Form 4: Mersana Director's Holdings Update Post-Merger

Mersana Therapeutics director Lawrence M. Alleva reports changes in beneficial ownership following the company's merger with Day One Biopharmaceuticals, including cash-out of shares and options.

Summary

• Mersana Therapeutics, Inc. has completed its merger with Emerald Merger Sub, Inc., a wholly-owned subsidiary of Day One Biopharmaceuticals, Inc., effective January 6, 2026.
• As a result of the merger, Mersana's common stock was exchanged for an Offer Price consisting of $25.00 per share in upfront cash and one non-tradeable contingent value right (CVR) per share.
• Each CVR represents the right to receive contingent milestone payments of up to an aggregate of $30.25 per CVR in cash upon the achievement of specified milestones.
• Lawrence M. Alleva, a director, reported the disposition of 578 shares of common stock held directly and 84 shares held indirectly by the Lawrence M. Alleva Revocable Trust, both for 0 D (disposed) following the transaction.
• Stock options with an exercise price less than the $25.00 Upfront Cash Consideration (Cash-Out Options) became fully vested, cancelled, and converted into the right to receive the Offer Price minus the exercise price.
• Stock options with an exercise price equal to or greater than the $25.00 Upfront Cash Consideration (OTM Options) became fully vested and exercisable until the fifth business day following the Acceleration Date (10 business days prior to closing), after which unexercised OTM Options were cancelled without consideration.
• Alleva reported the disposition of numerous stock options with various exercise prices ranging from $9.0775 to $572.5, all resulting in 0 derivative securities beneficially owned following the reported transaction.

Sentiment

Score: 7

Explanation: The sentiment is positive as the merger successfully completed, providing shareholders with immediate cash and potential future upside through CVRs. While some out-of-the-money options were cancelled, the overall transaction represents a planned and executed strategic event.

Positives

• The merger of Mersana Therapeutics, Inc. with Day One Biopharmaceuticals, Inc. has been successfully completed, providing liquidity to shareholders.
• Shareholders received an Upfront Cash Consideration of $25.00 per share, providing immediate value.
• Shareholders also received Contingent Value Rights (CVRs) which offer potential additional payments of up to $30.25 per CVR upon the achievement of specified milestones, providing upside potential.

Negatives

• Stock options with an exercise price equal to or greater than the Upfront Cash Consideration ($25.00) that were not exercised by the Last Exercise Date were cancelled without any consideration, resulting in a loss of potential value for those option holders.

Risks

• The contingent value rights (CVRs) are non-tradeable and their value is dependent on the achievement of certain specified milestones, meaning the full $30.25 per CVR is not guaranteed.

Future Outlook

Mersana Therapeutics, Inc. is now a wholly-owned subsidiary of Day One Biopharmaceuticals, Inc. The future financial performance for former Mersana shareholders is tied to the achievement of milestones associated with the contingent value rights (CVRs), which could yield up to an additional $30.25 per CVR.

Industry Context

This transaction reflects ongoing consolidation and strategic realignments within the biotechnology and pharmaceutical sectors, where larger companies acquire smaller, innovative firms to expand pipelines or gain access to specific technologies. The use of contingent value rights (CVRs) is a common mechanism in biotech mergers to bridge valuation gaps and share future development risks and rewards.

Stakeholder Impact

• Shareholders of Mersana Therapeutics, Inc. received $25.00 per share in cash and one contingent value right (CVR) per share, providing liquidity and potential future value.
• Holders of in-the-money stock options received cash consideration based on the Offer Price minus their exercise price.
• Holders of out-of-the-money stock options that were not exercised by the specified deadline had their options cancelled without consideration.

Next Steps

• Monitoring the achievement of specified milestones for the contingent value rights (CVRs) to determine if additional payments will be made to former Mersana shareholders.

Key Dates

Keywords

Mersana Therapeutics, Day One Biopharmaceuticals, Merger, Acquisition, Form 4, Beneficial Ownership, Stock Options, Contingent Value Rights, MRSN, Insider Transaction