Ab1265 Analysis of Clinical Outcomes in Eosinophilic Granulomatosis With Polyangiitis (Egpa) Treated With Mepolizumab Over 2 Years for Remission Induction or Maintenance: A Single Center Experience in Japan

Background: Contrary to Western countries, MPO-ANCA-associated vasculitis (MPO-AAV) is dominant in Japan or Asian countries. It is possible that therapeutic responses to EGPA with mepolizumab (MEP) are different in Asian countries. In addition, there have been few reports on the course of long-term treatment of EGPA with MEP. Objectives: To clarify administering MEP from early stage of EGPA affects reducing GC dose, we conducted a retrospective analysis of the clinical database of the 25 patients of EGPA treated with MEP in our hospital for remission induction or remission maintenance. Methods: Twenty-five EGPA patients have been treated with MEP and followed for at least two years since 2018 in the department of Nephrology and Rheumatology in Kyorin University Hospital. They were analysed for clinical courses, including dose of administered corticosteroids (GC) and rates of flare-up. Remission was defined as Birmingham Vasculitis Activity Score (BVAS) was 0. Disease flare-up was defined as a state the disease activity increased and required intensification of immunosuppressive therapy. They were divided into patients who were administered MEP within 3 months of onset (early administration group) and who were started administration of MEP during maintenance therapy at least 3 months after onset (during maintenance group). Results: Of the 25 patients administered MEP, 6 patients were categorized as the early administration group and the other 19 patients were categorized as the during maintenance group. In addition to GC and MEP, cyclophosphamide (CY) was used in 17% (1/6) of the early group and in 53% (10/19) of the maintenance group. After two years of therapy, mean doses of GC of each group were 1.7±2.1mg/day and 3.6±2.7mg/day, respectively. The achievement rates of GC dose below 5mg/day after two years treatment of the early group and the maintenance group were 100% and 47% (9/19), respectively. While no flare-up was observed in the early group, 26% (5/19) of the maintenance group developed flare-up after the start of MEP therapy. These results were similar regardless of ANCA positivity. The incidence of serious infections requiring hospitalization and death after starting MEP were 0 in both groups. Conclusion: These results showed that long-term use of MEP was effective and had an acceptable safety profile in EGPA patients. The use of MEP from early stage might be recommended because the start of MEP within 3 months of onset might reduce the dose of GCs after two years of therapy and the flare-up rate. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: Yoshinori Komagata GSK, Kissei, Eisai, Soko Kawashima: None declared, Riyo Yokota: None declared, Tomoya Hibino: None declared, Yuka Date: None declared, Koichi Usui: None declared, Jin Yamamoto: None declared, Nobuhiro Ayuzawa: None declared, Noriko Ikegaya: None declared, Takahisa Kawakami: None declared, Mitsumasa Kishimoto: None declared, Shinya Kaname: None declared.