CDX-0159 is a humanized monoclonal antibody that specifically binds the receptor tyrosine kinase KIT and potently inhibits its activity. KIT is expressed in a variety of cells, including mast cells, and its activation by its ligand SCF regulates mast cell functions including activation and survival. In certain inflammatory diseases, such as chronic idiopathic urticaria (CIU), also known as chronic spontaneous urticaria (CSU), mast cell activation plays a central role in the onset and progression of the disease. In a Phase 1 clinical study with our KIT antagonist monoclonal antibody, CDX-0158, robust inhibition of mast cell activity was observed supporting the concept that targeting KIT can modulate mast cell activity and potentially provide clinical benefit in mast cell related diseases. CDX-0158 was re-engineered and replaced with CDX-0159, a New Molecular Entity (NME), to ablate Fc receptor interactions and effector function and improve its safety profile, while preserving full KIT inhibitory activity. In addition, CDX-0159 was modified to provide extended half-life following administration.

Ongoing Clinical Trials

CDX-0159 is currently in a Phase 1a study designed to evaluate the safety profile, pharmacokinetics and pharmacodynamics of single ascending doses in healthy subjects. Following completion of this study, Celldex plans to further study CDX-0159 in CIU, a mast cell-related disease. CIU presents as itchy hives, angioedema or both for at least six weeks without a specific trigger; multiple episodes can play out over years or even decades. The prevalence of CIU is estimated to be 0.5% to 1% of the total population or up to 3.2 million cases in the United States. About 50% of patients with CIU achieve symptomatic control with antihistamines or leukotriene receptor antagonists. Omalizumab, an IgE inhibitor, provides relief for roughly half of the remaining antihistamine/leukotriene refractory patients. Consequently, there is a need for more effective later line therapies. A review of the CDX-0159 early development program was presented at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting in November 2019.

For more information on the CDX-0159 program, view recent scientific presentations and publications.