Background/Purpose: EGPA is a multisystem disorder often characterized clinically by asthma, chronic rhinosinusitis, and prominent eosinophilia, and histopathologically by eosinophil-rich, necrotizing , granulomatous vasculitis of small to medium-sized arteries. The U.S. Food and Drug Administration (FDA) approved mepolizumab (Nucala) treatment for adult patients with EGPA in 2017. The burden of illness among EGPA patients who undergo treatment with mepolizumab in real-world practice is poorly understood. This study describes the baseline demographic and clinical characteristics of a real-world population who were initiated on mepolizumab for EGPA.

Methods: This retrospective study identified 103 EGPA patients with at least one mepolizumab claim between November 1, 2015, and March 31, 2020, and at least 12 months continuous enrollment during the 1 year prior to the initiation of mepolizumab (baseline period) using MarketScan Commercial and Medicare Supplemental databases. Patients were excluded if they had any evidence of mepolizumab, benralizumab, dupilumab, omalizumab, reslizumab or rituximab during the baseline period. Demographic characteristics were measured on the date of initiation of mepolizumab (index date) and clinical characteristics, including comorbid conditions, use of oral corticosteroids, annual rate and frequency of asthma exacerbations and EGPA-related relapse were measured in the baseline period.

Results: Of the 103 EGPA patients initiating mepolizumab who met the study eligibility criteria, majority were female (63.1%), urban (84.5%) and commercially insured (91.3%). The mean age was 51.1 years. The most common baseline comorbidity was asthma (89.3%). A vast majority (91.3%) of EGPA patients had evidence of oral corticosteroid (OCS) use, and more than half (63.1%) had evidence of chronic OCS use defined as ≥5 mg/day during the baseline period. The mean, standard deviation (SD) OCS pharmacy claims per patient was 6.5 (4.4) and the mean (SD) daily dose was 10.0 mg (13.9 mg) prednisone equivalents. 26.2% of the patients had an EGPA-related inpatient admission and 97.1% had an EGPA-related office visit. Despite the treatment during the baseline period and contact with the healthcare system, 62% experienced an asthma exacerbation and the mean (SD) number of exacerbations per patient was 1.5 (1.6). Most (99%) patients experienced at least one EGPA-related relapse.

Conclusion: In a real-world setting, patients with EGPA initiating mepolizumab had a significant disease and healthcare burden as shown by high asthma exacerbation rates, EGPA relapses, OCS use and presence of comorbidities. Our data supports that in routine clinical practice, all EGPA patients undergoing initiation of mepolizumab feature a severe disease profile and considerable unmet need.

Funding: (GSK-funded: ID #214156)Previously presented at CHEST 2022.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/baseline-characteristics-in-patients-with-eosinophilic-granulomatosis-with-polyangiitis-in-the-u-s-initiating-mepolizumab/