Effectiveness and Safety of Avacopan as a Combination Therapy with Glucocorticoids or Monotherapy in Patients with Microscopic Polyangiitis.

We herein report three cases of microscopic polyangiitis (MPA). Two patients were administered avacopan in combination with glucocorticoid (GC), whereas one patient was treated with avacopan monotherapy; none of the patients were co-administered either rituximab or cyclophosphamide. The doses of GC were successfully reduced after the introduction of avacopan in the two patients, and the serum C-reactive protein levels decreased in the patient treated with avacopan monotherapy. Avacopan may therefore be effective either in combination with GC or as monotherapy, even for patients at a high risk of developing adverse effects when administered rituximab or cyclophosphamide.