Dissemination of VMAT-2 Inhibitors: A New Class Drug for Tardive Dyskinesia and Huntington Disease

Abstract

Background and objectives: In 2017, the FDA approved deutetrabenazine (AUSTEDO) for the treatment of tardive dyskinesia (TD) and chorea associated with Huntington disease (HD). Concurrently, valbenazine (INGREZZA) was approved specifically for TD. The adoption of new medications is influenced by various factors, including patient's medical needs, the prescriber's adoption of new practice, and external environmental factors (e.g., cost). Our analysis aims to examine the dissemination of 2 vesicular monoamine transporter 2 (VMAT-2) inhibitors, deutetrabenazine and valbenazine, in the market.

Methods: In this cross-sectional study, we conducted a descriptive statistical analysis of the 2017-2020 prescription records for deutetrabenazine and valbenazine using the Centers for Medicare & Medicaid Services Medicare Provider Utilization and Payment Data: Part D Prescriber public use file. In addition, we linked this data set to the Open Payment database to analyze industry payments.

Results: We identified a total of 3,706 deutetrabenazine prescribers and 4,895 valbenazine prescribers. Prescription volume (standardized 30-day prescription) increased annually across different specialties for both VMAT-2 inhibitors from 2017 to 2020. Neurologists were the highest contributors to deutetrabenazine prescriptions (N = 50,017; 35.2%), and psychiatrists were the highest contributors to valbenazine prescriptions (N = 77,799; 42.3%). A total of 1,217 deutetrabenazine physician prescribers (47.5%) and 1,509 valbenazine physician prescribers (49.7%) received industry payments from TEVA Pharmaceuticals and Neurocrine Biosciences, respectively. Receipt of industry payments was associated with higher prescription volume for both deutetrabenazine (p < 0.001) and valbenazine (p < 0.001). Approximately three-quarters of the industry payments were used in nonconsulting services, with a median payment value per physician of $18,101 for deutetrabenazine and $25,920 for valbenazine.

Discussion: The findings illustrate a yearly increase in Medicare prescription volume for deutetrabenazine and valbenazine after FDA approval, with neurologists and psychiatrists as primary prescribers of deutetrabenazine and valbenazine, respectively. There was a statistical difference in the prescription volume between those who received industry payments and those who did not, suggesting that receipt of payments may be associated with prescription volume. Nonconsulting services constituted the largest sum of industry payments for both medications. Further research exploring the causative factors of new medication uptake is needed to better understand how medications disseminate across the market.