OnabotulinumtoxinA in Chronic Migraine: A Profile of Its Use.

OnabotulinumtoxinA (Botox; a formulation of botulinum toxin type A (BoNT/A)] is indicated for the prevention of headaches in adults with chronic migraine (CM) in numerous countries, including those of Europe. In clinical trials, intramuscular administration of BoNT/A (155-195 units at 12-week intervals) to patients with CM was generally well tolerated and associated with sustained and clinically meaningful improvements in multiple assessments of headache symptoms, headache-related impact and/or disability and migraine-specific health-related quality of life over a period of 1 year (in the pivotal PREEMPT 1 and 2 studies) and 2 years (in the phase IV COMPEL study). The efficacy and safety of BoNT/A therapy have been confirmed in a number of large, prospective, real-world studies conducted in Europe, including the 2-year REPOSE study. Intramuscular BoNT/A has also demonstrated greater clinical utility than the oral prophylactic medication topiramate in a clinical practice setting (FORWARD study).