Background: Clinical and cost-effectiveness of prasugrel vs. clopidogrel in acute coronary syndrome (ACS) was only evaluated using TRITON-TIMI 38 event rates. A comparative analysis of both drugs in contemporary European ACS patients is lacking. Methods: To address this issue, cardiac and bleeding events of 2 "sister" multicenter stent trials, BASKET-PROVE (BP) I with clopidogrel and BPII with prasugrel (for 12 months each) were used in a hybrid analysis. Medication costs were 2015 sales prices, event costs modelled for Denmark (DNK), Germany (GER) and Switzerland (SUI) and quality adjusted life years (QALY) by EQ-5D-3L questionnaire. Results: In BPI and II, 1012 and 985 ACS-patients received drug eluting stents, respectively, followed-up for 2 years. Compared to clopidogrel, prasugrel-treated patients had no more major cardiac events (5.2% vs. 6.4%, p=0.422) nor cardiac deaths (1.6% vs. 1.0%, p=0.255), but more major bleedings (4.0% vs. 1.7%, p < 0.001) and altogether no difference in QALYs (-0.027 (95% CI: -0.064/0.011)). Prasugrel caused higher total expenditures per patient: 1116.3 (DNK), 1063.5 (GER) and 880.8 (SUI) EURO, respectively. Accordingly, incremental cost-effectiveness was negative for prasugrel vs. clopidogrel with ratios of -45,907 (DNK), -39,909 (GER) and -33,435 (SUI) EURO/QALY gained, making clopidogrel an economically dominant strategy, even after accounting for the non-randomized comparison. Conclusion: Findings of this contemporary European ACS-cohort showed markedly lower cardiac event rates than TRITON-TIMI 38 and no significant difference in 2-year QALYs between prasugrel and clopidogrel-treated patients. At current drug prices, clopidogrel use resulted in an economically dominant treatment strategy in Western European patients. (C) 2017 Elsevier B.V. All rights reserved.