NATIONAL HARBOR, MD. – – including a common genetic variation linked to reduced response to anti-CD20 therapies, new research shows.
The phase 3 N-MOmentum Study previously showed safety and efficacy for inebilizumab over placebo in more than 200 adults with NMOSD.
A new analysis focused on participants who were carriers of either the F/F allele, which is known to reduce the effectiveness of certain monoclonal antibodies, or the rs396991 V-allele, which has not been associated with a reduced response.
Dr. Bruce Cree
Results showed no significant differences between the two carrier groups in NMOSD activity, including annual rates of new/enlarging T2 lesions, during the trial and up to 6 months after treatment with inebilizumab.
“These data illustrate how mechanistic precision in treatment design can help patients gain benefit from their regimen regardless of the genetic make-up of their immune systems,” coinvestigator Bruce Cree, MD, PhD, professor of clinical neurology at the University of California, San Francisco, Weill Institute for Neurosciences, said in a press release.
“The combination of efficacy, safety, and ease of administration with twice-yearly infusions make this product an excellent choice for first-line therapy in NMOSD,” Dr. Cree said.
The findings were presented at the annual meeting of the Consortium of Multiple Sclerosis Centers.
B-cell depletion
Inebilizumab has also been approved in China, Japan, and South Korea for the treatment of NMOSD, a rare and severe autoantibody-mediated disease of the central nervous system that includes NMO and related syndromes.
The drug’s B-cell depletion capability is credited with reducing inflammation, lesion formation, and astrocyte damage. The latter can cause severe effects in an NMOSD attack, affecting the optic nerve, spinal cord, and brain.
Manifestations can range from loss of vision to paralysis, loss of sensation, bladder and bowel dysfunction, nerve pain or respiratory failure. Attacks can also result in cumulative damage and disability, the researchers noted.
Results from the original double-blind trial of 230 adults with NMOSD showed that treatment with inebilizumab demonstrated efficacy and safety over placebo. However, questions have remained regarding the treatment’s effectiveness, specifically among patients with the FCGR3A (F/F) allele, a genetic variant that encodes the low-affinity Fc gamma receptor IIIa.
This genotype is known to reduce the effectiveness of certain monoclonal antibodies and anti-CD20 therapies, notably rituximab, in disorders such as NMOSD.
With up to 40% of White and Black individuals known to carry the F/F allele, inebilizumab was designed specifically with that risk in mind, with strong binding to the allele.
Although inebilizumab joins two other Food and Drug Administration–approved treatments for NMOSD – eculizumab and satralizumab – neither of those have a mechanism involving the FCGRA3 receptor. Therefore, those drugs are not a concern for individuals with those genotypes.
To evaluate inebilizumab’s effects among patients with the F/F allele, Dr. Cree and colleagues assessed data on a subset of 142 patients from the N-MOmentum trial.
The study included a 28-week randomized controlled period in which adults with NMOSD received either 300 mg of intravenous inebilizumab or placebo on days 1 and 15, followed by an optional open-label period of at least 2 years. During the open-label phase, all patients received 300 mg of IV inebilizumab every 26 weeks.
Of the 142 patients in the genetic analysis, 104 received inebilizumab and 38 received placebo. In addition, 68 group participants were carriers of the F/F allele, while 74 carried the rs396991 V-allele.