On January 6, 2026 Day One Biopharmaceuticals, Inc. (Nasdaq: DAWN) ("Day One"), a biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, reported the successful close of its acquisition of Mersana Therapeutics, Inc., (NASDAQ: MRSN) ("Mersana") following completion of all conditions of the tender offer to acquire all outstanding shares of Mersana at a price of $25 per share in cash, plus one non-tradable contingent value right ("CVR") per share to receive certain potential milestone payments of up to an aggregate of $30.25 per CVR in cash.
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"This acquisition of Mersana is a strategic fit with Day One’s mission and ambitions, allowing us to continue to expand into adult oncology while maintaining a focus on rare cancers. With promising early clinical data, Emi-Le represents a potentially transformative advancement in the treatment of ACC, and we will leverage our distinct capabilities to rapidly develop the asset and pursue registration to reach patient communities who have no approved therapies today," said Jeremy Bender, Ph.D., chief executive officer of Day One. "Building on the strong momentum of OJEMDA in the market and our continually progressing pipeline, this acquisition strengthens our overall position to expand our impact on patient communities while delivering sustainable business growth."
Through this acquisition, Day One has added a second novel ADC to the company’s clinical pipeline. Emi-Le (emiltatug ledadotin) represents an innovative and differentiated ADC directed against B7-H4, a well-characterized target in certain cancers including adenoid cystic carcinoma (ACC), a challenging rare cancer usually arising within the salivary gland with a clear unmet medical need. For additional background on Emi-Le and the acquisition, please read the announcement press release and view Day One’s investor presentation.
Terms of the Acquisition
Day One has acquired all outstanding shares of Mersana common stock at a price of $25 per share in cash, 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. The CVR is payable subject to certain terms and conditions of achievement of specified milestones.
The tender offer expired as scheduled at one minute following 11:59 p.m., Eastern Time, on January 5, 2026 (the "Expiration Date"). The depositary for the tender offer, Computershare Trust Company, N.A., advised Day One that, as of the Expiration Date, a total of 3,029,135 shares of Mersana common stock were validly tendered and not validly withdrawn pursuant to the tender offer, representing 60.57% of the outstanding shares of Mersana common stock and satisfying the minimum condition to consummate the tender offer. All of the conditions of the tender offer having been satisfied, Day One accepted for payment all such tendered shares, and following a statutory merger under Section 251(h) of the Delaware General Corporation Law on January 6, 2026, Mersana became a direct wholly owned subsidiary of Day One. All remaining shares of Mersana common stock that were not tendered in the tender offer were converted into the right to receive the same per share consideration as shares that were tendered in the tender offer, as described above. With the completion of the acquisition, Mersana’s common stock will cease to trade on the Nasdaq stock exchange prior to market open on January 6, 2026 and Mersana’s common stock will be delisted from Nasdaq.
Advisors
Gordon Dyal & Co., LLC acted as the exclusive financial advisor to Day One, with Fenwick & West LLP serving as legal counsel. TD Cowen acted as financial advisor to Mersana, with Wilmer Cutler Pickering Hale and Dorr LLP serving as legal counsel.
(Press release, Day One, JAN 6, 2026, View Source [SID1234661751])