Eculizumab substantially mitigated the risk of relapse in comparison to a placebo and was found to be well-tolerated.
Aquaporin-4 immunoglobulin G-positive neuromyelitis optica spectrum disorder (AQP4-IgG + NMOSD) is an autoimmune central nervous system disorder characterized by relapses that lead to accumulating disability. Chronic immunosuppressive therapy (IST) is the primary treatment for AQP4-IgG + NMOSD, but its effectiveness may be limited due to adverse events (AEs).
In a clinical trial called PREVENT, eculizumab, a humanized monoclonal antibody targeting the terminal complement protein C5, significantly reduced the risk of relapse compared to a placebo in patients with AQP4-IgG + NMOSD. The study was a phase 3, randomized, double-blind, placebo-controlled, time-to-event trial. The safety profile of Eculizumab was similar to that observed in other indications, implying good medication tolerance. These findings are reported in a study published in the journal Multiple Sclerosis.
Eculizumab Monotherapy: Long-Term Efficacy in AQP4-IgG + NMOSD
Throughout the 96 weeks of the study, none of the patients who received eculizumab monotherapy experienced a relapse, in contrast to only 40% of those who were administered a placebo.
Efficacy of Eculizumab Monotherapy in Preventing Relapses
One of 33 patients receiving eculizumab monotherapy experienced an adjudicated relapse after 380 days in the open-label extension (OLE). This group’s adjudicated annualized relapse rate was 0.012 versus 0.625 for the PREVENT placebo alone group. At 192 weeks of eculizumab monotherapy, 96.2% of patients were free from adjudicated relapses.
Improved Measures of Disability and Quality of Life With Eculizumab Monotherapy
Between PREVENT baseline and end, mean Expanded Disability Status Scale (EDSS) and Hauser Ambulation Index (HAI) scores improved with eculizumab monotherapy and deteriorated with placebo alone. Compared to a placebo alone, using eculizumab monotherapy resulted in significant enhancements in the mean scores of the five-dimension three-level index (EQ-5D-3L), EuroQol visual analog scale (EQ VAS), and modified Rankin scale. The EQ VAS and EQ-5D-3L showed sustained improvements with the use of eculizumab monotherapy during the OLE period.
Safety of Eculizumab Monotherapy
AE and hospitalization rates during eculizumab monotherapy were lower than with placebo alone. During the PREVENT and OLE studies, the frequency of severe infections was found to be lower with eculizumab alone than with the administration of a placebo alone. Additionally, no occurrences of meningococcal infections or fatalities were reported among patients who received eculizumab.
Pittock, S. J., Fujihara, K., Palace, J., Berthele, A., Kim, H. J., Oreja-Guevara, C., Nakashima, I., Levy, M., Shang, S., Yountz, M., Miller, L., Armstrong, R., & Wingerchuk, D. M. (2022). Eculizumab monotherapy for NMOSD: Data from PREVENT and its open-label extension. Mult Scler, 28(3), 480-486. https://doi.org/10.1177/13524585211038291