A new study presented last week during the American Academy of Neurology’s 67th Annual Meeting in Washington, DC provides new treatment strategies for multiple sclerosis (MS) using a monoclonal antibody already used in some MS patients.
MS is a disease characterized by the destruction of insulating covers on nerve cells by the immune system. Relapsing-remitting MS is characterized by clearly defined attacks of decreasing neurologic function (replases) followed by partial or complete recovery periods (remissions). Natalizumab is a drug used for treating relapsing-remitting MS, usually administered by intravenous infusion once per month that reduces the ability of inflammatory immune cells to enter the brain and affect nerve cells. The drug was approved in 2004 by the U.S. Food and Drug Administration and has been proven effective in treating MS relapse, vision loss, and cognitive symptoms. Nevertheless, extended (longer than two years) use of this medication is associated with an increased risk for progressive multifocal leukoencephalopathy (PML), a rare but severe complication caused by JC virus infection that takes advantage of this immunodepression in the brain.
A team of researchers led by Dr. Lana Zhovtis-Ryerson, assistant professor of neurology at NYU Langone’s Multiple Sclerosis Comprehensive Care Center reported on an ongoing multiple center study of close to 2,000 patients in which they extended the dosing schedule of natalizumab to between 5 and 8 weeks. More specifically, Dr. Zhovtis-Ryerson and colleagues are retrospectively comparing patients in from ten U.S. MS treatment centers, collecting data every 4 weeks in a combination of schedules.
The treatment efficacy at this point appears similar to standard schedule (every 4 weeks) with comparable rates of symptomatic MS activity and new lesions in imaging studies. Extended schedule groups had no cases of PML, while the standard schedule group had 2 cases reported. There were no other major adverse effects seen in any group.
Nevertheless, while these differences in safety between schedules are encouraging, statistical significance was not reached. Consequently, further research is needed to ascertain the maintenance of natalizumab efficacy with a more favorable safety profile.