Effectiveness and Safety of OnabotulinumtoxinA in Adolescent Patients with Chronic Migraine.

Chronic migraine (CM) significantly affects underage individuals. The study objectives are (1) to analyze the effectiveness and safety of onabotulinumtoxinA (BTX-A) in adolescents with CM; (2) to review the literature on BTX-A use in the pediatric population. This prospective observational study included patients under 18 years old with CM treated with BTX-A (PREEMPT protocol) as compassionate use. Demographic, efficacy (monthly headache days-MHD; monthly migraine days-MMD; acute medication days/month-AMDM) and side effect data were collected. A ≥ 50% reduction in MHD was considered as a response. Effectiveness and safety were analyzed at 6 and 12 months. A systematic review of the use of BTX-A in children/adolescents was conducted in July 2023. In total, 20 patients were included (median age 15 years [14.75-17], 70% (14/20) females). The median basal frequencies were 28.8 [20-28] MHD, 18 [10-28] MMD and 10 [7.5-21.2] AMDM. Compared with baseline, at 6 months (n = 20), 11 patients (55%) were responders, with a median reduction in MHD of -20 days/month (p = 0.001). At 12 months (n = 14), eight patients (57.1%) were responders, with a median reduction in MHD of -17.5 days/month (p = 0.002). No adverse effects were reported. The literature search showed similar results. Our data supports the concept that BTX-A is effective, well tolerated, and safe in adolescents with CM resistant to oral preventatives.