After coping with multiple sclerosis for four years without drug therapy, Vancouver's Gabrielle Veto, 42, started a beta interferon drug regimen in 2000 when a debilitating relapse temporarily left her unable to feel or use her hands.

"It was scary," said Veto. "When you can't feed yourself and you can't scratch your nose, you realize [MS is] a very serious disease and the consequences will last a lifetime."

Veto relies on beta interferons — widely used to treat relapsing-remitting multiple sclerosis (RRMS) — to reduce the number of relapses she experiences. The drugs were also thought to slow the progression of the disease, but a new study by the University of B.C. throws doubt on the impact of beta interferons on multiple sclerosis in the long-run.

The report by researchers at the UBC Hospital MS Clinic and Brain Centre shows the drugs may not have any bearing on the long-term disabling effects of the disease. RRMS is the most common form of multiple sclerosis, affecting around 85 per cent of MS patients in the country, according to the MS Society of Canada.

The study gathered health records from over 2,600 patients in B.C. spread over a 13-year period. Data sources included the B.C. Ministry of Health, PharmaNet, and the B.C. Multiple Sclerosis database. The report will offer people with multiple sclerosis more realistic expectations of the treatment programs they are on, said Dr. Helen Tremlett, one of the study's authors and research chair in neuroepidemiology and multiple sclerosis at UBC.

"There was always initial hope that drug therapy with beta interferons would help slow the disease, but the study's results now seem to indicate otherwise," she said.

Beta interferon — also known as interferon beta-1a — drugs were first used to treat multiple sclerosis in the early and mid-1990s after short clinical trials showed they reduced relapse rates and brain lesions. Periodic relapses often bring about the full range of multiple sclerosis symptoms in patients, such as muscle weakness, fatigue, numbness, and problems with speech before recovery. The drugs are sold under a variety of trade names, including Avonex, Rebif and Cinnovax.

Tremlett insists the other benefits of beta interferons in treating symptom relapses remain unchanged and there is no reason to say the drugs have absolutely no long-term impacts. The study was largely focused on measuring levels of physical disability among people with multiple sclerosis, she said, but excluded elements like cognition, quality of life, memory, and ability to work.

"MS is a very difficult disease to measure," she said. "There's a whole range of things out there that the drugs may benefit. Mobility is a very important outcome, but you can imagine it's not everything."

However, the UBC study findings contradict another study published earlier this month by the Neurological Institute C. Mondino in Pavia, Italy, which concluded that disease-modifying therapies using drugs like beta interferons reduced the risk of RRMS progressing to secondary progressive multiple sclerosis (SPMS), a form of the disease which sees disability progress more steadily in patients.

The Italian report combined research and data from three multiple sclerosis centres in Italy and involved nearly 1,200 patients. The study found that those who received treatment were "significantly less likely" to develop SPMS. Over a 10-year period, nearly 20 per cent of the patients observed who did not undergo drug therapy developed SPMS compared to only three per cent of those who did take the medication.

Although the two reports came to different conclusions, neither of the studies is incorrect, according to Dr. Timothy Coetzee, chief research officer at the National MS Society in the United States. The seemingly conflicting results underscore the variability of multiple sclerosis that makes it frustratingly difficult to study, he said.

"My view [on the two studies] is that both tell us we still have a lot to learn about MS," Coetzee said. "This calls for research into personalized medicine so we can try to tease out individual genetic differences that determine how the disease progresses and match a person's genetic makeup to a specific kind of therapy."

Genetic differences between the Canadian test subjects and their Italian counterparts could have played an important role in the final outcome of the reports, he said. It might take a global study of all people who have MS to be able to come close to finding definitive insights into the disease, Coetzee explained.

"We don't know if there are other pathways the disease can use to bump out the beneficial effects of drugs like beta interferons," he said. "We don't know because of genetics. There are questions we don't have answers to and we need to find out. Unfortunately, we are not there yet, but I'm optimistic we will get there sooner or later."

Meanwhile, Gabrielle Veto remains undaunted by the results of the UBC study and her future prospects as a person living with multiple sclerosis. Like Coetzee, the report validated her opinion that more research needs to be done.

"We can't cure MS yet," she said. "In some ways it doesn't surprise me, because these are only treatments."

Veto confessed she is not sure if beta interferons are slowing the course of her RRMS, but said the drugs have helped reduce the number of measurable relapses she experienced from 25 before 2000 to just four in the last 12 years. She will continue with her drug therapy in spite of the UBC report until she can find a better alternative with help from her neurologist, she said.

"I think I need more information at this point," she added. "It's a credible study, but it's only one study. I'm not sure if making a health decision based on one study is the best route to go. Has it given me food for thought? Absolutely, but I'm not 100 per cent sure of what I should do."

mvinkinlee@vancouversun.com