Relapse Rates in Patients with GPA or MPA on Rituximab (RTX) Maintenance Therapy: A Single-Center Experience Observational Study from Saudi Arabia

Abstract

Introduction: ANCA-associated vasculitis (AAV) is a rare, systematic, small-vessel inflammatory disorder, leading to conditions such as granulomatosis with polyangiitis (GPA), and microscopic polyangiitis (MPA). While glucocorticoids and immunosuppressants are effective in inducing remission, maintaining it remains a challenge. Rituximab (RTX) has become the preferred choice for maintenance therapy.

Objective: To evaluate the effectiveness of rituximab in maintaining remission by analyzing relapse rates among patients with GPA or MPA while receiving RTX.

Methods: An ambispective cohort study was conducted at King Fahad Medical City between 2015 and 2025 which included patients (>14 years old) diagnosed with GPA or MPA. Descriptive statistics were used, and relapse-free survival was estimated using Kaplan–Meier model. The French Vasculitis Study Group Relapse Score (FRS) was incorporated into the study, which includes three variables and a score that ranges from 0 to 3 points: positivity of PR3-ANCA, GFR ≥30 mL/min/1.73 m², and age ≤75 years.

Results: A total of 33 patients were included in the analysis; 81.7% had GPA. Ear, nose, and throat involvement was in 72.7% of patients. At 36 months, relapse-free survival was 76.6%. Six patients (18.2%) experienced relapses. The median steroid dose did not differ between patients with or without relapses. Patients with an FRS score of 1-2 had much higher relapse-free survival, but this was not statistically significant (log-rank test p-value = 0.3).

Conclusion: Rituximab appears to be an effective maintenance therapy for AAV in this Saudi cohort, with relatively low relapse rates and sustained remission in most patients.