Celldex’s Chronic Urticaria Drug Succeeds in Two Phase 3 Trials, Seeks Comeback

Celldex’s antibody drug candidate barzolvolimab met its goals in two phase 3 trials involving patients with chronic spontaneous urticaria (CSU) who did not respond to existing treatments.

According to Fierce Biotech, a U.S. biotechnology news outlet, on the 22nd local time, Celldex said it met all primary and secondary endpoints in the Embark CSU1 and CSU2 trials involving patients with treatment-refractory CSU.

Barzolvolimab is a monoclonal antibody that binds to and inhibits the activity of KIT, a receptor tyrosine kinase expressed on mast cells. Abnormal activation of mast cells is known to be a major cause of hives and swelling accompanied by itching in CSU.

The two trials were randomized, double-blind, placebo-controlled global studies involving a total of 1939 participants. Patients received barzolvolimab 150 mg every 4 weeks or 300 mg every 8 weeks for 52 weeks, or placebo for 24 weeks.

At week 12, measurements using the weekly Urticaria Activity Score (UAS7) showed significant improvements in daily itch and hive scores among patients who received barzolvolimab. Complete response rates were also higher than those in the placebo group at both weeks 12 and 24.

The effect was particularly pronounced among patients who did not respond to Xolair (omalizumab), made by Roche subsidiary Genentech and Novartis. In the 150-mg groups, complete response rates at week 12 were 55.3% and 41.7%, respectively, substantially exceeding the placebo groups’ rates of 9.3% and 15.1%. The 300-mg groups recorded rates of 44.3% and 46.4%.

During a conference call on the 22nd, the company said that only two patients experienced anaphylaxis after dosing and that the overall discontinuation rate was 16%, primarily because patients withdrew consent.

Celldex plans to continue the trials for 52 weeks and then submit an application for approval to the U.S. Food and Drug Administration (FDA) in 2027.

Anthony Marucci, Celldex co-founder and chief executive officer (CEO), said, "Barzolvolimab is well positioned to address the CSU patient population with significant unmet needs. We will build on our leadership in mast cell biology and establish a commercialization-stage organization to deliver the drug to patients and physicians as quickly as possible."

Meanwhile, barzolvolimab previously failed to meet the primary endpoint in a phase 2 trial for prurigo nodularis, another chronic skin disease, in July. On the same day, Q Biopharma announced that its candidate CUE-221 had met the primary endpoint in a phase 2 CSU trial.