Inebilizumab Gets Breakthrough Designation for Neuromyelitis Optica Spectrum Disorder


The designation was granted by the FDA based on the results of the largest study ever conducted with monotherapy in NMOSD, which were favorable for the anti-CD19 antibody.

Dr Jorn Drappa

Jorn Drappa, MD, PhD, chief medical officer and head, Research and Development, Viela Bio

Jorn Drappa, MD, PhD

The FDA granted a breakthrough therapy designation to inebilizumab, an anti-CD19 antibody previously known as MEDI-551, in development as a monotherapy for the treatment of neuromyelitis optica spectrum disorder (NMOSD).1

The rare, life-threatening autoimmune disease, which affects the central nervous system (CNS), is without an approved therapy or cure, making the development of this humanized monoclonal antibody a notably one. The designation was granted by the FDA based on the findings of the largest study ever conducted with monotherapy in NMOSD (NCT02200770).

“Inebilizumab is a humanized monoclonal antibody designed to bind with high affinity to CD19 and deplete a broad range of B cells, including autoantibody-secreting plasmablasts and CD19-expressing plasma cells,” Jörn Drappa, MD, PhD, chief medical officer and head, Research & Development, Viela Bio, the treatment’s developer, said in a statement. “We continue our efforts to bring inebilizumab to patients suffering from this devastating disease for which there are currently no approved medicines.”

In March, Viela Bio announced that the results of the N-MOmentum study will be announced in an oral presentation during a plenary session at the American Academy of Neurology (AAN) 2019 annual meeting in Philadelphia, Pennsylvania. The data will be presented by Bruce Cree MD, PhD, MCR.2

All told, the trial included 231 patients with NMOSD, including those both with and without aquaporin-4 (AQP4)-IgG antibodies, which occur in about 80% of patients with NMOSD. They were then randomized to be administered 2 intravenous doses of inebilizumab monotherapy or placebo, for a 6.5-month treatment period. The primary end point was time from treatment initiation to the occurrence of an NMOSD attack. Afterward, the participating patients were allowed to enter an open-label extension in which all patients receive the treatment every 6 months, which is still ongoing.

Viela Bio announced earlier this year that inebilizumab had met its primary end points as well as all key secondary end points in the N-MOmentum trial. Top-line data showed a 77% reduction in the risk of developing an NMOSD attack in patients treated with inebilizumab compared to placebo. Secondary analysis showed that there were also observed reductions in the worsening of disability for those administered inebilizumab compared to placebo.3

As for safety and tolerability, inebilizumab showed an acceptable and consistent profile. At the time the data were announced, Drappa expressed his pleasure that the findings support the hypothesis that CD19-expressing B cells play an important role in the pathogenesis of NMOSD.

“Importantly, this trial studied inebilizumab as monotherapy, free from the confounding influence of other background immunosuppressive treatments,” Cree, the lead investigator for the N-MOmentum study and professor, Clinical Neurology, UCSF Weill Institute for Neurosciences, said in a statement in January. “The results provide unambiguous evidence of a large reduction in the risk of attack. The results also showed a highly beneficial impact of inebilizumab on disability.”

The treatment was previously under development for relapsing multiple sclerosis (MS), and showed promising results in a phase 1 trial (NCT01585766) as an injection, in which a rapid and sustained reduction of B cells was displayed in patients treated with inebilizumab.


1. Viela Bio Receives U.S. FDA Breakthrough Therapy Designation for Inebilizumab for Treatment of Neuromyelitis Optica Spectrum Disorder [press release]. Gaithersburg, MD: Veila Bio; Published April 18, 2019. Accessed April 18, 2019.

2. Viela Bio Announces Pivotal Study Results of Inebilizumab in NMOSD to be Presented in a Plenary Session at the 2019 American Academy of Neurology Annual Meeting [press release]. Gaithersburg, MD: Veila Bio; Published March 7, 2019. Accessed April 18, 2019.

3. Viela Bio Announces Inebilizumab Achieved Primary and Key Secondary Endpoints in Pivotal Trial in Patients with Neuromyelitis Optica Spectrum Disorder (NMOSD) [press release]. Gaithersburg, MD: Veila Bio; Published January 3, 2019. Accessed April 18, 2019.

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