Winner PK, et al. - As a postapproval commitment, researchers conducted this dose-ranging study investigating the efficacy and safety of onabotulinumtoxinA in adolescents. In this multicenter, double-blind, parallel-group, randomized trial, a single treatment of onabotulinumtoxinA (155 U or 74 U) vs placebo (intramuscular saline) was given via the recommended fixed-dose fixed-site paradigm in adolescents with chronic migraine (CM) aged 12 to < 18 years. They randomized 125 patients (onabotulinumtoxinA 155 U, n = 45; onabotulinumtoxinA 74 U, n = 43; placebo, n = 37). Change in frequency of headache days from baseline at week 12 was included as the primary efficacy measure; other measures were changed in the frequency of headache days at weeks 4 and 8 and change in frequency of severe headache days. All of these patients were included in the primary efficacy analysis; 115 (92.0%) patients completed the study. Although previous data demonstrated the benefits of onabotulinumtoxinA in adults with CM, the efficacy endpoints were not met in this study but onabotulinumtoxinA was well-tolerated in this adolescent population