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.
Michelle L. Dougherty, MD, FAES, FAAN
Marwa Kaisey, MD, and Nancy L. Sicotte MD, FAAN
Brad Klein, MD, MBA, FAAN, FAHS, FAANEM, and Raissa Villanueva MD, MPH, FAAN