This was a multicenter, randomized, double-blind, placebo-controlled, parallel-group trial. The trial consisted of four phases: screening (≤ 3 weeks of initial screening and a 4-week baseline phase); the double-blind treatment phase (24 weeks) in which participants received placebo or erenumab 70 mg or 140 mg daily; the active-treatment phase, in which participants underwent repeat randomization and were assigned to receive 70 mg or 140 mg of erenumab (28 weeks); and a safety follow-up phase (12 weeks).
