Erenumab is a human monoclonal antibody indicated for migraine prophylaxis in adults. This new medication potently and specifically competes with calcitonin gene-related peptide (CGRP) to inhibit its activity at the CGRP receptor. CGRP is a potent vasodilator of peripheral and cerebral blood vessels. It is also thought to be involved in other pathogenic pathways responsible for migraines, including the release of inflammatory mediators from mast cells and transmission of nociceptive messages in the central nervous system. Furthermore, serum CGRP concentrations have been shown to rise during migraines and other neurovascular headache episodes, and then return to normal upon headache resolution.
A double-blind placebo-controlled trial investigated the efficacy of erenumab 70mg and 140mg in patients with a baseline of 8.3 migraine days per month. By months four to six of the trial, the number of migraine days per month was reduced by 3.2 and 3.7 in the erenumab groups and 1.8 in the placebo group. The secondary endpoint of at least 50% reduction in the mean number of migraine days per month was achieved in 43.3% and 50.0% of the erenumab patients and 26.6% of the placebo group. The incidence and severity of adverse events, including serious adverse events and events requiring discontinuation, was similar for the erenumab and placebo groups.
Erenumab is presented as a pre-filled pen for subcutaneous injection once every four weeks. Suitable injection sites are the abdomen, thigh, and upper arm. Sites should be rotated to minimise injection site reactions. The safety and efficacy of erenumab have not been formally studied in patients taking other migraine prophylactic agents or patients who experience fewer than fourmigraine days per month.
- Aimovig® (erenumab) Australian approved product information. Macquarie Park: Novartis. Approved July 2018.
- Goadsby PJ, Reuter U, Hallström Y, Broessner G, Bonner JH, Zhang F, et al. A controlled trial of erenumab for episodic migraine. N Engl J Med. 2017; 377: 2123-32.
- Russo AF. Calcitonin gene-related peptide (CGRP): a new target for migraine. Annu Rev Pharmacol Toxicol. 2015; 55: 553-52.