X0508 4 2025-12-09 0001829802 Sensei Biotherapeutics, Inc. SNSE 0001797409 Cambrian BioPharma Inc 228 PARK AVENUE S. #66643 NEW YORK NY 10003 true false Common Stock 2025-12-09 4 S 0 3105 8.59 D 158254 D Common Stock 2025-12-09 4 S 0 2666 7.95 D 155588 D Common Stock 2025-12-09 4 M 0 395 6.4 A 155983 D Common Stock 2025-12-09 4 S 0 395 8.04 D 155588 D Common Stock 2025-12-09 4 S 0 446 7.92 D 155142 D Stock Option (Right to Buy) 6.4 2025-12-09 4 M 0 395 0 D 2035-05-20 Common Stock 395 0 D 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. These shares are held by Cambrian Biopharma, Inc., a Delaware corporation ("Cambrian"). The Chief Executive Officer of Cambrian, James Peyer, 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. 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. 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. 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. 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. Cambrian BioPharma Inc, by: /s/ James Peyer 2025-12-10