Welcome to our dedicated page for Mersana Therapeutics SEC filings (Ticker: MRSN), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
The Mersana Therapeutics, Inc. (MRSN) SEC filings page on Stock Titan provides access to the company’s regulatory disclosures as filed with the U.S. Securities and Exchange Commission. Mersana, a clinical-stage biopharmaceutical company focused on antibody-drug conjugates (ADCs), uses current reports on Form 8-K and other SEC filings to communicate material events, financial results, capital structure changes and transaction agreements.
Recent Form 8-K filings include disclosures about quarterly financial results and business updates, which are furnished under Item 2.02 and accompanied by press release exhibits. Other 8-Ks describe corporate actions such as the 1-for-25 reverse stock split of Mersana’s common stock, implemented via a Certificate of Amendment to its certificate of incorporation, and the resulting trading of MRSN on a post-split basis. The company has also filed an 8-K detailing a Nasdaq notice regarding non-compliance with the Market Value of Listed Securities requirement, explaining the compliance period and potential consequences if the deficiency is not cured.
A key 8-K filing outlines Mersana’s entry into an Agreement and Plan of Merger with Day One Biopharmaceuticals, Inc. and a wholly owned subsidiary. This document summarizes the planned tender offer for all outstanding Mersana shares, the structure of the cash consideration and contingent value rights, the subsequent merger mechanics and the conditions required to close the transaction. Additional 8-K disclosure describes the repayment and termination of a prior loan and security agreement, documenting the payoff amount and the discharge of related obligations.
On Stock Titan, these filings are supplemented by AI-powered summaries that highlight the main points of each document, helping users quickly understand items such as reverse stock split details, listing notices, merger terms and financing changes. Investors can review Forms 8-K alongside other periodic reports like 10-K and 10-Q (when available through EDGAR) to follow Mersana’s financial reporting, capital structure developments and the regulatory steps associated with its proposed acquisition by Day One. Real-time updates ensure new filings, including any future Form 4 insider transaction reports or proxy materials related to corporate actions, are captured as they are posted to the SEC’s system.
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, Inc. is having its common stock removed from listing and/or registration on the Nasdaq Stock Market LLC, as reflected in a Form 25 filing under Section 12(b) of the Securities Exchange Act of 1934. Nasdaq certifies that it has reasonable grounds to believe it meets all requirements for filing this notification and that it has complied with its own rules for striking the class of securities from listing and withdrawing registration.
Mersana Therapeutics, Inc. reports that it has been acquired by Day One Biopharmaceuticals, Inc. through a completed tender offer and follow-on merger. Stockholders who tendered their shares receive $25.00 in cash per share, plus one contingent value right (CVR) per share, which can pay up to an additional $30.25 per share in cash if specified milestones are achieved. The tender offer, which expired on January 5, 2026, resulted in 3,029,135 shares being validly tendered, representing about 60.57% of outstanding shares, satisfying the minimum condition. Following a short-form merger under Delaware law on January 6, 2026, Mersana became a wholly owned subsidiary of Day One, its common stock trading on Nasdaq was suspended, and the company is being delisted and deregistered as a public company. Mersana also terminated its at-the-market sales agreement and all stock incentive and employee stock purchase plans, and its prior board and officers were replaced by designees from the acquirer.
Mersana Therapeutics is being acquired by Day One Biopharmaceuticals after completing a tender offer and follow-on merger. Day One’s subsidiary accepted 3,029,135 Mersana shares that were validly tendered, representing approximately 60.57% of the shares outstanding at the offer’s expiration. Holders who tendered will receive $25.00 per share in cash, plus one contingent value right per share, which can pay up to an additional $30.25 in cash upon achieving specified milestones. On January 6, 2026, Day One completed a merger under Delaware law, making Mersana a wholly owned subsidiary. Each remaining share (with limited exceptions for treasury, affiliate, and appraisal shares) was converted into the right to receive the same offer price in cash, and the shares will be delisted from Nasdaq with plans to terminate SEC registration and reporting.
Day One Biopharmaceuticals, through wholly owned subsidiary Emerald Merger Sub, announced plans to commence a tender offer to acquire all outstanding shares of Mersana Therapeutics, pursuant to an Agreement and Plan of Merger dated November 12, 2025.
The communication is a Schedule TO-C and is limited to preliminary disclosures; the tender offer has not yet commenced. On the commencement date, Day One and the Purchaser will file a Schedule TO (including the Offer to Purchase and Letter of Transmittal), and Mersana will file a Schedule 14D-9. Closing of the transaction is subject to conditions described in the merger agreement, which include sufficient shares being tendered and required regulatory clearances.
The filing also lists Exhibit 99.1, a transcript from a Day One investor call held on November 13, 2025, and directs investors to the SEC’s website and Day One’s IR site for future tender offer materials.
Mersana Therapeutics (MRSN) filed its Q3 2025 10‑Q, reporting collaboration revenue of $11.0 million and a net loss of $7.5 million (basic and diluted EPS $(1.51)) for the quarter. Cash and cash equivalents were $56.4 million as of September 30, 2025. For the nine months, operating cash use totaled $55.1 million, reflecting continued investment in R&D and reduced G&A.
The company recorded Q3 collaboration revenue contributions from its partnerships, including $8.6 million under the GSK agreement, $0.6 million from the 2024 Johnson & Johnson clinical supply agreement, and $1.8 million from Merck KGaA. Deferred revenue totaled $102.7 million at period end.
Mersana repaid its credit facility on July 1, 2025 with a payment of approximately $17.9 million, eliminating its debt. It completed a 1‑for‑25 reverse stock split on July 25, 2025 and finished a restructuring that reduced headcount by about 55%, incurring $4.1 million in restructuring costs year‑to‑date. The filing states substantial doubt about the company’s ability to continue as a going concern. On November 12, 2025, the company entered into a merger agreement with Day One Biopharmaceuticals via tender offer and subsequent merger. Shares outstanding were 4,998,750 as of November 7, 2025.
Mersana Therapeutics, Inc. filed a current report stating that it issued a press release with business updates and financial results for the fiscal quarter ended September 30, 2025. The company’s common stock trades on The Nasdaq Stock Market under the symbol MRSN. The press release is included as Exhibit 99.1, while Exhibit 104 covers the interactive data for the cover page. The company notes that the information in this earnings-related item and the attached exhibit is being furnished, not filed, which limits its exposure to certain Exchange Act liabilities and controls how it may be incorporated by reference into other SEC documents.
Day One Biopharmaceuticals plans a tender offer for all outstanding shares of Mersana Therapeutics via Emerald Merger Sub, its wholly owned subsidiary, as outlined in a Schedule TO-C. The communication relates solely to preliminary communications made before the commencement of the tender offer and is pursuant to an Agreement and Plan of Merger dated November 12, 2025.
The offer has not yet commenced. Upon commencement, Day One and the Purchaser will file a Schedule TO with an Offer to Purchase and Letter of Transmittal, and Mersana will file a Schedule 14D-9. The filing highlights forward-looking risks, including satisfaction of closing conditions, sufficient tenders, required regulatory approvals, potential competing offers, integration challenges, and the possibility that contingent value right milestones may not be achieved.