C4 Therapeutics, Inc. has announced the results from its Phase 1 clinical trial of cemsidomide, an orally bioavailable IKZF1/3 degrader, in combination with dexamethasone for the treatment of relapsed/refractory multiple myeloma. These results were presented at the International Myeloma Society Annual Meeting. The trial demonstrated a 50% overall response rate at the highest cemsidomide dose level of 100 µg, and a 40% response rate at the 75 µg dose level in a heavily pre-treated patient population. The median duration of response was reported as 9.3 months across dose levels, though it has not been reached at the two highest doses. The safety profile was favorable, with no discontinuations related to cemsidomide and few dose reductions. Upcoming milestones include aligning with the FDA on the Phase 2 dose recommendation by the end of 2025 and initiating further trials in 2026.