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For Clinicians What is the goal of the DAPT Study? What is the goal of the DAPT Study? The goal of the DAPT Study is to bring clarity to the global medical community regarding the benefits of 12 versus 30 months of dual antiplatelet therapy in preventing stent thrombosis and major adverse cardiovascular and cerebrovascular events (MACCE) in PCI patients treated with drug-eluting stents. back to top Please give an overview of the trial protocol? The DAPT Study will assess the safety and effectiveness of 12 versus 30 months of dual antiplatelet therapy for preventing stent thrombosis and major adverse cardiovascular and cerebrovascular events (MACCE) in subjects undergoing percutaneous coronary intervention (PCI) with drug-eluting stent placement for the treatment of coronary artery lesions. The trial will be a four-year, prospective, randomized, double-blind trial that is expected to enroll over 15,000 subjects being treated with a drug-eluting stent (DES) at over 200 sites in the U.S., E.U., Australia and New Zealand. A cohort of approximately 5,000 subjects treated with a bare metal stent (BMS) will also be enrolled. back to top Harvard Clinical Research Institute is the academic research organization that is responsible for the scientific management and independent analysis of the DAPT Study results. back to top What companies are participating in the DAPT Study? A group of drug-eluting stent and antiplatelet therapy manufacturers are collaborating with the Harvard Clinical Research Institute and providing funding for the DAPT Study (in alphabetical order): Abbott, Boston Scientific Corporation, Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership, Cordis Corporation, Eli Lilly and Company and Daiichi Sankyo Company Limited, and Medtronic, Inc. back to top Why is the DAPT Study important? There is currently a lack of data within the international scientific community investigating the use of dual antiplatelet therapy for over one year following a drug-eluting stent placement. As a result, considerable uncertainty exists about whether the duration of dual antiplatelet therapy in patients receiving drug-eluting stents should be 12 months (as per the ACC/AHA guidelines) or longer in patients without contraindication. To provide data to answer this critical public health question, the U.S. FDA has asked the manufacturers of U.S. FDA-approved DES to conduct a postmarket study to investigate whether patients should continue dual antiplatelet therapy for more than one year following drug-eluting stent implantation. back to top How many patients will be enrolled? The trial will be a four-year, prospective, randomized, double-blind trial that is expected to enroll over 15,000 subjects being treated with a drug-eluting stent (DES) at over 200 sites in the U.S., E.U., Australia and New Zealand. A cohort of approximately 5,000 subjects treated with a bare metal stent (BMS) will also be enrolled. back to top Where will the trial sites be located? There are expected to be over 200 sites in the U.S., Czech Republic, France, Germany, Hungary, Poland, Romania, United Kingdom, Australia and New Zealand that will participate in this study. A current listing of participating clinical sites is available at www.clinicaltrials.gov. back to top Is this trial being treated any differently in the E.U. as compared to the U.S.? U.S. FDA considers the DAPT Study to be a device study, due to the investigational nature of the duration of dual antiplatelet therapy (associated with the use of stents within and outside of their approved U.S. indications) and because the Study is designed to inform the U.S. labeling of DES regarding the duration of antiplatelet therapy. However, the regulatory authorities in Europe, Australia, and New Zealand consider the DAPT Study to be a drug study because guidelines specify treatment with thienopyridines post PCI for between 6 and 12 months following DES placement. Since randomization does not occur until 12 months PCI, which necessitates longer than standard treatment with thienopyridine, the gap between standard of care and the study design indicate this as a drug study. back to top How many patients will be treated with DES vs. BMS? Approximately 70% of subjects will receive DES. back to top How can my clinical site join the DAPT Study? Clinical sites that are interested in participating in the DAPT Study should contact Suzanne Morin - smorin@hcri.harvard.edu Phone: 617.632.1370, at the Harvard Clinical Research Institute. back to top When will the results from the study be available? The DAPT Study is expected to last over four years. Several milestones for enrollment and randomization will be met along the way, but the final results will be based on endpoints that occur after all subjects have been followed for the full treatment period. back to top How can I receive progress updates on how the study is going? The final DAPT Study results will be based on endpoints that occur after all subjects have been followed for the full treatment period which will be at least four years from the start of the trial in October 2009. Periodic updates and information regarding scientific presentations and publications from the DAPT Study investigators will be posted to the www.DAPTStudy.org website under News and Events. back to top Who is responsible for working with U.S. FDA? Harvard Clinical Research Institute (HCRI) is the sole holder of the DAPT Study’s Investigational Device Exemption (IDE). HCRI is working directly with the U.S. FDA Center for Devices and Radiological Health (CDRH). back to top How do the stent manufacturers’ post-market studies contribute to the DAPT Study? Due to the large sample size necessary for this study to detect small but clinically important differences, the FDA has allowed a limited amount of data to be contributed to the final DAPT Study analysis from several drug-eluting stent manufacturer-sponsored studies. The manufacturer-run studies have been designed to reproduce the DAPT Study randomization to 12 versus 30 months of therapy, and follow the same data collection, adjudication, and analytic processes as the DAPT Study. Several manufacturer-run studies have begun enrollment. The final analysis performed by the Harvard Clinical Research Institute will contain data from each of these sources to achieve overall enrollment of over 20,000 subjects. back to top Who will serve on the Data Monitoring Board (DMB), and what will their role be? Patient safety in the DAPT Study will be monitored throughout the trial by an independent Data Monitoring Board (DMB). The DMB is an independent group of physicians from the fields of cardiology and interventional cardiology and at least one biostatistician, who are not directly involved in the conduct of the DAPT Study. The DMB will review the study enrollment and subject safety (including reported serious adverse events) on a regular basis and will alert the U.S. FDA should a serious safety concern arise. Robert Bonow, M.D., Northwestern Memorial Hospital, Chicago, will chair the DMB. back to top What are the backgrounds of the principal investigators for the study? Laura Mauri, M.D., M.Sc. principal investigator The study is not designed to compare stents or drugs. The choice of stent or drug is not randomized, as the study is designed to determine in general practice, what is the optimal duration of therapy independent of stent or drug type. Given what we know about these products, which are all approved for use in the U.S., the differences between them are unlikely to be large enough to be detected even in a trial of this size. The DMB will monitor the safety of patients treated with various devices and drugs throughout the course of the study, should a significant safety concern arise, and the U.S. FDA will also have access to this information. If an unanticipated concern arose, this information would be disclosed. back to top Why is the use of bare metal stents included in this study? Isn’t the primary concern with DES? The primary concern of the DAPT Study is the optimal duration of dual anti-platelet therapy (DAPT) in subjects treated with drug eluting stents (DES), but there is also a valid clinical question as to whether the benefit (or lack of benefit) of the extended duration is unique to DES subjects or if it is also present (or absent) in bare-metal stent (BMS) subjects. The inclusion of BMS subjects in the randomization will allow DES to be compared with the alternative, BMS, after adjusting for duration of therapy and patient characteristics. back to top A number of studies examining optimal duration of dual antiplatelet therapy following drug-eluting stent placement are currently being conducted globally. Some randomized studies are examining the duration of 12 months versus of longer treatment, as is the DAPT Study. Some randomized studies are alternately examining the duration of 12 months versus a shorter treatment. While each of these studies adds complementary information, the DAPT Study is distinguished by its size and scope, and has sufficient power to compare both co-primary endpoints of stent thrombosis and clinical events.
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