SCHEDULE 13G 0001831942 XXXXXXXX LIVE Common Stock, par value $.001 04/03/2025 0000744218 Celldex Therapeutics, Inc. 15117B202 53 FRONTAGE ROAD SUITE 220 HAMPTON NJ 08827 Rule 13d-1(c) COMMODORE CAPITAL LP DE 0.00 3350000.00 0.00 3350000.00 3350000.00 N 5.0 IA See Item 2 for additional information. Commodore Capital Master LP E9 0.00 3350000.00 0.00 3350000.00 3350000.00 N 5.0 OO See Item 2 for additional information. Celldex Therapeutics, Inc. 53 FRONTAGE ROAD SUITE 220 HAMPTON NJ 08827 This report on Schedule 13G is being filed by Commodore Capital LP, a Delaware limited partnership (the "Firm") and Commodore Capital Master LP, a Cayman Islands exempted limited partnership ("Commodore Master"). The Firm is the investment manager to Commodore Master. As of April 3, 2025, the Firm may be deemed to beneficially own an aggregate of 3,350,000 shares of common stock, par value $.001 (the "Common Stock"), of Celldex Therapeutics, Inc. (the "Issuer"). The Firm, as the investment manager to Commodore Master, may be deemed to beneficially own these securities. Michael Kramarz and Robert Egen Atkinson are the managing partners of the Firm and exercise investment discretion with respect to these securities. Ownership percentages are based on 66,383,811 shares of Common Stock reported as issued and outstanding as of February 14, 2025 in the Issuer's Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 27, 2025. The address for the Firm and Commodore Master is: 444 Madison Avenue, Floor 35, New York, New York 10022. The Firm is a Delaware limited partnership and Commodore Master is a Cayman Islands exempted limited partnership. Y 3,350,000.00 5.0% 0.00 3,350,000.00 0.00 3,350,000.00 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 /s/ Michael Kramarz 04/10/2025 Commodore Capital Master LP /s/ Michael Kramarz 04/10/2025