Lauren Merendino - 23 Apr 2026 Form 4 Insider Report for Day One Biopharmaceuticals, Inc. (DAWN)

Reporting relationship: Chief Commercial Officer
Issuer ticker: DAWN
Reported as of: 23 Apr 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 23 Apr 2026, 16:30:00 UTC
Prior SEC filing: 18 Feb 2026
Source filing: View source filing
Reporting owner signature: /s/ Charles N. York II, as Attorney-in-Fact

Key filing fact

Lauren Merendino filed Form 4 for Day One Biopharmaceuticals, Inc. (DAWN) on 23 Apr 2026.

Key facts

This page summarizes Lauren Merendino's Form 4 filing for Day One Biopharmaceuticals, Inc. (DAWN).
9 reported transactions and 8 derivative rows are listed below.
Accepted by SEC: 23 Apr 2026, 16:30.

Change

Previous filing in this sequence was filed on 18 Feb 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001855298 Primary reporting owner

Merendino Lauren

Relationship: Chief Commercial Officer
Address: 1800 SIERRA POINT PARKWAY, SUITE 200, BRISBANE
Signature: /s/ Charles N. York II, as Attorney-in-Fact
Signature date: 23 Apr 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

DAWN transaction

Common Stock

Disposed to Issuer

Transaction value
Shares: -60,157
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Footnotes: F1, F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

DAWN transaction Derivative

Stock Option (right to buy Common Stock)

Disposed to Issuer

Transaction value
Shares: -330,200
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 330,200
Exercise price: $8.99
Footnotes: F3, F4

DAWN transaction Derivative

Stock Option (right to buy Common Stock)

Disposed to Issuer

Transaction value
Shares: -90,000
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 90,000
Exercise price: $8.99
Footnotes: F4, F5

DAWN transaction Derivative

Stock Option (right to buy Common Stock)

Disposed to Issuer

Transaction value
Shares: -90,000
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 90,000
Exercise price: $8.99
Footnotes: F4, F6

DAWN transaction Derivative

Stock Option (right to buy Common Stock)

Disposed to Issuer

Transaction value
Shares: -110,000
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 110,000
Exercise price: $11.16
Footnotes: F4, F7

DAWN transaction Derivative

Restricted Stock Unit (RSU)

Disposed to Issuer

Transaction value
Shares: -18,978
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 18,978
Exercise price
Footnotes: F4, F8, F9, F10

DAWN transaction Derivative

Restricted Stock Unit (RSU)

Disposed to Issuer

Transaction value
Shares: -25,816
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 25,816
Exercise price
Footnotes: F4, F8, F10, F11

DAWN transaction Derivative

Restricted Stock Unit (RSU)

Disposed to Issuer

Transaction value
Shares: -40,565
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 40,565
Exercise price
Footnotes: F4, F8, F10, F11

DAWN transaction Derivative

Restricted Stock Unit (RSU)

Disposed to Issuer

Transaction value
Shares: -69,375
Change %: -100%
Price
Shares after: 0
Date: 23 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 69,375
Exercise price
Footnotes: F4, F8, F10, F11

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Section 16 status

Lauren Merendino is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may still apply in specific circumstances.

Explanation of responses 11 footnotes

Footnote F1

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.

Footnote F2

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.

Footnote F3

The option vests as to 25% of the total shares on June 12, 2024 and then 2.0833% of the total shares vest monthly thereafter, with 100% of the total shares vested on June 12, 2027, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

Footnote F4

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.

Footnote F5

The option vests as to 1/48th of the total shares monthly, commencing February 5, 2024, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

Footnote F6

The option vests as to 1/48th of the total shares monthly, commencing February 15, 2025, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

Footnote F7

The option vests as to 1/48th of the total shares monthly, commencing February 28, 2026, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

Footnote F8

Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock upon settlement for no consideration.

Footnote F9

The RSUs vested as to 1/4th of the total award on August 15, 2024, and the remaining 3/4 of the award vests in 12 substantially equal quarterly installments thereafter on November 15, February 15, May 15 and August 15, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

Footnote F10

RSUs do not expire; they either vest or are canceled prior to the vesting date.

Footnote F11

The RSUs vest as to 1/16th of the total award in quarterly installments on February 15, May 15, August 15 and November 15, subject to the Reporting Person's provision of service to the Issuer on each vesting date.