A RESPONSE to anti

Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) and severe asthma (SA) are 2 frequently coexisting conditions that are, in most cases, associated with eosinophilic inflammation. The concurrence of both diseases has a negative synergistic impact on disease severity and patients' health-related quality of life. Thus, a holistic, collaborative management of these patients is a critical unmet need. Mepolizumab, a systemic anti-IL-5 therapy, has been shown to be effective as an add-on treatment in both SA and CRSwNP, with more literature available on asthma outcomes than on CRSwNP. Objectives: The primary objective of the study is to evaluate the real-world effectiveness of mepolizumab in improving the health-related quality of life of comorbid patients at 12 months using the SNOT-22 questionnaire. Secondary objectives include safety and efficacy outcomes of mepolizumab treatment in the 2 populations, which are expected to have variable severity of the respective comorbid conditions. Methods: RESPONSE is a European real-world prospective cohort study designed to assess the effectiveness of mepolizumab in 2 cohorts of adult patients: one with SA as primary diagnosis with (secondary diagnosis) comorbid CRSwNP, and another with CRSwNP as primary diagnosis with (secondary diagnosis) comorbid asthma. Up to 350 patients receiving newly prescribed mepolizumab will be followed up for 12 months as per the investigators' standard of care. Conclusion: This study will report the effects of anti-IL-5 therapy in both diseases investigated and the respective comorbidity, as well as the consequence of treating milder forms of asthma and CRSwNP with mepolizumab, supporting the emerging evidence on early treatment optimization.