Efficacy of different rituximab therapeutic strategies in patients with neuromyelitis optica spectrum disorders

Objective: To evaluate disease activity according to rituximab (RTX) induction and maintenance regimens in a multicenter real-life dataset of NMOSD patients. Methods: This is an observational-retrospective multicentre study including patients with NMOSD treated with RTX in 21 Italian and 1 Swiss centers. Demographics, relapse rate and adverse events over the follow-up were summarized taking into account induction strategy (two-1 g infusions at a 15-day interval (IND-A) vs. 375 mg/m2/week infusions for one month (IND-B)) and maintenance therapy (regimen A (M-A) with fixed time-points infusions vs. regimen B (M-B) based on cytofluorimetric driven reinfusion regimens, the least further subdivided according to CD19 + B cells (M-B1) or CD27 + memory B cells (M-B2) monitoring). Results: 131 subjects were enrolled, 127 patients completed the induction regimen and 119 patients had at least one follow-up visit and were included in the outcome analysis. Median follow-up was 1.7 years (range 0.1-11.6). Annualized relapse rate (ARR) was 1.7 in the year before RTX start and decreased to 0.19 during the follow-up. Both ARR and Time to first relapse ( raR) analysis showed a trend toward an increased disease activity for IND-B and M-A. No patients with MT-B2 experienced relapses during the follow-up. Number of relapses in the year before RTX initiation and having received a previous treatment were significantly associated with higher ARR and reduced TTFR in the multivariate analysis. Interpretation: We confirm RTX efficacy in NMOSD patients. Use of specific induction and maintenance protocols is warranted in order to foster RTX efficacy and to reduce costs and side effects.