SCHEDULE: Mersana Therapeutics Acquired; Bain Capital Exits Stake

Bain Capital Life Sciences reports 0% ownership in Mersana Therapeutics following its acquisition by Day One Biopharmaceuticals for $25.00 cash plus CVR per share.

Summary

• Mersana Therapeutics, Inc. has been acquired by Day One Biopharmaceuticals, Inc. through its subsidiary, Emerald Merger Sub, Inc. (Purchaser).
• The acquisition was completed on January 6, 2026, following a tender offer.
• Purchaser irrevocably accepted for payment all validly tendered shares of Mersana's Common Stock.
• Mersana Therapeutics is now a direct wholly-owned subsidiary of Day One Biopharmaceuticals, Inc.
• Bain Capital Life Sciences Fund II, L.P., BCIP Life Sciences Associates, LP, and BCLS II Investco, LP (the "Reporting Persons") no longer hold any shares of Mersana Therapeutics Common Stock.
• All shares held by the Reporting Persons were cancelled and converted into the right to receive the Offer Price.
• Dr. Hack resigned as a director of Mersana Therapeutics effective as of the merger's completion.

Sentiment

Score: 7

Explanation: The sentiment is generally positive as it confirms the successful completion of a planned acquisition, providing a defined exit for shareholders and the reporting entities. While it marks the end of Mersana as an independent public company, the transaction itself was a positive event for the selling shareholders.

Positives

• The successful completion of the merger provides liquidity and a defined return for Mersana Therapeutics shareholders.
• Bain Capital Life Sciences entities have successfully exited their investment in Mersana Therapeutics.

Negatives

• Mersana Therapeutics common stock is no longer publicly traded, removing investment opportunities in the independent entity.
• Shareholders no longer have an equity stake in Mersana Therapeutics' future growth as an independent company.

Risks

• The contingent value right (CVR) component of the offer price is non-tradeable and its value is dependent on the achievement of certain future milestones, introducing uncertainty regarding the full potential payout of up to $30.25 per share.

Future Outlook

Mersana Therapeutics, Inc. is now a direct wholly-owned subsidiary of Day One Biopharmaceuticals, Inc. and its common stock is no longer publicly traded. The future outlook for the former public entity is now integrated into Day One Biopharmaceuticals' strategic plans.

Industry Context

This acquisition reflects ongoing consolidation within the biotechnology sector, where larger pharmaceutical or biotech companies acquire smaller, innovative firms to expand their pipelines or gain access to specific technologies. Such transactions are common strategies for growth and portfolio diversification.

Comparison to Industry Standards

• This filing reports the completion of a specific acquisition and does not contain operational or financial results that can be directly compared to industry benchmarks or specific comparable companies' performance metrics. The transaction terms (cash plus CVR) are a common structure in biotech acquisitions, balancing immediate value with future upside potential tied to clinical or regulatory milestones.

Management Changes

Corporate Governance

Stakeholder Impact

• Shareholders: Received $25.00 per share in cash plus one non-tradeable contingent value right (CVR) per share, representing the right to receive certain contingent milestone payments of up to an aggregate of $30.25 per share.
• Employees: Mersana Therapeutics employees are now part of Day One Biopharmaceuticals, Inc.
• Bain Capital Life Sciences: Successfully exited their investment in Mersana Therapeutics.

Key Dates

Keywords

Mersana Therapeutics, Day One Biopharmaceuticals, Bain Capital, Merger, Acquisition, Tender Offer, Schedule 13D, CVR, Biotechnology