Effectiveness of satralizumab in a real-world clinical setting in Japan: Interleukin-6 receptor inhibition in neuromyelitis optica spectrum disorder: A six-month interim analysis of a multicenter medical chart review

Background: Satralizumab is approved in Japan for relapse prevention of neuromyelitis optica spectrum disorder (NMOSD) in aquaporin-4 immunoglobulin G–seropositive (AQP4[+]) patients. However, clinical trial data for Japanese patients are limited. Methods: SAkuraBeyond, an ongoing real-world observational study (UMIN000050027), evaluates NMOSD relapse over 2.5 years among satralizumab-treated patients with AQP4[+] NMOSD in Japan (25 sites). Herein, we present a 26-week interim effectiveness analysis. Patient data were derived from medical chart review and electronic case report forms. Results: Of the 125 enrolled patients who initiated satralizumab, 124 were included in the study (mean age, 51.1 years; female, 93.5 %; mean disease duration, 7.0 years). At week 26, 120 patients were relapse-free (12 withdrew from satralizumab). The annualized relapse rate [95 % confidence interval (CI)] was 0.069 [0.026–0.183] at week 26 after satralizumab initiation and 0.445 [0.342–0.580] within 52 weeks before satralizumab initiation. The relapse-free rate [95 % CI] at week 26 was 96.6 % [91.2–98.7]. Four patients had relapses, of whom 1 discontinued satralizumab. Three recorded a modified Rankin Scale of ≤3 (1 with unknown status). The mean oral glucocorticoid (GC) dose reduced from baseline to 26 weeks of satralizumab treatment; the GC dose was reduced in 71.3 % of patients treated with oral GC >0 mg at baseline. Azathioprine and tacrolimus doses could be reduced to 0 mg/day in 35.3 % and 26.2 % of relapse-free patients, respectively, at week 26. Conclusion: The 6-month relapse-free rate after satralizumab treatment was 96.6 %. Satralizumab use permitted dose reduction of concomitant oral GC and immunosuppressants over 26-weeks.