Reduction in barbiturate prescription fills and quantity dispensed following initiation of rimegepant treatment: A real-world administrative claims study

Reduction in barbiturate prescription fills and quantity dispensed following initiation of rimegepant treatment: A real-world administrative claims study

Background: Butalbital carries a risk of abuse/physical dependence, has neurological side effects, and can increase the risk of Medication Overuse Headache (MOH).¹ Though acute treatment guidelines discourage the use of barbiturates for the acute treatment of migraine, butalbital and its combinations are still widely prescribed.^2,3 Effective, low-risk, novel abortive and preventive therapies with barbiturate-sparing characteristics have the potential to benefit patients with migraine.

Purpose/Objectives: This study evaluated real-world changes in barbiturate prescribing patterns and usage after initiation of migraine therapy with rimegepant, a calcitonin gene-related peptide antagonist, as measured by monthly quantity dispensed, monthly prescriptions filled, and discontinuation rate. 

Method: Prescription claims data were used to explore the association between initiation of therapy with rimegepant and barbiturate usage. Data from 9/15/2019 through 11/30/2022 were collected from a longitudinal pharmacy commercial claims database for 689,425 migraine patients treated with rimegepant. To determine study eligibility, we required at least 12 months of total time in the dataset, at least one barbiturate fill in a 6-month baseline period immediately prior to rimegepant initiation, and at least 2 rimegepant fills during follow-up. Monthly barbiturate prescription fill counts and barbiturate milligrams dispensed were tabulated in the 6-month baseline period and the 6-month follow-up. Discontinuation was defined as the absence of a barbiturate prescription fill after rimegepant initiation. For sensitivity analysis, the study was repeated with similar endpoints over 6 and 18 months of total observation and according to triptan use status.

Results: Overall, 34,486 migraine patients used butalbital ≤6 months prior to rimegepant initiation (age 46.8±12.6 years; 89.2% female). A total of 288,053 patients had 2+ rimegepant fills and met time-in-data requirements, but had no baseline butalbital fill, so the study cohort represents a 10.7% period-prevalence of barbiturate exposure in the 6-month period preceding rimegepant utilization. Decreases in mean monthly butalbital milligrams dispensed (-26.7%) and total butalbital Rx fills (-32.0%) were observed after rimegepant initiation.  A barbiturate discontinuation rate of 49.4% was observed after rimegepant initiation. Effects were similar for patients with or without triptan exposure over 6- and 18-month observation periods.

Conclusions: In migraine patients who use barbiturates, a significant decrease in barbiturate use, measured by mean monthly butalbital Rx fills, mean monthly butalbital milligrams dispensed, and butalbital discontinuation, was observed in the months following initiation of rimegepant therapy.

References: 1. Silberstein SD, et al. Headache. 2001;41:953-67.
2. Lipton RB, et al. Cephalalgia. 2020;40:437-47.
3. Huthcinson S, et al. Mayo Clin Proc. 2020;95:709-18,

Disclosure:
Noah L Rosen has served as a speaker for Allergan/Abbvie; served as an advisor for Biohaven, Eli Lilly, Lundbeck and Abbvie; is a section editor for Current Pain and Headache Reports; and is a board member of the American Headache Society. Ali Mohajer is an employee of Qral group, which received payment from Biohaven Pharmaceuticals during the conduct of this study. Lucy Abraham, Joshua Brown, Karin Hygge Blakeman, and Aaron Jenkins are full-time employee of, and own stock in, Pfizer. Linda Harris and Gilbert J L’Italien are full-time employees of, and own stock in, Biohaven.