Mersana Therapeutics Stock News
Day One Biopharmaceuticals to Acquire Mersana Therapeutics
Day One to Acquire Mersana Therapeutics to Advance Mission to Bring New Medicines to People of All Ages With Life-Threatening Diseases
Mersana Therapeutics Inc Proposed Deal for $25.00 per Share in Cash
Acquisition expands Day One’s portfolio with novel antibody-drug conjugate （ADC） emiltatug ledadotin （Emi-Le）
Emi-Le has demonstrated early anti-tumor activity in an ongoing Phase 1 study for adenoid cystic carcinoma type-1 （ACC-1）， a cancer with high unmet need and a lack of therapeutic options
Day One will apply existing scientific and commercial capabilities to this investigational innovative therapeutic with a clear potential registration path
BRISBANE, Calif., Nov. 13, 2025 （GLOBE NEWSWIRE） — Day One Biopharmaceuticals, Inc. （Nasdaq: DAWN） （”Day One” or the “Company”）， a biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, today announced it has signed a definitive merger agreement for Day One to acquire Mersana Therapeutics （”Mersana”）。
The transaction positions the Company for continued success and expansion of its oncology portfolio, adding Emi-Le, a potential first-in-class monotherapy for patients with ACC, an aggressive cancer with a well-defined patient population and high unmet need, most often arising from the salivary gland. The early anti-tumor activity observed with Emi-Le in an ongoing Phase 1 study, in a disease with a clear unmet medical need, may support a fast path to registration. Emi-Le represents an innovative and differentiated ADC directed against B7-H4, a well-characterized target in certain cancers. B7-H4 is highly expressed in ACC as well as in other adult and pediatric cancers. As a novel targeted investigational agent with monotherapy anti-tumor activity intended for a well-defined patient population without any approved therapies or a clear standard of care, the Company believes that Emi-Le is well positioned for potential rapid development and commercialization.
“This acquisition will add a potential game-changing new medicine to the Day One portfolio and, if approved, will broaden our opportunities for patient impact and for continued growth and value creation,” said Jeremy Bender, Ph.D., chief executive officer of Day One. “The addition of the Emi-Le program to our portfolio allows us to leverage the research and development expertise, and the commercial capabilities, that already exist within Day One to address underserved, rare and life-threatening cancers in patients of all ages.”
Terms of the Agreement
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 $129 million at closing and representing a total deal value of up to approximately $285 million. The CVR is payable subject to certain terms and conditions of achievement of the following milestones:
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.
About Day One Biopharmaceuticals
Day One Biopharmaceuticals is a commercial-stage biopharmaceutical company that believes when it comes to pediatric cancer, we can do better. The Company was founded to address a critical unmet need: the dire lack of therapeutic development in pediatric cancer. Inspired by “The Day One Talk” that physicians have with patients and their families about an initial cancer diagnosis and treatment plan, Day One aims to re-envision cancer drug development and redefine what’s possible for all people living with cancer–regardless of age–starting from Day One.
Day One partners with leading clinical oncologists, families, and scientists to identify, acquire, and develop important targeted cancer treatments. The Company’s pipeline includes tovorafenib （OJEMDA（TM）） and DAY301.
Day One is based in Brisbane, California. For more information, please visit or find the Company on LinkedIn or X.
Mersana Therapeutics Stock Rating
1、Mersana Therapeutics Shares Are Trading Higher After the Company Announced It Will Be Acquired by Day One Biopharmaceuticals.
2、Mersana Therapeutics MRSN stock underwent a massive rally on an acquisition deal.
November 14, 2025,William Blair Downgrades Mersana Therapeutics（MRSN.US） to Hold Rating
LifeSci Capital Downgrades Mersana Therapeutics（MRSN.US） to Hold Rating
Truist Financial Downgrades Mersana Therapeutics（MRSN.US） to Hold Rating, Cuts Target Price to $30.75
Truist Downgrades Mersana Therapeutics to Hold From Buy, Adjusts PT to $30.75 From $36
1、Mersana Therapeutics （MRSN） has an average rating of overweight and mean price target of $32.54, according to analysts polled by FactSet.
2、Mersana Therapeutics Inc : Btig Cuts to Neutral From Buy
Mersana Therapeutics, Inc. （MRSN） Description
Mersana Therapeutics, Inc., a clinical-stage biopharmaceutical company, develops antibody-drug conjugates （ADC） for cancer patients with unmet needs. The company develops Emi-Le （XMT-1660）， a B7-H4-targeting Dolasynthen ADC candidate, which is in Phase 1 clinical trial; and XMT-2056, an Immunosynthen ADC targeting a novel human epidermal growth factor receptor 2 that is in Phase 1 clinical trial. Its preclini