The Effect of Protease-Activated Receptor-1 (PAR-1) Inhibition on Endothelial-Related Biomarkers in Patients with Coronary Artery Disease.

BACKGROUND:  Vorapaxar has been shown to reduce cardiovascular mortality in post-myocardial infarction (MI) patients. Pharmacodynamic biomarker research related to protease-activated receptor-1 (PAR-1) inhibition with vorapaxar in humans has short follow-up (FU) duration and is mainly focused on platelets rather than endothelial cells. AIM:  This article assesses systemic changes in endothelial-related biomarkers during vorapaxar treatment compared with placebo at 30 days' FU and beyond, in patients with coronary heart disease. METHODS:  Local substudy patients in Norway were included consecutively from two randomized controlled trials; post-MI subjects from TRA2P-TIMI 50 and non-ST-segment elevation MI (NSTEMI) patients from TRACER. Aliquots of citrated blood were stored at -80°C. Angiopoietin-2, angiopoietin-like 4, vascular endothelial growth factor, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, von Willebrand factor, thrombomodulin, and plasminogen activator inhibitor-1 and -2 were measured at 1-month FU and at study completion (median 2.3 years for pooled patients). RESULTS:  A total of 265 consecutive patients (age median 62.0, males 83%) were included. Biomarkers were available at both FUs in 221 subjects. In the total population, angiopoietin-2 increased in patients on vorapaxar as compared with placebo at 1-month FU (p = 0.034). Angiopoietin-like 4 increased (p = 0.028) and plasminogen activator inhibitor-2 decreased (p = 0.025) in favor of vorapaxar at final FU. In post-MI subjects, a short-term increase in E-selectin favoring vorapaxar was observed, p = 0.029. Also, a short-term increase in von Willebrand factor (p = 0.032) favoring vorapaxar was noted in NSTEMI patients. CONCLUSION:  Significant endothelial biomarker changes during PAR-1 inhibition were observed in post-MI and NSTEMI patients.