The Vasodilator-Stimulated Phosphoprotein Assay as a Companion Test to Assess P2Y12 Receptor Activity in Clinical Studies

摘要

Background: Platelet Vasodilator Stimulated Phosphoprotein assay (Plt-VASP) is a whole blood flow cytometry assay for monitoring P2Y12 antagonists used in the management of acute coronary syndromes (ACS). The Thrombin Receptor Antagonist for Clinical Event Reduction (TRACER) trial evaluated vorapaxar compared to placebo in non-ST-elevation (NSTE)-ACS) patients. Methods: Blood samples for Plt-VASP assay were collected at the clinical sites and analyzed at a central laboratory. VASP phosphorylation induced by either prostaglandin E1 (PGE1) or PGE1+ADP was measured using flow cytometry and the platelet reactivity index (PRI) was calculated from the median fluorescence intensity (MFI) based on the following equation: PRI = [(MFI(PGE1)-MFI(PGE1+ADP))/MFI(PGE1)]M x 100 Plt-VASP assay results were analyzed in a total of 114 subjects in the placebo and 112 subjects in the vorapaxar group. Statistical analysis was performed by Friedman repeated measures analysis of variance (ANOVA) test using SAS version 9.1 software.