Keymed Biosciences Inc. announced that Lei Zhang's team from the Institute of Hematology, Chinese Academy of Medical Sciences has recently published a research paper titled "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, exploratory clinical study to evaluate the safety and preliminary efficacy of CM313 in adult patients with primary immune thrombocytopenia. 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 x 109/L within 8 weeks upon the first acceptance of CM313 infusion, with a median cumulative duration for a platelet count of 50x 109/L of 23 weeks (interquartile range: 17 to 24). The median time to first platelet count of 50 x 110/L was 1 week (range: 1-3), and the median time to first platelet counts of 30 x 109/L with a 2-fold increase from baseline was 1 week.

Additionally, the durable sustained platelet count response rate (defined as platelet count of 50 x109/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 primary immune thrombocy topenia patients who had previously received multiple therapies. Safety analyses showed that CM313 was well-tolerated. CM313 is a humanized monoclonal antibody that targets CD38 and the first domestically- developed CD38 antibody with investigational new drug (IND) approval by the National Medical Products Administration (NMPA) in China.

Results from a phase I clinical study of relapsed/refractory multiple myeloma and lymphoma demonstrated a favorable safety profile of CM313 and preliminary efficacy at dose levels of 2.0 mg/kg in patients with relapsed/refractory multiple myeloma. In an investigator-initiated exploratory clinical study evaluating CM313 for the treatment of primary immune thrombocytopenia in adults, patients achieved an overall response throughout the study. Currently, a phase Ib/IIa clinical study of CM313 for the treatment of systemic lupus erythematosus is ongoing.