Phase 3 Results for Inebilizumab Show Reduced Risk of Neuromyelitis Optica Spectrum Disorder Relapse

Treatment with inebilizumab (VielaBio, Gaithersburg, MD) reduced relapses of neuromyelitis optica spectrum disorder (NMOSD) by 77% after 28 weeks of treatment. Response to treatment with inebilizumab for NMOSD was safe and effective such that the trial was terminated early as it was deemed unethical not to treat participants in the placebo arm of a phase 3 trial (NCT02200770). After this judgement was made, all participants in the placebo arm began receiving inebilizumab on an open-label extension basis. 

Treatment with inebilizumab also reduced worsening from baseline score on the Expanded Disability Status Scale (EDSS), NMOSD-related hospitalizations, and frequency of cumulative total active MRI lesions. 

Inebilizumab is an anti-CD19, B cell-depleting monoclonal antibody under investigation for the treatment of NMOSD.

In this double-blind placebo-controlled phase 3 study, participants were randomly assigned to receive inebilizumab or placebo. People were eligible to participate if they had NMOSD and were seropositive for AQP4-IgG, or if seronegative for AQP4-IgG had been confirmed as having NMOSD by a 3-member expert eligibility panel. Individuals were excluded from the trial if they were being treated with other immunosuppressants. Treatment with placebo was limited to 6.5 months. Relapse were adjudicated as such by a 3-member independent panel blinded to treatment. Individuals who had a relapse were offered treatment with inebilizumab on an open-label extension basis. 

“The N-MOmentum trial demonstrated the statistically significant and clinically meaningful treatment effect of inebilizumab across both the primary endpoint and key secondary endpoints,” said Bruce Cree, MD, PhD, MAS, professor of clinical neurology at the University of California San Francisco Weill Institute for Neurosciences. “Inebilizumab is the first and only biologic in NMOSD to use CD19 as a target for B cell depletion without the confounding effects of background drug therapies. Inebilizumab substantially reduced the risk of attacks when given as a monotherapy, successfully measuring a strong treatment effect in both attacks and worsening disability.”