Investigational drugs in development to prevent neuromyelitis optica relapses.

INTRODUCTION: In the short time since 2014, three pivotal, worldwide studies in neuromyelitis optica spectrum disorders have been launched: eculizumab, SA237 and inebelizumab, each based on a unique mechanism.

AREAS COVERED: In this review, we provide a discussion on the trial data available for each drug, a brief description of the trial design, and our expert opinion on the potential benefits and risks.

EXPERT OPINION: Eculizumab, a C5 complement inhibitor, may prove useful in the treatment of intractable cases of NMOSD, but physicians must be aware of the known risk of meningococcal infection. SA237, an interleukin-6 receptor blocker, may be effective at reducing relapse risk, and also has the potential to reduce neuropathic pain in NMOSD. Inebelizumab, a B cell depleting agent, has never been tested in NMOSD, but based on extensive evidence of efficacy with B cell depletion using rituximab, inebelizumab is expected to work at least as well.