X0609 4 2026-05-07 0001882782 Odyssey Therapeutics, Inc. ODTX 0001242825 LEIDEN JEFFREY M false C/O ODYSSEY THERAPEUTICS, INC. 51 SLEEPER STREET, SUITE 800 BOSTON MA 02210 true false false false false Common Stock 2026-05-08 4 P false 5000 20.00 A 270198 D Common Stock 2026-05-11 4 C false 28698 A 28698 I See footnote Common Stock 2026-05-11 4 M false 2963 A 31661 I See footnote Common Stock 2026-05-11 4 F false 17 18.00 D 31644 I See footnote Series B Convertible Preferred Stock 2026-05-11 4 C false 79166 D Common Stock 8527 0 I See footnote Series C Convertible Preferred Stock 2026-05-11 4 C false 100000 D Common Stock 10291 0 I See footnote Series D Convertible Preferred Stock 2026-05-11 4 C false 96002 D Common Stock 9880 0 I See footnote Stock Option (Right to Buy) 18.00 2026-05-07 4 A false 626220 0 A 2036-05-06 Common Stock 626220 626220 D Series D Warrants (Right to Buy) 0.10 2026-05-11 4 M false 28800 D Common Stock 2963 0 I See footnote The Series B Preferred Stock automatically converted into Common Stock immediately prior to the closing of the Issuer's initial public offering on a 1-for-9.2837 basis for no additional consideration. The Series C Preferred Stock automatically converted into Common Stock immediately prior to the closing of the Issuer's initial public offering on a 1-for-9.7170 basis for no additional consideration. The Series D Preferred Stock automatically converted into Common Stock immediately prior to the closing of the Issuer's initial public offering on a 1-for-9.7170 basis for no additional consideration. These securities are held of record by Racing Beach Ventures LLC ("Racing Beach"). The Reporting Person is a managing member of Racing Beach and may be deemed to have beneficial ownership of the securities. The warrants to purchase shares of Common Stock were automatically exercised into shares of Common Stock by their terms immediately prior to the closing of the Issuer's initial public offering on a net exercise basis. Pursuant to the terms of the warrants, the Issuer withheld 17 warrant shares to pay the exercise price in connection with the net exercise. Gives effect to the 1-for-9.7170 reverse stock split effected prior to the closing of the Issuer's initial public offering. Option will vest in full on May 7, 2027, subject to the Reporting Person's continued service on each such vesting date. /s/ Jolie M. Siegel, Attorney-in-Fact 2026-05-11