Overview
- Mersana shareholders will receive $25.00 per share in cash upfront, valuing the equity at about $129 million.
- Contingent value rights could add up to $30.25 per share, including $4 at the start of a pivotal ACC-1 trial, $9 upon FDA approval, and the remainder tied to further clearances and $300 million in annual sales by 2037.
- Day One plans to prioritize emiltatug ledadotin, a B7-H4–targeting antibody-drug conjugate, for adenoid cystic carcinoma type 1 after prior focus on triple-negative breast cancer.
- Mersana’s board unanimously approved the transaction, which is expected to close by the end of January 2026.
- Mersana shares jumped more than 200% on the announcement as Day One shares fell modestly, and Day One reported $451.6 million in cash alongside growing Ojemda revenue to support development.