Tapering of Biologics in Chronic Rhinosinusitis With Nasal Polyps

Inclusion Criteria: * ≥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): 1. Nasal blockage: present on most days of the week 2. Rhinorrhoea/postnasal drip: mucopurulent on most days of the week 3. Facial pain/pressure: present on most days of the week 4. Sense of smell: impaired 5. Sleep disturbance or fatigue: present 6. Nasal endoscopy: diseased mucosa 7. 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. Exclusion Criteria: * 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, because of language barriers, are not able to understand Danish written information and, thus, are not able to answer questionnaires * Patients who currently receive biologics for any other disease (asthma not included) * 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