Trends in prevalence, treatment use, and disease burden in patients with eosinophilic granulomatosis with polyangiitis in Japan: Real-world database analysis

Objectives: We report the prevalence of eosinophilic granulomatosis with polyangiitis (EGPA) and describe oral corticosteroid (OCS) use and disease burden before and after the mepolizumab approval in 2018 for EGPA in Japan.Methods: Two retrospective studies (GSK IDs: 218083 and 218084) used two databases: (1) the JMDC insurer database (Japanese health insurer claims) was used to report annual EGPA prevalence and OCS use in mepolizumab-treated patients and (2) Medical Data Vision database was used to report annual treatment use, OCS dose, relapses, and healthcare resource utilization in patients with EGPA.Results: EGPA prevalence (95% confidence interval) increased from 4.2 (0.1, 23.4) in 2005 to 58.6 (53.2, 64.5) per 1,000,000 in 2020. Median OCS dose (mg/day) decreased from a range of 4.8-7.7 during 2010-2017 to 4.5-4.8 during 2018-2020 (lowest dose in 2020). The proportion of patients with prednisolone-equivalent daily OCS dose >10 mg decreased from 2017 (11.9%) to 2020 (10.3%), while the median dose halved. The proportion of patients with EGPA relapses (64.3% to 41.6%) and hospitalization (27.8% to 23.6%) decreased from 2010 to 2020.Conclusions: EGPA prevalence increased between 2005 and 2020. With the introduction of mepolizumab for EGPA in 2018, real-world OCS use, relapses, and healthcare resource utilization decreased.