Novel antigen binding molecule formats

Abstract

To provide an efficient platform for the generation of binding molecules that might improve affinity, avidity, or antibody function.SOLUTION: Antigen binding molecules (ABMs) comprising Fab domains in non-native configurations, ABM conjugates comprising the ABMs and cytotoxic or cytostatic agents, pharmaceutical compositions containing the ABMs and ABM conjugates, methods of using the ABMs, ABM conjugates and pharmaceutical compositions for treating cancer, nucleic acids encoding the ABMs, cells engineered to express the ABMs, and methods of producing ABMs.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] 1. CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 884,496, filed August 8, 2019, and U.S. Provisional Patent Application No. 63 / 050,483, filed July 10, 2020, the contents of each of which are incorporated herein by reference in their entirety.

[0002] 2. Sequence Listing This application contains a Sequence Listing that has been submitted electronically in ASCII format and is incorporated by reference herein in its entirety. The ASCII copy, created on August 6, 2020, is named RGN-001WO_SL.txt and is 25,358 bytes in size. [Background technology]

[0003] 3.Background technology Most naturally occurring antibody molecules generally contain two so-called light chain polypeptides (light chains) and two so-called heavy chain polypeptides (heavy chains). Each of the heavy and light chain polypeptides contains a variable domain (variable region) (generally the amino terminal portion of the polypeptide chain) that contains a binding region capable of interacting with an antigen. Each of the heavy and light chain polypeptides contains a constant region (generally the carboxyl terminal portion).

[0004] Recombinant monoclonal antibodies, produced by a single clone of a cell or cell line, have emerged over the past two decades as a highly successful class of biological drugs for the treatment of a variety of different diseases. Monoclonal antibodies (mAbs) are an important class of biotherapeutic products, and they have shown outstanding success in treating many life-threatening chronic diseases.

[0005] Increased affinity and / or avidity occurs when the epitope is accessible by the antigen-binding portion of the antibody, e.g., the Fab domain. However, the geometry of traditional antibody formats limits the ability of antibodies to recognize multiple epitopes on a single target molecule, particularly when the target is small in size or when desired epitopes (including those on multiple target molecules) are in relatively close physical proximity, or when physical proximity is desired. Thus, an efficient platform for generating binding molecules that can improve affinity, avidity, or antibody function through alternative antibody-antigen binding geometries would be useful. Summary of the Invention

[0006] 4. Overview The present disclosure provides antigen-binding molecules ("ABMs") containing at least two Fab domains in a non-native configuration. The ABMs comprise at least two polypeptide chains, each comprising one component of an Fc domain and at least two Fab domains. Exemplary ABMs of the present disclosure are shown in Figures 1B, 2B, and 3A-3D.

[0007] Each polypeptide chain, including an Fc domain and any associated polypeptide chains, is referred to herein as a "half antibody." A typical ABM of the present disclosure includes two half antibodies associated through their Fc domains. The associated Fc domains together form an Fc region. In addition to the Fc region, a typical ABM of the present disclosure includes at least one Fab domain in a non-native configuration in each half antibody. At least one or both of the Fab domains in the non-native configuration binds to the target molecule. "Native configuration" or "native immunoglobulin configuration" refers to the configuration of antibody domains in a naturally occurring IgG antibody. In the accompanying schematic diagram, the VH domain is labeled with the number (1), the CH1 domain is labeled with the number (2), the hinge domain is labeled with the number (3), the CH2 domain is labeled with the number (4), the CH3 domain is labeled with the number (5), the VL domain is labeled with the number (6), the CL domain is labeled with the number (7), and the linker that is not the hinge domain is labeled with the number (8). Thus, with reference to the labels in the accompanying figures, the native immunoglobulin structure essentially consists of: a first (heavy chain) polypeptide consisting essentially of, in an N- to C-terminal orientation, a VH domain (1), a CH1 domain (2), a hinge region (3) connected via a disulfide bridge to the hinge region of a second (heavy chain) polypeptide, a CH2 domain (4), and a CH3 domain (5); a second (heavy chain) polypeptide consisting essentially of, in an N- to C-terminal orientation, a VH domain (1), a CH1 domain (2), a hinge region (3) connected via a disulfide bridge to the hinge region of the first (heavy chain) polypeptide, a CH2 domain (4), and a CH3 domain (5); a third (light chain) polypeptide consisting essentially of a VL domain (6) and a CL domain (7) associated in an N- to C-terminal orientation to the first (heavy chain) polypeptide, and A fourth (light chain) polypeptide consisting essentially of a VL domain (6) and a CL domain (7) associated in an N- to C-terminal orientation to a second (heavy chain) polypeptide.

[0008] Reference to "native configuration" or "native immunoglobulin configuration" is not intended to limit the term to wild-type antibody sequences or monospecific antibodies only. Rather, as shown in Figures 1A and 2A, the format can be applied to both monospecific antibodies (Figure 1A) or traditional bispecific antibodies with variant sequences (Figure 2B). The fundamental difference between the monospecific antibody format of Figure 1A and the bispecific antibody format of Figure 2A is not their configuration, but rather their use in Fc heterodimers (e.g., as described in Section 6.2.7.2), in which each Fc region is linked to a different VH domain, allowing binding to a different epitope. For clarity, as used herein, the term "bispecific" refers to binding to any two different epitopes, whether on the same antigen or target molecule or on different antigens or target molecules.

[0009] The ABMs of the present disclosure are particularly useful for binding to small soluble target molecules, e.g., cytokines or chemokines, and find use in antagonizing the activity of target molecules, e.g., by blocking binding of the target molecule to a binding partner such as a receptor. Without being bound by theory, it is believed that the binding formats of the present disclosure allow binding to target molecules with greater affinity and / or avidity than native immunoglobulins comprising the same at least two Fab domains. [Table 1]

[0010] These ABM formats are described in more detail below.

[0011] In a first aspect, the ABM of the present disclosure comprises: In N-to-C-terminal orientation any hinge domain, a first Fc domain, and a first half antibody comprising a first Fab (Fab1) domain comprising a first heavy chain variable region (VH) associated with a first light chain variable region (VL); In N-to-C-terminal orientation any hinge domain, a second Fc domain, and a second half antibody comprising a second Fab domain ("Fab2") comprising a second VH associated with a second VL; The first Fc domain and the second Fc domain are associated with each other to form an Fc region, and the optional hinge domains, if present, may be associated with each other through disulfide bridges.

[0012] Two embodiments of this type of ABM, generally referred to herein as ABM format "A" ("Format A") and sometimes referred to herein as the "Fc-Fab" format, are illustrated in Figures 1B and 2B, and variations thereof shown in Figures 13A, 13B, and 13C. Accordingly, the present disclosure provides: In N-to-C-terminal orientation an optional hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, - an Fc domain comprising a CH2 domain (4) and a CH3 domain (5); an optional hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, a linker (8), and - a first polypeptide comprising a heavy chain component of a Fab1 domain comprising a Fab1 VH domain (1) and a Fab1 CH1 domain (2) associated with a light chain component of a Fab1 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab1 VL domain (6) and a Fab1 CL domain (7); In N-to-C-terminal orientation an optional hinge domain (3) linked via a disulfide bond to the hinge domain in the first polypeptide, - a second Fc domain comprising a CH2 domain (4) and a CH3 domain (5); an optional hinge domain (3) linked via a disulfide bond to the hinge domain in the first polypeptide, a linker (8), and - a second polypeptide comprising a heavy chain component of a Fab2 domain comprising a Fab2 VH domain (1) and a Fab2 CH1 domain (2) associated with a light chain component of a Fab2 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab2 VL domain (6) and a Fab2 CL domain (7); A Format A ABM is provided, as shown in Figures 1B and 2B, in which a first Fc domain and a second Fc domain associate with each other to form an Fc region.

[0013] In the embodiment of Figure 1B, both half antibodies are identical and contain Fc domains that form an Fc homodimer, and the resulting ABM is monospecific. In the embodiment of Figure 2B, the ABM contains an Fc heterodimer, allowing for the use of different Fab1 and Fab2 VH domains and the production of multispecific, e.g., bispecific, molecules. While Figures 1B, 2B, and 13A show embodiments in which the ABM has a hinge region composed of a hinge domain at the N-terminus of the Fc domain, Format A ABMs may not have a hinge region (not shown), a hinge region at the C-terminus of the Fc region (Figure 13C), or hinge regions at the N- and C-termini of the Fc region (Figure 13B). Exemplary hinge domains that can be used at the N- and / or C-termini of the Fc region include the amino acid sequences GGGGSCPPC (SEQ ID NO: 1) and ESKYGPPCPPC (SEQ ID NO: 2), as shown in Figures 13A-13C, although Format A ABMs may have alternative hinge region sequences. Similarly, Figures 13A to 13C show (G4S) n The linker is shown (G4S is disclosed as SEQ ID NO: 3), but other linker sequences can be used.

[0014] While Figures 1B and 2B show embodiments of a Format A ABM containing only two binding domains (Fab1 and Fab2), the ABMs of the present disclosure may contain additional binding domains, such as scFv or Fab domains. However, in certain aspects, Fab1 and Fab2 are the sole binding domains of a Format A ABM.

[0015] In a second aspect, the ABM of the present disclosure comprises: In N-to-C-terminal orientation a first Fab (Fab1) domain comprising a first VH associated with a first VL, a first spacer domain, and a first half antibody comprising a first Fc domain; and In N-to-C-terminal orientation a second Fab (Fab2) domain comprising a second VH associated with a second VL, a second spacer domain, and a second polypeptide comprising a second Fc domain, The first Fc domain and the second Fc domain associate with each other to form an Fc region.

[0016] Without being bound by theory, it is believed that the inclusion of a spacer domain between the Fc and Fab domains allows for greater flexibility between the Fc region and the antigen-binding site of the Fab, and consequently, higher affinity and / or avidity of binding of the ABM to its antigen or target molecule. The terms "antigen" and "target molecule" are used interchangeably herein.

[0017] In certain embodiments, the spacer domain is an extended linker. This ABM format, generally referred to herein as format "B" ("Format B") and sometimes referred to herein as the "reach" format, is illustrated in Figure 3A. Thus, the present disclosure provides: In N-to-C-terminal orientation - a heavy chain component of a Fab1 domain comprising a Fab1 VH domain (1) and a Fab1 CH1 domain (2) associated with a light chain component of a Fab1 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab1 VL domain (6) and a Fab1 CL domain (7); - a linker domain (8) which is an extended linker; a hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, and a first polypeptide comprising a first Fc domain comprising a CH2 domain (4) and a CH3 domain (5); In N-to-C-terminal orientation - a heavy chain component of a Fab2 domain comprising a Fab2 VH domain (1) and a Fab2 CH1 domain (2) associated with a light chain component of a Fab2 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab2 VL domain (6) and a Fab2 CL domain (7); - a linker domain (8) which is an extended linker; a hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, and and a second polypeptide comprising a second Fc domain comprising a CH2 domain (4) and a CH3 domain (5).

[0018] While the embodiment of Format B ABM shown in Figure 3A contains only two binding domains (Fab1 and Fab2), Format B ABMs of the present disclosure may contain additional binding domains, e.g., scFv or Fab domains. However, in certain aspects, Fab1 and Fab2 are the sole binding domains of Format B ABMs of the present disclosure.

[0019] In other embodiments, the spacer domain is a Fab domain. A different variation of this format ABM, referred to herein as format "C" ("Format C"), is illustrated in Figures 3B-3D. A Format C ABM thus comprises a third Fab (Fab3) domain and a fourth Fab (Fab4) domain, configured as follows: In N-to-C-terminal orientation a first Fab (Fab1) domain comprising a first VH associated with a first VL, a third Fab (Fab3) domain comprising a third VH associated with a third VL, and a first half antibody comprising a first Fc domain, and In N-to-C-terminal orientation a second Fab (Fab2) domain comprising a second VH associated with a second VL, a fourth Fab (Fab4) domain comprising a fourth VH associated with a fourth VL, and - a second half antibody comprising a second Fc domain.

[0020] Thus, the present disclosure: In N-to-C-terminal orientation - a heavy chain component of a Fab1 domain comprising a Fab1 VH domain (1) and a Fab1 CH1 domain (2) associated with a light chain component of a Fab1 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab1 VL domain (6) and a Fab1 CL domain (7); - linker domain (8), - a heavy chain component of a Fab3 domain comprising a Fab3 VH domain (1) and a Fab3 CH1 domain (2) associated with a light chain component of a Fab3 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab3 VL domain (6) and a Fab3 CL domain (7); a hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, and a first polypeptide comprising a first Fc domain comprising a CH2 domain (4) and a CH3 domain (5); In N-to-C-terminal orientation - a heavy chain component of a Fab2 domain comprising a Fab2 VH domain (1) and a Fab2 CH1 domain (2) associated with a light chain component of a Fab2 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab2 VL domain (6) and a Fab2 CL domain (7); - linker domain (8), - a heavy chain component of a Fab4 domain comprising a Fab4 VH domain (1) and a Fab4 CH1 domain (2) associated with a light chain component of a Fab4 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab4 VL domain (6) and a Fab4 CL domain (7); a hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, and and a second polypeptide comprising a second Fc domain comprising a CH2 domain (4) and a CH3 domain (5), wherein the first Fc domain and the second Fc domain associate with each other to form an Fc region.

[0021] While the embodiment of Format C ABM shown in Figures 3B-3D contains four binding domains (Fab1, Fab2, Fab3, and Fab4), Format C ABMs of the present disclosure may contain additional binding domains, e.g., scFv or Fab domains. However, in certain aspects, Fab1, Fab2, Fab3, and Fab4 are the sole binding domains of Format C ABMs of the present disclosure.

[0022] The Fab3 and Fab4 domains of Format C ABM can be non-binding (as shown in Figure 3B) or binding (as shown in Figures 3C and 3D). Those embodiments in which Fab3 and Fab4 are non-binding are generally referred to herein as Format C1 ABM, and this format may be referred to herein as the "clamp" format. Those embodiments in which Fab3 and Fab4 are binding are generally referred to herein as Format C2 ABM, and this format may be referred to herein as the "tandem Fab" format. The term "2+2 tandem Fab" refers to the embodiment shown in Figures 3C and 3D, in which Fab1, Fab2, Fab3, and Fab4 are the sole binding domains in the tandem Fab. Each of Format C1 and Format C2 ABM can be a homodimer or a heterodimer.

[0023] In certain embodiments of Format C1 ABM, the Fab1 and Fab2 domains are non-identical (e.g., bind to different epitopes, whether on the same or different target molecules), and the Fab3 and Fab4 domains are identical non-binding domains. In other embodiments, the Fab3 and Fab4 domains are different non-binding domains.

[0024] In a specific embodiment of format C2 ABM, the Fab1 and Fab3 domains comprise identical VH domains, and the Fab2 and Fab4 domains comprise identical VH domains, as shown in Figure 3C. This configuration is referred to as configuration 1, or 1-1-2-2 configuration. In an alternative embodiment of format C2 ABM, the Fab1 and Fab2 domains comprise identical VH domains, and the Fab3 and Fab4 domains comprise identical VH domains, as shown in Figure 3D. This configuration is referred to as configuration 2, or 1-2-1-2 configuration.

[0025] A complete ABM is formed by the association of two half antibodies through the two Fc domains that form the Fc region. If the two half antibodies are non-identical, e.g., Fab1 and Fab2 contain different VH domains, an Fc heterodimerization approach, e.g., as described in Section 6.2.7.2, can be utilized to facilitate correct half-antibody pairing and / or their purification. Examples of heterodimerization approaches are star mutations (described in Section 6.2.7.2) or knobs-in-holes mutations.

[0026] Although Figures 2B, 3A, 3B, and 3C show ABMs containing non-identical VH domains in each half antibody paired by an Fc heterodimer, this format can also be used for Fc homodimers. For example, Figures 2B and 3A show Format A and Format B ABMs, respectively, containing Fc heterodimers, but allow for the incorporation of different VH domains in Fab1 and Fab2 and the production of multispecific, e.g., bispecific, binding molecules. This format can also be used for Fc homodimers and monospecific Format A and Format B ABMs with identical VH domains. Similarly, Fc homodimers can be used to produce monospecific Format C ABMs with identical Fab1, Fab2, Fab3, and Fab4 VH domains, or identical Fab1 and Fab2 VH domains and non-binding Fab3 and Fab4 VH domains.

[0027] Furthermore, when the first and second polypeptides contain different VH domains, different strategies can be used to ensure correct VH-VL pairing in the multispecific binding molecule. For example, a common light chain can be used that can operably pair with two or more types of VH domains in the ABM. In such embodiments, the light chain polypeptides (e.g., Fab1 and Fab2, and, if present, the light chains associated with Fab3 and Fab4) can be identical. Alternatively, a single-domain Fab can be used in which the heavy chain components ((1) and (2)) can be expressed as a fusion with the light chain components ((6) and (7)).

[0028] The variations of the ABMs of the present disclosure shown in Figures 1-3 are not intended to be limiting, and the ABMs of the present disclosure can include any combination of the modifications shown in Figures 1-3 and in Section 6.2 below, among others. Additionally, reference to a first or second polypeptide chain or left or right half antibody is for convenience only and is not intended to convey that the polypeptide chains or half antibodies are produced or assembled in any particular order.

[0029] In some embodiments, the first Fab (Fab1) domain and the second Fab (Fab2) domain of an ABM of the present disclosure can each bind to the same target molecule, e.g., a small soluble molecule. The first Fab (Fab1) domain and the second Fab (Fab2) domain can bind to the same epitope (e.g., the embodiments shown in Figures 1B and 3D, or variations of Figures 3A or 3B, in which both Fab1 and Fab2 have identical VH domains (not shown)), or they can bind to different epitopes, whether on the same or different target molecules (e.g., the embodiments shown in Figures 2B, 3A, 3B, and 3C). When the first Fab (Fab1) domain and the second Fab (Fab2) domain bind to different epitopes, e.g., two different epitopes on the same or different target molecules, they can be selected so that the Fabs can simultaneously bind to those epitopes.

[0030] In some embodiments, for example, for Format C ABMs, the ABMs of the present disclosure can include a third Fab (Fab3) domain and a fourth Fab (Fab4) domain, as shown in Figures 3B, 3C, and 3D. The third and fourth Fab domains can be non-binding, as shown in Figure 3B, or binding, as shown in Figures 3C and 3D. When Fab3 and Fab4 are present, they can bind to the same or different epitopes as those bound by the Fab1 and Fab2 domains, respectively. For example, as shown in the embodiment of Figure 3C, Fab1 and Fab3 can share an epitope, and Fab2 and Fab4 can share an epitope. Alternatively, as shown in the embodiment of Figure 3D, Fab1 and Fab2 can share an epitope, and Fab3 and Fab4 can share an epitope. As used herein, with respect to Format C ABMs, the terms "first and second Fab domains" and "Fab1 and Fab2 domains" typically refer to the most N-terminal Fab domains, and references to "third and fourth Fab domains" and "Fab3 and Fab4 domains" typically refer to internal Fab domains.

[0031] Exemplary antigen-binding molecules of the present disclosure, including their components and configurations, and their target molecules, are described below in Sections 6.2 and 6.3, as well as in "A" specific embodiments 1-138 and "B" specific embodiments 1-72.

[0032] The present disclosure further provides conjugates, e.g., drug conjugates (for convenience, drug conjugates referred to herein as "antibody-drug conjugates" or "ADCs"), comprising the ABMs of the present disclosure. Exemplary features of the conjugates are described in Section 6.4, as well as in "A" specific embodiment 139 and "B" specific embodiment 73, below.

[0033] The present disclosure further provides nucleic acids encoding the ABMs of the present disclosure. The nucleic acids encoding the ABMs can be a single nucleic acid (e.g., a vector encoding all polypeptide chains of the ABM) or multiple nucleic acids (e.g., two or more vectors encoding different polypeptide chains of the ABM). The present disclosure further provides host cells and cell lines engineered to express the nucleic acids and ABMs of the present disclosure. The present disclosure further provides methods of producing the ABMs of the present disclosure. Exemplary nucleic acids, host cells, cell lines, and methods of producing the ABMs of the present disclosure are described in Section 6.5, below, "A" specific embodiments 144-145, and "B" specific embodiments 75-81.

[0034] The present disclosure further provides pharmaceutical compositions comprising the ABMs and ADCs of the present disclosure. Exemplary pharmaceutical compositions are described in Section 6.6, below, "A" specific embodiment 140, and "B" specific embodiment 74.

[0035] Further provided herein are methods of using the ABMs, conjugates, and pharmaceutical compositions of the present disclosure, for example, to treat conditions associated with the aberrant expression or activity of the target molecule to which they bind. Exemplary methods are described in Section 6.7, below, in "A" specific embodiments 141-143 and "B" specific embodiments 82-85. [Brief explanation of the drawings]

[0036] 5. Brief description of the drawings [Figure 1A]

[0023] Figure 1B is a schematic diagram of an exemplary homodimeric (monospecific, bivalent) Format A ABM of the present disclosure (Figure 1B) and the corresponding native antibody format (Figure 1A). Figure legend: (1) = VH, (2) = CH1, (3) = hinge, (4) = CH2, (5) = CH3, (6) = VL, (7) = CL, (8) = linker. [Figure 1B] Same as above. [Figure 2A]2B is a schematic diagram of the heterodimeric bispecific Format A ABM of the present disclosure (FIG. 2B) and the corresponding conventional bispecific antibody format (FIG. 2A). A small antigen (Ag) is shown to indicate potential ways in which the bispecific ABM may interact with the small antigen. Figure legend: (1) = VH, (2) = CH1, (3) = hinge, (4) = CH2, (5) = CH3, (6) = VL, (7) = CL, (8) = linker. An asterisk in one of the CH3 domains indicates that the two CH3s are not identical and contain one or more mutations (e.g., knob-in-hole mutations, star mutations, etc.) that allow heterodimerization. [Figure 2B] Same as above. [Figure 3A] 3A-3D are schematic diagrams of an exemplary Format B ABM (FIG. 3A) and an exemplary Format C ABM (FIGS. 3B-3D) of the present disclosure. Specific embodiments of the Format C ABMs shown are the exemplary heterodimer format C1 ABM (FIG. 3B), the exemplary heterodimer format C2 ABM (FIG. 3C), and the exemplary homodimer format C2 ABM (FIG. 3D). In some embodiments, these bispecific ABMs use a common light chain, VL-CL. In some embodiments of all formats, VH1-CH1 / VL-CL and VH2-CH1 / VL-CL are Fab fragments from non-competing mAbs to antigen. In the format shown in FIG. 3B (sometimes referred to herein as the "clamp" format), the internal Fab fragment, VH3-CH1 / VL-CL, does not bind to the target molecule. In the format shown in FIG. 3A (sometimes referred to herein as the "reach" format), the internal Fab is replaced with a flexible long linker. Figure legend: (1) = VH, (2) = CH1, (3) = hinge, (4) = CH2, (5) = CH3, (6) = VL, (7) = CL, (8) = linker. An asterisk in one of the CH3 domains indicates that the two CH3s are not identical and contain one or more mutations that allow heterodimerization (e.g., knob-in-hole mutations, star mutations, etc.). [Figure 3B] Same as above. [Figure 3C]Same as above. [Figure 3D] Same as above. [Figure 4A] Figure 4A shows the activity of TSLP parent Abs in a TSLP-blocking bioassay. Figure 4A shows the dose-response curve of hTSLP in a STAT3-luciferase reporter assay using Baf3 cells expressing both hIL7R and hTSLPR. Figure 4B shows the activity of selected TSLP Abs in the TSLP-blocking bioassay. TSLP Abs were incubated with the Baf3 / hIL7R / hTSLPR / STAT3-luciferase reporter cell line in the presence of 100 pM constant hTSLP. Luciferase activity was measured after 5.5 hours of incubation. [Figure 4B] Same as above. [Figure 5] Figure 1 shows graphs showing that anti-hTSLP bispecific IgG4 Abs exhibited similar TSLP-blocking activity as the corresponding parental Ab combinations. Anti-hTSLP parental Ab combinations and bispecific IgG4 Abs were compared for their activity in an hTSLP-blocking bioassay. TSLP Abs were incubated with a Baf3 / hIL7R / hTSLPR / STAT3-luciferase reporter cell line in the presence of 100 pM hTSLP. Luciferase activity was measured after 5.5 hours of incubation. [Figure 6A] Figure 6 shows a graph comparing different format bispecific anti-hTSLP Abs in a TSLP-blocking bioassay. Several parental Ab pairings were tested: 30206x30217 (Figure 6A), 30206x30230 (Figure 6B), and 30217x30230 (Figure 6C). TSLP Abs were incubated with a Baf3 / hIL7R / hTSLPR / STAT3-luciferase reporter cell line in the presence of 100 pM hTSLP. Luciferase activity was measured after 5.5 hours of incubation. "2xG4S" and "4xG4S" as disclosed in Figures 6A-6C are SEQ ID NO: 18 and SEQ ID NO: 19, respectively. [Figure 6B] Same as above. [Figure 6C] Same as above. [Figure 7]Figure 1 shows the fractograms of individual parental mAbs in the presence of hTSLP (REGN4009). The anti-TSLP mAb:hTSLP complex (solid line) was analyzed by asymmetric flow field fractionation coupled with multi-angle light scattering (A4F-MALS). Fractograms from individual samples of H4H30217P2 (gray dashed line) and hTSLP (black dashed line) are also overlaid. The relative UV absorbance at 215 nm as a function of retention time is shown for each sample, and the measured molar masses of the resolved peaks are indicated. [Figure 8] Figure 1 shows a graph depicting the fractograms of the parent mAb combination in the presence of hTSLP. The anti-TSLP mAb combination:hTSLP complex (solid line) was analyzed by asymmetric flow field fractionation coupled with multi-angle light scattering (A4F-MALS). Fractograms from individual samples of H4H30217P2 (gray dashed line) and hTSLP (black dashed line), as well as the H4H30217P2:hTSLP complex (black dotted line), are also overlaid. The relative UV absorbance at 215 nm as a function of retention time is shown for each sample, and the measured molar masses of the resolved peaks are indicated. [Figure 9] Figure 1 shows a graph depicting the fractogram of Fc-Fab bispecific Ab in the presence of hTSLP. The anti-TSLP Fc-Fab:hTSLP complex (solid line) was analyzed by asymmetric flow field fractionation coupled with multi-angle light scattering (A4F-MALS). Fractograms from individual samples of TS-FC1-eL1 (black dotted line), TS-FC6-eL2 (gray dotted line), and hTSLP (black dashed line) are also overlaid. The relative UV absorbance at 215 nm as a function of retention time is shown for each sample, and the measured molar masses of the resolved peaks are indicated. [Figure 10]Figure 1 shows a graph depicting the fractogram of clamp bispecific Ab in the presence of hTSLP. The anti-TSLP clamp:hTSLP complex (solid line) was analyzed by asymmetric flow field fractionation coupled with multi-angle light scattering (A4F-MALS). Fractograms from individual samples of TS-CL4-eL1 (black dotted line), TS-CL6-eL1 (gray dotted line), and hTSLP (black dashed line) are also overlaid. The relative UV absorbance at 215 nm as a function of retention time is shown for each sample, and the measured molar masses of the resolved peaks are indicated. [Figure 11] Figure 1 shows a graph depicting the fractogram of a 2+2 tandem Fab bispecific Ab in the presence of hTSLP. The anti-TSLP 2+2 tandem Fab:hTSLP complex (solid line) was analyzed by asymmetric flow field fractionation coupled with multi-angle light scattering (A4F-MALS). Fractograms from individual samples of TS-CL2-eL2 (black dotted line), TS-CL3-eL2 (gray dotted line), and hTSLP (black dashed line) are also overlaid. The relative UV absorbance at 215 nm as a function of retention time is shown for each sample, and the measured molar masses of the resolved peaks are indicated. [Figure 12] Figure 12 is a graph comparing the activity of anti-hTSLP 30217x30230 bispecific Fc-Fabs with different linker lengths in a TSLP-blocking bioassay. TSLP Abs were incubated with a Baf3 / hIL7R / hTSLPR / STAT3-luciferase reporter cell line in the presence of 120 pM constant hTSLP. Luciferase activity was measured after 5.5 hours of incubation. All values were normalized to STAT3-luciferase activity in the absence of TSLP-blocking Abs and expressed as a percentage of STAT3-Luc activity. The G4S, (G4S)2, (G4S)3, (G4S)4, (G4S)5, and (G4S)6 linkers disclosed in Figure 12 are SEQ ID NOs: 3, 18, 4, 19, 39, and 38, respectively. [Figure 13A]Figures 13A-13C are schematic diagrams of different hinge formats: Figure 13A: Hinge format 1, shown with the hinge sequence ESKYGPPCPPC (SEQ ID NO: 2) and a (G4S)n linker (G4S is disclosed as SEQ ID NO: 3); Figure 13B: Hinge format 2, shown with the hinge sequence ESKYGPPCPPC (SEQ ID NO: 2) and a (G4S)n linker (G4S is disclosed as SEQ ID NO: 3); Figure 13C: Hinge format 3, shown with the hinge sequence GGGGSCPPC (SEQ ID NO: 1) and a (G4S)n linker (G4S is disclosed as SEQ ID NO: 3). Figure 13D is a graph showing the activity of 30217x30230 Fc-Fabs with different hinge formats (hinge format 1 with a G4S linker (SEQ ID NO: 3), hinge format 2 with a G4S linker (SEQ ID NO: 3), hinge format 3 with a G4S linker (SEQ ID NO: 3), hinge format 1 with a (G4S)4 linker (SEQ ID NO: 19), hinge format 2 with a (G4S)4 linker (SEQ ID NO: 19), and hinge format 3 with a (G4S)4 linker (SEQ ID NO: 19). TSLP Abs were incubated with the Baf3 / hIL7R / hTSLPR / STAT3-luciferase reporter cell line in the presence of 120 pM hTSLP. Luciferase activity was measured after 5.5 hours of incubation. All values were normalized to STAT3-luciferase activity in the absence of TSLP-blocking Ab and expressed as a percentage of STAT3-Luc activity. [Figure 13B] Same as above. [Figure 13C] Same as above. [Figure 13D] Same as above. [Figure 14] Pharmacokinetic profiles of molar equivalents of the anti-TSLP bispecific Fc-Fab molecules REGN8759 and REGN8760, the hIgG4 isotype control REGN1945, the conventional hIgG4 bispecific isotype control H4H21237D, and the hFcγ homodimer REGN1627 in WT mice are shown. [Figure 15]Pharmacokinetic profiles of molar equivalents of anti-TSLP Fc-Fab antibodies REGN8759 and REGN8760, hIgG4 isotype control REGN1945, conventional hIgG4 bispecific isotype control H4H21237D, and hFcγ homodimer REGN1627 in WT mice are shown. [Figure 16A] 16A-C are graphs comparing the inhibitory activity of anti-ligand X parental mAbs mAbX1 and mAbX2, and bispecific Fc-Fab mAbX1 x mAbX2 in a ligand X signaling bioassay. Anti-ligand X Ab was incubated with a luciferase reporter cell line engineered for receptor X signaling in the presence of 10 pM (FIG. 16A), 100 pM (FIG. 16B), or 1 nM (FIG. 16C) of constant human ligand X. Luciferase activity was measured after 5.5 hours of incubation. [Figure 16B] Same as above. [Figure 16C] Same as above. [Figure 17A] 17A-C are graphs comparing the inhibitory activity of anti-ligand X parental mAbs mAbX2 and mAbX3, and the bispecific Fc-Fab mAbX2 x mAbX3 in a ligand X signaling bioassay. Anti-ligand X Ab was incubated with a luciferase reporter cell line engineered for receptor X signaling in the presence of 10 pM (FIG. 17A), 100 pM (FIG. 17B), or 1 nM (FIG. 17C) of constant human ligand X. Luciferase activity was measured after 5.5 hours of incubation. [Figure 17B] Same as above. [Figure 17C] Same as above. [Figure 18A]18A-C are graphs comparing the inhibitory activity of anti-ligand X parental mAbs mAbX1 and mAbX3, and the bispecific Fc-Fab mAbX1 x mAbX3 in a ligand X signaling bioassay. Anti-ligand X Ab was incubated with a luciferase reporter cell line engineered for receptor X signaling in the presence of 10 pM (FIG. 18A), 100 pM (FIG. 18B), or 1 nM (FIG. 18C) of constant human ligand X. Luciferase activity was measured after 5.5 hours of incubation. [Figure 18B] Same as above. [Figure 18C] Same as above. [Figure 19A] 19A and 19B show fractograms of a complex of Ligand X and an anti-Ligand X antibody. The anti-Ligand X antibody in combination with Ligand X was analyzed by asymmetric flow field fractionation coupled with multi-angle light scattering (A4F-MALS). Fractograms from individual samples of antibody and Ligand X are also overlaid. The relative UV absorbance at 215 nm as a function of retention time is shown for each sample, and the measured molar masses of resolved peaks are indicated. Figures 19A and 19B show fractograms of parent antibodies mAbX1, mAbX2, and Ligand X; Figure 19C shows a fractogram of mAbX1 x mAbX2 Fc-Fab and Ligand X; Figure 19D shows a fractogram of mAbX1 x mAbX2 clamp and Ligand X; and Figure 19E shows a fractogram of the mAbX1 x mAbX2 2+2 tandem Fab heterodimer and Ligand X. [Figure 19B] Same as above. [Figure 19C] Same as above. [Figure 19D] Same as above. [Figure 19E] Same as above. [Figure 20A]Figures 20A, 20B, 20C, and 20D show graphs showing binding of antigen Y Fc-Fabs to antigen Y-expressing cells as measured in a FACS-based assay. Figure 20A shows anti-antigen Y IgG1 mAb mAbY1 cloned as an IgG1 Fc-Fab with G4S linkers of different lengths (G4S is disclosed as SEQ ID NO: 3). The Fc-Fab and parental IgG1 mAb showed similar binding to cell surface antigen Y. Figures 20B, 20C, and 20D show anti-antigen Y IgG4 mAbs mAbY2, mAbY3, and mAbY4 cloned as IgG4 Fc-Fabs with different G4S linkers (G4S is disclosed as SEQ ID NO: 3). All Fc-Fabs showed strong activity in the antigen Y FACS binding assay. "1xG4S," "2xG4S," "3xG4S," "4xG4S," and "5xG4S" disclosed in Figures 20A to 20D are SEQ ID NOs: 3, 18, 4, 19, and 39, respectively. [Figure 20B] Same as above. [Figure 20C] Same as above. [Figure 20D] Same as above. [Figure 21A] 21A-21B are graphs showing binding of anti-CD3 and anti-antigen Z Fc-Fabs to cell surface epitopes in a FACS-based assay. Anti-CD3 (FIG. 21A) and anti-antigen Z (FIG. 21B) Abs were cloned as IgG1 Fc-Fabs with G4S linkers of different lengths (G4S is disclosed as SEQ ID NO: 3). These Fc-Fabs showed specific binding to cell surface CD3 (FIG. 21A) and antigen Z (FIG. 21B). "1xG4S," "2xG4S," "3xG4S," "4xG4S," and "5xG4S" disclosed in FIGS. 21A-21B are SEQ ID NOs: 3, 18, 4, 19, and 39, respectively. [Figure 21B] Same as above. [Figure 22A]Figures 22A-22B are graphs showing that CD3xAntigenZ bispecific Fc-Fab was active in bioassays. Figure 22A: CD3xAntigenZ bispecific Fc-Fab activated TCR signaling in Jurkat / NFAT-luciferase reporter cells in the presence of AntigenZ+ cells. Figure 22B: CD3xAntigenZ bispecific Fc-Fab caused killing of AntigenZ+ cells by pre-activated human donor T cells in a 3-hour calcein release assay. "1xG4S," "2xG4S," and "3xG4S" disclosed in Figures 22A-22B are SEQ ID NOs: 3, 18, and 4, respectively. [Figure 22B] Same as above. DETAILED DESCRIPTION OF THE INVENTION

[0037] 6. MODE FOR CARRYING OUT THE INVENTION 6.1.Definition As used herein, the following terms are intended to have the following meanings:

[0038] Antibody: As used herein, the term "antibody" refers to any antigen-binding molecule or molecular complex containing at least one complementarity-determining region (CDR) that specifically binds to or interacts with a particular antigen. The term "antibody" includes conventional immunoglobulin molecules, including four polypeptide chains, two heavy (H) chains, and two light (L) chains, interconnected by disulfide bonds, as well as multimers thereof (e.g., IgM). Each heavy chain contains a heavy chain variable region (abbreviated herein as HCVR or VH) and a heavy chain constant region. The heavy chain constant region contains three domains, CH1, CH2, and CH3. Each light chain contains a light chain variable region (abbreviated herein as LCVR or VL) and a light chain constant region. The light chain constant region contains one domain (CL1). The VH and VL regions can be further subdivided into regions of hypervariability called complementarity-determining regions (CDRs), interspersed with more conserved regions called framework regions (FRs). Each VH and VL is composed of three CDRs and four FRs arranged from the amino terminus to the carboxy terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. An amino acid consensus sequence can be defined based on a parallel analysis of two or more CDRs.

[0039] The term "antibody" as used herein also includes antigen-binding fragments of complete antibody molecules. "Antigen-binding portion" of an antibody, "antigen-binding fragment" of an antibody, and similar terms, as used herein, include naturally occurring, enzymatically obtained, synthetic, or genetically engineered polypeptides or glycoproteins that specifically bind antigens to form complexes. Antibody-binding fragments of antibodies can be derived from complete antibody molecules using any suitable standard techniques, such as, for example, proteolytic or recombinant genetic engineering techniques involving the manipulation and expression of DNA encoding antibody variable and, optionally, constant domains. Such DNA is known and / or readily available, for example, from commercial sources, DNA libraries (including, for example, phage-antibody libraries), or can be synthesized. DNA can be sequenced and manipulated, for example, chemically or by using molecular biology techniques, to arrange one or more variable and / or constant domains into a suitable configuration, or to introduce codons, create cysteine residues, modify, add, or delete amino acids, etc.

[0040] Non-limiting examples of antigen-binding fragments include (i) Fab fragments, (ii) F(ab')2 fragments, (iii) Fd fragments, (iv) Fv fragments, (v) single-chain Fv (scFv) molecules, (vi) dAb fragments, and (vii) minimal recognition units consisting of amino acid residues mimicking a hypervariable region of an antibody (e.g., an isolated complementarity-determining region (CDR) such as a CDR3 peptide), or a constrained FR3-CDR3-FR4 peptide. Domain-specific antibodies, single-domain antibodies, domain-deleted antibodies, chimeric antibodies, CDR-grafted antibodies, diabodies, triabodies, tetrabodies, minibodies, nanobodies (e.g., monovalent nanobodies, bivalent nanobodies, etc.), small modular immunopharmaceuticals (SMIPs), and other engineered molecules such as shark variable IgNAR domains are also encompassed by the term "antigen-binding fragment" as used herein.

[0041] Antigen-binding fragments of antibodies typically contain at least one variable domain. The variable domain can be of any size or amino acid composition and generally contains at least one CDR adjacent to or in-frame with one or more framework sequences. In antibody-binding fragments having a VH domain associated with a VL domain, the VH and VL domains can be arranged relative to each other in any suitable configuration. For example, the variable region can be a dimer and contain a VH-VH, VH-VL, or VL-VL dimer. Alternatively, the antigen-binding fragment of an antibody can contain a monomeric VH or VL domain.

[0042] In certain embodiments, an antigen-binding fragment of an antibody may contain at least one variable domain covalently linked to at least one constant domain. Non-limiting exemplary configurations of variable and constant domains that may be found in an antigen-binding fragment of an antibody of the present disclosure include: (i) VH-CH1, (ii) VH-CH2, (iii) VH-CH3, (iv) VH-CH1-CH2, (v) VH-CH1-CH2-CH3, (vi) VH-CH2-CH3, (vii) VH-CL, (viii) VL-CH1, (ix) VL-CH2, (x) VL-CH3, (xi) VL-CH1-CH2, (xii) VL-CH1-CH2-CH3, (xiii) VL-CH2-CH3, and (xiv) VL-CL. In any configuration of variable and constant domains, including any of the exemplary configurations listed above, the variable and constant domains may be directly linked to each other or may be linked by a complete or partial hinge or linker region. The hinge region may consist of at least two (e.g., 5, 10, 15, 20, 40, 60 or more) amino acids that provide a flexible or semi-flexible link between adjacent variable and / or constant domains in a single polypeptide molecule. Furthermore, antigen-binding fragments of antibodies of the present disclosure may comprise homodimers or heterodimers (or other multimers) of any of the variable and constant domain configurations listed above in non-covalent association with each other and / or with one or more monomeric VH or VL domains (e.g., via disulfide bonds).

[0043] Like intact antibody molecules, antibody-binding fragments can be monospecific or multispecific (e.g., bispecific). Multispecific antigen-binding fragments of antibodies typically contain at least two different variable domains, each capable of specifically binding to a separate antigen or to a different epitope on the same antigen. Any multispecific antibody format, including the exemplary bispecific antibody formats disclosed herein, can be adapted for use in the context of the antigen-binding fragments of antibodies of the present invention using routine techniques available in the art.

[0044] Antigen-binding molecule or ABM: As used herein, the term "antigen-binding molecule" or "ABM" refers to a molecule (e.g., an assembly of multiple polypeptide chains) comprising two half antibodies. Typically, each half antibody comprises at least one antigen-binding site. ABMs of the present disclosure can be monospecific or multispecific (e.g., bispecific). The antigen-binding sites of a monospecific binding molecule all bind to the same epitope, whereas a multispecific binding molecule has at least two antigen-binding sites that bind to different epitopes, which can be the same or different target molecules.

[0045] Association: The term "association" in the context of an ABM refers to a functional relationship between two or more polypeptide chains. In particular, the term "association" means that two or more polypeptides are associated with each other, for example, non-covalently through molecular interactions or covalently through one or more disulfide or chemical bridges, to produce a functional ABM in which the antigen-binding sites are capable of binding to their respective targets. Examples of associations that may be present in the ABMs of the present disclosure include (but are not limited to) the association between homodimeric or heterodimeric Fc domains in the Fc region, the association between VH and VL regions in the Fab domain, the association between CH1 and CL in the Fab domain, and the association between CH3 and CH3 in a domain-substituted Fab.

[0046] Bivalent: As used herein, the term "bivalent" refers to an ABM having two antigen-binding sites. In some embodiments, the two antigen-binding sites bind to the same epitope of the same target. In other embodiments, the two antigen-binding sites specifically bind to different epitopes, whether to the same or different target molecules.

[0047] Complementarity-determining region or CDR: As used herein, the term "complementarity-determining region" or "CDR" refers to the sequence of amino acids in an antibody variable region that confers antigen specificity and binding affinity. Generally, each heavy chain variable region has three CDRs (CDR-H1, CDR-H2, HCDR-H3), and each light chain variable region has three CDRs (CDR1-L1, CDR-L2, CDR-L3). Exemplary rules that can be used to identify the boundaries of CDRs include, for example, the Kabat definition, the Chothia definition, the ABS definition, and the IMGT definition. See, e.g., Kabat, 1991, "Sequences of Proteins of Immunological Interest," National Institutes of Health, Bethesda, Md. (Kabat numbering scheme); Al-Lazikani et al., 1997, J. Mol. Biol. 273:927-948 (Chothia numbering scheme); Martin et al., 1989, Proc. Natl. Acad. Sci. USA 86:9268-9272 (ABS numbering scheme); and Lefranc et al., 2003, Dev. Comp. Immunol. 27:55-77 (IMGT numbering scheme). Public databases are also available for identifying CDR sequences within antibodies.

[0048] Cytokine: The term "cytokine" refers to any member of a group of low-molecular-weight extracellular polypeptides / glycoproteins with cell signaling activity, including chemokines, interferons, interleukins, lymphokines, and tumor necrosis factors. Cytokines are involved in regulating immune responses (e.g., the activity, differentiation, proliferation, and production of cells and other cytokines) and are typically synthesized by immune cells, primarily T cells, neutrophils, and macrophages, but can also be synthesized by non-immune cells. Cytokines exist as monomers, dimers (both homodimers and heterodimers), trimers (including homotrimers), and tetramers (including homotetramers). Cytokines range in molecular weight from approximately 5 to 70 kDa, with the majority ranging from approximately 5 to approximately 20 kDa. Many cytokines share a four-alpha-helical bundle structure. Other cytokines are characterized by a cysteine knot, which contains three disulfide bridges formed from pairs of cysteine residues. Additional cytokines are characterized by a homodimeric pyramidal structure, a feature sometimes present in cell surface proteins.

[0049] EC50: The term "EC50" refers to the half-maximal effective concentration of an antibody or ABM that induces a response midway between baseline and maximum after a specific exposure time. EC50 essentially represents the concentration of an antibody or ABM at which 50% of its maximum effect is observed. In certain embodiments, the EC50 value is equal to the concentration of an antibody or ABM that confers half-maximal binding to cells expressing a target molecule that can be specifically bound by the antibody or ABM, as determined, for example, by a FACS binding assay. Thus, reduced or weaker binding is observed at an increased EC50, or half-maximal effective concentration value. The EC50 values of the ABMs of the present disclosure are, in some embodiments, about 10 -5 M or less (e.g., 10 -5 Under M, 10 -6 Under M, 10 -7 Under M, 10 -8 Less than M or 10 -9 M or less).

[0050] Epitope: The term "epitope" refers to an antigenic determinant that interacts with a specific antigen-binding site in the variable region of an antibody or antigen-binding molecule, known as the paratope. A single antigen or target molecule may have two or more epitopes. Thus, different antibodies or antigen-binding molecules may bind to different regions on the antigen or target molecule and have different biological effects. Epitopes can be either conformational or linear. Conformational epitopes are generated by spatially juxtaposed amino acids from different segments of a linear polypeptide chain. Linear epitopes are generated by adjacent amino acid residues in a polypeptide chain. In certain circumstances, epitopes may include sugar, phosphoryl, or sulfonyl moieties on an antigen or target molecule.

[0051] Fab: The term "Fab" in the context of the ABMs of the present disclosure refers to a pair of polypeptide chains, the first of which comprises an antibody variable heavy (VH) domain (referred to herein as C1) N-terminal to the first constant domain, and the second of which comprises an antibody variable light (VL) domain (referred to herein as C2) N-terminal to a second constant domain capable of pairing with the first constant domain. In native immunoglobulins, the VH is N-terminal to the first constant domain (CH1) of the heavy chain, and the VL is N-terminal to the constant domain of the light chain (CL). The Fabs of the present disclosure, particularly when the ABMs of the present disclosure comprise non-identical Fabs, may be oriented according to their natural orientation or may include domain substitutions or swaps that promote correct VH and VL pairing. For example, the pair of CH1 and CL domains in a Fab may be replaced with a pair of CH3 domains to promote correct modified Fab chain pairing in the heterodimeric ABM. It is also possible to reverse the CH1 and CL, attaching CH1 to VL and CL to VH, a configuration commonly known as a crossmab. Alternatively, or in addition to using substituted or swapped constant domains, correct chain pairing can be achieved by using a universal light chain that can pair with both variable regions of the heterodimeric ABM of the present disclosure. In describing the ABMs of the present disclosure, the C1 domain is referred to elsewhere herein as the CH1 domain, and the C2 domain is referred to herein as the CL domain for each description, but domain-swapped formats are also intended to be included. Other forms of engineered Fabs are exemplified in Section 6.2.1.

[0052] Fc: The term "Fc" refers to a portion of the heavy chain constant region comprising at least the CH2 and CH3 domains that typically bind to an Fc receptor, e.g., FcγR, i.e., FcγRI (CD64), FcγRII (CD32), FcγRIII (CD16), or FcRn, i.e., neonatal Fc receptor. The term "Fc" also encompasses engineered Fc that differ from the Fc of a native immunoglobulin. For example, the CH2 and CH3 regions can be engineered to contain deletions, substitutions, and / or insertions, or other modifications that render them incapable of binding to any Fc receptor; the CH2 and CH3 regions are then considered non-functional with respect to their typical biological function. Other forms of engineered Fc are exemplified in Section 6.2.7.

[0053] Fc domain and Fc region: The term "Fc domain" refers to the portion of a heavy chain that pairs with the corresponding portion of another heavy chain. The term "Fc region" refers to the region of an antibody-based binding molecule formed by the association of two heavy chain Fc domains. The two Fc domains within an Fc region can be the same or different from one another. In natural antibodies, the Fc domains are typically identical, but for purposes of producing the ABMs of the present disclosure, one or both Fc domains can be advantageously modified to allow heterodimerization.

[0054] Half antibody: The term "half antibody" refers to a molecule that contains at least an Fc domain and can associate with another molecule that contains an Fc domain, e.g., through disulfide bridges or molecular interactions (e.g., knob-in-hole interactions between Fc heterodimers). Half antibodies can be composed of one polypeptide chain or two or more polypeptide chains (e.g., heavy and light chains).

[0055] Heavy chain: As used herein, the term "heavy chain" or "immunoglobulin (Ig) heavy chain" includes an Ig heavy chain constant region sequence from any organism, and includes a heavy chain variable domain unless otherwise specified. The heavy chain variable domain includes three heavy chain complementarity-determining regions (CDRs) and four framework regions (FRs), unless otherwise specified. A fragment of a heavy chain variable domain includes the CDRs or both the CDRs and FRs. A typical heavy chain constant region (CH) has, following the variable domain, from N- to C-terminus, a CH1 domain, a hinge, a CH2 domain, and a CH3 domain (see, e.g., Figures 1A and 2A). Atypical heavy chains, such as those disclosed herein for antigen-binding molecules and bispecific heavy antigen-binding molecules, have a variable domain (VH) between any two of the heavy chain constant regions (CHs), e.g., from N- to C-terminus, a CH2 domain, a CH3 domain, a VH domain, and a CH2 domain (see, e.g., Figures 1B and 2B). In one embodiment, the Fc portion comprises at least a CH2 and a CH3 domain.

[0056] Hinge: As used herein, the term "hinge" is intended to include the region of consecutive amino acid residues connecting the C-terminus of the CH1 domain to the N-terminus of the CH2 domain of an immunoglobulin. Several amino acids at the N-terminus of the CH2 domain, encoded by the CH2 exon, are also considered part of the "lower hinge." Without being bound by any one theory, the amino acids in the hinge regions of IgG1, IgG2, and IgG4 have been characterized as including 12-15 consecutive amino acids encoded by different hinge exons and several N-terminal amino acids of the CH2 domain (encoded by the CH2 exon) (Brekke et al., 1995, Immunology Today 16(2):85-90). On the other hand, IgG3 contains a hinge region consisting of four segments: one upper segment resembling the hinge region of IgG1, and three segments of identical amino acid repeats unique to IgG3.

[0057] Host cell: As used herein, the term "host cell" refers to a cell into which a nucleic acid of the present disclosure has been introduced. The terms "host cell" and "recombinant host cell" are used interchangeably herein. It is understood that such terms refer to the particular subject cell and the progeny or potential progeny of such a cell. Because certain modifications may occur in subsequent generations due to either mutation or environmental influences, such progeny may not, in fact, be identical to the parent cell but still fall within the scope of the term as used herein. Typical host cells are eukaryotic host cells, such as mammalian host cells. Exemplary eukaryotic host cells include yeast and mammalian cells, e.g., vertebrate cells such as mouse, rat, monkey, or human cell lines, e.g., HKB11 cells, PER.C6 cells, HEK cells, or CHO cells.

[0058] Immunoglobulin: The term "immunoglobulin" (Ig) refers to a class of structurally related glycoproteins consisting of two pairs of polypeptide chains, one pair of light (L) chains, and one pair of heavy (H) chains, all four of which may be interconnected by disulfide bonds. The structure of immunoglobulins has been well characterized. See, for example, Fundamental Immunology Ch. 7 (Paul, W., ed., 2nd ed. Raven Press, NY (1989)). Each heavy chain typically contains a heavy chain variable region (abbreviated herein as VH or VH) and a heavy chain constant region (CH or CH). The heavy chain constant region typically contains three domains, CH1, CH2, and CH3. The CH1 and CH2 domains are connected by a hinge. The Fc portion contains at least the CH2 and CH3 domains.

[0059] Typically, the numbering of amino acid residues in immunoglobulins is according to IMGT, Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD. (1991), or according to Kabat's EU numbering system (also known as "EU numbering" or "EU index"), as described, for example, in Kabat et al. Sequences of Proteins of Immunological Interest. 5th ed. US Department of Health and Human Services, NIH publication No. 91-3242 (1991).

[0060] Isotype: The term "isotype" refers to the immunoglobulin class or subclass (e.g., IgG1, IgG2, IgG3, IgG4, IgD, IgA, IgE, or IgM) encoded by heavy chain constant region genes.

[0061] Operably linked: The term "operably linked" refers to the physical or functional juxtaposition of the described components that permits the components to function in their intended manner. With respect to polypeptides, the term "operably linked" can refer to the functional relationship between two or more regions of a polypeptide chain, where two or more regions are joined to produce a functional polypeptide. With respect to nucleic acids, such as in the context of a DNA expression vector construct, the term "operably linked" refers, for example, to a control sequence, e.g., a promoter or operator, suitably positioned relative to a coding sequence such that the control sequence directs production of the polypeptide encoded by the coding sequence.

[0062] Polypeptides and Proteins: The term "protein" is meant to include quaternary, ternary, and other complex macromolecules composed of at least one polypeptide. The term "protein" includes polypeptides.

[0063] The term "polypeptide" refers to a single, linear polymeric chain of amino acids joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. Polypeptides of the present disclosure include amino acid sequences derived from immunoglobulin domains. A polypeptide or amino acid sequence "derived from" a designated protein or polypeptide refers to the origin of the polypeptide.

[0064] The term "protein" can also be used to describe large polypeptides, such as those made up of one or more polypeptides.

[0065] Single-chain Fab: As used herein, the term "single-chain Fab" or "scFab" refers to a polypeptide chain comprising the VH, CH1, VL, and CL domains of an antibody, wherein these domains are present in a single polypeptide chain.

[0066] Single-chain Fv or scFv: As used herein, the term "single-chain Fv" or "scFv" refers to a polypeptide chain comprising the VH and VL domains of an antibody, wherein these domains are present in a single polypeptide chain.

[0067] Specifically (or selectively) binds: As used herein, the term "specifically (or selectively) binds" means that the ABM or antigen binding site ("ABS") forms a complex with the target molecule that is relatively stable under physiological conditions. Specific binding is defined as binding of approximately 5x10 -2 M or less (e.g., 5x10 -2 Under M, 10 -2 Under M, 5x10 -3 Under M, 10 -3 Under M, 5x10 -4 Under M, 10 -4Under M, 5x10 -5 Under M, 10 -5 Under M, 5x10 -6 Under M, 10 -6 Under M, 5x10 -7 Under M, 10 -7 Under M, 5x10 -8 Under M, 10 -8 Under M, 5x10 -9 Under M, 10 -9 Less than M or 10 -10 The binding affinity of an antibody or antibody fragment, e.g., an ABM or ABS, to a target molecule can be characterized by a KD of less than M. Methods for determining the binding affinity of an antibody or antibody fragment, e.g., an ABM or ABS, to a target molecule are well known in the art and include, for example, equilibrium dialysis, surface plasmon resonance (e.g., a Biacore assay), fluorescence-activated cell sorting (FACS) binding assays, and the like. An ABM or ABS antibody that specifically binds to a target molecule from one species may, however, have cross-reactivity to target molecules from one or more other species.

[0068] Target molecule: As used herein, the term "target molecule" refers to any biomolecule (e.g., a protein, carbohydrate, lipid, or a combination thereof) that can be specifically bound by the antigen-binding site of an ABM. Exemplary target molecules include, but are not limited to, ABCF1, ACVR1, ACVR1B, ACVR2, ACVR2B, ACVRLI, ADORA2A, aggrecan, AGR2, AICDA, AIF1, AIG1, AKAP1, AKAP2, AMH, AMHR2, ANGPT1, ANGPT2, ANGPTL3, ANGPTL4, ANPEP, APC, APOC1, AR, AZGP1 (zinc-α-glycoprotein), ART-4, B7, B7.1, B7.2, BAD, BAFF, BAGI, BAIi, B CL2, BCL6, BDNF, BLNK, BLRl (MDRlS), BlyS, BMPl, BMP2, BMP3B (GDF10), BMP4, BMP6, BMPS, BMPR1A, BMPR1B, BMPR2, BPAG1 (plectin), BRCA1 , Ba-733, BAGE, BrE3-antigen, CA125, CAMEL, CAP-I, CASP-8 / m, CCCL19, CCCL21, CD1, CD1a, CD2, CD3, CD4, CDS, CD8, CDI-IA, CD14, CD15, CD16, CD18, CD19, CD20, CD21, CD22, CD23, CD25, CD29, CD30, CD32b, CD33, CD37, CD38, CD40, CD40L, CD45, CD46, CD54, CD55, CD59, CD64, CD66a -e, CD67, CD70, CD74, CD79a, CD80, CD83, CD95, CD126, CD133, CD138, CD147, CD154, CDC27, CDK-4 / m, CDKN2A, CXCR4, CXCR7, CXCL12, C19o rf10(IL27w), C3, C4A, CS, CSR1, CANT1, CASPI, CASP4, CAV1, CCBP2(D6 / JAB61), CCLI(I-309), CCLII(eotaxin), CCL13(MCP-4), CCLIS(MI P-1d), CCL16 (HCC-4), CCL17 (TARC), CCLIS (PARC), CCL19 (MIP-3b), CCL2 (MCP-1), MCAF, CCL20 (MIP-3a), CCL21 (MIP-2), SLC, Exodus-2,CCL22(MDC / STC-1)、CCL23(MPIF-1)、CCL24(MPIF-2 / エオタキシン-2)、CCL2S(TECK)、CCL26(エオタキシン-3)、CCL27(CTACK / ILC)、CCL2S、CCL3(MIP1a)、CCL4(MIP-1b)、CCLS(RANTES)、CCL7(MCP-3)、CCLS(mcp-2)、CCNA1、CCNA2、CCND1、CCNE1、CCNE2、CCR1(CKR1 / HM14S)、CCR2(mcp-1RB / RA)、CCR3(CKR3 / CMKBR3)、CCR4、CCRS(CMKBRSI ChemR13)、CCR6(CMKBR6 / CKR-L3 / STRL22 / DRY6)、CCR7(CKR7 / EB1)、CCRS(CMKBRS / TER1 / CKR-LI)、CCR9(GPR-9-6)、CCRLI(VSHK1)、CCRL2(L-CCR)、CD164、CDlC、CD200、CD-22、CD24、CD2S、CD3S、CD3E、CD3G、CD3Z、CD4、CD44、CD4SRB、CD47、CD4S、CDS2、CD69、CD72、CD79A、CD79B、CDSO、CDS1、CDS3、CDS6、CD137、CD13S、B7-1、B7-2、ICOSL、B7-H3、B7-H4、CD137L、OX40L、CDH1(E-カドヘリン)、CDH10、CDH12、CDH13、CDHlS、CDH19、CDH20、CDHS、CDH7、CDHS、CDH9、CDK2、CDK3、CDK4、CDKS、CDK6、CDK7、CDK9、CDKN1A(p21 Wap1 / Cip1)、CDKN1B(p27Kip1)、CDKN1C、CDKN2A(p16INK4a)、CDKN2B、CDKN2C、CDKN3、CEBPB、CER1、CHGA、CHGB、キチナーゼ、CHST1O、CKLFSF2、CKLFSF3、CKLFSF4、CKLFSFS、CKLFSF6、CKLFSF7、CKLFSFS、CLDN3、CLDN7(クローディン-7)、CLN3、CLU(クラステリン)、CMKLR1、CMKOR1(RDC1)、CNR1、COLISA1、COLIA1、COL4A3、COL6Al、CR2、CRP、CSF1(M-CSF)、CSF2(GM-CSF)、CSF3(GCSF)、CTLA-4、CTNNB1(b-カテニン), CTSB(カテプシンB), CX3CLI(SCYD1), CX3CR1(V2S), CXCLI(GR O1), CXCLIO(IP-10), CXCL11(I-TAC / IP-9), CXCL13, CXCL14, CXCL16, CXCL2 (GR02), CXCL3(GR03), CXCLS(ENA-7S / LIX), CXCL6(GCP-2), CXCL9(MIG), CXCR3(GPR9 / CKR-L2), CXCR6(TYMSTR / STRL33 / Bonzo), CYBS, CYC1, CYSLTR1, HIF-1-a, colon-specific antigen-p (CSAp), CEA (CEACAM5), CEACAM6, c-met, DAB2IP, DES, DKFZp4S1J011S, DNCLI, DPP4, DAM, EGFR, EGFRvllll, EGP-1, EGP-2, ELF2-M, E p-CAM, E2F1, ECGF1, EDG1, EFNA1, EFNA3, EFNB2, EGF, EGFR, ELAC2, ENG, EN01, EN02, EN03, EPHB4, EPO, EREG, ERKS, ESR1, ESR2, F3(TF), FADD, FasL, FASN , FCER1A, FCER2, FCGR3A, FGF, FGF1(aFGF), FGF10, FGF11, FGF12, FGF12B, FGF13, FGF14, FGF16, FGF17, FGF1S, FGF19, FGF2(bFGF), FGF20, FGF21, FGF22 , FGF23, FGF3(int-2), FGF4(HST), FGFS, FGF7(KGF), FGFS, FGF9, FGFR3, FIGF(VEGFD), FILI(EPSILON), FILI(ZETA), FLJ12SS4, FLJ2SS30, FLRT1(フィブロネクチン), FOS, FOSLI(FRA-1), FY(DARC), Flt-I, Flt-3, folate receptor, G250 antigen, GAGE, GROB, GABRP(GABAa), GAGEB1, GAGEC1, GALNAC4S-6ST, GATA3, GDFS, GFil, G GTl, GM-CSF, GNAS1, GNRH1, GPR2(CCR10), GPR31, GPR44, GPRS1(FKSGSO), GRCC10(C10), GRP, GSN(ゲルソリン), GSTP1, HAVCR2, HDAC4, HDACS, HDAC7A, HDAC9,HGF, HIP1 histamine and histamine receptor, HLA-A, HLA-DRA, HM74, HMOX1, HUMCYT2A, HLA-DR, HMI 24, human chorionic gonadotropin (HCG) and its subunits, HER2 / neu, HMGB-1, hypoxia-inducible factor (HIF-1), HSP70-2M, HST-2 or 1a, IGF-IR,

number

[0069] Tetravalent: As used herein, the term "tetravalent" refers to an ABM having four antigen-binding sites. In some embodiments, two of the antigen-binding sites bind to the same epitope, and the other two binding sites bind to different epitopes, whether to the same or different target molecules.

[0070] Universal heavy chain: The term "universal heavy chain" used herein in the context of ABM refers to a heavy chain with a rearranged heavy chain variable region, for example, a human heavy chain with a rearranged Ig heavy chain variable region. Exemplary rearranged Ig heavy chain variable regions are provided in U.S. Patent Publication No. 2014 / 0245468 and U.S. Patent Nos. 9,204,624 and 9,930,871, each of which is incorporated herein by reference in its entirety. Universal heavy chains are also known as "common heavy chains."

[0071] Universal light chain: As used herein in the context of ABM, the term "universal heavy chain" refers to a light chain with a rearranged light chain variable region, for example, a human light chain with a rearranged Ig light chain variable region. Universal light chains are also known as "common heavy chains." In the context of ABM, they refer to a light chain polypeptide that can pair with the heavy chain regions of two different Fab domains with different variable regions in the same ABM. Universal light chains are also known as "common light chains." Exemplary rearranged Ig light chain variable regions are provided, for example, in U.S. Pat. Nos. 9,969,814, 10,130,181, and 10,143,186, and U.S. Patent Publication Nos. 2012 / 0021409, 2012 / 0192300, 2013 / 0045492, 2013 / 0185821, 2013 / 0302836, and 2015 / 0313193, each of which is incorporated by reference herein in its entirety.

[0072] VH: The term "VH" refers to the variable region of an immunoglobulin heavy chain of an antibody, including the heavy chain of a Fab.

[0073] VL: The term "VL" refers to the variable region of an immunoglobulin light chain, including the light chain of a Fab.

[0074] 6.2. Antigen binding molecules (ABM) Disclosed herein are antigen-binding molecules, such as monospecific and bispecific antigen-binding molecules.The disclosed antigen-binding molecules have binding domain arrangements that differ from typical antibody structures.The disclosed antigen-binding molecules can bind to a single target molecule or antigen with bispecificity, which can result in increased affinity and / or avidity for the antigen or target molecule.For example, for a bispecific antigen-binding molecule in which both Fabs bind to the same antigen with different epitopes, the affinity for the antigen would be expected to increase compared to an antibody that binds to only one of the epitopes.Without being bound by theory, it is believed that the ABMs disclosed herein have increased affinity for antigens or target molecules due to either increased proximity and / or greater flexibility of the Fab1 and Fab2 domains, which increases the local concentration of antigen-binding sites compared to conventional antibody formats in which the binding sites of the Fab domains are spaced apart.

[0075] In a first aspect, the ABM of the present disclosure comprises: In N-to-C-terminal orientation any hinge domain, a first Fc domain, and a first half antibody comprising a first Fab (Fab1) domain comprising a first heavy chain variable region (VH) associated with a first light chain variable region (VL); In N-to-C-terminal orientation any hinge domain, a second Fc domain, and a second half antibody comprising a second Fab domain ("Fab2") comprising a second VH associated with a second VL; The first Fc domain and the second Fc domain are associated with each other to form an Fc region, and the optional hinge domains, if present, may be associated with each other through disulfide bridges.

[0076] Two embodiments of this type of ABM, generally referred to herein as ABM format "A" ("Format A") and sometimes referred to herein as the "Fc-Fab" format, are illustrated in Figures 1B and 2B, and variations thereof shown in Figures 13A, 13B, and 13C. Accordingly, the present disclosure provides: In N-to-C-terminal orientation an optional hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, - an Fc domain comprising a CH2 domain (4) and a CH3 domain (5); an optional hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, - a linker (8), and - a Fab1 VH domain (1) and a Fab1 associated with the light chain component of the Fab1 domain. a first polypeptide comprising a heavy chain component of a Fab1 domain comprising a CH1 domain (2), and a light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab1 VL domain (6) and a Fab1 CL domain (7); In N-to-C-terminal orientation an optional hinge domain (3) linked via a disulfide bond to the hinge domain in the first polypeptide, - a second Fc domain comprising a CH2 domain (4) and a CH3 domain (5); an optional hinge domain (3) linked via a disulfide bond to the hinge domain in the first polypeptide, a linker (8), and - a second polypeptide comprising a heavy chain component of a Fab2 domain comprising a Fab2 VH domain (1) and a Fab2 CH1 domain (2) associated with a light chain component of a Fab2 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab2 VL domain (6) and a Fab2 CL domain (7); A Format A ABM is provided, as shown in Figures 1B and 2B, in which a first Fc domain and a second Fc domain associate with each other to form an Fc region.

[0077] In the embodiment of Figure 1B, both half antibodies are identical and contain Fc domains that form an Fc homodimer, and the resulting ABM is monospecific. In the embodiment of Figure 2B, the ABM contains an Fc heterodimer, allowing for the use of different Fab1 and Fab2 VH domains and the production of multispecific, e.g., bispecific, molecules. While Figures 1B, 2B, and 13A show embodiments in which the ABM has a hinge region composed of a hinge domain at the N-terminus of the Fc domain, Format A ABMs may not have a hinge region (not shown), a hinge region at the C-terminus of the Fc region (Figure 13C), or hinge regions at the N- and C-termini of the Fc region (Figure 13B). Exemplary hinge domains that can be used at the N- and / or C-termini of the Fc region include the amino acid sequences GGGGSCPPC (SEQ ID NO: 1) and ESKYGPPCPPC (SEQ ID NO: 2), as shown in Figures 13A-13C, although Format A ABMs may have alternative hinge region sequences. Similarly, Figures 13A to 13C show (G4S) n The linker is shown (G4S is disclosed as SEQ ID NO: 3), but other linker sequences can be used.

[0078] While Figures 1B and 2B show embodiments of a Format A ABM containing only two binding domains (Fab1 and Fab2), the ABMs of the present disclosure may contain additional binding domains, such as scFv or Fab domains. However, in certain aspects, Fab1 and Fab2 are the sole binding domains of a Format A ABM.

[0079] In a second aspect, the ABM of the present disclosure comprises: In N-to-C-terminal orientation a first Fab (Fab1) domain comprising a first VH associated with a first VL, a first spacer domain, and a first half antibody comprising a first Fc domain; and In N-to-C-terminal orientation a second Fab (Fab2) domain comprising a second VH associated with a second VL, a second spacer domain, and a second polypeptide comprising a second Fc domain, The first Fc domain and the second Fc domain associate with each other to form an Fc region.

[0080] Without being bound by theory, it is believed that the inclusion of a spacer domain between the Fc and Fab domains allows for greater flexibility between the Fc region and the antigen binding site of the Fab, and consequently, higher affinity and / or avidity of binding of the ABM to its target molecule.

[0081] In certain embodiments, the spacer domain is an extended linker. This ABM format, generally referred to herein as format "B" ("Format B") and sometimes referred to herein as the "reach" format, is illustrated in Figure 3A. Thus, the present disclosure provides: In N-to-C-terminal orientation - a heavy chain component of a Fab1 domain comprising a Fab1 VH domain (1) and a Fab1 CH1 domain (2) associated with a light chain component of a Fab1 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab1 VL domain (6) and a Fab1 CL domain (7); - a linker domain (8) which is an extended linker; a hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, and a first polypeptide comprising a first Fc domain comprising a CH2 domain (4) and a CH3 domain (5); In N-to-C-terminal orientation - a heavy chain component of a Fab2 domain comprising a Fab2 VH domain (1) and a Fab2 CH1 domain (2) associated with a light chain component of a Fab2 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab2 VL domain (6) and a Fab2 CL domain (7); - a linker domain (8) which is an extended linker; a hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, and and a second polypeptide comprising a second Fc domain comprising a CH2 domain (4) and a CH3 domain (5).

[0082] While the embodiment of Format B ABM shown in Figure 3A contains only two binding domains (Fab1 and Fab2), Format B ABMs of the present disclosure may contain additional binding domains, e.g., scFv or Fab domains. However, in certain aspects, Fab1 and Fab2 are the sole binding domains of Format B ABMs of the present disclosure.

[0083] In other embodiments, the spacer domain is a Fab domain. A different variation of this format ABM, referred to herein as format "C" ("Format C"), is illustrated in Figures 3B-3D. A Format C ABM thus comprises a third Fab (Fab3) domain and a fourth Fab (Fab4) domain, configured as follows: In N-to-C-terminal orientation a first Fab (Fab1) domain comprising a first VH associated with a first VL, a third Fab (Fab3) domain comprising a third VH associated with a third VL, and a first half antibody comprising a first Fc domain; and In N-to-C-terminal orientation a second Fab (Fab2) domain comprising a second VH associated with a second VL, a fourth Fab (Fab4) domain comprising a fourth VH associated with a fourth VL, and - a second half antibody comprising a second Fc domain.

[0084] Thus, the present disclosure: In N-to-C-terminal orientation - a heavy chain component of a Fab1 domain comprising a Fab1 VH domain (1) and a Fab1 CH1 domain (2) associated with a light chain component of a Fab1 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab1 VL domain (6) and a Fab1 CL domain (7); - linker domain (8), - a heavy chain component of a Fab3 domain comprising a Fab3 VH domain (1) and a Fab3 CH1 domain (2) associated with a light chain component of a Fab3 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab3 VL domain (6) and a Fab3 CL domain (7); a hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, and a first polypeptide comprising a first Fc domain comprising a CH2 domain (4) and a CH3 domain (5); In N-to-C-terminal orientation - a heavy chain component of a Fab2 domain comprising a Fab2 VH domain (1) and a Fab2 CH1 domain (2) associated with a light chain component of a Fab2 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab2 VL domain (6) and a Fab2 CL domain (7); - linker domain (8), - a heavy chain component of a Fab4 domain comprising a Fab4 VH domain (1) and a Fab4 CH1 domain (2) associated with a light chain component of a Fab4 domain, the light chain component in the form of a polypeptide comprising, in N- to C-terminal orientation, a Fab4 VL domain (6) and a Fab4 CL domain (7); a hinge domain (3) linked via a disulfide bond to a hinge domain in a second polypeptide, and and a second polypeptide comprising a second Fc domain comprising a CH2 domain (4) and a CH3 domain (5), wherein the first Fc domain and the second Fc domain associate with each other to form an Fc region.

[0085] While the embodiment of Format C ABM shown in Figures 3B-3D contains four binding domains (Fab1, Fab2, Fab3, and Fab4), Format C ABMs of the present disclosure may contain additional binding domains, e.g., scFv or Fab domains. However, in certain aspects, Fab1, Fab2, Fab3, and Fab4 are the sole binding domains of Format C ABMs of the present disclosure.

[0086] The Fab3 and Fab4 domains of Format C ABM can be non-binding (as shown in Figure 3B) or binding (as shown in Figures 3C and 3D). Those embodiments in which Fab3 and Fab4 are non-binding are generally referred to herein as Format C1 ABM, and this format may be referred to herein as the "clamp" format. Those embodiments in which Fab3 and Fab4 are binding are generally referred to herein as Format C2 ABM, and this format may be referred to herein as the "tandem Fab" format. The term "2+2 tandem Fab" refers to the embodiment shown in Figures 3C and 3D, in which Fab1, Fab2, Fab3, and Fab4 are the sole binding domains in the tandem Fab. Each of Format C1 and Format C2 ABM can be a homodimer or a heterodimer.

[0087] In certain embodiments of Format C1 ABM, the Fab1 and Fab2 domains are non-identical (e.g., bind to different epitopes, whether on the same or different target molecules), and the Fab3 and Fab4 domains are identical non-binding domains. In other embodiments, the Fab3 and Fab4 domains are different non-binding domains.

[0088] In a specific embodiment of format C2 ABM, the Fab1 and Fab3 domains comprise identical VH domains, and the Fab2 and Fab4 domains comprise identical VH domains, as shown in Figure 3C. This configuration is referred to as configuration 1, or 1-1-2-2 configuration. In an alternative embodiment of format C2 ABM, the Fab1 and Fab2 domains comprise identical VH domains, and the Fab3 and Fab4 domains comprise identical VH domains, as shown in Figure 3D. This configuration is referred to as configuration 2, or 1-2-1-2 configuration.

[0089] A complete ABM is formed by the association of two half antibodies through the two Fc domains that form the Fc region. If the two half antibodies are non-identical, for example, if Fab1 and Fab2 contain different VH domains, an Fc heterodimerization approach, such as that described in Section 6.2.7.2, can be utilized to facilitate correct half-antibody pairing or their purification. Examples of heterodimerization approaches are star mutations (described in Section 6.2.7.2) or knobs-in-holes mutations.

[0090] Although Figures 2B, 3A, 3B, and 3C show ABMs containing non-identical VH domains in each half antibody paired by an Fc heterodimer, this format can also be used for Fc homodimers. For example, Figures 2B and 3A show Format A and Format B ABMs, respectively, containing Fc heterodimers, but allow for the incorporation of different VH domains in Fab1 and Fab2 and the production of multispecific, e.g., bispecific, binding molecules. This format can also be used for Fc homodimers and monospecific Format A and Format B ABMs with identical VH domains. Similarly, Fc homodimers can be used to produce monospecific Format C ABMs with identical Fab1, Fab2, Fab3, and Fab4 VH domains, or identical Fab1 and Fab2 VH domains and non-binding Fab3 and Fab4 VH domains.

[0091] Furthermore, when the first and second polypeptides contain different VH domains, different strategies can be used to ensure correct VH-VL pairing in the multispecific binding molecule. For example, a common light chain can be used that can operably pair with two or more types of VH domains in the ABM. In such embodiments, the light chain polypeptides (e.g., Fab1 and Fab2, and, if present, the light chains associated with Fab3 and Fab4) can be identical. Alternatively, a single-domain Fab can be used in which the heavy chain components ((1) and (2)) can be expressed as a fusion with the light chain components ((6) and (7)).

[0092] The variations of the ABMs of the present disclosure shown in Figures 1-3 are not intended to be limiting, and the ABMs of the present disclosure can include any combination of the modifications shown in Figures 1-3 and in Section 6.2 below, among others. Additionally, reference to a first or second polypeptide chain or left or right half antibody is for convenience only and is not intended to convey that the polypeptide chains or half antibodies are produced or assembled in any particular order.

[0093] In some embodiments, the first Fab (Fab1) domain and the second Fab (Fab2) domain of an ABM of the present disclosure can each bind to the same target molecule, e.g., a small soluble molecule. The first Fab (Fab1) domain and the second Fab (Fab2) domain can bind to the same epitope (e.g., the embodiments shown in Figures 1B and 3D, or variations of Figures 3A or 3B, in which both Fab1 and Fab2 have identical VH domains (not shown)), or they can bind to different epitopes, whether on the same or different target molecules (e.g., the embodiments shown in Figures 2B, 3A, 3B, and 3C). When the first Fab (Fab1) domain and the second Fab (Fab2) domain bind to different epitopes, e.g., two different epitopes on the same or different target molecules, they can be selected so that the Fabs can simultaneously bind to those epitopes.

[0094] In some embodiments, for example, for Format C ABMs, the ABMs of the present disclosure can include a third Fab (Fab3) domain and a fourth Fab (Fab4) domain, as shown in Figures 3C, 3A, and 3D. The third and fourth Fab domains can be non-binding, as shown in Figure 3C, or they can bind to the same or different epitopes as those bound by the first and second Fab (Fab1 and Fab2) domains, respectively. As used herein, with respect to Format C ABMs, the terms "first and second Fab domains" and "Fab1 and Fab2 domains" typically refer to the most N-terminal Fab domains.

[0095] Certain target molecules, particularly those with repeated epitopes, such as those present in polypeptides with repeat motifs or proteins with multimeric structures (e.g., homodimers or homotrimers), can be bound by two or more antibody molecules, resulting in the formation of large complexes. The production of large, heterogeneous antibody complexes is referred to as "paper doring." Large antibody complexes can be rapidly eliminated by phagocytosis, resulting in reduced antibody efficacy. Large complexes can also increase the immunogenicity of therapeutic antibodies. See, for example, WO2020047067A1. The ABMs of the present disclosure may be less prone to aggregation, for example, in vivo or ex vivo, compared to the parent antibodies from which the Fab domains were derived. As a non-limiting example, for bispecific ABMs in which both Fabs bind to the same antigen with different epitopes, it was observed that the ABMs of the present disclosure primarily formed separate 1:1 complexes with the ligand, with little or no additional higher-order complexes, unlike results obtained with the parent mAb combination (see Example 4 below). In contrast, the parent mAb combinations formed multiple conformations (multimers), indicating that these parent antibodies formed multiple interligand bridges, e.g., forming unfolded "paper doll" structures. These results indicate that the ABMs disclosed herein are not prone to aggregation, likely because the proximity of the Fab domains favors the formation of 1:1 Fc-Fab ligand complexes relative to conformation. In practice, this may result in a higher relative concentration of a single ABM:target molecule complex than would be expected for the parent antibodies.

[0096] In some embodiments, the ABMs of the present disclosure specifically bind to at least two different epitopes (and in some cases three or four different epitopes), which may be on the same target molecule or different target molecules.

[0097] Fab Domain The ABMs of the present disclosure comprise at least one Fab domain in each half antibody. Fab domains are traditionally produced by proteolytic cleavage of immunoglobulin molecules using enzymes such as papain. In the ABMs of the present disclosure, the Fab domains are recombinantly expressed as part of a larger molecule.

[0098] The Fab domain can comprise constant and variable domain sequences from any suitable species, and thus can be murine, chimeric, human, or humanized.

[0099] The Fab domain typically comprises a CH1 domain attached to a VH domain, which is paired with a CL domain attached to a VL domain. In wild-type immunoglobulins, the VH domain is paired with the VL domain to form the Fv region, and the CH1 domain is paired with the CL domain to further stabilize the binding module. Disulfide bonds between the two constant domains can further stabilize the Fab domain.

[0100] For the ABMs of the present disclosure, particularly when the light chain is not a common or universal light chain, it is advantageous to use a Fab heterodimerization strategy to allow correct association of Fab domains belonging to the same ABS and minimize aberrant pairing of Fab domains belonging to different ABSs. For example, the Fab heterodimerization strategy shown in Table B below can be used. [Table 2]

[0101] Thus, in certain embodiments, correct association between the two polypeptides of a Fab is promoted by swapping the VL and VH domains of the Fab with one another, or by swapping the CH1 and CL domains with one another, as described, for example, in WO2009 / 080251.

[0102] Correct Fab pairing can also be promoted by introducing one or more amino acid modifications in the CH1 domain and one or more amino acid modifications in the CL domain of the Fab, and / or one or more amino acid modifications in the VH domain and one or more amino acid modifications in the VL domain. The modified amino acids are typically part of the VH:VL and CH1:CL interfaces, such that the Fab components preferentially pair with each other rather than with other Fab components.

[0103] In one embodiment, the one or more amino acid modifications are limited to conserved framework residues of the variable (VH, VL) and constant (CH1, CL) domains, as indicated by the Kabat numbering of the residues. Almagro, 2008, Frontiers In Bioscience 13:1619-1633 provides definitions of framework residues based on the Kabat, Chothia, and IMGT numbering schemes.

[0104] In one embodiment, the modifications introduced into the VH and CH1 and / or VL and CL domains are complementary to each other. Complementarity at the heavy and light chain interface can be achieved based on steric and hydrophobic contacts, electrostatic / charge interactions, or a combination of various interactions. Complementarity between protein surfaces has been widely described in the literature in terms of lock-and-key fit, knobs-into-holes, protrusions and cavities, donors and acceptors, etc., all of which refer to the nature of the structural and chemical match between two interacting surfaces.

[0105] In one embodiment, one or more of the introduced modifications introduce new hydrogen bonds across the interface of the Fab component. In one embodiment, one or more of the introduced modifications introduce new salt bridges across the interface of the Fab component. Exemplary substitutions are described in WO2014 / 150973 and WO2014 / 082179, the contents of which are incorporated herein by reference.

[0106] In some embodiments, the Fab domain comprises a 192E substitution in the CH1 domain and 114A and 137K substitutions in the CL domain, which introduce a salt bridge between the CH1 and CL domains (see, e.g., Golay et al., 2016, J Immunol 196:3199-211).

[0107] In some embodiments, the Fab domain comprises 143Q and 188V substitutions in the CH1 domain and 113T and 176V substitutions in the CL domain, which serve to exchange the hydrophobic and polar regions of contact between the CH1 and CL domains (see, e.g., Golay et al., 2016, J Immunol 196:3199-211).

[0108] In some embodiments, the Fab domain can include modifications in some or all of the VH, CH1, VL, and CL domains to introduce an orthogonal Fab interface that promotes correct assembly of the Fab domain (Lewis et al., 2014 Nature Biotechnology 32:191-198). In one embodiment, a 39K, 62E modification is introduced in the VH domain, an H172A, F174G modification is introduced in the CH1 domain, a 1R, 38D, (36F) modification is introduced in the VL domain, and an L135Y, S176W modification is introduced in the CL domain. In another embodiment, a 39Y modification is introduced in the VH domain and a 38R modification is introduced in the VL domain.

[0109] Fab domains can also be modified to replace the native CH1:CL disulfide bond with an engineered disulfide bond, thereby improving the efficiency of Fab moiety pairing. For example, an engineered disulfide bond can be introduced by introducing 126C into the CH1 domain and 121C into the CL domain (see, e.g., Mazor et al., 2015, MAbs 7:377-89).

[0110] Fab domains can also be modified by replacing the CH1 and CL domains with alternative domains that promote correct assembly. For example, Wu et al., 2015, MAbs 7:364-76, describe replacing the CH1 domain with a constant domain of a T cell receptor and the CL domain with a b domain of a T cell receptor, pairing these domain replacements with additional charge-charge interactions between the VL and VH domains by introducing a 38D modification in the VL domain and a 39K modification in the VH domain.

[0111] Alternatively, or in addition to using a Fab heterodimerization strategy to promote correct VH-VL pairing, a VL of a common light chain (also called a universal light chain) can be used in each Fab VL region of the ABM of the present disclosure. In various embodiments, using a common light chain as described herein reduces the number of incorrect species of the ABM compared to using the original cognate VL. In various embodiments, the VL domain of the ABM is identified from a monospecific antibody that includes a common light chain. In various embodiments, the VH region of the ABM comprises human heavy chain variable gene segments that are rearranged in vivo in mouse B cells previously engineered to express a limited human light chain repertoire, or a single human light chain cognate to a human heavy chain, to generate an antibody repertoire containing multiple human VHs that are cognate to one or one of two possible human VLs in response to exposure to an antigen of interest, the antibody repertoire being specific for the antigen of interest. The common light chain is derived from a rearranged human Vκ1-39Jκ5 sequence or a rearranged human Vκ3-20Jκ1 sequence, including somatically mutated (e.g., affinity matured) versions. See, e.g., U.S. Patent No. 10,412,940.

[0112] In some embodiments, the Fab is typically in the format of a single-chain Fab ("scFab"), comprising a VH, CH1, VL, CL, and a linker. In some embodiments, the domains of the scFab are arranged in the following order from N-terminus to C-terminus: a) VH-CH1-linker-VL-CL, b) VL-CL-linker-VH-CH1, c) VH-CL-linker-VL-CH1, or d) VL-CH1-linker-VH-CL. The linker may be a linker described in Section 6.2.3 and is preferably at least 30 amino acids long, and in certain embodiments, 32-50 amino acids long. The single-chain Fab domain is stabilized via a native disulfide bond between the CL and CH1 domains.

[0113] 6.2.2.scFv Single-chain Fv or "scFv" antibody fragments comprise the VH and VL domains of an antibody in a single polypeptide chain, can be expressed as single-chain polypeptides, and retain the specificity of the intact antibody from which they are derived. Generally, scFv polypeptides further comprise a polypeptide linker between the VH and VL domains that enables the scFv to form the desired structure for target binding. Examples of linkers suitable for connecting the VH and VL chains of scFvs are the linkers identified in Section 6.2.3.

[0114] Unless otherwise specified, as used herein, an scFv can have the VL and VH variable regions in either order, e.g., with respect to the N- and C-termini of the polypeptide, an scFv can comprise VL-linker-VH or VH-linker-VL.

[0115] The scFv can comprise VH and VL sequences from any suitable species, such as murine, human, or humanized VH and VL sequences.

[0116] To generate scFv-encoding nucleic acids, the VH- and VL-encoding DNA fragments are operably linked to another fragment encoding a linker, e.g., any of the linkers described in Section 6.2.3 (typically repeats of the amino acids glycine and serine, e.g., a sequence containing the amino acid sequence (Gly4 to Ser)3 (SEQ ID NO:4)), such that the VH and VL sequences can be expressed as a contiguous single-chain protein, the VL and VH regions joined by the flexible linker (see, e.g., Bird et al., 1988, Science 242:423-426; Huston et al., 1988, Proc. Natl. Acad. Sci. USA 85:5879-5883; McCafferty et al., 1990, Nature 348:552-554).

[0117] Linker In certain aspects, the present disclosure provides ABMs in which two or more domains (e.g., Fab and Fc regions) are connected to one another by a linker (or "spacer") peptide. Such linkers are referred to herein as "ABM linkers," in contrast to antibody-drug conjugate ("ADC") linkers used to attach drugs to ABMs, e.g., as described in Section 6.4.

[0118] Peptide linkers (e.g., polyglycine) are well known in the art and typically allow for proper folding of one or both components of a fusion protein. The linker provides a flexible junction region between the components of the fusion protein, allowing the two ends of the molecule to move independently and may play an important role in maintaining the proper function of each of the two parts. Thus, the junction region sometimes acts as a linker that joins the two parts together and as a spacer that allows each of the two parts to form its own biological structure and not interfere with the other part.

[0119] ABM linkers can range from 2 amino acids to 60 or more amino acids, and in certain embodiments, peptide linkers range in length from 3 amino acids to 50 amino acids, 4 to 30 amino acids, 5 to 25 amino acids, 10 to 25 amino acids, 10 to 60 amino acids, 12 to 20 amino acids, 20 to 50 amino acids, or 25 to 35 amino acids.

[0120] The present disclosure provides ABMs comprising a first polypeptide and a second polypeptide (e.g., the first and second polypeptides of the embodiments described in Section 6.2), each comprising a first linker and a second linker. The first linker and second linker may each comprise 0 to 60 or 0 to 50 amino acids, e.g., 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or The linker length can be 0-10, 5-15, 10-20, 15-25, 0-30, 5-30, 10-30, 20-30, 0-40, 5-40, 10-40, 15-40, 20-40, 25-40, 30-40, 35-40, 0-50, 5-50, 10-50, 15-50, 20-50, 25-50, 30-50, 35-50, 40-50, or 45-50 amino acids. For Fc-Fab, clamp, and tandem Fab format ABMs, the linker length is typically 5-30, e.g., 5-30 amino acid residues. For reach format ABMs, the linker length is typically 25-45, e.g., 30-40 amino acid residues.

[0121] Charged (e.g., charged hydrophilic linkers) and / or flexible linkers are particularly preferred. Examples of flexible linkers that can be used in the ABMs of the present disclosure include those disclosed in Chen et al., 2013, Adv Drug Deliv Rev. 65(10):1357-1369 and Klein et al., 2014, Protein Engineering, Design & Selection 27(10):325-330. Particularly useful flexible linkers are glycine and serine repeats, such as GnS or SGn monomers or multimers, where n is an integer from 1 to 18, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18. The most common of GnS or SGn is (G4S) n (G4S is disclosed as SEQ ID NO: 3) (i.e., (Gly4Ser) n or (Gly-Gly-Gly-Gly-Ser) n ) linker, and n indicates the number of repeats of the motif.

[0122] Extended linkers containing 4, 5, 6 or more repeats (e.g., 6, 7, 8, 9, or 10 or more repeats) of G4S (G4S is disclosed as SEQ ID NO: 3) and / or another flexible linker motif are particularly useful in reach formats, where the extended linker acts as a spacer that is thought to provide a more flexible bond resulting in greater affinity and / or avidity for small soluble molecules.

[0123] In some embodiments, the ABM linker is a polyglycine linker, such as Gly-Gly, Gly-Gly-Gly (3Gly), 4Gly (SEQ ID NO: 5), 5Gly (SEQ ID NO: 6), 6Gly (SEQ ID NO: 7), 7Gly (SEQ ID NO: 8), 8Gly (SEQ ID NO: 9), and 9Gly (SEQ ID NO: 10).

[0124] In other embodiments, the ABM linker is a glycine-serine linker. Examples of such linkers also include Ser-Gly, Gly-Ser, Gly-Gly-Ser, Ser-Gly-Gly, Gly-Gly-Gly-Ser (SEQ ID NO: 11), Ser-Gly-Gly-Gly (SEQ ID NO: 12), Gly-Gly-Gly-Gly-Ser (SEQ ID NO: 3), Ser-Gly-Gly-Gly-Gly (SEQ ID NO: 13), Gly-Gly-Gly-Gly-Gly-Ser (SEQ ID NO: 14), Ser-Gly-Gly-Gly-Gly-Gly (SEQ ID NO: 15), Gly-Gly-Gly-Gly-Gly-Gly-Ser (SEQ ID NO: 16), Ser-Gly-Gly-Gly-Gly-Gly-Gly (SEQ ID NO: 17), (Gly-Gly-Gly-Gly-Ser). n (G4S is disclosed as SEQ ID NO: 3), and (Ser-Gly-Gly-Gly-Gly) n (SG4 is disclosed as SEQ ID NO: 13), where n (number of repeats of the motif) = 1 to 10. (Gly-Gly-Gly-Gly-Ser) n (G4S is disclosed as SEQ ID NO: 3) and (Ser-Gly-Gly-Gly-Gly) n (SG4 is disclosed as SEQ ID NO: 13) also includes, respectively, (G4S) n and (SG4) nIn one embodiment, the peptide linker is (Gly-Gly-Gly-Gly-Ser)1 (SEQ ID NO: 3), (Gly-Gly-Gly-Gly-Ser)2 (SEQ ID NO: 18), (Gly-Gly-Gly-Gly-Ser)3 (SEQ ID NO: 4), or (Gly-Gly-Gly-Gly-Ser)4 (SEQ ID NO: 19). In some embodiments, the first linker and the second linker have the same amino acid sequence. In some embodiments, the polyglycine and serine amino acid sequence comprises two to six repeating GGGGS (SEQ ID NO: 3) amino acid sequences, e.g., two, three, four, five, or six repeating GGGGS (SEQ ID NO: 3) amino acid sequences. Extended linkers containing four, five, six, or more repeats (e.g., six, seven, eight, nine, or ten or more repeats) of any of the foregoing motifs are contemplated for reach formats.

[0125] 6.2.4. Hinge Area In other embodiments, the ABMs of the present disclosure comprise a hinge region, e.g., a hinge region composed of two hinge domains. The hinge can be used to connect the Fab domain to the Fc domain or to stabilize the ABM configuration.

[0126] The hinge region may be a native or modified hinge region. Hinge regions are typically found at the N-terminus of an Fc region, although in some embodiments, a hinge region may additionally or alternatively be found at the C-terminus of the Fc region of an ABM of the present disclosure, for example, in the Fc-Fab configurations shown in Figures 13B and 13C.

[0127] A native hinge region is the hinge region typically found between the Fab and Fc domains of naturally occurring antibodies. A modified hinge region is any hinge that differs in length and / or composition from the native hinge region. Such hinges can include hinge regions from other species, such as human, mouse, rat, rabbit, shark, pig, hamster, camel, llama, or goat hinge regions. Other modified hinge regions can include a complete hinge region derived from an antibody of a different class or subclass than that of the heavy chain Fc region. Alternatively, the modified hinge region can include a portion of a native hinge or repeating unit, with each unit in the repeat being derived from a native hinge region. In a further alternative, the native hinge region can be modified by converting one or more cysteine or other residues to neutral residues, such as serine or alanine, or by converting appropriately positioned residues to cysteine residues. By such means, the number of cysteine residues in the hinge region can be increased or decreased. Other modified hinge regions may be entirely synthetic and may be designed to have desired properties such as length, cysteine composition, and flexibility.

[0128] Several modified hinge regions have been previously described, for example, in U.S. Pat. No. 5,677,425, WO99 / 15549, WO2005 / 003170, WO2005 / 003169, WO2005 / 003170, WO98 / 25971, and WO2005 / 003171, which are incorporated herein by reference.

[0129] In various embodiments, positions 233-236 in the hinge domain can be G, G, G, and unoccupied; G, G, unoccupied, and unoccupied; G, unoccupied, unoccupied, unoccupied, and unoccupied; or all unoccupied, and the positions are numbered according to EU numbering.

[0130] In some embodiments, the ABMs of the disclosure comprise a modified hinge domain that reduces binding affinity for an Fcγ receptor compared to a wild-type hinge domain of the same isotype (e.g., human IgG1 or human IgG4).

[0131] In one embodiment, the Fc region of one or both chains of the ABM of this disclosure has an intact hinge domain at its N-terminus.

[0132] In one embodiment, both the Fc region and hinge region of the ABM of the present disclosure are derived from IgG4, with the hinge region containing the modified sequence CPPC (SEQ ID NO: 20). The core hinge region of human IgG4 contains the sequence CPSC (SEQ ID NO: 21), compared to IgG1, which contains the sequence CPPC (SEQ ID NO: 20). The serine residues present in the IgG4 sequence provide increased flexibility in this region, allowing a portion of the molecule to form disulfide bonds within the same protein chain (intrachain disulfides) rather than cross-linking to other heavy chains in an IgG molecule to form interchain disulfides (Angel et al., 1993, Mol Immunol 30(1):105-108). Changing the serine residues to prolines, resulting in the same core sequence as IgG1, allows for the complete formation of interchain disulfides in the IgG4 hinge region, thereby reducing heterogeneity in the purified product. This modified isotype is referred to as IgG4P.

[0133] 6.2.5. Chimeric Hinge Sequences The hinge region may be a chimeric hinge region.

[0134] For example, a chimeric hinge can comprise an "upper hinge" sequence derived from a human IgG1, human IgG2, or human IgG4 hinge region combined with a "lower hinge" sequence derived from a human IgG1, human IgG2, or human IgG4 hinge region.

[0135] In certain embodiments, the chimeric hinge region comprises the amino acid sequence EPKSCDKTHTCPPCPAPPVA (SEQ ID NO: 22) (previously disclosed as SEQ ID NO: 8 of WO2014 / 121087, which is incorporated by reference in its entirety) or ESKYGPPCPPCPAPPVA (SEQ ID NO: 23) (previously disclosed as SEQ ID NO: 9 of WO2014 / 121087). Such a chimeric hinge sequence may be suitably linked to an IgG4 CH2 region (e.g., by incorporation into an IgG4 Fc domain, e.g., a human or mouse Fc domain, which may be further modified in the CH2 and / or CH3 domains to reduce effector function, e.g., as described in Section 6.2.7.1).

[0136] 6.2.6. Hinge Sequences with Reduced Effector Function In further embodiments, the hinge region can be modified to reduce effector function, for example, as described in WO2016 / 161010A2, the entire contents of which are incorporated herein by reference. In various embodiments, positions 233-236 of the modified hinge region are G, G, G, and unoccupied; G, G, unoccupied, and unoccupied; G, unoccupied, unoccupied, unoccupied, and unoccupied; or all unoccupied, with positions numbered according to EU numbering (as shown in Figure 1 of WO2016161010A2). These segments can be represented as GGG-, GG-, G---, or ----, where "-" represents an unoccupied position.

[0137] Position 236 is unoccupied in standard human IgG2 but occupied in other standard human IgG isotypes. Positions 233-235 are occupied by residues other than G in all four human isotypes (as shown in Figure 1 of WO2016 / 161010A2).

[0138] Hinge modifications within positions 233-236 can be combined with position 228 being occupied by P. Position 228 is naturally occupied by P in human IgG1 and IgG2, but by S in human IgG4 and by R in human IgG3. The S228P mutation in IgG4 antibodies is advantageous for stabilizing IgG4 antibodies and reducing heavy-light chain pair exchange between exogenous and endogenous antibodies. Preferably, positions 226-229 are occupied by C, P, P, and C, respectively.

[0139] Exemplary hinge regions have residues 226-236, sometimes referred to as the middle (or core) and lower hinge, occupied by modified hinge sequences referred to as GGG-(233-236), GG--(233-236), G---(233-236), and no G(233-236). Optionally, the hinge domain amino acid sequence comprises CPPCPAPGGG-GPSVF (SEQ ID NO:24) (previously disclosed as SEQ ID NO:1 in WO2016 / 161010A2), CPPCPAPGG--GPSVF (SEQ ID NO:25) (previously disclosed as SEQ ID NO:2 in WO2016 / 161010A2), CPPCPAPG---GPSVF (SEQ ID NO:26) (previously disclosed as SEQ ID NO:3 in WO2016 / 161010A2), or CPPCPAP----GPSVF (SEQ ID NO:27) (previously disclosed as SEQ ID NO:4 in WO2016 / 161010A2).

[0140] The above-described modified hinge regions can be incorporated into heavy chain constant regions, which typically include CH2 and CH3 domains and may have additional hinge segments (e.g., upper hinges) flanking the designated regions. Such additional constant region segments are typically of the same isotype, preferably a human isotype, but may also be hybrids of different isotypes. The isotype of such additional human constant region segments is preferably human IgG4, but may also be human IgG1, IgG2, or IgG3, or hybrids thereof in which the domains are of different isotypes. Exemplary sequences of human IgG1, IgG2, and IgG4 are shown in Figures 2-4 of WO2016 / 161010A2.

[0141] In a specific embodiment, the modified hinge sequence can be linked to an IgG4 CH2 region (e.g., by incorporation into an IgG4 Fc domain, e.g., a human or mouse Fc domain, which can be further modified in the CH2 and / or CH3 domains to reduce effector function, e.g., as described in Section 6.2.7.1).

[0142] Fc Domain The ABMs of the present disclosure can comprise an Fc region derived from any suitable species, hi one embodiment, the Fc region is derived from a human Fc domain.

[0143] The Fc domain can be derived from any suitable class of antibody, including IgA (including subclasses IgA1 and IgA2), IgD, IgE, IgG (including subclasses IgG1, IgG2, IgG3, and IgG4), and IgM. In one embodiment, the Fc domain is derived from IgG1, IgG2, IgG3, or IgG4. In one embodiment, the Fc domain is derived from IgG1. In one embodiment, the Fc domain is derived from IgG4.

[0144] The two Fc domains within an Fc region can be the same as or different from one another. In natural antibodies, the Fc domains are typically identical, but for purposes of producing antigen-binding molecules, such as the ABMs of the present disclosure, the Fc domains can be advantageously different to allow for heterodimerization, as described in Section 6.2.7.2 below.

[0145] In natural antibodies, the heavy chain Fc domains of IgA, IgD, and IgG are composed of two heavy chain constant domains (CH2 and CH3), while the heavy chain Fc domains of IgE and IgM are composed of three heavy chain constant domains (CH2, CH3, and CH4), which dimerize to create the Fc region.

[0146] In the ABMs of the present disclosure, the Fc region, and / or Fc domains therein, can comprise heavy chain constant domains from one or more different classes of antibodies, for example, from one, two, or three different classes.

[0147] In one embodiment, the Fc region comprises CH2 and CH3 domains derived from IgG1.

[0148] In one embodiment, the Fc region comprises CH2 and CH3 domains derived from IgG2.

[0149] In one embodiment, the Fc region comprises CH2 and CH3 domains derived from IgG3.

[0150] In one embodiment, the Fc region comprises CH2 and CH3 domains derived from IgG4.

[0151] In one embodiment, the Fc region comprises a CH4 domain from IgM. The IgM CH4 domain is typically located C-terminal to the CH3 domain.

[0152] In one embodiment, the Fc region comprises the CH2 and CH3 domains derived from an IgG and the CH4 domain derived from an IgM.

[0153] It will be understood that heavy chain constant domains for use in producing Fc regions for ABMs of the present disclosure can include variants of the above-described naturally occurring constant domains. Such variants can include one or more amino acid variations compared to the wild-type constant domain. In one example, the Fc region of the present disclosure includes at least one constant domain that differs in sequence from the wild-type constant domain. It will be understood that the variant constant domain can be longer or shorter than the wild-type constant domain. Preferably, the variant constant domain is at least 60% identical or similar to the wild-type constant domain. In another example, the variant constant domain is at least 70% identical or similar. In another example, the variant constant domain is at least 80% identical or similar. In another example, the variant constant domain is at least 90% identical or similar. In another example, the variant constant domain is at least 95% identical or similar.

[0154] IgM and IgA naturally occur in humans as covalently linked multimers of a common H2L2 antibody unit. IgM occurs as a pentamer when a J chain is incorporated and as a hexamer when the J chain is absent. IgA occurs in both monomeric and dimeric forms. The heavy chains of IgM and IgA have an 18-amino acid extension to the C-terminal constant domain known as the tailpiece. The tailpiece contains cysteine residues that form disulfide bonds between heavy chains in the polymer and is thought to play an important role in polymerization. The tailpiece also contains glycosylation sites. In certain embodiments, the ABM of the present disclosure does not include a tailpiece.

[0155] The Fc domain incorporated into the ABMs of the present disclosure may include one or more modifications that alter the functional properties of the protein, for example, binding to an Fc receptor such as FcRn or a leukocyte receptor, binding to complement, modified disulfide bond structures, or altered glycosylation patterns. Exemplary Fc modifications that alter effector function are described in Section 6.2.7.1.

[0156] Fc domains can also be engineered to include modifications that improve the manufacturability of asymmetric ABMs, for example, by enabling heterodimerization, the preferential pairing of non-identical Fc domains with identical Fc domains. Heterodimerization allows for the production of ABMs in which different ABSs are connected to each other by Fc regions containing Fc domains that differ in sequence. Examples of heterodimerization strategies are illustrated in Section 6.2.7.2.

[0157] It will be appreciated that any of the above modifications can be combined in any suitable manner to achieve desired functional properties and / or combined with other modifications to alter the properties of the ABM.

[0158] 6.2.7.1. Fc Domains with Altered Effector Functions In some embodiments, the Fc domain comprises one or more amino acid substitutions that reduce binding to Fc receptors and / or effector functions.

[0159] In a specific embodiment, the Fc receptor is an Fcγ receptor. In one embodiment, the Fc receptor is a human Fc receptor. In one embodiment, the Fc receptor is an activating Fc receptor. In a specific embodiment, the Fc receptor is an activating human Fcγ receptor, more particularly human FcγRIIIa, FcγRI, or FcγRIIa, most particularly human FcγRIIIa. In one embodiment, the effector function is one or more selected from the group consisting of complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and cytokine secretion. In a specific embodiment, the effector function is ADCC.

[0160] In one embodiment, the Fc region comprises an amino acid substitution at a position selected from the group of E233, L234, L235, N297, P331, and P329 (numbering according to the Kabat EU index). In a more specific embodiment, the Fc region comprises an amino acid substitution at a position selected from the group of L234, L235, and P329 (numbering according to the Kabat EU index). In some embodiments, the Fc region comprises amino acid substitutions L234A and L235A (numbering according to the Kabat EU index). In one such embodiment, the Fc region is an Igd Fc region, particularly a human Igd Fc region. In one embodiment, the Fc region comprises an amino acid substitution at position P329. In a more specific embodiment, the amino acid substitution is P329A or P329G, particularly P329G (numbering according to the Kabat EU index). In one embodiment, the Fc region comprises an amino acid substitution at position P329 and an additional amino acid substitution at a position selected from E233, L234, L235, N297, and P331 (numbering according to the Kabat EU index). In a more specific embodiment, the additional amino acid substitution is E233P, L234A, L235A, L235E, N297A, N297D, or P331S. In a particular embodiment, the Fc region comprises amino acid substitutions at positions P329, L234, and L235 (numbering according to the Kabat EU index). In a more specific embodiment, the Fc region comprises amino acid mutations L234A, L235A, and P329G ("P329G LALA," "PGLALA," or "LALAPG").

[0161] Typically, the same one or more amino acid substitutions are present in each of the two Fc domains of the Fc region. Thus, in certain embodiments, each Fc domain of the Fc region comprises the amino acid substitutions L234A, L235A, and P329G (Kabat EU index numbering), i.e., in each of the first and second Fc domains in the Fc region, the leucine residue at position 234 is replaced with an alanine residue (L234A), the leucine residue at position 235 is replaced with an alanine residue (L235A), and the proline residue at position 329 is replaced with a glycine residue (P329G) (Kabat EU index numbering).

[0162] In one embodiment, the Fc domain is an IgG1 Fc domain, particularly a human IgG1 Fc domain. In some embodiments, the IgG1 Fc domain is a variant IgG1 containing D265A, N297A mutations (EU numbering) that reduce effector function.

[0163] In another embodiment, the Fc domain is an IgG4 Fc domain with reduced binding to Fc receptors. Exemplary IgG4 Fc domains with reduced binding to Fc receptors may comprise an amino acid sequence selected from Table C below. In some embodiments, the Fc domain comprises only the bolded portion of the sequence shown below: [Table 3-1] [Table 3-2] [Table 3-3] [Table 3-4]

[0164] In certain embodiments, the IgG4 with reduced effector function comprises the bolded portion of the amino acid sequence of SEQ ID NO: 31 of WO2014 / 121087 (corresponding to amino acids 99 to 326 of SEQ ID NO: 31 of the present application), and may be referred to herein as IgG4 or hIgG4.

[0165] For heterodimeric ABMs, it is possible to incorporate a combination of the variant IgG4 Fc sequences described above, for example an Fc region comprising a combination of SEQ ID NO: 30 of WO2014 / 121087 (or the bolded portion thereof corresponding to amino acids 99-329 of SEQ ID NO: 30 of the present application) and SEQ ID NO: 37 of WO2014 / 121087 (or the bolded portion thereof corresponding to amino acids 99-329 of SEQ ID NO: 32 of the present application), or an Fc region comprising a combination of SEQ ID NO: 31 of WO2014 / 121087 (or the bolded portion thereof corresponding to amino acids 99-326 of SEQ ID NO: 31 of the present application) and SEQ ID NO: 38 of WO2014 / 121087 (or the bolded portion thereof corresponding to amino acids 99-326 of SEQ ID NO: 33 of the present application).

[0166] Fc Heterodimerization Variants Unlike native immunoglobulins, many multispecific molecule formats involve dimerization between two Fc domains operably linked to non-identical antigen-binding domains (or portions thereof, e.g., VH or VH-CH1 of a Fab). Incorrect heterodimerization of the two Fc regions forming an Fc domain can be an obstacle to increasing the yield of the desired multispecific molecule and represents a purification challenge. Various approaches available in the art can be used to enhance the dimerization of Fc domains that may be present in the ABMs of the present disclosure, as described, for example, in EP 1870459 A1, U.S. Pat. No. 5,582,996, U.S. Pat. No. 5,731,168, U.S. Pat. No. 5,910,573, U.S. Pat. No. 5,932,448, U.S. Pat. No. 6,833,441, U.S. Pat. No. 7,183,076, U.S. Patent Application Publication No. 2006 / 204493 A1, and PCT Publication No. 2009 / 089004 A1.

[0167] The present disclosure provides ABMs comprising Fc heterodimers, i.e., Fc regions comprising heterologous, non-identical Fc domains. Heterodimerization strategies are used to enhance dimerization of Fc regions operably linked to different ABSs (or portions thereof, e.g., VH or VH-CH1 of Fabs) and reduce dimerization of Fc domains operably linked to the same ABS. Typically, each Fc domain in an Fc heterodimer comprises an antibody CH3 domain. The CH3 domain is derived from the constant region of an antibody of any isotype, class, or subclass, preferably the IgG (lgG1, lgG2, lgG3, and lgG4) class, as described in the previous section.

[0168] Heterodimerization of two different heavy chains at their CH3 domains will result in the desired ABM, whereas homodimerization of the same heavy chain will reduce the yield of the desired ABM. Thus, in preferred embodiments, the two half antibodies that associate to form the ABM of the present disclosure will contain CH3 domains with modifications that favor heterodimer association compared to unmodified chains.

[0169] In specific embodiments, the modification that promotes Fc heterodimer formation is a so-called "knob-into-hole" or "knob-in-hole" modification, which includes a "knob" modification in one of the Fc domains and a "hole" modification in the other Fc domain. Knob-into-hole technology is described, for example, in U.S. Pat. Nos. 5,731,168 and 7,695,936; Ridgway et al., 1996, Prot Eng 9:617-621; and Carter, 2001, Immunol Meth 248:7-15. Generally, the method involves introducing a protrusion ("knob") into the interface of a first polypeptide and a corresponding cavity ("hole") into the interface of a second polypeptide, where the protrusion can be positioned within the cavity to promote heterodimer formation and prevent homodimer formation. The protrusion is constructed by replacing a small amino acid side chain from the interface of the first polypeptide with a larger side chain (e.g., tyrosine or tryptophan). Compensatory cavities of identical or similar size to the protrusions are created at the interface of the second polypeptide by replacing large amino acid side chains with smaller ones (eg, alanine or threonine).

[0170] Thus, in some embodiments, an amino acid residue in the CH3 domain of a first subunit of an Fc domain is replaced with an amino acid residue having a larger side chain volume, thereby creating a protrusion in the CH3 domain of the first subunit that can be positioned within a cavity in the CH3 domain of a second subunit, and an amino acid residue in the CH3 domain of a second subunit of an Fc domain is replaced with an amino acid residue having a smaller side chain volume, thereby creating a cavity in the CH3 domain of the second subunit into which the protrusion in the CH3 domain of the first subunit can be positioned. Preferably, the amino acid residue having a larger side chain volume is selected from the group consisting of arginine (R), phenylalanine (F), tyrosine (Y), and tryptophan (W). Preferably, the amino acid residue having a smaller side chain volume is selected from the group consisting of alanine (A), serine (S), threonine (T), and valine (V). The protrusion and cavity can be created by altering the nucleic acid encoding the polypeptide, for example, by site-directed mutagenesis or by peptide synthesis. An exemplary substitution is Y470T.

[0171] In certain such embodiments, in the first Fc domain, the threonine residue at position 366 is replaced with a tryptophan residue (T366W), and in the Fc domain, the tyrosine residue at position 407 is replaced with a valine residue (Y407V), and optionally, the threonine residue at position 366 is replaced with a serine residue (T366S), and the leucine residue at position 368 is replaced with an alanine residue (L368A) (numbering according to the Kabat EU index). In a further embodiment, in the first Fc domain, additionally, the serine residue at position 354 is replaced with a cysteine residue (S354C) or the glutamic acid residue at position 356 is replaced with a cysteine residue (E356C) (particularly, the serine residue at position 354 is replaced with a cysteine residue), and in the second Fc domain, additionally, the tyrosine residue at position 349 is replaced with a cysteine residue (Y349C) (numbering according to the Kabat EU index). In a specific embodiment, the first Fc domain comprises amino acid substitutions S354C and T366W, and the second Fc domain comprises amino acid substitutions Y349C, T366S, L368A, and Y407V (numbering according to the Kabat EU index).

[0172] In some embodiments, electrostatic steering (e.g., as described in Gunasekaran et al., 2010, J Biol Chem 285(25):19637-46) can be used to promote association of the first and second subunits of the Fc domain.

[0173] Alternatively, or in addition to using an Fc domain modified to promote heterodimerization, the Fc domain can be modified to enable a purification strategy that allows for the selection of Fc heterodimers. In one such embodiment, one half antibody contains a modified Fc domain that abolishes its binding to Protein A, thereby enabling a purification method that results in a heterodimeric protein. See, e.g., U.S. Patent No. 8,586,713. As such, the ABM comprises a first CH3 domain and a second Ig CH3 domain, the first and second Ig CH3 domains differing from each other by at least one amino acid, the at least one amino acid difference reducing binding of the ABM to Protein A compared to a corresponding ABM lacking the amino acid difference. In one embodiment, the first CH3 domain binds to Protein A and the second CH3 domain contains a mutation / modification that reduces or eliminates Protein A binding, such as an H95R modification (according to IMGT exon numbering, H435R in EU numbering). The second CH3 may further comprise a Y96F modification (according to IMGT, Y436F in EU), thus a class of modifications referred to herein as "star" mutations.

[0174] 6.3.Target molecules The ABMs of the present disclosure comprise at least two Fab domains, Fab1 and Fab2, which each specifically bind to a target molecule, e.g., a small soluble molecule. In certain embodiments, the ABMs of the present disclosure further comprise two additional Fab domains, Fab3 and Fab4, which may be binding or non-binding. In some embodiments, the target molecules bound by the binding forms of Fab1, Fab2, and, if present, Fab3 and Fab4, are protein molecules.

[0175] Preferably, Fab1 and Fab2 are selected so that each can simultaneously specifically bind to its respective epitope. In some embodiments, Fab1 and Fab2 each specifically bind to different target molecules, for example, a pair of molecules that can interact with each other (such as a tumor-associated antigen and CD3). In other embodiments, Fab1 and Fab2 bind to the same target molecule, either to different epitopes or to the same epitope.

[0176] The ABMs of the present disclosure are believed to be particularly advantageous for binding to low molecular weight proteins, e.g., proteins having a molecular weight of less than 100 kDa, less than 75 kDa, or less than 60 kDa (with or without post-translational modifications such as glycosylation). In certain embodiments, proteins bound by the ABMs of the present disclosure have a molecular weight in the range of 5 kDa to 75 kDa, 5 kDa to 60 kDa, 5 kDa to 45 kDa, 5 kDa to 30 kDa, 10 kDa to 75 kDa, 10 kDa to 60 kDa, 10 kDa to 45 kDa, or 10 kDa to 30 kDa, in each case with or without post-translational modifications such as glycosylation.

[0177] Exemplary target molecules to which Fab1 and / or Fab2 can bind include ABCF1, ACVR1, ACVR1B, ACVR2, ACVR2B, ACVRLI, ADORA2A, aggrecan, AGR2, AICDA, AIF1, AIG1, AKAP1, AKAP2, AMH, AMHR2, ANGPT1, ANGPT2, ANGPTL3, ANGPTL4, ANPEP, APC, APOC1, AR, AZGP1 (zinc-α-glycoprotein), ART-4, B7, B7.1, B7.2, BAD, BAFF, BAGI, BAIi, BCL2, BCL6, B DNF, BLNK, BLRl (MDRlS), BlyS, BMPl, BMP2, BMP3B (GDF10), BMP4, BMP6, BMPS, BMPR1A, BMPR1B, BMPR2, BPAG1 (plectin), BRCA1, Ba-733, BAGE, BrE3-antigen, C A125, CAMEL, CAP-I, CASP-8 / m, CCCL19, CCCL21, CD1, CD1a, CD2, CD3, CD4, CDS, CD8, CDI-IA, CD14, CD15, CD16, CD18, CD19, CD20, CD21, CD22, CD23, CD25 , CD29, CD30, CD32b, CD33, CD37, CD38, CD40, CD40L, CD45, CD46, CD54, CD55, CD59, CD64, CD66a-e, CD67, CD70, CD74, CD79a, CD80, CD83, CD95, CD126, C D133, CD138, CD147, CD154, CDC27, CDK-4 / m, CDKN2A, CXCR4, CXCR7, CXCL12, C19orf10(IL27w), C3, C4A, CS, CSR1, CANT1, CASPI, CASP4, CAV1, CCBP2(D6 / JAB61), CCLI (I-309), CCLII (eotaxin), CCL13 (MCP-4), CCLIS (MIP-1d), CCL16 (HCC-4), CCL17 (TARC), CCLIS (PARC), CCL19 (MIP-3b), CCL2 (MCP-1), MCAF, CCL20 (MIP-3a), CCL21 (MIP-2), SLC, Exodus-2, CCL22 (MDC / STC-1), CCL23 (MPIF-1), CCL24 (MPIF-2 / eotaxin-2), CCL2S (TECK), CCL26 (eotaxin-3),CCL27(CTACK / ILC)、CCL2S、CCL3(MIP1a)、CCL4(MIP-1b)、CCLS(RANTES)、CCL7(MCP-3)、CCLS(mcp-2)、CCNA1、CCNA2、CCND1、CCNE1、CCNE2、CCR1(CKR1 / HM14S)、CCR2(mcp-1RB / RA)、CCR3(CKR3 / CMKBR3)、CCR4、CCRS(CMKBRSI ChemR13)、CCR6(CMKBR6 / CKR-L3 / STRL22 / DRY6)、CCR7(CKR7 / EB1)、CCRS(CMKBRS / TER1 / CKR-LI)、CCR9(GPR-9-6)、CCRLI(VSHK1)、CCRL2(L-CCR)、CD164、CDlC、CD200、CD-22、CD24、CD2S、CD3S、CD3E、CD3G、CD3Z、CD4、CD44、CD4SRB、CD47、CD4S、CDS2、CD69、CD72、CD79A、CD79B、CDSO、CDS1、CDS3、CDS6、CD137、CD13S、B7-1、B7-2、ICOSL、B7-H3、B7-H4、CD137L、OX40L、CDH1(E-カドヘリン)、CDH10、CDH12、CDH13、CDHlS、CDH19、CDH20、CDHS、CDH7、CDHS、CDH9、CDK2、CDK3、CDK4、CDKS、CDK6、CDK7、CDK9、CDKN1A(p21 Wap1 / Cip1)、CDKN1B(p27Kip1)、CDKN1C、CDKN2A(p16INK4a)、CDKN2B、CDKN2C、CDKN3、CEBPB、CER1、CHGA、CHGB、キチナーゼ、CHST1O、CKLFSF2、CKLFSF3、CKLFSF4、CKLFSFS、CKLFSF6、CKLFSF7、CKLFSFS、CLDN3、CLDN7(クローディン-7)、CLN3、CLU(クラステリン)、CMKLR1、CMKOR1(RDC1)、CNR1、COLISA1、COLIA1、COL4A3、COL6Al、CR2、CRP、CSF1(M-CSF)、CSF2(GM-CSF)、CSF3(GCSF)、CTLA-4、CTNNB1(b-カテニン)、CTSB(カテプシンB)、CX3CLI(SCYD1)、CX3CR1(V2S)、CXCLI(GRO1)、CXCLIO(IP-10)、CXCL11(I-TAC / IP-9), CXCL13, CXCL14, CXCL16, CXCL2(GR02), CXCL3(GR03), CXCLS(ENA-7S / LIX), CXCL6(GCP-2), CXCL9(MIG), CXCR3(GPR9 / CKR-L2) ), CXCR6 (TYMSTR / STRL33 / Bonzo), CYBS, CYC1, CYSLTR1, HIF-1-a, colon-specific antigen-p (CSAp), CEA (CEACAM5), CEACAM6, c-met, DAB2IP, DES, DKFZp4S1J011S, D NCLI, DPP4, DAM, EGFR, EGFRvlll, EGP-1, EGP-2, ELF2-M, Ep-CAM, E2F1, ECGF1, EDG1, EFNA1, EFNA3, EFNB2, EGF, EGFR, ELAC2, ENG, EN01, EN02, EN03, EP HB4, EPO, EREG, ERKS, ESR1, ESR2, F3(TF), FADD, FasL, FASN, FCER1A, FCER2, FCGR3A, FGF, FGF1(aFGF), FGF10, FGF11, FGF12, FGF12B, FGF13, FGF14, FG F16, FGF17, FGF1S, FGF19, FGF2 (bFGF), FGF20, FGF21, FGF22, FGF23, FGF3 (int-2), FGF4 (HST), FGFS, FGF7 (KGF), FGFS, FGF9, FGFR3, FIGF (VEGFD), FILI (EPSILON), FILI (ZETA), FLJ12SS4, FLJ2SS30, FLRT1 (fibronectin), FOS, FOSLI (FRA-1), FY (DARC), Flt-I, Flt-3, folate receptor, G250 antigen, GAGE, GROB, GABR P(GABAa), GAGEB1, GAGEC1, GALNAC4S-6ST, GATA3, GDFS, GFil, GGTl, GM-CSF, GNAS1, GNRH1, GPR2(CCR10), GPR31, GPR44, GPRS1(FKSGSO), GRCC10(C10), GRP, GSN(gelsolin), GSTP1, HAVCR2, HDAC4, HDACS, HDAC7A, HDAC9, HGF, HIP1 histamine and histamine receptor, HLA-A, HLA-DRA, HM74, HMOX1, HUMCYT2A, HLA-DR, HMI 24,Human chorionic gonadotropin (HCG) and its subunits, HER2 / neu, HMGB-1, hypoxia-inducible factor (HIF-1), HSP70-2M, HST-2 or 1a, IGF-IR,

number

[0178] In some embodiments, the ABMs of the present disclosure can bind to pairs of target molecules, for example, via Fab1 and Fab2. Exemplary pairs of target molecules include CD137 and CD20, CD137 and EGFR, CD137 and Her-2, CD137 and PD-1, CD137 and PDL-1, VEGF and PD-L1, Lag-3 and TIM-3, OX40 and PD-1, TIM-3 and PD-1, TIM-3 and PDL-1, EGFR and DLL-4, CD138 and CD20, CD138 and CD40, CD19 and CD20, CD20 and CD3, CD3 and CD33, CD3 and CD133, CD47 and CD20, CD38 and CD138, CD38 and CD20, CD20 and CD22, CD38 and CD40, CD40 and CD20, CD-8 and IL-6, CSPGs and RGM-1. A, CTLA-4 and BTN02, IGF1 and IGF2, IGF1 / 2 and Erb2B, IGF-1R and EGFR, EGFR and CD13, IGF-1R and ErbB3, EGFR-2 and IGFR, VEGFR-2 and Met, VEGF-A and angiopoietin-2 (Ang-2), IL-12 and TWEAK, IL-13 and IL-1beta, PDGFR and VEGF, EpCAM and CD3, Her2 and CD3, CD19 and CD3, EGFR and Her3, CD16a and CD30, CD30 and PSMA, EGFR and CD3, CEA and CD3, TROP-2 and HSG, TROP-2 and CD3, MAG and RGM-A, NgR and RGM-A, NogoA and RGM-A, OMG and RGM-A A, PDL-1 and CTLA-4, CTLA-4 and PD-1, PD-1 and TIM-3, RGMA and RGM B, Te38 and TNFa, TNFa and Blys, TNFa and CD-22, TNFa and CTLA-4 domain, TNFa and GP130, TNFa and IL-12p40, and TNFa and RANK ligand.

[0179] In some embodiments, the ABM of the present disclosure can bind to one or more cytokines, cytokine-related proteins, and / or cytokine receptors, e.g., one or a pair of cytokines, cytokine-related proteins, and / or cytokine receptors, e.g., via Fab1 and Fab2. Exemplary cytokines, cytokine-related proteins, and / or cytokine receptors include BMP1, BMP2, BMP3B (GDF10), BMP4, BMP6, BMP8, CSF1 (M-CSF), CSF2 (GM-CSF), CSF3 (G-CSF), EPO, FGF1 (aFGF), FGF2 (bFGF), FGF3 (int-2), FGF4 (HST), FGF5, FGF6 (HST-2), FGF7 (KGF), FGF9, FGF10, FGF11, FGF12, FGF13, FGF14, FGF15, FGF16, FGF17, FGF18, FGF19, FGF20, FGF21, FGF22, FGF23, FGF24, FGF25, FGF26, FGF27, FGF28, FGF29, FGF30, FGF31, FGF32, FGF33, FGF34, FGF35, FGF36, FGF37, FGF38, FGF39, FGF40, FGF41, FGF42, FGF43, FGF44, FGF45, FGF46, FGF47, FGF48, FGF49, FGF50, FGF51, FGF52, FGF53, FGF54, FGF55, FGF56, FGF57, FGF58, FGF59, FGF59, FGF510, FGF511, FGF512, FGF513, FGF514, FGF515, FGF516, FGF517, FGF5 GF12, FGF12B, FGF14, FGF16, FGF17, FGF19, FGF20, FGF21, FGF23, IGF1, IGF2, IFNA1, IFNA2, IFNA4, IFNA5, IFNA6, IFNA7, IFNB1 , IFNG, IFNW1, FILI, FILI(EPSILON), FILI(ZETA), ILIA, ILIB, IL2, IL3, IL4, IL5, IL6, IL7, IL8, IL9, ILIO, ILi1, ILI2A, ILI2B, ILI3, ILI4, ILI5, ILI6, ILI7, ILI7B, ILI8, ILI9, IL20, IL22, IL23, IL24, IL25, IL26, IL27, IL28A, IL28B, IL29, IL30, PDGFA, F GER1, FGFR2, FGFR3, EGFR, RORI, 2B4, KIR, CD137, CD27, OX40, CD40L, A2aR, CD48, B7-1, B7-2, ICOSL, B7-H3, B7-H4, CD137L, OX40 L, CD70, CD40, PDGFB, TGFA, TGFB1, TGFB2, TGFB3, LTA (TNF-b), LTB, TNF (TNF-a), TNFSF4 (OX40 ligand), TNFSF5 (CD40 ligand), TNFSF6 (FasL), TNFSF7 (CD27 ligand), TNFSF8 (CD30 ligand), TNFSF9 (4-1BB ligand), TNFSF10 (TRAIL), TNFSF11 (TRANCE), TNFSF12 (AP03L),TNFSF13(April), TNFSF13B, TNFSF14(HVEM-L), TNFSF15(VEGI), TNFSF18, FIGF(VEGFD), VEGF. VEGFB, ILIR2, ILIRLI, IL2RA, IL2RB, IL2RG, IL3RA, IL4R, IL5RA, IL6R, IL 7R, IL8RA, IL8RB, IL9R, ILIORA, ILIORB, IL11RA, ILI2RB1, ILI2RB2, ILI3RA1, ILI3RA2, ILI5RA, ILI7R, ILI8R1, IL20RA, IL21R L22R, IL1HY1, ILIRAP, ILIRAPLI, ILIRAPL2, ILIRN, IL6ST, ILI8 BP, ILI8RAP, IL22RA2, AIF1, HGF, LEP(protein), PTN, THPO, etc.

[0180] In some embodiments, the ABMs of the present disclosure can bind to one or more chemokines, chemokine-related proteins, and / or chemokine receptors, e.g., one or a pair of chemokines, chemokine-related proteins, and / or chemokine receptors, e.g., via Fab1 and Fab2. Exemplary chemokines, chemokine-related proteins, and chemokine receptors include CCLI (I-309), CCL2 (MCP-1 / MCAF), CCL3 (MIP1a), CCL4 (MIP-1b), CCL5 (RANTES), CCL7 (MCP-3), CCL8 (mcp-2), CCLII (eotaxin), CCLI3 (MCP-4), CCLI5 (MIP-1 d), CCLI 6 (HCC-4), CCLI 7 (TARC), CCLI 8 (TARC), CCLI 9 (TARC), CCLI 10 (TARC), CCLI 11 (TARC), CCLI 12 (TARC), CCLI 13 (MCP-4), CCLI 14 (MCP-1), CCLI 15 (MCP-1), CCLI 16 (MCP-1), CCLI 17 (MCP-1), CCLI 18 (MCP-1), CCLI 19 (MCP-1), CCLI 20 (MCP-1), CCLI 21 (MCP-1), CCLI 22 (MCP-1), CCLI 23 (MCP-1), CCLI 24 (MCP-1), CCLI 25 (MCP-1), CCLI 26 (MCP-1), CCLI 27 (MCP-1), CCLI 28 (MCP-1), CCLI 29 (MCP-1), CCLI 30 (MCP-1), CCLI 31 (MCP-1), CCLI 32 (MCP-1), CCLI 33 (MCP-1), CCLI 34 (MCP-1), CC 8(PARC), CCLI9(MIP-3b), CCL20(MIP-3a), CCL21(SLC / Exodus-2), CCL22(MDC / STC-1), CCL23(MPIF-1), CCL24(MPIF-2 / Eotaxin-2), CCL25(TECK), CCL26 (eotaxin-3), CCL27 (CTACK / ILC), CCL28, CXCLI (GRO1), CXCL2 (GR02), CXCL3 (GR03), CXCL5 (ENA-78), CXCL6 (GCP-2), CXCL9 (MIG), CXCLIO (IP10) CXCL11(I-TAC), CXCL12(SDF1), CXCL13, CXCL14, CXCL16, PF4(CXCL4), PPBP(CXCL7), CX3CL1(SCYD). 1) SCYE1, XCL1(ツシ), XCL2(SCM-1b), BLR1(MDR15), CCBP2(D6 / JAB61), CCR1(CKR1 / HM145), CCR2(m cp-1RB / RA) CCR3(CKR3 / CMKBR3), CCR4, CCR5(CMKBR5 / ChemR13), CCR6(CMKBR6 / CKR-L3 / STRL22 / DRY6); CCR7(CKR7 / EBI1), CCRS(CMKBR8 / TER1 / CKR-L1), CCR9(GPR-9-6), CCRL1(VSHK1), CCRL2(L-CCR), XCR1(G). PR5 / CCXCR1) CMKLR1 CMKOR1(RDC1) CX3CR1(V28) CXCR4 GPR2(CCR10) GPR31 GPR81(FKSGSO) CXCR 3(GPR9 / CKR-L2), CXCR6(TYMSTR / STRL33 / Bonzo), HM74, ILSRA(IL8Ra), ILSRB(IL8Rb), LTB4R(GPR16),T CP10, CKLFSF2, CKLFSF3, CKLFSF4, CKLFSF5, CKLFSF6, CKLFSF7, CKLFSFS, BDNF, C5R1, CSF3, GRCC10(C10) EPO, FY(DARC), GDF5, HIF1A, ILS, PRL, RGS3, RGS13, SDF2, SLIT2, TLR2, TLR4, TREM1, TREM2, and VHL.

[0181] In some embodiments, the ABMs of the present disclosure can bind to cytokine pairs, cytokine receptors, and / or cytokine-related proteins. Exemplary cytokine pairs include IL-1α and IL-1β, IL-12 and IL-18, TNFα and IL-23, TNFα and IL-13, TNF and IL-18, TNF and IL-12, TNF and IL-1 beta, TNF and MIF, TNF and IL-6, TNF and IL-6 receptor, TNF and IL-17, IL-17 and IL-20, IL-17 and IL-23, TNF and IL-15, and TNF and VEGF. , VEGFR and EGFR, PDGFR and VEGF, IL-13 and IL-9, IL-13 and IL-4, IL-13 and IL-5, IL-13 and IL-25, IL-13 and TARC, IL-13 and MDC, IL-13 and MIF, IL-13 and TGF-β, IL-13 and LHR agonist, IL-13 and CL25, IL-13 and SPRR2a, IL-13 and SPRR2b, IL-13 and ADAM 8, and TNFa and PGE4, IL-13 and PED2, and TNF and PEG2.

[0182] In some embodiments, the ABMs of the present disclosure are capable of binding to at least two epitopes on a single cytokine, cytokine receptor, or cytokine-related protein. Exemplary cytokines include TSLP, IL-1α, IL-Ιβ, IL-12, IL-18, TNFα, IL-23, IL-13, MIF, IL-6, IL-6 receptor, IL-17, IL-20, IL-15, VEGF, VEGFR, EGFR, PDGFR, IL-9, IL-4, IL-5, IL-25, TARC, MDC, TGF-β, LHR agonist, CL25, SPRR2α, SPRR2b, ADAM 8, PGE4, PED2, and PEG2.

[0183] In some embodiments, the ABMs of the present disclosure can bind to their antigen targets with similar or greater affinity compared to antibodies or antibody fragments in conventional formats.

[0184] In some embodiments, the ABMs of the present disclosure have agonist function with respect to their target molecule, hi other embodiments, the ABMs of the present disclosure have blocking and / or antagonist function with respect to their antigen or target molecule.

[0185] In certain embodiments, the ABMs of the present disclosure have similar or lower IC compared to, for example, traditional IgG formats from which the Fab of the ABM is derived. 50 a similar or lower IC for that antigen or target molecule compared to a parent antibody (or pair of parent antibodies), such as a parent IgG1, IgG2, IgG3, IgG4, IgD, IgA, IgE, or IgM antibody 50 It has.

[0186] In some embodiments, the ABMs of the present disclosure are bispecific for a single ligand and form 1:1 ligand complexes at a higher level compared to the parent antibody(ies).

[0187] When Fab1 and Fab2 bind to different epitopes on the same target molecule, binding to the target molecule is preferably non-competitive, i.e., Fab1 and Fab2 do not compete for binding to the target molecule (as may occur, for example, if the epitopes overlap). Assays for measuring binding competition between antibodies and antibody fragments are known in the art and include, for example, enzyme-linked immunosorbent assays (ELISAs), fluorescence-activated cell sorting (FACS) assays, and surface plasmon resonance assays.

[0188] Competition for binding to target molecules can be determined, for example, using a real-time, label-free biolayer interference assay on the Octet HTX biosensor platform (Pall ForteBio Corp.). In a specific embodiment of the assay, the entire assay is performed in a buffer solution of 10 mM HEPES, 150 mM NaCl, 3 mM EDTA, 1 mg / mL BSA, 0.05% v / v surfactant Tween-20, pH 7.4 (HBS-EBT buffer) at 25° C. with the plate shaking at a speed of 1000 rpm. To assess whether two antibodies or antigen-binding fragments thereof can compete with each other for binding to their respective epitopes on their specific target antigens, a penta-His-tagged target antigen ("penta-His" is disclosed as SEQ ID NO: 34) is first captured onto an Octet biosensor chip (Fortebio Inc, #18-5122) coated with an anti-penta-His antibody ("penta-His" is disclosed as SEQ ID NO: 34) by immersing the biosensor chip into a well containing the penta-His-tagged target antigen ("penta-His" is disclosed as SEQ ID NO: 34). The antigen-captured biosensor chip is then saturated with a first antibody or antigen-binding fragment thereof (hereafter referred to as Ab-1) by immersion in a well containing a solution of Ab-1 (e.g., a 50 μg / mL solution). The biosensor chip is then subsequently immersed in a well containing a solution of a second antibody or antigen-binding fragment thereof (hereafter referred to as Ab-2) (e.g., a 50 μg / mL solution). The biosensor chip is washed with HBS-EBT buffer between every step of the assay. Real-time binding responses can be monitored throughout the entire course of the assay, and the binding responses at the end of every step can be recorded. The responses of Ab-2 binding to Ab-1 and pre-complexed target antigens can be compared, allowing the competitive / non-competitive behavior of different antibodies / antigen-binding fragments against the same target antigen to be determined.

[0189] In various embodiments, The ABM (e.g., Format A ABM or Format B ABM) does not contain Fab3 and Fab4, and Fab1 and Fab2 bind to the same or different epitopes on the same target molecule; the ABM (e.g., Format A ABM or Format B ABM) does not contain Fab3 and Fab4, and Fab1 and Fab2 bind to different target molecules; The ABM (e.g., Format C ABM) comprises a non-binding Fab3 and a non-binding Fab4, and Fab1 and Fab2 bind to the same or different epitopes on the same target molecule; the ABM (e.g., Format C ABM) comprises a non-binding Fab3 and a non-binding Fab4, and Fab1 and Fab2 bind to different target molecules; the ABM (e.g., Format C ABM) comprises a binding Fab3 and a binding Fab4, wherein Fab1 and Fab2 bind to the same epitope, and Fab3 and Fab4 bind to the same epitope, different from the epitope bound by Fab1 and Fab2, either on the same or a different target molecule as the target molecule bound by Fab1 and Fab2; An ABM (e.g., Format C ABM) comprises a binding Fab3 and a binding Fab4, wherein Fab1 and Fab3 bind to the same epitope, and Fab2 and Fab4 bind to the same epitope, different from the epitope bound by Fab1 and Fab3, either on the same or a different target molecule as the target molecule bound by Fab1 and Fab3.

[0190] When two or more of Fab1, Fab2, Fab3, and Fab4 bind to the same epitope on a target molecule, such Fab domains can have the same or different heavy chain CDR sequences and / or the same or different VH sequences. Optionally, they can have the same or different VL sequences.

[0191] Without being bound by theory, it is believed that the ABMs of the present disclosure have the advantage of binding to target molecules with greater affinity than parent monospecific or bispecific antibodies with their native configuration. Thus, the ABMs of the present disclosure, in some embodiments, can bind to one or more target molecules with greater affinity than parent monospecific or bispecific antibodies with their native configuration. For example, the ABMs, in some embodiments, have a lower K for binding to a target molecule in a cell-based binding assay (e.g., as described in Section 7) than the corresponding parent monospecific or bispecific antibody. D and / or may have a more potent EC50 value.

[0192] The agonist or antagonist activity of a given antibody or ABM depends on target selection, epitope coverage, and format selection. Identification of agonist and antagonist antibodies can be achieved, for example, through function-based screening. The ABM format of the present disclosure is particularly advantageous for antagonist activity against small soluble molecules.

[0193] 6.4. Antibody Drug Conjugates The ABMs of the present disclosure can be conjugated to a drug moiety, for example, via a linker, particularly when the ABM is intended for use as a cancer therapeutic. For convenience, such conjugates are referred to herein as antibody-drug conjugates (or "ADCs").

[0194] In certain aspects, the drug moiety exerts cytotoxic or cytostatic activity. In one embodiment, the drug moiety is selected from the group consisting of maytansinoids, kinesin-like protein KIF11 inhibitors, V-ATPase (vacuolar H+-ATPase) inhibitors, pro-apoptotic agents, Bcl2 (B-cell lymphoma 2) inhibitors, MCL1 (myeloid cell leukemia 1) inhibitors, HSP90 (heat shock protein 90) inhibitors, IAP (inhibitors of apoptosis) inhibitors, mTOR (mechanistic target of rapamycin) inhibitors, microtubule stabilizers, microtubule destabilizers, auristatins, dolastatins, MetAP (methionine aminopeptidase), CRM1 (chromosome maintenance 1) inhibitors. , DPPIV (dipeptidyl peptidase IV) inhibitors, proteasome inhibitors, inhibitors of mitochondrial phosphoryl transfer reactions, protein synthesis inhibitors, kinase inhibitors, CDK2 (cyclin-dependent kinase 2) inhibitors, CDK9 (cyclin-dependent kinase 9) inhibitors, kinesin inhibitors, HDAC (histone deacetylase) inhibitors, DNA damaging agents, DNA alkylating agents, DNA intercalators, DNA minor groove binders, RNA polymerase inhibitors, topoisomerase inhibitors, or DHFR (dihydrofolate reductase) inhibitors.

[0195] In some embodiments, the cytotoxic agent is a maytansinoid having the following structure: [ka]

[0196] In some embodiments, the cytotoxic agent is a maytansinoid having the following structure: [ka]

[0197] In some embodiments, the ADC comprises an ABM of the present disclosure, [ka] [ka] is the binding to the ABM.

[0198] In some embodiments, the antibody-drug conjugate comprises an ABM of the present disclosure, [ka]

[0199] [ka] is the binding to the ABM.

[0200] In some embodiments, the ADC comprises an ABM of the present disclosure and [ka] ,or [ka] ,or including mixtures thereof, [ka] is the binding to the ABM of the present disclosure.

[0201] In some embodiments, the bond is linked to the ABM via the sulfur moiety of a cysteine residue.

[0202] In some embodiments, the bond is linked to the ABM via the nitrogen moiety of a lysine residue.

[0203] In the ADCs of the present disclosure, the cytotoxic and / or cytostatic agent is linked to the ABM by an ADC linker. The ADC linker linking the cytotoxic and / or cytostatic agent to the ABM of the ADC can be short, long, hydrophobic, hydrophilic, flexible, or rigid, or can be composed of segments each independently having one or more of the above properties, so that the linker can contain segments with different properties. The linkers can be multivalent, covalently linking two or more agents to a single site on the ABM, or monovalent, covalently linking a single agent to a single site on the ABM.

[0204] In certain aspects, the linker is selected from a cleavable linker, a non-cleavable linker, a hydrophilic linker, a pro-charged linker, or a dicarboxylic acid-based linker.

[0205] As will be appreciated by those skilled in the art, the ADC linker links the cytotoxic and / or cytostatic agent to the ABM by forming a covalent linkage to the cytotoxic and / or cytostatic agent at one location and a covalent linkage to the ABM at another location, where the covalent linkages are formed by reaction between functional groups on the ADC linker and functional groups on the drug and ABM.

[0206] The ADC linker is preferably chemically stable to extracellular conditions, but need not be; it can be designed to cleave, break, and / or otherwise specifically degrade intracellularly. Alternatively, an ADC linker that is not designed to specifically cleave or degrade intracellularly can be used. The choice of stable versus unstable ADC linker can depend on the toxicity of the cytotoxic and / or cytostatic agent. For drugs that are toxic to normal cells, a stable linker is preferred. Selective or targeted drugs with lower toxicity to normal cells can be utilized, in which the chemical stability of the ADC linker to the extracellular environment is less important. A wide variety of ADC linkers useful for linking drugs to ABMs in the context of ADCs are known in the art. Any of these and other ADC linkers can be used to link cytotoxic and / or cytostatic agents to the ABM of the ADCs of the present disclosure.

[0207] Exemplary multivalent ADC linkers that can be used to link multiple cytotoxic and / or cytostatic agents to a single ABM molecule are described, for example, in WO2009 / 073445, WO2010 / 068795, WO2010 / 138719, WO2011 / 120053, WO2011 / 171020, WO2013 / 096901, WO2014 / 008375, WO2014 / 093379, WO2014 / 093394, and WO2014 / 093640, the contents of which are incorporated herein by reference in their entireties. For example, the Fleximer linker technology developed by Mersana et al. has the potential to enable high-DAR ADCs with favorable physicochemical properties. The Mersana technology is based on incorporating drug molecules into a solubilizing polyacetal backbone via a series of ester bonds. The methodology affords highly loaded ADCs (DAR up to 20) while maintaining good physicochemical properties.

[0208] Exemplary monovalent ADC linkers that can be used are described, for example, in Nolting, 2013, Antibody-Drug Conjugates, Methods in Molecular Biology 1045:71-100; Ducrry et al., 2010, Bioconjugate Chem. 21:5-13; Zhao et al., 2011, J. Med. Chem. 54:3606-3623; U.S. Patent No. 7,223,837; U.S. Patent No. 8,568,728; U.S. Patent No. 8,535,678; and WO2004 / 010957, each of which is incorporated herein by reference.

[0209] By way of example and not limitation, some cleavable and non-cleavable ADC linkers that can be included in the ADCs of the present disclosure are listed below.

[0210] In certain embodiments, the selected ADC linker is cleavable in vivo. Cleavable ADC linkers may contain chemically or enzymatically unstable or degradable linkages. Cleavable ADC linkers generally rely on intracellular processes to release the drug, such as reduction in the cytoplasm, exposure to acidic conditions in lysosomes, or cleavage by specific proteases or other enzymes within the cell. Cleavable ADC linkers generally incorporate one or more chemical bonds that are cleavable either chemically or enzymatically, while the remainder of the ADC linker is non-cleavable. In certain embodiments, the ADC linker contains a chemically labile group such as a hydrazone and / or disulfide group. Linkers containing chemically labile groups take advantage of the different properties between plasma and some cytoplasmic compartments. The intracellular conditions that promote drug release for hydrazone-containing ADC linkers are the acidic environment of endosomes and lysosomes, while disulfide-containing ADC linkers are reduced in the cytosol, which contains high thiol concentrations, such as glutathione. In certain embodiments, the phenotypic stability of ADC linkers containing chemically labile groups can be increased by introducing steric hindrance using substituents near the chemically labile group.

[0211] A cleavable ADC linker may contain a non-cleavable moiety or segment, and / or a cleavable segment or moiety may be included in an otherwise non-cleavable ADC linker to render it cleavable. By way of example only, polyethylene glycol (PEG) and related polymers may contain cleavable groups in the polymer backbone. For example, a polyethylene glycol or polymer ADC linker may contain one or more cleavable groups, such as a disulfide, hydrazone, or dipeptide.

[0212] Other degradable linkages that can be included in ADC linkers include ester linkages formed by the reaction of PEG carboxylic acid or activated PEG carboxylic acid with an alcohol group on a biologically active agent; such ester groups generally hydrolyze under physiological conditions to release the biologically active agent. Hydrolytically degradable linkages include, but are not limited to, carbonate linkages; imine linkages resulting from the reaction of amines and aldehydes; phosphate ester linkages formed by reacting alcohols with phosphate groups; acetal linkages, which are the reaction products of aldehydes and alcohols; orthoester linkages, which are the reaction products of formates and alcohols; and oligonucleotide linkages formed by phosphoramidite groups, including, but not limited to, the termini of polymers and the 5' hydroxyl group of oligonucleotides.

[0213] In certain embodiments, the ADC linker comprises an enzymatically cleavable peptide moiety, e.g., a tripeptide or dipeptide. In certain embodiments, the dipeptide is selected from Val-Cit, Cit-Val, Ala-Ala, Ala-Cit, Cit-Ala, Asn-Cit, Cit-Asn, Cit-Cit, Val-Glu, Glu-Val, Ser-Cit, Cit-Ser, Lys-Cit, Cit-Lys, Asp-Cit, Cit-Asp, Ala-Val, Val-Ala, Phe-Lys, Val-Lys, Ala-Lys, Phe-Cit, Leu-Cit, 111-Cit, Phe-Arg, and Trp-Cit. In certain embodiments, the dipeptide is selected from Cit-Val and Ala-Val.

[0214] In any of the various embodiments of ADCs described above or herein, the ADC may have a drug:antibody ratio (or, in this case, drug:ABM ratio) ranging from 1 to 20, more typically from 2 to 10.

[0215] 6.5. Nucleic Acids and Host Cells In another aspect, the present disclosure provides a nucleic acid encoding the ABM of the present disclosure. In some embodiments, the ABM is encoded by a single nucleic acid. In other embodiments, the ABM is encoded by multiple (e.g., two, three, four, or more) nucleic acids.

[0216] A single nucleic acid can encode an ABM comprising a single polypeptide chain, an ABM comprising two or more polypeptide chains, or a portion of an ABM comprising three or more polypeptide chains (e.g., a single nucleic acid can encode two polypeptide chains of an ABM comprising three, four or more polypeptide chains, or three polypeptide chains of an ABM comprising four or more polypeptide chains). For separate expression control, open reading frames encoding two or more polypeptide chains can be placed under the control of separate transcriptional regulatory elements (e.g., promoters and / or enhancers). Open reading frames encoding two or more polypeptides can also be controlled by the same transcriptional regulatory element and separated by an internal ribosome entry site (IRES) sequence, allowing translation into separate polypeptides.

[0217] In some embodiments, an ABM comprising two or more polypeptide chains is encoded by two or more nucleic acids. The number of nucleic acids encoding the ABM can be equal to or less than the number of polypeptide chains in the ABM (e.g., when two or more polypeptide chains are encoded by a single nucleic acid).

[0218] The nucleic acids of the present disclosure can be DNA or RNA (eg, mRNA).

[0219] In another aspect, the disclosure provides host cells and vectors containing the nucleic acids of the disclosure. The nucleic acids can be present in a single vector or in separate vectors present in the same host cell or in separate host cells, as described in more detail herein below.

[0220] Vectors The present disclosure provides vectors comprising nucleotide sequences encoding the ABMs or ABM components described herein, e.g., one or two of the polypeptide chains of a half antibody. Vectors include, but are not limited to, viruses, plasmids, cosmids, lambda phage, or yeast artificial chromosomes (YACs).

[0221] Numerous vector systems can be used. For example, one class of vectors utilizes DNA elements derived from animal viruses such as bovine papillomavirus, polyomavirus, adenovirus, vaccinia virus, baculovirus, retrovirus (Rous sarcoma virus, MMTV, or MOMLV), or SV40 virus. Another class of vectors utilizes RNA elements derived from RNA viruses such as Semliki Forest virus, eastern equine encephalitis virus, and flaviviruses.

[0222] In addition, cells that have stably integrated the DNA into their chromosomes can be selected by introducing one or more markers that allow for the selection of transfected host cells. Markers can provide, for example, prototrophy to auxotrophic hosts, resistance to biocides (e.g., antibiotics), or resistance to heavy metals such as copper. The selectable marker gene can be directly linked to the DNA sequence to be expressed or introduced into the same cell by cotransformation. Additional elements may be required for optimal mRNA synthesis. These elements may include splice signals, as well as transcription promoters, enhancers, and termination signals.

[0223] When the expression vector or DNA sequence containing construct is prepared for expression, the expression vector can be transfected or introduced into suitable host cell.To achieve this, various techniques can be used, such as protoplast fusion, calcium phosphate precipitation, electroporation, retroviral transduction, viral transfection, gene gun, lipid-based transfection or other conventional techniques.The method and conditions for culturing the resulting transfected cells and recovering expressed polypeptide are known to those skilled in the art, and can be modified or optimized according to the specific expression vector and mammalian host cell used based on this description.

[0224] 6.5.2.Cells The present disclosure also provides a host cell comprising a nucleic acid of the present disclosure.

[0225] In one embodiment, the host cell is genetically engineered to contain one or more nucleic acids described herein.

[0226] In one embodiment, host cells are genetically engineered by using an expression cassette. The phrase "expression cassette" refers to a nucleotide sequence that can affect the expression of a gene in a host that is compatible with such a sequence. Such a cassette can include a promoter, an open reading frame with or without introns, and a termination signal. Additional factors that are necessary or useful for producing expression, such as an inducible promoter, can also be used.

[0227] The present disclosure also provides host cells comprising the vectors described herein.

[0228] The cell can be, but is not limited to, a eukaryotic cell, a bacterial cell, an insect cell, or a human cell. Suitable eukaryotic cells include, but are not limited to, Vero cells, HeLa cells, COS cells, CHO cells, HEK293 cells, BHK cells, and MDCKII cells. Suitable insect cells include, but are not limited to, Sf9 cells.

[0229] Pharmaceutical Compositions The ABM and / or ADC of the present disclosure may be in the form of a composition comprising the ABM and / or ADC and one or more carriers, excipients, and / or diluents, optionally together with one or more other agents that provide improved translocation, delivery, tolerance, etc. The composition may be formulated for a particular use, such as pharmaceutical use in humans or veterinary use. The form of the composition (e.g., dry powder, liquid formulation, etc.), and the excipients, diluents, and / or carriers used, will depend on the intended use of the ABM and / or ADC, and the mode of administration for therapeutic use.

[0230] The dose of an antigen-binding molecule, such as a monospecific or bispecific antigen-binding molecule, administered to a patient can vary depending on the patient's age and size, the target disease, condition, route of administration, and the like. A preferred dose is typically calculated according to body weight or body surface area. When a bispecific antigen-binding molecule of the present disclosure is used for therapeutic purposes in an adult patient, it may be advantageous to administer the antigen-binding molecule of the present disclosure intravenously, typically at a single dose of about 0.01 to about 20 mg / kg body weight, more preferably at a single dose of about 0.02 to about 7, about 0.03 to about 5, or about 0.05 to about 3 mg / kg body weight. The frequency and duration of treatment can be adjusted depending on the severity of the condition. Effective doses and schedules for administering antigen-binding molecules can be determined empirically; for example, the patient's progress can be monitored by periodic evaluation, and the dose can be adjusted accordingly. Furthermore, interspecies scaling of dosages can be performed using methods well known in the art (e.g., Mordenti et al., 1991, Pharmaceut. Res. 8:1351).

[0231] For therapeutic use, the composition may be provided as part of a sterile pharmaceutical composition containing a pharmaceutically acceptable carrier. The composition may be in any suitable form (depending on the desired method of administration to a patient). The pharmaceutical composition may be administered to a patient by a variety of routes, including oral, transdermal, subcutaneous, intranasal, intravenous, intramuscular, intratumoral, intrathecal, topically, or locally. The most suitable route for administration in any given case will depend on the particular antibody and / or ADC, the subject, and the nature and severity of the disease and the subject's physical condition. Typically, the pharmaceutical composition will be administered intravenously or subcutaneously.

[0232] The pharmaceutical composition can be conveniently presented in a unit dosage form containing a predetermined amount of the ABM and / or ADC disclosed herein per dose. The amount of ABM and / or ADC contained in the unit dose will depend on the disease being treated and other factors well known in the art. Such a unit dosage can be in the form of a lyophilized dry powder containing an amount of ABM and / or ADC suitable for a single administration, or in liquid form. The dry powder unit dosage form can be packaged in a kit with a syringe, a suitable amount of diluent, and / or other components useful for administration. The liquid unit dosage can be conveniently provided in the form of a syringe pre-filled with an amount of ABM and / or ADC suitable for a single administration.

[0233] Pharmaceutical compositions may also be supplied in bulk, as they contain an amount of the ADC suitable for multiple administrations.

[0234] Pharmaceutical compositions can be prepared for storage as lyophilized formulations or aqueous solutions by mixing ABM and / or ADC having the desired purity with any pharmaceutically acceptable carrier, excipient, or stabilizer (all of which are referred to herein as "carriers") typically used in the art, i.e., buffers, stabilizers, preservatives, isotonicity agents, non-ionic detergents, antioxidants, and various other additives. See Remington's Pharmaceutical Sciences, 16th edition (Osol, ed. 1980). Such additives should be nontoxic to recipients at the dosages and concentrations used.

[0235] Buffering agents help maintain a pH in a range that approximates physiological conditions. They can be present in a wide variety of concentrations, but will typically be present at concentrations ranging from about 2 mM to about 50 mM. Buffering agents suitable for use in the present disclosure include both organic and inorganic acids and their salts, such as citrate buffers (e.g., monosodium citrate-disodium citrate mixtures, citric acid-trisodium citrate mixtures, citric acid-monosodium citrate mixtures, etc.), succinate buffers (e.g., succinic acid-monosodium succinate mixtures, succinic acid-sodium hydroxide mixtures, succinic acid-disodium succinate mixtures, etc.), tartrate buffers (e.g., tartaric acid-sodium tartrate mixtures, tartaric acid-potassium tartrate mixtures, tartaric acid-sodium hydroxide mixtures, etc.), fumarate buffers (e.g., fumaric acid-monosodium fumarate mixtures, fumaric acid-monosodium fumarate mixtures, etc.), and the like. Examples of suitable buffers include: disodium fumarate mixtures, monosodium fumarate-disodium fumarate mixtures, etc.), gluconate buffers (e.g., gluconic acid-sodium glyconate mixtures, gluconic acid-sodium hydroxide mixtures, gluconic acid-potassium glyconate mixtures, etc.), oxalate buffers (e.g., oxalic acid-sodium oxalate mixtures, oxalic acid-sodium hydroxide mixtures, oxalic acid-potassium oxalate mixtures, etc.), lactate buffers (e.g., lactic acid-sodium lactate mixtures, lactic acid-sodium hydroxide mixtures, lactic acid-potassium lactate mixtures, etc.), and acetate buffers (e.g., acetic acid-sodium acetate mixtures, acetic acid-sodium hydroxide mixtures, etc.). In addition, phosphate buffers, histidine buffers, and trimethylamine salts such as Tris can be used.

[0236] Preservatives may be added to retard microbial growth in amounts ranging from about 0.2% to 1% (w / v). Preservatives suitable for use in the present disclosure include phenol, benzyl alcohol, metacresol, methylparaben, propylparaben, octadecyldimethylbenzylammonium chloride, benzalkonium halides (e.g., chloride, bromide, and iodide), hexamethonium chloride, and alkylparabens such as methyl or propylparaben, catechol, resorcinol, cyclohexanol, and 3-pentanol. Tonicity adjusting agents, also known as "stabilizers," may be added to ensure the isotonicity of the liquid compositions of the present disclosure and include polyhydric sugar alcohols, such as trihydric or higher sugar alcohols, such as glycerin, erythritol, arabitol, xylitol, sorbitol, and mannitol. Stabilizers refer to a broad category of excipients whose functions can range from bulking agents to additives that help solubilize the therapeutic agent or prevent denaturation or adhesion to the container wall. Typical stabilizers include polyhydric sugar alcohols (listed above); amino acids such as arginine, lysine, glycine, glutamine, asparagine, histidine, alanine, ornithine, L-leucine, 2-phenylalanine, glutamic acid, threonine, and the like; organic sugars or sugar alcohols such as lactose, trehalose, stachyose, mannitol, sorbitol, xylitol, ribitol, myo-inisitol, galactitol, glycerol, and the like (including cyclitols such as inositol); polyethylene glycol; amino acid polymers; sulfur-containing reducing agents such as urea, glutamine, and the like. The sugars may be thiones, thioctic acid, sodium thioglycolate, thioglycerol, α-monothioglycerol, and sodium thiosulfate; low molecular weight polypeptides (e.g., peptides of 10 residues or less); proteins, such as human serum albumin, bovine serum albumin, gelatin, or immunoglobulins; hydrophilic polymers, such as polyvinylpyrrolidone; monosaccharides, such as xylose, mannose, fructose, glucose; disaccharides, such as lactose, maltose, sucrose, and trehalose; and trisaccharides, such as raffinose; and polysaccharides, such as dextran.The stabilizer may be present in an amount ranging from 0.5 to 10% by weight per weight of the ADC.

[0237] Nonionic surfactants or detergents (also known as "wetting agents") can be added to help solubilize glycoproteins and protect them against agitation-induced aggregation, which also allows the formulation to be exposed to stressed shear surfaces without causing denaturation of the protein. Suitable nonionic surfactants include polysorbates (e.g., 20, 80), poloxamers (e.g., 184, 188), and pluronic polyols. The nonionic surfactant can be present in a range of about 0.05 mg / mL to about 1.0 mg / mL, e.g., about 0.07 mg / mL to about 0.2 mg / mL.

[0238] Additional miscellaneous excipients include bulking agents (eg, starch), chelating agents (eg, EDTA), antioxidants (eg, ascorbic acid, methionine, vitamin E), and cosolvents.

[0239] 6.7. Therapeutic Indications The ABMs, ADCs, and pharmaceutical compositions of the present disclosure can be used to treat conditions associated with the antigen or target molecule bound by the ABM of the present disclosure, e.g., conditions associated with abnormal expression or activity of the antigen or target molecule, or abnormal cells or tissues expressing the antigen or target molecule. The ABMs, ADCs, and pharmaceutical compositions of the present disclosure can be administered to a subject in need thereof, e.g., a human or non-human animal exhibiting one or more symptoms or signs of a condition associated with abnormal expression or activity of the antigen or target molecule to which the ABM binds.

[0240] In some embodiments, the ABM, ADC, or pharmaceutical composition of the present disclosure is administered to treat any disease or disorder in which stimulation, activation, and / or targeting of an antigen or target molecule is desired. In certain embodiments, the ABM of the present invention may be used to treat, prevent, and / or ameliorate any disease or disorder associated with or mediated by the expression or activity of an antigen or target molecule.

[0241] ABMs of the present disclosure can be exemplified by ABMs containing one or more Fab domains (e.g., Fab1 and / or Fab2) that bind to thymic stromal lymphopoietin ("TSLP"), e.g., human TSLP. TSLP binds to dendritic cell-mediated CD4 T cells in a pro-allogenic phenotype. + TSLP is an immunocytokine that induces T cell responses (Gilliet et al., 2003, J. Exp. Medicine 197(8):1059-1063). TSLP is involved in the initiation of allergic inflammation (Watanabe et al., 2004, Nature Immunology 5:426-434). TSLP acts on a wide range of cell types (e.g., dendritic cells, CD4 + It acts on T cells, eosinophils, basophils, mast cells, and type 2 innate lymphoid cells (ILC2s) (Mjosberg et al., 2012, Immunity 37(4):649-59) to drive inflammation, and in particular type 2 inflammation (characterized by the production of cytokines IL-5, IL-13, and IL-4). Type 2 inflammation is a hallmark of asthma and other allergic diseases, such as atopic dermatitis and Netherton syndrome. TSLP has been shown to induce fibroblast accumulation and collagen deposition in animals, indicating an additional role in promoting fibrotic disorders.

[0242] Therefore, TSLP antagonist ABMs are useful for treating inflammatory, and particularly allergic inflammatory, and fibrotic disorders. ABMs that bind to TSLP (either monospecifically or bispecifically) can be used to treat conditions associated with TSLP signaling in subjects in need of treatment, for example, human subjects. Exemplary conditions associated with TSLP signaling include asthma, idiopathic pulmonary fibrosis, atopic dermatitis, allergic conjunctivitis, allergic rhinitis, Netherton syndrome, eosinophilic esophagitis (EoE), food allergy, allergic diarrhea, eosinophilic gastroenteritis, allergic bronchopulmonary aspergillosis (ABPA), allergic fungal sinusitis, cancer, rheumatoid arthritis, COPD, systemic sclerosis, keloids, ulcerative colitis, chronic rhinosinusitis (CRS), nasal polyposis, chronic eosinophilic pneumonia, eosinophilic bronchitis, celiac disease, Churg-Strauss syndrome, eosinophilic myalgia syndrome, hypereosinophilic syndrome, eosinophilic granulomatosis with polyangiitis, and inflammatory bowel disease.

[0243] 7. Working Example 7.1. Example 1: Construction of alternative format antigen-binding molecules Non-competitive parent mAbs were selected for the construction of alternative-format bispecific ABMs of human TSLP, a protein belonging to the cytokine family with a molecular weight of approximately 15–18 kDa (depending on glycosylation status). These parent mAbs share a common light chain. All heterodimeric bispecific ABMs were constructed with "knob-into-hole" mutations in the Fc region to promote Fc heterodimer formation (Merchant et al., 1998, Nat Biotechnol. 16:677–681). For the Fc-Fab format (Figures 1B and 2B), the (G4S) n The heavy chain was constructed by connecting the VH-CH1 fragment to the C-terminus of the Fc using a linker (G4S, disclosed as SEQ ID NO: 3), n = 1 to 6. In the clamp format (Figure 3B), the internal Fab fragment is inactive and does not bind to TSLP. This inactive Fab fragment is then linked to the flexible long (G4S) Fab fragment in the reach format (Figure 3A).n The linker (G4S is disclosed as SEQ ID NO: 3), n = 6 to 8, is replaced. In the 2 + 2 tandem Fab format, all four Fab fragments are functional and can bind to antigen (Figures 3C-3D). The short linker between the Fab fragments in the clamp and the 2 + 2 tandem Fab format is 2xG4S (SEQ ID NO: 18) or 3xG4S (SEQ ID NO: 4).

[0244] Similarly, non-competing parental mAbs were selected for the construction of bispecific Fc-Fabs of human ligand X. These parental anti-ligand X mAbs share a common light chain.

[0245] For cell surface targets, Fc-Fabs were constructed in a similar manner using Fab fragments that share a common light chain with the bispecific Fc-Fab, and using the constant regions of either hIgG4 (denoted as hIgG4s) (US9359437B2) or hIgG1 with reduced effector function.

[0246] All antibodies that use human IgG4 constant regions contain the S228P(EU) substitution in the hinge region to minimize half-antibody formation (Labrijn et al., 2009, Nat Biotechnol 27:767-771).

[0247] 7.2. Example 2: Expression of antigen-binding molecules All alternative-format bispecific ABMs were expressed by transient transfection in Expi293F cells (Thermo Fisher Scientific). ABMs in Expi293F supernatants were purified using a ProteinMaker system (Protein BioSolutions, Gaithersburg, MD) equipped with a HiTrap rProteinA FF column (GE Healthcare). After single-step elution, ABMs were neutralized and dialyzed into a final buffer of phosphate-buffered saline (PBS) containing 5% glycerol, aliquoted, and stored at -80°C.

[0248] 7.3. Example 3: Activity of anti-hTSLP bispecific ABMs in bioassays Purified anti-hTSLP bispecific ABMs were evaluated for their ability to inhibit hTSLP activity in a luciferase reporter assay. Baf3 cells stably expressing hIL-7R, hTSLPR, and a STAT3-luciferase reporter were seeded at 40,000 cells / well in IL-3-free medium and incubated overnight. For hTSLP dose-response curves, 1:3 serial dilutions of hTSLP were added to each well, with final concentrations of hTSLP starting at 10 nM (Figure 4A). To determine the blocking activity of anti-hTSLP ABMs, a "race format" blocking assay was used in which ABMs and hTSLP were added simultaneously to reporter cells. Anti-hTSLP ABMs were serially diluted 1:3, with final concentrations of each antibody starting at 100 nM. Human TSLP was added to a concentration approximately at the EC50 of the TSLP dose-response curve. After 5.5 h of incubation, the plates were equilibrated at room temperature for 15 min. 100 μl of One-Glo substrate (Promega) was added to each well. After a 5-minute incubation at room temperature, luminescence was measured in an Envision™ system. The activity of three non-competitive anti-hTSLP parent antibodies, 30206, 30217, and 30230, in the STAT3-luciferase reporter assay is shown in Figure 4B. Three bispecific pairings using these parent mAbs were tested. The conventional hIgG4 bispecific antibody showed similar blocking activity to the corresponding parent antibody combination (Figure 5). For each bispecific pairing, all alternative-format bispecific ABMs showed better blocking activity than the conventional hIgG4 bispecific antibody (Figures 6A-6C). Overall, the best formats were the Fc-Fab (with the hinge configuration shown in Figure 13A) and the 2 + 2 tandem Fab heterodimer of all bispecific pairings tested. The IC of these ABMs was 0.01. 50 The values are summarized in Table 5-1. [Table 4]

[0249] 7.4. Example 4: Size Analysis of In Vitro Complexes Formed Between Anti-hTSLP Bispecific Antibody and Recombinant hTSLP by Asymmetric Flow Field Fractionation (A4F-MALLS) Combined with Multi-Angle Laser Light Scattering Overview Size analysis of the in vivo complexes formed between the anti-TSLP ABMs identified in Table 5-2 below and recombinant hTSLP (REGN4009) was performed using asymmetric flow field fractionation combined with multi-angle laser light scattering (A4F-MALLS): anti-TSLP parent Ab 30206 hIgG4, anti-TSLP parent Ab 30217 hIgG4, anti-TSLP parent Ab 30230 hIgG4, Fc-Fab_30206x30217-2xG4S ("2xG4S" is disclosed as SEQ ID NO: 18), Fc-Fab_30217x30230-2xG4S ("2xG4S" is disclosed as SEQ ID NO: 18), Clamp_30206x30217, Clamp_30217x30230, 2+2 tandem Fab_het_30206x30217, and 2+2 tandem Fab_het_30217x30230. In this study, the Fc-Fab ABM had the hinge format shown in Figure 13A.

[0250] 7.4.2 Materials and Methods 7.4.2.1. Molecules Table 5-2 below lists the molecules analyzed by A4F-MALLS and their alternative designations. [Table 5]

[0251] 7.4.2.2.A4F-MALLS mobile phase buffer Mobile phase buffer (10 mM sodium phosphate, 500 mM sodium chloride, pH 7.0±0.1) was prepared by combining 1.4 g of sodium phosphate monobasic monohydrate, 10.7 g of sodium phosphate dibasic heptahydrate, and 500 mL of 5 M sodium chloride, then bringing the solution to a volume of 5.0 L with HPLC-grade water. The final measured pH of the buffer was 7.0. The mobile phase buffer was filtered (0.2 μm) before use.

[0252] 7.4.2.3.AF-MALLS The A4F-MALLS system consisted of an Eclipse™ 3+A4F separations system coupled to an Agilent 1200 series HPLC system equipped with an ultraviolet (UV) diode array detector, a Wyatt Technology Dawn HELEOS® II laser light scattering (LS) instrument, and an Optilab® T-rEX differential refractometer (RI) detector. The detectors were connected in series in the following order: UV-LS-RI. The LS and RI detectors were calibrated according to the instructions provided by Wyatt Technology.

[0253] Defined amounts of anti-TSLP mAbs were each combined with REGN4009 (recombinant TSLP) and diluted with 1X DPBS, pH 7.4, to obtain an equimolar ratio of 1 μM anti-TSLP mAb to 1 μM hTSLP. Equimolar combinations of each parent mAb were prepared as combination stock solutions, and each combination stock solution was then mixed with an equimolar amount of hTSLP to yield a final solution concentration of 0.5 μM mAb1 + 0.5 μM mAb2 + 1 μM hTSLP. All samples were incubated at ambient temperature for 2 h and maintained unfiltered at 4°C before injection into an Eclipse™ short channel equipped with a W350 spacer foil (spacer thickness 350 μm, spacer width 2.2 cm) using a 10 kDa MWCO regenerated cellulose membrane. Prior to injection of each sample, the channel was pre-equilibrated with mobile phase buffer (10 mM sodium phosphate, 500 mM sodium chloride, pH 7.0 ± 0.1). Bovine serum albumin (BSA, 2 mg / mL, 10 μg sample load) was injected separately and included as a system suitability control.

[0254] The fractionation method consisted of four steps: injection, focusing, elution, and a channel "washout" step. A4F-MALLS mobile phase buffer (10 mM sodium phosphate, 500 mM sodium chloride, pH 7.0 ± 0.1) was used throughout the fractionation method. Each sample (7 μg) was injected for 1 min at a flow rate of 0.2 mL / min, followed by focusing for 3 min at a focusing flow rate of 1.0 mL / min. The sample was eluted for 15 min at a channel flow rate of 1.0 mL / min with a constant crossflow of 3.0 mL / min, followed by a linear gradient crossflow from 3.0 mL / min to 0 mL / min over 5 min. Finally, the crossflow was held at 0 mL / min for an additional 5 min to wash out the channel. BSA was fractionated using the same parameter settings.

[0255] 7.4.2.4.MALLS Data Analysis Data were analyzed using ASTRA V software (version 5.3.4.14, Wyatt Technology). Data were fitted to an equation relating excess scattered light to solute concentration and weight-average molar mass, Mw (Kendrick et al., 2001, Anal Biochem. 299(2):136-46; Wyatt, 1993, Anal. Chim. Acta 272(1):1-40):

number

number

[0256] The molar mass of the BSA monomer served to assess the calibration constants of the light scattering and refractive index detectors during data collection (system suitability check). The relative standard deviation (RSD%) of the mean molar mass of BSA determined from the UV and RI detectors was ≤5.0%.

[0257] The light scattering detector normalization factor, interdetector delay, and band broadening term were calculated from the BSA chromatogram collected for the A4F-MALLS conditions used, and these values were applied to the data files collected for all other samples to correct for these aspects.

[0258] The dn / dc values and extinction coefficients (corrected for glycosylation) at 215 nm or 280 nm were experimentally determined using the protein conjugate analysis provided in the Astra software. All protein-protein complex samples were analyzed using the corrected extinction coefficients and dn / dc values.

[0259] 7.4.3.Results A4F-MALLS was used to assess the relative size distribution of complexes formed between several anti-hTSLP ABMs and hTSLP. The theoretical molar masses and predicted stoichiometries of potential ABM complexes with hTSLP are shown in Tables 5-3 and 5-4. [Table 6] [Table 7]

[0260] As expected, each individual parental anti-TSLP mAb (H4H30206P2, H4H30217P2, H4H30230P2) formed standard 1:1 and 1:2 complexes with hTSLP when combined in equimolar ratios (peak 3, approximately 179 kDa, Figure 7, Table 5-5). [Table 8]

[0261] However, when different combinations of the two parental mAbs (H4H30206P2 + H4H30217P2 and H4H30217P2 + H4H30230P2) were mixed with equimolar amounts of hTSLP, a heteromeric distribution of heteromeric complexes was observed, indicating that each parental mAb could bind to the same molecule of hTSLP to form an extended antibody-antigen lattice in a process termed "paper doring" (Figure 8). In these samples, a distinct peak (peak 4) with a molar mass of approximately 342 kDa was observed, followed by a broad series of lower-resolution species (peak 5) with a wide molar mass distribution ranging from approximately 650 to 5,000 kDa. Based on the calculated molar masses of the individual components, peak 4 likely represents a 2:2 mAb:hTSLP complex, while peak 5 corresponds to a heteromeric distribution of higher-order heteromeric complexes consisting of ≥4 molecules of mAb coordinating ≥3 molecules of hTSLP (Tables 5-6). [Table 9]

[0262] In addition, we also investigated the complexes formed between hTSLP and a set of novel bispecific antibodies (TS-FC1-eL1, TS-FC6-eL2) derived from the same parental mAb combination tested above, each possessing two unique Fab domains attached to the C-terminus of a human Fc domain (Fc-Fab). Unlike the results obtained with the parental mAb combination, each Fc-Fab bispecific antibody (bsAb) primarily formed a distinct 1:1 complex with hTLSP (peak 3, approximately 178 kDa; Figure 9, Tables 5-7), with little to no additional higher-order complexes ("paper doring") observed. [Table 10]

[0263] This indicates that both Fab domains on each of the Fc-Fab bsAbs prefer to engage with the same molecule of hTSLP forming a monoecious bivalent interaction, thus eliminating the process of "paper doring."

[0264] Two additional sets of the disclosed ABM formats, bearing either an additional external Fab domain on each binding arm (2+2 tandem Fabs, TS-CL2-eL2 and TS-CL3-eL2) or an additional internal nonbinding Fab on each arm (clamps, TS-CL4-eL1 and TS-CL6-eL1), were also evaluated for complex formation with hTSLP in a similar manner. In general, each clamp ABM appeared to form some degree of 1:1 complex with hTSLP (peak 3, approximately 272 kDa; Figure 10, Tables 5-8). However, a broad, heterogeneous distribution of higher-order complexes (peak 5, approximately 650-7000 kDa; Figure 10, Tables 5-8) exhibiting variable levels of "paper doring" could also be detected in these samples. [Table 11]

[0265] Finally, when mixed with equimolar amounts of hTLSP, each 2+2 tandem Fab bsAb exhibited the highest tendency for "paper doping" of all novel bispecific formats tested. In these samples, we observed a distinct peak (Peak 2, approximately 255 kDa) consistent with the free 2+2 tandem Fab bsAb, followed by a series of broad, lower-resolution peaks (Peaks 4-5, approximately 500-14,000 kDa; Figure 11, Tables 5-9) representing a heterogeneous distribution of increasingly larger species terminating in very large complexes with molar masses exceeding 10 megadaltons. [Table 12]

[0266] 7.5. Example 5: Linker Optimization in Anti-hTSLP Fc-Fab A series of anti-hTSLP 30217x30230 bispecific Fc-Fabs were constructed using different linkers, ranging from a 2-amino acid GS linker to a 30-amino acid 6xG4S linker (SEQ ID NO: 38). The activity of these Fc-Fabs was evaluated in an hTSLP STAT3-luciferase reporter assay (Figure 12). The best blocking activity was observed for Fc-Fabs with linker lengths of 2 to 5xG4S (G4S is disclosed as SEQ ID NO: 3). Different hinge formats were also evaluated using the 30217x30230 bispecific Fc-Fab as an example (Figure 13). In format #1, the hinge sequence is at the N-terminus of the Fc-Fab, as occurs in the native hIgG4 sequence, and has a S228P(EU) substitution (Figure 13A). In format #2, the same hinge sequence is removed from the N-terminus of the Fc-Fab and replaced with a (G4S) C-terminus of the Fc CH3 domain. n In format #3, the hinge is also inserted between the CH3 domain and the (G4S) linker (G4S is disclosed as SEQ ID NO: 3) (Figure 13B). n The G4S sequence is located between the linker and the hTSLP 30217x30230 (G4S is disclosed as SEQ ID NO: 3). However, the upper hinge sequence is replaced with a G4S sequence (G4S is disclosed as SEQ ID NO: 3) (Figure 13C). All three hinge formats were combined with a 1xG4S (SEQ ID NO: 3) or 4xG4S linker (SEQ ID NO: 19) to construct anti-hTSLP 30217x30230 bispecific Fc-Fabs. The activity of these Fc-Fabs was evaluated in an hTSLP STAT3-luciferase reporter assay (Figure 13D). For the Fc-Fab with the 4xG4S linker (SEQ ID NO: 19), different hinge formats had little effect on their TSLP-blocking activity, with hinge format #1 showing the best activity. For the Fc-Fab with the 1xG4S linker (SEQ ID NO: 3), hinge format #1 had a 5- to 10-fold better IC50 than the other two hinge formats.

[0267] 7.6. Example 6: Biacore Analysis of Fc-Fab Binding to Fc Receptors The equilibrium dissociation constants (K ) of different anti-TSLP Fc-Fab antibodies binding to purified recombinant human FcγR and human-derived FcRn receptor subtypes D The Fc-Fab constructs assayed were TSLP 30206x30217 Fc_Fab 2xG4S ("2xG4S" is disclosed as SEQ ID NO: 18) (also referred to as REGN8759) and TSLP 30230x30217 Fc_Fab 2xG4S ("2xG4S" is disclosed as SEQ ID NO: 18) (also referred to as REGN7860), along with anti-FelD1(-)-IgG1 and IgG4 isotype controls (referred to as REGN1932 and REGN1945, respectively). The Fc receptors assayed were human FcγRIIA(H131)-myc.6xHis, human FcγRIIA(R167)-10xHis, human FcγRIIB-myc.6xHis, human FcγRIIIA(F176)-myc.6xHis, human FcγRIIIB-mmh, human FcRn-mmh, and human FcγRI-6xHis.

[0268] 7.6.1 Materials and Methods All binding studies were performed in 10 mM HEPES, 150 mM NaCl, 3 mM EDTA, and 0.05% v / v Tween-20 surfactant, pH 7.4 (HBS-ET) or PBS, 0.05% v / v Tween-20 surfactant, pH 6.0 (PBS-T-pH 6.0) running buffer at 25° C. The MASS-2 / Biacore 3000 CM5 sensor surface was derivatized by amine coupling with either a mouse anti-penta-histidine monoclonal antibody ("penta-histidine" is disclosed as SEQ ID NO: 34) (GE Healthcare) or an anti-myc monoclonal antibody (REGN642) to capture FcγR and FcRn receptor extracellular domains expressed at the C-terminal myc-myc-hexahistidine ("hexahistidine" is disclosed as SEQ ID NO: 35) or histidine regions. Binding studies were performed with different anti-TSLP Fc-Fabs and a wild-type Fc isotype control. Different concentrations of anti-TSLP Fc-Fab (ranging from 5 μM to 0.3125 μM, 2-fold dilutions) prepared in HBS-ET or PBS-T pH 7.4 and pH 6.0 running buffers were injected over the FcγR and FcRn receptor capture surfaces at a flow rate of 50 μL / min. The association of all anti-TSLP Fc-Fabs to the captured FcγR and FcRn receptors, respectively, was monitored for 1.5–2 min, and their dissociation in HBST running buffer was monitored for 10 min. At the end of each cycle, the FcγR and FcRn receptor capture surfaces were regenerated using a 20–30 s injection of 10 mM glycine-HCl pH 1.5 for mouse anti-penta-histidine monoclonal antibody ("penta-histidine" is disclosed as SEQ ID NO: 34) or anti-myc monoclonal antibody. All binding kinetic experiments were carried out at 25°C.

[0269] Data Analysis The binding-dissociation equilibrium constant (KD) and dissociation half-life (t1 / 2) were calculated from the kinetic rates as follows: KD (M) = kd / ka and t1 / 2 (min) = ln2 / (60 x kd).

[0270] 7.6.3.Results The binding kinetics parameters for different anti-TSLP Fc-Fabs and control antibodies binding to different FcγR and FcRn receptors of the present disclosure at 25°C are shown in Tables 5-10 and 5-11, respectively. In Table 5-10, NT means not tested, and IC means indeterminate. In Table 5-11, NB means no binding, and IC means indeterminate. [Table 13] [Table 14]

[0271] 7.7. Example 7: Pharmacokinetic Evaluation of Anti-TSLP Fc-Fab Bispecific Antibodies in Wild-Type Mice Overview Evaluation of the pharmacokinetic profiles of two anti-TSLP Fc-Fab bispecific binding molecules, (1) a 30206 x 30217 IgG4 Fc-Fab bispecific with a 2xG4S linker (SEQ ID NO: 18), also known as REGN8759, and (2) a 30230 x 30217 IgG4 Fc-Fab bispecific with a 2xG4S linker (SEQ ID NO: 18), also known as REGN 8760, compared to an anti-fel d 1 IgG4 isotype control, REGN1945, an irrelevant conventional bispecific IgG4 control, H4H21237D, and an hFcγ homodimer, REGN1627, was performed in C57BL / 6 wild-type (WT) mice.

[0272] 7.7.2. Materials and Methods Cohorts contained five mice per antibody tested. Mice administered REGN8759, REGN8760, REGN1945, and H4H21237D received a single subcutaneous (SC) 1 mg / kg dose. Mice administered the hFcγ homodimer, REGN1627, received a SC dose normalized based on the molar equivalent (0.35 mg / kg) to other antibodies in the study. Blood samples were collected 6 hours after administration and at days 1, 2, 3, 4, 7, 10, 14, and 21. Blood was processed to serum and frozen at -80°C until analysis. Total and functional serum concentrations of REGN8759 and REGN8760, as well as total serum concentrations of REGN1945, H4H21237D, and REGN1627, were measured using the GyroLab xPlore platform (Gyros).

[0273] Gyros technology uses an affinity flow-through format for automated immunoassays with laser-induced fluorescence detection. Samples are loaded onto a compact disc (CD) containing multiple radially arranged nanoliter-scale affinity capture columns. Liquid flow is controlled by centrifugal and capillary forces.

[0274] For measurements of total and functional REGN8759, REGN8760, and total REGN1945, H4H21237D, and REGN1627 in serum, 100 μg / mL of test article- or control article-specific biotinylated capture reagent (Tables 5-11) was added to a Gyrolab Bioaffy 200CD containing an affinity column preloaded with streptavidin-coated beads (Dynospheres). Standards used for calibration (Tables 5-11) were analyzed at concentrations ranging from 0.488 to 2000 ng / mL. Serial dilutions of serum samples were prepared in phosphate-buffered saline (PBS) containing 0.5% bovine serum albumin (BSA). Serial dilutions of standards were prepared in PBS + 0.5% BSA containing 2% normal mouse serum (NMS). Duplicates of serum sample singlets and standards diluted 1:50 were applied to the capture reagent-coated affinity column at room temperature. Captured human IgG was detected using an Alexa-647-conjugated mouse anti-human IgG1 / hIgG4 monoclonal antibody (REGN2567, 0.5 μg / mL) diluted in Rexxip F buffer (Gyros). The resulting fluorescent signal was recorded in response units (RU) by a GyroLab xPlore instrument. The lower limit of quantitation (LLOQ) for each assay was defined as the lowest concentration on the standard curve at which quality control (QC) samples consistently deviated by less than 25% from the expected concentration (Tables 5-12). Sample concentrations were determined by interpolation from the standard curve constructed using a four-parameter logistic curve fit in Gyrolab Evaluator Software. The mean concentrations from two replicate experiments were used to calculate the final concentration. [Table 15]

[0275] PK parameters were determined by non-compartmental analysis (NCA) using Phoenix® WinNonlin® software version 6.3 (Certara, LP, Princeton, NJ) and an extravascular administration model. The respective mean concentration values (total drug) for each antibody were used to calculate the maximum observed serum concentration (C). max ), the estimated observed half-life (t 1 / 2 ), area under the concentration curve versus time to last measurable concentration (AUC last ), and all PK parameters, including antibody clearance rate (Cl), were determined using the linear trapezoidal rule with linear interpolation and uniform weighting.

[0276] 7.7.3.Results Following 1 mg / kg SC administration of the anti-TSLP Fc-Fab bispecific antibody and control in WT mice, REGN8759 and REGN8760 produced similar maximum total concentrations of drug in serum (C max = 11.7 and 10.7 μg / mL), as well as hIgG4 isotype control, REGN1945, irrelevant conventional bispecific IgG4 control, H4H21237D, and hFcγ homodimer, REGN1627 (C max dose-normalized) at approximately 1.5- to 2-fold lower concentrations (C max = 8.2, 7.8, and 6.4 μg / mL).

[0277] In addition, REGN8759, REGN8760, REGN1945, and H4H21237D all had similar half-life values (T 1 / 2 = 12.1, 12.2, 10.9, and 11.2 days), with REGN1627 having a faster half-life (6.4 days) compared to all other tested drugs. Additionally, REGN8759 and REGN8760 showed AUClast = 88.0, 84.1, and 19.7, respectively, when compared to REGN1945, H4H21237D, and REGN1627. last / D = 56.2(d*μg / mL) / (mg / kg), respectively, compared with Cl = 9.5, 8.2, and 45.2 mL / day / kg, respectively, resulting in better drug exposure (AUC last = 131, and 122 (d*μg / mL) / (mg / kg)) and showed slower clearance rates (Cl = 5.2, 5.5 mL / day / kg, respectively).

[0278] Furthermore, total and functional TSLP-binding concentrations of REGN8759 and REGN8760 were comparable at all time points tested, indicating that these Fc-Fab molecules remained intact at 21 days. Overall, the PK profiles are similar or better for REGN8759 and REGN8760 compared with the hIgG4 isotype control, an irrelevant conventional bispecific IgG4 control, or the hFcγ homodimer.

[0279] A summary of data for total and functional REGN8759 and REGN8760 drug concentrations, and total REGN1945, H4H21237D, and REGN1627 drug concentrations is summarized in Table 5-13, mean PK parameters are shown in Table 5-14, and mean total antibody concentrations versus time are shown in Figures 14 and 15. [Table 16-1] [Table 16-2] [Table 17]

[0280] PK parameters were derived from the mean concentration versus time profiles of total drug concentrations. 1 / 2 and AUC last is based on concentrations through day 21. Mean ± SEM values for each PK parameter are shown for all dose groups.

[0281] Abbreviation:AUClast = area under the curve from time of administration to last measurable concentration, AUC last / D = AUC final dose normalized to 1 mg / kg administration, t = terminal elimination half-life, C max = peak concentration, C max / d = Cmax dose normalized to 1 mg / kg administration, t max =C max is observed, Cl = rate of antibody clearance over time, SEM = standard error of the mean.

[0282] 7.8. Example 8: Biacore Analysis of Anti-Ligand X Fc-Fab Binding to Ligand X Fab fragments from three non-competitive mAbs against human ligand X, mAbX1, mAbX2, and mAbX3, were used to generate bispecific Fc-Fabs of human ligand X, soluble monomeric proteins with molecular weights ranging from 15 to 20 kDa, in which the linker was G4S2 (i.e., GGGGSGGGGS (SEQ ID NO: 18)). The Fc-Fabs had the hinge format shown in Figure 13A.

[0283] The equilibrium dissociation constant (KD) of ligand X binding to purified anti-ligand X antibody was determined using a real-time surface plasmon resonance biosensor on a Biacore T200 instrument. The Biacore sensor surface was derivatized by amine coupling with a monoclonal mouse anti-human Fc antibody (REGN2567) to capture anti-ligand X antibody expressed with the human Fc constant region. Biacore binding studies were performed in HBST running buffer (0.01 M HEPES pH 7.4, 0.15 M NaCl, 3 mM EDTA, 0.05% v / v surfactant P20). Human ligand X was obtained from an in-house source (REGN138). Different concentrations of human ligand X (ranging from 90 nM to 0.12 nM, 3-fold dilutions) prepared in HBST running buffer were injected over the anti-ligand X antibody capture surface at a flow rate of 50 μL / min. The association of all Ligand X reagents to each of the captured monoclonal antibodies was monitored for 4 minutes, and their dissociation in HBST running buffer was monitored for 10 minutes. All binding kinetic experiments were performed at 37°C. Kinetic association (ka) and dissociation (kd) rate constants were determined by fitting the real-time sensorgrams to a 1:1 binding model using Biaevaluation curve-fitting software. The binding dissociation equilibrium constant (KD) and dissociation half-life (t1 / 2) were calculated from the kinetic rate constants as follows: KD(M)=kd / ka and t1 / 2(min)=ln2 / (60xkd).

[0284] The binding kinetic parameters for human ligand X binding to anti-ligand X antibodies at 37°C are shown in Table 5-15. At 37°C, the anti-ligand X Fc-Fab of the present disclosure bound to human ligand X with K values ranging from 0.25 pM to 18.4 pM, and the parental mAb bound to human ligand X with K values of 0.56 pM and 557 pM, respectively, as shown in Table 5-15. [Table 18]

[0285] 7.9. Example 9: Activity of Anti-Human Ligand X Bispecific Fc-Fab in Bioassays Purified anti-human ligand X bispecific Fc-Fabs were evaluated for their ability to inhibit human ligand X in a receptor X signaling bioassay. Bioassays for ligand X signaling through receptor X were performed using an engineered luciferase reporter cell line. Reporter cells were seeded at 10,000 cells / well in Opti-MEM (Gibco) containing 0.1% fetal bovine serum (Seradigm) and incubated overnight. For ligand X dose-response curves, 1:3 serial dilutions of ligand X were added to each well, with final concentrations of ligand X starting at 2 nM. To determine the blocking activity of anti-ligand X parental mAbs and bispecific Fc-Fabs, a "race format" blocking assay was used, in which the antibody and ligand X were added simultaneously to reporter cells. The anti-ligand X antibody was serially diluted 1:3, with a final concentration starting at 100 nM. Human ligand X was added to a fixed concentration of 10 pM, 100 pM, or 1 nM. After 5.5 hours of incubation, the assay plate was equilibrated at room temperature for 15 minutes. 100 μl of One-Glo substrate (Promega) was added to each well. After a 5-minute incubation at room temperature, luminescence was measured on the Envision.

[0286] The activities of three anti-human ligand X bispecific Fc-Fabs in receptor X bioassays are shown in Figures 16A-16C (mAbX1 x mAbX2), Figures 17A-17C (mAbX2 x mAbX3), and Figures 18A-18C (mAbX1 x mAbX3). Their activities were compared with the corresponding anti-human ligand X parent mAbs in the same assay. mAbX1 x mAbX2 Fc-Fab had the best blocking activity, with a significantly improved IC over the parent anti-ligand X mAb. 50Figures 17A-17C and 18A-18C show the IC values of the bispecific Fc-Fabs. One of the parent mAbs, mAbX3, does not block ligand X activity relative to baseline in the bioassay, even when the mAb is in 100- to 1000-fold molar excess over human ligand X. Interestingly, two Fc-Fabs using mAbX3 Fab are able to block ligand X activity relative to baseline (Figures 17A-17C and Figures 18A-18C). These results demonstrate the superior activity of the bispecific Fc-Fabs when compared to their parent anti-ligand X mAbs. The IC values of these anti-ligand X antibodies 50 The values are summarized in Table 5-16. [Table 19]

[0287] 7.10. Example 10: Size Analysis of In Vitro Complexes Formed Between Antiligand X Heterodimers and Recombinant Ligand X by Asymmetric Flow Field Fractionation Combined with Multi-Angle Laser Light Scattering (A4F-MALLS) Size analysis of in vitro complexes formed between recombinant ligand X and bispecific mAb X1 x mAb X2 in Fc-Fab, clamp, and 2+2 tandem Fab heterodimer formats, compared to complexes with the parental mAb, was performed using asymmetric flow field fractionation coupled with multi-angle laser light scattering (A4F-MALLS) as described in Section 7.4. The results of this analysis are shown in Figures 19A-19E. Figures 19A and 19B show the results of in vitro analysis of complexes between ligand X and parental mAbs (alone or in combination), Figure 19C shows the results of in vitro analysis of complexes between ligand X and mAb X1 x mAb X2 Fc-Fab, Figure 19D shows the results of in vitro analysis of complexes between ligand X and mAb X1 x mAb X2 clamp, and Figure 19E shows the results of in vitro analysis of complexes between ligand X and mAb X1 x mAb X2 2+2 tandem Fab heterodimer. As shown in Figure 19C, the Fc-Fab format exhibits minimal paper doring or aggregation.

[0288] 7.11. Example 11: Fc-Fab maintains binding to cell surface targets In addition to small soluble antigens, cell surface proteins were tested as targets for Fc-Fabs. An IgG antibody against antigen Y, a cell surface antigen, was reformatted into a monospecific Fc-Fab using either the hIgG1 constant region (Figure 20A) or the hIgG4 constant region (US9359437B2) (denoted as hIgG4, Figures 20B, 20C, and 20D) with reduced effector function (shown in Figure 1B, and the hinge format shown in Figure 13A). Three different linkers, 1xG4S (SEQ ID NO: 3), 2xG4S (SEQ ID NO: 18), and 3xG4S (SEQ ID NO: 4), were tested for each anti-antigen Y Fc-Fab. These Fc-Fabs were evaluated for binding to cell surface antigen Y in a flow cytometry (FACS) binding assay. Antigen Y-expressing cells were harvested and resuspended in cold FACS wash buffer (PBS + 1% FBS). For each binding assay, 50,000–100,000 cells were incubated with primary antibody in FACS wash buffer for 30 min at 4°C. Cells were washed twice with cold FACS wash buffer and then incubated with a 1:200 dilution of APC-F(ab)'2 anti-human IgG Fcγ fragment (Jackson ImmunoResearch Laboratories) for 30 min at 4°C. At the end of the incubation, cells were washed twice with cold FACS wash buffer and analyzed on a FACS Canto (BD Biosciences).

[0289] All Fc-Fabs maintained strong binding to cell surface antigen Y. Two sets of Fc-Fabs had similar binding activity to their parent mAbs (Figures 20A and 20B). The other two sets of Fc-Fabs showed moderately reduced binding to antigen Y when compared to their parent mAbs (Figures 20C and 20D). Varying the linker length between 1xG4S (SEQ ID NO: 3) and 3xG4S (SEQ ID NO: 4) had minimal effect on target binding of anti-antigen Y Fc-Fabs.

[0290] Additional cell surface proteins were tested as targets for the Fc-Fabs, including CD3 and a cell surface tumor-associated antigen, antigen Z. The Fc-Fabs had the hinge format shown in Figure 13A. In FACS binding assays, the anti-CD3 hIgG1 Fc-Fab showed specific binding to CD3+ Jurkat cells (Figure 21A), and the anti-antigen Z hIgG1 Fc-Fab showed specific binding to an antigen Z+ cell line (Figure 21B). Varying the linker length between 1xG4S (SEQ ID NO: 3) and 5xG4S (SEQ ID NO: 39) had a slight effect on target binding of these Fc-Fabs, with the shortest linker resulting in moderately weaker binding activity to both CD3 and antigen Z.

[0291] 7.12. Example 12: Bispecific CD3x Antigen Z Fc-Fab is active in bioassays using T cells as effector cells Bispecific Fc-Fabs against CD3 and antigen Z (a cell surface tumor-associated antigen) were generated using the constant region of hIgG1 as described in Example 1. Three different linkers, 1xG4S (SEQ ID NO: 3), 2xG4S (SEQ ID NO: 18), and 3xG4S (SEQ ID NO: 4), were tested for these bispecific Fc-Fabs with the hinge format shown in Figure 13A. The activity of the bispecific Fc-Fabs was evaluated in a Jurkat NFAT-luciferase reporter assay (Figure 22A) and an in vitro cytotoxicity assay (Figure 22B). For the Jurkat NFAT-luciferase reporter assay, a Jurkat / NFAT-Luc reporter cell line was mixed with an antigen Z+ cell line (50,000 cells each) at a 1:1 ratio in a 96-well plate. The CD3xAntigenZ bispecific Fc-Fab was added to each well to a final volume of 100 μl. The reaction was incubated at 37°C for 5 hours. After incubation, the plate was equilibrated at room temperature for 10 minutes before adding 100 μl of One-Glo substrate (Promega) to each well. Luminescence was measured in a Victor cytotoxicity assay. For the cytotoxicity assay, pre-activated human T cells were prepared using CD3 / CD28 beads and human donor PBMCs activated with IL-2 for 7 days. On the day of the cytotoxicity assay, antigen Z+ cells were harvested and labeled with 8 μM calcein-AM (Invitrogen) for 30 minutes. The labeled target cells were washed twice and mixed with the pre-activated human T cells at a 1:10 ratio, approximately 10,000 target cells per well. Serial dilutions of CD3xAntigenZ bispecific Fc-Fab were added to a final volume of 200 μl. The reaction was incubated at 37°C for 3 hours. After incubation, the plate was centrifuged, and 100 μl of the supernatant was transferred to a translucent black clear-bottom plate for fluorescence reading. The CD3x antigen Z bispecific Fc-Fab was active in both Jurkat reporter assays (Figure 22A) and cytotoxicity assays (Figure 22B). In both assays, Fc-Fabs with longer linkers showed stronger activity.

[0292] 8. Specific Embodiments The present disclosure is illustrated by the following Group A and Group B specific embodiments.

[0293] In the specific embodiments and preferred aspects of the claims below, the antigen-binding domain (e.g., Fab) contains humanized or human VH and VL sequences, and the Fc domain comprises a human CH2 and / or CH3 domain and variants thereof, e.g., variants having at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, at least about 99%, or 100% sequence identity to such human sequences. Furthermore, the Fab domain may be a Fab domain composed of two polypeptide chains, a VH polypeptide chain and a VL polypeptide chain as described herein, or a single-chain Fab ("scFab") in which the VH and VL are present in a single polypeptide chain. Unless otherwise specified, the Fab domain may also include domain swapping, e.g., domain swapping present in a crossmab format.

[0294] 8.1. Group A Specific Embodiments 1. Binds to a first target molecule; (a) (i) an Fc region comprising two Fc domains; (ii) comprising a first Fab domain and a second Fab domain; The Fc region, the first Fab domain, and the second Fab domain are of a non-natural immunoglobulin configuration. the first Fab domain and / or the second Fab domain are capable of binding to a first target molecule; (b) an antigen-binding molecule that binds to a first target molecule with greater affinity and / or avidity than a native immunoglobulin comprising at least two Fab domains. 2. Binding to a first target molecule; (a) In the N- to C-terminal orientation (i) a first Fc domain, and (ii) a first polypeptide comprising a first Fab domain comprising a first heavy chain variable region (VH) associated with a first light chain variable region (VL); (b) In the N- to C-terminal orientation (i) a second Fc domain, and (ii) a second polypeptide comprising a second Fab domain comprising a second VH associated with a second VL; The antigen-binding molecule according to embodiment 1, wherein the first Fc domain and the second Fc domain associate with each other to form an Fc region, and optionally the first polypeptide and the second polypeptide are identical. 3. The antigen binding molecule of embodiment 2, comprising a first linker between the first Fc domain and the first VH. 4. The antigen-binding molecule of embodiment 3, wherein the first linker is 5 amino acids to 60 amino acids in length. 5. The antigen-binding molecule of embodiment 3, wherein the first linker is 10 to 60 amino acid residues in length. 6. The antigen-binding molecule of embodiment 3, wherein the first linker is 5 to 20 amino acid residues in length. 7. The antigen-binding molecule of embodiment 3, wherein the first linker is 5 to 30 amino acid residues in length. 8. The antigen-binding molecule of embodiment 3, wherein the first linker is 10 to 30 amino acid residues in length. 9. The antigen-binding molecule of embodiment 3, wherein the first linker is 10 to 20 amino acid residues in length. 10. The antigen-binding molecule of embodiment 3, wherein the first linker is 20 to 50 amino acids in length. 11. The antigen-binding molecule of embodiment 3, wherein the first linker is 25 to 35 amino acids in length. 12. The first linker is G n S or SG n and optionally n is an integer from 1 to 7. 13. The antigen binding molecule of embodiment 12, wherein the first linker comprises a multimer of G4S (SEQ ID NO: 3). 14. The antigen-binding molecule of embodiment 13, wherein the first linker comprises 2 to 6 repeats of G4S (SEQ ID NO: 3). 15. The antigen-binding molecule of embodiment 14, wherein the first linker comprises (G4S)2 (SEQ ID NO: 18), (G4S)3 (SEQ ID NO: 4), or (G4S)4 (SEQ ID NO: 19). 16. The antigen-binding molecule of any one of embodiments 3 to 15, comprising a second linker between the second Fc domain and the second VH. 17. The antigen-binding molecule of embodiment 16, wherein the first linker and the second linker have the same amino acid sequence. 18. The antigen-binding molecule of embodiment 16 or embodiment 17, wherein the second linker is between 5 amino acids and 60 amino acids in length. 19. The antigen-binding molecule of embodiment 16 or embodiment 17, wherein the second linker is between 10 amino acids and 60 amino acids in length. 20. The antigen-binding molecule of embodiment 16 or embodiment 17, wherein the first linker is between 5 amino acids and 20 amino acid residues in length. 21. The antigen-binding molecule of embodiment 16 or embodiment 17, wherein the first linker is between 5 amino acids and 30 amino acid residues in length. 22. The antigen-binding molecule of embodiment 16 or embodiment 17, wherein the first linker is between 10 and 30 amino acid residues in length. 23. The antigen-binding molecule of embodiment 16 or embodiment 17, wherein the first linker is 10 to 20 amino acid residues in length. 24. The antigen-binding molecule of embodiment 16 or embodiment 17, wherein the second linker is 20 amino acids to 50 amino acids in length. 25. The antigen-binding molecule of embodiment 16 or embodiment 17, wherein the second linker is 25 to 35 amino acids in length. 26. The second linker is G n S or SG n wherein n is an integer from 1 to 7. 27. The antigen binding molecule of embodiment 26, wherein the second linker comprises a multimer of G4S (sequence number 3). 28. The antigen-binding molecule of embodiment 27, wherein the second linker comprises 2 to 6 repeats of G4S (SEQ ID NO: 3). 29. The antigen binding molecule of embodiment 28, wherein the second linker comprises (G4S)2 (SEQ ID NO: 18), (G4S)3 (SEQ ID NO: 4), or (G4S)4 (SEQ ID NO: 19). 30. The antigen-binding molecule of any one of embodiments 2-29, wherein the first polypeptide comprises a first hinge domain N-terminal to the first Fc domain, and the second polypeptide comprises a second hinge domain N-terminal to the second Fc domain. 31. The antigen-binding molecule of embodiment 30, wherein the first hinge domain and the second hinge domain are linked via a disulfide bond. 32. The antigen-binding molecule of embodiment 30, wherein the first hinge domain and the second hinge domain are not linked via a disulfide bond. 33. The antigen-binding molecule of any one of embodiments 2-32, wherein the first polypeptide does not comprise a VH that is N-terminal to the first Fc domain. 34. The antigen-binding molecule of any one of embodiments 2-33, wherein the second polypeptide does not comprise a VH that is N-terminal to the second Fc domain. 35. The antigen-binding molecule of any one of embodiments 2 to 29, having one hinge region. 36. The antigen-binding molecule of embodiment 35, having the hinge format shown in Figure 13A. 37. The antigen-binding molecule of embodiment 35, having the hinge format shown in Figure 13C. 38. The antigen-binding molecule of any one of embodiments 2 to 29, having two hinge regions. 39. The antigen-binding molecule of embodiment 38, having the hinge format shown in Figure 13B. 40. The antigen-binding molecule of any one of embodiments 2-39, wherein the first polypeptide and the second polypeptide are non-identical. 41. The antigen-binding molecule of any one of embodiments 2-40, wherein the first VL and the second VL are universal light chains. 42. The antigen-binding molecule of any one of embodiments 2 to 40, wherein the light chain constant region and the first heavy chain constant region (CH1) of the first Fab domain or the second Fab domain are in a crossmab configuration. 43. The antigen-binding molecule of any one of embodiments 1-42, which is bivalent. 44. (a) In the N- to C-terminal orientation (i) a first Fab domain comprising a first VH associated with a first VL; (ii) a first spacer domain; (iii) a first polypeptide comprising a first Fc domain; and (b) In the N- to C-terminal orientation (i) a second Fab domain comprising a second VH associated with a second VL; (ii) a second spacer domain; (iii) a second polypeptide comprising a second Fc domain; and An antigen-binding molecule, wherein the first Fab domain and / or the second Fab domain can bind to a first target molecule, the first Fc domain and the second Fc domain associate with each other to form an Fc region, and optionally the first polypeptide and the second polypeptide are identical. 45. The antigen-binding molecule of embodiment 44, comprising a hinge domain between the first spacer domain and the first Fc domain, and between the second spacer domain and the second Fc domain. 46. The antigen-binding molecule of embodiment 44 or embodiment 45, wherein the hinge domains are linked via a disulfide bond. 47. The antigen-binding molecule of any one of embodiments 44-46, wherein the first VL and the second VL are universal light chains. 48. The antigen-binding molecule of any one of embodiments 44-46, wherein the light chain constant region and the first heavy chain constant region (CH1) of the first Fab domain or the second Fab domain are in crossmab configuration. 49. The antigen-binding molecule of any one of embodiments 44-48, wherein the first spacer domain and the second spacer domain each comprise an extended linker. 50. The antigen-binding molecule of embodiment 49, wherein each extended linker is at least 30 amino acids in length. 51. The antigen-binding molecule of embodiment 49 or embodiment 50, wherein each extended linker is between 30 acid residues and 70 amino acids in length. 52. The antigen-binding molecule of embodiment 49 or embodiment 50, wherein each extended linker is 30 acid residues to 55 amino acids in length. 53. The antigen-binding molecule of embodiment 49 or embodiment 50, wherein each extended linker is 30 to 40 amino acids in length. 54. Each extension linker is n S or SG n wherein n is an integer from 1 to 7. 55. The antigen-binding molecule of embodiment 54, wherein each extended linker comprises a multimer of G4S (sequence number 3). 56. The antigen binding molecule of embodiment 55, wherein each extended linker comprises 5 to 12 repeats of G4S (sequence number 3). 57. The antigen binding molecule of embodiment 56, wherein each extended linker comprises (G4S)6 (SEQ ID NO: 38), (G4S)7 (SEQ ID NO: 36), or (G4S)8 (SEQ ID NO: 37). 58. The antigen-binding molecule of any one of embodiments 44-57, wherein the first and second spacer domains are identical. 59. The antigen-binding molecule of any one of embodiments 44 to 58, which is bivalent. 60. The antigen binding molecule of embodiment 44, wherein the first spacer domain comprises a third Fab domain comprising a third VH associated with a third VL, and the second spacer domain comprises a fourth Fab domain comprising a fourth VH associated with a fourth VL. 61. The antigen-binding molecule of embodiment 60, wherein the third VL and the fourth VL are universal light chains having an Fc region. 62. The antigen binding molecule of embodiment 60 or embodiment 61, wherein the first polypeptide comprises a first linker between the first VH and the third VH, and the second polypeptide comprises a second linker between the second VH and the fourth VH. 63. The antigen-binding molecule of embodiment 62, wherein the first linker and the second linker are each 10 to 60 amino acids in length. 64. The antigen-binding molecule of embodiment 62 or embodiment 63, wherein the first linker and the second linker are each 20 to 50 amino acids in length. 65. The antigen-binding molecule of embodiment 62 or embodiment 63, wherein the first linker and the second linker are each 25 to 35 amino acids in length. 66. The first linker and the second linker each comprise G n S or SG n wherein n is an integer from 1 to 7. 67. The antigen-binding molecule of embodiment 66, wherein the first linker and the second linker each comprise a multimer of G4S (sequence number 3). 68. The antigen-binding molecule of embodiment 67, wherein the first linker and the second linker each comprise 2 to 6 repeats of G4S (sequence number 3). 69. The antigen binding molecule of embodiment 68, wherein the first linker and the second linker each comprise (G4S)2 (SEQ ID NO: 18), (G4S)3 (SEQ ID NO: 4), or (G4S)4 (SEQ ID NO: 19). 70. The antigen-binding molecule of any one of embodiments 62-69, wherein the first linker and the second linker have the same amino acid sequence. 71. The antigen-binding molecule of any one of embodiments 60-70, wherein the third Fab domain and the fourth Fab domain are non-binding. 72. The antigen-binding molecule of embodiment 71, wherein the third VH and the fourth VH are universal heavy chains. 73. The antigen binding molecule of embodiment 71 or embodiment 72, wherein the first Fab domain and the second Fab domain are each capable of binding to the same or different epitopes on the first target molecule. 74. The antigen-binding molecule of any one of embodiments 60-73, which is bivalent. 75. The antigen-binding molecule of any one of embodiments 60-70, wherein the third Fab domain and the fourth Fab domain are each capable of binding to the same or different epitopes. 76. The antigen binding molecule of embodiment 75, wherein the third Fab domain and the fourth Fab domain are each capable of binding to the same target molecule. 77. The antigen binding molecule of embodiment 76, wherein the third Fab domain and the fourth Fab domain are each capable of binding to a first target molecule. 78. The antigen-binding molecule of any one of embodiments 75-77, wherein the first and second Fab domains bind to the same epitope. 79. The antigen-binding molecule of embodiment 78, wherein the first and second Fab domains have identical sequences. 80. The antigen-binding molecule of any one of embodiments 75-79, wherein the third and fourth Fab domains bind to the same epitope. 81. The antigen-binding molecule of embodiment 80, wherein the third and fourth Fab domains have identical sequences. 82. The antigen-binding molecule of any one of embodiments 75-77, wherein the first and third Fab domains bind to the same epitope. 83. The antigen-binding molecule of embodiment 82, wherein the first and third Fab domains have identical sequences. 84. The antigen-binding molecule of any one of embodiments 75-77, 82, and 83, wherein the second and fourth Fab domains bind to the same epitope. 85. The antigen-binding molecule of embodiment 84, wherein the second and fourth Fab domains have identical sequences. 86. The antigen-binding molecule of any one of embodiments 60-70 and 75-85, which is tetravalent. 87. The antigen-binding molecule of any one of embodiments 1-86, which is an antagonist of the first target molecule. 88. The antigen binding molecule of any one of embodiments 1-87, which inhibits binding of the first target molecule to a binding partner, and optionally, the binding partner is a receptor for the first target molecule. 89. The antigen-binding molecule of any one of embodiments 1-88, wherein the Fc region comprises a human Fc sequence. 90. The antigen-binding molecule of any one of embodiments 1-89, wherein the Fc region comprises a human IgG1 or human IgG4 Fc sequence. 91. The antigen-binding molecule of any one of embodiments 1-90, wherein the Fc region comprises an Fc heterodimer. 92. The antigen binding molecule of embodiment 89, wherein the Fc domain in the Fc heterodimer comprises knobs-in-holes mutations compared to the wild-type Fc domain. 93. The antigen binding molecule of embodiment 92, wherein the Fc domain in the first polypeptide comprises a knob mutation and the Fc domain in the second polypeptide comprises a hole mutation. 94. The antigen binding molecule of embodiment 92, wherein the Fc domain in the second polypeptide comprises a knob mutation and the Fc domain in the first polypeptide comprises a hole mutation. 95. The antigen-binding molecule of embodiment 89, wherein the Fc region comprises a star mutation compared to the wild-type Fc region. 96. The antigen binding molecule of embodiment 89, wherein the Fc domain in the first polypeptide comprises a H435R mutation and a Y436F mutation. 97. The antigen binding molecule of embodiment 89, wherein the Fc domain in the second polypeptide comprises a H435R mutation and a Y436F mutation. 98. The antigen-binding molecule of any one of embodiments 1-97, wherein the CL and CH1 in the first Fab domain are linked by a disulfide bond. 99. The antigen-binding molecule of any one of embodiments 1-98, wherein CL and CH1 in the second Fab domain are linked by a disulfide bond. 100. The antigen-binding molecule of any one of embodiments 1-99, wherein the first Fab domain and the second Fab domain bind to a first target molecule. 101. The antigen-binding molecule of any one of embodiments 1-100, wherein the first target molecule is a small molecule soluble ligand. 102. The antigen-binding molecule of any one of embodiments 1-101, wherein the first target molecule is a cytokine or chemokine. 103. The antigen-binding molecule of any one of embodiments 1-100, wherein the first target molecule is a cell surface protein. 104. The antigen binding molecule of any one of embodiments 1-100 and 103, wherein the first target molecule is a tumor-associated antigen. 105. The antigen-binding molecule of any one of embodiments 1-104, wherein the first target molecule comprises a molecule with a molecular weight of less than 100 kDa excluding post-translational modifications. 106. The antigen-binding molecule of any one of embodiments 1-104, wherein the first target molecule comprises a molecule with a molecular weight of less than 100 kDa including post-translational modifications. 107. The antigen-binding molecule of any one of embodiments 1-104, wherein the first target molecule comprises a molecule with a molecular weight of less than 75 kDa excluding post-translational modifications. 108. The antigen-binding molecule of any one of embodiments 1-104, wherein the first target molecule comprises a molecule with a molecular weight of less than 75 kDa including post-translational modifications. 109. The antigen-binding molecule of any one of embodiments 1-104, wherein the first target molecule comprises a molecule with a molecular weight of less than 60 kDa excluding post-translational modifications. 110. The antigen-binding molecule of any one of embodiments 1-104, wherein the first target molecule comprises a molecule with a molecular weight of less than 60 kDa including post-translational modifications. 111. The antigen-binding molecule of any one of embodiments 1-104, wherein the first target molecule comprises a molecule with a molecular weight of less than 45 kDa excluding post-translational modifications. 112. The antigen-binding molecule of any one of embodiments 1-104, wherein the first target molecule has a molecular weight of less than 45 kDa including post-translational modifications. 113. The antigen-binding molecule of any one of embodiments 1-112, wherein the first target molecule has a molecular weight of at least 5 kDa excluding post-translational modifications. 114. The antigen-binding molecule of any one of embodiments 1-112, wherein the first target molecule has a molecular weight of at least 5 kDa including post-translational modifications. 115. The antigen-binding molecule of any one of embodiments 1-112, wherein the first target molecule has a molecular weight of at least 5 kDa excluding post-translational modifications. 116. The antigen-binding molecule of any one of embodiments 1-112, wherein the first target molecule has a molecular weight of at least 5 kDa including post-translational modifications. 117. The antigen-binding molecule of any one of embodiments 1-112, wherein the first target molecule has a molecular weight of at least 10 kDa excluding post-translational modifications. 118. The antigen-binding molecule of any one of embodiments 1-112, wherein the first target molecule has a molecular weight of at least 10 kDa including post-translational modifications. 119. The antigen binding molecule of any one of embodiments 1-118, wherein the first target molecule is glycosylated. 120. The antigen binding molecule of any one of embodiments 1-118, wherein the first target molecule is aglycosylated. 121. The antigen-binding molecule of any one of embodiments 1-120, wherein the first target molecule is a monomer. 122. The antigen-binding molecule of any one of embodiments 1-120, wherein the first target molecule is a dimer. 123. The antigen-binding molecule of embodiment 122, wherein the first target molecule is a homodimer. 124. The antigen-binding molecule of embodiment 122, wherein the first target molecule is a heterodimer. 125. The antigen-binding molecule of any one of embodiments 1-120, wherein the first target molecule is a trimer. 126. The antigen-binding molecule of embodiment 125, wherein the first target molecule is a homotrimer. 127. The antigen-binding molecule of any one of embodiments 1-120, wherein the first target molecule is a tetramer. 128. The antigen-binding molecule of embodiment 127, wherein the first target molecule is a homotetramer. 129. The antigen-binding molecule of any one of embodiments 1-128, which is monospecific. 130. The antigen-binding molecule of any one of embodiments 1-128, which is bispecific. 131. The antigen-binding molecule of embodiment 130, which is capable of binding to a first epitope and a second epitope on a first target molecule. 132. The antigen-binding molecule of embodiment 131, comprising at least one Fab domain that binds to a first epitope on a first target molecule and at least one Fab domain that binds to a second epitope. 133. The antigen-binding molecule of embodiment 132, which is capable of simultaneously binding to different epitopes on a first target molecule. 134. The antigen-binding molecule of embodiment 130, which is capable of binding to a first target molecule and a second target molecule. 135. The antigen-binding molecule of embodiment 134, comprising at least one Fab domain that binds to a first target molecule and at least one Fab domain that binds to a second target molecule. 136. The antigen-binding molecule of embodiment 135, which is capable of simultaneously binding to a first target molecule and a second target molecule. 137. Lower IC compared to human IgG antibodies containing the first Fab and the second Fab 50 137. The antigen-binding molecule of any one of embodiments 1 to 136, wherein the antigen-binding molecule blocks binding of the target molecule to its receptor. 138. The antigen-binding molecule of any one of embodiments 1-137, which binds to a target molecule with greater affinity than a human IgG antibody comprising the first Fab and the second Fab. 139. A conjugate comprising the antigen-binding molecule of any one of embodiments 1 to 138 and a cytotoxic or cytostatic agent. 140. A pharmaceutical composition comprising the antigen-binding molecule of any one of embodiments 1 to 138 or the conjugate of embodiment 139 and an excipient. 141. A method for treating a subject having a condition associated with abnormal expression or activity of a target molecule, comprising administering to the subject an effective amount of an antigen-binding molecule according to any one of embodiments 1 to 138, a conjugate of embodiment 139, or a pharmaceutical composition of embodiment 140. 142. A method for inhibiting a molecular pathway associated with a target molecule in a subject, comprising administering to the subject an effective amount of an antigen-binding molecule according to any one of embodiments 1 to 138, a conjugate of embodiment 139, or a pharmaceutical composition of embodiment 140. 143. Use of an antigen-binding molecule according to any one of embodiments 1 to 138, a conjugate of embodiment 139, or a pharmaceutical composition of embodiment 140 in the manufacture of a medicament for the treatment of a condition associated with a target molecule bound by an antigen-binding molecule or conjugate present in the antigen-binding molecule, conjugate, or pharmaceutical composition, respectively. 144. A nucleic acid molecule or a plurality of nucleic acid molecules comprising one or more nucleotide sequences encoding the antigen-binding molecule of any one of embodiments 1 to 138. 145. The nucleic acid molecule or molecules of embodiment 144, wherein one or more nucleotide sequences are each operably linked to an expression control sequence. 146. A cell engineered to express the antigen-binding molecule of any one of embodiments 1 to 138. 147. A cell transfected with one or more expression vectors comprising one or more nucleic acid sequences encoding the antigen-binding molecule of any one of embodiments 1 to 138 under the control of one or more promoters. 148. (a) culturing the cells of embodiment 146 or embodiment 147 under conditions in which the antigen-binding molecule is expressed; (b) recovering the antigen-binding molecule from the cell culture. 149. The method of embodiment 148, further comprising concentrating the antigen-binding molecules. 150. The method of embodiment 148 or embodiment 149, further comprising purifying the antigen-binding molecule.

[0295] 8.2. Group B Specific Embodiments 1. (a) a first heavy chain polypeptide, the first heavy chain polypeptide comprising a first CH amino acid sequence, a first VH amino acid sequence, and a second CH amino acid sequence, wherein the first VH amino acid sequence is between the first CH amino acid sequence and the second CH amino acid sequence; (b) a second heavy chain polypeptide comprising a third CH amino acid sequence, a second VH amino acid sequence, and a fourth CH amino acid sequence, wherein the second VH amino acid sequence is located between the third CH amino acid sequence and the fourth CH amino acid sequence. 2. The antigen binding molecule of embodiment 1, wherein the first CH amino acid sequence comprises a first CH3 amino acid sequence positioned N-terminally of the first VH amino acid sequence. 3. The antigen binding molecule of embodiment 2, wherein the first CH3 comprises a H435R mutation and a Y436F mutation. 4. The antigen binding molecule of embodiment 2 or embodiment 3, further comprising a first linker connecting the N-terminus of the first VH amino acid sequence to the C-terminus of the first CH3 amino acid sequence. 5. The antigen-binding molecule of any one of embodiments 1 to 4, wherein the third CH amino acid sequence comprises a second CH3 amino acid sequence located N-terminally of the second VH amino acid sequence. 6. The antigen binding molecule of embodiment 5, further comprising a second linker connecting the N-terminus of the second VH amino acid sequence to the C-terminus of the second CH3 amino acid sequence. 7. The antigen-binding molecule of any one of embodiments 1 to 6, wherein the second CH amino acid sequence comprises a first CH1 amino acid sequence located C-terminal to the first VH amino acid sequence. 8. The antigen-binding molecule of any one of embodiments 1 to 7, wherein the fourth CH amino acid sequence comprises a second CH2 amino acid sequence located C-terminal to the second VH amino acid sequence. 9. The antigen-binding molecule of any one of embodiments 1 to 8, further comprising a first CH2 amino acid sequence located N-terminal to the first CH3 amino acid sequence. 10. The antigen-binding molecule of any one of embodiments 1 to 9, further comprising a second CH2 amino acid sequence located N-terminal to the second CH3 amino acid sequence. 11. The antigen-binding molecule of any one of embodiments 1 to 10, wherein the antigen-binding molecule does not comprise a hinge region disulfide bond. 12. The antigen-binding molecule of any one of embodiments 1-11, further comprising a first light chain polypeptide, wherein the first light chain polypeptide comprises a first VL amino acid sequence, and a first CL amino acid sequence. 13. The antigen-binding molecule of embodiment 12, further comprising a disulfide bond linking the first CL to the first CH1. 14. The antigen-binding molecule of any one of embodiments 1-13, further comprising a second light chain polypeptide, wherein the second light chain polypeptide comprises a second VL amino acid sequence, and a second CL amino acid sequence. 15. The antigen-binding molecule of embodiment 14, further comprising a disulfide bond linking the second CL to the second CH1. 16. The antigen-binding molecule of any one of embodiments 6 to 15, wherein the first linker and the second linker each comprise a polypeptide. 17. The antigen-binding molecule of embodiment 16, wherein the first linker and the second linker have a length of 0 to 50 amino acids. 18. The antigen-binding molecule of any one of embodiments 16-17, wherein the first linker and the second linker have the same amino acid sequence. 19. The antigen-binding molecule of any one of embodiments 16-18, wherein the first linker and the second linker each comprise a polyglycine and a serine amino acid sequence. 20. The antigen-binding molecule of embodiment 19, wherein the polyglycine and serine amino acid sequence comprises 2 to 6 repeating GGGGS (SEQ ID NO: 3) amino acid sequences. 21. The antigen binding molecule of embodiment 20, wherein the polyglycine and serine amino acid sequence comprises (G4S)2 (SEQ ID NO: 18), (G4S)3 (SEQ ID NO: 4), or (G4S)4 (SEQ ID NO: 19). 22. The antigen-binding molecule of any one of embodiments 14-21, wherein the first light chain polypeptide and the second light chain polypeptide have identical amino acid sequences. 23. The antigen-binding molecule of any one of embodiments 1 to 22, wherein the first heavy chain polypeptide and the second heavy chain polypeptide have the same amino acid sequence. 24. The antigen-binding molecule of any one of embodiments 1 to 22, wherein the first heavy chain polypeptide and the second heavy chain polypeptide have non-identical amino acid sequences. 25. Antigen-binding molecules: ABCF1, ACVR1, ACVR1B, ACVR2, ACVR2B, ACVRL1, ADORA2A, Agrican, AGR2, AICDA, AIF1, AIG1, AKAP1, AKAP2, AMH, AMHR2, ANGPT1, ANGPT2, ANGPTL3, ANGPTL4, ANPEP, APC, APOC1, AR, AZGP1 (a-glycan), ART-4, B7, B7.1, B7.2, BAD, BAFF, BAGI, BAIi, BCL2, BCL6, BDNF, BLNK, BLR1 (MDR1S), Bly S, BMP1, BMP2, BMP3B(GDF10), BMP4, BMP6, BMPS, BMPR1A, BMPR1B, BMPR2, BPAG1(プレクチン), BRCA1, Ba-733, BAGE, BrE3-antigen, CA125, CAMEL, CAP-I, CASP-8 / m, CCCL19, CCCL21, CD1, CD1a, CD2, CD3, CD4, CDS, CD8, CDI-IA, CD14, CD15, CD16, CD18, CD19, CD20, CD21, CD22, CD23, CD25, CD29, CD30, CD32b, CD33, CD 37. CD38, CD40, CD40L, CD45, CD46, CD54, CD55, CD59, CD64, CD66a-e, CD67, CD70, CD74, CD79a, CD80, CD83, CD95, CD126, CD133, CD138, CD147, CD154, C DC27, CDK-4 / m, CDKN2A, CXCR4, CXCR7, CXCL12, C19orf10(IL27w), C3, C4A, CS, CSR1, CANT1, CASPI, CASP4, CAV1, CCBP2(D6 / JAB61), CCLI(I-309), CCLI I(エオタキシン), CCL13(MCP-4), CCLIS(MIP-1d), CCL16(HCC-4), CCL17(TARC), CCLIS(PARC), CCL19(MIP-3b), CCL2(MCP-1), MCAF, CCL20(MIP-3a), CCL21 (MIP-2), SLC, エクソダス-2, CCL22(MDC / STC-1), CCL23(MPIF-1), CCL24(MPIF- 2 / エオタキシン-2), CCL2S(TECK), CCL26(エオタキシン-3), CCL27(CTACK / ILC), CCL2S,CCL3(MIP1a)、CCL4(MIP-1b)、CCLS(RANTES)、CCL7(MCP-3)、CCLS(mcp-2)、CCNA1、CCNA2、CCND1、CCNE1、CCNE2、CCR1(CKR1 / HM14S)、CCR2(mcp-1RB / RA)、CCR3(CKR3 / CMKBR3)、CCR4、CCRS(CMKBRSI ChemR13)、CCR6(CMKBR6 / CKR-L3 / STRL22 / DRY6)、CCR7(CKR7 / EB1)、CCRS(CMKBRS / TER1 / CKR-LI)、CCR9(GPR-9-6)、CCRLI(VSHK1)、CCRL2(L-CCR)、CD164、CDlC、CD200、CD-22、CD24、CD2S、CD3S、CD3E、CD3G、CD3Z、CD4、CD44、CD4SRB、CD47、CD4S、CDS2、CD69、CD72、CD79A、CD79B、CDSO、CDS1、CDS3、CDS6、CD137、CD13S、B7-1、B7-2、ICOSL、B7-H3、B7-H4、CD137L、OX40L、CDH1(E-カドヘリン)、CDH10、CDH12、CDH13、CDHlS、CDH19、CDH20、CDHS、CDH7、CDHS、CDH9、CDK2、CDK3、CDK4、CDKS、CDK6、CDK7、CDK9、CDKN1A(p21 Wap1 / Cip1)、CDKN1B(p27Kip1)、CDKN1C、CDKN2A(p16INK4a)、CDKN2B、CDKN2C、CDKN3、CEBPB、CER1、CHGA、CHGB、キチナーゼ、CHST1O、CKLFSF2、CKLFSF3、CKLFSF4、CKLFSFS、CKLFSF6、CKLFSF7、CKLFSFS、CLDN3、CLDN7(クローディン-7)、CLN3、CLU(クラステリン)、CMKLR1、CMKOR1(RDC1)、CNR1、COLISA1、COLIA1、COL4A3、COL6Al、CR2、CRP、CSF1(M-CSF)、CSF2(GM-CSF)、CSF3(GCSF)、CTLA-4、CTNNB1(b-カテニン)、CTSB(カテプシンB)、CX3CLI(SCYD1)、CX3CR1(V2S)、CXCLI(GRO1)、CXCLIO(IP-10)、CXCL11(I-TAC / IP-9)、CXCL13、CXCL14、CXCL16, CXCL2(GR02), CXCL3(GR03), CXCLS(ENA-7S / LIX), CXCL6(GCP-2), CXCL9(MIG), CXCR3(GPR9 / CKR-L2), CXCR6(TYMSTR / STRL33 / Bonzo), CYBS, CYC1, CYSLTR1, HIF-1-a, colon-specific antigen-p (CSAp), CEA (CEACAM5), CEACAM6, c-met, DAB2IP, DES, DKFZp4S1J011S, DNCLI, DPP4, DAM, EGFR, EGFRvl ll, EGP-1, EGP-2, ELF2-M, Ep-CAM, E2F1, ECGF1, EDG1, EFNA1, EFNA3, EFNB2, EGF, EGFR, ELAC2, ENG, EN01, EN02, EN03, EPHB4, EPO, EREG, ERKS, ES R1, ESR2, F3(TF), FADD, FasL, FASN, FCER1A, FCER2, FCGR3A, FGF, FGF1(aFGF), FGF10, FGF11, FGF12, FGF12B, FGF13, FGF14, FGF16, FGF17, FGF1S, FGF19, FGF2 (bFGF), FGF20, FGF21, FGF22, FGF23, FGF3 (int-2), FGF4 (HST), FGFS, FGF7 (KGF), FGFS, FGF9, FGFR3, FIGF (VEGFD), FILI (EPSILON), FILI (ZETA), FLJ12SS4, FLJ2SS30, FLRT1 (fibronectin), FOS, FOSLI (FRA-1), FY (DARC), Flt-I, Flt-3, folate receptor, G250 antigen, GAGE, GROB, GABRP (GABAa) , GAGEB1, GAGEC1, GALNAC4S-6ST, GATA3, GDFS, GFil, GGTl, GM-CSF, GNAS1, GNRH1, GPR2 (CCR10), GPR31, GPR44, GPRS1 (FKSGSO), GRCC10 (C10), GRP, GSN (gelsolin), GSTP1, HAVCR2, HDAC4, HDACS, HDAC7A, HDAC9, HGF, HIP1 histamine and histamine receptor, HLA-A, HLA-DRA, HM74, HMOX1, HUMCYT2A, HLA-DR, HMI 24, human chorionic gonadotropin (HCG) and its subunits, HER2 / neu,HMGB-1, hypoxia-inducible factor (HIF-1), HSP70-2M, HST-2 or 1a, IGF-IR,

number

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[0296] 9. Citation of References All publications, patents, patent applications, and other documents cited in this application are incorporated herein by reference in their entirety for all purposes to the same extent as if each individual publication, patent, patent application, or other document was individually indicated to be incorporated by reference for all purposes. In the event of a conflict between the teachings of this specification and one or more of the references incorporated into this disclosure, the teachings of this specification are intended.

Claims

1. An antigen-binding molecule that binds to a first target molecule having a molecular weight of less than 100 kDa, (a) In the N- to C-terminal orientation (i) a first Fc domain, and (ii) a first polypeptide comprising a first Fab domain comprising, in N to C orientation, a first heavy chain variable region (VH) associated with a first light chain variable region (VL) and a first heavy chain constant region (CH1) associated with a first light chain constant region (CL); (b) in the N- to C-terminal orientation (i) a second Fc domain having a sequence different from the first Fc domain; and (ii) a second polypeptide comprising a second Fab Domain comprising a second VH associated with a second VL and a second CH1 associated with a second CL in N to C orientation; the first Fc domain and the second Fc domain associate with each other to form an Fc region that is an Fc heterodimer; An antigen-binding molecule, wherein the first Fab domain and the second Fab domain can non-competitively access multiple different epitopes on the first target molecule having a molecular weight of less than 100 kDa.

2. The antigen-binding molecule of claim 1, further comprising a first linker between the first Fc domain and the first VH of the first polypeptide and / or a second linker between the second Fc domain and the second VH of the second polypeptide, wherein the first Fab domain and the second Fab domain are flexibly movable to come into close proximity with each other and bind to the plurality of different epitopes on the first target molecule.

3. The antigen-binding molecule described in claim 2, comprising the first linker and the second linker.

4. The antigen-binding molecule of claim 2 or 3, wherein one or both of the first linker and the second linker are 2 to 60 amino acids in length.

5. The antigen-binding molecule of claim 2, wherein the first linker and / or the second linker comprises a multimer of G n S or SG n , where n is an integer of 1 to 7.

6. The antigen-binding molecule of claim 2, wherein the first linker and the second linker both comprise (G4S) n .

7. The antigen-binding molecule of claim 2, wherein the first linker and the second linker have the same amino acid sequence.

8. The antigen-binding molecule of claim 2, wherein the first linker and the second linker have non-identical amino acid sequences.

9. The antigen-binding molecule of any one of claims 1 to 8, which binds to the first target molecule with greater affinity and / or avidity than a native immunoglobulin comprising the first Fab domain and the second Fab domain.

10. The antigen-binding molecule according to any one of claims 1 to 9, wherein the first polypeptide and the second polypeptide comprise a VH only on the C-terminal region side of the first Fc domain and the second Fc domain, respectively.

11. The antigen-binding molecule of claim 1, wherein the first VH and the first CH1, and the second VH and the second CH1 are all arranged in tandem from the N-terminus to the C-terminus.

12. The antigen-binding molecule of any one of claims 1 to 10, wherein the first VL and the second VL are a common light chain, or the first CL and the first CH1 of the first Fab domain, or the second CL and the second CH1 of the second Fab domain, are in a crossmab configuration.

13. The antigen-binding molecule of any one of claims 1 to 12, wherein the first target molecule has a molecular weight of less than 100 kDa excluding post-translational modifications.

14. The antigen-binding molecule of any one of claims 1 to 12, wherein the first target molecule has a molecular weight of less than 100 kDa including post-translational modifications.

15. The antigen-binding molecule of any one of claims 1 to 14, wherein the first target molecule is a low-molecular-weight soluble ligand.

16. The antigen-binding molecule of claim 15, wherein the first target molecule is a cytokine or a chemokine.

17. The antigen-binding molecule of claim 16, which forms a complex with the cytokine in a 1:1 ratio.

18. The antigen-binding molecule of claim 16, wherein the cytokine is thymic stromal lymphopoietin (TSLP), IL-1α, IL-1β, IL-12, IL-18, TNFα, IL-23, IL-13, macrophage migration inhibitory factor (MIF), IL-6, IL-17, IL-20, IL-15, IL-9, IL-4, IL-5, IL-25, TGF-β, or CCL25.

19. The antigen-binding molecule of claim 16, wherein the cytokine is human thymic stromal lymphopoietin (TSLP).

20. The antigen-binding molecule of any one of claims 1 to 19, wherein the first polypeptide comprises at least one hinge domain at the N-terminus and / or C-terminus of the first Fc domain, and the second polypeptide comprises at least one hinge domain at the N-terminus and / or C-terminus of the second Fc domain.

21. The antigen-binding molecule of claim 20, wherein the hinge domain of the first polypeptide and the hinge domain of the second polypeptide are linked via a disulfide bond.

22. The antigen-binding molecule of claim 20, having one hinge region composed of the hinge domain of the first polypeptide and the hinge domain of the second polypeptide.

23. The antigen-binding molecule of claim 22, wherein one of the hinge regions has the amino acid sequence ESKYGPPCPPC or GGGGSCPPC.

24. The antigen-binding molecule of claim 20, having two hinge regions composed of the hinge domain of the first polypeptide and the hinge domain of the second polypeptide.

25. The antigen-binding molecule of claim 24, wherein the two hinge regions both have the amino acid sequence ESKYGPPCPPC.

26. The antigen-binding molecule of claim 22 or 24, wherein the hinge region comprises a chimeric hinge sequence.

27. The antigen-binding molecule of claim 26, wherein the chimeric hinge sequence comprises SEQ ID NO: 22 or SEQ ID NO:

23.

28. The antigen-binding molecule of any one of claims 1 to 27, wherein the first Fab domain and the second Fab domain are not in the form of a single-chain Fab.

29. The antigen-binding molecule of any one of claims 1 to 28, wherein binding of the antigen-binding molecule to the first target molecule inhibits binding of the first target molecule to a binding partner.

30. The antigen-binding molecule of claim 29, wherein the binding partner is a receptor for the first target molecule.

31. The antigen-binding molecule of any one of claims 1 to 30, wherein the Fc region comprises a human Fc sequence.

32. The antigen-binding molecule of claim 31, wherein the human Fc sequence is a human IgG 1 or human IgG 4 Fc sequence.

33. The antigen-binding molecule of claim 32, wherein the human Fc sequence comprises the amino acid sequence of residues 99 to 326 of SEQ ID NO:

31.

34. The antigen-binding molecule of any one of claims 1 to 33, wherein the first Fc domain and the second Fc domain in the Fc heterodimer comprise knobs-in-holes mutations compared to a wild-type Fc domain.

35. (a) the first Fc domain in the first polypeptide comprises a knob mutation and the second Fc domain in the second polypeptide comprises a hole mutation; or (b) the second Fc domain in the second polypeptide comprises a knob mutation, and the first Fc domain in the first polypeptide comprises a hole mutation. The antigen binding molecule of claim 34.

36. The antigen-binding molecule of claim 35, wherein the Fc region comprises a star mutation compared to a wild-type Fc region.

37. Compared to a wild-type Fc region, (a) the first Fc domain in the first polypeptide comprises a H435R mutation and a Y436F mutation; or (b) the second Fc domain in the second polypeptide comprises a H435R mutation and a Y436F mutation, the antigen-binding molecule of claim 36.

38. The antigen-binding molecule of any one of claims 1 to 37, wherein the first target molecule is a cell surface protein.

39. The antigen-binding molecule of claim 38, wherein the first target molecule is a tumor-associated antigen.

40. The antigen-binding molecule of any one of claims 1 to 39, wherein the first target molecule is not glycosylated.

41. The antigen-binding molecule of any one of claims 1 to 40, wherein the first target molecule is a monomer.

42. The antigen-binding molecule of any one of claims 1 to 40, wherein the first target molecule is a dimer.

43. The antigen-binding molecule described in claim 42, wherein the dimer is a homodimer or a heterodimer.

44. The antigen-binding molecule of any one of claims 1 to 40, wherein the first target molecule is (a) a trimer or (b) a tetramer.

45. The antigen-binding molecule described in claim 44, wherein the trimer is a homotrimer.

46. The antigen-binding molecule described in claim 44, wherein the tetramer is a homotetramer.

47. The antigen-binding molecule of any one of claims 1 to 46, wherein the first Fab domain and the second Fab domain are capable of binding to a first epitope and a second epitope on the first target molecule, respectively.

48. The antigen-binding molecule of claim 47, wherein the first Fab domain and the second Fab domain can simultaneously bind to the first epitope and the second epitope on the first target molecule.

49. (a) blocks binding of the first target molecule to a receptor for the first target molecule with a lower IC 50 compared to a human IgG antibody comprising the first Fab domain and the second Fab domain; and / or (b) the antigen-binding molecule according to any one of claims 1 to 48, which binds to the first target molecule with greater affinity than a human IgG antibody comprising the first Fab domain and the second Fab domain.

50. A conjugate comprising the antigen-binding molecule of any one of claims 1 to 49 and a cytotoxic agent or a cytostatic agent.

51. A pharmaceutical composition comprising the antigen-binding molecule of any one of claims 1 to 49 or the conjugate of claim 50, and an excipient.

52. An antigen-binding molecule described in any one of claims 1 to 49, for use in a method for treating a condition associated with abnormal expression or activity of the first target molecule.

53. An antigen-binding molecule described in any one of claims 1 to 49, for use in a method for inhibiting a molecular pathway associated with the first target molecule.

54. A nucleic acid molecule or multiple nucleic acid molecules comprising one or multiple nucleotide sequences encoding the antigen-binding molecule of any one of claims 1 to 49.

55. A nucleic acid molecule or multiple nucleic acid molecules described in claim 54, wherein one or more of the nucleotide sequences are all operably linked to an expression control sequence.

56. A cell engineered to express an antigen-binding molecule described in any one of claims 1 to 49.

57. A method for producing the antigen-binding molecule of any one of claims 1 to 49, comprising: (a) culturing the cell according to claim 56 under conditions in which the antigen-binding molecule is expressed; (b) recovering the antigen-binding molecule from the cell culture.

58. The method of claim 57, further comprising one or both of concentrating the antigen-binding molecule and purifying the antigen-binding molecule.

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