Mersana Therapeutics, Inc. 8-K

What Happened
Mersana Therapeutics, Inc. filed an 8-K reporting that the previously announced merger (effective January 6, 2026) closed, making Mersana a direct wholly‑owned subsidiary of the purchaser (Parent/Day One). At the Effective Time the company amended and restated its certificate of incorporation and bylaws, senior management and the board changed to representatives from Purchaser, and the company has initiated steps to suspend Nasdaq trading and deregister the Common Stock.

Key Details

• Merger closed effective January 6, 2026; Upfront Cash Consideration was funded from Parent’s cash on hand.
• Nasdaq: on January 5, 2026 Mersana requested Nasdaq suspend trading of its common stock effective 8:00 p.m. ET Jan 5, 2026 and intends to file Form 25 (delisting) and Form 15 (termination of registration and suspension of reporting obligations).
• Governance & leadership: eight incumbent directors (Lawrence Alleva, William Dere, Allene Diaz, Andrew Hack, Kristen Hege, Martin Huber, David Mott, Anna Protopapas) resigned at the Effective Time; Charles N. York II and Adam Dubow (Purchaser directors/officers) became directors and officers of Mersana (York named CEO, President, CFO, COO and Treasurer; Dubow named Chief Compliance Officer, General Counsel and Secretary). Incumbent officers ceased being officers immediately after the Merger.
• Equity plans and financing: the at‑the‑market Sales Agreement with Cowen was terminated effective January 6, 2026; the 2007, 2017 and 2022 Stock Incentive Plans were terminated effective at the Effective Time, and the 2017 Employee Stock Purchase Plan was terminated immediately prior to the Effective Time. A Contingent Value Rights Agreement dated January 6, 2026 was filed as an exhibit.

Why It Matters
For investors, the merger and related actions materially change Mersana’s public status and governance. The company is being taken private as a direct wholly‑owned subsidiary, trading on Nasdaq will be suspended and the company will seek deregistration and suspension of periodic reporting — meaning public liquidity and SEC reporting will cease once filings are accepted. Leadership and board turnover is immediate and complete, signaling control now rests with the purchaser’s nominees. Termination of the Sales Agreement and equity plans means the company will no longer sell shares through the prior ATM program or grant further awards under those plans. The Contingent Value Rights agreement may affect potential future payments to former stockholders as described in the merger documents.