C4 Therapeutics Sets Up New Combination Trial in Multiple Myeloma: What Investors Should Watch

C4 Therapeutics, Inc. (CCCC) announced an update on their ongoing clinical study.

C4 Therapeutics Advances Early Multiple Myeloma Study Pairing Cemsidomide With Elranatamab

The new Phase 1b study, titled “A Phase 1B, Open-label, Multicenter Study to Evaluate the Safety and Preliminary Efficacy of Cemsidomide in Combination With Elranatamab in Relapsed/Refractory Multiple Myeloma Subjects,” aims to test how safe and tolerable this drug combination is for patients whose multiple myeloma has come back or stopped responding to prior treatment. For investors, the significance lies in whether the combo can show enough early benefit and a manageable safety profile to justify larger, later-stage trials in a crowded but high-value myeloma market.

The study tests an oral small-molecule drug, cemsidomide, together with a biologic injection, elranatamab. Cemsidomide is designed to help the body remove certain proteins that drive myeloma cell growth, while elranatamab is an antibody that redirects the immune system to attack myeloma cells. The goal of combining them is to boost anti-cancer activity in patients who have already exhausted standard options.

The trial is an interventional Phase 1 study, focused mainly on treatment rather than prevention or diagnosis. It uses a non-randomized, open-label design, meaning all participants receive the cemsidomide plus elranatamab regimen and both doctors and patients know what is being given. Doses of cemsidomide will be tested in sequence to find a safe level, and once that is set, more patients will be added at that dose to gather additional safety and early effectiveness data.

Key timing points matter for investors. The study is listed as “not yet recruiting,” with initial submission on December 1, 2025, signaling that site set-up and regulatory steps are underway but patient dosing has not started. The last update was filed on January 9, 2026, showing the program is active in planning and has not been shelved. Primary completion and overall completion dates are not yet specified, which is common at this stage but implies that any meaningful efficacy readouts remain a multi-year event.

From a market view, this update reinforces C4 Therapeutics’ push into multiple myeloma, an area where big players like Bristol Myers Squibb, Johnson & Johnson, and Pfizer are already entrenched with cell therapies, bispecifics, and other novel agents. Any hint that cemsidomide can enhance the activity of a BCMA-directed drug like elranatamab could support a higher strategic value for C4’s platform, potentially lifting sentiment around future partnerships or licensing deals. However, as an early, non-randomized safety study, it is unlikely to move CCCC shares on fundamentals in the near term; instead, it adds to the company’s optionality and narrative in protein degradation and combination strategies. Investors should view this as a long-dated catalyst, with near-term stock moves more tied to broader pipeline updates and sector risk appetite.

The study is currently in the early, setup phase and remains active on the ClinicalTrials portal, where further details and future updates will be available.

To learn more about CCCC’s potential, visit the C4 Therapeutics, Inc. drug pipeline page.