10/05/2011 05:03 EDT | Updated 12/05/2011 05:12 EST

New MS drug shows modest effect on relapses, disability in clinical trial

TORONTO - A new drug for multiple sclerosis cut the number and frequency of relapses and slowed the progression of disease in some patients taking it, a new study shows.

As a group, people with relapsing-remitting MS who were randomly assigned to take the as yet unapproved drug, teriflunomide, experienced a 31 per cent reduction in relapses compared to people who were given fake pills — placebos.

Progression of the disease was reduced by nearly 30 per cent in patients receiving the higher of two doses of teriflunomide tested in the trial.

The researchers who conducted the study acknowledged the results were "modest." But principal investigator Dr. Paul O'Connor said the findings suggested the drug is about as effective as the licensed therapies currently available to treat the debilitating disease.

And this one has the advantage of being a pill. There is only one other licensed MS drug that is given as a pill; most are given by injection.

The combination of the more convenient route of administration and the benefit shown means the drug will make a difference for some MS patients if manufacturer Sanofi-aventis brings it to market, O'Connor said.

"I think it will allow patients to go on a medicine that's more convenient than an injectable agent which is at the same time modestly effective and safe," said O'Connor, who heads the MS clinic at Toronto's St. Michael's Hospital.

"There is always a tradeoff between effectiveness of MS drugs and safety. And what we found is that more effective MS drugs always carry with them safety issues."

Dr. Jock Murray, an MS expert in Halifax, said the drug has the potential to become a first-line treatment for the disease.

"The point is this: Within the two years (of the study), they already saw a reduction in disability," said Murray, the former head of Dalhousie University's MS clinic.

"Now two years is very short. ... Patients have the disease for up to 40 years. To see a change in the disability is very important because we haven't seen it in the other drugs."

The question remains, though, what manufacturer Sanofi-aventis will charge for the teriflunomide, if and when it brings the drug to market. Murray suspects it won't be cheap: "They're all expensive."

Sanofi funded the multi-country trial, the results from which were published Wednesday in the New England Journal of Medicine.

Developing therapies to treat the autoimmune disease has proven to be a significant challenge.

Drug developers need to hit a delicate balance: dialling down the autoimmune response that triggers damage to the brain and central nervous system without leaving the individual open to infections and ailments that can strike when a body's immune responses are lowered.

Tim Coetzee, chief research officer for the U.S. National Multiple Sclerosis Society, suggested this drug would be a welcome addition to the treatment options available if it is brought to market.

For Coetzee, one of the benefits is that teriflunomide works differently in the body than MS drugs already licensed. That opens up the possibility it might be useful in combination with other treatments, though additional studies to assess safety would be required.

"We're not there yet," Coetzee said in an interview. "But I'm a natural optimist who would say that, if approved, having this along with the other agents on the market allows you to think about new ways of treating the disease."

"One of the challenges of MS is that it's widely variable. And consequently some individuals respond differently than others. And so having another treatment option available that would show effectiveness for relapsing forms of the disease would be an important step forward."

The study did not look at whether the drug was useful for people with progressed forms of multiple sclerosis. Coetzee said that patient group is badly in need of therapeutic options and the National MS Society is dedicating funding to try to spur development of drugs that would be effective for them.

The study enrolled 1,088 patients with MS, ranging in age from 18 to 55 years of age. They had to have had at least one relapse in the previous year or two within the previous two years to qualify for inclusion.

A relapse is defined as either the appearance of a new symptom of the disease or a worsening of symptoms that had previously been stable. Symptoms include physical weakness or numbness, extreme fatigue, loss of vision and cognitive impairment.

The subjects were randomly assigned to one of three groups, receiving either a placebo, a seven milligram dose of teriflunomide or a 14 mg dose.

The researchers followed the patients for two years, comparing among the groups the length of time to relapse, frequency of relapse, disability progression and fatigue levels. As well, they used magnetic resonance imaging — MRI — to chart changes in the volume of MS-related lesions in the patients's brains.

People on both doses of the drug had a longer interval to their next relapse and more patients getting the drug remained relapse-free than did people in the placebo group. Fewer people in the drug groups showed disease progression and they had fewer active brain lesions.

On the issue of fatigue, however — a major problem for people with MS there appeared to be no differences among the groups.

The drug appeared to be safe and well-tolerated by people who took it, the researchers said. There were no deaths in the trial, and no serious health problems that could be attributed to the drug.

The most common complaints among people who took the drug were diarrhea, nausea and hair thinning. No one dropped out of the study because of that last complaint, O'Connor said.