To evaluate rates of relapse-related hospitalization and associated treatment for eculizumab in aquaporin-4 immunoglobulin G (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD) in the PREVENT study.

Relapses resulting in hospitalization are common in patients with the rare autoimmune inflammatory disease NMOSD. The randomized, double-blind, placebo-controlled PREVENT study assessed the safety and efficacy of eculizumab in AQP4-IgG-positive NMOSD (NCT01892345). Eculizumab significantly reduced the risk of adjudicated relapse compared with placebo (primary endpoint).

Patients with AQP4-IgG-positive NMOSD were randomized 2:1 to receive eculizumab (maintenance dose, 1200 mg/2 weeks, n = 96) or placebo (n = 47) with/without stable-dose concomitant immunosuppressant therapy (excluding rituximab and mitoxantrone). Hospitalizations were recorded as a component of the adverse event tracking performed throughout the study. The annualized relapse-related hospitalization and treatment rates were defined as the total number of relapses requiring hospitalization, or treatment divided by the total number of patient-years in the study period.

The median exposure to treatment was 89.43 weeks for eculizumab and 41.29 weeks for placebo. The overall annualized hospitalization rate was 0.26 and 0.78 (p < 0.0001) in the eculizumab and placebo groups, respectively. The annualized relapse-related hospitalization rate was lower in the eculizumab than in the placebo group: 0.04 versus 0.31, respectively, p < 0.0001. The annualized relapse-related use of intravenous methylprednisolone, plasma exchange and high-dose oral corticosteroids for eculizumab and placebo was 0.07 and 0.42 (p < 0.0001), 0.02 and 0.19 (p = 0.0001) and 0.04 and 0.11 (p = 0.0733), respectively.

Treatment with eculizumab reduced relapse-related hospitalizations and their associated treatment rates in patients with AQP4-IgG-positive NMOSD versus placebo, which may have a favorable effect on health resource utilization.