Promising safety and efficacy data for novel anti-CD38 treatment in ITP

The investigational anti-CD38 therapy CM313 was associated with rapid and durable improvements in platelet levels in adult patients with immune thrombocytopenia (ITP). According to the researchers, the safety profile was favourable, suggesting that this agent may become a valuable treatment option for the population.

Prof. Yanmei Xu (Peking Union Medical College, China) and co-investigators conducted a randomised-controlled phase 2 trial to compare the anti-CD38 monoclonal antibody CM313 with placebo in 45 patients with persistent or chronic primary ITP who had previously received glucocorticoid treatment and had responded to standard first-line therapy. Patients received weekly intravenous CM313 (16 mg/kg) or placebo for 8 weeks  [1]. Prof. Xu mainly reported on improvements in platelet counts, bleeding, and safety.

At week 8, 83% of the participants in the experimental arm and 20% of those in the placebo arm had achieved the primary endpoint, which was defined as ‘at least 2 consecutive platelet counts ≥30x10⁹/L, representing a doubling from baseline, in the absence of bleeding’. Moreover, the median time to attain a platelet count ≥50x10⁹/L in the active arm was 1 week. Prof. Xu emphasised that the median cumulative duration of a platelet count ≥50x10⁹/L was 18 weeks in the CM313 group and 3 weeks in the placebo group. In the CM313 arm, the bleeding rate had decreased from 37% at baseline to 13% at week 24, whereas this rate had increased from 27% to 33% in the placebo arm. Finally, Prof. Xu mentioned that treatment-emergent adverse event rates were around 80% in both groups. Infusion reactions were more common in the experimental arm (30% vs 13%), but petechiae were more frequently observed in the placebo group (27% vs 67%). The rates of upper respiratory tract infection were 13% in both groups.

“This experimental anti-CD38 targeted therapy rapidly boosted platelet levels by inhibiting antibody-dependent cell-mediated cytotoxicity on platelets,” concluded Prof. Xu. “The responses were durable due to a clearing of plasma cells.” The efficacy and safety results of CM313 are promising and warrant further testing in larger ITP populations and comparing it against approved second-line therapies.

1. Xu Y, et al. Safety and efficacy of CM313 in adults with immune thrombocytopenia: a randomized, placebo-controlled trial. LB4004, EHA2025 Congress, 12–15 June, Milan, Italy.

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Posted on 2 September 20252 September 2025