X0306 4 2021-02-08 0 0001829802 Sensei Biotherapeutics, Inc. SNSE 0001797409 Cambrian BioPharma Inc 19 MORRIS AVE BROOKLYN NAVY YARD BUILDING, 128 BROOKLYN NY 11025 0 0 1 0 Common Stock 2021-02-08 4 C 0 2407328 A 4690153 D Series AA Preferred Convertible Stock 2021-02-08 4 P 0 110729827 0.00 D Common Stock 2306870 0 D Series BB Preferred Convertible Stock 2021-02-08 4 C 0 4821996 0.00 D Common Stock 100458 0 D The total represents shares received upon conversion of shares of Series AA Preferred Stock and Series BB Preferred Stock. Each share of the Series AA Preferred Stock and Series BB Preferred Stock converted to 0.0208333 shares of the Issuer's common stock, effective immediately prior to the closing of the Issuer's initial public offering of its common stock. The Series AA Preferred Stock and Series BB Preferred Stock haves no expiration date. 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. Cambrian Biopharma, Inc. By: /s/James Peyer 2021-02-10