People with relapsing-remitting multiple sclerosis have an average of one relapse every two years, but an existing medication may help make relapses even less frequent.
A small recent Phase 3 clinical trial showed multiple sclerosis (MS) patients had fewer relapses when using a drug originally approved as a treatment for cancers like non-Hodgkin lymphoma and chronic lymphocytic leukemia.
The study, published in the journal The Lancet Neurology, found that taking the monoclonal antibody rituximab every six months led to better outcomes than leading MS treatment.
In addition to preventing future relapses, rituximab would also make MS treatment easier. Patients wouldn’t have to rely on a daily pill or more frequent infusions.
Lead study author Anders Svenningsson, MD, PhD, an adjunct professor at Karolinska Institutet in Sweden, told Verywell that before the trial, patients would travel almost 200 miles for an infusion and repeat the trip once every month.
To conduct the study, researchers recruited 195 MS patients from 17 Swedish hospitals.
Half received 250 milligrams of Tecfidera, a common twice-a-day oral treatment that’s approved for MS in the U.S.
The other half received 1,000 milligram doses of rituximab, followed by 500 milligram infusions every six months.
After three years of followup, researchers determined relapse was less common among the rituximab group than the Tecfidera group. Specifically, 16 people taking Tecfidera experienced relapses compared to 3 people taking rituximab.
The study defined relapses as new or worsening neurological symptoms associated with multiple sclerosis. These symptoms had to occur for more than a day after being at least 30 days free of disease activity.
Additionally, MRI imaging showed that people taking rituximab had less damage and scarring in their brains and spinal cord than those taking Tecfidera. They also reported fewer side effects.
“We were not surprised that rituximab was effective, but since we put it against one of the most potent MS drugs, but we were surprised the effect was that much,” said Svenningsson.
He thinks rituximab may have worked better than expected because the patients in the trial were very early in their disease progression. Almost 95% of trial participants enrolled after their first multiple sclerosis symptoms.
“The take-home message, I would say, is the treatment is of high efficacy when done as early as possible,” Svenningsson said. “We saw almost a complete obliteration of disease activity, which is very encouraging.”
Research has supported the use of rituximab for MS for years. This is just the first study to show it works better than existing MS treatment.
A 2021 review showed that people with relapsing-remitting multiple sclerosis benefit from the antibody because it reduces inflammation and lesions in the brain.
A 2018 observational study found that 74% of patients were relapse-free after rituximab treatment. The study authors noted a quarter of the 89 participants experienced “mild and self-limited” side effects such as infusion-related reactions.
Even though rituximab isn’t approved by the Food and Drug Administration (FDA) to treat MS, using a drug to treat a condition beyond its indication is a legal and common practice in the medical community.
One in five medical prescriptions involves off-label drugs. Controlled substances such as opioids are an exception, however, and must be used as directed.
Since getting a drug approved is a long and arduous process, repurposing an existing drug is a quicker and cheaper way of getting patients the treatment they need.
According to Svenningsson, FDA-approved multiple sclerosis drug Ocrevus (ocrelizumab) is similar to rituximab because it binds to the same target: B cells. Yet Ocrevus is many times more expensive than rituximab.
“It’s just not reasonable that we should use drugs that cost 10 times as much just because it’s the ‘only’ option,” he said.
Svenningsson said his team is working on spacing out rituximab infusions even further. If successful, there is a chance the infusion can be scheduled every couple of years or on an on-demand basis.
“We could induce some kind of long-term remission, which would be the best outcome,” he said.