Every Form 4 that Mersana Therapeutics, Inc. (MRSN) has filed with the SEC in the last 12 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A Form 4 covers the transactions officers, directors and large holders report, so if you follow MRSN and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full MRSN filings page.
Mersana Therapeutics, Inc. director Andrew Hack reported changes in his holdings tied to the company’s acquisition by Day One Biopharmaceuticals. Under the merger agreement, each share of Mersana common stock tendered before the offer deadline was exchanged for $25.00 in cash per share plus one contingent value right, which may pay up to an additional $30.25 in cash per CVR if specified milestones are met. As of January 6, 2026, when the merger became effective and Mersana became a wholly owned subsidiary of Day One, Hack’s direct holding of 578 common shares and indirect interest in 346,545 shares held by Bain Capital Life Sciences entities were reported as affected by this exchange. Multiple stock options to buy Mersana common stock were also reported as disposed of with zero options remaining following the merger-related treatment of in-the-money and out-of-the-money awards.
Mersana Therapeutics director Allene Diaz reported the disposition of her remaining equity in connection with the acquisition of Mersana by Day One Biopharmaceuticals. Common shares of Mersana were exchanged for $25.00 per share in cash plus one non-tradeable contingent value right (CVR) per share. Each CVR entitles holders to potential milestone payments of up to an aggregate $30.25 per CVR, subject to specified milestones.
Under the merger agreement, vested stock options with exercise prices below $25.00 per share were cancelled and converted into the right to receive the cash-and-CVR offer value minus the option exercise price, while options with exercise prices at or above $25.00 per share became fully vested for a limited period and were cancelled at closing if not exercised, with no consideration paid. Following these transactions, Diaz reported 0 shares and 0 stock options beneficially owned.
Mersana Therapeutics director Willard H. Dere reported changes in his holdings following the completion of a merger in which Mersana became a wholly owned subsidiary of Day One Biopharmaceuticals. Each share of Mersana common stock tendered in the offer was exchanged for $25.00 in cash per share plus one contingent value right (CVR) per share, with the CVR providing for potential milestone payments of up to $30.25 per CVR in cash. In connection with the merger’s effective time on January 6, 2026, Dere’s 1,567 shares of common stock and multiple stock options were either cashed out or cancelled in accordance with the merger agreement mechanics, leaving him with no reported remaining Mersana equity.
Mersana Therapeutics insider Alejandra Carvajal, SVP and Chief Legal Officer, reported automatic changes to her equity holdings following the company’s acquisition by Day One Biopharmaceuticals. Common shares tendered in the offer were exchanged for $25.00 per share in cash plus one contingent value right, which can pay up to an additional $30.25 per share if specified milestones are met. After the tender offer, Emerald Merger Sub merged into Mersana, making Mersana a wholly owned subsidiary of Day One.
Under the merger agreement, vested in-the-money stock options were cancelled in return for the cash-and-CVR offer price minus the option exercise price. Out-of-the-money options became fully vested shortly before closing but expired without payment if not exercised by the last exercise date. All outstanding restricted stock units were cancelled and converted into the right to receive the same offer price as common shares.
Mersana Therapeutics, Inc. filed a Form 4 for SVP, Chief Development Bala Mohan tied to the closing of its merger with Day One Biopharmaceuticals, Inc. On completion of a tender offer under a Merger Agreement, Mersana common shares tendered were exchanged for $25.00 per share in cash, plus one contingent value right (CVR) per share, with each CVR eligible for up to an additional $30.25 in cash upon specified milestones. After the tender offer, Emerald Merger Sub, Inc. merged with Mersana, which became a wholly owned subsidiary of Day One as of January 6, 2026.
Consistent with the Merger Agreement, Mohan’s outstanding in-the-money stock options became fully vested, were cancelled, and converted into cash rights equal to the offer price minus the option exercise price per share. Out-of-the-money options became fully vested but, if not exercised by the stated last exercise date, were cancelled at the effective time with no payment. Outstanding restricted stock units were cancelled and converted into the right to receive the same cash-and-CVR offer price per underlying share.
Mersana Therapeutics, Inc. was acquired by Day One Biopharmaceuticals, with shares of common stock tendered for $25.00 per share in cash plus one non-tradeable contingent value right (CVR) per share. Each CVR provides the right to receive up to an additional $30.25 in cash per CVR if specified milestones are met. The merger closed with the buyer’s subsidiary merging into Mersana on January 6, 2026, making Mersana a wholly owned subsidiary.
In connection with the merger, VP and Chief Accounting Officer Ashish Mandelia reported that 2,300 shares of common stock and all reported stock options and restricted stock units were either converted into the cash-and-CVR consideration or cancelled under the merger terms, leaving zero securities beneficially owned after the transactions.
Mersana Therapeutics, Inc. completed its sale to Day One Biopharmaceuticals, Inc., with all tendered common shares exchanged for $25.00 in cash per share plus one contingent value right (CVR) per share. Each CVR represents potential milestone payments of up to an additional $30.25 in cash per CVR, subject to specified milestones and conditions. After the tender offer, Emerald Merger Sub, Inc. merged into Mersana on January 6, 2026, making Mersana a wholly owned subsidiary of Day One.
Options with exercise prices below the $25.00 upfront cash amount became fully vested and were cancelled in exchange for the Offer Price minus the option exercise price. Options with exercise prices at or above $25.00 were fully vested and exercisable for a limited period before the merger, and any such options not exercised by the last exercise date were cancelled at closing with no payment. Director Anna Protopapas reported exchanges of common shares, including shares held through family trusts for the benefit of her spouse and children, and the cancellation of multiple stock option awards in connection with these merger terms.
Mersana Therapeutics (MRSN) insider activity: The SVP, Chief Development Officer reported RSU vesting of 250 shares of common stock on October 25, 2025, and an automatic sell-to-cover of 77 shares at $9.90 on October 27, 2025 under a Rule 10b5-1 trading plan adopted on May 10, 2023. Following these transactions, direct beneficial ownership is 2,922 shares.
The amounts reflect the one-for-twenty-five reverse stock split effected on July 25, 2025. Each RSU represented one common share, and the RSUs were fully vested as of October 25, 2025.