A Safety and Efficacy Study to Evaluate AMG 334 in Migraine Prevention

This is a Phase 2, randomized, double-blind, placebo-controlled study in participants with episodic migraine. The study's double blind treatment phase (DBTP) is designed to evaluate if treatment with erenumab once a month for 6 months compared with placebo is effective in reducing the mean monthly migraine days. Additionally, this study will continue to evaluate the efficacy and safety of erenumab during the OLTP where participants will continue to receive active treatment monthly. The study also includes a clinical home use (CHU) sub-study to assess a participant's ability to self-administer 140 mg of erenumab. Participants will be randomized 1:1 to use either 2 pre-filled 70 mg/mL autoinjector (AI)/pens or 1 pre-filled 140 mg/mL AI/pen. Participation in the substudy is optional, and no additional samples will be collected for the sub-study. After implementation of Protocol Amendment 2, the dose of erenumab in the OLTP increased from 70 mg to 140 mg QM. Participants who had already completed week 48 remain on 70 mg QM, participants not yet starting the OLTP, or not yet completing the week 48 visit receive erenumab 140 mg QM for the remainder of the OLTP.