Onabotulinumtoxin-A in Chronic Migraine: Should Timing and Definition of Non-Responder Status Be Revised? Suggestions From a Real-Life Italian Multicenter Experience.

A ≥30% reduction in headache frequency at T2 cut-off is not adequate in predicting a late response to treatment: more than a quarter of excluded patients would miss a clinical improvement with an ongoing treatment, while in a similar percentage of Responders the treatment would lose efficacy. Results from our real-life study suggest that we possibly have to postpone the definition of Responder/Non-Responder to OBT-A at least after 1 year of treatment (4 cycles).