Migraine/Headache

The advent of anti-CGRP medications is an example of translational research made real. Pioneering research by Drs. Lars Edvinsson and Peter Goadsby has yielded the monoclonal antibody therapeutics and will likely also result in the gepants. The availability of MABs represents a watershed moment in the treatment of migraine. These medications have specificity, as they were designed for primary migraine prevention. They work across a group of wide therapeutic targets, episodic migraine, chronic migraine, medication-overuse headache, and episodic cluster headache. They separate from placebo within 1 week, and often show clinical effects within a month or less. They have tolerability similar to placebo. There has been no significant or worrisome safety signal thus far in their use. They manifest unprecedented responder rates at ≥ 75% and even 100%. They lower all acute medication use and can convert patients from chronic migraine to episodic migraine and from acute medication overuse to non-overuse. They work in patients who have already had lack of success with at least 2-4 previous preventive medications. Pent-up demand for designer, well-tolerated, and effective migraine preventive medication in the USA has resulted in more than 100,000 individual patients prescribed erenumab from May to December of 2018, and the numbers continue to increase. The preventive treatment of migraine in the USA has shifted dramatically, and is likely to do so in the rest of the world as well.

Migraine is a prevalent, disabling neurological disorder involving the trigeminovascular system. Previous treatments were either originally intended for other conditions and/or associated with intolerable adverse effects. Calcitonin gene-related peptide (CGRP) is the most prevalent neuropeptide in the trigeminal afferent neurons and plays a significant role in pain sensitization central to migraine. The CGRP antagonists (gepants and monoclonal antibodies) are the first treatments created specifically for migraine, modulating pain signaling pathways and alleviating migraine attacks and recurrences. With their efficacy in several clinical trials and relatively fewer adverse effects, the CGRP antagonists show great promise for use in episodic migraine. This article is protected by copyright. All rights reserved.

In October 2014, the US Food and Drug Administration released a draft guidance for the development of drugs for the acute treatment of migraine. This guidance offered the option of replacing the previously required 4 co-primary endpoints: pain freedom, freedom from nausea, freedom from photophobia, and freedom from phonophobia, all at 2 hours posttreatment, with 2 co-primary endpoints: pain freedom and freedom from most bothersome symptom (MBS) other than pain, both at 2 hours posttreatment. At the time the new draft guidance was released, no large clinical trials had been undertaken with these 2 co-primary endpoints, posing a challenge in determining the sample size that might be required to achieve statistical significance. As a number of trials have now been completed, we conducted a review of the observed placebo responses, drug effect sizes, and sample sizes to better inform the design of future trials.