C4 Therapeutics, Inc.

This Current Report on Form 8-K contains “forward-looking statements” of C4 Therapeutics, Inc. within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including without limitation, express or implied statements regarding: the clinical significance of the biomarker data presented from the Company’s Phase 1 clinical trial of cemsidomide in combination with dexamethasone in patients with RRMM and the Phase 1b trial of cemsidomide in combination with elranatamab; the ability of cemsidomide to drive coordinated activation of T cells and functional reprogramming of NK cells; the potential of enhanced immune cell function observed at the highest dose levels studied to translate into clinical benefit; the ability of cemsidomide to drive the expansion and activation of CD8+ effector memory T cells and prevent T-cell exhaustion; the translational and mechanistic support for cemsidomide as a potential combination partner for immune-based therapies; the advancement of the Phase 1b trial into a dose escalation safety cohort at the 100 µg cemsidomide dose level and an expansion cohort at the 75 µg cemsidomide dose level; and the anticipated timing of data from all cohorts evaluated in the Phase 1b trial in mid-2027. Any forward-looking statements in this Current Report on Form 8-K are based on management’s current expectations and beliefs of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to: uncertainties related to the initiation, timing, advancement and conduct of preclinical and clinical studies and other development requirements for the Company’s product candidates; the risk that preclinical or clinical data, including biomarker data or signs of biologic activity, may not be predictive of long-term results or translate across programs or the patient population; the risk that any one or more of the Company’s product candidates will cost more to develop or may not be successfully developed and commercialized; and the risk that sufficient capital to fund the Company’s future operations will be available to the Company on acceptable terms or at the times required. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause the Company’s actual results to differ from those contained in the forward-looking statements, see the section entitled “Risk Factors” in C4 Therapeutics’ most recent annual report on Form 10-K and/or Quarterly Report on Form 10-Q, as filed with the Securities and Exchange Commission. Except as otherwise stated, the information in this Current Report on Form 8-K is as of the date of this Current Report on Form 8-K, and the Company undertakes no duty to update this information unless required by law.

Item 9.01 Financial Statements and Exhibits.

(d)Exhibits. The exhibits shall be deemed to be filed or furnished, depending on the relevant item requiring such exhibit, in accordance with the provisions of Item 601 of Regulation S-K (17 CFR 229.601) and Instruction B.2 to this form.