Abstract 10315: The Effect of Protease-Activated Receptor-1 Inhibition With Vorapaxar in Post-mi and Nstemi Patients on Selected Biomarkers Reflecting Endothelial Function

Abstract

Introduction: Biomarker research related to protease-activated receptor-1 (PAR-1) inhibition with vorapaxar in humans has essentially focused on platelets. Follow-up (FU) time has been short, whereas in the current study, focus has been on endothelial function during both short- and long-term PAR-1 inhibition. Aim: To assess short- and long-term effects of vorapaxar (V) as compared to Placebo (PL) on the following biomarkers: Angiopoietin-2 (ANGPT2), Angiopoietin-like 4 (ANGPTL4), VEGF, ICAM-1, VCAM-1, E-Selectin (ESEL), von Willebrand Factor (VWF), Thrombomodulin (TM), PAI-1 and PAI-2. Methods: In an independent collective subproject performed in Norway, post-MI patients at steady state were recruited from the “Trial to Assess the Effects of Vorapaxar in Preventing Heart Attack and Stroke in Patients with Atherosclerosis” (TRA2ᵒP-TIMI 50) and NSTEMI patients were recruited from the “Thrombin Receptor Antagonist for Clinical Event Reduction in acute coronary syndrome” (TRACER) trial. Biomarkers were measured in duplicate by enzyme immunoassays (EIA) in citrated plasma at one month follow-up and at study completion (median 2.3 years) for subjects recruited from both trials. Results: Biomarkers were measured in 265 consecutive patients [age median 62.0 years (Q1-Q3: 55.0-68.0 years), males 83%] with at least one change from baseline value. Among these, biomarkers were available at both short- and long-term follow-up in 221 subjects. ANGPT2 increased significantly in V as compared to PL at 1-month follow-up in the total population (p=0.034), and in males in both post-MI (p=0.031) and NSTEMI subjects (p=0.012), respectively. ANGPTL4 increased (p=0.028) and PAI-2 decreased (p=0.025) significantly in the total population in favor of V at final FU. In the total post-MI subgroup and among males of that group, a short-term significant increase in ESEL in favor of V was observed, p=0.029 and p=0.018, respectively. Also, a transient significant increase in VWF (p=0.032) in favor of V was seen at one month in NSTEMI patients. Conclusions: Significant changes suggesting potential harmful effects in some biomarkers were observed during 1-month and long-term PAR-1 inhibition as compared to placebo in post-MI and acute coronary syndrome patients.