CStone's CS2009 shows promise in clinical trials

CStone Pharmaceuticals announced positive clinical progress for its CS2009, a PD-1/VEGF/CTLA-4 trispecific antibody, currently undergoing a global multicenter Phase I/II study. The Phase Ia dose escalation has evaluated four dose levels in patients with advanced solid tumors and has just passed safety evaluation by the Safety Monitoring Committee without identifying any Dose Limiting Toxicity (DLT) at 20mg/kg Q3W. Enrollment is proceeding quickly, and the trial is expected to exceed 100 patients by the end of the year. Preliminary data shows CS2009 is well-tolerated across all evaluated dose levels, exhibiting excellent pharmacokinetic profiles and pharmacodynamic responses, indicating T cell activation. Anti-tumor activities have been observed in patients with “cold” tumors and PD-(L)1 pretreated tumors. Phase Ia data is targeted for presentation at an international conference in Q4 2025. Phase Ib/II dose expansion/pivotal extension studies are anticipated to commence in the second half of 2025.