Celldex Therapeutics, Inc. announced that patient enrollment has been completed in the Company’s Phase 2 clinical study of barzolvolimab for the treatment of chronic spontaneous urticaria (CSU). Barzolvolimab is a humanized monoclonal antibody that specifically binds the receptor tyrosine kinase KIT with high specificity and potently inhibits its activity, which is required for the function and survival of the mast cell. CSU is characterized by the occurrence of hives or wheals for 6 weeks or longer without identifiable specific triggers or causes.

Treatment options for patients with CSU are limited and there are no approved therapies for patients who do not respond to omalizumab. The randomized, double-blind, placebo-controlled, parallel group Phase 2 study is evaluating the efficacy and safety profile of multiple dose regimens of barzolvolimab in patients with CSU who remain symptomatic despite antihistamine therapy, to determine the optimal dosing strategy. Given strong interest in the study, enrollment projections were exceeded and 208 patients were randomly assigned on a 1:1:1:1 ratio to receive subcutaneous injections of barzolvolimab at 75 mg every 4 weeks, 150 mg every 4 weeks, 300 mg every 8 weeks or placebo during a 16-week placebo-controlled treatment phase.

After 16 weeks, patients then enter a 36-week active treatment phase, in which patients not already randomized to barzolvolimab at 150 mg every 4 weeks or 300 mg every 8 weeks are randomized 1:1 to receive one of these two dose regimens; patients already randomized to these treatment arms remain on the same regimen as during the placebo-controlled treatment phase. After 52 weeks, patients then enter a follow-up phase for an additional 24 weeks. The primary endpoint of the study is mean change in baseline to Week 12 in UAS7.

Secondary endpoints include other assessments of safety and clinical activity including ISS7, HSS7 and AAS7.