Primary -To evaluate the efficacy of itepekimab compared with placebo on NP size and nasal congestion Secondary - To evaluate the long-term efficacy of itepekimab compared with placebo on NP size. - To evaluate the long-term efficacy of itepekimab compared to placebo on nasal congestion. - To evaluate the efficacy of itepekimab compared with placebo on sinus opacification. - To evaluate the efficacy of itepekimab compared to placebo on symptoms of CRSwNP. - To evaluate the efficacy of itepekimab compared to placebo on sense of smell. - To evaluate the efficacy of itepekimab compared to placebo on health-related quality of life. - To evaluate the efficacy of itepekimab compared to placebo on sleep disturbance. - To evaluate the ability of itepekimab compared to placebo to reduce the risk of worsening/acute sinusitis requiring treatment with SCS or sinus surgery. - To evaluate the effect of itepekimab compared to placebo on asthma in the subgroup of participants with comorbid asthma. - To evaluate the effect of itepekimab compared to placebo in the subgroup of participants with AERD. - To evaluate the efficacy of itepekimab compared to placebo. - To evaluate the safety and tolerability of itepekimab compared to placebo in participants with CRSwNP. - To evaluate the PK of itepekimab. - Assessment of immunogenicity to itepekimab over time compared to placebo.