Characteristics and Disease Burden of Patients With Eosinophilic Granulomatosis With Polyangiitis Initiating Mepolizumab in the United States

BACKGROUND/OBJECTIVE: Although the high disease burden associated with eosinophilic granulomatosis with polyangiitis (EGPA) has been established, the disease burden in patients initiating mepolizumab in real-world practice is poorly understood. This study aimed to assess characteristics and burden of real-world patients with EGPA initiating mepolizumab. METHODS: This was a database study (GSK study ID: 214156) of US patients (≥12 years old) with EGPA and ≥1 mepolizumab claim (index date) identified from the Merative MarketScan Commercial and Medicare Supplemental Databases (November 1, 2015, to March 31, 2020). Outcomes assessed in the 12-month baseline period before index (inclusive) included patient characteristics, treatment use, EGPA relapses, asthma exacerbations, health care resource utilization, and costs. RESULTS: In the 103 patients included (mean age, 51.1 years; 63.1% female), the most common manifestations were asthma (89.3%), chronic sinusitis (57.3%), and allergic rhinitis (43.7%). In total, 91.3% of patients had ≥1 oral corticosteroid (OCS) claim (median dose, 7.4 mg/d prednisone-equivalent), 45.6% were chronic OCS users (≥10 mg/d during the 90 days preindex), 99.0% had ≥1 EGPA-related relapse, and 62.1% ≥1 asthma exacerbation. During the baseline period, 26.2% and 97.1% of patients had EGPA-related inpatient admissions and office visits, respectively. Median all-cause total health care costs per patient were $33,298, with total outpatient costs ($16,452) representing the largest driver. CONCLUSIONS: Before initiating mepolizumab, a substantial real-world EGPA disease burden is evident for patients, with resulting impact on health care systems, and indicative of unmet medical needs. Mepolizumab treatment, with a demonstrated positive clinical benefit-risk profile may represent a useful treatment option for reducing EGPA disease burden.