An Open-label Extension Study to Evaluate the Long-term Safety and Tolerability of LOU064 in Subjects With CSU

This was an open-label, single-arm, multicenter, long-term safety and tolerability extension study for CSU patients rolling over from study CLOU064A2201 (NCT03926611). Subjects rolling over from CLOU064A2201 with a weekly Urticaria Activity Score (UAS7)\<16 after the follow-up period at Week 16 were further followed up without receiving LOU064 for up to 12 weeks (observational period). If there was a relapse (UAS7≥16 at least once), the 12-week observational period was terminated, and subjects entered the treatment period. Subjects who never relapsed within 12 weeks completed the study after the observational period without treatment. Subjects who rolled over from CLOU064A2201 with a UAS7≥16 at Week 12 or Week 16, as well as those subjects who relapsed during the 12-week observational period, were treated with 100 mg LOU064 twice a day (b.i.d.) open-label for 52 weeks. No background medication with a second-generation H1-antihistamine was permitted up to Week 4 of the treatment period. Subjects who completed the treatment period or who discontinued treatment early were followed-up for a minimum duration of 4 weeks. Subjects who had a UAS7≤6 at Week 52 of the treatment period had their follow-up period extended until relapse (UAS7≥16) for up to a total of 16 weeks.