Keymed Biosciences Inc. announced that the latest data from the Phase I clinical study of CM313 (a humanized monoclonal antibody targeting CD38), a Class I innovative drug developed by the Company, for the treatment of relapsed/refractory multiple myeloma (RRMM) and relapsed/refractory lymphoma were presented as a poster presentation at the 28th European Hematology Association (EHA) Congress 2023. This Phase I study (NCT04818372) aimed to evaluate the safety and preliminary efficacy of CM313 in patients with RRMM and relapsed/refractory lymphoma (currently limited to Waldenstrom's macroglobulinemia and marginal zone lymphoma (MZL). As of October 10, 2022, a total of 34 patients (31 RRMM and 3 MZL) were enrolled in the study.

In safety assessments, CM313 was well-tolerated. The dose was successfully escalated up to 16.0 mg/kg, and maximum tolerated dose was not reached. No dose-limiting toxicity was observed.

The most common treatment-related adverse events (occurring in =20% of patients) were infusion-related reactions and decreased cell counts in lymphocytes, white blood cells and neutrophils. All infusion-related reactions were grade 1 or 2 and occurred during the first and/or second infusions. Among the 29 RRMM patients who had at least one post-baseline efficacy evaluation, the overall response rate (ORR) was 34.5%.

The median progression-free survival (PFS) was 132 days, and the median overall survival (OS) was not reached. CM313 exhibited a tolerable and manageable safety profile in general in this study. Moreover, CM313 at dose levels of =2.0 mg/kg yielded preliminary efficacy in patients with RRMM.