THURSDAY, Sept. 26, 2024 (HealthDay News) -- Rituximab and ocrelizumab, two drugs often used to treat multiple sclerosis (MS), may be useless for people with the primary progressive form of the disease, a new study contends.
French researchers saw no difference in terms of any slowdown in MS progression between patients with primary progressive MS who took the medications for four years and those who did not.
Given that these drugs -- both from a class called anti-CD20 infusion therapies -- can be expensive and come with side effects, the researchers now question their continued use by these MS patients.
“Anti-CD20 therapies are widely prescribed, in part because there are few alternate treatments," said study author Dr. Laure Michel, of Rennes University in France. "However, our study suggests they may not slow disability from worsening for people with primary progressive MS.”
The findings were published Sept. 25 in the journal Neurology.
Multiple sclerosis is a progressive, debilitating illness where the body's immune system attacks and destroys the sheath of myelin that protects nerves.
About 10% to 15% of patients experience what's known as primary progressive MS, characterized by a steady worsening of symptoms and disability, without periods of recovery or remission.
Anti-CD20 infusion therapies like rituximab and ocrelizumab work by targeting a protein called CD20, found on some immune-system white blood cells called B-cells. It's been thought that reducing the numbers of these cells might curb the immune system's attack on myelin.
Ocrelizumab is approved by the U.S. Food and Drug Administration (FDA) for primary progressive MS, but rituximab is not.
However, rituximab (approved for autoimmune illnesses such as rheumatoid arthritis) is often used "off label" by patients with this form of MS.
The new study involved almost 1,200 patients with primary progressive MS who averaged 56 years of age. None had been on any MS medication in the two years prior to enrolling in the study.
Over the four years of the trial, 295 patients were treated with rituximab, 131 were treated with ocrelizumab and 728 were left untreated.
Their level of disability was tracked on a standard 0-10 score, with 0 being no disability and 10 being death due to MS.
The study found no differences in the rate at which patients' disability scores advanced, regardless of whether they were taking one of the two medicines or not.
The study group was still too small to draw definitive conclusions, however, and a larger trial is needed to confirm these results, the French team noted.
In the meantime, research into new drugs that can truly help people with primary progressive MS is essential, Michel believes.
“MS is a disabling disease, so treatments that slow the progression to worse disability are sorely needed,” she said in a journal news release.
More information
Find out more about the treatment of MS at the Cleveland Clinic.
SOURCE: American Academy of Neurology, news release, Sept. 25, 2024
