Usage status of biologics for the chronic treatment of optic neuritis in neuromyelitis optica spectrum disorders in Japan

Purpose To investigate the usage status of biologics for the chronic treatment of optic neuritis including neuromyelitis optica spectrum disorders in Japan. Design Multicenter retrospective case series. Methods Patients diagnosed with anti-aquaporin 4 antibody (AQP4-Ab) positive optic neuritis and had been initiated on biologics (satralizumab, eculizumab, and inebilizumab) between January 2020 and August 2022 were identified at 30 facilities in Japan. These patients were investigated regarding changes in oral steroid doses, optic neuritis relapse, and adverse events after initiation of biologics. Results Eighty-eight patients with AQP4-Ab positive optic neuritis initiated on biologics were included. Satralizumab was the most common biologic used (79 patients), followed by eculizumab (6 patients) and inebilizumab (3 patients). In the satralizumab group, during the observation period (10.0 +/- 7.0 months) until February 2023, the oral steroid dose was reduced significantly from 13.8 +/- 8.6 mg/day at the time of initiation to 5.3 +/- 4.8 mg/day (p < 0.001). No relapse of optic neuritis was observed in 76 of 79 patients (96.2%) after initiation of satralizumab. Furthermore, in 15 patients who succeeded in discontinuing steroids during 8.5 +/- 5.8 months after initiation of satralizumab, no relapse of optic neuritis was observed throughout the observation period. Adverse events occurred in 7 patients with satralizumab and 2 patients with eculizumab, but no serious infections were observed. Conclusions Satralizumab was the most commonly used biologic for AQP4-Ab positive optic neuritis in Japan. This study demonstrates the efficacy and safety of satralizumab in preventing the relapse of optic neuritis.