Efficacy and Safety of Erenumab in Adults With Medication Overuse Headache: Final Results From a Phase 4 Randomized Placebo‐Controlled Study

ABSTRACT Background Erenumab‐induced medication overuse headache (MOH) remission in participants with chronic migraine (CM) in a prospective, Phase 4, randomized, placebo‐controlled trial with an open‐label treatment period (OLTP). We present 1‐year results from the combined double‐blind treatment period (DBTP) and OLTP for the stratified nonopioid cohort. Methods Participants with CM‐MOH were randomized 1:1:1 to subcutaneous 70 or 140 mg erenumab every 4 weeks (QM) or placebo for the initial 24 weeks (DBTP). Those successfully completing DBTP could continue the 28‐week OLTP, maintaining the same erenumab dose received during DBTP or, if receiving placebo, randomly assigned 1:1 to erenumab 70 or 140 mg QM. OLTP endpoints were exploratory. Results Overall, 552 participants received erenumab (70 mg, n = 274; 140 mg, n = 278); 95.3% completed OLTP. One‐year MOH relapse in participants who achieved MOH remission at DBTP Month 6 was 2.7% (3/111) and 2.4% (3/124) with erenumab 70 and 140 mg, respectively; absence of MOH at study end was observed in 69.0% (189/274) and 75.5% (210/278) of participants. Sustained MOH absence over 1 year was reported in 60.5% (107/177) and 68.8% (119/173) of participants, respectively. Sustained improvements in measures of headache days, medication days, and function were observed in both groups. No new safety concerns were identified (grade ≥ 3, 35 6.3%; serious, 17 3.1%; adverse events leading to treatment discontinuation, 5 0.9%). Conclusions Erenumab was effective in inducing and sustaining MOH remission and improving function over 1 year. Treatment compliance remained high, with safety events consistent with erenumab's known safety profile. Trial Registration NCT03971071