Testing the Efficacy of Eptinezumab 100 mg in the Early Prevention of Chronic Migraine over Weeks 1 to 4: Prospective Real-World Data from the GRASP Study Group

<b>Objectives</b>: This prospective, real-world study, designed by the Greek Research Alliance for Studying headache and Pain (GRASP), primarily aimed to examine whether a single administration of eptinezumab 100 mg can provide early therapeutic benefits over weeks 1-4 in preventing high-frequency chronic migraine (HFCM). <b>Methods</b>: We enrolled adults with HFCM (>23 monthly headache days-MHD) who had failed at least three preventive therapies and received a single infusion of 100 mg IV eptinezumab. Its efficacy was assessed using daily headache diaries over weeks 1-4 and at week 12, as well as with the Patients' Global Impression of Change (PGIC) scale at week 4. Primary outcomes included ≥50% reduction in monthly headache days (MHD) through week 4 and early response at week 1. Secondary outcomes included changes in migraine severity, acute medication use, and incidence of most bothersome symptoms (MBS) accompanying headache. <b>Results</b>: A total of 39 HFCM patients were analyzed. Their mean age was 48.1 years, and most were female. More than half (<i>n</i> = 22; 56%) were fast-responders, showing >50% reduction in MHD at week 1. Early 50% response rates at week 1 favored CGRP-naïve patients, compared to prior non-responders. Likewise, significant improvement was observed early across all other efficacy domains through week 4, with sustained benefits through month 3. MBS, like photophobia and nausea, decreased notably, while osmophobia and allodynia improved less over weeks 1-4, post-eptinezumab. At week 4, 64.1% of patients reported meaningful overall improvement on PGIC. <b>Conclusions</b>: Eptinezumab rapidly prevented HFCM with clinically meaningful benefits seen early at week 1. Patients experienced sustained improvement in all measured clinical domains through week 4 and onward to month 3.