Long-term efficacy and safety results of eculizumab monotherapy in patients with aquaporin-4 IgG-positive (AQP4+) neuromyelitis optica spectrum disorder (NMOSD) during the PREVENT trial and/or its ongoing open-label extension were reported [1]. Over 90% of patients who had experienced 1 or 2 relapses in the pre-study year remained relapse-free through 192 weeks of eculizumab monotherapy.

PREVENT was a randomized, double-blind, phase 3 trial in which eculizumab was associated with a significantly lower risk of relapse than placebo among patients with AQP4+ NMOSD, and was well tolerated [2]. Participants were allowed to enter the study while on a stable maintenance dose of immunosuppressive therapy (IST) for relapse prevention; about a quarter did not use IST. In a prespecified subgroup analysis of PREVENT, the treatment effect of eculizumab without concomitant IST was consistent with the overall population.

The long-term post-hoc efficacy results presented at the MSVirtual2020 centered on the 33 patients who received eculizumab as monotherapy during PREVENT and/or its open-label extension, for a total of 85.3 patient-years (PY; interim data cut-off: July 31, 2019). In PREVENT, 1 of these 33 patients experienced an adjudicated relapse versus 7 of 13 with placebo alone. After 192 weeks, 96.2% of patients who received eculizumab monotherapy and 93.8% of patients who received eculizumab with concomitant IST were relapse-free. Furthermore, no patients receiving eculizumab monotherapy were hospitalized for a relapse or started IST.

Eculizumab has been generally well tolerated in the short- and longer-term in patients who received the drug in the PREVENT study and/or its ongoing open-label extension. The number of adverse events (AEs) after 192 weeks that were related to treatment with eculizumab monotherapy were comparable with placebo in PREVENT: 181.0 versus 186.0 events per 100 PY, respectively. The infection rate was also similar: 174.1 versus 186.0 events per 100 PY. There were no meningococcal infections or deaths. In fact, there were less treatment-related serious AEs with eculizumab monotherapy than with placebo: 5.7 versus 23.3 per 100 PY. The authors concluded that this efficacy and safety update supports the long-term effectiveness and safety of eculizumab monotherapy in AQP4+ NMOSD.


  1. Pittock S, et al. MSVIRTUAL2020, FC01.01.
  2. Pittock SJ, et al. N Engl J Med. 2019 Aug 15;381(7):614-625.