X0202 SCHEDULE 13G/A 0001831942-25-000022 0001831942 XXXXXXXX LIVE 1 Common Stock, $0.0001 par value 6/30/2026 0001503802 Karyopharm Therapeutics Inc. 48576U205 85 Wells Avenue 2nd Floor Newton MA 02459 Rule 13d-1(c) Commodore Capital LP DE 0.00 0.00 0.00 0.00 0.00 0.0 IA PN Commodore Capital Master LP E9 0.00 0.00 0.00 0.00 0.00 0.0 PN Robert Egen Atkinson X1 0.00 0.00 0.00 0.00 0.00 0.0 HC IN Michael Kramarz X1 0.00 0.00 0.00 0.00 0.00 0.0 HC IN Karyopharm Therapeutics Inc. 85 Wells Avenue, 2nd Floor, Newton, MASSACHUSETTS, 02459. Commodore Capital LP Commodore Capital Master LP Robert Egen Atkinson Michael Kramarz Each a "Filer." The address for Commodore Capital LP, Robert Egen Atkinson, and Michael Kramarz is 444 Madison Avenue, Floor 35, New York, NY 10022. The address for Commodore Capital Master LP is c/o Maples Corporate Services Limited, Ugland House, South Church Street, PO Box 309, Grand Cayman KY1-1104, Cayman Islands. See Item 4 of the cover page for each Filer. Y See Item 9 of the cover page for each Filer. See Item 11 of the cover page for each Filer. See Item 5 of the cover page for each Filer. See Item 6 of the cover page for each Filer. See Item 7 of the cover page for each Filer. See Item 8 of the cover page for each Filer. Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11. Exhibit 1: Joint Filing Agreement Commodore Capital LP Michael Kramarz 08/14/2026 Commodore Capital Master LP Michael Kramarz 08/14/2026 Robert Egen Atkinson Robert Egen Atkinson 08/14/2026 Michael Kramarz Michael Kramarz 08/14/2026