Multispecific antigen-binding molecules for cell targeting and uses thereof
The present invention provides multispecific antigen-binding molecules that bind both a T-cell antigen (e.g., CD3) and a target antigen (e.g., a tumor associated antigen, a viral or bacterial antigen), and which include a single polypeptide chain that is multivalent (e.g., bivalent) with respect to T-cell antigen binding, and uses thereof.
1. A multispecific antigen-binding molecule, comprising:
(a) a first polypeptide comprising, from N-terminus to C-terminus (i) a first antigen-binding domain that specifically binds human CD3, wherein the first antigen-binding domain comprises an immunoglobulin Fab domain comprising a heavy chain variable region (HCVR) and a heavy chain CH1 domain paired with a light chain variable region (LCVR) and a light chain CL domain; (ii) a first multimerizing domain comprising an immunoglobulin Fc domain; and (iii) a second antigen-binding domain that specifically binds human CD3, wherein the second antigen-binding domain is a single chain variable fragment (scFv) domain comprising a HCVR and a LCVR connected by a peptide linker; and
(b) a second polypeptide comprising, from N-terminus to C-terminus (i) a third antigen-binding domain that specifically binds a target antigen, wherein the third antigen-binding domain comprises an immunoglobulin Fab domain comprising a HCVR and a heavy chain CH1 domain paired with a LCVR and a light chain CL domain; (ii) a second multimerizing domain comprising an immunoglobulin Fc domain; and (iii) a fourth antigen-binding domain that specifically binds a target antigen, wherein the fourth antigen-binding domain is a scFv domain comprising a HCVR and a LCVR connected by a peptide linker,
wherein the first and the second multimerizing domains associate with one another to form the molecule.
2. The molecule of claim 1 , wherein the peptide linker is from 10 to 30 amino acids.
3. The molecule of claim 1 , wherein the peptide linker is a (G4S) n linker, wherein n is from 1 to 10, selected from the group consisting of SEQ ID NOs: 171, 172, 173, 174, 175, 176, 177, 178, 179, and 180.
4. The molecule of claim 1 , wherein the scFv domains comprise a HCVR comprising a cysteine mutation at residue 44 according to Kabat numbering, and a LCVR comprising a cysteine mutation at residue 100 according to Kabat numbering.
5. The molecule of claim 1 , wherein the scFv domains are connected to the C-terminus of the first and second multimerizing domains, respectively, via a linker of from 5 to 25 amino acids.
6. The molecule of claim 1 , wherein the scFv domains are connected to the C-terminus of the first and second multimerizing domains, respectively, via a linker of from 10 to 30 amino acids.
7. The molecule of claim 1 , wherein the scFv domains are connected to the C-terminus of the first and second multimerizing domains, respectively, via a (G4S) n linker, wherein n is 1-10, selected from the group consisting of SEQ ID NOs: 171, 172, 173, 174, 175, 176, 177, 178, 179, and 180.
8. The molecule of claim 7 , wherein the linker is a (G4S) 3 linker consisting of the amino acid sequence of SEQ ID NO: 173.
9. The molecule of claim 3 , wherein the peptide linker is a (G4S) 4 linker consisting of the amino acid sequence of SEQ ID NO: 174.
10. The molecule of claim 1 , wherein each antigen-binding domain that specifically binds human CD3 comprises a HCVR comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 34, SEQ ID NO: 138, and SEQ ID NO: 154.
11. The molecule of claim 1 , wherein the first and second multimerizing domains associate with one another via disulfide bonding.
12. The molecule of claim 1 , wherein the first multimerizing domain and the second multimerizing domain are human IgG1 Fc domains.
13. The molecule of claim 1 , wherein the first multimerizing domain and the second multimerizing domain are human IgG4 Fc domains.
14. The molecule of claim 1 , wherein the first multimerizing domain or the second multimerizing domain, but not both the first multimerizing domain and the second multimerizing domain, comprises an amino acid substitution that reduces affinity for Protein A binding compared to a wild-type Fc domain of the same isotype.
15. The molecule of claim 14 , wherein the amino acid substitution comprises an H435R modification according to EU numbering, or H435R and Y436F modifications according to EU numbering.
16. The molecule of claim 15 , wherein the first multimerizing domain comprises the H435R and Y436F modifications.
17. The molecule of claim 1 , wherein the first polypeptide, the second polypeptide, or both the first and the second polypeptides comprise a modified hinge domain that reduces binding affinity for an Fcγ receptor relative to a wild-type hinge domain of the same isotype.
18. The molecule of claim 1 , wherein the target antigen is a peptide complexed with a major histocompatibility complex (MHC) protein.
19. The molecule of claim 1 , wherein the target antigen is present at a density of from 100 to 5000 copies per target cell.
20. The molecule of claim 1 , wherein the target antigen is a tumor-cell antigen.
21. The molecule of claim 1 , wherein the target antigen is a viral antigen, a bacterial antigen, a fungal antigen, or an antigen expressed by a parasite.
22. The molecule of claim 1 , wherein the target antigen bound by the third antigen-binding domain is different from the target antigen bound by the fourth antigen-binding domain.
23. The molecule of claim 22 , wherein the target antigens bound by the third antigen-binding domain and the fourth antigen-binding domain are co-expressed on a cell surface.
24. The molecule of claim 1 , wherein the target antigen bound by the third antigen-binding domain is the same as the target antigen bound by the fourth antigen-binding domain.