Efficacy of Rituximab on Refractory Organ Involvements in Granulomatosis with Polyangiitis: A Systematic Review of Case Reports.

Introduction: Granulomatosis with polyangiitis (GPA) is a type of Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) characterized by necrotizing vasculitis affecting small and medium-sized blood vessels. GPA affects various organs, with respiratory tract, vasculitis and glomerulonephritis being the most common triad. Remission induction and maintenance therapy for GPA traditionally involves corticosteroids and cyclophosphamide. However, treatment with rituximab, a monoclonal antibody that depletes B-cells involved in autoimmune disease, has been successful in inducing remission in several studies. The purpose of this systematic review was to investigate the efficacy of rituximab in treating various clinical manifestations of GPA.

Methods: In adherence to PRISMA guidelines for systematic reviews and meta-analyses, we carried out a comprehensive review to investigate the effectiveness of rituximab on particular organ involvement in GPA. We searched three databases (PubMed, Scopus, and Embase) up until November 6, 2022, for case reports on the topic. To ensure all relevant studies were included, we manually screened the first 50 pages of Google Scholar's search results.

Results: The review identified a total of 64 case reports and a case series of 113 cases, highlighting the effectiveness of rituximab in treating refractory organ involvement in GPA. The review also analyzed the effectiveness of rituximab in treating ocular, CNS, cardiac, pulmonary, cutaneous, gastrointestinal, renal, and other organ involvements in GPA.

Conclusions: Our results indicated that rituximab can be a promising therapy for treating specific clinical manifestations of several organ involvements. However, more research is needed to determine the long-term efficacy of rituximab in treating GPA.