Mepolizumab add-on after relapse during rituximab maintenance in MPO-ANCA-positive eosinophilic granulomatosis with polyangiitis: a case report and literature review

Abstract

Eosinophilic granulomatosis with polyangiitis is a heterogeneous vasculitic and eosinophilic disorder in which patients who are positive for myeloperoxidase antineutrophil cytoplasmic antibody often develop glomerulonephritis and peripheral neuropathy and may require prolonged immunosuppressive therapy. Although rituximab and mepolizumab have been used in selected patients with EGPA, relapse during rituximab maintenance remains difficult to manage. We report a 59-year-old woman with adult-onset asthma and chronic rhinosinusitis who presented with severe eosinophilia, mononeuritis multiplex, myeloperoxidase anti-neutrophil cytoplasmic antibody positivity, and pauci-immune necrotising glomerulonephritis. Induction therapy with high-dose glucocorticoids, intravenous immunoglobulin, and rituximab achieved clinical remission and allowed tapering to a low dose of prednisolone. Despite rituximab maintenance, she later relapsed with recurrent sinonasal symptoms, worsening neuropathic complaints, and a marked rise in myeloperoxidase antineutrophil cytoplasmic antibody levels. In this setting, further escalation of immunosuppression during maintenance, including cyclophosphamide, may be considered; however, given the possibility that residual eosinophilic inflammation contributed to ongoing disease activity, including autoantibody production, mepolizumab was added after retreatment with rituximab as sequential therapy. Symptoms stabilised and improved over subsequent months, myeloperoxidase antineutrophil cytoplasmic antibody titres progressively declined to the normal range, and prednisolone was discontinued. Remission has been maintained on mepolizumab without further rituximab for maintenance. This case suggests that sequential eosinophil-targeted therapy may help consolidate remission after relapse during rituximab maintenance in myeloperoxidase antineutrophil cytoplasmic antibody–positive eosinophilic granulomatosis with polyangiitis.