Response to mepolizumab according to disease manifestations in patients with eosinophilic granulomatosis with polyangiitis.

BACKGROUND: Eosinophilic granulomatosis with polyangiitis (EGPA) is a relapsing disease with frequent glucocorticoid dependence. Mepolizumab has been demonstrated to reduce flares and spare glucocorticoids (GC). However, EGPA is a heterogeneous condition and the effects of mepolizumab on specific disease manifestations has not been completely delimitated. OBJECTIVES: To analyse the impact of mepolizumab on manifestations derived from small-vessel vasculitis, ENT (ear, nose and throat) symptoms, asthma, eosinophilic tissue infiltration and anti-neutrophil cytoplasmic antibody (ANCA) status in a single-centre cohort of EGPA patients. METHODS: Medical charts of EGPA patients treated with mepolizumab were retrospectively reviewed by the authors to describe demographics, clinical characteristics, steroid dose at the initiation of mepolizumab and during follow-up, flares, disease activity, damage accrual and laboratory results. RESULTS AND CONCLUSIONS: Among 56 patients with EGPA regularly controlled at our department, 11 patients were treated with mepolizumab because of corticodependence and unsatisfactory disease control. The mean time of treatment was 38 months (range: 3-66 months). Patients with persistent symptoms improved their asthma control, but 3 of them persisted with recurrent ENT symptoms in spite of treatment with mepolizumab. None of the patients developed vasculitic manifestations (cutaneous, neurological, gastrointestinal, renal) during treatment. All patients achieved a Birmingham Vasculitis Activity Score (BVAS) of 0 points at 12 months or earlier. In general, patients reduced the number of flares, which tended to be milder, and all related to asthma or ENT manifestations. The improvement in disease activity allowed notable glucocorticoid tapering.