Management Change/Compensation (Form 8-K)

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On July 10, 2026, Sam Martin, Senior Vice President and Chief Financial Officer of Celldex Therapeutics, Inc. (the "Company"), notified the Company of his plans to retire effective on or about March 31, 2027. Mr. Martin joined the Company in April 2009 and has served as Chief Financial Officer since July 2017. The Company has initiated a search for a new Chief Financial Officer. To ensure a smooth transition of his responsibilities, Mr. Martin intends to continue to serve the Company as Chief Financial Officer through March 31, 2027 or until such earlier time as his successor begins to serve in such capacity.