Celldex Therapeutics Inc. (NASDAQ:CLDX) on Tuesday said it is ending its Phase 2 clinical trial evaluating barzolvolimab for prurigo nodularis, a chronic condition characterized by intensely itchy skin nodules.
The discontinuation comes after the study failed to achieve its primary and key secondary objectives.
Suboptimal Clinical Outcomes
The 24-week, double-blind, placebo-controlled study enrolled 140 participants with moderate to severe symptoms who lacked adequate responses to topical medications.
The trial’s primary goal was to observe a four-point or greater improvement on the worst itch numeric rating scale at the 12-week mark.
The percentage of patients reaching this milestone showed no meaningful differentiation from the placebo group.
Secondary targets, including the investigator global assessment for skin lesions, were equally unsuccessful. Furthermore, extending the active treatment and evaluation period to 24 weeks yielded no additional clinical improvements.
Biological Impact And Safety Profile
Barzolvolimab is a novel humanized monoclonal antibody designed to target and deplete mast cells.
The treatment successfully triggered a rapid, profound, and sustained reduction in circulating tryptase, clearly confirming systemic mast cell depletion.
However, this biological response did not translate into symptom relief, leading researchers to conclude that mast cells may not be the central pathogenic driver of prurigo nodularis.
Despite the lack of clinical efficacy, the drug remained extremely well-tolerated.
The administered regimen, featuring an initial 450mg loading dose followed by ongoing 150mg or 300mg doses every four weeks, maintained a favorable safety profile consistent with previous clinical observations.
Following the main phase, patients were monitored for an additional 16 weeks, though the primary investigation is now halted.
In August 2025, Celldex stopped developing barzolvolimab in eosinophilic esophagitis (EoE) as the drug did not improve EoE symptoms or endoscopic assessment of disease activity compared to placebo.
CLDX Price Action: Celldex Therapeutics shares were down 6.06% at $33.50 during premarket trading on Wednesday, according to Benzinga Pro data.
Photo by Pavel Kapysh via Shutterstock
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