Background: Eosinophilic granulomatosis with polyangiitis (EGPA) is a relapsing disease with frequent glucocorticoid (GC) dependence. Mepolizumab (MEPO) has been demonstrated to reduce flares and spare GC. However, EGPA is a heterogeneous disease and the effects of MEPO on specific disease manifestations has not been completely delimitated.

Objectives: To analyze the impact of MEPO on manifestations derived from small-vessel vasculitis, ENT symptoms, asthma, eosinophilic tissue infiltration and ANCA status in a single-centre cohort of EGPA patients.

Methods: Medical chart of EGPA patients treated with MEPO were reviewed to describe demographics, clinical characteristics, steroid dose at the initiation of MEPO and during follow-up, flares, disease activity, damage accrual and laboratory results.

Results: Among 52 EGPA patients regularly controlled in our department, 11 patients were treated with MEPO. MEPO was prescribed when a) patients required prednisone (PDN) at ≥ 7.5 mg/d to maintain stability, or b) when maintained with < 7.5mg/d, presented at least 4 exacerbations/year requiring an increase in PDN dose. 6 were males and 5 females, with a mean age of 54 years at MEPO initiation. Baseline characteristics of the patients and course under treatment are presented in Table 1 . ENT involvement, followed by asthma and eosinophil-related tissue-infiltration (ETI) were the most common symptoms when prescribing MEPO. Regarding treatment, patients received MEPO at 100-300mg SC monthly. The definition of flare was the same used in the MIRRA trial ¹ . The mean time of treatment with MEPO was 34 months. All patients achieved a BVAS score 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. All improved their asthma control, but 3 of them persisted with recurrent ENT symptoms in spite of treatment with MEPO. None of them had vasculitic manifestations (cutaneous, neurological, gastrointestinal, renal) manifestations during treatment. All patients were able to tapper their PDN dose to ≤5 mg/day or less, except 3 patients. Of the 3 patients who required ≥5mg/d, 1 had severe asthma, but diminished the previous PDN dose (22.5 mg/d pre-MEPO, 10 mg/d currently) and the yearly rate of flares (8.2 pre-MEPO, 0.64 under-MEPO). The other one notably improved his asthma, but had ENT symptoms that responded unsatisfactorily to MEPO and required a maintenance PDN dose of 7.5 mg/d. The last one, improved her asthma control and was able to begin PDN tapering, but persisted with ENT symptoms. Regarding damage accrual, 6 patients remained stable during treatment, and 5 worsened. Two of three ANCA positive patients remained positive in spite of treatment.

Conclusion: MEPO was effective for the treatment of patients with EGPA, with a reduction in the number and severity of flares and a decrease in PDN doses. A worse response of ENT involvement was observed. No vasculitic flares were observed in spite of GC reduction. Mepolizumab did not prevent damage accrual during the treatment period.

REFERENCES:

[1]Wechsler ME et al. MEPO or Placebo for Eosinophilic Granulomatosis with Polyangiitis. N Engl J Med. 2017.

Acknowledgements: Funding: Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016 (PI18/00461), co-funded by Instituto de Salud Carlos III (ISCIII) and Fondo Europeo de Desarrollo Regional (FEDER) and by Río Hortega program (ISCIII, CM19/00032).

Disclosure of Interests: Roberto Ríos-Garcés: None declared, Sergio Prieto-González: None declared, José Hernández-Rodríguez: None declared, Maria C. Cid Paid instructor for: GSK and Vifor, Consultant of: GSK, Abbvie and Janssen, Grant/research support from: Kiniksa and Roche, Georgina Espígol-Frigolé Consultant of: Janssen, Grant/research support from: Roche