Erenumab: A New Migraine Preventive Drug

Two Emerging CGRP-Targeted Migraine Medications
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The purpose of preventive migraine therapy is to reduce the number, duration, and severity of migraine headaches.

Yet the currently utilized migraine-preventive medications, like Topamax (topiramate), Inderal (propranolol), and Elavil (amitriptyline), are often not as effective as people would like. In addition, these medications have side effects that commonly lead to discontinuation.

The good news is that researchers are now focusing much effort on developing novel migraine preventive medications. One specific protein they are targeting with these medications is the calcitonin gene-related peptide (CGRP), which has been found to be elevated in people during migraine attacks.

The even better news is that one of these CGRP-targeting drugs is now FDA approved for preventing both episodic and chronic migraine—a truly exciting time for migraineurs and their doctors and loved ones. This drug is called Aimovig (erenumab), and there are three drugs like this one in the pipeline.

Let's take a closer look at erenumab, including how it works, and the results of one study examining its effectiveness.

Erenumab for Preventing Episodic Migraine

Erenumab is a humanized monoclonal antibody that binds to the CGRP receptor (the protein's docking site). While erenumab's precise mechanism of action is not fully understood, experts know that CGRP is released from trigeminal nerve fibers during a migraine attack. Once released, CGRP is not only involved in the transmission of pain signals, but it also acts to dilate the blood vessels outside and inside the skull.

By having erenumab block CGRP's normal docking site, migraine attacks can be thwarted—and there is good data to support this theory.

In a phase 3 trial in the New England Journal of Medicine, over 900 participants with episodic migraine (defined as less than 15 migraines per month), were randomized to receive one of the following three therapies every month for six months:

  • A 70-mg subcutaneous (beneath the skin into your fatty issue) injection of erenumab
  • A 140-mg subcutaneous injection of erenumab
  • A placebo subcutaneous injection

The participants nor the investigators knew who was receiving erenumab versus the placebo injection, which is why this study is labeled as a double-blind study.


Results of the study revealed that the number of migraine days per month reduced by 3.2 days in the 70-mg treatment group and 3.7 days in the 140-mg treatment group, as compared with 1.8 days in the placebo group.

After a statistical analysis, the investigators determined that this result was significant. This means that the higher reduction in the treatment group was real (due to the effect of the drug) and not a random study error.

Results also revealed that about half of the participants receiving erenumab experienced a 50 percent or greater reduction in their average number of migraine days per month compared to about a quarter of those in the placebo group—again, this result was significant.

The treatment groups also had a significant reduction in the number of days they needed to use acute migraine medications, as compared to the placebo group.

Lastly, the participants in the study completed a scale called the Migraine Physical Function Impact Diary, of which a higher score indicates a greater migraine burden on functioning. Scores in physical-impairment and everyday-activities significantly improved for the treatment groups when compared to the placebo group.

Adverse Effects

The rates of adverse events were similar between the participants who received erenumab and the participants who received placebo, except for injection-site pain (those receiving erenumab experienced more). Overall, less than 3 percent of all the participants withdrew from the trial because of adverse effects.


These results suggest that erenumab is effective (in both doses) for preventing episodic migraine in some people. Erenumab also appears to have a good safety profile. This is welcoming news as current migraine-preventive medications are often discontinued due to undesirable side effects. This suggests that erenumab is well-tolerated.


Keep in mind that Erenumab, while a promising option for migraine prevention, is not a magic cure. For one, it does not work for everyone, as evidenced by the study.

Secondly, it is hard to say whether erenumab or other CGRP-targeted drugs in the pipeline will be effective options for people with refractory migraine, considering participants in the study were excluded if they had not responded to two prior classes of migraine preventive medications.

Thirdly, the studies examined only adults, so trials that examine children and teens with migraine are also needed.

Lastly, women in their childbearing years bear the grunt of the migraine burden, both in disease activity and intensity. Yet we do not know if erenumab is safe in pregnancy, as unlike many oral medications, erenumab would stay ina woman's system for weeks to months.

A Word From Verywell

The bottom line here is that these medications, which specifically target migraines (prior preventive medications were designed to treat other conditions, like seizures and depression), give hope and another option for people. They are not perfect, though, and do not work for everyone, supporting the mindset that a trial and error process is still needed when sorting out your preventive migraine plan.

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Article Sources
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