Ask the Pharmacist

Q) What can you tell me about the new treatment for migraines?

A) Aimovig (pronounced AIM-oh-vig or also known by its generic name erenumab) is the newest medication designed to prevent migraines and has generated more questions and general anticipation than any other potential new drug entry. This undoubtedly speaks to both the commonality of migraines and the devastation this disorder can have on the lives of those who suffer from them.

Of Canadians, 8.3% (approximately 2.5 million people) report having been diagnosed with migraine by a health professional with a preponderance of those affected being female and more likely to be in their 30’s and 40’s. Not surprisingly, migraine sufferers report that their headaches significantly impact many aspects of their daily life including work, sleep, education and driving and there is an increased chance that these same people will also eventually be diagnosed with depression. As such, it is small wonder that so many are looking for help from new entries in the migraine drug category.

Aimovig is the first drug designed to block receptors for calcitonin gene-related peptide (CGRP) which is a protein that is made within the cells of the brain and the spinal cord amongst other places. CGRP has been implicated as being involved with our ability to feel pain as well as in the relaxation (and hence the dilation or widening) of our blood vessels both of which occur during a migraine.

Tests have shown that CGRP levels spike during a migraine giving researchers the notion that stopping this molecule from exerting its action could be helpful. Aimovig works by attaching to a target molecule (called a receptor) for CGRP, thereby, preventing this protein from exerting its effects.

An analogy to help explain all of this involves a key and a lock. Think of CGRP as the key and its receptor as the lock. When the key enters the lock, the effects of the CGRP occur, namely pain, inflammation and dilation of the blood vessels. Aimovig acts like a piece of gum that gets stuck in the lock, thereby preventing the key from entering and exerting its pharmacological effects. Aimovig is a type of monoclonal antibody treatment which makes it a biological. Biologicals are a group of drugs that have been used for years now in treating both cancers as well as a number of autoimmune type disorders such as rheumatoid arthritis and psoriasis.

Most medications that we currently use to prevent migraines were originally designed to treat other conditions such as blood pressure, depression or seizures. That tends to make them only somewhat effective and also likely to cause unintended effects (e.g. side effects) such as drowsiness and brain fog.

Aimovig seems to have fewer side effects than these other options which are a significant advantage since preventative type medications are by their very nature taken regularly over long periods of time. In fact, the two most common side effects of Aimovig are injection site reactions (such as pain and redness where the needle was inserted, not unlike an insulin or vaccine shot) and constipation, both of which are more easily dealt with than living in the “haze” that other options can cause.

The other major advantage of Aimovig is its long duration of effect. It need only be administered once a month as opposed to daily or even multiple times a day for other preventative drugs. Unfortunately, while Aimovig does seem to work (studies have shown it can reduce migraine frequency by at least 50% in half of patients who use it which equals out to about 1 or 2 less migraines a month) it doesn’t appear to be any more effective than the options currently available.

A disadvantage to Aimovig for some will also be the fact that this drug needs to be injected rather than swallowed orally like a pill. It can be injected at home using an Epipen like device which is very easy to use but the fact remains that most of us do not enjoy poking holes in our skin.

The other major disadvantage is its cost which seems to be an issue with any new drug entering the market. While a Canadian price is not yet available (it was approved by Health Canada in August but is still not available for sale as of now and no definitive future date set as of yet) in the States it costs $575 (US dollars) per month making it a far more expensive option than most other alternatives.

The last thing to consider is the unknowns that any new drug comes with. These include the effects on pregnancy and whether other unintended consequences will occur as the drug is used for many years as opposed to the shorter periods of time during which drug trials are conducted. As of right now, the FDA does not know how Aimovig will affect pregnant women.  They are not telling pregnant females not to use the drug but they have asked the manufacturer to monitor the situation for the next few years which does indicate those who use it are in the proverbial “guinea pig” situation. The drug does take some time to clear your system so women who wish to conceive and not take this theoretical risk should stop the treatment at least five months before becoming pregnant.

As for long term effects most of the concern is related to potential cardiovascular issues as CGRP can also be good for the body in that it leads to relaxed arteries which is conducive to a better blood flow and a lower heart rate. As such, there is a theoretical risk that Aimovig, by blocking CGRP’s action could lead to a heart attack or stroke. This effect has not been observed in the thousands of patients who underwent treatment during clinical trials but that does not necessarily mean that we won’t find this to be a problem to some degree 5 or 10 years from now.

Aimovig may be the first drug of its class to be released but it certainly won’t be the last. At present, there are at least three other similar drugs in the midst of clinical trials all of which work slightly differently in that they “target” the CGRP protein itself rather than the receptor. Some will be administered by injection like Aimovig whereas other entrants will need to be infused at a hospital.

Regardless, it’s wonderful to see that many migraine sufferers will have new hope at getting their lives back in the very near future.