To assess safety outcomes in patients who initiated C5IT ≤1 year of rituximab exposure in the PREVENT and CHAMPION-NMOSD studies. 

Rituximab is often prescribed off-label in early lines of therapy for AQP4-Ab+ NMOSD; however, patients frequently transition to other therapies like C5ITs to prevent relapses. Safety outcomes in these patients are important considerations. PREVENT (NCT01892345) and CHAMPION-NMOSD (NCT04201262) were phase 3 studies evaluating safety and efficacy of eculizumab and ravulizumab, respectively, in adults with AQP4-Ab+ NMOSD.

Thirty-eight patients received rituximab within >3 to ≤12 months prior to first C5IT dose; 116 patients did not. In prior-rituximab-treated patients, mean time from last rituximab to first C5IT dose was 6.53 months (SD 1.96). The incidence of patients experiencing TEAEs (94.7% vs 90.5%) and TESAEs (21.2% vs 24.1%) was similar. Most events were mild/moderate in severity and were unrelated to C5IT (investigator assessment). Infections/infestations were the most common TEAE (71.1% vs 71.6%, respectively). In the prior-rituximab-treated group, no deaths occurred; no patients experienced TEAEs/TESAEs leading to C5IT withdrawal. There were no differences in TEAE/TESAE incidence rates when analyzed by time since last rituximab use.

No differences in safety were observed among prior-rituximab-treated patients in the PREVENT and CHAMPION-NMOSD studies. These findings provide important information to guide clinical decision-making when considering a switch from rituximab to C5IT in patients with AQP4-Ab+ NMOSD who received rituximab within the preceding 3–12 months.