P0381THE UTILITY OF LOW DOSE RITUXIMAB FOR INDUCTION AND MAINTENANCE TREATMENT IN ELDERLY PATIENTS WITH ANCA-ASSOCIATED VASCULITIS: A SINGLE CENTRE EXPERIENCE

Abstract

Abstract Background and Aims Elderly patients with Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) tend to have higher rates of mortality and treatment-related adverse events. Rituximab is now widely used in the treatment of patients with AAV based on the results of remission induction (RITUXVAS and RAVE) and remission maintenance (MAINRITSAN) randomized controlled trials. Elderly patients were relatively under-represented in these trials. In this observational study we aimed to examine the outcome of elderly patients who received Rituximab (either as low dose Rituximab (LDR) or standard dose Rituximab (SDR)) for remission induction and maintenance. Method We investigated the outcome of three treatment strategies in elderly (age>65 years) patients who presented with AAV to our Vasculitis clinic from 1 July 2007 to 9 of July 2017. These strategies included: LDR (17 patients), SDR (14 patients) and Cyclophosphamide/Azathioprine (Cyc/A) 26 patients. LDR patients received two dose of 500mg Rituximab fortnightly followed by six monthly 500mg doses for 2 years. SDR patients received 1g Rituximab fortnightly followed by six monthly 1g doses for 2 years. Cyc/A patients received 1.5mg/kg oral Cyclophosphamide for 3 months followed by 18 months of Azathioprine. Results Among 57 AAV patients, 56% were females and mean age of 79.6 +/- 4 (LDR), 72.4 +/- 7.2 (SDR), and 71.1 +/- 5 (Cyc/A) (p=0.001). The distribution of MPA and GPA was 11/6 in LDR, 7/7 in SDR and 18/8 in Cyc, respectively. Relapsing GPA was significantly higher in SDR 12/2 compared to LDR 3/14, and Cyc/A 0/26 (p=0.0001). There were no significant differences in serum creatinine, BVAS scores or CRP between groups at initiation of treatment. Patients survival at 24 months was 88% (LDR), 92% (SDR), and 77% (Cyc), p=0.3. The mean corticosteroids dose at 3 months from onset of treatment was significantly lower in the LDR (7.6 +/- 1.7) and SDR (8.6 +/- 3.1) compared with Cyc/A (12.5 +/- 3.6), p=0.001. 1 patients relapsed in the SDR group and 4 patients in the Cyc/A group. Hospitalization for infections were significantly lower in the LDR (3 episodes) compared to Cyc/A (17 episodes), p=0.004. The number of patients with hypogammaglobulinemia was not significantly different between LDR and SDR. Conclusion In this single centre observational study, we found that low dose Rituximab for remission induction and maintenance associated with similar patient outcome to SDR. The findings of this study needs to be replicated with longer duration of follow-up.