Objective: To assess efficacy and tolerability of 1-year erenumab treatment in patients with episodic migraine.

Methods: Patients were randomized (n=955; 1:1:1) during the 24-week double-blind treatment phase (DBTP) to monthly subcutaneous placebo, erenumab 70 or 140mg. At Week 24, 845 patients were re-randomized (1:1) to erenumab 70 or 140mg during the 28-week dose-blinded active-treatment phase (ATP). Monthly migraine days (MMD), achieving ≥50%, ≥75% and 100% reduction in MMD, and safety/tolerability were assessed.

Results: Mean MMD at DBTP baseline was 8.3. At Week 52, mean changes (SE) from pre-DBTP baseline/Week 24 (pre-ATP baseline) in MMD were −4.2 (0.2)/−1.1 (0.2) (70mg) and −4.6 (0.2)/−1.8 (0.2) (140mg) irrespective of treatment during the DBTP. For patients reducing dose from 140 (DBTP) to 70mg (ATP), change in MMD from Week 24 to 52 was −0.1 (0.3), and for those increasing from 70 (DBTP) to 140mg (ATP) was −1.8 (0.3). At Week 52, 61.0%, 38.5% and 19.8% of patients on erenumab 70mg, and 64.9%, 40.8% and 21.2% on erenumab 140mg, achieved ≥50%, ≥75% and 100% reduction in MMD from DBTP baseline, respectively. Among erenumab-treated patients in DBTP who showed ≥50% reduction in MMD during the last 3 months of DBTP and completed ATP, 86% showed sustained responses at ≥50% during the last 3 months of ATP. Safety of erenumab in the ATP was similar to the DBTP; exposure-adjusted incidence rates of adverse events were similar for either dose.

Conclusion: Over 52 weeks, erenumab provided sustained efficacy in episodic migraine; the safety profiles were similar between erenumab dose groups in the presence of dose blinding.