The safety and efficacy of onabotulinumtoxinA for CM was demonstrated in the pivotal phase III Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) trial. In this trial, patients were treated every 12 weeks whether or not their headaches had returned to baseline levels and the primary outcome period was after two treatment cycles. At baseline, these patients had more than 19 headache days, and after two treatment cycles, their headaches had been reduced by 8 to 9 days per 28 days. The responder rate analysis of the study population shows that about 25% of patients improved by 75% in terms of a reduction of migraine days. In my practice, I usually do three cycles 12 weeks apart, and only if there is no change in headache frequency after this, do I change treatments. In the pivotal trials, the first statistical separation from placebo occurred in the first 4 weeks. There is a small subgroup of patients who fail to respond to the first two treatments and only start to respond after the third treatment.4-10
Do not receive BOTOX® Cosmetic if you: are allergic to any of the ingredients in BOTOX® Cosmetic (see Medication Guide for ingredients); had an allergic reaction to any other botulinum toxin product such as Myobloc® (rimabotulinumtoxinB), Dysport® (abobotulinumtoxinA), or Xeomin® (incobotulinumtoxinA); have a skin infection at the planned injection site.