Introduction: Vorapaxar is a once daily oral protease-activated receptor-1 (PAR-1) antagonist for the reduction of thrombotic events in patients with a history of myocardial infarction or peripheral arterial disease. Efficacy and safety was evaluated in a large randomized clinical trial (TRA 2°P TIMI 50), with a median follow-up of 30 months. This is the first descriptive study of vorapaxar treatment patterns in routine clinical practice.
Objectives: To evaluate medication adherence and persistence among vorapaxar new users.
Methods: Vorapaxar new users ≥18 years of age were identified with an index prescription date between June 2014 and October 2015 with ≥1 years of follow-up through October 2016. The qualifying prescription was identified from Symphony Health’s US outpatient pharmacy claims linked to private practitioner claims and hospital data. Baseline characteristics were assessed using a 1-year look-back prior to the index prescription date. Adherence was defined as a medication possession ratio (MPR) ≥80%, and persistence was defined allowing for up to a 7-day gap in days supply. Sensitivity analysis with 15-day gap to define persistence was performed.
Results: The 529 vorapaxar new users included in the analysis were predominantly male (67%), 11% African American and 70% Caucasian, and had a mean (SD) age of 65.2 (10.5) years. At the end of 3, 6, and 12 months, 61%, 45%, and 32%, respectively, of new users were adherent on vorapaxar. A majority (68%) of vorapaxar users were persistent at 3 months, 48% at 6 months, and 29% at 12 months. An additional 10% restarted therapy by the end of the first year after a period of supply interruption. Results of the sensitivity analysis for persistence using 15-day allowable gap were within 1-2% of primary analysis. The median (IQR) time to discontinuation of therapy during the first year was 2.6 (1.2-6.1) months. During the first year, a median (IQR) of 5 (3-9) prescriptions per patient were filled- majority 30 day fills.
Conclusions: Medication adherence and persistence of use decreased over time. One-third of patients were adherent and/or persistent at one year. Further research is warranted to understand treatment pattern differences by indication of use and factors affecting adherence and discontinuation.