Barzolvolimab (CDX-0159) - (EMBARQ-CSU1)

September 22, 2026: Celldex (NASDAQ: CLDX) reported positive topline Phase 3 results for barzolvolimab in chronic spontaneous urticaria (CSU) from EMBARQ-CSU1 and EMBARQ-CSU2 in patients inadequately controlled by H1-antihistamines. Both trials met the primary endpoint and all key secondary endpoints at Week 12, with statistically significant improvement in UAS7 versus placebo. In CSU1, LS mean UAS7 change at Week 12 was -20.2 (150 mg Q4W) and -20.5 (300 mg Q8W) versus -10.7 for placebo; in CSU2, -20.2 and -19.7 versus -11.4 (all p<.00001).

Complete response (UAS7=0) at Week 12 was 42.4%/42.1% vs 9.3% in CSU1 and 45.7%/44.0% vs 12.6% in CSU2; by Week 24 this increased to 49.0%/45.1% vs 15.4% and 54.0%/48.4% vs 17.6% (all p<.00001). In omalizumab-refractory CSU, Week 12 UAS7=0 rates were 55.3% and 44.3% vs 9.3% in CSU1, and 41.7% and 46.4% vs 15.1% in CSU2. Angioedema resolution (AAS7=0) at Week 12 was also significantly higher versus placebo.

Treatment was well tolerated through 24 weeks. The studies continue to 52 weeks, data presentation is planned at an upcoming medical meeting, and a BLA submission is planned for 2027.