Officer Sale of Shares for Tax Withholding

Brandi Roberts, Chief Financial Officer of Definium Therapeutics, Inc., sold 3,013 common shares on June 25, 2026, at a price of $45.03 per share. This sale was conducted to cover tax withholding obligations related to the settlement of vested restricted stock units, as per sell-to-cover elections under a Rule 10b5-1 plan adopted on May 30, 2025. Following this transaction, Ms. Roberts holds 209,487 shares. The transaction code was "S" for sale, and the shares were disposed of ("D").