US approves first monoclonal antibody to prevent migraines

The first of a new class of drugs for prevention of headaches in adults has won approval by the US Food and Drug Administration.

Amgen’s monoclonal antibody Aimovig (erenumab) comes in a disposable auto injector for home use once a month. It blocks receptors to the protein fragment CGRP (calcitonin gene related peptide), which has been known for decades to be overproduced in people with chronic migraine. It will be available to patients by the end of this week, Amgen said.

In phase IIIb results presented last month at the American Academy of Neurology’s annual meeting erenumab cut the number of days with migraine by about half in chronic patients, defined as people experiencing at least 15 days of migraine a month.

Existing prophylactic treatments in migraine, such as topiramate, divalproex, and Botox, were all designed for other indications and carry a significant burden of adverse effects.

In trials erenumab was associated with a 2% discontinuation rate, but its arrival is making insurers queasy. Amgen announced a cost of $6900 (£5120; €5866) a year for the monthly injections—lower than some analysts had feared but still daunting when each patient’s treatment could last decades.

About 30 million US people report migraine headaches, while an estimated 2.8 million have chronic migraine with many days of headache each month.

The use of monoclonal antibodies, with their steep production costs, in the prophylaxis of an extremely common chronic disease is sure to raise overall health costs. Insurers have yet to say how and whether they will cover erenumab. Most health plans would be expected to cover an approved treatment for such debilitating symptoms, but not necessarily as first line therapy.

Three other CGRP blockers follow closely behind erenumab. FDA decisions are expected later this year on Eli Lilly’s galcanezumab and Teva Pharmaceuticals’ fremanezumab. Alder Pharmaceuticals’ eptinezumab has completed phase III trials but has not yet been filed for approval.

Galcanezumab has also produced positive results in a phase III trial in cluster headache. That study population saw no increase in adverse cardiac events, which provided added reassurance about safety, since people with cluster headache are at elevated risk of such outcomes.

But further study is required into the long term effects of the monoclonal antibodies. Post-market research into erenumab will include tracking women who become pregnant while taking it.

The non-profit Institute for Clinical and Economic Review analysed the likely costs and benefits of the new drug class on the basis of trial results and concluded that evidence supporting the use of erenumab was “insufficient” in patients with episodic or chronic migraine who had not yet tried other treatments. It was, however, likely to benefit those who had already tried other treatments, at a cost per quality adjusted life year (QALY) gained that is near commonly accepted limits.1

A review of the new drug class in JAMA this week described it as “progress, but not a panacea.”2

Novartis, which is developing erenumab for use in Europe, expects the European Medicines Agency to approve the drug in the next few months.