Remibrutinib provides fast and clinically important improvement of chronic spontaneous urticaria disease activity

IntroductionThe weekly Urticaria Activity Score (UAS7 range 0–42) is used to evaluate treatment response in chronic spontaneous urticaria (CSU) patients. A decrease in UAS7 of 9.5–10.5 points is considered the minimum important difference (MID) to indicate a meaningful clinical response to therapy. We explored the onset of action of remibrutinib in terms of early achievement of MID-UAS7 of 10.5 points.MethodsThis post hoc analysis of Phase 2b study (NCT03926611) evaluated data of 309 CSU patients from the full analysis set (of 311 patients) who were equally randomized to remibrutinib 10/35/100 mg q.d., 10/25/100 mg b.i.d., or placebo for 12 weeks. The proportion of patients achieving MID-UAS7 at any time (Weeks 0–12) and early (Weeks 0–2); the median time to achieve complete response (UAS7=0) and well-controlled disease (UAS7≤6) in patients who had achieved MID-UAS7 early were analyzed.ResultsIn patients with MID-UAS7 achieved in the first week after randomization, the mean baseline UAS7 across remibrutinib doses was 28.0–33.2 (placebo: 32.3). A higher proportion of patients on remibrutinib versus placebo achieved MID-UAS7 at any time (77.8%–93.2% vs 59.5%), with more patients achieving MID-UAS7 in the first two weeks (64.4%–83.7% vs 23.8%). Of these early MID-UAS7 achievers, the median time to achieve UAS7=0 and UAS7≤6 was shorter for all remibrutinib arms versus placebo.ConclusionIn this post hoc analysis, the majority of patients achieved MID-UAS7 during the first 2 weeks of remibrutinib treatment, thus indicating a fast onset of action of remibrutinib.