Evaluate long-term safety and clinical improvement with rimegepant in adults with frequent migraine.

Rimegepant is an orally administered small molecule CGRP receptor antagonist FDA-approved for acute treatment of migraine. While Phase 3 efficacy trials of rimegepant excluded subjects with ≥15 headache days/month, the rimegepant long-term safety study did not.

This was a multicenter, long-term, open-label safety study (NCT03266588) that included adults with a history of 2-14 monthly migraine attacks of moderate to severe intensity. Subjects with chronic migraine were allowed, and there were no limitations on the number of monthly migraine or non-migraine headache days subjects had prior to enrollment. The study included a 30-day observation period followed by a long-term treatment period in which subjects used rimegepant 75 mg orally up to once daily for up to 52 weeks. Migraine days were captured via electronic diary and reported as mild, moderate, or severe. This post-hoc subgroup analysis assessed safety and clinical global impression of change (CGI-C; 7-point rating scale) in subjects experiencing ≥15 migraine days of any severity per 30-days in the observation period.

Of the 1800 treated subjects, 246 (13.7%) experienced ≥15 migraine days per 30 days in the observation period. In this subgroup, the most common adverse events (AEs) were nasopharyngitis (8.5%), sinusitis (6.1%), and upper respiratory tract infection (5.3%). The rate of rimegepant discontinuation due to AEs was 4.9%. Serious AEs occurred in 3.7% of subjects; none were considered by the investigator to be related to rimegepant. Percentages (95% CI) of subjects who were considered improved since study entry on the CGI-C scale, were 89% (83.3, 93.2) and 87.5% (80.0, 92.5) at week 24 (n=157) and week 52 (n=112), respectively.

Long-term dosing of rimegepant 75 mg up to once daily in adults with frequent migraine was safe and well tolerated and associated with clinical improvement.