Switching from clopidogrel to prasugrel to protect early invasive treatment in acute coronary syndromes : results of the switch over trial

Background: Clopidogrel is used to pretreat patients with non-ST elevation acute coronary syndromes (NSTE-ACS), but prasugrel provides better platelet inhibition with improved outcome. However, switching from clopidogrel at the time of percutaneous coronary intervention (PCI) remains incompletely defined. Our aim was to compare the pharmacodynamic (PD) effects of 3 prasugrel loading doses (LDs; G1:10 mg, G2: 30 mg, and G3: 60 mg) before PCI. A fourth group, continuing clopidogrel, served as control (G4). Methods: 100 clopidogrel-pretreated patients were enrolled and blood collected before PCI, 30 min, 1, 2, 4, 6, 24 and 48 h thereafter. Platelet inhibition was measured by vasodilator-stimulated phosphoprotein phosphorylation (VASP) and Verify-Now assays. The end-points (EP) was the difference of PD effect at 4 h between G3 and G4 (primary EP) with hierarchic evaluation between G2 and G1 versus G4 (secondary EP). A mixed-design ANOVA statistic was used to compare the four group scores over time. Results: Baseline characteristics were balanced across the groups. Only patients receiving 60 and 30 mg prasugrel LDs showed a rapid (< 1 h) and significant (p < 0.001) platelet inhibition up to 48 h after PCI·The primary EP was met by G3 (p < 0.0001), but also G2 scored different (p < 0–001) from G4 at 4 h after PCI. Similar findings were observed with Verify-Now. No differences in 30-day clinical outcomes were observed across groups. Conclusions: Switching NSTE-ACS patients before PCI to prasugrel 60 or 30 mg LDs determined a better and faster platelet inhibition than continuing clopidogrel, while PCI it is still underway.