Celldex presents histology data from barzolvolimab study

Celldex (CLDX) announced the presentation of histology data from the company’s ongoing Phase 2 study of barzolvolimab in eosinophilic esophagitis. Biopsies taken during screening demonstrate the presence of high numbers of intraepithelial mast cells in participants with active EoE and correlate with eosinophil counts, supporting the hypothesis that treating EoE with barzolvolimab-a mast cell depleting agent-could provide promising therapeutic benefit. The data were discussed in a poster presentation at the Digestive Disease Week 2025 conference in San Diego. Celldex announced in February that enrollment to the Phase 2 study is complete and that clinical results are expected in the second half of 2025. Ongoing 28-week, randomized, double-blind, placebo controlled study evaluating 300 mg of barzolvolimab or placebo administered every 4 weeks in participants with known EoE. Eligible participants have at least 15 eosinophils per high power field in 2 of 3 segments of the esophagus and at least 4 dysphagia days in the 2 weeks prior to baseline. Primary endpoint is reduction in peak esophageal epithelial mast cell count cell at 12 weeks, with key secondary endpoints of reduction in peak eosinophil count and reduction in DSQ at 12 weeks. Pinch biopsies from 151 screened participants were obtained at screening from three different esophageal segments. Screening histology data from this trial demonstrate that high numbers of intraepithelial mast cells are present in participants with active EoE and correlate with eosinophil counts: Intraepithelial mast cells and eosinophil counts per hpf from screening biopsies were enumerated by IHC and H&E staining. Similar numbers of cells were observed across the three biopsy sites, with a trend towards greater numbers in the distal esophagus. Participants who failed screening due to low eosinophil counts also tended to have lower tryptase+ and CD117+ mast cell counts. Pearson correlations show an association between both CD117+ or tryptase+ total and peak mast cells and eosinophils, as well as between CD117+ and tryptase+ total and peak mast cells. Patients are currently completing treatment and the follow up phase on study; clinical data from the study is expected to be presented in the second half of 2025.