Early mepolizumab initiation during remission induction is associated with lower organ damage burden in EGPA: a multicentre cohort study.

OBJECTIVES: To evaluate whether early mepolizumab initiation during remission induction is associated with favourable clinical outcomes and lower organ damage burden in patients with eosinophilic granulomatosis with polyangiitis (EGPA). METHODS: This retrospective multicentre cohort study used data from Kyushu Vasculitis Cohort Study. Patients with EGPA were classified into an early mepolizumab group, in which mepolizumab was initiated within 3 months of remission induction, and a conventional group. The primary endpoint was clinical remission at 1 year, defined as Birmingham Vasculitis Activity Score (BVAS)=0 with prednisolone ≤4 mg/day. Secondary endpoints included remission at 6 months and 2 years, glucocorticoid exposure, relapse, mortality and organ damage assessed by the Vasculitis Damage Index (VDI). Longitudinal VDI values from 6 months to 2 years were analysed using linear mixed-effects model. RESULTS: Sixty-four patients were included (early mepolizumab, n = 16; conventional, n = 48). Clinical remission at 1 year was achieved more frequently in the early mepolizumab group than in the conventional group (69% vs 27%; P = 0.006). At 2 years, remission was achieved in 10/10 (100%) versus 13/45 (29%) evaluable patients (P < 0.001), and glucocorticoid discontinuation in 4/10 (40%) versus 4/45 (9%) (P = 0.029). BVAS decreased markedly in both groups. Early mepolizumab initiation was associated with lower longitudinal VDI values (β = -0.36, 95% CI - 0.70 to - 0.03; P = 0.032). CONCLUSION: Early mepolizumab initiation was associated with higher remission rates, lower glucocorticoid exposure and lower organ damage burden during the first 2 years in EGPA.