JAMA Dermatol

Investigational BTK inhibitor reduces symptoms in chronic spontaneous urticaria

April 28, 2025

Rilzabrutinib offers a potential new treatment option for chronic spontaneous urticaria (CSU) patients who don’t respond to standard antihistamines, providing rapid and sustained relief from hives and itch.

Study details: The phase 2 Rilzabrutinib Efficacy and Safety in CSU (RILECSU) trial evaluated rilzabrutinib in 160 adults with CSU unresponsive to H1-antihistamines. Participants were randomized to receive placebo or rilzabrutinib at doses of 400 mg, 800 mg, or 1200 mg daily for 12 weeks.

Results: Rilzabrutinib at 1200 mg/day significantly reduced the weekly Urticaria Activity Score (UAS7) and Itch Severity Score (ISS7) compared with placebo at week 12, meeting the primary endpoint. The least squares mean difference in ISS7 was -3.44 (95% confidence interval [CI] -6.25 to -0.62; P = .02) and in UAS7 was -6.75 (95% CI -12.23 to -1.26; P = .02). Adverse events included diarrhea, nausea, and headache, but rilzabrutinib demonstrated a favorable risk-benefit profile.

Source:

Giménez-Arnau A, et al. (2025, April 23). JAMA Dermatol. Rilzabrutinib in Antihistamine-Refractory Chronic Spontaneous Urticaria: The RILECSU Phase 2 Randomized Clinical Trial. https://pubmed.ncbi.nlm.nih.gov/40266575/