A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study Comparing the Efficacy, Safety, and Tolerability of Subcutaneous Administration of Fremanezumab Versus Placebo for the Preventive Treatment of Chronic Migraine in Pediatric Patients 6 to 17 Years of Age Randomized, Double-Blind, Placebo-Controlled Study of Fremanezumab in Patients (6 to 17 Years) with Chronic Migraine A Study to Test if Fremanezumab is Effective in Preventing Chronic Migraine in Patients 6 to 17 Years of Age Efficacy, Safety, and Tolerability Study (Phase 3)