The use of onabotulinumtoxin A in migraine: mechanism of action, efficacy, safety and tolerability

Abstract

Migraine is a common, yet disabling, neurological disorder that is characterised by recurrent attacks of headache lasting 4–72 hours at a time. Headaches may also present with associated symptoms, such as nausea, vomiting, photophobia and/or phonophobia. There is a distinction between episodic migraine (EM) and chronic migraine (CM). Classed as a distinct clinical entity, patients with CM suffer from more headache days, increased headache disability, reduced health-related quality of life and greater co-morbidity than those with EM. CM is also considered a greater socioeconomic burden and associated with higher healthcare resource utilisation compared to EM. The main goal in CM treatment is to reduce the impact of migraine on the patient's life. Treatments combine lifestyle changes, trigger management and pharmacological management based on two aims: immediate treatment of acute migraine attacks and prophylactic treatment. Onabotulinumtoxin A is the only botulinum toxin licensed for the prevention of headaches in CM patients. The efficacy of injectable onabotulinumtoxin A for headache prevention in adults with CM was evaluated over 1 year in the phase 3 clinical trials of PREEMPT 1 and PREEMPT 2. A longer term study over a period of 2 years took place, and this phase 4 study was known as COMPEL. Good clinical evidence was found that treatment with onabotulinumtoxin A leads to a reduction of monthly headache days, as well as improvement in quality of life, and was both safe and well tolerated.