James Peyer - 09 Dec 2025 Form 4 Insider Report for Sensei Biotherapeutics, Inc. (SNSE)

Role: Other*, 10%+ Owner
Signature: /s/ James Peyer
Issuer symbol: SNSE
Transactions as of: 09 Dec 2025
Net transactions value: -$52,047
Form type: 4
Filing time: 10 Dec 2025, 16:52:32 UTC
Previous filing: 08 Dec 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Peyer James	Other*, 10%+ Owner	228 PARK AVENUE S., #66643, NEW YORK	/s/ James Peyer	10 Dec 2025	0001843594

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SNSE	Common Stock	Sale	$26,672	-3,105	-1.9%	$8.59	158,254	08 Dec 2025	See footnote	F1, F2
transaction	SNSE	Common Stock	Sale	$21,195	-2,666	-1.7%	$7.95	155,588	09 Dec 2025	See footnote	F2, F3
transaction	SNSE	Common Stock	Options Exercise	$2,528	+395	+0.25%	$6.40	155,983	09 Dec 2025	See footnote	F2
transaction	SNSE	Common Stock	Sale	$3,176	-395	-0.25%	$8.04	155,588	09 Dec 2025	See footnote	F2
transaction	SNSE	Common Stock	Sale	$3,532	-446	-0.29%	$7.92	155,142	09 Dec 2025	See footnote	F2, F4

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	SNSE	Stock Option (Right to Buy)	Options Exercise	$0	-395	-100%	$0.000000	0	09 Dec 2025	Common Stock	395	$6.40	Direct	F5, F6

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The price reported in Column 4 is a weighted average price. The prices sold ranged from $8.50 to $9.00. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range.
F2	These shares are held by Cambrian Biopharma Inc, a Delaware corporation ("Cambrian"). The Reporting Person is the Chief Executive Officer of Cambrian and in such capacity may direct the voting and disposition of the shares held by Cambrian, subject in certain instances to the approval of Cambrian's Board of Directors. Mr. Peyer disclaims beneficial ownership of such shares.
F3	The price reported in Column 4 is a weighted average price. The prices sold ranged from $7.80 to $8.33. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range.
F4	The price reported in Column 4 is a weighted average price. The prices sold ranged from $7.91 to $7.95. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range.
F5	The amount shown reflects the number of shares held following the reported transaction, as adjusted for a 1-for-20 stock split effectuated by the issuer.
F6	The shares subject to the option vest and become exercisable in 12 equal monthly installments over a one year period such that the option is fully vested on the first anniversary of the date of grant, or May 21, 2026, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date; provided that the option will in any case be fully vested on the date of the Company's next annual stockholder meeting, subject to the Reporting Person's continuous service with the Issuer through such vesting date.