Assess the safety and tolerability of rimegepant 75 mg dosed every other day (EOD) for the preventive treatment of migraine and as-needed (PRN) for acute treatment on nonscheduled dosing days.

Rimegepant is an orally administered small molecule CGRP receptor antagonist indicated for the acute and preventive treatment of migraine.

This open-label extension phase of a 12-week, phase 2/3, randomized, double-blind, placebo-controlled study (NCT03732638) included adults aged ≥18 years with a history of 4-18 moderate to severe monthly migraine attacks. Subjects completing 12 weeks of double-blind treatment with rimegepant 75 mg or placebo EOD could continue with rimegepant 75 mg EOD for preventive treatment of migraine for 52 weeks. On nonscheduled dosing days, subjects could take rimegepant 75 mg up to once per day PRN for acute treatment of migraine. Subjects who took ≥1 dose of open-label rimegepant were analyzed. Months were defined as 4-week intervals.

Of the 741 subjects who received double-blind treatment, 603 (81.4% [rimegepant n=301, placebo n=302]) were treated in the open-label extension. The most common AEs were upper respiratory tract infection (7.1%), nasopharyngitis (6.3%), and back pain (4.3%). The rate of discontinuation due to AEs was 2.8%. Serious AEs in 2.2% of subjects were considered not related to rimegepant. Two deaths (0.3%), 1 due to aortic dissection related to Marfan syndrome and 1 due to sepsis, were also deemed unrelated to rimegepant. Aminotransferases >3x the upper limit of normal (ULN) occurred in 3.4% of subjects; none had concurrent elevations in bilirubin >2x ULN. Subjects took a mean (SD) of 14.6 (2.45) rimegepant doses per month; 81.4% used ≤16 rimegepant tablets per month.