Background：Ocaratuzumab, previously known as AME-133v, is a humanized IgG1 type monoclonal antibody targeted at CD20 antigen, which is expressed on B-lymphocytes. Ocaratuzumab is a novel Fc-engineered monoclonal antibody designed by Applied Molecular Evolution in an attempt to induce effective antibody-dependent cell-mediated cytotoxicity ADCC at very low concentrations that may facilitate sub-cutaneous dosing. Libraries of antibody Fab fragment regions were generated with codon substituted variations of the antibody complementarity determining regions CDRs inserted into human antibody light and heavy chain germline frameworks. Then, the researchers expressed and selected mutants based on increased affinity for CD20. A variable region with increased binding activity for CD20 was selected and developed as ocaratuzumab. This drug is currently being developed by Mentrik Biotech and has been investigated in the trial for the treatment of cancer and autoimmune disorders. The pre-clinical trials of ocaratuzumab in follicular lymphoma was conducted in the United States US and Japan in phase I/II, and a Phase I trial was conducted in US rheumatoid arthritis patients. In addition, a phase III trial in relapsed follicular lymphoma patients is underway. Compared to rituximab, ocaratuzumab was shown to ocaratuzumab was shown to have 13 to 20 fold greater affinity for CD20 and 6 fold more potent ADCC in pre-clinical studies. The use of ocaratuzumab in other oncology and rheumatology indications has also been developed.
