Erenumab for the preventive treatment of chronic migraine complicated with medication overuse headache: an observational, retrospective, 12-month real-life study

Background Erenumab is a monoclonal antibody blocking the calcitonin gene-related peptide receptor, which has been approved for the preventive treatment of chronic migraine (CM). The aim of this study was to explore the safety and effectiveness of erenumab in patients suffering from CM and medication overuse headache (MOH) in a real-life setting, up to 1 year. Methods Data regarding 81 patients treated with erenumab were retrospectively analyzed. Every 3 months, the following variables were collected: the mean number of headache days per month (headache index (HI)), the average number of painkillers taken per month (analgesic consumption (AC)), the mean number of days with painkiller consumption (number of days on medication (NDM)), the headache intensity (numeric rating scale (NRS) score), the 6-item Headache Impact Test (HIT-6), and the Self-Reported Instrument to Assess Work-Related Difficulties in Patients With Migraine (HEADWORK) scores. Results The HI, AC, and NDM and the NRS, HIT-6, and HEADWORK scores were significantly lower at every time point from the 3rd month onward compared to baseline (all P < 0.0001). No significant differences were found between patients who underwent painkiller detoxification before starting erenumab and those who did not (all P > 0.05). No significant differences were found between patients taking erenumab in combination with other preventive treatments and the ones taking it alone (all P >= 0.05). Five patients dropped out because of adverse events, which resolved after stopping erenumab. Conclusion Erenumab was safe and effective for CM complicated with MOH. Painkiller withdrawal and the association with other preventive treatment(s) seem useless.