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

OBJECTIVES: Report the prevalence of eosinophilic granulomatosis with polyangiitis (EGPA) and describe oral corticosteroid (OCS) use and disease burden before and after mepolizumab approval in 2018 for EGPA in Japan. METHODS: Two retrospective studies (GSK IDs: 218083; 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; 2) Medical Data Vision database was used to report annual treatment use, OCS dose, relapses, and healthcare resource utilization (HCRU) 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 hospitalisation (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 HCRU decreased.