A key goal of treatment for EGPA is to induce and maintain remission while reducing the use of corticosteroids and other immunosuppressive therapies. The co-primary endpoints for this 52-week study assessed the total duration of remission and the proportion of patients that achieved sustained remission following treatment with mepolizumab compared to treatment with placebo, both on top of standard of care. Remission for these two endpoints was defined by a Birmingham Vasculitis Activity Score (BVAS), a scoring system to assess disease activity, of 0 and corticosteroid dose <4mg/day prednisolone/prednisone. The difference between the two treatment groups was statistically significant for both co-primary endpoints as defined, respectively, by:
- The duration of remission as defined by the proportion of patients achieving at least 24 weeks duration of remission, one of five pre-defined categories of duration, was 19/68 (28%) for mepolizumab and 2/68 (3%) for placebo (P<0.001).
- The proportion of patients achieving remission at both weeks 36 and 48 of the study treatment period. This was 22/68 (32%) for mepolizumab and 2/68 (3%) for placebo (P<0.001).
