Adverse events of mepolizumab in the treatment of nasal polyps: A FDA database evaluation

Background: Mepolizumab has shown significant efficacy in managing eosinophil-associated disorders such as eosinophilic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP). Despite the advancements in treatment options for CRSwNP, traditional therapies often fail to prevent polyp recurrence and come with substantial side effects, emphasizing the need for ongoing evaluation of new therapeutic approaches and their safety profiles. Objectives: Utilize the FDA Adverse Event Reporting System to identify and evaluate adverse effects related to the use of mepolizumab in treating CRSwNP. Methods: From Q12021 until Q12023, the FDA Adverse Event Reporting System database was queried to identify mepolizumab adverse reactions (MARs), which were compared between the two treatment groups of interest, CRSwNP and asthma. Individual MARs (iMARs) were modeled using zero-truncated Poisson regression, while serious MARs and outcomes were modeled using logistic regression. Results: For the CRSwNP-tx group, there were 80 MARs (16 serious MARs, 19 serious outcomes, 0 deaths). For the asthma-tx group, there were 4779 MARs (4308 serious MARs, 2334 serious outcomes, 124 deaths). 68,479 iMARs were observed, with 1198 iMARS in the CRSwNP-tx group. Common CRSwNP-tx iMARs were pulmonary (27.1 %), generalized (10.9 %), neurologic (9.9 %), and hematologic (9.0 %). Age < 50, RR 1.63 [1.41, 1.90], and asthma, RR 5.73 [4.29, 7.66], were significant predictive factors for total iMAR, while sex, RR 1.00 [0.86, 1.16], was not. Within the CRSwNP-tx group, concurrent asthma treatment increased the odds of having a serious MAR by 11.77 [3.02, 53.74] and serious outcome by 26.58 [3.23, 605.81]. Conclusion: Mepolizumab treatment of CRSwNP is associated with fewer individual adverse reactions. Pulmonary reactions were, by far, the most common type of adverse reaction. Concurrent asthma treatment in CRSwNP-only-tx increases the number of reactions, and the seriousness of reactions and outcomes.