The mean bodyweight-normalized infant rimegepant dose was 0.0005 mg/kg/day, and the mean estimated relative infant dose was 0.51%, therefore indicating the study drug results in less than 1% relative infant dose in human milk.
Data from a phase 1 study published in Breastfeeding Medicine showed that excretion of rimegepant (Nurtec ODT; Biohaven) 75 mg into human milk was very low and the therapeutic was safe and well tolerated by lactating women. These results hold significance as more than 30 women in America are impacted by migraine and is the most common cause of disability among women of reproductive age (15-49 years).1-3
At the conclusion of the analysis, on weight-adjusted basis, the mean relative infant dose (RID) of Rimegepant was <1% of the maternal dose. Robert Croop, MD, chief development officer, Neurology, Biohaven, said in a statement that, "this is important data for women of reproductive age with migraine as it provides helpful new information for those who are lactating and wish to breastfeed their infants. Recognizing the lack of available data on migraine medications for breastfeeding women, Biohaven is proud to take a science-based approach by conducting a clinical study in this population."1
This open-label, single-center study included 12 women aged 18-40 years who were administered a single-dose of rimegepant 75 mg with a 36-hour follow-up. These patients had a gestation of 37-42 weeks and uncomplicated delivery of a single healthy child at least 2 weeks and less than 6 months before rimegepant administration. Investigators aimed to see whether Rimegepant is secreted in human milk after a single dose, as well as determine the concentration-time profiles of rimegepant in the human milk and plasma of health lactating women.
Rimegepant continued to show a consistent safety profile, represented by no adverse events (AEs), serious AEs, treatment-emergent AEs, or deaths reported in the analysis. No clinically meaningful abnormalities were observed in maternal vital signs, laboratory values, hematology results, chemistry results, or urinarlysis parameters. Notably, no subjects discontinued from the study due to AEs.2
At the conclusion of the analysis, the geometric mean milk to plasma concentration ratio was 0.20 (% coefficient of variation, 16.2) and the median was 0.20 (range, 0.16-0.27). Furthermore, the mean and median bodyweight-normalized infant doses were 0.005 mg/kg per day (SD, 0.001) and 0.005 mg/kg per day (range, 0.003-0.007), respectively. In comparison, the mean bodyweight-normalized maternal dose was 1.04 mg/kg per day (SD, 0.18), with a median of 1.09 mg/kg per day (range, 0.786-1.364). The mean RID was 0.51% (SD, 0.14) and the median RID was 0.462% (range, 0.358-0.773).
"I'm very pleased with the results of this clinical trial. Lactating mothers often end up having to choose between taking a migraine medication or breastfeeding their infant," Thomas W. Hale, PhD, professor of pediatrics and associate dean for research, Texas Tech University Health Sciences Center of Medicine, and study investigator, said in a statement.1 "Many of the questions we receive at the InfantRisk Center are about using migraine medications when breastfeeding. Now, with this research, we can share with lactating mothers that there is clinical data supporting a treatment option during breastfeeding."
The biggest strength of the study was that this was the first drug of the CGRP class to be examined in human milk, as well as the first evidence specific to rimegepant. In contrast, the limitations of the study include its small sample size and the absence of women with migraine, which may reduce the generalizability of the findings, the study investigators noted.
With its approved expanded indication in 2021, rimegepant became the first CGRP antagonist to be approved for prevention and the first to be approved for both acute and preventative therapy. The orally disintegrating anti-CGRP tablet was originally approved in a 75-mg dose for the acute treatment of migraine in February 2020—the first approval of the therapy for Biohaven.4