This is a Phase 3, parallel group, placebo-controlled, double-blind, confirmatory study in patients with CINDU, with an optional Open-label Extension (OLE). The purpose of the core period (52 weeks of treatment) of this study is to evaluate the efficacy, safety, and tolerability of remibrutinib (LOU064) vs. placebo in adults suffering from CINDU inadequately controlled by H1-antihistamines (H1-AHs). The purpose of the OLE period is to collect long-term efficacy, safety, and tolerability data on remibrutinib in participants after having completed the Core period