CHENGDU, China,June 20, 2024 -- Keymed Biosciences Inc. (HKEX: 02162) today announced that Lei Zhang/Renchi Yang’s team from the Institute of Hematology, Chinese Academy of Medical Sciences has recently published a research paper entitled “A Novel Anti-CD38 Monoclonal Antibody for Treating Immune Thrombocytopenia” in the New England Journal of Medicine. This is an investigator-initiated, single-arm, open-label phase I/II study evaluating the safety and preliminary efficacy of CM313 in adult patients with primary ITP.

A total of 22 patients were enrolled in the study, with one patient dropping out after the first infusion. The remaining 21 patients completed both the 8-week treatment and 16-week follow-up periods. Results showed that 95.5% of patients (21/22) achieved a platelet count of ≥50 × 109/L during the 8-week treatment period, with a median cumulative response duration of 23 weeks (interquartile range, 17 to 24). The median time to first platelet count of ≥50 × 109/L was 1 week (range: 1-3), and the median time to first platelet count of ≥30 × 109/L with a ≥2-fold increase from baseline was 1 week. Additionally, the durable sustained platelet count response rate (defined as a platelet count of ≥50 × 109/L observed six or more times among the final eight platelet counts) was 63.6% (14/22). Throughout the entire study, overall response (complete or partial response) was observed in 21 patients, with 20 patients achieving complete response.  The proportion of patients with bleeding decreased from 68.2% (15/22) at baseline to 4.8 (1/21) at week 8. Most patients discontinued concomitant medications due to the restoration of platelet counts to normal or safe levels with CM313 treatment. In summary, CM313 demonstrated rapid and sustained efficacy in 95.5% of ITP patients who had previously received multiple therapies. Safety analyses showed that CM313 was well-tolerated.

CM313 is a humanized monoclonal antibody targeting CD38 and the first domestically-developed anti-CD38 antibody with IND approval by the NMPA in China. Previous phase I/II studies have demonstrated the favorable safety profile and encouraging efficacy of CM313 in patients with RRMM and primary ITP. In addition, the potential use of CM313 in SLE is currently under clinical development.