IGM Biosciences has announced the discontinuation of its autoimmune programs, halting the development of imvotamab (an IgM-based CD20 X CD3 bispecific antibody T cell engager) and IGM-2644 (an IgM-based CD38 X CD3 bispecific antibody T cell engager). This decision follows interim data from Phase 1b studies of imvotamab in patients with rheumatoid arthritis and systemic lupus erythematosus (SLE) that showed inadequate B cell depletion. The company is also implementing a 73% workforce reduction to conserve capital and explore strategic options.
Disappointing Trial Data
The Phase 1b trials aimed to assess the efficacy of imvotamab in depleting B cells, a key therapeutic goal in autoimmune diseases like rheumatoid arthritis and SLE. However, the interim data revealed that the "depth and consistency of B cell depletion" did not meet IGM Biosciences' internal benchmarks for success, according to CEO Mary Beth Harler. Consequently, the company decided to terminate the imvotamab program.
Strategic Shift and Financial Impact
Concurrent with the discontinuation of imvotamab, IGM Biosciences is also ceasing development of IGM-2644 due to strategic considerations. This move represents a significant shift for the company, which had previously focused on developing antibody drugs for cancer before pivoting to autoimmune disease research in 2024. As of December 31, 2024, IGM Biosciences reported approximately $183.8 million in cash and investments. The company's stock value has experienced a sharp decline following the announcement.
Workforce Reduction
To preserve cash resources, IGM Biosciences is reducing its workforce by approximately 73%. This restructuring will allow the company to evaluate internal options and explore potential strategic alternatives, which could include a sale or merger with a privately held partner. Mary Beth Harler expressed gratitude to the departing employees for their contributions to the company's programs.
Bispecific Antibody Approach
Imvotamab and IGM-2644 are both IgM-based bispecific antibodies designed to engage T cells and target B cell surface proteins. Imvotamab targets CD20, while IGM-2644 targets CD38, both of which are expressed on B cells. The bispecific antibody approach aims to provide a more practical and effective treatment option for autoimmune diseases. However, the Phase 1b results for imvotamab did not demonstrate the desired level of B cell depletion, leading to the program's termination.
Broader Context
IGM's shift towards autoimmune disease research reflected a broader trend in the biotech industry, driven by promising academic data on cellular medicines for inflammatory conditions. While some analysts had expressed optimism about imvotamab's potential, the clinical data did not support these expectations. The company will now reassess its strategic direction and explore alternative options to maximize shareholder value.
