Multiple Sclerosis (MS) is a chronic and often disabling disease that attacks the central nervous system and causes symptoms like numbness, difficulty walking, blurred vision, fatigue, memory problems, and more. Canada has the fifth highest worldwide prevalence of MS, affecting 240 out of every 100,000 people.

Relapsing-remitting MS (RRMS) is the most common type of MS, affecting 85 to 90 per cent of patients. In RRMS, symptoms appear and then partially or completely fade away and the frequency of relapse is highly variable. The goal of treating RRMS is to lessen the frequency of relapses and potentially delay the progression of physical disability.

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For many years, there were only a handful of drugs available in Canada to treat RRMS and they were all given by intramuscular or subcutaneous injection. But recently, several new therapies have been approved by Health Canada, including three drugs that can be taken orally and one drug given through intravenous infusion. These new therapies are changing the landscape of MS treatment in Canada.

What does the evidence show?

When new drugs come on the market, one of the first questions patients, physicians, and health care decision makers ask is how the new drugs compare to the older drugs. To help them answer this question and guide their decisions, it’s important that reliable sources of evidence-based information are available to help them understand the comparative benefits, harms, and costs.

CADTH (#Canadian Agency for Drugs and Technologies in Health) – an independent, not-for-profit producer and broker of health technology assessments – recently published a comprehensive study, with recommendations, comparing the clinical effectiveness and cost-effectiveness of existing treatments and newly available treatments for RRMS.

#CADTH’s review found that, compared to no treatment, all of the drugs reduced the average number of relapses a patient will have in a year (known as the annualized relapse rate or ARR). Specifically, compared with no treatment, ARR was reduced by approximately 70 per cent for  natalizumab or alemtuzumab, 50 per cent for fingolimod or dimethyl fumarate, and 30 per cent for interferons, glatiramer acetate or teriflunomide.

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However, patients, physicians, and health care decision makers need to consider more than just the clinical effectiveness of a new drug. Cost-effectiveness is another important consideration. The annual cost of some of the new drugs is double the cost of existing drugs. CADTH’s analysis shows that interferon beta-1b and glatiramer acetate have clinically meaningful effects on the ARR and are the most cost-effective initial therapies.

And because all drugs have some form of side effect, it is important to consider the adverse events associated with a drug when choosing a treatment. For example, fingolimod may not be suitable for patients with a history of certain heart conditions and, for certain patients, natalizumab may be associated with a potentially fatal brain infection.

What does CADTH recommend?

Below are the key messages from CADTH’s recommendations for drug therapies for RRMS:

• For patients newly diagnosed  with RRMS, start with glatiramer acetate (Copaxone) or interferon beta-1b      (Betaseron or Extavia).
• For patients who do not respond to or are unable to take one of the recommended initial drugs, switch to the other recommended drug.
• For patients who do not respond to or are unable to take both glatiramer acetate (Copaxone) or interferon beta-1b (Betaseron or Extavia), choose one of dimethyl fumarate (Tecfidera), fingolimod (Gilenya), and natalizumab (Tysabri), based on safety and cost considerations.
• Combination therapy should not be used – the review showed no clinical advantage of combination therapy over monotherapy.

It is important to note that at the time these recommendations were made, alemtuzumab (Lemtrada) and teriflunomide (Aubagio) were not yet approved by Health Canada for the treatment of RRMS. The recommendations were restricted to treatments that were approved for RRMS in Canada at the time of the report.

To read more on drug therapies for RRMS, visit www.cadth.ca/ms