C4 Therapeutics presented further analysis from its fully enrolled Phase 1 trial of cemsidomide for relapsed/refractory multiple myeloma (RRMM) at the European Hematology Association (EHA) 2026 Congress. The data highlighted a favorable efficacy and safety profile in a heavily pretreated patient population, supporting the drug's potential as a foundational therapy.
Key Details
- Efficacy: At the 100 µg recommended Phase 2 dose (RP2D), cemsidomide combined with dexamethasone demonstrated a 53% overall response rate (ORR). The ORR was 40% at the 75 µg dose and 36% across all doses.
- Durability & Deepening Response: The median duration of response was 7.9 months. Responses were observed to deepen over time, with two patients at the 100 µg dose achieving minimal residual disease (MRD) negative status.
- Safety Profile: The treatment was well-tolerated, with only 7% of patients (5 of 73) requiring dose reductions due to adverse events. No discontinuations were deemed related to cemsidomide.
- Patient Population: The trial enrolled a heavily pretreated population that had received a median of seven prior lines of therapy, with 75% having received prior CAR-T or T-cell engager therapy.