Hamilton, ON (September 5, 2005) -- A Canadian-led study involvingresearchers from 41 countries has demonstrated in the world's largeststudy of acute coronary syndromes (ACS) that a new anti-thrombotictherapy is safer and as effective as the traditional therapy used inpreventing heart attacks, death and ischemia in people with seriousheart conditions.
The OASIS-5/MICHELANGELO study, presented today at the EuropeanSociety of Cardiology meeting in Stockholm, Sweden, showed thatfondaparinux, a new anti-thrombotic therapy, was as effective asenoxaparin in preventing heart attacks, death and ischemia (reductionin blood supply to the tissues) at nine days after an event butdemonstrated a dramatic reduction in major bleeding. The studyindicated patients had a lower mortality rate at the one-month markafter an acute coronary event. This finding remained consistentthroughout the following six months of follow-up.
These favourable effects resulted in a clear net benefit infavour of fondaparinux throughout the study, said Dr. Salim Yusuf,principal investigator and chair of the international study.
"The study findings demonstrate that fondaparinux is likely theanti-thrombotic drug of choice in patients with acute coronarysyndromes who are already receiving aspirin and clopidogrel," said Dr.Yusuf, professor of medicine in the Michael G. DeGroote School ofMedicine at McMaster University and director of the Population HealthResearch Institute, McMaster University and Hamilton Health Sciences inHamilton, Ontario, Canada. "This is the first study in ACS patientsthat demonstrates that effective prevention of thrombotic events can becombined with a safer drug profile."
The OASIS-5/MICHELANGELO study was a multi-centre, randomized,double-blind, placebo-controlled trial involving more than 20,000patients and was conducted at 576 sites in 41 countries. The primaryobjective was to evaluate the efficacy and safety of fondaparinux, asynthetic drug that acts specifically during the earlier part of theclotting cascade, with enoxaparin, a low molecular weight heparin thatis commonly used as an anti-thrombotic therapy.
Previous studies have indicated that patients who experience amajor bleed in acute coronary syndromes exhibit a much higher risk ofdeath during the immediate weeks following the event. Anti-thrombotictherapies used in the last two decades have substantially decreased therisk of a heart attack but have also been associated with a significantincrease in bleeding risks. Therefore, therapies that maintain thebenefits of currently available anti-thrombotic therapies, but haveless bleeding, are of great clinical importance, Dr. Yusuf said.
Dr. Shamir R. Mehta, project director of the internationalstudy, associate professor of medicine in the Michael G. DeGrooteSchool of Medicine at McMaster University and an interventionalcardiologist at Hamilton Health Sciences, remarked: "The fact that thebenefits and safety of fondaparinux are observed on top of othereffective treatments, such as aspirin, clopidogrel, GP IIb/IIIainhibitors and revascularization procedures, emphasizes its value in abroad spectrum of patients with acute coronary syndromes."
Dr. Mehta added: "One of the most important findings of the trial wasthat fondaparinux was associated with a lower overall mortality at sixmonths compared with enoxaparin. This is good news for patients in thatdoctors now have a therapy that will not only saves lives but is alsosubstantially safer than current treatments."
Professor Keith Fox, professor of cardiology at the Universityof Edinburgh and co-chair of the study's operation committee, added:"This study demonstrates that improving the safety of therapy leads toenhanced long-term survival for patients."
Dr. Yusuf noted that previous studies showed that fondaparinuxwas superior in preventing deep venous thrombosis when compared toenoxaparin. "The current findings extend the beneficial results fromthe venous side to high-risk individuals with atherothrombosis," headded.
The OASIS-5/MICHELANGELO study was supported by grants fromSanofi-Synthelabo, Organon, and Glaxo-Smith Kline. The OASIS network isled by researchers in the Population Health Research Institute,McMaster University and Hamilton Health Sciences and is aninternational collaboration of investigators who have completed some ofthe largest and most influential trials in heart disease that havecontributed to enhanced patient care worldwide.
The Canadian Cardiovascular Collaboration Office is located atthe Population Health Research Institute, McMaster University andHamilton Health Sciences and is one of Canada's leading researchinstitutions. The experts at this institution are recognizedinternationally for their leading edge research, innovation, andexcellence in cardiovascular sciences and thrombosis.
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