Notice of Annual Meeting of Stockholders YOUR VOTE IS IMPORTANT Regardless of whether you plan to attend the live virtual meeting, we encourage you to vote as soon as possible in one ofthe following ways: April 24, 2025Hampton, NJ Sam MartinChief Financial Officer and Secretary Pay Versus Performance Table43Director Compensation46Compensation and Organization DevelopmentCommittee Interlocks and Insider Participation47Risk Considerations47Stock Ownership Policy — Non-EmployeeDirectors47Report of The Audit Committee48Security Ownership of Certain Beneficial Ownersand Management49Transactions with Related Persons51 Information Regarding the Board ofDirectors and Corporate Governance12Independence of the Board of Directors12Board Leadership Structure12Role of the Board in Risk Oversight13Audit Committee14Compensation and Organization DevelopmentCommittee14Nominating and Corporate GovernanceCommittee15Science and Regulatory Committee15Director selection criteria15Board Diversity MatrixStockholder nominations for directorships17Stockholder Communications17Code of Business Conduct and Ethics17Corporate Governance Matters18Compliance Program18Stock Ownership Guidelines18Insider Trading Policy (including Anti-Hedging andAnti-Pledging)18 Proposal 2: Ratification of IndependentPublic Accounting Firm52 Principal Accountant Fees and Services52Audit Fees52All Other Fees52 Proposal 3: Approval of an Amendmentto the 2021 Omnibus Equity IncentivePlan54 Environmental, Social and Governance19 Proposal 4: Advisory Vote on ExecutiveCompensation60 About Us Celldex is a clinical stage biotechnology company leading the science at the intersection of mast cell biology and thedevelopment of transformative therapeutics for patients. Our Pipeline Our pipeline includes antibody-based therapeutics which have the ability to engage the human immune system and/ordirectly affect critical pathways to improve the lives of patients with severe inflammatory, allergic and autoimmune andother devastating diseases. BISPECIFIC PLATFORM- Next Generation Inflammatory Candidates CDX-622 Barzolvolimab Barzolvolimab is a humanized monoclonal antibody thatbinds the receptor tyrosine kinase KIT with highspecificity and potently inhibits its activity. KIT isexpressed in a variety of cells, including mast cells, whichmediate inflammatory responses such ashypersensitivity and allergic reactions. KIT signalingcontrols the differentiation, tissue recruitment, survivaland activity of mast cells. In certain inflammatorydiseases, such as chronic urticaria, mast cell activationplays a central role in the onset and progression of thedisease. Barzolvolimab is currently being studied inchronic spontaneous urticaria (CSU), chronic inducibleurticaria (CIndU), prurigo nodularis (PN), eosinophilicesophagitis (EOE) and atopic dermatitis (AD), withadditional indications planned for the future. Targets two complementary pathways that drivechronic inflammation, potently neutralizing thealarmin thymic stromal lymphopoietin (TSLP) anddepleting mast cells via stem cell factor (SCF)starvation. Combined neutralization of SCF and TSLPwith CDX-622 is expected to simultaneously reducetissue mast cells and inhibit Type 2 inflammatoryresponses to potentially offer enhanced therapeuticbenefit in inflammatory and fibrotic disorders. Our Science Driven by our deep and longstanding experience developing antibody-based immunotherapies, Celldex’s proprietaryantibody programs and technologies are supported by robust in-house capabilities, enabling the optimized discovery anddevelopment of innovative scientific programs. Deep and longstandingexperience developingantibody-basedimmunotherapies Proprietary antibodyprograms using validatedtechnologies driveinnovation Cutting edge sciencewith patient-focusedapproach Robust in-housecapabilities enableoptimized developmentprocess Proxy Statement Proxy Statement This proxy statement contains information related to the Annual Meeting of Stockholders to be held on June 5, 2025 at9:00 a.m. Eastern Time. We are holding the Annual Meeting virtually via the Internet. In order to attend our Annual Meeting,you must log in to www.virtualshareholdermeeting.com/CLDX2025 using the 16-digit control number on the notice,proxy card or voting instruction form that accompanied the proxy materials. Our Annual Meeting could be adjourned or postponed to another date and/or time. A list of record holders of theCompany’s common stock entitled to vote at the Annual Meeting will be available for examination by any stockholder, forany purpose germane to the Annual Meeting, at our principal offices at Perryville III Building, 53 Frontage Road, Suite 220,Hampton, New Jersey 08827, during normal business hours for ten days prior to the Annual Meeting. The enclosed proxy is solicited by the Board of Directors of Celldex Therapeutics, Inc. (the “Board”). The proxy materialsrelating to the Annual Meeting are being mailed to stockholders entitled to v