Inebilizumab Results for NMOSD Presented at ECTRIMS, With Public Offering on Way

The European research community rose early Thursday to hear firsthand the results for inebilizumab, the monoclonal antibody under FDA review after receiving Breakthrough Therapy Designation earlier this year to treat a rare, debilitating autoimmune condition called neuromyelitis optica spectrum disorder (NMOSD).

Results from the N-MOmentum Study, presented at the American Academy of Neurology, showed why an independent review panel stopped the trial early, after results showed the drug achieved a 77.3% reduction in risk of patients suffering a disease-related attack compared with placebo.

Lead investigator Bruce A. Cree, PhD, MAS, of the University of California at San Francisco Medical Center, kicked off a plenary session on treatment options in NMO at ECTRIMS 2019, the 35th Annual Congress of the European Committee for Treatment and Research in Multiple Sclerosis, taking place in Stockholm, Sweden. In addition, 6 more abstracts on inebilizumab will be presented during the meeting.

Neuromyelitis optica disorders involve severe axonal damage, primarily to the optic nerve and the spinal cord. Patients experience life-threatening symptoms, including loss of vision, paralysis, and bowel and bladder dysfunction. No approved treatments exist for this condition, although there are other possibilities in the pipeline.

FDA previously granted inebilizumab orphan drug designation, and breakthrough status followed in April 2019. Viela Bio announced August 27, 2019, that FDA had accepted its Biologics License Application for inebilizumab, and last week the company announced plans for an initial public offering. Full results from the N-MOmentum Study appeared this week in The Lancet.¹

As a mechanism of action, inebilizumab uses CD19 as a target for B cell depletion. As explained in a 2016 article in the Journal of Clinical Medicine, many autoimmune disease feature B cells in overdrive, and depleting them has been the hallmark of several new therapies in MS. Inebilizumab has enhanced “antibody-dependent cell-mediated cytotoxicity against B cells.”²

The multinational trial—taking in 99 medical centers in 25 countries—took place between January 2015 and September 2018, involving 230 patients who were randomly assigned to the treatment (n = 174) and placebo groups (n = 56). As Cree explained, no background immunotherapy was permitted in the study. Patients who took part had to have had 1 attack in the prior year or 2 within the previous 2 years. The population was 91% aquaporin-4 (AQP4)-IgG positive, 91% female, and mean age was 43 years at baseline.

The independent data monitoring panel ended the trial prior to full enrollment after 21 (12%) patients in the study drug group suffered an attack compared with 22 (39%) in the placebo group, for a hazard ratio of 0.272 (95% CI, 0.150-0.496; P <.0001). An open-label extension study continues following the end of the randomization period.¹

According to the ECTRIMS abstract, inebilizumab reduced the risk of attack in the AQP4-IgG positive population by 77.3% and in the total population by 72.8% (P <.001). In addition, Cree noted:

• Inebilizumab produced a 63% reduction in disability, a 71% reduction in hospitalizations, and a 43% reduction in lesions as seen in magnetic resonance imaging (MRI).
• After 1 year on treatment with the study drug, 85% of patients were free of an NMOSD attack.
• The most common adverse events included urinary tract infection (19.6%), nasopharyngitis (12.9%), and infusion-related reactions (11.6%). Infusion reactions were most common with the first infusion.
• At 1 and 2 years, 7.5% and 13.4% of inebilizumab-treated patients had IgG levels below the lower limit of normal; Cree said this may point to the need for IgG monitoring if the drug is taking long-term.
• Two patients died during the open-label portion of the study. One death was attributed to NMOSD and the other was attributed to new inflammatory brain lesions of unknown cause. No autopsy was performed, Cree said.

Jorn Drappa, MD, PhD, chief medical officer and head of research at Viela Bio, pointed to the hospitalization data in a statement in advance of the meeting.

“Among the highlights to be presented at the congress are the long-term results from our open-label extension study, building on the previously reported data which demonstrated a reduction in risk of NMOSD attack and reduced disability scores as measured by expanded disability status scale, hospitalizations and new central nervous system MRI lesions when compared to placebo," he said.

References

1. Cree BAC, Bennett JL, Kim HJ. Inebilizumab for the treatment of neuromyelitis optica spectrum disorder (N-Momentum): a double-blind randomized placebo-controlled 2/3 trial [published online September 5, 2019]. Lancet. 2019; doi:http://doi.org/10.1016/S0140-6736(19)31817-3.
2. Chen D, Gallagher S, Monson NL, Herbst R, Wang Y. Inebilizumab, a B-cell depleting anti-CD19 antibody for the treatment of autoimmune neurologica diseases: insights from preclinical studies. J Clin Med. 2016;5(12):107. doi: 10.3390/jcm5120107.