What's a migraine day? Analysis of the variety in the definition of a migraine day across phase III trials with drugs targeting the CGRP pathway.

BackgroundAlthough guidelines for clinical trials have proposed a definition for a migraine day, randomised clinical trials tend to vary in their definition used.MethodsDefinitions of a migraine day in phase III trials with monoclonal antibodies and small molecules targeting the calcitonin gene-related peptide pathway for the preventive treatment of migraine were compared.ResultsTwelve different definitions were found across 23 trials. Variation in headache duration, the inclusion or exclusion of probable migraine and the inclusion or exclusion of a treated migraine attack with a specific or non-specific drug were most subject to debate. No single criterium or set of criteria was common to all definitions used. The most common single criterium used was a minimal headache duration of at least 30 minutes where only two clinical trials allowed for a headache with a shorter duration to be included.ConclusionThere is a pressing need for a standardised accepted definition of a migraine day both from a clinical and research perspective.