PHILADELPHIA – “Erenumab was well tolerated and safe, with no safety signals detected over this period,” said , professor of neurology at the University of Copenhagen. Dr. Ashina presented the interim data from a 5-year, open-label extension study of erenumab at the annual meeting of the American Headache Society.
Erenumab is a monoclonal antibody that targets and blocks the calcitonin gene-related peptide (CGRP) receptor. In May 2018, the Food and Drug Administration approved erenumab for the preventive treatment of migraine in adults. The treatment, marketed as Aimovig, is administered once monthly by self-injection.
During the open-label study, patients initially received 70 mg of erenumab monthly. After approximately 2 years, patients switched to 140 mg of erenumab monthly. The researchers’ interim efficacy analysis included all patients on 140 mg of erenumab with data about monthly migraine days after more than 4 years of treatment. The safety analysis included all patients who enrolled in the open-label treatment period and received at least one dose of erenumab.
Of 250 patients who increased the erenumab dose from 70 mg to 140 mg, a total of 221 (88%) completed the open-label treatment period or remained on 140 mg after more than 4 years. Patients’ average number of monthly migraine days at study baseline was 8.7, and the average change from baseline to the most recent month in the interim analysis was –5.8.
During the most recent month of assessment, 77% of patients had at least a 50% reduction in monthly migraine days from baseline, 56% had at least a 75% reduction, and 33% had a 100% reduction.
Mean change from baseline in acute migraine‐specific medication treatment days was –4.6, from a baseline of 6.1.
Among the 383 patients who entered the open-label treatment period and received at least one dose of erenumab (mean age, 41.3; 79% female), the median erenumab exposure was 58.5 months. The exposure‐adjusted incidence of adverse events per 100 patient‐years was 124.9, and the three most frequent adverse events (per 100 patient-years) were nasopharyngitis (10.9), upper respiratory tract infection (6.8), and influenza (4.7). The exposure‐adjusted incidence rate per 100 patient‐years for constipation was 1.3 (9/383) for 70-mg erenumab and 2.6 (15/250) for 140-mg erenumab.
“The exposure‐adjusted incidence rate per 100 patient‐years of serious adverse events was 3.8, similar to the rate observed for erenumab and placebo during the placebo‐controlled periods of studies,” the researchers said.
The study was sponsored by Amgen, and several study authors are employees of Amgen or Novartis, the companies that market erenumab. Dr. Ashina is a consultant for Amgen, Novartis, and other companies.
SOURCE: Ashina M et al. AHS 2019, Abstract IOR10.