X0609 4 2026-04-23 1 0001845337 Day One Biopharmaceuticals, Inc. DAWN 0001547959 Ramasastry Saira false 1800 SIERRA POINT PARKWAY, SUITE 200 BRISBANE CA 94005 true false false false 0 Common Stock 2026-04-23 4 D 0 40485 D 0 D Stock Option (right to buy Common Stock) 8.99 2026-04-23 4 D 0 40000 D 2031-05-25 Common Stock 40000 0 D Stock Option (right to buy Common Stock) 8.99 2026-04-23 4 D 0 47581 D 2031-05-25 Common Stock 47581 0 D Stock Option (right to buy Common Stock) 8.99 2026-04-23 4 D 0 28700 D 2032-06-20 Common Stock 28700 0 D Stock Option (right to buy Common Stock) 8.99 2026-04-23 4 D 0 37500 D 2033-06-21 Common Stock 37500 0 D Stock Option (right to buy Common Stock) 8.99 2026-04-23 4 D 0 32335 D 2034-05-22 Common Stock 32335 0 D Stock Option (right to buy Common Stock) 7.01 2026-04-23 4 D 0 22500 D 2035-06-01 Common Stock 22500 0 D Restricted Stock Unit (RSU) 2026-04-23 4 D 0 15000 D Common Stock 15000 0 D On March 6, 2026, Servier Pharmaceuticals LLC, a Delaware limited liability company ("Parent"), Servier Detroit Inc., a Delaware corporation and a wholly owned subsidiary of Parent ("Merger Sub"), Day One Biopharmaceuticals, Inc., a Delaware corporation (the "Company"), and Servier S.A.S., a French societe par actions simplifiee, solely as a guarantor, entered into an Agreement and Plan of Merger (the "Merger Agreement"). Pursuant to the Merger Agreement, the Merger Sub merged with and into the Company (such merger and the other transactions contemplated by the Merger Agreement, the "Merger") with the Company surviving the Merger as a wholly owned subsidiary of the Parent. Upon the closing of the Merger on April 23, 2026, each issued and outstanding share of the Company's Common Stock, par value $0.0001 per share, was either (x) purchased for $21.50 per share (the "Offer Price"), net to the seller in cash, without interest, and subject to applicable withholding taxes, on the terms and conditions set forth in the Merger Agreement, or (y) automatically converted into the right to receive the Offer Price (the "Merger Consideration"), net to the seller in cash, without interest, and subject to applicable withholding taxes, on the terms and conditions set forth in the Merger Agreement. The options are fully vested. Immediately prior to the effective time of the Merger, all outstanding unvested stock options and unvested restricted stock units became fully vested. At the effective time of the Merger, each stock option and restricted stock unit was canceled and converted into the right to receive an amount in cash equal to the Merger Consideration (or, in the case of stock options, the difference between the Merger Consideration and the applicable per share exercise price), less any applicable withholding taxes. The option vests as to 1/12th of the total grant on each monthly anniversary, beginning on July 2, 2025, subject to the Reporting Person's provision of service to the Issuer on each option vesting date. Each restricted stock unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock upon settlement for no consideration. The RSUs will vest as to 100% of the award on the earlier of (i) June 2, 2026 and (ii) the date of the Issuer's 2026 annual meeting of stockholders (in each case, the "RSU Vesting Date"), subject to the Reporting Person's provision of services to the Issuer on each vesting date. On the RSU Vesting Date, pursuant to the Reporting Person's election, the RSUs will automatically convert into an equal number of deferred stock units, which will be settled for an equal number of shares of the Issuer's Common Stock on the earlier of the calendar year 2030 or the Reporting Person's separation with the Issuer. Notwithstanding the aforementioned deferral period, from and after the RSU Vesting Date, the deferred stock units may settle earlier upon the Reporting Person's death, disability, or separation from service with the Issuer, or upon the occurrence of an "unforeseeable emergency," as that term is defined under the Issuer's deferred compensation plan. RSUs do not expire; they either vest or are canceled prior to the RSU Vesting Date. /s/ Charles N. York II, as Attorney-in-Fact 2026-04-23