Two major patient trials of an experimental drug for the relapsing-remitting form of multiple sclerosis have found the oral medication significantly improves patients' symptoms.
The studies, both published in Wednesday's issue of the New England Journal of Medicine, show that the drug BG-12 reduces the rate of annual relapses and the number of brain lesions that are hallmarks of the disease.
The studies show BG-12 (dimethyl fumarate), a drug long used to treat psoriasis in Europe, cut the annualized rate of relapses among MS patients participating in the studies by 45 to 50 per cent compared with MS patients given a placebo.
"That is a very robust reduction in relapses," said Dr. Robert Fox, director of the Mellen Center for Multiple Sclerosis at the Cleveland Clinic in Ohio and principal investigator of the CONFIRM study.
"It's not a cure. None of our therapies is a cure for MS at this point. But it appears to be a greater reduction than what we see with injectable therapies, which [offer] roughly a 30-per-cent reduction in the annualized relapse rate."
Fox said patients in the CONFIRM and DEFINE studies who were randomly assigned to receive BG-12 also had considerable reductions in brain lesions – 70 to 90 per cent lower than patients given the dummy pill, depending on the type of brain looked at in MRI exams.
Both studies showed a slowing of the progression of MS-related disability, although only the DEFINE study conducted by European researchers had results considered statistically significant, Fox said in an interview from Paris, where he was attending a medical meeting.
BG-12 was well tolerated for the most part, although some patients experienced flushing of the skin on the chest, neck and face within about 45 minutes of taking the pill, which resolved within 15 to 20 minutes, he said.
More troublesome for patients was gastrointestinal upset, including nausea, vomiting and diarrhea, associated with the drug. Fox said those adverse symptoms seem to peak in the first month after starting the drug and decline in frequency and severity as time goes on.
BG-12, developed by Biogen Idec Inc., must be approved by government regulatory bodies such as the U.S. Food and Drug Administration and Health Canada before it would available to treat patients.
"What this drug appears to provide is a significant step forward in the combination of efficacy, safety and tolerability," Fox said.
"So it appears to be more effective than our standard first-line injectable therapies."
Dr. Paul O'Connor, director of the multiple sclerosis clinic and MS research at St. Michael's Hospital in Toronto, agreed that the efficacy and safety of BG-12 "look pretty good."
O'Connor, who was not involved in either study, said that if approved, BG-12 would be "another tool in the toolbox" for doctors to prescribe to patients with relapsing and remitting MS.
In Canada, there is already another oral MS medication on the market; another, teriflunomide, is in the regulatory pipeline, as is BG-12.
"It's good for MS patients because they could have in Canada within a year maybe three oral options," O'Connor said.
As to which one is best, that could only be determined by comparing the three drugs in a patient trial, he said. "Until you have a head-to-head study, you don't know."