<qa>  What is another major limitation of the drug?The use of thienopyridines in patients undergoing percutaneous coronary intervention PCI has dramatically decreased the rate of early stent thrombosis. Further the CURE trial demonstrated that long-term clopidogrel decreases the rate of major adverse cardiovascular events in acute coronary syndrome patients ACS . However clopidogrel has several limitations including a long delay of action which is a potential limitation in acute settings of coronary artery disease. Another major limitation of the drug is the wide inter individual variability in clopidogrel responsiveness related to various factors. 