This study made rimegepant available, before regulatory approval, to subjects who completed a rimegepant clinical trial and whom investigators deemed to be unsatisfactorily treated with then-available migraine treatments and likely to benefit from continued treatment with rimegepant.

Rimegepant, an orally administered small-molecule calcitonin gene-related peptide (CGRP) receptor antagonist, was approved by the FDA for acute and preventive treatment of migraine based on positive efficacy and safety data from multiple clinical trials.

This open-label expanded access protocol (NCT03934086) included adults aged ≥18 years who completed any clinical trial of rimegepant for acute treatment of migraine. After a screening phase (1-14 days), subjects were assessed at baseline (Day 1), monthly visits for the first 3 months, and visits every 2 months thereafter. Oral rimegepant 75 mg was provided to treat migraine attacks of mild, moderate, or severe pain intensity up to once per calendar day. Safety outcome measures included adverse events (AEs), laboratory assessments (hematology, serum chemistry, and liver function tests), and vital signs.

Eighty-seven subjects were screened, and 77 subjects were treated. Most treated subjects (84%) came from a prior long-term, open-label safety study of rimegepant and were female (96.1%) and White (84.4%); mean±SD age was 43.7±12.2 years. Mean±SD time of rimegepant treatment was 20.6±11.6 weeks, and median rimegepant exposure per 4 weeks was 6.4 doses. Most AEs were of mild to moderate intensity, with the most common being nasopharyngitis (7 [9.1%]), influenza (6 [7.8%]), and sinusitis (5 [6.5%]). All AEs were considered not related to rimegepant, and no subjects were discontinued due to an AE. There were no serious AEs and no elevations of alanine aminotransferase or aspartate aminotransferase greater than 3x the upper limit of normal.

Results from the completed expanded access protocol confirmed the favorable safety and tolerability profiles of oral rimegepant observed in previous studies.