NON-PLATELET DEPLETING AND NON-RED BLOOD CELL DEPLETING CD47 ANTIBODIES AND METHODS OF USE THEREOF
This invention relates generally to monoclonal antibodies that recognize CD47, more specifically to CD47 antibodies that do not cause a significant level of agglutination of cells, red blood cell depletion, anemia, and/or platelet depletion, to methods of generating these antibodies, and to methods of using these monoclonal antibodies as therapeutics.
1 . A method of treating a hematological cancer in an individual, comprising administering a humanized monoclonal antibody that binds to human CD47, wherein the antibody binds to a discontinuous epitope on CD47 comprising a CD47 loop comprising the amino acid sequence set forth in SEQ ID NO: 56 and amino acid residues Y37, T102 and E104 of CD47 when numbered in accordance with SEQ ID NO: 147, and wherein the antibody does not cause a significant level of agglutination of red blood cells.
2 . The method of claim 1 , wherein the antibody does not cause a significant level of agglutination of red blood cells in a 10% red blood cell solution.
3 . The method of claim 1 , wherein the antibody promotes macrophage-mediated phagocytosis of a CD47-expressing cell.
4 . The method of claim 1 , wherein the antibody prevents CD47 from interacting with signal-regulatory-protein α (SIRPct).
5 . The method of claim 1 , wherein the discontinuous epitope comprises Y37, K9, K4 K43, G44, R45, D46, D51, H90, N93, E97, T99, T102, E104, and E106 of CD47 when numbered in accordance with SEQ ID NO: 147.
6 . The method of claim 1 , wherein the antibody comprises one or more amino acid substitutions in a human IgG constant region that result in a reduced FcγR binding affinity as compared to a corresponding anti-CD47 antibody with a wildtype human IgG1 isotype, wherein the antibody causes a reduced level of platelet depletion after administration as compared to the corresponding anti-CD47 antibody with a wildtype human IgG1 isotype.
7 . The method of claim 1 , wherein the antibody comprises one or more amino acid substitutions in a human IgG constant region comprising the amino acid sequence set forth in any of SEQ ID NOs: 1-4.
8 . The method of claim 6 , wherein the antibody is a human IgG1 isotype.
9 . The method of claim 6 , wherein the antibody is a human IgG4 isotype.
10 . The method of claim 8 , wherein the one or more amino acid substitutions comprise a S228P mutation.
11 . The method of claim 8 , wherein the one or more amino acid substitutions comprise a L235E mutation.
12 . The method of claim 6 , wherein the FcγR is FcγRI.
13 . The method of claim 6 , wherein the FcγR is FcγRIIIa.
14 . The method of claim 1 , wherein the antibody binds to CD47 in a head to side orientation, wherein a VH chain of the antibody is positioned near the membrane of a CD47 expressing cell, and wherein a VL chain of the antibody occludes a SIRPα binding site on CD47.
15 . The method of claim 1 , wherein the antibody binds to CD47 in a head to side orientation, wherein a VL chain of the antibody is positioned near the membrane of a CD47 expressing cell, and wherein a VH chain of the antibody occludes a SIRPα binding site on CD47.
16 . The method of claim 1 , wherein the hematological cancer is a lymphoma or leukemia.
17 . The method of claim 1 , wherein the antibody is administered to the subject at a dose of at least 10 mg/kg.
18 . The method of claim 17 , wherein the antibody is administered to the subject at a dose of at least 30 mg/kg.
19 . The method of claim 1 , wherein the subject is a human.
20 . The method of claim 1 , further comprising administering a second agent or therapy.