Imvotamab, a CD20 x CD3 bispecific monoclonal antibody, offers potential for deeper B cell depletion than currently approved therapies

MOUNTAIN VIEW, CA, USA I May 31, 2023 I IGM Biosciences, Inc. (Nasdaq: IGMS), a clinical-stage biotechnology company focused on creating and developing IgM antibodies, today announced that the U.S. Food and Drug Administration (FDA) has cleared two Investigational New Drug (IND) applications for imvotamab, an IgM-based CD20 X CD3 bispecific antibody T cell engager, enabling the initiation of Phase 1b studies in both severe systemic lupus erythematosus (SLE) and severe rheumatoid arthritis (RA). The Company plans to begin patient enrollment in both multicenter clinical studies in the third quarter of 2023.

“Treating autoimmune disease with T cell engagers is an exciting new field of therapeutic research, and we believe imvotamab, with its potential for deep B cell depletion, offers the opportunity to lead and transform treatment in this area,” said Mary Beth Harler, M.D., President, IGM Autoimmunity and Inflammation. “Over the last two decades, CD20 has become well-established as a therapeutic target in multiple autoimmune diseases. The data from our non-Hodgkin’s lymphoma clinical studies indicate that imvotamab can deplete CD20 expressing B cells, even rapidly growing lymphoma cells, with a favorable safety profile as compared with other T cell engaging CD20 x CD3 antibodies. Emerging data with cell-based therapies suggest that deep B cell depletion may have the potential to reset the immune system in patients with certain autoimmune diseases. We look forward to initiating these Phase 1b clinical trials for patients with SLE and RA in the third quarter of 2023 and fully developing the potential of imvotamab and other IgM based T cell engagers in autoimmune diseases.”

The primary outcome measure of the Phase 1b SLE and RA clinical trials will be the safety, tolerability, pharmacokinetics, pharmacodynamics and biologic activity of imvotamab in patients with severe SLE and severe RA who have failed multiple prior therapies. In preclinical in vivo studies, imvotamab has demonstrated deep B cell depletion within tissues, where depletion of pathogenic immune cells may be critical to long-term clinical benefit in autoimmune diseases. Imvotamab has also demonstrated in preclinical in vitro studies that it can be more effective in depleting B cells with low levels of CD20 expression as compared to rituximab. Further, recently reported results from the Company’s Phase 1 and Phase 2 non-Hodgkin’s lymphoma (NHL) studies demonstrated an incidence of cytokine release syndrome (CRS) that was lower than the rates of CRS reported for other T cell engaging bispecific CD20 x CD3 antibodies in comparable NHL clinical studies.

About Imvotamab (IGM-2323)
Imvotamab is a novel IgM-based CD20 x CD3 bispecific antibody T cell engager (TCE). Preclinical research demonstrates that imvotamab may have advantages over IgG bispecific antibodies including greater binding power to CD20 expressing cells especially when CD20 expression levels are low.

About IGM Biosciences, Inc.
IGM Biosciences is a clinical-stage biotechnology company committed to developing and delivering a new class of medicines to treat patients with cancer, autoimmune and inflammatory diseases and infectious diseases. The Company’s pipeline of clinical and preclinical assets is based on the IgM antibody, which has 10 binding sites compared to conventional IgG antibodies with only 2 binding sites. The Company also has an exclusive worldwide collaboration agreement with Sanofi to create, develop, manufacture, and commercialize IgM antibody agonists against oncology and immunology and inflammation targets. For more information, please visit

SOURCE: IGM Biosciences