Remibrutinib demonstrates favorable safety profile and sustained efficacy in chronic spontaneous urticaria over 52 weeks

Background Remibrutinib (LOU064), an oral, highly selective Bruton's tyrosine kinase inhibitor (BTKi), offers fast disease control in chronic spontaneous urticaria (CSU) patients who remain symptomatic despite second-generation H1-antihistamines. It is currently in phase 3 development for CSU. Objective To evaluate the long-term safety and efficacy of remibrutinib in CSU patients inadequately controlled with H1-antihistamines. Methods In this phase 2b extension study, patients who completed the core study and had a weekly Urticaria Activity Score (UAS7)≥16 at the beginning of the extension study received remibrutinib 100 mg twice daily for 52 weeks. The primary objective was to assess long-term safety and tolerability. Key efficacy endpoints included change from baseline in UAS7 and proportion of patients with complete response to treatment (UAS7=0) and well-controlled disease (UAS7≤6) at week 4 and over 52 weeks. Results Overall, 84.3% (194/230) of patients entered the treatment period and received ≥1dose of remibrutinib. The overall safety profile of remibrutinib was comparable between the extension and core studies. Most treatment-emergent adverse events (TEAEs) were mild-to-moderate and considered unrelated to remibrutinib by investigators. The 3 most common TEAEs by system organ class were infections (30.9%), skin and subcutaneous tissue (26.8%), and gastrointestinal disorders (16.5%). At week 4 and 52, mean±standard deviation change from baseline in UAS7 was −17.6±13.40 and −21.8±10.70; UAS7=0 (as observed) was achieved in 28.2% and 55.8%, and UAS7≤6 (as observed) in 52.7% and 68.0% of patients, respectively. Conclusion Remibrutinib demonstrated a consistent favorable safety profile with fast and sustained efficacy for up to 52 weeks in CSU patients.