I recently wrote an article about the diagnosis and preventive treatment of migraine headaches. In that article, we discussed treatment of acute migraine headaches with acetaminophen, non-steroid anti-inflammatory drugs, triptans, antiemetics, and corticosteroids. We also spoke about when to initiate preventive therapy with medications such as amitriptyline, Depakote, beta blockers, topiramate, valproic acid, and Botox injections.
All of the aforementioned medications can work great for prophylaxis of migraine headaches, however, in some patients, they just do not work, or they have adverse effects that cannot be tolerated.
Today we will discuss the newest option for preventive treatment of migraines, which is Erenumab (Aimovig). This medication is approved as a once-monthly subcutaneous injection that works as a monoclonal antibody opposing the activity of calcitonin gene-related peptide (CGRP).
Erenumab binds to the same receptor that CGRP does and blocks it from being activated, which therefore prevents it from eliciting its physiologic effects. As many of you know, especially those who went through Unit 3 at Southern Illinois University School of Medicine’s PA program, calcitonin gene-related peptide is quite prevalent in the trigeminal nerve ganglia, and when activated it is a strong vasodilator and signals pain, which spread across the cerebrum through cortical spreading depression. (I can still remember going through the pathophysiology is oral examinations in PA school!)
Research has shown that levels of CGRP are elevated during acute migraine episodes, and in addition, studies showed that those that have been given an IV dose of calcitonin gene-related peptide have subsequently had migraine headaches.
Approval of Aimovig was based upon three randomized, double-blind, placebo-controlled trials in adult patients with episodic migraines (4 to 14 migraines monthly) and those with chronic migraines (>15 migraines monthly).1In all three trials, those who received once-monthly injections of Erenumab had a significantly reduced number of migraines compared to those on placebo.1
Another trial was completed with patients who in the past had failed two to four different medications for migraine prophylaxis either due to ineffectiveness or due to adverse effects. This study revealed that over 9-12 weeks of treatment that more patients had over a 50 percent reduction of migraine headache frequency compared to past treatment as well as placebo.1
The dosage of Erenumab is recommended to be 70 mg subcutaneously injected monthly into the abdomen or thigh.Some patients may benefit from 140 mg once monthly (two subsequent injections of 70 mg) as well.
The most common adverse effect in trials with Aimovig was injection site reactions in 5 to 6 percent of patients and constipation in 1 to 3 percent of patients.Antibodies to Erenumab occurred in 6.2 percent of patients who received the 70 mg dose, and in 2.6% of those who received the 140 mg dose.1
One patient during the study who had significant risk factors for cardiovascular disease died from a cardiovascular event. As we talked about above, CGRP is a potent vasodilator, and by blocking this effect, it could theoretically lead to vasoconstriction, leading to an increased risk of a cardiovascular or cerebral ischemic event.
Overall, the novel medication Erenumab (Aimovig) has been shown through trials to reduce migraine headache frequency in those who suffer from episodic and chronic migraines. It also has been seen to be an alternative option for symptomatic relief in patients who may have failed several other options for prophylactic therapy. However, there is no current head to head studies available comparing Aimovig to other well-known options for prophylaxis of migraine headaches. The long-term safety will need to be accounted for as well, especially in those with a history or known risk factors of cardiovascular disease.
If you enjoyed this article and would like to see more work such as this on novel medications, let us know!
Until next time!
• The Medical Letter. Erenumab (Aimovig) for Migraine Prevention. Volume 60. Accessed: June 13, 2018.
• The Calgary Guide. Migraine Headaches. http:// calgaryguide.ucalgary.ca/migraines-and-auras-pathogenesis-and- clinical-findings/. Accessed: June 13, 2018.
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