Ask the Pharmacist

Q: I have been told that there is a new drug coming to Canada in the very near future for the treatment of Multiple Sclerosis (MS). Is it very much different than the current options that I am using?

A: Unfortunately, Mavenclad (pronounced MAY-ven-clad, with its active ingredient being cldribine) is not that different than some of the current options many people with MS are either already taking or at least considering.

Before going into the specifics regarding this drug, let’s review some of the fundamentals regarding this condition and its treatment. Canada has one of the highest rates of MS in the world with an estimated one in every 340 Canadians living with the disease.

MS is classified as yet another auto-immune disorder, meaning that its symptoms are caused by our immune system. This immune system of ours ideally helps us fight off various bacteria and viruses, but for some it instead starts to attack our body.

Myelin is the covering that protects our nerves from damage and in the case of MS, it is the myelin that is affected. Myelin is essential to the transmission of nerve signals from our brain to all parts of our body so that even if it’s damaged only slightly, we experience symptoms.

These symptoms can be temporary but if the damage is prolonged, then scar tissue can replace the myelin, resulting in permanent nerve disruption to that area of the body.

Why the immune system does this, remains a mystery but is believed to be a result of genetic, environmental, lifestyle and biological factors.

Symptoms vary greatly among individuals both in terms of which ones present and their severity but can include challenges with dizziness/balance, difficulty in thinking, bladder and bowel issues, fatigue, pain, blurring or the loss of vision in one eye (particularly in the central visual field, this is often the first symptom experienced), eye pain or light flashes brought on by eye movement, numbness or tingling in one or more limbs, spasticity (“tightness”) in one or more limbs, weakness, tremor, sexual issues and many others.

MS is subdivided into three categories. The most common form is relapsing-remitting MS (RRMS) which accounts for about 85 per cent of those diagnosed. In RRMS, the disease takes a highly variable course in which there are distinct flare-ups where new symptoms may appear or existing ones worsen followed by a period in which these will either completely disappear or very nearly go away.

With secondary-progressive MS, a patient who was initially diagnosed as RRMS finds that over time, the remissions become less obvious, and their symptoms continue to progress. About half the people with RRMS will start to worsen within 10-20 years of diagnosis.

The last sub-type is primary-progressive MS which is characterized by a slow progressive level of disability without major relapses or remissions right from the initial diagnosis. Treatment usually continues for an indefinite period of time and the drug or drugs may be changed as time goes on depending upon how effective they are and side effects.

The goals of treatment are to lessen both the frequency and severity of flare-ups, slow progression of disability and, hopefully, decrease the risk of further attacks after the initial episode.

While there are many drugs now approved to treat MS, which one to use and when to start treatment, is controversial. In fact, a number of patients have been given a list of several names and are told to read up about them and to choose from there. Many also choose not to treat perhaps turned off by the side effects that are possible, the uncertainty regarding any treatment's effectiveness and the costs associated with all of these drugs.

Regarding costs, we have two notes to add. There are programs to help off-set the expense (which is usually thousands of dollars per month) that most pharmacies and doctors can help you access. Be grateful you do not live in the United States; Canada is not cheap compared to the rest of the world but a drug like Avonex costs $1,800 per month here and more than $6,000 down south.

Mavenclad is the newest oral option (many of the first-choice MS drugs are by injection) for RRMS. In terms of effectiveness, it prevents roughly 19 relapses for every 100 patients who take it for one year. This is more effective than Aubagio (17 fewer) but less so than Gilenya (22 fewer).

Mavenclad has a very unique dosing schedule based on weight that involves taking tablets on the first four or five days of Week 1, followed by none over the next three weeks and then a fifth week which is the same as the initial one. After one year, the cycle repeats.

At this point, treatment with Mavenclad is usually limited to two years only, as there is a lack of evidence to support going beyond that time frame. Like many MS drugs, inactivated vaccines are fine to take but live ones should be completed at least six weeks before starting Mavenclad.

Regular blood work will be required to monitor white blood cell levels which may go too low, leaving you more likely to get an infection. Other side effects of note, include nausea, headache, herpes zoster and flu-like symptoms. It can cause birth defects so women of child-bearing age will need to use some form of contraception while on the drug and for at least six months after finishing, and men must take precautions if their partner could become pregnant as well, of course.

Mavenclad is likely to be reserved for patients who are continuing to have relapses while taking first-choice-type options, such as interferon beta-1a (Avonex, Rebif), interferon beta-1b (Betaseron, Extavia) or Copaxone.

For more information about this or any other health-related questions, contact the pharmacists at Gordon Pharmasave, Your Health and Wellness Destination. Also check the website at www.gordon-pharmasave.com/ and the Facebook page at www.facebook.com/GordonPharmasave/?fref=ts