Day One Biopharma insider granted 309k options; repricing at $8.99

Rhea-AI Filing Summary

Day One Biopharmaceuticals (DAWN) filed a Form 4 for its General Counsel & Secretary. On 11/06/2025, the officer was granted a stock option for 309,000 shares at an exercise price of $8.99, vesting 100% on November 6, 2026.

The filing also records an option repricing approved on October 7, 2025 and effective November 6, 2025: three existing options covering 90,000 shares each were canceled at prior exercise prices of $23.41, $14.44, and $11.87 and replaced with options at $8.99, keeping original expirations in 2033–2035 and monthly vesting schedules. To exercise at the new price, service through the Retention Period is required, which ends at the earlier of the 12‑month anniversary of the Effective Date or a Corporate Transaction.

Insider Trade Summary

7 transactions reported

Mixed 7 txns

Insider Dubow Adam

Role Gen Counsel & Secretary

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy Common Stock)	309,000	$0.00	--
Disposition	Stock Option (right to buy Common Stock)	90,000	$0.00	--
Grant/Award	Stock Option (right to buy Common Stock)	90,000	$0.00	--
Disposition	Stock Option (right to buy Common Stock)	90,000	$0.00	--
Grant/Award	Stock Option (right to buy Common Stock)	90,000	$0.00	--
Disposition	Stock Option (right to buy Common Stock)	90,000	$0.00	--
Grant/Award	Stock Option (right to buy Common Stock)	90,000	$0.00	--

Holdings After Transaction: Stock Option (right to buy Common Stock) — 309,000 shares (Direct)

Footnotes (1)

1. The option vests as to 100% of the total shares on November 6, 2026, subject to the Reporting Person's provision of service to the Issuer on such vesting date. On October 7, 2025, the Issuer's Board of Directors approved an option repricing (the "Repricing") whereby the Reporting Person's options were repriced on November 6, 2025 (the "Effective Date") with a new exercise price of $8.99 (if lower than the original exercise price), the closing price on Nasdaq as of the Effective Date. In order to exercise the repriced options at the new exercise price, the Reporting Person is required to remain in service with the Issuer through the Retention Period; provided that the additional premium payment will not be required if the Reporting Person's service to the Issuer is terminated by reason of death or Disability (as defined in the Company's 2021 Equity Incentive Plan ("the Plan")). (Continued from Footnote 2) The "Retention Period" commenced on the Effective Date and ends upon the earliest of (i) the 12-month anniversary of the Effective Date and (ii) a Corporate Transaction (as defined in the Plan). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable. The option vests as to 1/48th of the total shares monthly, commencing February 17, 2023, subject to the Reporting Person's provision of service to the Issuer on each vesting date. 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. 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.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Dubow Adam

(Last) (First) (Middle)

1800 SIERRA POINT PARKWAY, SUITE 200

(Street)

BRISBANE CA 94005

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Day One Biopharmaceuticals, Inc. [ DAWN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Gen Counsel & Secretary

3. Date of Earliest Transaction (Month/Day/Year)
11/06/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A		309,000		(1)	10/30/2032	Common Stock	309,000	$0	309,000	D
Stock Option (right to buy Common Stock)	$23.41	11/06/2025		D(2)(3)			90,000	(4)	01/16/2033	Common Stock	90,000	$0	0	D
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A(2)(3)		90,000		(4)	01/16/2033	Common Stock	90,000	$0	90,000	D
Stock Option (right to buy Common Stock)	$14.44	11/06/2025		D(2)(3)			90,000	(5)	01/04/2034	Common Stock	90,000	$0	0	D
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A(2)(3)		90,000		(5)	01/04/2034	Common Stock	90,000	$0	90,000	D
Stock Option (right to buy Common Stock)	$11.87	11/06/2025		D(2)(3)			90,000	(6)	01/14/2035	Common Stock	90,000	$0	0	D
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A(2)(3)		90,000		(6)	01/14/2035	Common Stock	90,000	$0	90,000	D

Explanation of Responses:

1. The option vests as to 100% of the total shares on November 6, 2026, subject to the Reporting Person's provision of service to the Issuer on such vesting date.

2. On October 7, 2025, the Issuer's Board of Directors approved an option repricing (the "Repricing") whereby the Reporting Person's options were repriced on November 6, 2025 (the "Effective Date") with a new exercise price of $8.99 (if lower than the original exercise price), the closing price on Nasdaq as of the Effective Date. In order to exercise the repriced options at the new exercise price, the Reporting Person is required to remain in service with the Issuer through the Retention Period; provided that the additional premium payment will not be required if the Reporting Person's service to the Issuer is terminated by reason of death or Disability (as defined in the Company's 2021 Equity Incentive Plan ("the Plan")).

3. (Continued from Footnote 2) The "Retention Period" commenced on the Effective Date and ends upon the earliest of (i) the 12-month anniversary of the Effective Date and (ii) a Corporate Transaction (as defined in the Plan). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

4. The option vests as to 1/48th of the total shares monthly, commencing February 17, 2023, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

5. 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.

6. 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.

	/s/ Charles N. York II, as Attorney-in-Fact	11/07/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did DAWN's officer report on Form 4?

A grant of 309,000 stock options at $8.99 on 11/06/2025, plus a repricing of three option tranches to $8.99.

What are the vesting terms for the new 309,000-share option?

It vests as to 100% of the shares on November 6, 2026, subject to continued service.

Which options were repriced for DAWN and to what price?

Three options of 90,000 shares each were repriced to $8.99, replacing prior prices of $23.41, $14.44, and $11.87.

When was the option repricing approved and effective?

Approved on October 7, 2025 and effective on November 6, 2025.

What is the Retention Period condition related to the repricing?

Service through the Retention Period is required; it ends at the earlier of the 12-month anniversary of the Effective Date or a Corporate Transaction.

What are the expirations for the repriced options?

They retain expirations in 2033, 2034, and 2035, with monthly vesting per the original schedules.