ISAR-SAFE: Six vs. 12 Month DAT After DES Implantation

There is no significant difference in net clinical outcome between six months and 12 months of clopidogrel therapy after drug-eluting stent (DES) implantation, according to results of the ISAR-SAFE trial presented Nov. 16 at AHA 2014.

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For patients receiving aspirin, the optimal duration of clopidogrel therapy after DES implantation has remained largely unclear. In a multicenter, randomized, double-blind, placebo-controlled trial, Stefanie Schulz-Schüpke, MD, and her colleagues sought to find out whether six months of clopidogrel was non-inferior to 12 months in terms of clinical outcome in patients undergoing DES implantation. Six months after DES implantation, patients on clopidogrel were randomly assigned to either a six-month period of placebo or an additional six-month period of clopidogrel.

Due to slow recruitment and low events rates the trial was prematurely stopped after enrolling 4,005 of 6,000 planned patients. Of the 4,000 included in the final analysis, 1,997 received six months of clopidogrel and 2,003 received 12 months of clopidogrel. The study’s primary endpoint – a composite of death, myocardial infarction, stent thrombosis, stroke, and thrombolysis in myocardial infarction (TIMI) major bleeding at nine months after randomization – occurred in 29 patients (1.5 percent) assigned to six months of clopidogrel and 32 patients (1.6 percent) assigned to 12 months of clopidogrel. Stent thrombosis was observed in five patients (0.3 percent) assigned to six months of clopidogrel and three patients (0.2 percent) assigned to 12 months of clopidogrel. TIMI major bleeding was observed in four patients (0.2 percent) assigned to six months of clopidogrel and five patients (0.3 percent) to 12 months of treatment.

Despite their results, the investigators conclude that their findings “must be considered in view of its premature termination and lower than expected event rates.”


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