| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| MOTT DAVID M | Director | C/O MERSANA THERAPEUTICS, INC., 840 MEMORIAL DRIVE, CAMBRIDGE | /s/ David Mott | 06 Jan 2026 | 0001219871 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | MRSN | Common Stock | Disposition pursuant to a tender of shares in a change of control transaction | -23,546 | -100% | 0 | 06 Jan 2026 | Direct | F1, F2 | ||
| transaction | MRSN | Common Stock | Disposition pursuant to a tender of shares in a change of control transaction | -383 | -100% | 0 | 06 Jan 2026 | See Footnote | F1, F2, F5 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Underlying Class | Amount | Exercise Price | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -2,460 | -100% | 0 | 06 Jan 2026 | Common Stock | 2,460 | $9.08 | Direct | F3 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -264 | -100% | 0 | 06 Jan 2026 | Common Stock | 264 | $434.75 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -400 | -100% | 0 | 06 Jan 2026 | Common Stock | 400 | $306.75 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -1,011 | -100% | 0 | 06 Jan 2026 | Common Stock | 1,011 | $107.75 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -1,000 | -100% | 0 | 06 Jan 2026 | Common Stock | 1,000 | $107.75 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -788 | -100% | 0 | 06 Jan 2026 | Common Stock | 788 | $134.00 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -368 | -100% | 0 | 06 Jan 2026 | Common Stock | 368 | $572.50 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -181 | -100% | 0 | 06 Jan 2026 | Common Stock | 181 | $527.25 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -1,002 | -100% | 0 | 06 Jan 2026 | Common Stock | 1,002 | $372.50 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -740 | -100% | 0 | 06 Jan 2026 | Common Stock | 740 | $161.00 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -1,800 | -100% | 0 | 06 Jan 2026 | Common Stock | 1,800 | $90.50 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -734 | -100% | 0 | 06 Jan 2026 | Common Stock | 734 | $216.00 | Direct | F4 | ||
| transaction | MRSN | Stock Option (right to buy) | Disposed to Issuer | -2,200 | -100% | 0 | 06 Jan 2026 | Common Stock | 2,200 | $56.50 | Direct | F4 |
DAVID M. MOTT is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may continue.
| Id | Content |
|---|---|
| F1 | Pursuant to the terms of that certain Agreement and Plan of Merger (the "Merger Agreement"), by and among the Issuer, Day One Biopharmaceuticals, Inc. ("Parent") and Parent's direct wholly-owned subsidiary, Emerald Merger Sub, Inc. ("Purchaser"), dated as of November 12, 2025, the shares (the "Shares") of common stock, par value $0.0001 per share, of the Issuer (the "Common Stock") that were tendered to Purchaser prior to the expiration time of the Offer were exchanged for: (i) $25.00 per Share, net to the stockholder in cash, without interest and less any applicable tax withholding (the "Upfront Cash Consideration"), plus (ii) one non-tradeable contingent value right per Share (each, a "CVR"), |
| F2 | (continued from footnote 1) which represents the right to receive certain contingent milestone payments of up to an aggregate of $30.25 per CVR in cash, without interest and less any applicable tax withholding, upon the achievement of certain specified milestones in accordance with the terms and subject to the conditions of a contingent value rights agreement entered into by Parent and the rights agent (the Upfront Cash Consideration plus one CVR, collectively, the "Offer Price"). After completion of the tender offer, pursuant to the terms of the Merger Agreement, Purchaser merged with and into the Issuer, effective as of January 6, 2026 (the "Effective Time"), with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Parent. |
| F3 | Pursuant to the terms of the Merger Agreement, effective as of immediately prior to the Effective Time, each option to purchase shares of Common Stock ("Issuer Option") that was outstanding and unexercised as of immediately prior to the Effective Time and had an exercise price per Share that was less than the Upfront Cash Consideration (each, a "Cash-Out Option"), became fully vested and was automatically cancelled and converted into the right to receive, without interest and subject to deduction for any required tax withholding, (i) the Offer Price minus (ii) the exercise price payable per share of Common Stock underlying such Cash-Out Option. |
| F4 | Pursuant to the terms of the Merger Agreement, effective as of 10 business days prior to the closing of the Merger (the "Acceleration Date"), each Issuer Option then outstanding and unexercised that had an exercise price per Share that was equal to or greater than the Upfront Cash Consideration (each, an "OTM Option"), became fully vested and exercisable up to and through the closing of regular trading on the Nasdaq Stock Market on the fifth business day following the Acceleration Date (the "Last Exercise Date"). OTM Options not exercised on or prior to the Last Exercise Date were cancelled and ceased to exist as of the Effective Time, and no consideration was delivered in exchange for such OTM Option. |
| F5 | The securities were held directly by the David Mott Declaration of Trust dated May 31, 2001, as amended (the "Mott Trust"). The Reporting Person disclaims beneficial ownership within the meaning of Section 16 of the Securities Act of 1934, as amended, or otherwise of such portion of the securities held by the Mott Trust in which the Reporting Person has no pecuniary interest. |