Long‐term efficacy and safety of erenumab in patients with chronic migraine in whom prior preventive treatments had failed: A subgroup analysis

To assess the long‐term efficacy and safety of erenumab in the subgroup of patients with chronic migraine (CM) in whom prior preventive treatments had failed (TF) (≥1, ≥2, and ≥3 TF medication categories) and never failed (preventive naïve or prior preventive treatments had not failed), using the data from a 52‐week, open‐label treatment period (OLTP) of the parent study.