Importance Patients with chronic migraine and medication overuse headaches (CM-MOH) represent a particularly burdened subpopulation. This trial provides first, to our knowledge, American Academy of Neurology class I evidence for a preventive therapy in CM-MOH.

Objective:

To assess erenumab efficacy and safety in patients with nonopioid CM-MOH. Design, Settings, and

Participants:

This randomized, double-blind, parallel-group, placebo-controlled trial took place at 67 centers in North America, Europe, and Australia from October 7, 2019, to November 2, 2022. This report reflects the primary analysis conducted in January 2023, using a database snapshot from December 1, 2022, which contains the complete dataset of the double-blind treatment period (DBTP). Participants included adults with CM-MOH who had 1 or more preventive treatment failure(s). There were 992 participants screened and 620 participants enrolled (584 in nonopioid cohort and 36 in opioid cohort).

Interventions:

Erenumab, 70 mg, 140 mg, or placebo, once monthly for 24 weeks. Main Outcomes and

Measures:

The primary end point was MOH remission at month 6. Secondary end points included change from baseline in mean monthly acute headache medication days (AHMD) at month 6 and sustained MOH remission throughout the DBTP. Safety end points were adverse events and changes in vital signs.

Results:

The primary analysis population included 584 participants in the nonopioid-treated cohort with a mean age of 44 years and 482 participants were female (82.5%). Baseline demographics and disease characteristics were balanced across groups. At month 6, 134 participants in the erenumab, 140 mg group (69.1%) (odds ratio [OR], 2.01; 95% CI, 1.33-3.05; P < .001 vs placebo) and 117 in the erenumab, 70 mg group (60.3%) (OR, 1.37; 95% CI, 0.92-2.05; P = .13 vs placebo) achieved MOH remission vs 102 participants in the placebo group (52.6%). AHMD use was also reduced in the erenumab groups vs placebo. Least squares mean (standard error) change from baseline in average monthly AHMD was -9.4 (0.4) days in the erenumab, 140 mg group (difference from placebo, -2.7; 95% CI, -3.9 to -1.6; P < .001) and -7.8 (0.4) days in the erenumab, 70 mg group (difference from placebo, -1.2; 95% CI, -2.4 to -0.1; P = .03), vs -6.6 (0.4) days in the placebo group. MOH remission throughout the DBTP was sustained in 119 participants (61.3%,) 96 participants (49.5%), and 73 participants (37.6%) in the erenumab, 140 mg, 70 mg, and placebo groups, respectively. Adverse events were consistent with the known safety profile of erenumab. Treatment-emergent adverse events incidence in the combined erenumab group was 66.8% (259 participants; constipation 15.2% (59 participants) and COVID-19 13.9% (54 participants) were most common. Conclusions and Relevance In this study, monthly, 140 mg, erenumab injections safely and effectively achieved MOH remission in patients with nonopioid CM-MOH within 6 months. Trial Registration ClinicalTrials.gov Identifier NCT03971071.