October 6, 2009 – The Harvard Clinical Research Institute (HCRI) said last week the first patients are enrolled in the DAPT Study, marking the official initiation of the four-year clinical trial to investigate the duration of dual anti-platelet therapy (DAPT, the combination of aspirin and a thienopyridine/anti-platelet medication to reduce the risk of blood clots) following drug-eluting stent implantations.
The large-scale study is expected to bring clarity to the global medical community regarding the benefits of 12 versus 30 months of dual anti-platelet therapy in patients receiving drug-eluting stents to address coronary artery lesions. The first patients were enrolled into the DAPT Study by coprincipal investigator, Dean J. Kereiakes, M.D., medical director of The Christ Hospital Heart and Vascular Center and The Carl and Edyth Lindner Center for Research and Education at The Christ Hospital, Cincinnati, Ohio.
The DAPT Study will be conducted through a public-private collaboration involving HCRI, four major stent manufacturers: Abbott (XIENCE V), Boston Scientific (TAXUS PROMUS), Cordis Corp. (CYPHER), Medtronic Inc. (Endeavor); the manufacturers of thienopyridine/anti-platelet medications: Bristol-Myers Squibb Company/Sanofi Pharmaceuticals Partnership (Plavix - clopidogrel bisulfate) and Eli Lilly and Company and Daiichi-Sankyo Company Limited (Effient - prasugrel); and the U.S. Food and Drug Administration (FDA). HCRI, which is responsible for the scientific management of the DAPT Study and the independent analysis of the resulting data, received funding support from each of the drug and device manufacturers.
"This study is the first postmarket investigation in which the FDA brought together industry competitors who put aside competition and achieved an unprecedented level of cooperation with regulators and academia to answer a major public health question," said FDA Commissioner Margaret A. Hamburg, M.D.
Principal investigator, Laura Mauri, M.D., a cardiologist at the Brigham and Women's Hospital in Boston, Mass., and chief scientific officer of Harvard Clinical Research Institute said, "Current guidelines call for patients who are treated with drug-eluting stents to remain on blood-thinning medications for at least one year, but some physicians continue prescribing medications considerably longer in hopes of preventing very late stent thrombosis. The DAPT Study will enroll a broad spectrum of patients treated with stents and will look at both stent-related and patient-related outcomes to help define an appropriate course of therapy following placement of a drug-eluting stent."
"Drug-eluting stents are a widely accepted and generally safe treatment option for opening up a blocked artery. However, in rare instances, clots can form in the devices well past a year after they are implanted – after the currently recommended period of dual anti-platelet therapy use," said Dr. Kereiakes. "Because patients will be followed for almost three years for both stent-related and clinical outcomes, the DAPT Study results will be instrumental in establishing the standard of care following a drug-eluting stent procedure."
The DAPT (dual anti-platelet therapy) Study will assess the benefit of 12 versus 30 months of dual anti-platelet 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 international centers. A cohort of approximately 5,000 subjects treated with a bare metal stent (BMS) will also be enrolled. All subjects will receive 12 months of open-label thienopyridine/anti-platelet treatment in addition to aspirin. After 12 months, subjects who are free from all MACCE or major bleeding events will be randomized 1:1 to either placebo or ongoing dual anti-platelet therapy for an additional 18 months followed by three months of observational follow-up. Both arms will continue aspirin therapy. The choice of stent type and thienopyridine drug will be at the discretion of the patient and physician.
The coprimary endpoints for this trial are the incidence of the composite of all death, myocardial infarction (MI) and stroke (referred to as major adverse cerebral and cardiovascular events, or MACCE) between 12 and 33 months post-drug-eluting stent procedure and the incidence of stent thrombosis (ST) between 12 and 33 months post-stent procedure. The primary safety endpoint for this trial is incidence of major bleeding between 12 and 33 months post-drug-eluting stent procedure. The study will also include an adjusted comparison of patients treated with BMS compared with DES on varying durations of anti-platelet therapy.
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.
For more information: www.DAPTStudy.org, www.clinicaltrials.gov