Study of Early MIDAS Reduction at 3 Months as Predictor of Long-term Erenumab Treatment in Chronic Migraine: a Real-life, Open-label, Trial

Monoclonal antibodies directed against the Calcitonin Gene Related Peptide (CGRP-mAbs) pathway are a silver lining in the setting of migraine therapies, partly overcoming the issues related to poor effectiveness and tolerability of previous preventive treatments.

These drugs act on the CGRP pathway, a key vasoactive neuropeptide in migraine pathophysiology involved in activation and sensitization of afferent trigeminal nociceptors of the trigeminovascular system. Galcanezumab, fremanezumab and eptinezumab target the CGRP ligand, while erenumab, a fully human IgG2, targets its receptor. mAbs efficacy and safety have been largely documented in multiple randomized clinical trials, open-label studies as well as in the real-world setting.

The Italian Medicines Agency (AIFA) approved a 12-month period of mAbs treatment reimbursement through the National Health Service for migraine patients with the following features: i) at least 8 migraine days per month in the last three months, ii) a MIgraine Disability ASsessment (MIDAS) score ≥ 11, and iii) previous failure for inefficacy or no tolerability of at least three preventive drugs, among β-blockers, tricyclic antidepressants, antiepileptics, and onabotulinumtoxin-A for chronic migraine (CM).

In addition, a reduction of at least 50% of MIDAS score after 3 and 6 months of treatment is the only mandatory step to continue beyond these check-points. Thus, MIDAS score is pivotal for mAbs treatment initiation and continuation. MIDAS is a self-administered five-item questionnaire focusing on reduction in home and workplace productivity, and a score > 11 identify a set of patients with a moderate to severe disability. A MIDAS score reduction during mAbs treatment was demonstrated in the short and long term period, but its role as predictor of mAbs clinical outcome has never been consistently studied. A major concern for using a single parameter as a mandatory criterion for prescription and continuation of a preventive treatment is the limited ability to capture the multifaced disability that characterize the migraine spectrum. On the other side, reduction in monthly migraine days (MMDs) represents a pivotal outcome for clinical trials and physicians, but this may not completely highlight the patients' perspective.

The investigators consecutively screened migraine patients attending the outpatient clinic of the Headache Science & Neurorehabilitation Center of the IRCCS Mondino Foundation (Pavia, Italy).