Dec. 12, 2005 -- An immune system-suppressing drug may slow progression of multiple sclerosis, new research suggests.
Using magnetic resonance imaging, researchers showed that new brain lesions that indicate multiple sclerosis (MS) progression were reduced by more than half in 12 of 14 patients treated with the drug Imuran.
The drug is now used primarily to prevent rejection in transplant patients and in the treatment of patients with rheumatoid arthritis and other autoimmune disorders.
Imuran has been studied by MS investigators for several decades. Previous studies have shown that Imuran can reduce relapses in patients with multiple sclerosis. However, the new research is the first to show that the drug can slow disease progression by decreasing the presence of new lesions.
Study researchers say their findings are similar to other studies' results looking at the use of injectable interferon-beta and brain lesions in MS. But a spokesman for the National MS Society tells WebMD that larger studies are needed to prove this.
"If these findings are confirmed then we would have a less expensive oral medication that is of comparable benefit to the current treatments," says John Richert, MD. "These data show that it is worthwhile to invest the resources to try and prove that this drug alters disease progression."
It is not clear what causes MS, but most experts now believe it to be an autoimmune disease - one in which the immune system mistakenly attacks the person's own tissue rather than foreign invaders.
It is believed that inflammation drives the destruction of the protective coating, known as myelin, surrounding the nerves in key areas of the brain and spinal cord. This destruction leaves the nerves unable to send electrical signals. This results in problems such as muscle movement, coordination, balance, vision, memory, and thinking.
In its later stages MS can leave patients paralyzed, but it is not usually fatal.
Reducing Brain Lesions
The patients in the new study had the most common form of the disease, known as relapsing-remitting MS. During relapses, new symptoms can appear and old ones often resurface or worsen.
All of the patients in the study had early relapsing-remitting MS, and all had monthly MRI scans beginning six months before they began taking Imuran. Only those with active lesion formation at the time of evaluation were included.
New lesion formation was also measured monthly for the first six months of treatment, and total lesion activity was measured for six additional months.
Luca Massacesi, MD, and colleagues of the University of Florence concluded that the treatment induced "remarkable new brain lesion reduction," which remained stable during the entire year of treatment.
None of the patients dropped because of side effects.
The study is published in the December issue of the journal Archives of Neurology.
Treatment Deserves Closer Look
"The new brain lesion suppression observed in the present study is similar to that observed with different interferons using the same study design," Massacesi and colleagues wrote. They further noted that a head-to-head study comparing Imuran with one of the widely used interferons would be useful.
Richert, who is vice president for research and clinical programs at the National MS Society, agrees.
"We haven't had data indicating that this drug is capable of altering the long-term course of MS," he says. "This research does not prove that it does, but the question deserves a closer look."