Treatment with erenumab decreased the number of monthly migraine days in patients with chronic migraine and had a safety profile comparable to placebo. Findings support erenumab as a possible therapy for migraine prophylaxis.

• Phase 2, randomized, double-blind, placebo-controlled, multicenter study in adults with chronic migraine
• 667 adults aged 18–65 years enrolled from centers in North America and Europe from April 3, 2014 to December 4, 2015
• Chronic migraine define as ≥15 headache days per month, of which ≥8 were migraine days
• Patients randomized (3:2:2) to subcutaneous placebo, erenumab 70mg or erenumab 140mg given every 4 weeks for 12 weeks
• Primary endpoint: change in monthly migraine days from baseline to last 4 weeks of double-blind treatment (Weeks 9–12)
• Safety endpoints: adverse events, clinical laboratory values, vitals, anti-erenumab antibodies

• Of 667 adults randomized to treatment, 637 completed treatment
• Both erenumab 70mg and 140mg doses reduced monthly migraine days vs. placebo (-6.6 days vs. -4.2 days, difference -2.5 days, 95% CI: -3.5 to -1.4; P<0.0001)
• Adverse events reported in 39% of placebo group, 44% of erenumab 70mg group, and 47% of erenumab 140mg group
• Most common adverse events were injection-site pain, upper respiratory tract infection, and nausea
• Patients in the erenumab 70mg group (n=11) and 140mg group (n=3) had anti-erenumab binding antibodies but none were anti-erenumab neutralizing antibodies
• 4 withdrawals due to adverse events reported
• No clinically significant abnormalities in vital signs, lab results, or electrocardiogram findings seen
• More research needed to assess long-term safety and efficacy of erenumab as well as its real-world applications