Engineered antibodies and methods of treatment

Abstract

The invention is related to CD20 antibodies with improved characteristics. Some embodiments describe antibodies comprising a mouse IgG2; a human IgG1, IgA1 or IgA2 constant region and a variable domain that can bind the epitope “EPANpSEK” on human CD20 expressed on Ramos cells and which antibody has an increased PCD functionality when compared to Rituximab with a constant region of the same isotype.

1 .- 15 . (canceled) 
     
     
         16 . A method of treating an FcγRIIb-expressing cancer in a subject, the method comprising administering to the subject a composition that comprises an engineered monomeric IgA antibody in an amount sufficient to treat the FcγRIIb-expressing cancer in the subject,
 wherein the monomeric IgA antibody comprises an IgA heavy chain constant region, and does not comprise any IgG constant region domain; and 
 wherein the monomeric IgA antibody induces caspase-independent programmed cell death (PCD) of FcγRIIb-expressing cancer cells to a great extent relative to caspase-independent programmed cell death (PCD) of FcγRIIb-expressing cancer cells induced by a corresponding IgG antibody that has the same variable region complementarity determining regions (CDRs) as the engineered monomeric IgA antibody, as determined in an in vitro assay comprising:
 (i) contacting a first population of cancer cells that express FcγRIIb with the engineered monomeric IgA antibody, 
 (ii) contacting a second population of cancer cells that express FcγRIIb with the corresponding IgG antibody, 
 (iii) contacting the first population of cancer cells and the second population of cancer cells with Annexin V, and 
 (iv) comparing an amount of fluorescence exhibited by the first population of cancer cells and the second population of cancer cells using a FACS cell sorter, wherein a greater amount of fluorescence indicates a greater amount of PCD. 
 
 
     
     
         17 . The method of  claim 16 , wherein the engineered monomeric IgA antibody is an IgA1 antibody. 
     
     
         18 . The method of  claim 16 , wherein the engineered monomeric IgA antibody is an IgA2 antibody. 
     
     
         19 . The method of  claim 16 , wherein the FcγRIIb-expressing cancer is resistant to the corresponding IgG antibody. 
     
     
         20 . The method of  claim 16 , wherein the IgA heavy chain constant region comprises 1-5 substitutions, insertions, or deletions, relative to the amino acid sequence of SEQ ID NO:4. 
     
     
         21 . The method of  claim 16 , wherein the IgA heavy chain constant region comprises 1-5 substitutions, insertions, or deletions, relative to the amino acid sequence of SEQ ID NO:5. 
     
     
         22 . The method of  claim 16 , wherein the IgA heavy chain constant region comprises an IgA2 hinge. 
     
     
         23 . The method of  claim 16 , wherein the engineered monomeric IgA antibody induces antibody-dependent cell-mediated cytotoxicity (ADCC) of the cancer cell. 
     
     
         24 . The method of  claim 23 , wherein the engineered monomeric IgA antibody facilitates increased ADCC of the cancer cell, relative to the corresponding IgG antibody. 
     
     
         25 . The method of  claim 16 , wherein the engineered monomeric IgA antibody induces antibody-dependent cell-mediated phagocytosis (ADCP) of the cancer cell. 
     
     
         26 . The method of  claim 16 , wherein the PCD is neutrophil-mediated PCD. 
     
     
         27 . The method of  claim 16 , wherein the PCD is macrophage-mediated PCD. 
     
     
         28 . The method of  claim 16 , wherein the engineered monomeric IgA antibody binds to FcαRI. 
     
     
         29 . The method of  claim 16 , wherein the engineered monomeric IgA antibody binds to an antigen selected from the group consisting of: CD20, EGFR, and Her2. 
     
     
         30 . The method of  claim 16 , wherein the FcγRIIb-expressing cancer is a solid tumor cancer. 
     
     
         31 . The method of  claim 16 , wherein the FcγRIIb-expressing cancer is lymphoma. 
     
     
         32 . The method of  claim 16 , wherein the subject is a human. 
     
     
         33 . The method of  claim 16 , wherein the subject is a child.