Anti-CGRP monoclonal antibodies in chronic migraine with medication overuse: real-life effectiveness and predictors of response at 6 months

Background In daily practice, anti-CGRP monoclonal antibodies (MAbs) may be useful in chronic migraine (CM) with medication overuse (MO), but data is limited. We evaluated their effectiveness in a real-life clinical cohort. Methods This is a prospective study conducted in CM patients with and without medication overuse treated with monthly MAbs during 6 months (erenumab/galcanezumab). We collected headache characteristics, including acute medication intake, through an electronic diary. We compared patients (1) with and without MO at baseline, (2) with and without ongoing MO after treatment, defining MO resolution as < 10 or 15 days/month of acute medication intake, according to analgesic type, during the 6-month treatment. Results Of 139 CM patients completing 6-month treatment with anti-CGRP MAbs, 71.2% (99/139) had MO at baseline. After 6 months, patients with and without MO at baseline had significant and similar proportions of >= 50% reduction in migraine days/month (MO: 63.6% vs. non-MO: 57.5%, p = 0.500). 60.6% (60/99) no longer satisfied MO definition. Reduction in headache frequency compared to baseline occurred in both MO-ongoing and MO-resolution group, although those who stopped overusing had a greater improvement (headache days/month: - 13.4 +/- 7.6 vs. -7.8 +/- 7.2, p < 0.0001). No differences in MO resolution were observed according to the MAbs used. Baseline lower pain severity was associated with MO resolution (OR [95%]:0.236[0.054-0.975]; p = 0.049). Conclusions In real-life anti-CGRP MAbs are as effective in CM patients with MO as in patients without it and facilitate MO cessation. Reduction in headache frequency and acute medication days/month occurs regardless of whether patients stop overusing or not.