SCHEDULE 13G/A

C4 Therapeutics Inc

Common Stock, par value $0.0001 per share · CUSIP: 12529R107

Event date: 2025-12-31

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• OrbiMed Advisors LLC

  Shares: 521,368.00 · Class: 0.5%

• OrbiMed Capital LLC

  Shares: 883,534.00 · Class: 1.0%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.