428-436 (numbering according to the EU index as in Kabat). Additional mutations that can be introduced into the heavy chain constant region that are thought to extend the half-life of the antibody, such as the M428L / N434S (EU numbering; M459L / N466S Kabat numbering) mutation described in Zalevsky et al., Nat Biotechnol. 2010 Feb;28(2):157-159 are known in the art.

[0075] In some embodiments, one, two, or more amino acid substitutions are introduced into the Fc region of the IgG constant domain to alter the effector function of the antibody. Effector ligands whose affinity is altered can be, for example, Fc receptors or the C1 component of complement. This approach is described in more detail in U.S. Patent Nos. 5,624,821 and 5,648,260. In some embodiments, deletion or inactivation (via point mutation or other means) of the constant region domain can reduce Fc receptor binding of the circulating antibody, thereby increasing tumor localization. See, for example, U.S. Patent Nos. 5,585,097 and 8,591,886 for descriptions of mutations that delete or inactivate the constant domain and thereby enhance tumor localization. In some embodiments, at least one amino acid substitution is introduced into the Fc region of the antibodies described herein to remove potential glycosylation sites on the Fc region, whereby Fc receptor binding can be reduced (see, for example, Shields R L et al., (2001) J Biol Chem 276:6591-604).

[0076] In some embodiments, at least one amino acid within the constant region can be substituted with a different amino acid residue such that the antibody alters C1q binding and / or reduces or abrogates complement-dependent cytotoxicity (CDC). This approach is described in more detail in U.S. Patent No. 6,194,551 (Idusogie et al.). In some embodiments, at least one amino acid residue within the N-terminal region of the CH2 domain of the antibodies described herein is modified such that it alters the ability of the antibody to fix complement. This approach is further described in International Publication No. 94 / 29351 pamphlet. In some embodiments, the Fc region of the antibodies described herein is modified to increase the ability of the antibody to mediate antibody-dependent cell cytotoxicity (ADCC) and / or increase the affinity of the antibody for the Fcγ receptor. This approach is further described in International Publication No. 00 / 42072 pamphlet.

[0077] In some embodiments, to avoid potential complications due to Fab arm exchange, which is known to occur with native IgG4 mAbs, the antibodies provided herein may contain a stabilizing “Adair” mutation (Angal S., et al., “A single amino acid substitution abolishes the heterogeneity of chimeric mouse / human (IgG4) antibody,” Mol Immunol 30, 105 - 108; 1993), where serine 228 (EU numbering; residue 241 in Kabat numbering) is converted to proline, resulting in an IgG1-like hinge sequence. In some embodiments, to reduce residual antibody-dependent cellular cytotoxicity, a L235E (corresponding to L248E in EU numbering, Kabat numbering) mutation is introduced into the heavy chain constant region, as described, for example, in Benhnia et al., J. Virology, Dec. 2009, p. 12355 - 12367.

[0078] In some embodiments, the humanized anti-C1s antibody comprises a light chain complementarity determining region 1 (LC CDR1) comprising the amino acid sequence of KASQSVDYDGDSYMN (SEQ ID NO: 1). In some embodiments, the humanized anti-C1s antibody comprises a light chain complementarity determining region 2 (LC CDR2) comprising the amino acid sequence of DASNLES (SEQ ID NO: 2). In some embodiments, the humanized anti-C1s antibody comprises a light chain complementarity determining region 3 (LC CDR3) comprising the amino acid sequence of QQSNEDPWT (SEQ ID NO: 3). In some embodiments, the humanized anti-C1s antibody comprises an LC CDR1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3.

[0079] In some embodiments, the humanized anti-C1s antibody comprises a heavy chain complementarity determining region 1 (HC CDR1) that includes the amino acid sequence of DDYIH (SEQ ID NO: 4). In some embodiments, the humanized anti-C1s antibody comprises a heavy chain complementarity determining region 2 (HC CDR2) that includes the amino acid sequence of RIDPADGHTKYAPKFQV (SEQ ID NO: 5). In some embodiments, the humanized anti-C1s antibody comprises a heavy chain complementarity determining region 3 (HC CDR3) that includes the amino acid sequence of YGYGREVFDY (SEQ ID NO: 6). In some embodiments, the humanized anti-C1s antibody comprises an HC CDR1 that includes the amino acid sequence of SEQ ID NO: 4, an HC CDR2 that includes the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 that includes the amino acid sequence of SEQ ID NO: 6.

[0080] In some embodiments, the humanized anti-C1s antibody comprises an LC CDR1 that includes the amino acid sequence of SEQ ID NO: 1, an LC CDR2 that includes the amino acid sequence of SEQ ID NO: 2, an LC CDR3 that includes the amino acid sequence of SEQ ID NO: 3, an HC CDR1 that includes the amino acid sequence of SEQ ID NO: 4, an HC CDR2 that includes the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 that includes the amino acid sequence of SEQ ID NO: 6.

[0081] In some embodiments, the humanized anti-C1s antibody comprises a light chain variable region (VL) that includes the amino acid sequence of DIVLTQSPDSLAVSLGERATISCKASQSVDYDGDSYMNWYQQKPGQPPKILIYDASNLESGIPARFSGSGSGTDFTLTISSLEPEDFAIYYCQQSNEDPWTFGGGTKVEIK (SEQ ID NO: 7). In some embodiments, the humanized anti-C1s antibody comprises the LC CDR1, LC CDR2, and LC CDR3 of the VL that includes the amino acid sequence of SEQ ID NO: 7.

[0082] In some embodiments, the humanized anti-C1s antibody

Chemical Formula

[0083] In some embodiments, the humanized anti-C1s antibody comprises a VL comprising the amino acid sequence of SEQ ID NO: 7 and a VH comprising the amino acid sequence of SEQ ID NO: 8.

[0084] In some embodiments, the humanized anti-C1s antibody comprises LC CDR1, LC CDR2, and LC CDR3 of VL comprising the amino acid sequence of SEQ ID NO: 7, and HC CDR1, HC CDR2, and HC CDR3 of VH comprising the amino acid sequence of SEQ ID NO: 8.

[0085] In some embodiments, the humanized anti-C1s antibody

Chemical formula

[0086] In some embodiments, the humanized anti-C1s antibody

Chemical formula

[0087] In some embodiments, the humanized anti-C1s antibody comprises an LC comprising the amino acid sequence of SEQ ID NO: 9 and an HC comprising the amino acid sequence of SEQ ID NO: 10.

[0088] In some embodiments, the humanized anti-C1s antibody comprises an LC CDR1 comprising an amino acid sequence having 3 or fewer amino acid mutations (e.g., 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the LC CDR1 amino acid sequence of SEQ ID NO: 1. In some embodiments, the humanized anti-C1s antibody comprises an LC CDR2 comprising an amino acid sequence having 3 or fewer amino acid mutations (e.g., 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the LC CDR2 amino acid sequence of SEQ ID NO: 2. In some embodiments, the humanized anti-C1s antibody comprises an LC CDR3 comprising an amino acid sequence having 3 or fewer amino acid mutations (e.g., 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the LC CDR3 amino acid sequence of SEQ ID NO: 3.

[0089] In some embodiments, the humanized anti-C1s antibody comprises an HC CDR1 comprising an amino acid sequence having 3 or fewer amino acid mutations (e.g., 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the HC CDR1 amino acid sequence of SEQ ID NO: 4. In some embodiments, the humanized anti-C1s antibody comprises an HC CDR2 comprising an amino acid sequence having 3 or fewer amino acid mutations (e.g., 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the HC CDR2 amino acid sequence of SEQ ID NO: 5. In some embodiments, the humanized anti-C1s antibody comprises an HC CDR3 comprising an amino acid sequence having 3 or fewer amino acid mutations (e.g., 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the HC CDR3 amino acid sequence of SEQ ID NO: 6.

[0090] In some embodiments, the humanized anti-C1s antibody comprises a VL comprising an amino acid sequence having 20 or fewer amino acid mutations (e.g., 20 or fewer, 19 or fewer, 18 or fewer, 17 or fewer, 16 or fewer, 15 or fewer, 14 or fewer, 13 or fewer, 12 or fewer, 11 or fewer, 10 or fewer, 9 or fewer, 8 or fewer, 7 or fewer, 6 or fewer, 5 or fewer, 4 or fewer, 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the VL amino acid sequence of SEQ ID NO: 7.

[0091] In some embodiments, the humanized anti-C1s antibody comprises a VH comprising an amino acid sequence having 20 or fewer amino acid mutations (e.g., 20 or fewer, 19 or fewer, 18 or fewer, 17 or fewer, 16 or fewer, 15 or fewer, 14 or fewer, 13 or fewer, 12 or fewer, 11 or fewer, 10 or fewer, 9 or fewer, 8 or fewer, 7 or fewer, 6 or fewer, 5 or fewer, 4 or fewer, 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the VH amino acid sequence of SEQ ID NO: 8.

[0092] In some embodiments, the humanized anti-C1s antibody comprises a VL comprising an LC CDR1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, and an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, and comprises a framework region having 20 or fewer amino acid mutations (e.g., 20 or fewer, 19 or fewer, 18 or fewer, 17 or fewer, 16 or fewer, 15 or fewer, 14 or fewer, 13 or fewer, 12 or fewer, 11 or fewer, 10 or fewer, 9 or fewer, 8 or fewer, 7 or fewer, 6 or fewer, 5 or fewer, 4 or fewer, 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the VL sequence of SEQ ID NO: 7.

[0093] In some embodiments, the humanized anti-C1s antibody comprises a VH comprising an HC CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6, and comprises a framework region having 20 or fewer amino acid mutations (e.g., 20 or fewer, 19 or fewer, 18 or fewer, 17 or fewer, 16 or fewer, 15 or fewer, 14 or fewer, 13 or fewer, 12 or fewer, 11 or fewer, 10 or fewer, 9 or fewer, 8 or fewer, 7 or fewer, 6 or fewer, 5 or fewer, 4 or fewer, 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the VH sequence of SEQ ID NO: 8.

[0094] In some embodiments, the humanized anti-C1s antibody comprises (a) an LC CDR1 comprising the amino acid sequence of SEQ ID NO: 1, an LC CDR2 comprising the amino acid sequence of SEQ ID NO: 2, an LC CDR3 comprising the amino acid sequence of SEQ ID NO: 3, and a framework region containing 20 or fewer amino acid mutations (e.g., 20 or fewer, 19 or fewer, 18 or fewer, 17 or fewer, 16 or fewer, 15 or fewer, 14 or fewer, 13 or fewer, 12 or fewer, 11 or fewer, 10 or fewer, 9 or fewer, 8 or fewer, 7 or fewer, 6 or fewer, 5 or fewer, 4 or fewer, 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the VL sequence of SEQ ID NO: 7, and (b) an HC CDR1 comprising the amino acid sequence of SEQ ID NO: 4, an HC CDR2 comprising the amino acid sequence of SEQ ID NO: 5, an HC CDR3 comprising the amino acid sequence of SEQ ID NO: 6, and a framework region containing 20 or fewer amino acid mutations (e.g., 20 or fewer, 19 or fewer, 18 or fewer, 17 or fewer, 16 or fewer, 15 or fewer, 14 or fewer, 13 or fewer, 12 or fewer, 11 or fewer, 10 or fewer, 9 or fewer, 8 or fewer, 7 or fewer, 6 or fewer, 5 or fewer, 4 or fewer, 3 or fewer, 2 or fewer, or 1 or fewer amino acid mutations) relative to the VH sequence of SEQ ID NO: 8.

[0095] In some embodiments, the humanized anti-C1s antibody comprises a VL comprising an amino acid sequence having at least 80% (e.g., 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) identity to the VL amino acid sequence of SEQ ID NO: 7.

[0096] In some embodiments, the humanized anti-C1s antibody comprises a VH comprising an amino acid sequence having at least 80% (e.g., 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) identity to the VH amino acid sequence of SEQ ID NO: 8.

[0097] In some embodiments, the humanized anti-C1s antibody comprises a VL comprising an LC CDR1 having the amino acid sequence of SEQ ID NO: 1, an LC CDR2 having the amino acid sequence of SEQ ID NO: 2, and an LC CDR3 having the amino acid sequence of SEQ ID NO: 3, and comprises a framework region having at least 80% (e.g., 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) identity to the framework region of the VL sequence of SEQ ID NO: 7.

[0098] In some embodiments, the humanized anti-C1s antibody comprises a VH comprising an HC CDR1 having the amino acid sequence of SEQ ID NO: 4, an HC CDR2 having the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 having the amino acid sequence of SEQ ID NO: 6, and comprises a framework region having at least 80% (e.g., 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) identity to the framework region of the VH sequence of SEQ ID NO: 8.

[0099] In some embodiments, the humanized anti-C1s antibody comprises (a) a VL comprising an LC CDR1 having the amino acid sequence of SEQ ID NO: 1, an LC CDR2 having the amino acid sequence of SEQ ID NO: 2, and an LC CDR3 having the amino acid sequence of SEQ ID NO: 3, and comprises a framework region having at least 80% (e.g., 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) identity to the framework region of the VL sequence of SEQ ID NO: 7, and (b) a VH comprising an HC CDR1 having the amino acid sequence of SEQ ID NO: 4, an HC CDR2 having the amino acid sequence of SEQ ID NO: 5, and an HC CDR3 having the amino acid sequence of SEQ ID NO: 6, and comprises a framework region having at least 80% (e.g., 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%) identity to the framework region of the VH sequence of SEQ ID NO: 8.

[0100] In some embodiments, the heavy chain constant region in any one of the humanized anti-C1s antibodies described herein is an IgG4 constant region or a variant thereof. Examples of IgG4 constant regions and variants are provided in Table 1.

[0101]

Table 1

[0102] In some embodiments, any light chain of the humanized anti-C1s antibodies described herein may further comprise a light chain constant region (C L ). In some examples, C L is a kappa light chain. In other examples, C L is a lambda light chain. In some embodiments, C L is a kappa light chain, and its sequence is shown below. RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 14)

[0103] Other antibody heavy and light chain constant regions are well known in the art and are provided, for example, by the IMGT database (imgt.org) or vbase2.org / vbstat.php, all of which are hereby incorporated by reference into this specification.

[0104] Methods for treating CAD Cold agglutinin disease (CAD) is an autoimmune hemolytic anemia caused by IgM-induced classical complement pathway activation. The IgM autoantibodies in CAD are called cold agglutinins (CAg) because of their unique property of increased binding in response to a decrease in temperature. The CAg thermal amplitude is the highest temperature at which CAg can be detected reacting with red blood cell antigens and approaches core body temperature in many patients. The symptoms of CAD are typically caused by exposure to cold environmental temperatures (i.e., temperatures below core body temperature), viral infections, or inflammation. All patients with CAD have an active disease with varying levels of chronic ongoing hemolysis that causes anemia.

[0105] The present disclosure provides a method of treating CAD in a subject. In one aspect, the method includes administering an anti-C1s antibody to the subject at a fixed (or constant) dose of about 3 g to about 5 g. In some embodiments, the method includes administering an anti-C1s antibody to the subject at a fixed dose of about 3.5 g. In some embodiments, the method includes administering an anti-C1s antibody to the subject at a fixed dose of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 4.5 g.

[0106] In some embodiments, the antibody is administered about every 10, 12, 14, or 16 weeks. In some embodiments, the anti-C1s antibody is administered about every 12 weeks.

[0107] In some embodiments, the anti-C1s antibody is administered additionally about 4 weeks after the first administration. In some embodiments, about 3 g to about 5 g of the anti-C1s antibody is administered about 4 weeks after the first administration. In some embodiments, about 3.5 g of the anti-C1s antibody is administered about 4 weeks after the first administration. In some embodiments, about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 4.5 g of the anti-C1s antibody is administered about 4 weeks after the first administration.

[0108] In some embodiments, about 3 g to about 5 g of the antibody is administered on day 1 and then about every 10, 12, 14, or 16 weeks, and about 3 g to about 5 g of the antibody is administered additionally on day 29 or about day 29. In some embodiments, about 3 g to about 5 g of the antibody is administered intravenously on day 1 and then about every 10, 12, 14, or 16 weeks, and about 3 g to about 5 g of the antibody is administered additionally intravenously on day 29 or about day 29.

[0109] In some embodiments, about 3 g to about 5 g of the antibody is administered on day 1 and then about every 12 weeks, and about 3 g to about 5 g of the antibody is administered additionally on day 29 or about day 29. In some embodiments, about 3 g to about 5 g of the antibody is administered intravenously on day 1 and then about every 12 weeks, and about 3 g to about 5 g of the antibody is administered additionally intravenously on day 29 or about day 29.

[0110] In some embodiments, an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered on day 1 and then every about 10, 12, 14, or 16 weeks, and an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is additionally administered on day 29 or about day 29. In some embodiments, an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered intravenously on day 1 and then every about 10, 12, 14, or 16 weeks, and an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is additionally administered intravenously on day 29 or about day 29.

[0111] In some embodiments, an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered on day 1 and then every about 12 weeks, and an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is additionally administered on day 29 or about day 29. In some embodiments, an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered intravenously on day 1 and then every about 12 weeks, and an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is additionally administered intravenously on day 29 or about day 29.

[0112] In some embodiments, an antibody of about 3.5 g is administered on day 1 and then every about 10, 12, 14, or 16 weeks, and an antibody of about 3.5 g is additionally administered on day 29 or about day 29. In some embodiments, an antibody of about 3.5 g is administered intravenously on day 1 and then every about 10, 12, 14, or 16 weeks, and an antibody of about 3.5 g is administered intravenously on day 29 or about day 29.

[0113] In some embodiments, an antibody of about 3.5 g is administered on day 1 and then every about 12 weeks, and an antibody of about 3.5 g is additionally administered on day 29 or about day 29. In some embodiments, an antibody of about 3.5 g is administered intravenously on day 1 and then every about 12 weeks, and an antibody of about 3.5 g is administered intravenously on day 29 or about day 29.

[0114] In some embodiments, an anti-C1s antibody of about 3 g to about 5 g is administered to a subject every about 12 weeks for a period of about 12 weeks to 1 year, such as about 12 weeks to about 24 weeks, about 6 months to about 9 months, or about 6 months to 1 year. In some cases, an anti-C1s antibody of about 3 g to about 5 g is administered to the subject every about 12 weeks for a period exceeding 1 year. For example, in some embodiments, an anti-C1s antibody of about 3 g to about 5 g is administered to the subject every about 12 weeks for a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0115] In some embodiments, an anti-C1s antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered to a subject every about 12 weeks for a period of about 12 weeks to 1 year, such as about 12 weeks to about 24 weeks, about 6 months to about 9 months, or about 6 months to 1 year. In some cases, an anti-C1s antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered to the subject every about 12 weeks for a period exceeding 1 year. For example, in some embodiments, an anti-C1s antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered to the subject every about 12 weeks for a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0116] In some embodiments, an anti-C1s antibody of about 3.5 g is administered to a subject every about 12 weeks for a period of about 12 weeks to 1 year, such as about 12 weeks to about 24 weeks, about 6 months to about 9 months, or about 6 months to 1 year. In some cases, an anti-C1s antibody of about 3.5 g is administered to the subject every about 12 weeks for a period exceeding 1 year. For example, in some embodiments, an anti-C1s antibody of about 3.5 g is administered to the subject every about 12 weeks for a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0117] In some embodiments, an anti-C1s antibody of about 3 g to about 5 g is administered to a subject every about 12 weeks for a period of about 12 weeks to 1 year, such as about 12 weeks to about 24 weeks, about 6 months to about 9 months, or about 6 months to 1 year, and an antibody of about 3 g to about 5 g is additionally administered on the 29th day or about the 29th day. In some cases, an anti-C1s antibody of about 3 g to about 5 g is administered to the subject every about 12 weeks over a period of more than 1 year, and an antibody of about 3 g to about 5 g is additionally administered on the 29th day or about the 29th day. For example, in some embodiments, an anti-C1s antibody of about 3 g to about 5 g is administered to the subject every about 12 weeks for a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years, and an antibody of about 3 g to about 5 g is additionally administered on the 29th day or about the 29th day.

[0118] In some embodiments, an anti-C1s antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered to a subject every about 12 weeks for a period of about 12 weeks to 1 year, such as about 12 weeks to about 24 weeks, about 6 months to about 9 months, or about 6 months to 1 year, and an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is additionally administered on the 29th day or about the 29th day. In some cases, an anti-C1s antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered to the subject every about 12 weeks over a period of more than 1 year, and an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is additionally administered on the 29th day or about the 29th day. For example, in some embodiments, an anti-C1s antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is administered to the subject every about 12 weeks for a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years, and an antibody of about 3 g, about 3.5 g, about 4 g, about 4.5 g, or about 5 g is additionally administered on the 29th day or about the 29th day.

[0119] In some embodiments, about 3.5 g of the anti-C1s antibody is administered to a subject every about 12 weeks for a period of about 12 weeks to 1 year, such as about 12 weeks to about 24 weeks, about 6 months to about 9 months, or about 6 months to 1 year, and an additional dose of about 3.5 g of the antibody is administered on the 29th day or about the 29th day. In some cases, about 3.5 g of the anti-C1s antibody is administered to a subject every about 12 weeks over a period of more than 1 year, and an additional dose of about 3.5 g of the antibody is administered on the 29th day or about the 29th day. For example, in some embodiments, about 3.5 g of the anti-C1s antibody is administered to a subject every about 12 weeks for a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years, and an additional dose of about 3.5 g of the antibody is administered on the 29th day or about the 29th day.

[0120] In some embodiments, the present disclosure provides a method of treating CAD in a subject in need thereof, the method comprising administering to the subject an effective amount of an anti-C1s antibody, wherein the subject has a plasma concentration of the antibody of at least about 100 μg / mL, at least about 200 μg / mL, at least about 300 μg / mL, at least about 400 μg / mL, at least about 500 μg / mL, at least about 600 μg / mL, at least about 700 μg / mL, at least about 800 μg / mL, at least about 900 μg / mL, at least about 1000 μg / mL, at least about 1100 μg / mL, at least about 1200 μg / mL, or at least about 1300 μg / mL. The plasma concentration of the anti-C1s antibody in the subject can be measured using techniques known in the art. In some embodiments, the anti-C1s antibody is measured using a direct binding enzyme-linked immunosorbent assay (ELISA). In some embodiments, the anti-C1s antibody is measured using an indirect ELISA. In some embodiments, the anti-C1s antibody is measured using a sandwich ELISA. In some embodiments, the anti-C1s antibody is measured using a competitive ELISA.

[0121] In some embodiments, the present disclosure provides a method of increasing the number of reticulocytes in the blood of a subject having CAD, the method comprising administering an anti-C1s antibody to the subject. In some embodiments, the anti-C1s antibody, after administration, increases the number of reticulocytes in the blood of the subject by at least about 1.1-fold, at least about 1.2-fold, at least about 1.3-fold, at least about 1.4-fold, at least about 1.5-fold, at least about 1.6-fold, at least about 1.7-fold, at least about 1.8-fold, at least about 1.9-fold, at least about 2.0-fold, at least about 2.1-fold, at least about 2.2-fold, at least about 2.3-fold, at least about 2.4-fold, at least about 2.5-fold, at least about 2.6-fold, at least about 2.7-fold, at least about 2.8-fold, at least about 2.9-fold, at least about 3.0-fold, at least about 4-fold, at least about 5-fold, at least about 6-fold, at least about 7-fold, at least about 8-fold, at least about 9-fold, or at least about 10-fold.

[0122] In some embodiments, the anti-C1s antibody increases the number of reticulocytes in the blood of the subject within about 2 hours, within about 3 hours, within about 4 hours, within about 5 hours, within about 6 hours, within about 7 hours, within about 8 hours, within about 9 hours, within about 10 hours, within about 11 hours, within about 12 hours, within about 13 hours, within about 14 hours, within about 15 hours, within about 16 hours, within about 17 hours, within about 18 hours, within about 19 hours, within about 20 hours, within about 21 hours, within about 22 hours, within about 23 hours, within about 24 hours, within about 1 day, within about 2 days, within about 3 days, within about 4 days, within about 5 days, within about 6 days, within about 7 days, within about 8 days, within about 9 days, within about 10 days, within about 11 days, within about 12 days, within about 13 days, within about 14 days, within about 2 weeks, within about 3 weeks, within about 4 weeks, within about 5 weeks, within about 6 weeks, within about 7 weeks, within about 8 weeks, within about 9 weeks, within about 10 weeks, within about 11 weeks, or within about 12 weeks after administration.

[0123] In some embodiments, the present disclosure provides a method of reducing the level of lactate dehydrogenase (LDH) in a subject having CAD, the method comprising administering an anti-C1s antibody to the subject. In some embodiments, the anti-C1s antibody reduces the level of LDH to a substantially normal reference range (about 105 - 333 IU / L). In some embodiments, the anti-C1s antibody reduces the level of total bilirubin to about 333 IU / L or less.

[0124] In some embodiments, the anti-C1s antibody reduces the level of LDH in the subject within about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 1 day, about 2 days, about 3 days, about 4 days, about 5 days, about 6 days, about 7 days, about 8 days, about 9 days, about 10 days, about 11 days, about 12 days, about 13 days, about 14 days, about 2 weeks, about 3 weeks, about 4 weeks, about 5 weeks, about 6 weeks, about 7 weeks, about 8 weeks, about 9 weeks, about 10 weeks, about 11 weeks, or about 12 weeks from administration.

[0125] In some embodiments, the present disclosure provides a method of increasing the level of hemoglobin in a subject having CAD, the method comprising administering an anti-C1s antibody to the subject. In some embodiments, the anti-C1s antibody, after administration, increases the level of hemoglobin in the subject by at least about 1.0 g / dL, 1.1 g / dL, 1.2 g / dL, 1.3 g / dL, 1.4 g / dL, 1.5 g / dL, 1.6 g / dL, 1.7 g / dL, 1.8 g / dL, 1.9 g / dL, 2.0 g / dL, 2.1 g / dL, 2.2 g / dL, 2.3 g / dL, 2.4 g / dL, 2.5 g / dL, 2.6 g / dL, 2.7 g / dL, 2.8 g / dL, 2.9 g / dL, 3.0 g / dL, 3.1 g / dL, 3.2 g / dL, 3.3 g / dL, 3.4 g / dL, 3.5 g / dL, 3.6 g / dL, 3.7 g / dL, 3.8 g / dL, 3.9 g / dL, 4.0 g / dL, 4.1 g / dL, 4.2 g / dL, 4.3 g / dL, 4.4 g / dL, or 4.5 g / dL. In some embodiments, the anti-C1s antibody, after administration, increases the level of total hemoglobin in the subject to at least about 10.0 g / dL, at least about 10.1 g / dL, at least about 10.2 g / dL, at least about 10.3 g / dL, at least about 10.4 g / dL, at least about 10.5 g / dL, at least about 10.6 g / dL, at least about 10.7 g / dL, at least about 10.8 g / dL, at least about 10.9 g / dL, at least about 11.0 g / dL, at least about 11.1 g / dL, at least about 11.2 g / dL, at least about 11.3 g / dL, at least about 11.4 g / dL, at least about 11.5 g / dL, at least about 11.6 g / dL, at least about 11.7 g / dL, at least about 11.8 g / dL, at least about 11.9 g / dL, at least about 12.0 g / dL, at least about 12.1 g / dL, at least about 12.2 g / dL, at least about 12.3 g / dL, at least about 12.4 g / dL, at least about 12.5 g / dL, at least about 12.6 g / dL, at least about 12.7 g / dL, at least about 12.8 g / dL, at least about 12.9 g / dL, at least about 13.0 g / dL, at least about 13.1 g / dL, at least about 13.2 g / dL, at least about 13.3 g / dL, at least about 13.4 g / dL, at least about 13.Increase to at least about 5 g / dL, at least about 13.6 g / dL, at least about 13.7 g / dL, at least about 13.8 g / dL, at least about 13.9 g / dL, at least about 14.0 g / dL, at least about 14.1 g / dL, at least about 14.2 g / dL, at least about 14.3 g / dL, at least about 14.4 g / dL, at least about 14.5 g / dL, at least about 14.6 g / dL, at least about 14.7 g / dL, at least about 14.8 g / dL, at least about 14.9 g / dL, at least about 15.0 g / dL, at least about 15.1 g / dL, at least about 15.2 g / dL, at least about 15.3 g / dL, at least about 15.4 g / dL, at least about 15.5 g / dL, at least about 15.6 g / dL, at least about 15.7 g / dL, at least about 15.8 g / dL, at least about 15.9 g / dL, at least about 16.0 g / dL, at least about 16.1 g / dL, at least about 16.2 g / dL, at least about 16.3 g / dL, at least about 16.4 g / dL, at least about 16.5 g / dL, at least about 16.6 g / dL, at least about 16.7 g / dL, at least about 16.8 g / dL, at least about 16.9 g / dL, at least about 17.0 g / dL, at least about 17.1 g / dL, at least 17.2 g / dL, at least about 17.3 g / dL, at least about 17.4 g / dL, at least about 17.5 g / dL, at least about 17.6 g / dL, at least about 17.7 g / dL, at least about 17.8 g / dL, at least about 17.9 g / dL, or up to at least about 18.0 g / dL.

[0126] In some embodiments, the anti-C1s antibody increases the level of hemoglobin in a subject within about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, within about 1 day, within about 2 days, within about 3 days, within about 4 days, within about 5 days, within about 6 days, within about 7 days, within about 8 days, within about 9 days, within about 10 days, within about 11 days, within about 12 days, within about 13 days, within about 14 days, within about 2 weeks, within about 3 weeks, within about 4 weeks, within about 5 weeks, within about 6 weeks, within about 7 weeks, within about 8 weeks, within about 9 weeks, within about 10 weeks, within about 11 weeks, or within about 12 weeks from administration.

[0127] In some embodiments, the present disclosure provides a method of reducing the level of bilirubin in a subject having CAD, the method comprising administering an anti-C1s antibody to the subject. In some embodiments, the anti-C1s antibody reduces the level of total bilirubin to a substantially normal reference range (about 1.71 to about 20.5 μmol / L). In some embodiments, the anti-C1s antibody reduces the level of total bilirubin to about 20.5 μmol / L or less.

[0128] In some embodiments, the anti-C1s antibody reduces the level of total bilirubin in a subject within about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, within about 1 day, within about 2 days, within about 3 days, within about 4 days, within about 5 days, within about 6 days, within about 7 days, within about 8 days, within about 9 days, within about 10 days, within about 11 days, within about 12 days, within about 13 days, within about 14 days, within about 2 weeks, within about 3 weeks, within about 4 weeks, within about 5 weeks, within about 6 weeks, within about 7 weeks, within about 8 weeks, within about 9 weeks, within about 10 weeks, within about 11 weeks, or within about 12 weeks from administration.

[0129] In some embodiments, the present disclosure provides a method of inhibiting the classical complement pathway (e.g., in an individual's body fluid, tissue, or organ) by at least about 75%, at least about 80%, at least about 85%, or at least about 90% in a subject having CAD, the method comprising administering an anti-C1s antibody to the subject. In some embodiments, the classical complement pathway is inhibited by at least about 90%. In some embodiments, the classical complement pathway is inhibited by about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%. The level of activity of the classical complement pathway can be determined using any of a variety of methods. As one non-limiting example, the activity of the classical complement pathway can be determined ex vivo, for example, by determining the level of activity of the classical complement pathway in a blood, serum, or plasma sample obtained from an individual. For example, the classical complement pathway in a blood, serum, or plasma sample can be activated ex vivo, and the amount of complement component cleavage products (e.g., C5b-9) generated by such activation can be determined. In some embodiments, the level of activity of the classical complement pathway is determined using the Wieslab® Complement System Classical Pathway Assay.

[0130] In some embodiments, the anti-C1s antibody inhibits the classical complement pathway in a subject within about 1 hour, 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, within about 1 day, within about 2 days, within about 3 days, within about 4 days, within about 5 days, within about 6 days, within about 7 days, within about 8 days, within about 9 days, within about 10 days, within about 11 days, within about 12 days, within about 13 days, within about 14 days, within about 2 weeks, within about 3 weeks, within about 4 weeks, within about 5 weeks, within about 6 weeks, within about 7 weeks, within about 8 weeks, within about 9 weeks, within about 10 weeks, within about 11 weeks, or within about 12 weeks from administration.

[0131] In some embodiments, the present disclosure provides a method of reducing the 50% hemolytic complement activity (CH50) level in a subject having CAD, the method comprising administering an anti-C1s antibody to the subject. The CH50 assay is a standard clinical test used to measure the hemolytic ability of a serum sample mediated by complement. In some embodiments, the CH50 level decreases by about 10-20 IU / mL, about 10-15 IU / mL, or about 15-20 IU / mL. In some embodiments, the (CH50) level decreases by 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 IU / mL. In some embodiments, the (CH50) level decreases to less than about 10 IU / mL, less than about 9 IU / mL, less than about 8 IU / mL, less than about 7 IU / mL, less than about 6 IU / mL, or less than about 5 IU / mL.

[0132] In some embodiments, the anti-C1s antibody reduces the CH50 level in a subject within about 1 hour, within about 2 hours, within about 3 hours, within about 4 hours, within about 5 hours, within about 6 hours, within about 7 hours, within about 8 hours, within about 9 hours, within about 10 hours, within about 11 hours, within about 12 hours, within about 13 hours, within about 14 hours, within about 15 hours, within about 16 hours, within about 17 hours, within about 18 hours, within about 19 hours, within about 20 hours, within about 21 hours, within about 22 hours, within about 23 hours, within about 24 hours, within about 1 day, within about 2 days, within about 3 days, within about 4 days, within about 5 days, within about 6 days, within about 7 days, within about 8 days, within about 9 days, within about 10 days, within about 11 days, within about 12 days, within about 13 days, within about 14 days, within about 2 weeks, within about 3 weeks, within about 4 weeks, within about 5 weeks, within about 6 weeks, within about 7 weeks, within about 8 weeks, within about 9 weeks, within about 10 weeks, within about 11 weeks, or within about 12 weeks from administration.

[0133] In some embodiments, the inclusion criteria are as follows. Participants are male and female adults who are 18 years of age or older at the time of signing the informed consent and exhibit the following characteristics: 1. Diagnosis of CAD confirmed based on the following criteria: ● Chronic hemolysis; ● Polyspecific direct antiglobulin test (DAT) positive status; ● Monospecific DAT strongly positive for C3d; ● Cold agglutinin [CAg] titer of 64 or higher at 4°C; ● IgG DAT ≤ 1+; and ● No overt malignant disease 2. Hgb level ≤ 10.0 g / dL on both -42 days and -21 days of the screening period; if the patient received a transfusion during screening, the eligible Hgb value must be obtained at least 28 days after the transfusion. 3. Bilirubin levels above the normal reference range (including participants with Gilbert's syndrome) 4. Ferritin levels above the normal lower limit. If the participant has been receiving a stable dose for the past 4 weeks, co-treatment with iron supplementation is permitted. 5. The presence of at least moderate CAD-related fatigue based on the "Fatigue Screening" conducted on the -42nd day of the screening period. That is, the participant must report having moderate, severe, or very severe fatigue related to CAD in the past month.

[0134] In some embodiments, the methods of the present disclosure prevent or delay the onset of at least one symptom of CAD in a subject. In some embodiments, the compositions of the present disclosure reduce or eliminate at least one symptom of CAD in a subject. The symptom can also be the activity of C1s protein in the cells, tissues, or body fluids of an individual. The symptom can also be the degree of complement activation in the cells, tissues, or body fluids of an individual.

[0135] "Treatment" means at least alleviation of symptoms related to CAD, where alleviation is used in a broad sense to refer to at least a reduction in a parameter related to CAD, such as the magnitude of the symptom.

[0136] The baseline values of laboratory parameters related to anemia (Hgb) and hemolysis (bilirubin) and the baseline values related to fatigue (FACIT-Fatigue Scale Score) are defined as the average of the evaluations on the -21st day during the screening period and the 1st day before treatment administration. If a transfusion is performed during the screening period, the baseline measurement must be at least 28 days after the transfusion. In that case, the measurements within 28 days of the transfusion are considered invalid and are subsequently excluded, and the baseline value becomes the last valid measurement before treatment administration.

[0137] The primary treatment evaluation value of the test parameters related to anemia is the average of the non-missing measurement values of Hgb evaluated on the 141st day, 155th day, and 169th day [weeks 21, 23, and 25].

[0138] Endpoint response rate: The percentage of participants who achieved an increase of 2 g / dL or more from baseline based on the mean of Hgb values measured on days 141, 155, and 169 [weeks 21, 23, and 25], and who met both of two conditions: (1) no transfusions were given during the last 21 weeks; and (2) no CAD drugs prohibited by the protocol were used from baseline.

[0139] The primary treatment evaluation value of the FACIT-Fatigue Scale score measurement is the mean of the complete FACIT-Fatigue Scale scores evaluated simultaneously on days 141, 155, and 169. Endpoint: Change from baseline at the primary treatment evaluation time point for FACIT-Fatigue measurement.

[0140] There are three major secondary endpoints: 1. Change in bilirubin from baseline at the primary treatment evaluation time point; 2. Change in Hgb from baseline at day 29; and 3. Change in FACIT-Fatigue Scale score from baseline at day 29. Another secondary endpoint is the mean change in bilirubin from baseline at day 29.

[0141] Various hosts (the term "host" is used interchangeably herein with the terms "subject", "individual", and "patient") are treatable according to the methods of the present invention. Generally, such hosts are "mammals" or "mammalian", and these terms are used broadly to describe organisms belonging to the class Mammalia, including carnivores (e.g., cats), herbivores (e.g., cows, horses, and sheep), omnivores (e.g., dogs, goats, and pigs), rodents (e.g., mice, guinea pigs, and rats), and primates (e.g., humans, chimpanzees, and monkeys). In some embodiments, the host is an individual having a complement system, such as a mammal, fish, or invertebrate. In some embodiments, the host is a companion animal, farm animal, working animal, zoo animal, or laboratory animal of a mammal, fish, or invertebrate that includes a complement system. In some embodiments, the host is a human.

[0142] Methods for treating CIDP Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare immune-mediated disease of the peripheral nervous system, characterized by loss of myelin sheaths in motor and sensory nerves, presenting as weakness, hyporeflexia or areflexia, numbness, paresthesia and sensory ataxia, and showing a large involvement of sensory fibers.

[0143] The diagnosis of CIDP is usually established by electrophysiological evidence of peripheral nerve demyelination, excluding other causes of demyelinating polyneuropathy or diseases that may have similar symptoms. The expert consensus criteria commonly used for the diagnosis of CIDP are provided by the joint task force of the European Federation of Neurological Societies / Peripheral Nerve Society (EFNS / PNS) (2010) (Bergh Van den PYK., et al. European J. of Neurology 2010, 17:356 - 363), and the most recent revised version (2021) of these criteria is available (Van den Bergh et al. Eur J Neurol 2021;28(11):3556 - 3583).

[0144] Activation of the complement pathway is expected to play an important role in the pathophysiology of CIDP. In CIDP patients, this pathway, which is an enzymatic cascade, is induced by pathogenic autoantibodies, causing inflammatory damage and ultimately driving the demyelination and inflammatory processes of peripheral nerves that underlie dysfunction.

[0145] By more selectively targeting important mechanisms of the disease, the anti - C1s antibodies of the present disclosure have the potential to improve the efficacy profile across a broad population of CIDP, including patients resistant to standard of care (SOC) therapies.

[0146] The present disclosure provides a method for treating CIDP in a subject. CIDP can be typical or atypical (Doneddu et al., Curr Opin Neurol. 34(5):613 - 624(2021)). In some embodiments, CIDP may be typical CIDP. In some embodiments, CIDP may be atypical CIDP. In some embodiments, atypical CIDP may present as Lewis - Sumner syndrome (LSS). In some embodiments, atypical CIDP may be accompanied by pure motor CIDP. In one aspect, the method includes administering to the subject a loading dose of an anti - C1s antibody followed by one or more maintenance doses of the antibody.

[0147] In some embodiments, the loading dose is a dose based on body weight. In some embodiments, the loading dose of the antibody is about 50 mg per kg of the subject's body weight.

[0148] In some embodiments, the maintenance dose of the antibody is a fixed dose. In some embodiments, the maintenance dose of the antibody is from about 200 mg to about 800 mg. In some embodiments, the maintenance dose of the antibody is from about 200 mg to about 300 mg, from about 300 mg to about 400 mg, from about 200 mg to about 500 mg, from about 300 mg to about 600 mg, from about 400 mg to about 800 mg or from about 600 mg to about 800 mg. In some embodiments, the maintenance dose of the antibody is from about 300 mg to about 600 mg. In some embodiments, the maintenance dose of the antibody is about 300 mg, about 400 mg, about 500 mg, or about 600 mg. In some embodiments, the maintenance dose of the antibody is about 300 mg. In some embodiments, the maintenance dose of the antibody is about 600 mg.

[0149] In some embodiments, the maintenance dose of the antibody is a fixed dose. In some embodiments, the maintenance dose of the antibody is from about 200 mg to about 800 mg. In some embodiments, the maintenance dose of the antibody is from about 200 mg to about 300 mg, from about 300 mg to about 400 mg, from about 200 mg to about 500 mg, from about 300 mg to about 600 mg, from about 400 mg to about 800 mg, or from about 600 mg to about 800 mg. In some embodiments, the maintenance dose of the antibody is from about 300 mg to about 600 mg. In some embodiments, the maintenance dose of the antibody is about 300 mg, about 400 mg, about 500 mg, or about 600 mg. In some embodiments, the maintenance dose of the antibody is about 300 mg. In some embodiments, the maintenance dose of the antibody is about 600 mg.

[0150] In some embodiments, one or more maintenance doses are administered about once a week (i.e., weekly), every two weeks, every four weeks, or every twelve weeks.

[0151] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose administered about once a week starting from day 8. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose administered subcutaneously about once a week starting from day 8.

[0152] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of from about 200 mg to about 800 mg administered about once a week starting from day 8. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of from about 200 mg to about 800 mg administered subcutaneously about once a week starting from day 8.

[0153] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of from about 1000 mg to about 8000 mg administered every two weeks, every four weeks, or every twelve weeks starting from day 8 or day 29. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of from about 1000 mg to about 8000 mg administered subcutaneously every two weeks, every four weeks, or every twelve weeks starting from day 8 or day 29.

[0154] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 300 mg to about 600 mg every approximately one week starting from day 8. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 300 mg to about 600 mg administered subcutaneously every approximately one week starting from day 8.

[0155] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 1200 mg to about 7200 mg every approximately four weeks or every approximately twelve weeks starting from day 29. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 1200 mg to about 7200 mg administered subcutaneously every approximately four weeks or every approximately twelve weeks starting from day 29.

[0156] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 300 mg every approximately one week starting from day 8. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 300 mg administered subcutaneously every approximately one week starting from day 8.

[0157] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 600 mg every approximately one week starting from day 8. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 600 mg administered subcutaneously every approximately one week starting from day 8.

[0158] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 600 mg every approximately two weeks starting from day 8. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 600 mg administered subcutaneously every approximately two weeks starting from day 8.

[0159] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 1200 mg every about two weeks starting from day 8. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 1200 mg administered subcutaneously every about two weeks starting from day 8.

[0160] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 1200 mg every about four weeks starting from day 29. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 1200 mg administered subcutaneously every about four weeks starting from day 29.

[0161] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 2400 mg every about four weeks starting from day 29. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 2400 mg administered subcutaneously every about four weeks starting from day 29.

[0162] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 3600 mg every about twelve weeks starting from day 29. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 3600 mg administered subcutaneously every about twelve weeks starting from day 29.

[0163] In some embodiments, a loading dose is administered on day 1, followed by a maintenance dose of about 7200 mg every about twelve weeks starting from day 29. In some embodiments, the loading dose is administered intravenously on day 1, followed by a maintenance dose of about 7200 mg administered subcutaneously every twelve weeks starting from day 29.

[0164] In some embodiments, a maintenance dose of the anti-C1s antibody from about 200 mg to about 800 mg is administered to a subject once a week over a period of about 4 weeks to 1 year, such as about 4 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of the anti-C1s antibody from about 200 mg to about 800 mg is administered to a subject once a week over a period of more than 1 year. For example, in some embodiments, a maintenance dose of the anti-C1s antibody from about 200 mg to about 800 mg is administered to a subject once a week over a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0165] In some embodiments, a maintenance dose of the anti-C1s antibody from about 1000 mg to about 8000 mg is administered to a subject every 2 weeks, or every 4 weeks, or every about 12 weeks over a period of about 4 weeks to 1 year, such as about 4 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of the anti-C1s antibody from about 1000 mg to about 8000 mg is administered to a subject every 2 weeks, every 4 weeks, or every about 12 weeks over a period of more than 1 year. For example, in some embodiments, a maintenance dose of the anti-C1s antibody from about 1000 mg to about 8000 mg is administered to a subject every 2 weeks, or every 4 weeks, or every about 12 weeks over a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0166] In some embodiments, a maintenance dose of the anti-C1s antibody of about 300 mg to about 600 mg is administered to a subject once a week for a period of about 4 weeks to 1 year, such as about 4 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of the anti-C1s antibody of about 300 mg to about 600 mg is administered to a subject once a week for a period of more than 1 year. For example, in some embodiments, a maintenance dose of the anti-C1s antibody of about 300 mg to about 600 mg is administered to a subject once a week for a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0167] In some embodiments, a maintenance dose of the anti-C1s antibody of about 1200 mg to about 7200 mg is administered to a subject every 2 weeks, or every 4 weeks, or every 12 weeks for a period of about 4 weeks to 1 year, such as about 4 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of the anti-C1s antibody of about 1200 mg to about 7200 mg is administered to a subject every 2 weeks, or every 4 weeks, or every 12 weeks for a period of more than 1 year. For example, in some embodiments, a maintenance dose of the anti-C1s antibody of about 1200 mg to about 7200 mg is administered to a subject every 2 weeks, or every 4 weeks, or every 12 weeks for a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0168] In some embodiments, a maintenance dose of about 300 mg of the anti-C1s antibody is administered to a subject once a week over a period of about 4 weeks to 1 year, such as about 4 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of about 300 mg of the anti-C1s antibody is administered to a subject once a week over a period of more than 1 year. For example, in some embodiments, a maintenance dose of about 300 mg of the anti-C1s antibody is administered to a subject once a week over a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0169] In some embodiments, a maintenance dose of about 600 mg of the anti-C1s antibody is administered to a subject once a week or once every two weeks over a period of about 4 weeks to 1 year, such as about 4 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of about 600 mg of the anti-C1s antibody is administered to a subject once a week or once every two weeks over a period of more than 1 year. For example, in some embodiments, a maintenance dose of about 600 mg of the anti-C1s antibody is administered to a subject once a week or once every two weeks over a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0170] In some embodiments, a maintenance dose of about 1200 mg of the anti-C1s antibody is administered to a subject once every two weeks or once every four weeks over a period of about 4 weeks to 1 year, such as about 4 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of about 1200 mg of the anti-C1s antibody is administered to a subject once every two weeks or once every four weeks over a period of more than 1 year. For example, in some embodiments, a maintenance dose of about 1200 mg of the anti-C1s antibody is administered to a subject once every two weeks or once every four weeks over a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0171] In some embodiments, a maintenance dose of the anti-C1s antibody of about 2400 mg is administered to a subject every about 4 weeks over a period of about 4 weeks to 1 year, such as about 4 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of the anti-C1s antibody of about 2400 mg is administered to a subject every about 4 weeks over a period of more than 1 year. For example, in some embodiments, a maintenance dose of the anti-C1s antibody of about 2400 mg is administered to a subject every about 4 weeks over a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0172] In some embodiments, a maintenance dose of the anti-C1s antibody of about 3600 mg is administered to a subject every about 12 weeks over a period of about 12 weeks to 1 year, such as about 12 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of the anti-C1s antibody of about 3600 mg is administered to a subject every about 12 weeks over a period of more than 1 year. For example, in some embodiments, a maintenance dose of the anti-C1s antibody of about 3600 mg is administered to a subject every about 12 weeks over a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0173] In some embodiments, a maintenance dose of the anti-C1s antibody of about 7200 mg is administered to a subject every about 12 weeks over a period of about 12 weeks to 1 year, such as about 12 weeks to about 8 weeks, about 2 months to about 6 months, about 6 months to about 9 months, or about 6 months to 1 year. In some embodiments, a maintenance dose of the anti-C1s antibody of about 7200 mg is administered to a subject every about 12 weeks over a period of more than 1 year. For example, in some embodiments, a maintenance dose of the anti-C1s antibody of about 7200 mg is administered to a subject every about 12 weeks over a period of 1 year to 50 years, such as 1 year to 2 years, 2 years to 5 years, 5 years to 10 years, 10 years to 20 years, 20 years to 30 years, 30 years to 40 years, or 40 years to 50 years.

[0174] In some embodiments, a single intravenous loading dose of 50 mg / kg is administered on day 1, and the subcutaneous (SC) dose is administered using a syringe, or a prefilled syringe, or an autoinjector, or a large volume drug delivery system. In some embodiments, the SC dose administered is 300 mg qw, 600 mg qw, 600 mg q2w, 1200 mg q2w, 1200 mg q4w, 2400 mg q4w, 3600 mg q12w, or 7200 mg q12w. In some embodiments, the SC dose is administered using a syringe, or a prefilled syringe, or an autoinjector, or a large volume drug delivery system until the end of treatment.

[0175] In some embodiments, the subject is resistant to another CIDP treatment and is also referred to herein as "standard of care (SOC) resistant". SOC-resistant patients are patients who have evidence of failure or inappropriate response to SOC, and who have no clinically significant improvement after at least 12 weeks of treatment with SOC and have a cause and treatment of inflammatory neuropathy (INCAT) score of 2 or more (Hughes et al. Ann Neurol. 2001;50(2):195-201), or who cannot receive or continue treatment with immunoglobulin or corticosteroid due to side effects. In some embodiments, clinically significant improvement (and worsening) is defined as, respectively, one of the following: a decrease (increase) of 1 point or more in the adjusted INCAT score, an increase (decrease) of 4 points or more in the total score of the inflammatory Rasch-built overall disability scale (I-RODS) (van Nes et al. Neurology. 2011;76(4):337-45), an increase (decrease) of 3 points or more in the Medical Research Council (MRC) total score, an improvement (decrease) of 8 kilopascals or more in the average grip strength (one hand), or an equivalent improvement (worsening) based on the information recorded in the medical record.

[0176] In some embodiments, the subject has been treated with another CIDP treatment, also referred to herein as "SOC treatment". In some embodiments, the subject has received another CIDP treatment within about one week of the loading dose or is receiving another CIDP treatment concurrently. SOC-treated patients are receiving stable SOC therapy, and evidence of an objective and clinically meaningful response is documented, and evidence of a clinically meaningful worsening due to interruption or dose reduction of SOC therapy is shown. In some embodiments, a clinically meaningful improvement (and worsening) is defined as one of the following, respectively: a decrease (increase) of 1 point or more in the adjusted INCAT score, an increase (decrease) of 4 points or more in the total I-RODS score, an increase (decrease) of 3 points or more in the MRC total score, an improvement (decrease) of 8 kilopascals or more in the average grip strength (one hand), or an equivalent improvement (worsening) based on information recorded in the medical record.

[0177] In some embodiments, the subject is treatment-naive for CIDP, also referred to herein as "treatment-naive for SOC". Treatment-naive patients are patients who have not previously received treatment for CIDP or who have been administered immunoglobulin (IVIg or SCIg) or corticosteroids but had the treatment discontinued for reasons other than lack of response or side effects. The patient must not have received treatment with immunoglobulin (IVIG or SCIG) or corticosteroids for at least 6 months prior to screening.

[0178] The other CIDP treatment can be any known CIDP treatment. In some embodiments, the other CIDP treatment is intravenous immunoglobulin (IVIG), subcutaneous immunoglobulin (SCIg), corticosteroids (e.g., prednisone, prednisolone, methylprednisolone), cyclophosphamide, rituximab, tocilizumab, azathioprine, tacrolimus, plasma exchange, mycophenolate mofetil, cyclosporine, plasma exchange, or a combination thereof. Corticosteroid treatment can be oral or intravenous.

[0179] In some embodiments, administration of the anti-C1s antibody improves the adjusted INCAT disability score. In some embodiments, administration of the anti-C1s antibody reduces the INCAT score by 1 point or more. In some embodiments, the subject is SOC-resistant. In some embodiments, the subject is naive to SOC. The INCAT disability scale is a validated tool for measuring disability in patients with CIDP. This has been used in large clinical trials leading to the approval of IVIg and SCIg (PATH). The total INCAT score is obtained by adding points corresponding to the arm and leg segments.

[0180] In some embodiments, the primary endpoint is the percentage of participants with an adjusted INCAT score that is 1 point or more lower than baseline (response) at week 24. The adjusted INCAT disability score is the same as the INCAT disability score, except for the exclusion of changes from 0 (normal) to 1 (minor symptoms or signs of one or both arms are excluded but do not affect any of the functions listed on the scale) or from 1 to 0 in upper limb function.

[0181] In some embodiments, the inclusion and exclusion criteria are as follows. Participants are adult men and women (18 years of age or older) with CIDP or possible CIDP criteria, based on the EAN / PNS Task Force CIDP guidelines, version 2 (2021). Participants with CIDP must have definite CIDP, pure motor CIDP, or Lewis-Sumner syndrome and must not have other polyneuropathies including pure sensory CIDP or distal CIDP.

[0182] Participants are i. Must have responded to IVIG in the past. The response must be an objective clinically significant improvement defined by at least one of the following: a decrease of 1 point or more in the adjusted INCAT score, an increase of 4 points or more in the total I-RODS score, an increase of 3 points or more in the total MRC score, an improvement of 8 kilopascals or more in the average grip strength (one hand), or an equivalent improvement based on the information recorded in the medical record and the judgment of the PI. ii. Must be receiving treatment with IVIg within 20% of the standard maintenance dosing regimen. The standard maintenance dose is defined as 0.4 - 1 g / kg every 2 - 6 weeks (EAN / PNS 2021 guidelines). iii. Must have been administered a stable maintenance dose of IVIg defined as no more than a 10% change in the frequency or dose of IVIG within 8 weeks prior to screening and must have remained stable until baseline. iv. Must have a residual disability defined as an adjusted INCAT score at screening confirmed at baseline of 2 - 9. v. Must have been previously vaccinated against encapsulated organisms.

[0183] In some embodiments, administration of the anti - C1s antibody prevents recurrence. Recurrence is defined as an increase of 1 or more in the adjusted INCAT disability score. In some embodiments, administration of the anti - C1s antibody prevents recurrence after discontinuation of another CIDP treatment.

[0184] In some embodiments, administration of the anti - C1s antibody improves the total MRC score by 3 points or more.

[0185] In some embodiments, administration of the anti - C1s antibody improves the I - RODS score by 4 points or more.

[0186] In some embodiments, administration of the anti - C1s antibody improves the average grip strength (e.g., one hand) by 8 kilopascals or more.

[0187] In some embodiments, the present disclosure provides a method of treating CIDP in a subject in need thereof, the method comprising administering to the subject an effective amount of an anti-C1s antibody, wherein the subject has a plasma concentration of the antibody of at least about 100 μg / mL, at least about 200 μg / mL, at least about 300 μg / mL, at least about 400 μg / mL, at least about 500 μg / mL, at least about 600 μg / mL, at least about 700 μg / mL, at least about 800 μg / mL, at least about 900 μg / mL, at least about 1000 μg / mL, at least about 1100 μg / mL, at least about 1200 μg / mL, at least about 1300 μg / mL, at least about 1400 μg / mL, or at least about 1500 μg / mL. The plasma concentration of the anti-C1s antibody in the subject can be measured using techniques known in the art. In some embodiments, the anti-C1s antibody is measured using a direct binding enzyme-linked immunosorbent assay (ELISA). In some embodiments, the anti-C1s antibody is measured using an indirect ELISA. In some embodiments, the anti-C1s antibody is measured using a sandwich ELISA. In some embodiments, the anti-C1s antibody is measured using a competitive ELISA.

[0188] In some embodiments, the present disclosure provides a method of inhibiting the classical complement pathway (e.g., in an individual's body fluid, tissue, or organ) by at least about 75%, at least about 80%, at least about 85%, or at least about 90% in a subject having CIDP, the method comprising administering an anti-C1s antibody to the subject. In some embodiments, the classical complement pathway is inhibited by at least about 90%. In some embodiments, the classical complement pathway is inhibited by about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%. The activity level of the classical complement pathway can be determined using any of a variety of methods. As one non-limiting example, the activity of the classical complement pathway can be determined ex vivo, for example, by determining the activity level of the classical complement pathway in a blood, serum, or plasma sample obtained from an individual. For example, the classical complement pathway in a blood, serum, or plasma sample can be activated ex vivo, and the amount of complement component cleavage products (e.g., C5b-9) generated by such activation can be determined. In some embodiments, the activity level of the classical complement pathway is determined using the Wieslab® Complement System Classical Pathway Assay.

[0189] In some embodiments, the anti-C1s antibody inhibits the classical complement pathway in the subject within about 1 hour, within 2 hours, within about 3 hours, within about 4 hours, within about 5 hours, within about 6 hours, within about 7 hours, within about 8 hours, within about 9 hours, within about 10 hours, within about 11 hours, within about 12 hours, within about 13 hours, within about 14 hours, within about 15 hours, within about 16 hours, within about 17 hours, within about 18 hours, within about 19 hours, within about 20 hours, within about 21 hours, within about 22 hours, within about 23 hours, within about 24 hours, within about 1 day, within about 2 days, within about 3 days, within about 4 days, within about 5 days, within about 6 days, within about 7 days, within about 8 days, within about 9 days, within about 10 days, within about 11 days, within about 12 days, within about 13 days, within about 14 days, within about 2 weeks, within about 3 weeks, within about 4 weeks, within about 5 weeks, within about 6 weeks, within about 7 weeks, within about 8 weeks, within about 9 weeks, within about 10 weeks, within about 11 weeks, or within about 12 weeks from administration.

[0190] In some embodiments, the present disclosure provides a method of reducing the 50% hemolytic complement activity (CH50) level in a subject having CIDP, the method comprising administering an anti-C1s antibody to the subject. The CH50 assay is a standard clinical test used to measure the hemolytic ability of a serum sample mediated by complement. In some embodiments, the CH50 level decreases by about 10 - 20 IU / mL, about 10 - 15 IU / mL, or about 15 - 20 IU / mL. In some embodiments, the (CH50) level decreases by 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 IU / mL. In some embodiments, the (CH50) level decreases to less than about 10 IU / mL, less than about 9 IU / mL, less than about 8 IU / mL, less than about 7 IU / mL, less than about 6 IU / mL, or less than about 5 IU / mL.

[0191] In some embodiments, the anti-C1s antibody reduces the CH50 level in the subject within about 1 hour, 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, within about 1 day, within about 2 days, within about 3 days, within about 4 days, within about 5 days, within about 6 days, within about 7 days, within about 8 days, within about 9 days, within about 10 days, within about 11 days, within about 12 days, within about 13 days, within about 14 days, within about 2 weeks, within about 3 weeks, within about 4 weeks, within about 5 weeks, within about 6 weeks, within about 7 weeks, within about 8 weeks, within about 9 weeks, within about 10 weeks, within about 11 weeks, or within about 12 weeks from administration.

[0192] In some embodiments, the methods of the present disclosure prevent or delay the onset of at least one symptom of CIDP in a subject. In some embodiments, the compositions of the present disclosure reduce or eliminate at least one symptom of CIDP in a subject. The symptom can also be the activity of C1s protein in the cells, tissues, or body fluids of an individual. The symptom can also be the degree of complement activation in the cells, tissues, or body fluids of an individual.

[0193] "Treatment" means at least alleviation of symptoms associated with CIDP, where alleviation is used in a broad sense to refer to at least a reduction in a parameter associated with CIDP, such as the magnitude of a symptom.

[0194] A variety of hosts (the term "host" is used interchangeably herein with the terms "subject", "individual", and "patient") can be treated according to the methods of the invention. Generally, such hosts are "mammals" or "mammalian", and these terms are used broadly to describe organisms belonging to the class Mammalia, including carnivores (e.g., cats), herbivores (e.g., cows, horses, and sheep), omnivores (e.g., dogs, goats, and pigs), rodents (e.g., mice, guinea pigs, and rats), and primates (e.g., humans, chimpanzees, and monkeys). In some embodiments, the host is an individual having a complement system, such as a mammal, fish, or invertebrate. In some embodiments, the host is a companion animal, farm animal, working animal, zoo animal, or laboratory animal of a mammal, fish, or invertebrate that includes a complement system. In some embodiments, the host is a human.

[0195] Composition Anti-C1s antibodies are generally present in a composition, such as a pharmaceutical composition. The humanized anti-C1s antibodies of the present disclosure can be formulated into a pharmaceutical composition by combining them with a suitable pharmaceutically acceptable carrier, pharmaceutically acceptable diluent, or other pharmaceutically acceptable excipient.

[0196] Exemplary antibody concentrations in the compositions of the present disclosure can range from about 50 mg / mL to about 250 mg / mL, from about 75 mg / mL to about 225 mg / mL, from about 100 mg / mL to about 200 mg / mL, from about 100 mg / mL to about 150 mg / mL, from about 150 mg / mL to about 200 mg / mL, from about 125 mg / mL to about 175 mg / mL, or from about 140 mg / mL to about 160 mg / mL. In some embodiments, the antibody concentration in the compositions of the present disclosure is about 50 mg / mL, about 75 mg / mL, about 100 mg / mL, about 125 mg / mL, about 130 mg / mL, about 140 mg / mL, about 150 mg / mL, about 160 mg / mL, about 170 mg / mL, about 175 mg / mL, about 200 mg / mL, or about 250 mg / mL. In some embodiments, the compositions of the present disclosure comprise a humanized anti-C1s antibody at about 150 mg / mL.

[0197] In some embodiments, the compositions comprising an anti-C1s antibody comprise one or more of a stabilizer, a buffer, a cryoprotectant, a chelating agent, and a surfactant.

[0198] Suitable stabilizers include arginine or its salts (e.g., arginine citrate, arginine hydrochloride, arginine oxalate, arginine phosphate, arginine succinate, or arginine tartrate), sugars, sugar alcohols, or amino sugars (e.g., fructose, galactose, glucose, lactose, maltose, mannose, raffinose, sorbitol, sorbose, sucrose, galactosamine, glucosamine, N-methylglucosamine, and neuraminic acid). Other stabilizers may also be used.

[0199] Suitable buffers include acetates, citrates, histidines, oxalates, phosphates, succinates, tartrates. Other buffers may also be used.

[0200] Suitable cryoprotectants include sucrose, ethylene glycol, dimethyl sulfoxide (DMSO), glycerol, trehalose, propylene glycol. Other cryoprotective agents may also be used.

[0201] Suitable chelating agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), dihydroxyethylglycine, citric acid, tartaric acid, and methionine. Other chelating agents may also be used.

[0202] Suitable surfactants include polysorbates (e.g., polysorbate 20 (PS20), polysorbate 40 (PS40), polysorbate 60 (PS60), and polysorbate 80 (PS80)), dicarboxylic acids, oxalic acid, succinic acid, fumaric acid, phthalic acid, polyoxyethylene sorbitan monooleate, poloxamers (e.g., P188), and polyethylene glycol. Other surfactants may also be used.

[0203] The compositions of the present disclosure can have a pH of from about 6 to about 7.5, from about 6 to about 7, from about 6.5 to about 7.5, or from about 6.5 to about 7.1. In some embodiments, the compositions of the present disclosure have a pH of about 6.0, about 6.1, about 6.2, about 6.3, about 6.4, about 6.5, about 6.6, about 6.7, about 6.8, about 6.9, about 7.0, about 7.1, about 7.2, about 7.3, about 7.4, or about 7.5. In some embodiments, the compositions of the present disclosure have a pH of from about 6.5 to 7.1. In some embodiments, the compositions of the present disclosure have a pH of about 6.8.

[0204] The compositions of the present disclosure can include other excipients including, but not limited to, water for injection, diluents, solubilizers, emollients, additional buffers, inorganic or organic salts, antioxidants, etc. Pharmaceutically acceptable excipients are generally readily available. In some embodiments, the compositions of the present disclosure do not include other excipients except those described above. Other pharmaceutically acceptable carriers or excipients (e.g., Remington’s Pharmaceutical Sciences 16 th(as described in Osol, A. Ed. (1980)) may be included in the formulation, provided that they do not adversely affect the desired properties of the formulation. In some embodiments, preservatives may be added. In some embodiments, the composition is substantially free of preservatives. Lyophilized formulations may contain cryoprotectants or lyoprotectants.

[0205] The compositions of the present disclosure can be in liquid form, lyophilized form (lyophilized preparations are reconstituted with a sterile solution prior to administration), or liquid form reconstituted from lyophilized form. Standard procedures for reconstituting lyophilized compositions involve adding a fixed volume of pure water (typically equivalent to the volume removed during lyophilization), but solutions containing antibacterial agents can be used to produce pharmaceutical compositions for parenteral administration; see also Chen (1992) Drug Dev Ind Pharm 18, 1311 - 54. In some embodiments, the compositions of the present disclosure are in liquid form. Liquid formulations may be injectable as is or may be diluted prior to injection.

[0206] Route of Administration The antibodies of the present disclosure can be administered to a subject using any available conventional methods and routes suitable for the delivery of conventional drugs, including systemic or local routes. Generally, the routes of administration contemplated in the present disclosure include, but are not necessarily limited to, enteral, parenteral, or inhalation routes.

[0207] Parenteral routes of administration other than inhalation include local, transdermal, subcutaneous, intramuscular, intraorbital, intra-articular, intraspinal, intrasternal, intrathecal, and intravenous routes, i.e., any route of administration other than through the gastrointestinal tract, but are not necessarily limited thereto. Parenteral administration can be performed so as to achieve systemic or local delivery of the subject antibody. When systemic delivery is desired, administration typically involves local or mucosal administration of the pharmaceutical preparation with an invasive or systemic absorbability.

[0208] The route of administration may be combined as needed or adjusted according to the desired effect. The antibody can be administered as a single dose or multiple doses. In some embodiments, the antibodies of the present disclosure are administered intravenously. In some embodiments, the antibodies of the present disclosure are administered subcutaneously.

[0209] The present invention also provides a pharmaceutical unit dosage form comprising a therapeutically effective amount of the composition of the present invention for treating one or more complement-mediated diseases in a subject by administering to the subject. In some embodiments, the subject is a human. The term "pharmaceutical unit dosage form" refers to physically discrete units appropriate as a unit dose for the subject being treated, each unit containing a predetermined amount of the active compound calculated to produce the desired therapeutic / preventive effect.

[0210] The unit dosage form may be a container containing the formulation. Suitable containers include, but are not limited to, sealed ampoules, vials (e.g., glass vials), bottles, syringes, and test tubes. The container can be formed from various materials such as glass or plastic and may have a sterile access port (e.g., the container may be a vial with a stopper that can be pierced with a hypodermic needle). In some embodiments, the container is a vial. In some embodiments, the container is a pre-filled syringe. Generally, the container needs to maintain the sterility and stability of the formulation.

[0211] Exemplary drug delivery devices can include needle-based injection systems as described in Table 1 of Section 5.2 of ISO 11608-1:2022. As described in ISO 11608-1:2022(E), needle-based injection systems can be broadly classified into multiple-dose container systems and single-dose (partial or full discharge) container systems. The container can be an exchangeable container or an integrated non-exchangeable container.

[0212] As further described in ISO 11608-1:2022(E), a multi-dose container system may include a needle-based injection device with an interchangeable container. In such a system, each container holds multiple doses and its size may be fixed or variable (pre-set by the user). Other multi-dose container systems may include a needle-based injection device with a non-interchangeable container incorporated therein. In such a system, each container holds multiple doses and its size may be fixed or variable (pre-set by the user).

[0213] As further described in ISO 11608-1:2022(E), a single-dose container system may include a needle-based injection device with an interchangeable container. In one example of such a system, each container holds a single dose, whereby the entire deliverable volume is discharged (full discharge). In a further example, each container holds a single dose, whereby a portion of the deliverable volume is discharged (partial discharge). Also as further described in ISO 11608-1:2022(E), a single-dose container system may include a needle-based injection device with a non-interchangeable container incorporated therein. In one example of such a system, each container holds a single dose, whereby the entire deliverable volume is discharged (full discharge). In a further example, each container holds a single dose, whereby a portion of the deliverable volume is discharged (partial discharge).

[0214] An exemplary sleeve-triggered auto-injector with manual needle insertion is described in WO 2015 / 004052. Examples of audible administration end feedback mechanisms are described in WO 2016 / 193346 and WO 2016 / 193348. Examples of needle safety mechanisms after use of an auto-injector are described in WO 2016 / 193352. Examples of needle sheath removal mechanisms for syringe auto-injectors are described in WO 2016 / 193353. Examples of support mechanisms for supporting the axial position of a syringe are described in WO 2016 / 193355.

[0215] Kit and Product The present disclosure provides a kit or product comprising the compositions of the present disclosure. The kit or product comprises a container containing an antibody of the present disclosure. The kit or product may further comprise one or more containers containing pharmaceutically acceptable excipients and may include other materials desirable from a commercial and user perspective, including filters, needles, and syringes. Instructions normally included in the commercial packages of therapeutic, prophylactic, or diagnostic products can be attached to the kit, which include, for example, information regarding indications, methods of use, dosages, manufacture, administration, contraindications, and / or warnings regarding the use of such therapeutic, prophylactic, or diagnostic products. The kit can also be associated with a label which can be any kind of data carrier containing information (e.g., leaflet, sticker, chip, printout, or barcode). In certain embodiments, the above instructions can be included in or on the label. The kit can further comprise a device for administering the formulation, in particular a device containing the composition, i.e., a filled syringe or a filled autoinjector, etc., but not limited thereto. The kit can also include a filled container containing the antibody, i.e., a filled vial, cartridge, sachet, or ampule, etc.

Example

[0216] Example 1. First-in-Human Trial with SAR445088 SAR445088 is a humanized monoclonal antibody that selectively inhibits activated C1s, prevents the enzymatic action of C1 on its substrates C4 and C2, and thus inhibits the formation of the classical pathway C3 convertase C4b2a. SAR445088 inhibits the downstream signaling cascade of the complement system that occurs via the CP, while the alternative pathway (AP) and the lectin pathway continue to function.

[0217] SAR445088 contains a serine-proline mutation (S241P) that stabilizes the core hinge region of the molecule, a leucine-glutamic acid mutation (L248E) that suppresses Fcγ receptor binding, and methionine-leucine (M428L) and asparagine-serine (N434S) mutations that enhance neonatal Fc receptor (FcRn) binding affinity and extend the half-life. The LC CDR1, LC CDR2, LC CDR3, HC CDR1, HC CDR2, HC CDR3, VH, VL, and heavy and light chain sequences of SAR445088 are described elsewhere in this application as SEQ ID NOs: 1-10. The sequences are also described in U.S. Patent No. 9,512,233, U.S. Patent No. 10,729,767, and U.S. Patent Application Publication No. 2020 / 0048332, each of which is incorporated herein by reference in its entirety.

[0218] In preclinical studies, SAR445088 demonstrated a stepwise inhibition-concentration relationship. In this first-in-human (FIH) clinical trial, the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) profiles of single intravenous (IV) and subcutaneous (SC) administrations and multiple SC administrations of SAR445088 in healthy participants were investigated.

[0219] Methods Study Design This FIH study was a single-site, double-blind, randomized, placebo-controlled, integrated single ascending dose (SAD; Part 1) and multiple ascending dose (MAD; Part 2) study of SAR445088 in healthy participants, including a Japanese cohort. In Part 1, nine dose cohorts of eight participants each (IV: 2, 4, 8, 16, 30, and 50 mg / kg; SC: 300, 600, and 1200 mg) were planned and randomized in a 3:1 ratio of SAR445088 (n = 6) to matched placebo (n = 2). For Part 2, three cohorts of ten participants each were planned and randomized in a 4:1 ratio of SAR445088 (n = 8) to matched placebo (n = 2). Participants in Part 2 were administered SAR445088 or placebo either once weekly for 4 weeks at 300 or 600 mg SC or once daily for 3 consecutive days at 600 mg.

[0220] This study enrolled healthy male and female participants (age: 18 - 50 years, weight: 45.0 - 110.0 kg, and body mass index: 18 - 32 kg / m 2 ) who had not received vaccinations against capsular bacterial pathogens such as meningococcus within 5 years prior to enrollment, which was performed during the screening period.

[0221] Study Objectives The primary objective of the study was to evaluate the safety and tolerability of SAR445088 in healthy participants. Secondary objectives included the evaluation of PK and PD profiles and immunogenicity.

[0222] Safety Evaluation Safety evaluations included physical examinations, clinical laboratory tests, serum tests (including SLE panel), urine analysis, vital signs, anti-drug antibodies (ADA), adverse events (AES), and electrocardiograms (ECG).

[0223] Biological Analytic Methods Quantification of SAR445088: SAR445088 in plasma was measured using a high-performance liquid chromatography assay with tandem mass spectrometry (MS / MS) detection. An immunoaffinity approach was used to concentrate SAR445088 from human plasma using protein G-coated magnetic beads. The bound protein was subjected to on-bead proteolysis with trypsin according to standard protein denaturation, reduction, and alkylation steps. As a result of trypsin digestion, the SAR445088 concentration was determined using characteristic peptide fragments generated as surrogates. The lower limit of quantification (LLOQ) was 10 μg / mL.

[0224] Wieslab CP assay: An enzyme-linked immunosorbent assay (ELISA) was used for the quantitative determination of complement activation in serum. The LLOQ was 10% activity.

[0225] Complement-mediated hemolytic capacity (CH50) assay: CH50 was measured using an in vitro automated homogeneous liposome-based assay (Fujifilm Wako) for the quantitative determination of total complement activity in human serum. The LLOQ of this assay was 10 IU / mL.

[0226] Estimation of anti-drug antibody (ADA): The presence of ADA in plasma was evaluated using an electrochemiluminescence immunoassay (PPD Laboratories, Richmond, VA).

[0227] C4: The estimation of C4 was quantitatively evaluated using a commercially available in vitro diagnostic (Beckman Coulter, Brea, CA) assay kit from Gen X Laboratories Inc (Los Angeles, CA). The LLOQ of this assay was 8 mg / dL.

[0228] Wieslab alternative pathway (AP) assay: A qualitative determination of functional complement AP in human serum with an LLOQ of 10% was performed using an ELISA assay.

[0229] Pharmacokinetic evaluation: PK parameters were calculated by non-compartmental analysis. The plasma concentration and PK of SAR445088 were summarized by descriptive statistics (mean, geometric mean, median, standard deviation [SD], standard error of the mean (SEM), and coefficient of variation (CV), minimum and maximum values, etc.) for each dose level and each route (IV and SC) using PKDMS (in-house software) version 3.1 and Phoenix WinNonLin Professional version 8.1. The data were also summarized by the relevant ADA status. For each presentation, the mean concentration and PK parameter values are arithmetic means unless otherwise specified. In the calculation of the mean value, concentration values below the plasma assay limit were treated as zero. The quantitation limit (BLQ) data after the time to reach the maximum drug concentration (t max ) were treated as missing / omitted. The mean concentration value BLQ was reported as BLQ in the table and not plotted in the figure if the time to the last observed concentration (t last ) had elapsed.

[0230] Population PK / PD Modeling: Population PK analysis using data from both Part 1 and Part 2 was performed with non-linear mixed effects modeling (NONMEM; version 7.4.1). Covariates including demographics (gender, age, weight, and race), ADA status, baseline complement factor C4, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were screened graphically. The selected covariates (ADA status, gender, age, weight, and race) were statistically evaluated using stepwise forward selection / variable reduction steps. The relationship between SAR445088 exposure and PD response was investigated. Covariates (age, weight, gender, race, baseline CP, and CH50) were statistically evaluated using stepwise forward selection / variable reduction. Covariates contributing at least a 6.63 unit change in the minimum value of the objective function (MVOF) (α = 0.01, 1 degree of freedom) were considered statistically significant during stepwise forward selection. Covariates contributing to the most significant change in MVOF (lowest p-value) were included in the new base covariate model. The new model was also evaluated for a reduction in between-subject variability (IIV) of PK parameters. Highly correlated covariates were not included in a single covariate parameter submodel. This process was repeated until no further covariates caused a significant change in MVOF. The resulting model was considered the full multivariate model. The adequacy of the structural and statistical models was evaluated throughout and improved as necessary.

[0231] In the variable reduction method for covariates, each covariate was removed separately from the parameter equation. A covariate was considered significant if it contributed to at least a 10.83 change in the MVOF value (α = 0.001, 1 degree of freedom) when removed from the model. The least significant covariate (highest p-value > 0.001) was removed from the model, and this reduced model was used as the new base multivariate model. The variable reduction procedure was repeated until all remaining covariates were statistically significant (p < 0.001).

[0232] Statistical Analysis Safety: Safety analyses (including AE, laboratory parameters, vital signs, and ECG) were based on a review of individual values and descriptive statistics. The duration of treatment-emergent adverse events (TEAEs) was defined as the period from the first dose of SAR445088 to the end of the study visit (inclusive). AEs were coded according to the Medical Dictionary for Regulatory Activities version 23.0, and severity was evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0. The number (%) of participants experiencing TEAEs was summarized by dose level group. Potentially clinically significant abnormalities in laboratory results, vital signs, and ECG were flagged and summarized by dose level group using frequency tables.

[0233] The SLE panel test was evaluated by summarizing the number (%) of participants with negative, positive, or borderline data for each dose level group, parameter, and visit. The number of participants experiencing local injection site reactions (e.g., pain, tenderness, erythema, swelling / sclerosis, or pruritus) was summarized by dose level group and grade (mild / moderate, severe, and very severe). The immunogenicity of SAR445088 was evaluated by summarizing the number and percentage of participants with ADA-positive or -negative status for each dose level group and visit. If ADA was positive, the absolute ADA concentration was summarized with descriptive statistics by dose level and visit.

[0234] Pharmacokinetics: SAR445088 PK parameters were summarized by dose level using descriptive statistics. Dose proportionality was evaluated using a power model for the maximum drug concentration in plasma (C max ), area under the curve from dose to the time of the last measured concentration (AUC last ), or area under the curve from 0 to 168 hours (AUC 0-168 ), and for AUC for each route (IV and SC). Accumulation was evaluated using a linear model of the logarithmically transformed accumulation rate. Logarithmically transformed C max and AUC0-168 The dispersion component of 0-168 was estimated using a linear model.

[0235] Pharmacodynamics: Percent CP activity, percent AP activity, CH50, and C4 were analyzed in all participants. Descriptive statistics were provided by dose level and measurement time.

[0236] Results Participant demographics and treatment Overall, 93 healthy participants were enrolled in Part 1 and Part 2. In Part 1, a total of 65 participants were enrolled. A single dose of SAR445088 or its corresponding placebo was administered IV to a total of 45 participants, including 33 participants who received SAR445088 and 12 participants who received placebo. A single dose of SAR445088 or its corresponding placebo was administered SC to a total of 20 participants, including 15 participants who received SAR445088 and 5 participants who received placebo. In the Japanese cohort, 3 participants received SC administration of SAR445088. Except for the non-Japanese cohort at 50 mg / kg IV and the Japanese cohort at 300 mg SC, all cohorts completed enrollment as planned with 8 participants (6 SAR445088 and 2 placebo). Enrollment in these two cohorts ended early due to difficulties in recruitment during the COVID-19 pandemic. One patient in the Japanese at 300 mg SC discontinued the study for reasons unrelated to the study.

[0237] In Part 2, a total of 28 participants were registered, randomized, and received multiple administrations of SAR445088. Twenty-two participants received SAR445088 and six participants received placebo. One placebo-treated subject withdrew from the study due to a TEAE (decrease in neutrophil count) and discontinued the study treatment. This subject was not replaced. Enrollment into the cohort receiving 600 mg SC once daily for 3 days ended early due to recruitment difficulties caused by the COVID-19 pandemic. All participants enrolled in Parts 1 and 2 were included in the safety, PK, and PD analyses. The patient disposition flowchart is shown in Figure 1. Demographic and baseline characteristics are shown in Tables 2–4.

[0238]

Table 2

[0239]

Table 3

[0240]

Table 4

[0241] Safety and Tolerability The safety population included 93 randomized, healthy adult participants who received at least one dose of SAR445088 or the corresponding placebo. During the study, no deaths, serious TEAEs, or serious adverse events (SAEs) that occurred during treatment were reported.

[0242] Overall, no concerning trends were observed in vital signs, ECG, or laboratory values. No serious infections or meningococcal infections occurred.

[0243] Pharmacokinetics The mean (±SD) PK parameters after IV and SC administration, and the corresponding plasma concentration-time profiles for Parts 1 and 2 are shown in Table 5 and Figure 2, respectively.

[0244]

Table 5

[0245] The bioavailability range of SAR445088 after SC administration was 67.5% - 92.0%. After single - dose IV or SC administration of SAR445088, exposure increased proportionally with dose over the entire range of 2 - 50 mg / kg IV or 600 - 1200 mg SC. After single - dose SC administration, the PK profile of SAR445088 was characterized by slow absorption (3.95 - 21.1 days). Long half - lives (cohort mean: 8 - 15 weeks) were observed after IV or SC administration.

[0246] Treatment - related ADA was observed in 2 participants in Part 1 (1 subject each after 2 mg / kg IV and 600 mg SC) and 2 participants in Part 2 (300 mg SC group), and there was no apparent effect on SAR445088 exposure.

[0247] Pharmacodynamics Percent CP activity: Dose - dependent inhibition of percent CP activity, analyzed as change from pre - dose levels, was observed after single or multiple doses of SAR445088 (Figures 3A - 3C). In Part 1, the maximum inhibition of percent CP activity from baseline was greater than 90% after single - dose 30 or 50 mg / kg IV on Day 1 and 55% after single - dose 1200 mg SC on Day 7. The degree and duration of inhibition of percent CP activity after single - dose IV or SC administration appeared to be dose - dependent. The maximum inhibition of percent CP activity greater than 90% persisted for approximately 4 weeks after administration of 50 mg / kg IV. In Part 2, the maximum inhibition of percent CP activity from baseline was 82% on Day 35 after weekly 600 mg SC administration in Week 4, and the inhibition of percent CP activity persisted throughout the study period. After three daily 600 mg SC administrations, the maximum inhibition of percent CP activity from baseline was 70.5% on Day 15 and then decreased.

[0248] CH50 inhibition: Dose-dependent inhibition of CH50 was observed after single or multiple administrations of SAR445088 (Figure 3D - 3F). In Part 1, a sustained decrease in CH50 (to ≤10 IU / mL) was observed within 1 hour after a 16 mg / kg IV administration, and this level was maintained until week 3. Administration of 30 mg / kg IV (for >3 weeks) or 50 mg / kg IV (for >8 weeks) resulted in a more sustained decrease in CH50 to <10 IU / mL. After a single 1200 mg SC administration, a decrease in CH50 (≤10 U / mL) was observed on day 5, which persisted until day 15. In Part 2, a decrease in CH50 (≤10 U / mL) was observed in the cohort receiving 600 mg SC weekly on day 22 and was maintained at this level until day 84. Daily administration of 600 mg SC for 3 days decreased CH50 to ≤10 IU / mL on day 8, which persisted until day 22. Percent AP activity did not change after single IV or SC administration and was similar to baseline levels throughout the study period for all participants. C4 is the first complement component in CP cleaved by activated C1s. Total C4 levels did not change after single or multiple administrations and were similar to baseline levels throughout the study period in all study participants. Without wishing to be bound by theory, this is probably due to the fact that the study was conducted in healthy participants with only low levels of C1s activation.

[0249] Population PK / PD Modeling Population PK Modeling: A total of 70 participants (administered SAR445088) and 1244 concentration records were used for model development. The population PK of SAR445088 was characterized by a two-compartment model with first-order absorption and linear elimination. The typical clearance was 2.12 mL / hour. The total volume of distribution (V d)(5.45 L) was consistent with the plasma volume, and drug distribution was limited to the blood circulation. The model-estimated bioavailability after SC administration was 75.4%. The population PK parameters were estimated with good precision with a relative standard error (RSE) of less than 30%. The magnitude of the estimated IIV was moderate (36.6% CV to 75.0% CV). The results of the visual predictive check (VPC) showed that most of the observed concentrations were within the prediction range (5th to 95th percentile). Among the covariates tested, body weight with respect to the volume of the peripheral compartment (V2) was retained as a statistically significant covariate. Peripheral V d increased 2.3-fold as body weight increased from 50.4 kg (minimum) to 100.8 kg (maximum) (Figure 4A).

[0250] Exposure-response relationship: A total of 93 participants (administered SAR443088 or placebo) and 1496 records of CP and 963 records of CH50 were used for the development of the PK / PD model. The base CPPK / PD model was a direct response model with a non-linear source of variation. Baseline CP activity was identified as the main cause of the SAR445088 CP population pharmacokinetic-pharmacodynamic (PopPK / PD) variation. The observed baseline CP range was 66.2% to 186%, and the modeled base CP range was 75.3% to 139%. The VPC showed that most of the observed concentrations were within the prediction range (5th to 95th percentile). For percent CP, the typical IC 50 was 96.4 μg / mL, and the typical IC 90 was 458 μg / mL. The base CH50 PK / PD model was a direct response model with a non-linear PD effect (Figures 4B - 4E). No covariates were identified for the CH50 population PK / PD model that met the predefined criteria for inclusion. The results of the VPC showed that most of the observed concentrations were within the prediction range (5th to 95th percentile). For CH50, the typical IC 50 was 16.6 μg / mL, and the typical IC 90 was 57.0 μg / mL.

[0251] Using the final CP model, the concentration-time profile of SAR445088 was simulated for a patient population (n = 200) with a body weight of 70 kg for the proposed treatment regimen (50 mg / kg IV loading and weekly 600 mg SC maintenance). The proposed treatment regimen achieved inhibition of CP (based on the PK / PD relationship of the Wieslab CP assay) after the first dose and maintained this inhibition throughout the treatment period.

[0252] Discussion In this FIH trial in healthy participants, single or multiple doses of up to 50 mg / kg IV of SAR445088 were well tolerated and no safety concerns were noted. All reported TEAEs were of mild or moderate severity. No deaths, serious AEs, serious infections, infections due to encapsulated bacteria, or meningitis were reported in this trial. The risk of infection due to encapsulated bacteria as a result of SAR445088 administration may be lower compared to other complement inhibitors because SAR445088 leaves the alternative and lectin pathways of complement intact. Vaccination against encapsulated bacteria such as Neisseria meningitidis was required in this trial to reduce this risk. Based on data from participants with congenital CP deficiency, the theoretical risk of inhibition of C1s is the development of SLE. No AEs related to the development of SLE were reported in this trial.

[0253] The PK of SAR445088 in healthy participants is notable for a long elimination half-life after IV or SC administration, which is due in part to the methionine-leucine (M428L) and asparagine-serine (N434S) mutations, which increase the binding affinity for the neonatal Fc receptor (FcRn) at pH 6.0. In addition, SAR445088 binds only to activated C1s. Target-mediated drug disposition (TMDD) was not observed at the tested dose levels. Good bioavailability after SC administration was also observed, which offers the possibility of self-administration at home in chronic diseases that require maintenance therapy. An approximately dose-proportional increase in SAR44508 exposure was observed over the evaluated dose range.

[0254] The incidence of treatment-induced ADA was low and there was no apparent impact on SAR445088 exposure, PK parameters or the safety profile of SAR445088.

[0255] Complement inhibition was measured using two different assays, the Wieslab CP and CH50 hemolysis assays. In each assay, dose-dependent inhibition of CP was observed that reached levels observed among individuals with congenital or acquired classical complement deficiencies. Also, when comparing the Wieslab CP and CH50 hemolysis assays, an approximately 8-fold difference in IC 50 values was observed, and higher drug exposure was required in the CH50 hemolysis assay than in the Wieslab CP assay to achieve the same level of CP inhibition. This may be due to differences in sample assay dilution and readout in the CH50 and Wieslab CP assays. Notably, a similar discrepancy between percent CP and CH50 also occurred in in vitro tests using SAR445088 in patient blood samples.

[0256] Conclusion In this FIH study in healthy adults, SAR445088 was well tolerated and no severe or serious adverse events occurred. SAR445088 demonstrated dose-dependent inhibition of classical CP in healthy participants after single IV or SC and multiple escalating weekly or daily SC doses.

[0257] Example 2. Multicenter, Phase 1b, Open-Label, Non-Randomized, Single-Dose Trial to Evaluate the Safety, Tolerability, and Activity of SAR445088 in Adults with Cold Agglutinin Disease Theory The objective of this Phase 1b trial was to determine the safety, tolerability, activity, and PK of a single-dose IV administration of SAR445088 in an adult population of patients with cold agglutinin disease (CAD). This trial aimed to detect biomarker evidence of improvement in hemolysis by testing the effect of SAR445088 in CAD and to support the proof of concept of SAR445088.

[0258] Method This was a multicenter, Phase 1b, open-label, non-randomized trial to evaluate the safety and tolerability of a single intravenous (IV) dose of SAR445088 in adult participants with cold agglutinin disease (CAD).

[0259] This trial was designed to evaluate the effect of SAR445088 on complement classical pathway-mediated hemolysis in CAD and to generate data to determine doses for future trials. The trial design included up to three single-dose IV cohorts. The trial started dosing at 30 mg / kg IV in Cohort 1a and made in-trial decisions regarding selection of the next cohort's dose and / or expansion within a cohort based on clinical responses (total bilirubin and hemoglobin) and variability in responses among participants. Following Cohort 1a, a high-dose cohort (Cohort 1b) or a low-dose cohort (Cohort 1c) could have been enrolled. Cohort 1b was not enrolled, but Cohort 1c was enrolled at a dose of 15 mg / kg IV.

[0260] Number of Participants Plan: Approximately 6 participants were to be dosed in any IV cohort. Treatment: Twelve adult participants were treated with a single IV dose of SAR445088. Six participants were dosed with 30 mg / kg IV and six participants were dosed with 15 mg / kg IV. All 12 treated participants were included in all analysis populations (safety, pharmacodynamics, pharmacokinetics, ADA, BA, PK / PD, and PK / BA).

[0261] Inclusion and Exclusion Diagnoses and Main Criteria: Male and female participants 18 years of age and older with CAD and a hemoglobin level of 11 mg / dL or less at screening. i) Have previously received vaccination against capsular organisms ii) Have not received systemic corticosteroids (more than 10 mg / day prednisone or equivalent) within 3 months before screening, systemic immunosuppressive agents, systemic cytotoxic agents, specific complement system inhibitors other than SAR445088, or anti-CD20 therapy. iii) Have not received the administration of any biologic agent (antibody or its derivative) within 4 months before screening.

[0262] Study Intervention Period The total study period for each participant was approximately 23 weeks: ● Screening: Up to 56 days, minimum 14 days (-56 days to -1 day). ● Treatment: 1 day (Day 1); and ● Follow-up and End of Study: 105 days after SAR445088 administration (Follow-up visits on Days 2 to 71; End-of-study visit on Day 106). The study was considered completed for each participant when they had completed all of the scheduled study procedures.

[0263] Statistical Methods Safety: Safety analyses (AEs, laboratory parameters, vital signs, and ECGs) were based on a review of individual values and descriptive statistics, focusing on the TEAE period (inclusive of both ends) defined as the time from the first IMP administration to the end of the study visit. All safety analyses were performed using the safety population by dose-level cohort.

[0264] All AEs were coded according to the Medical Dictionary for Regulatory Activities (MedDRA version 24.1). The severity was evaluated according to NCI-CTCAE v5.0. The number (%) of participants experiencing TEAE was tabulated by dose-level cohort. Potentially Clinically Significant Abnormalities (PCSA) in clinical laboratory results, vital signs, and ECG were flagged and tabulated by dose-level cohort using frequency tables. The SLE panel tests were evaluated by tabulating the number (%) of participants with negative, positive, or borderline data for each dose-level cohort, parameter, and visit. Quantitative SLE parameters were summarized using descriptive statistics (N, mean, SD, SEM, median, minimum, and maximum) and provided by dose-level cohort and time of measurement. The number of participants experiencing local injection site reactions (pain, tenderness, erythema, swelling / sclerosis, or pruritus) was tabulated by dose-level cohort and grade (mild / moderate, severe, and very severe).

[0265] Anti-SAR445088 antibody (ADA): Anti-SAR445088 antibody (anti-drug antibody, ADA): The immunogenicity of SAR445088 was evaluated by assessing the ADA positive or negative status of participants using the ADA population and tabulating by dose-level cohort and visit. In addition, when the ADA status was confirmed, the absolute ADA concentration was summarized with descriptive statistics by dose-level cohort and visit.

[0266] Pharmacokinetics (PK): The SAR445088 concentration calculated in plasma was tabulated by dose-level cohort using descriptive statistics. Additionally, plots of raw data (mean + / - SD) were provided as one curve per dose-level cohort. A population PK model developed in healthy subjects was evaluated in CAD patients by statistically evaluating the model predictions and observed SAR445088 concentrations for each participant.

[0267] Pharmacodynamics (PD): All PD analyses were performed by dose-level cohort using the PD population. The quantitative parameter percent CP activity, percent AP activity, CH50, and total C4 were analyzed as raw data, change from baseline, and percent normalized to baseline for all participants included in the PD population. CP inhibition rate was analyzed as raw data. Descriptive statistics for raw data, change from baseline, and percent normalized to baseline for percent CP activity, CH50, and total C4 were provided by dose-level cohort and time of measurement. Time profile plots (mean ± standard error of the mean [SEM]) and change from baseline for each dose-level cohort were provided for all PD parameters (percent CP activity, percent CP inhibition, CH50, and total C4).

[0268] Biomarker activity (BA) Hematological BA was analyzed as raw data and change from baseline in all participants included in the BA population. Time profile plots (mean ± standard deviation [SD]) for each dose-level cohort were provided for all BA parameters and change from baseline.

[0269] PK / PD and PK / BA The relationships between PD and BA variables and SAR445088 plasma concentration were explored graphically using the PK / PD population and the PK / BA population. The mean (±SEM) change from baseline in PD and BA data and plots of mean SAR445088 plasma concentration vs. time (time post-dose) were overlaid on the same plot. Scatter plots of PKSAR445088 concentration and change from baseline vs. PD raw data were provided over time.

[0270] Summary of Results and Conclusions: A total of 12 participants received a single dose of SAR445088 by IV administration.

[0271] Demographic and Other Baseline Characteristics: The age range of the study participants was 54 - 80 years old (mean 67.4; median 69.0). The study included 1 male and 11 female participants.

[0272] Exposure: This study began with 3 participants in Cohort 1a receiving a single dose of 30 mg / kg IV. After dosing, 2 of the 3 participants were found to have bilirubin within the normal range at baseline, despite having bilirubin above the ULN during screening. Therefore, it was decided to enroll an additional 3 participants at a dose of 30 mg / kg. Normalization of bilirubin levels by Day 8 was seen in 4 participants in Cohort 1a who had bilirubin levels above the ULN at baseline. Therefore, it was decided to proceed to Cohort 1c at a dose of 15 mg / kg.

[0273] Overall, 6 participants received a single dose of 30 mg / kg IV of SAR445088 and 6 participants received a single dose of 15 mg / kg IV of SAR445088.

[0274] Safety results: There were no SAEs, TEAEs leading to death, or TEAEs leading to permanent study discontinuation that occurred during treatment. No participants experienced severe infection, meningococcal infection, allergy and / or hypersensitivity reaction, or thromboembolic events.

[0275] Overall, SAR445088 was generally well tolerated. No new safety concerns were identified.

[0276] Pharmacodynamic results: After a single dose of SAR445088 at 30 mg / kg IV, the mean percent CP activity decreased from 49.70% of baseline to less than 10% at D1 1H and subsequently the CP activity increased gradually. The mean CH50 value decreased from 21.7 IU / mL at baseline to less than 10 IU / mL at D1 1H. At the EOS visit, the mean CH50 value remained less than 10 IU / mL. After a single dose of SAR445088 at 15 mg / kg IV, the mean percent CP activity decreased from 56.09% of baseline to less than 10.23% at D1 1H and subsequently the CP activity increased gradually. The mean CH50 value decreased from 25.7 IU / mL at baseline to less than 10 IU / mL at D1 1H. At the EOS visit, the mean CH50 value was 13.6 IU / mL. A decrease in AP activity was not observed during the study period.

[0277] The effect of SAR445088 on clinical biomarkers of hemolysis was evaluated at each time point using mean total bilirubin (a marker of red blood cell destruction) and mean hemoglobin. After a single dose of 30 mg / kg, mean bilirubin decreased from 21.18 μmol / L at baseline (upper limit of normal value, 17.1 μmol / L) to a trough value of 7.35 μmol / L on day 29 and 9.41 μmol / L at the EOS visit. After a single dose of 15 mg / kg, mean bilirubin decreased from 35.91 μmol / L at baseline to a trough value of 11.97 μmol / L on day 71 and the value at the EOS visit was 20.52 μmol / L (Figure 5).

[0278] After a single dose of 30 mg / kg, hemoglobin increased from a mean of 97.3 g / L at baseline to a peak of 121.7 g / L on day 43 and the value at the EOS visit was 121.3 g / L. After a single dose of 15 mg / kg, hemoglobin increased from 85.9 g / L at baseline to a peak of 121.5 g / L on day 57 and the value at the EOS visit was 119.5 g / L (Figure 6). In the 15 mg / kg group, two participants received a concentrated red blood cell transfusion on the day of SAR445088 administration. Analysis of the increase in hemoglobin from baseline in this group may be affected by these transfusion events.

[0279] Pharmacokinetic results: The SAR445088 concentration was generally within the 90% prediction interval based on the PopPK model developed in healthy participants, and the PK in CAD participants was shown to be similar to that in healthy participants (Figure 7).

[0280] Other results: There were no participants with treatment-induced ADA, treatment-facilitated ADA, or ADA developed during treatment. There were no participants with indeterminate ADA.

[0281] Conclusion: Single-dose administration of SAR445088 had an acceptable safety and tolerability profile in adult participants with CAD. A sustained decrease in CH50 was observed after single doses of 30 mg / kg IV and 15 mg / kg IV during the 15-week follow-up. The observed decrease in CH50 values corresponded to a decrease in total bilirubin and an increase in hemoglobin during the 15-week follow-up period. Overall, these findings demonstrate that single IV administration of 30 or 15 mg / kg of SAR445088 results in classical complement inhibition, control of hemolysis, and improvement of anemia in adult patients with CAD.

[0282] Example 3. Selection of SAR445088 dosing regimen for Phase 2 / 3 trial The primary objective of this study was to simulate the dosing regimen for a Phase 2 / 3 trial in patients with cold agglutinin disease (CAD) and chronic inflammatory demyelinating polyneuropathy (CIDP).

[0283] Methods: Software SAR445088 concentration-versus-time data were simulated using NONMEM software version 7.4.1 (ICON, Development Solutions, Elliot City, MD, USA).

[0284] Using R, the simulation dataset, graph analysis, descriptive statistics, and NONMEM output were evaluated (R Core Team. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing. Vienna, Austria, 2019).

[0285] Population pharmacokinetics / pharmacodynamics model PopPK and PopPK / PD models in healthy subjects Using data from single and multiple ascending dose trials in healthy adult participants (Example 1), population pharmacokinetics (PopPK) models and population pharmacokinetics / dynamics (PopPK / PD) models for SAR445088 were developed. In these trials, intravenous (IV) doses of 2 - 50 mg / kg and subcutaneous (SC) doses of 300 - 600 mg were investigated as single or multiple doses.

[0286] The pharmacokinetics (PK) of SAR445088 in healthy subjects was appropriately described by a two - compartment model with linear elimination with first - order absorption after subcutaneous (SC) administration. The typical clearance (CL) was 2.21 mL / hour. The total distribution volume (V) was consistent with the plasma volume, indicating that drug distribution was limited to the blood circulation. The weight dependence of the peripheral distribution volume (V p ) was the main cause of SAR445088 PK variability. V p increased 2.3 - fold as body weight increased from 50.4 kg to 100.8 kg (range observed in healthy subject trials). Additionally, all other covariates including age, gender, race, and anti - drug antibody (ADA) status were evaluated, but no statistically significant effect on SAR445088 PK was observed.

[0287] The popPK model suggested that SAR445088 was more distributed in the organs and tissues of individuals with higher body weights. High inter-compartment clearance (Q = 14 mL / h) and low CL indicated that SAR445088 was present in the central volume of distribution (V c ) most of the time. Therefore, body weights beyond the test range were expected to have a negligible impact on SAR445088 plasma concentrations.

[0288] A popPK / PD model was developed for complement pathway activity measured by the Wieslab classical pathway (CP) and 50% hemolytic component (CH50) as pharmacodynamic (PD) markers. Discrepancies in PK / PD for CP and CH50 of SAR445088 were observed: the IC 90 for CP was 458 μg / mL, while for CH50 it was 57.0 μg / mL. As a conservative approach, the CP PK / PD model was used to propose dosing regimens for the Phase 2 CAD and CIDP trials.

[0289] Simulations for dose selection in Phase 2 / 3 trials The popPK and popPK / PD models were used for simulations of different dosing regimens (once a week, qw; once every two weeks, q2w; once a month, qm; once every 12 weeks, q12w) with the goal of achieving less than 10% CP (i.e., >90% inhibition) or less than 10 U / mL CH50, regardless of the presence or absence of an IV or SC loading dose.

[0290] Selection of dosing regimens for Phase 2 CAD and CIDP trials Based on the above-described CP popPK / PD model, single IV doses of 15 and 30 mg / kg were selected for the proof-of-concept trial in CAD patients (Example 2). Using these models, for the Phase 2 CIDP trial, a loading dose of 50 mg / kg IV followed by 600 mg SC weekly starting on Day 8 was selected.

[0291] Regimens based on fixed doses per body weight PK simulations based on body weight were performed using the pppPK model of SAR445088. As a conservative approach to evaluate the impact of body weight on SAR445088 exposure, the PK parameters CL and V were scaled allometrically based on body weight. The exponent used for CL was 0.85 and the exponent used for V was 1. The equations for CL and V were as follows:

Number

Number

[0292] The body weight distribution of 35 - 200 kg was classified into bins according to Table 6 to facilitate comparison.

[0293]

Table 6

[0294] From the body weight distribution, patients (n = 1000) were randomly selected by replacement using R script. For each patient (n = 1000), the SAR445088 exposure profile was simulated until steady state. The PK parameter area under the curve (AUC ss ) and the pre - dose concentration (C トラフ ) at steady state were estimated.

[0295] Body weight distribution and simulation Using the PK / PD model of CH50, the following regimens adjusted to a 70 - kg individual were evaluated for the CAD and CIDP patient populations: Fixed - dose regimen: 3.5 g IV q12w and an additional 3.5 g IV dose on day 29 Dose regimen based on body weight: 50 mg / kg q12w and an additional 50 mg / kg IV dose on day 29.

[0296] The body weight distribution data were obtained from the following studies: 1) CAD: Cadenza (BIVV009-03) and Cardenal (BIVV009-04) trials; n = 66, median = 65.6 + / - 13.5 kg. 2) CIDP: CIDP patient population from the US Centers for Disease Control database (US Centers for Disease Control database. US CIDP patient weights. February 2022); n = 100, median = 83.9 + / - 35.8 kg.

[0297] The population density of the indications was overlapping, and the majority of the patients were in the range of 50 - 90 kg.

[0298] Results and Discussion: Selection of dosing regimens for Phase 2 CAD and CIDP trials CAD Based on the PK / PD model of CP, a single IV dose of 30 mg / kg in CAD patients was predicted to achieve a maximum concentration (C max ) of approximately 660 μg / mL with less than 10% CP in 60% of the patients (Figure 8).

[0299] CIDP Following a loading dose of 50 mg / kg IV and administering 600 mg SC qw on Day 8, the pre-dose concentration at steady state (C トラフ ) was predicted to be approximately 1210 μg / mL with less than 10% CP value in the majority of the patients (50%) throughout the treatment period (Figure 9). The estimated exposure margin based on comparing the AUC of the 26-week non-human primate (NHP) study's no-observed-adverse-effect level (NOAEL) (AUC0-12wks = 8,388,000 μg×h / mL) was greater than 2. ss

[0300] A loading dose was required to rapidly achieve 90% CP inhibition. For example, a 1200 mg SC dose administered every 2 weeks (q2w) achieved 90% CP inhibition approximately 12 weeks from the start of treatment with C トラフ at 1145 μg / mL.

[0301] Alternative regimen Low dose The doses proposed for the second phase of CIDP were based on CP PK / PD as a conservative approach. A regimen based on CH50 PK / PD, which requires a lower maintenance dose, was proposed for SC and IV.

[0302] SC. The low maintenance dose regimen by the proposed SC administration was 50 mg / kg IV on day 1 and 300 mg SC qw on day 8. Based on the CH50 popPK / PD model, this dosing schedule achieved a rapid SAR445088 level that reduced the CH50 value to less than 10 U / mL, and during the treatment period, C トラフ was sustained at approximately 600 μg / mL.

[0303] IV. The low maintenance dose regimen by the proposed IV administration was 50 mg / kg IV q8w on day 1. Based on the CH50 popPK / PD model, this dosing schedule achieved a rapid SAR445088 level that reduced the CH50 to less than 10 U / mL, and during the treatment period, C トラフ was sustained at approximately 800 μg / mL.

[0304] Regimen based on a fixed dose per body weight A body weight-based regimen that administered a 50 mg / kg IV dose every 12 weeks (q12w) and an additional 50 mg / kg IV dose on day 29 was compared with an equivalent fixed dose for a 70-kg individual to support the dose selection in the CAD phase 3 trial. Figure 10 shows a simulation that administered 3.5 g IV every 12 weeks and an additional 3.5 g IV on day 29. At steady state, it was predicted that the SAR445088 level would be less than 300 μg / mL in 12% of patients, but would exceed 100 μg / mL in 100% of patients. The comparison of C トラフ for the proposed regimens of 3.5 g and 50 mg / kg トラフ showed that C was equivalent between the two approaches (Table 7).

[0305]

Table 7

[0306] Steady-state area under the curve (AUC ss ) is shown in Figure 11 and summarized in Table 8. In the fixed-dose approach, AUC ss tended to decrease from low body weight (Bin A) to high body weight (Bin H), and this decrease was about 2.8-fold. In the dose regimen based on body weight, AUC ss tended to increase from low body weight (Bin A) to high body weight (Bin H), and this increase was about 1.2-fold.

[0307]

Table 8

[0308] For medium body weight bins 65 - 105 kg, the exposure between the 3.5 g fixed and 50 mg / kg dosing approaches was equivalent, and most patients were as expected. The greatest differences were observed at extremely low (Bin A) and high (Bin H) body weights, and the fixed-to-weight-based AUC ss ratio was 1.54 for Bin A and 0.46 for Bin H.

[0309] The simulated minimum plasma drug concentration at steady state (C トラフ ) is shown in Figure 12 and summarized in Table 9. In the 3.5 g fixed-dose approach, C トラフ tended to decrease from low body weight (Bin A) to high body weight (Bin H), and this decrease was about 2.3-fold. In the 50 mg / kg dosing approach, C トラフ tended to increase from low body weight (Bin A) to high body weight (Bin H), and this increase was about 1.5-fold. Similar to AUC ss , the intermediate bins (C - F) were equivalent between the fixed-dose approach and the weight-based dosing approach. The greatest differences were observed at extremely low (Bin A) and high (Bin H) body weights, and the fixed-to-weight-based C トラフ ratio was 1.56 for Bin A and 0.46 for Bin H.

[0310]

Table 9

[0311] Steady-state exposure (AUC ss ) was compared to the NOAEL established in the 26-week NHP toxicity study (Table 10). All weight bins had an exposure margin greater than 3.

[0312] In the study of healthy subjects (Example 1), the highest overall exposure was from the 50 mg / kg IV single-dose cohort: C max was 1180 μg / mL and AUC 0-∞ was 1390000 μg×h / mL. No serious adverse events (SAEs) were observed in these subjects. The proposed steady-dose regimen exposure is thought to be 1.73 to 0.62 times the exposure observed in healthy subjects for 35 to 200 kg.

[0313]

Table 10

[0314] C トラフ level analysis for fixed doses is shown in Table 11 and for dose approaches based on body weight is shown in Table 12.

[0315]

Table 11

[0316]

Table 12

[0317] At steady state, 92% of patients had a C トラフwere predicted to have. In the fixed-dose approach, 84 out of 982 patients were below 300 μg / mL and 18 out of 982 were below 200 μg / mL. This was comparable to the weight-based dosing approach, where 82 out of 982 patients were below 300 μg / mL and 12 out of 982 were below 200 μg / mL. Overall, 100% of the patients were predicted to exceed 100 μg / mL (IC 90 more than twice that of).

[0318] Conclusion: 1) Bayesian analysis showed that CAD patients had a PK profile similar to that of healthy participants. 2) The decrease in CH50 values upon SAR445088 exposure in CAD patients correlated with improved clinical markers, bilirubin and hemoglobin, and CH50 was confirmed as a relevant PD marker for SAR445088. 3) The dosing regimens selected for the Phase 2 trial were predicted to achieve < 10% CP (i.e., > 90% inhibition) or CH50 < 10 IU / mL in the majority of patients over the entire treatment period. The predicted exposure margins for these regimens were greater than 2 compared to the 26-week NHP NOAEL. 4) The fixed-dose regimen appeared to generate similar C トラフ values across the 35 - 200 kg body weight range as the weight-based regimen, which was considered to remain above 100 μg / mL in 100% of the patients. The predicted exposure margin of the 35 - 200 kg fixed-dose regimen was greater than 3 compared to the 26-week NHP NOAEL.

[0319] Example 4. A Phase 2, multi-site, open-label, non-randomized, proof-of-concept trial to evaluate the efficacy, safety, and tolerability of SAR445088 in adults with CIDP As described in Example 1 above, at least 90% maximal CP inhibition was obtained by single-dose SAR445088b IV administration at 30 mg / kg or 50 mg / kg. The 90% cut-off for CP inhibition was derived from previous studies using first-generation C1s mAbs used in cold agglutinin disease (CAD), and it was found that 90% CP inhibition is a predictor of therapeutic effect (blocking of hemolytic activity in the blood compartment) (Jager et al. Blood. 2019 Feb 28;133(9):893-901. doi:10.1182 / blood-2018-06-856930. Epub 2018 Dec 17). Therefore, such a degree of CP inhibition is expected to lead to a therapeutic benefit (improvement of severe hemolytic anemia in CAD). CAD represents a good model of complement-mediated diseases in the blood compartment. However, the target site of CIDP is in the peripheral nerves, which requires SAR445088 to cross the blood-nerve barrier. To account for the uncertainty of SAR445088's ability to reach sufficient exposure at this target site in CIDP patients, twice the CP IC90 plasma concentration (i.e., 1200 μg / mL) was used as the exposure criterion for phase 2 dose selection.

[0320] The available data from the phase 1 trial support the initiation of a phase 2 trial in CIDP patients using a dose expected to result in at least 90% target inhibition of CP, which is expected to reverse the pathological activation of this pathway. This effect could lead to clinical benefits associated with the resolution of neuroinflammation, remyelination, and prevention of axonal degeneration.

[0321] The objective of this SAR445088 phase 2 trial is to determine the preliminary efficacy, safety, and tolerability of SAR445088 in three CIDP subpopulations, including standard of care (SOC) treatment, SOC-resistant, and SOC-naïve. The results from this phase 2 trial will determine proof of concept (PoC) and inform phase 3 trials.

[0322] This trial is a global, multi-center, Phase 2, open-label, PoC trial evaluating the efficacy, safety, and tolerability of SAR445088 in three subpopulations of patients with CIDP: patients treated with standard of care (SOC) therapy defined as intravenous immunoglobulin (IVIG), subcutaneous immunoglobulin (SCIg), or corticosteroids; patients with SOC-resistant CIDP; and patients with treatment-naive CIDP. The trial consists of two parts: an initial 24-week treatment period (Part A) followed by an optional extension period (Part B) for up to 1 year for the evaluation of long-term safety and tolerability, during which additional treatment is provided. A schematic of the trial is shown in Figure 13.

[0323] In this trial, patients are enrolled from three CIDP subpopulations divided according to their experience with SOC therapy defined as immunoglobulin or corticosteroids: I. Resistant to SOC (SOC-resistant); n = 20 participants: patients defined as having evidence of failure or inappropriate response to SOC before screening, no clinically significant improvement after at least 12 weeks of treatment with SOC, a persistent INCAT score of 2 or more, or unable to receive or continue treatment with immunoglobulin or corticosteroids due to side effects. Patients must not have received immunoglobulin (IVIg or SCIg) within 12 weeks prior to screening. Patients have an INCAT score of 2 - 9 (score 2 is considered to be from the motor disability component of INCAT only). Clinically significant improvement (and worsening) is defined as, respectively, one of the following: a decrease (increase) of 1 point or more in the adjusted INCAT score, an increase (decrease) of 4 points or more in the total I-RODS score, an increase (decrease) of 3 points or more in the total MRC score, an improvement (decrease) of 8 kilopascals or more in the mean grip strength (one hand), or an equivalent improvement (worsening) based on information recorded in the medical record and the judgment of the PI. II. Naïve to SOC (treatment-naïve), n = 20 participants: Patients who have not previously received treatment for CIDP, or patients who have received immunoglobulin (IVIg or SCIg) or corticosteroids but were discontinued for reasons other than lack of response or side effects. Patients must not have received treatment with immunoglobulin (IVIG or SCIG) or corticosteroids for at least 6 months prior to screening. Patients have an INCAT score of 2 - 9 (score 2 is thought to be from the motor disability component of INCAT only). III. Optimally treated with SOC (SOC-treated), n = 50 participants: Participants who have had no more than a 10% change in the frequency or dose of immunoglobulin therapy or corticosteroids within 8 weeks prior to screening and who have continued stable SOC therapy up to the first dose of SAR445088, who have received stable SOC therapy and have documentation of objective and clinically meaningful response evidence within 24 months prior to screening, and evidence of clinically meaningful worsening due to interruption or dose reduction of SOC therapy. Clinically meaningful improvement is defined as above.

[0324] Since CIDP is a rare disease that limits the number of available study participants, this Phase 2 study will not include a control group, but the study design will allow for a sufficient assessment of the safety and efficacy of SAR445088 in this population.

[0325] All participants are administered an IV loading dose of 50 mg / kg of SAR445088 on Day 1, followed by weekly SC injections containing 600 mg of SAR445088. Specifically, for the SOC treatment group: After administration of the IV loading dose on Day 1, patients treated with IVIG, SCIg, or pulse corticosteroids (IV methylprednisolone or oral dexamethasone) will have SAR445088 treatment initiated within 1 week of the last administration of these treatments. Patients receiving daily oral corticosteroids (e.g., prednisone or prednisolone) will taper that treatment over the first 12 weeks of the study. Thus, 600 mg SC of SAR445088 will be administered weekly during the first 12 weeks (overlap period) of the study to augment the effects of SOC therapy.

[0326] Study participants receive a 24-week treatment period (Part A, primary evaluation), followed by an optional extension period (Part B) of up to 52 weeks of additional treatment. The primary endpoints of this proof-of-concept study are as follows: I. SOC-untreated and SOC-resistant: The percentage of participants who respond during the SAR445088 treatment period (up to Week 24). Response is defined as 1 point or more Decrease in the adjusted INCAT disability score. II. SOC treatment: The percentage of participants who relapse after discontinuation of SOC and during the SAR445088 treatment period (up to Week 24). Relapse is defined as an increase of 1 point or more in the adjusted INCAT disability score.

[0327] The secondary objectives of Part A include the safety, tolerability, immunogenicity, and efficacy of SAR445088 (with overlapping SOC therapies in the SOC treatment group). The primary objective of Part B is to evaluate the long-term safety and tolerability of SAR445088 in patients with CIDP. The percentage of participants who have sustained efficacy during the treatment extension period (weeks 24 to 76), i.e., no relapses (SOC treatment) or have a sustained response (SOC resistant and SOC naïve), is defined as an increase in the adjusted INCAT disability score of no more than 2 points. The secondary objectives of Part B are the persistence of efficacy during long-term treatment and long-term immunogenicity.

[0328] Each patient group is analyzed independently according to the time to completion of the trial for each group. Additionally, an independent interim analysis is conducted when 50% of the participants in each group have completed the primary 24-week assessment.

[0329] Use data from the Phase 2 trial to refine the design of the planned Phase 3 trial in patients with CIDP.

[0330] Preliminary results In the ongoing Phase 2 trial PDY16744, two pre-planned interim analyses have been conducted to date. These analyses were performed when 50% of the participants in the standard-of-care (SOC) resistant group and 50% of the participants in the SOC treatment group had completed 24 weeks, which is the time required for the primary endpoint readout. The primary endpoint in the SOC resistant group is the percentage of participants who show a clinically meaningful response during the treatment period from day 1 to week 24. Response is defined as a decrease of 1 point or more in the adjusted INCAT disability score compared to baseline. The primary endpoint in the SOC treatment group is the percentage of participants who have a relapse (clinically meaningful worsening) during the treatment period from day 1 to week 24. Relapse is defined as an increase of 1 point or more in the adjusted INCAT disability score compared to baseline. The INCAT score ranges from 0 (normal) to 10 (maximum disability) and represents the sum of the arm and leg subscales (5 points each). Patients who experienced a relapse (a 1-point increase from baseline in the adjusted INCAT score) during the first 24 weeks of the trial had administration of SAR445088 discontinued. From the results of the two interim analyses conducted to date, the following has been shown: ●Eight out of 12 participants (66.7%) in the SOC resistant group showed a clinically meaningful improvement (response, primary endpoint) after receiving SAR445088, which was maintained through week 24. The SOC resistant group consisted of patients with CIDP who had received multiple treatments. Of the 12 SOC resistant participants included in this analysis, 10 had failed IVIg or had shown an inadequate response, and 7 of those had also tried additional therapies (corticosteroids, immunosuppressive therapy, plasma exchange). The remaining 2 participants had previously received corticosteroids and immunosuppressive therapy. ● Of the 25 participants in the SOC treatment group, 11 (44%) showed a clinically meaningful response after switching from SOC to SAR445088, and this was maintained until week 24. Furthermore, 44% (11 out of 25) of the participants treated with SOC remained stable over 24 weeks (i.e., there was no change in the INCAT disability score). The remaining 12% (3 out of 25) of the participants treated with SOC showed a clinically meaningful deterioration (relapse, primary endpoint) after switching from SOC to SAR445088. Of the 25 SOC-treated participants included in the interim analysis, 18 had received IVIg treatment prior to enrollment, 3 had received both IVIg and corticosteroid therapy, and 4 had received corticosteroid therapy only.

[0331] The observed clinically meaningful response rates in the SOC-resistant and SOC treatment groups indicate that the tested dose regimens of SAR445088 are effective for CIDP. The results observed in these interim analyses also met the predefined criteria for trial success and phase 3 transition determination. Notably, the response rate observed in the SOC treatment group is remarkable because in these patients who were receiving SOC treatment at enrollment, the CIDP disease was expected to be under control, i.e., no improvement was expected.

[0332] The results of additional clinical efficacy are shown in Figures 19 and 20. Figures 19 and 20 show group data corresponding to changes from baseline in the primary clinical outcome measures that assess disability (INCAT disability score, I-RODS) and impairment (grip strength, MRC-SS), respectively, for the SOC-resistant and SOC-treatment groups. The results show internal consistency, with the improvement across the outcome measures following the expected direction and consistent with a positive effect (a consistent decrease in the INCAT disability score over time, combined with a consistent increase in I-RODS, grip strength, and MRC-SS over time). The magnitude of the response observed in the analysis suggests a strong effect as it exceeds the minimally clinically important difference (MCID) thresholds established in the field. In accordance with the consensus, these MCID thresholds are: adjusted INCAT adjusted score: at least 1 point; I-RODS: at least 4 points; grip strength: at least 8 - 14 kPa, and MRC total score (MRCSS): at least 2 - 4 points (2021 EAN / PNS CIDP guidelines, Van den Bergh et al. J Peripher Nerv Syst. 2021;26(3):242 - 268).

[0333] The results for the complement biomarker CH50 are shown in Figure 18. The data suggest that the dose tested, PDY16744, 50 mg / kg IV loading followed by 600 mg SC weekly, results in a potent and sustained inhibition of complement activity in the blood to an extent expected to translate into a beneficial clinical effect (≤10 IU / ml, ≥90% inhibition) based on the extrapolation of the C1s-targeting compound stimalimab in patients with CAD (Jager et al. Blood. 2019 Feb 28;133(9):893 - 901).

[0334] Finally, preliminary data with serum neurofilament light chain (NfL) levels (Figures 21A, 21B) show a trend of decline over time that reflects the effects observed in clinical outcomes. NFL is an objective biomarker of axonal injury that has emerged as a potential biomarker of disease activity in autoimmune neuropathy, particularly CIDP (van Lieverloo et al. J Peripher Nerv Syst. 2019 Jun;24(2):187-194.).

[0335] Overall, the interim data from the ongoing Phase 2 trial PDY16744 are promising, supporting that SAR445088 can address the unmet treatment needs of patients with CIDP. As a potential limitation of the data, since the PDY16744 trial is an open-label, non-controlled trial, it is unclear to what extent the placebo effect plays a role. However, the response rates observed in this trial are clearly superior to the historically reported placebo rates in published trials of CIDP, which range from 11% in trials using response / improvement as the endpoint (meta-analysis Lewis et al. J Peripher Nerv Syst. 2020 Sep;25(3):230-237.). This also holds true for the 12% recurrence rate observed in the SOC treatment group (compared to a past placebo recurrence rate of 43%). Furthermore, the combination of the magnitude of the effect, the directionality across the outcome measures, and the correlation with the objective biomarker effect also supports the interpretation that the results are strong and less likely to be driven by placebo.

[0336] Separate from the two interim analyses, preliminary results of six treatment-naive patients in the Phase 2 trial indicate that the administered regimen was effective, with responses observed in 2 out of 5 completers at the cutoff. Overall, 2 patients who reached 24 weeks responded to treatment, and 1 responding patient discontinued the trial for reasons unrelated to treatment.

[0337] Additional proposed dosing regimens Participants are administered a single IV loading dose of 50 mg / kg on Day 1 and receive SC administration via syringe, or pre-filled syringe, or autoinjector, or large volume drug delivery system. Possible SC doses to be administered include 300 mg qw, 600 mg qw, 600 mg q2w, 1200 mg q2w, 1200 mg q4w, 2400 mg q4w, 3600 mg q12w, or 7200 mg q12w. Participants are regularly administered SC doses via syringe, or pre-filled syringe, or autoinjector, or large volume drug delivery system until the end of treatment.

[0338]

Table 13

[0339] All references, patents, and patent applications disclosed herein are hereby incorporated by reference in their entirety for each subject matter to which each is cited, and may, in some cases, include the entire document.

[0340] As used in this specification and the claims, the indefinite articles "a" and "an" are to be understood to mean "at least one" unless clearly indicated to the contrary.

[0341] Also, it should be understood that, unless clearly indicated to the contrary, in a method comprising a plurality of steps or acts claimed herein, the order of the method steps or acts is not necessarily limited to the order in which the method steps or acts are recited.

[0342] In the claims and the above specification, all transitional phrases such as "comprising", "including", "possessing", "having", "containing", "involving", "holding" and "composed of" should be understood to be open-ended, i.e., including but not limited to these. Only the transitional phrases "consisting of" and "consisting essentially of" are to be closed or semi-closed transitional phrases, respectively, as described in section 2111.03 of the Manual of Patent Examining Procedure of the United States Patent and Trademark Office.

[0343] The terms "about" and "substantially" preceding a numerical value mean ±10% of the recited numerical value.

[0344] When a range of values is provided, each value between the upper and lower ends of the range, including the upper and lower ends of the range, is specifically contemplated and described herein.

Claims

[Claim 1] A method for treating cold agglutinin disease in a subject requiring such treatment, comprising administering to the subject about 3.5 g of a humanized antibody that specifically binds to complement component C1s, wherein the antibody comprises a light chain (LC) complementarity-determining region (CDR) 1 containing the amino acid sequence of SEQ ID NO: 1, an LC CDR 2 containing the amino acid sequence of SEQ ID NO: 2, an LC CDR 3 containing the amino acid sequence of SEQ ID NO: 3, a heavy chain (HC) CDR 1 containing the amino acid sequence of SEQ ID NO: 4, an HC CDR 2 containing the amino acid sequence of SEQ ID NO: 5, and an HC CDR 3 containing the amino acid sequence of SEQ ID NO: 6.

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