- C4 Therapeutics (C4T) presented positive Phase 1 clinical trial data for **cemsidomide** in combination with dexamethasone for relapsed/refractory multiple myeloma (RRMM) at the International Myeloma Society (IMS) Annual Meeting on **September 20, 2025**.  **[1662579_0001628280-25-042245_cccc-20250920xexx991.htm:0]** **[1662579_0001628280-25-042245_cccc-20250920xexx991.htm:1]** 
- The trial demonstrated a **50% Overall Response Rate (ORR)** at the highest dose level (100 µg) and a **40% ORR** at the 75 µg dose level in heavily pre-treated RRMM patients, with a median Duration of Response (DOR) of **9.3 months** across all dose levels.  **[1662579_0001628280-25-042245_cccc-20250920xexx991.htm:0]** **[1662579_0001628280-25-042245_cccc-20250920xexx991.htm:2]** 
- Cemsidomide exhibited a favorable safety profile with **no discontinuations related to the drug** and few dose reductions, supporting its suitability for combination regimens.  **[1662579_0001628280-25-042245_cccc-20250920xexx991.htm:0]** **[1662579_0001628280-25-042245_cccc-20250920xexx991.htm:2]** 
- C4T plans to initiate a Phase 2 registrational trial in **Q1 2026** and a Phase 1b trial in **Q2 2026**, pursuing two distinct accelerated approval pathways for cemsidomide in RRMM.  **[1662579_0001628280-25-042245_cccc-20250920xexx991.htm:3]** 
- The company projects a potential **$2.5 billion to $4 billion peak revenue opportunity** for cemsidomide across these two market segments.  **[1662579_0001628280-25-042245_cemsi_imsinvestorpresent.htm:4]** **[1662579_0001628280-25-042245_cemsi_imsinvestorpresent.htm:16]**

C4 Therapeutics (CCCC)