Early diagnosis of multiple sclerosis can change the lives of people living with this chronic disease of the central nervous system.
"Today, there is a huge urgency to make the diagnosis because we know that early and aggressive treatment can alter the course of the disease," says MS specialist and University of Alberta assistant clinical professor Dr. Brad Stewart. "Back 15 or 20 years, diagnosis was less urgent because we had nothing to offer the patient."
Then, says Dr. Ruth Ann Marrie, the director of the multiple sclerosis clinic of the University of Manitoba Health Sciences Centre, "treatment largely focused on acute management of relapses — those times when people presented with sudden worsening of symptoms like vision loss, limb weakness or numbness. We tried to help them manage some of the chronic symptoms like fatigue and difficulty in walking. We didn’t have medication that we thought could alter the long-term course of the disease."
In 1995, the first drug treatment that could modify the disease was approved. Shortly afterwards, three more drugs of the Interferon type were added. In 2006, a fifth drug was approved.
"all five" — Avonex, Betaseron, Copaxone, Rebif and Tysabri — "are drug therapies that attenuate the disease by helping control the intensity and frequency of attacks," says Stewart Wong, the Multiple Sclerosis Society of Canada’s media and public relations national senior manager. "When you treat MS earlier with some of these disease-modifying therapies, the course of the disease is easier to manage and you have a better quality of life. . . . The mid-1990s opened the way to a sustained period of hope and progress in medicine, the course of research and how people can live with the disease."
But Vancouver MS specialist and former medical director of the city’s MS clinic Dr. Stanley Hashimoto says the impact of the therapies introduced in the mid-90s was relatively modest. "Their impact was exaggerated significantly through a lot of marketing," he says. "We needed something that had an actual benefit in terms of therapy and disease modification."
Dr. Paul O’Connor, the multiple sclerosis program director of St. Michael’s Hospital, Toronto, and president of the Canadian network of multiple sclerosis clinics, agrees "these drugs have modest effectiveness, but their introduction in 1995 did mark the advent of a new era (in MS treatment)."
The newest drug to be approved, Tysabri, is the most effective, says Marrie. "But, often with greater benefit comes greater risk," she adds, "so we are moving into an era where treatment becomes increasingly complex. The first four agents approved for the treatment of MS are generally well tolerated and safe over long-term use. The newest medication is associated, relatively rarely, with the risk of a potentially life-threatening brain infection for which there is no known curative therapy."
"Drugs like Tysabri are more effective but there are safety issues," says Hashimoto, also citing the risk of the brain infection progressive multifocal leukoencephalopathy (PML).
To date, there have been 24 cases of PML, four of them fatal, substantially fewer than the estimated risk of one in a 1,000 for patients taking Tysabri. "The concern is that the number of cases of PML seems to be going up," says Hashimoto, noting that the number jumped by 10 in one day. "That’s when you start to wonder about the benefit/risk ratio. But, if the condition is diagnosed really early and the drug stopped, patients can recover quite well."
The next generation of drugs is "looking even better," says Stewart. "all the years of research are really bearing fruit. We may not have a cure yet, but if you can get someone to go into remission 90 or 95 per cent of the time, that’s a whole lot better than we have now. And we have also had some advancement in how we treat secondary progressive MS. We now have an oral medication that works up to 70 per cent of the time to treat exacerbations."
Marrie, too, is hopeful about future treatments for MS patients. she anticipates more choices in treatments in the next decade. "We will have a better understanding of which drug (is best) for which patient. We are trying to use our growing knowledge of the immunology of the disease to create targeted therapies. We are encouraging more researchers to work in the area to accelerate our understanding of the disease, so that we can work toward a cure. "are we going to solve this tomorrow? no. But have we made progress in terms of therapies and our understanding of the genetic and environmental factors involved? yes, yes."
"There are more drugs in trial now than has ever been the case," says O’Connor. "Soon, we’re going to have a lot of choices for treating patients with (relapsing/remitting) MS. The next great challenge is to find disease-modifying drugs for progressive MS."
Multiple sclerosis fact box
- Multiple sclerosis is an unpredictable, often disabling disease of the central nervous system.
- MS attacks the myelin, the protective covering around the nerves of the central nervous system.
- Myelin repair and regrowth takes place in the early stages of MS.
- a complex interplay of genetic susceptibility and environmental factors is increasingly considered to be the underlying cause of the disease.
- Canadians have one of the highest rates of multiple sclerosis in the world. An estimated 55,000 to 75,000 Canadians have multiple sclerosis.
- MS is the most common neurological disease affecting young adults in Canada.
- Every day, three more people in Canada are diagnosed with MS.
- Women are more than three times more likely to develop MS than men.
- MS can cause loss of balance, impaired speech, extreme fatigue, double vision and paralysis.
- MS was first identified and described by a French neurologist, Dr. Jean-Martin Charcot, in 1868.
— Source: The Multiple Sclerosis Society of Canada website, mssociety.ca
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