To evaluate the efficacy and safety of erenumab in patients with chronic migraine and medication overuse headache (CM-MOH).

Patients with migraine frequently use excessive medication, which increases their risk of developing chronic pain and headaches induced by medication. Erenumab is a monoclonal antibody that has been studied for its potential to prevent migraines and mitigate these issues by antagonizing the CGRP receptor.

We performed a systematic review and meta-analysis following PRISMA guidelines, retrieving data from PubMed, Embase, and Cochrane databases. Our primary endpoints were changes from baseline in acute headache medication days (AHMD) and monthly migraine days (MMD). Secondary outcomes included the incidence of adverse events, common adverse events, and the proportion of patients achieving a ≥50% reduction in MMD. A random-effects model was used to calculate the proportions with 95% confidence intervals (CIs). Statistical Analysis were performed using RStudio version 4.2.3.

Six randomized controlled trials were included, encompassing 875 patients, with a mean age of 42.7 years, treated with erenumab. Major reductions were observed in AHMD (RR 1.72; 95% CI: -2.81 to -0.62; p<0.01) and MMD (RR 1.88; 95% CI: -2.68 to -1.07; p<0.01). Although erenumab was associated with an increased risk of common adverse events, such as constipation (RR 1.43; 95% CI: 1.17 to 1.76; I²=14%), the overall incidence of adverse events was not statistically significant when compared to placebo (RR 1.02; 95% CI: 0.92 to 1.14; I²=57%). Additionally, a higher rate of patients achieved a 50% reduction in MMD after three months in the erenumab group (RR 1.49; 95% CI: 1.26 to 1.77; I²=22%). 

Erenumab may effectively reduce migraine frequency and medication use in CM-MOH patients with a manageable safety profile. It substantially improves the likelihood of achieving meaningful migraine relief, making it a valuable preventive option for this difficult-to-treat population.