Chronic rhinosinusitis without nasal polyps

Primary objective: To evaluate the efficacy of itepekimab compared with placebo on sinus opacity. Secondary objectives: To evaluate the efficacy of itepekimab compared with placebo on sinus symptoms; To evaluate the efficacy of itepekimab compared with placebo on symptoms of chronic rhinosinusitis without nasal polyps (CRSsNP); To evaluate the efficacy of itepekimab compared with placebo on health-related quality of life (HRQoL); To evaluate the efficacy of itepekimab compared with placebo on other sinus opacity indicators; To evaluate the safety and tolerability of itepekimab compared with placebo in CRSsNP participants; To evaluate the PK of itepekimab. Itepekimab immunogenicity assessment.