Spacing out biologic treatment doses in chronic rhinosinusitis with nasal polyps

Who can take part

• ≥18 years of age
• Currently receiving treatment with either dupilumab (300 mg) or mepolizumab (100 mg) every four weeks
• Having received the biologic at unchanged dosing interval for at least three months
• For at least one year during treatment with biologics, the patients' CRSwNP must be categorized as "partly controlled" as defined by presence of 1-2 of the following seven items (also available in EPOS 2020 table in protocol):; Nasal blockage: present on most days of the week; Rhinorrhoea/postnasal drip: mucopurulent on most days of the week; Facial pain/pressure: present on most days of the week; Sense of smell: impaired; Sleep disturbance or fatigue: present; Nasal endoscopy: diseased mucosa; Rescue treatment (systemic corticosteroids, ESS, antibiotics): need of 1 course of rescue treatment; of which 1-5 will be scored by the patient using VAS (0-10) and noted above 5

Who cannot take part

• Patients with excellent response to biologics (0 of the above-mentioned 7 items for partly controlled disease)
• Patients with no or limited response to biologics (>2 of the above-mentioned 7 items for partly controlled disease)
• Patients with a cancer diagnosis deemed by the investigator to preclude participation in the trial
• Patients who currently receive biologics for any other disease (asthma not included)
• Patients who, because of language barriers, are not able to understand Danish written information and, thus, are not able to answer questionnaires
• Patients who are not able to give informed consent (i.e., patients who are permanently incapable)
• Patients who are not eligible because of the investigator's judgement
• Patients who experience pregnancy during the study will be excluded after an unscheduled visit - active IVF treatment (please see below)
• Unwillingness to follow the study procedure