• Participants who have completed the treatment period and the follow up period in CRSwNP lunsekimig parent study, including EOS visit, as per protocol. - Participants receiving therapy with intranasal mometasone furoate nasal spray (MFNS). - Participants who are able and willing to participate in this extension study, and to comply with requested study visits and procedures.

Participants are excluded from the study if any of the following criteria apply: - Prior hypersensitivity reaction to lunsekimig or to any of the excipients used in the presentation or in preparation for administration of lunsekimig, or other allergy that, in the opinion of the Investigator, contraindicates participation in the study. - Concurrent participation in any clinical study other than the parent study, including non-interventional studies. - Participants who, during their participation in the parent study, developed an adverse event (AE) or a serious adverse event (SAE) deemed related to lunsekimig, which in the opinion of the Investigator could indicate that continued treatment with lunsekimig may present an unreasonable risk for the participant. NOTE: The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial