SCHEDULE 13G/A

Definium Therapeutics Inc

Common Shares, no par value per share · CUSIP: 24477V105

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

• Commodore Capital LP

  Shares: 7,428,775.00 · Class: 7.2%

• Commodore Capital Master LP

  Shares: 7,428,775.00 · Class: 7.2%

• Robert Egen Atkinson

  Shares: 7,428,775.00 · Class: 7.2%

• Michael Kramarz

  Shares: 7,428,775.00 · Class: 7.2%

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