Celldex Therapeutics Inc

Celldex Therapeutics, Inc., which we refer to as "Celldex," "we," "us," "our" or the "Company," is a biopharmaceutical company dedicated to exploring the science of mast cell biology and developing therapeutic antibodies which have the ability to engage the human immune system and/or directly affect critical pathways to improve the lives of patients with severe inflammatory, allergic, autoimmune and other devastating diseases. Our drug candidates include monoclonal and bispecific antibodies designed to address mast cell mediated diseases for which available treatments are inadequate.

We are focusing our efforts and resources on the continued research and development of

Barzolvolimab (also referred to as CDX-0159), a monoclonal antibody that specifically binds the KIT receptor and potently inhibits its activity, which is currently being studied across multiple mast cell driven diseases including

Chronic Spontaneous Urticaria (CSU): In February 2026, we announced that enrollment is complete in our Phase 3 studies in CSU and that topline data will be available in the fourth quarter of 2026. In November 2023, we announced that our Phase 2 study in CSU achieved the primary efficacy endpoint (statistically significant mean change from baseline to Week 12 of urticaria activity score compared to placebo) and was well tolerated. Patients on study continued to receive barzolvolimab and, in September 2024, we reported data from 52 weeks of treatment—demonstrating sustained and deepening disease efficacy and a well tolerated long term safety profile. In June 2025, Celldex presented longer term follow up data from the study. At 76 weeks, 7 months after the completion of dosing with barzolvolimab, over 40% of patients (150 mg Q4W) continued to experience profound, sustained complete response and improved quality of life;