In a phase 3 clinical trial (NCT01892345) treatment with eculizumab (Soliris; Alexion, New Haven, CT) significantly reduced relapse rates for persons with neuromyelitis optica spectrum disorder (NMOSD). Treatment with eculizumab reduced risk by 94% compared with placebo (HR, 0.058 [95% CI: 0.017-0.197]). After 48 weeks of treatment, 2.1% of participants treated with eculizumab had a relapse compared with 36.8% of patients treated with placebo. The annualized relapse rate (ARR) for individuals treated with eculizumab was .016 compared with .35% for those treated with placebo (P < .0001).
In this study, 143 participants were randomly assigned to receive treatment with eculizumab or placebo, and 124 individuals completed the trial, which ended after 20 persons in the placebo arm and 3 in the treatment arm had experienced a relapse. Participants were primarily women (90.9%) and a median age of 45. Baseline ARR for those in the treatment arm was 1.94 ± 0.896 and 2.07 ± 1.037 for those in the placebo arm and use of supportive immunosuppressive therapy were similar in the 2 groups (78.1% for treatment group, 72.3% for placebo group). Relapse recurrence was determined to have occurred (adjudicated) by an independent blinded expert panel.
For eculizumab and placebo groups, Treatment-emergent adverse event rates were 1,160.9 for individuals treated with placebo and 749.3 for those treated with eculizumab. Most treatment-adverse events were mild to moderate. In the eculizumab treatment arm, 1 death occurred that was not deemed related to treatment (pleural effusion from encapsulated bacteria). No cases of meningococcal meningitis, a known risk of eculizumab.
Leeann B. Burton, MD, and Amanda C. Guidon, MD
Elizabeth Ackley, MD, and Marcy E. Yonker, MD, FAHS
Lee I. Kubersky, MD