Director at Sensei Biotherapeutics (SNSE) receives 23,100 stock options

Rhea-AI Filing Summary

Sensei Biotherapeutics director Phillip B. Donenberg received a supplemental stock option grant for 23,100 shares of Common Stock. The option has an exercise price of $29.89 per share and expires on April 9, 2036. This award aligns his total initial director option grant with the company’s amended non-employee director compensation policy, which now provides 25,000 options to new directors. The new options vest in 36 equal monthly installments over three years, fully vesting on April 10, 2029, contingent on his continued service as a director.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Donenberg Phillip B.

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	23,100	$0.00	--

Holdings After Transaction: Stock Option (right to buy) — 23,100 shares (Direct)

Footnotes (1)

1. Represents a supplemental option grant to align the Reporting Person's total initial director option grant with the Company's non-employee director compensation policy, which was amended on April 10, 2026 to provide for an initial option grant of 25,000 shares to new directors. The Reporting Person previously received an initial grant of 1,900 shares in February 2026; this supplemental grant of 23,100 shares reflects the difference. The shares subject to the option vest and become exercisable in 36 equal monthly installments over a three year period such that the option is fully vested on the third anniversary of the date of grant, or April 10, 2029, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date.

Key Figures

Supplemental option grant: 23,100 shares Exercise price: $29.89 per share Expiration date: April 9, 2036 +4 more

7 metrics

Supplemental option grant 23,100 shares Stock Option (right to buy) granted on April 10, 2026

Exercise price $29.89 per share Stock option strike price for 23,100-share grant

Expiration date April 9, 2036 Option term end date

Vesting schedule 36 equal monthly installments Fully vested by April 10, 2029, subject to continued service

Prior initial grant 1,900 shares Initial option grant received in February 2026

Policy initial grant level 25,000 shares Non-employee director compensation policy initial option grant

Total options after grant 23,100 shares Total stock option holdings reported following this transaction

Key Terms

supplemental option grant, non-employee director compensation policy, vest and become exercisable, continuous service, +1 more

5 terms

supplemental option grant financial

"Represents a supplemental option grant to align the Reporting Person's total initial director option grant"

non-employee director compensation policy financial

"the Company's non-employee director compensation policy, which was amended on April 10, 2026"

vest and become exercisable financial

"The shares subject to the option vest and become exercisable in 36 equal monthly installments"

continuous service financial

"subject to the Reporting Person's continuous service with the Issuer as of each such vesting date"

Stock Option (right to buy) financial

"security_title: Stock Option (right to buy)"

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^*

Donenberg Phillip B.

(Last) (First) (Middle)

C/O SENSEI BIOTHERAPEUTICS, INC.

1405 RESEARCH BLVD, SUITE 125

(Street)

ROCKVILLE MARYLAND 20850

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Sensei Biotherapeutics, Inc. [ SNSE ]

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

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/10/2026

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

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

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

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)	$29.89	04/10/2026		A(1)		23,100		(2)	04/09/2036	Common Stock	23,100	$0	23,100	D

Explanation of Responses:

1. Represents a supplemental option grant to align the Reporting Person's total initial director option grant with the Company's non-employee director compensation policy, which was amended on April 10, 2026 to provide for an initial option grant of 25,000 shares to new directors. The Reporting Person previously received an initial grant of 1,900 shares in February 2026; this supplemental grant of 23,100 shares reflects the difference.

2. The shares subject to the option vest and become exercisable in 36 equal monthly installments over a three year period such that the option is fully vested on the third anniversary of the date of grant, or April 10, 2029, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date.

Remarks:

Exhibit 24 - Power of Attorney

	/s/ Phillip B. Donenberg	04/14/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What did Sensei Biotherapeutics (SNSE) director Phillip Donenberg receive in this Form 4?

Phillip B. Donenberg received a supplemental stock option grant for 23,100 shares of Sensei Biotherapeutics Common Stock. These options were awarded as part of his non-employee director compensation and are intended to align his initial grant with the company’s updated director equity policy.

Why was the 23,100-share option grant made to the SNSE director?

The 23,100-share option grant is a supplemental award to align Donenberg’s total initial director option grant with Sensei Biotherapeutics’ amended non-employee director compensation policy. The policy now provides 25,000 initial option shares to new directors, and he previously received 1,900 shares in February 2026.

What are the vesting terms of Phillip Donenberg’s new SNSE stock options?

The options vest and become exercisable in 36 equal monthly installments over three years, fully vesting on April 10, 2029. Vesting is subject to Donenberg’s continuous service with Sensei Biotherapeutics as a director on each monthly vesting date, tying the award to ongoing board service.

What is the exercise price and expiration date of the SNSE director’s options?

The stock options have an exercise price of $29.89 per share and expire on April 9, 2036. This means Donenberg can purchase up to 23,100 shares at $29.89 each any time after vesting and before expiration, subject to the plan’s terms and conditions.

How does this Form 4 change the SNSE director’s option holdings?

Following this grant, Donenberg holds 23,100 stock options as reported in the filing. Combined with his earlier 1,900-share grant, the total initial director option allocation now matches Sensei Biotherapeutics’ amended policy of 25,000 option shares for new non-employee directors.