Day One Biopharmaceuticals to acquire Mersana Therapeutics for up to $285M

Day One Biopharmaceuticals (DAWN) announced it has signed a definitive merger agreement for Day One to acquire Mersana Therapeutics (MRSN). Under the terms of the definitive merger agreement, Day One will promptly commence a tender offer to acquire all of the outstanding shares of Mersana common stock at a price of $25 per share in cash at closing plus one non-tradable CVR per share to receive certain potential milestone payments of up to an aggregate of $30.25 per CVR in cash, for total consideration of up to $55.25 per share in cash, representing a total equity value of approximately $129M at closing and representing a total deal value of up to approximately $285M. Day One expects to finance the acquisition with existing cash resources. Day One’s strong cash position and financial profile is expected to enable development of Emi-Le through potential approval with no additional financing required. The transaction is expected to close by the end of January 2026, subject to receipt of applicable regulatory approvals and the satisfaction of other customary conditions.