Trial of Satralizumab in Neuromyelitis Optica Spectrum Disorder

Abstract

BackgroundNeuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system and is associated with autoantibodies to anti–aquaporin-4 (AQP4-IgG) in approximately two thirds of patients. Interleukin-6 is involved in the pathogenesis of the disorder. Satralizumab is a humanized monoclonal antibody targeting the interleukin-6 receptor. The efficacy of satralizumab added to immunosuppressant treatment in patients with NMOSD is unclear.MethodsIn a phase 3, randomized, double-blind, placebo-controlled trial, we randomly assigned, in a 1:1 ratio, patients with NMOSD who were seropositive or seronegative for AQP4-IgG to receive either satralizumab, at a dose of 120 mg, or placebo, administered subcutaneously at weeks 0, 2, and 4 and every 4 weeks thereafter, added to stable immunosuppressant treatment. The primary end point was the first protocol-defined relapse in a time-to-event analysis. Key secondary end points were the change from baseline to week 24 in the visual-analogue scale (VAS) pain score (range, 0 to 100, with higher scores indicating more pain) and the Functional Assessment of Chronic Illness Therapy–Fatigue (FACIT-F) score (range, 0 to 52, with lower scores indicating more fatigue). Safety was also assessed.ResultsA total of 83 patients were enrolled, with 41 assigned to the satralizumab group and 42 to the placebo group. The median treatment duration with satralizumab in the double-blind period was 107.4 weeks. Relapse occurred in 8 patients (20%) receiving satralizumab and in 18 (43%) receiving placebo (hazard ratio, 0.38; 95% confidence interval [CI], 0.16 to 0.88). Multiple imputation for censored data resulted in hazard ratios ranging from 0.34 to 0.44 (with corresponding P values of 0.01 to 0.04). Among 55 AQP4-IgG–seropositive patients, relapse occurred in 11% of those in the satralizumab group and in 43% of those in the placebo group (hazard ratio, 0.21; 95% CI, 0.06 to 0.75); among 28 AQP4-IgG–seronegative patients, relapse occurred in 36% and 43%, respectively (hazard ratio, 0.66; 95% CI, 0.20 to 2.24). The between-group difference in the change in the mean VAS pain score was 4.08 (95% CI, −8.44 to 16.61); the between-group difference in the change in the mean FACIT-F score was −3.10 (95% CI, −8.38 to 2.18). The rates of serious adverse events and infections did not differ between groups.ConclusionsAmong patients with NMOSD, satralizumab added to immunosuppressant treatment led to a lower risk of relapse than placebo but did not differ from placebo in its effect on pain or fatigue. (Funded by Chugai Pharmaceutical; ClinicalTrials.gov number, NCT02028884.)