Definition of refractory migraine and their evolution

The term ‘refractory migraine’ (RM) is commonly used in clinical settings; however, it is not recognized in the International Classification of Headache Disorders, third edition. A growing need for a shared definition of refractoriness has been highlighted by a multidisciplinary expert group. Although definitions for RM currently exist, the key parameters for the definition of refractoriness (e.g., unresponsiveness to treatment, high frequency, severe disability, or all of these features) remain contentious. Thus, a consensus on the definition of RM is crucial.Calcitonin gene‐related peptide (CGRP) is a neuropeptide that plays an important role in migraine pathophysiology and is a target for migraine preventive therapies. Monoclonal antibodies targeting the CGRP (i.e., galcanezumab, fremanezumab, and eptinezumab) and its receptor (erenumab) have shown consistent efficacy for migraine prophylaxis with excellent safety profiles. Their effect on refractory cases has also been reported, offering promise to the many patients who have not found relief with existing treatments. Therefore, we anticipate a paradigm shift in migraine treatment.Following the widespread use of monoclonal antibodies targeting the CGRP and its receptor, the European Headache Federation proposed a definition for two subsets of difficult‐to‐treat migraine—resistant and refractory migraine—that considers both the frequency and disability caused by single and frequent attacks.We expect that this definition will help resolve previous conflicts that have limited the use of earlier definitions.