TOKYO and INDIANAPOLIS, June 2 /PRNewswire/ --
-- Universal Definition of Myocardial Infarction provided jointly by leading international cardiology societies
Investigators from the Phase III TRITON-TIMI 38 study applied the new classification system for the Universal Definition of Myocardial Infarction to the results of the study and showed that patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) taking prasugrel, as compared with clopidogrel (Plavix(R)/Iscover(R)), experienced reduced risk of heart attack regardless of heart attack type (procedural related or spontaneous), size or timing over a 15-month period. The new Universal Definition of Myocardial Infarction(1) was developed in 2007 by the Joint European Society of Cardiology, American College of Cardiology, American Heart Association and the World Heart Federation Task Force. This post hoc analysis was published in Circulation on June 2, 2009.(2)
In this post hoc analysis, the incidence of non-procedural heart attack in patients treated with prasugrel compared with clopidogrel was 2.8 percent vs. 3.7 percent, respectively (p=0.0013). The risk of procedure-related heart attacks was 4.9 percent in patients who took prasugrel compared with 6.4 percent of patients who took clopidogrel (p=0.0002). Non-procedure-related heart attacks included spontaneous heart attacks, which could be differentiated from procedure-related heart attacks that were associated with the artery-opening procedure known as PCI, or with stent thrombosis.
The analysis reported in this paper was not pre-specified in the TRITON-TIMI 38 study as the Universal Definition of Myocardial Infarction was published after the trial started.
"Our findings provide a more complete characterization of the effect of prasugrel on new or recurrent heart attacks," said David A. Morrow, M.D. M.P.H., Associate Professor of Medicine at Harvard Medical School and a Senior Investigator with the TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA.
Investigators classified 1,218 heart attacks that occurred during the TRITON-TIMI 38 study based on the Universal Definition of Myocardial Infarction. This definition includes a new classification system to characterize different types of heart attacks based on the size and type of heart attack.(3) The types of heart attacks evaluated in this study, according to the definition, included:
- Type 1: Spontaneous heart attack caused by a primary coronary
event, such as a plaque rupture in a coronary artery with less blood
then flowing to the muscle
- Type 2: Secondary heart attack due to either increased oxygen
demand or decreased supply due to other conditions such as spasm of the
coronary artery or low blood oxygen from anemia
- Type 3: Sudden cardiac death with evidence of a heart attack
- Type 4: Heart attacks related to a PCI
- Type 4a: Heart attacks associated with a PCI procedure
- Type 4b: Heart attacks associated with stent thrombosis as
documented by an angiography or at autopsy
- Type 5: Heart attack associated with coronary artery bypass graft
(CABG)
The investigators examined the size and timing of a new heart attack, as well as whether or not the heart attack was associated with an elevation of the ST segment on the electrocardiogram (noted as STEMI and NSTEMI).
The results of the analysis showed:
- The rate of spontaneous heart attacks (Type 1) was 2.5
percent in patients taking prasugrel compared with 3.4 percent of those
taking clopidogrel (p=0.0015).
- The incidence of PCI-related heart attacks (Type 4) was 4.8
percent in prasugrel patients compared with 6.4 percent in clopidogrel
patients (p=0.0002).
- The majority of spontaneous heart attacks occurred after 30 days
of treatment, and the risk of non-procedural heart attack during
maintenance dosing through the entire 15 months of the study was 2.3
percent in patients taking prasugrel versus 3.1 percent in patients
taking clopidogrel (p=0.0069).
- Treatment with prasugrel reduced new and recurrent STEMI heart
attacks, a high-risk form of heart attack, (1.0 percent vs. 2.1 percent,
p<0.0001) and NSTEMI heart attacks (6.5 percent vs. 7.9 percent,
p=0.0024) compared with clopidogrel.
- In the TRITON-TIMI 38 trial, there was an increased risk of major
bleeding with prasugrel compared with clopidogrel (2.4 percent vs. 1.8
percent), which included life-threatening and fatal bleeding.(4)
About TRITON-TIMI 38
The main TRITON-TIMI 38 clinical trial, previously published in the New England Journal of Medicine in November 2007 (Vol. 357 No.20), compared prasugrel with clopidogrel in patients with ACS undergoing PCI.
About Acute Coronary Syndrome
Coronary heart disease, which can result in ACS, is the single most common cause of death in the European Union, accounting for more than 741,000 deaths in the EU each year.(5) Acute coronary syndrome (ACS), which includes heart attack and unstable angina (chest pain), affects more than 1.4 million people in the United States annually.(6) Coronary artery disease occurs when the arteries become narrowed or clogged by cholesterol and fat deposits and cannot supply enough blood to the heart. In some cases, a blood clot may partially or totally block the blood supply to the heart resulting in ACS.(7) Many ACS patients are managed with PCI, which usually includes a stent placement.
About Prasugrel
On February 25, 2009, the European Commission granted marketing authorization for EFIENT(R) (prasugrel) for the prevention of atherothrombotic events in patients with ACS undergoing percutaneous coronary intervention. Prasugrel works by inhibiting platelet activation and subsequent aggregation by blocking the P2Y12 adenosine diphosphate (ADP) receptor on the platelet surface. Antiplatelet agents prevent platelets from clumping or sticking together, which can result in clogged arteries and may lead to heart attack.
Among other things, prasugrel is contra-indicated in patients with a history of stroke or transient ischaemic attack.
About Daiichi Sankyo
A global pharmaceutical innovator, Daiichi Sankyo Company, Ltd., was established in 2005 through the merger of two leading Japanese pharmaceutical companies. This integration created a more robust organization that allows for continuous development of novel drugs that enrich the quality of life for patients around the world. Areas of central focus for Daiichi Sankyo research and development are thrombotic disorders, malignant neoplasm, diabetes mellitus, and autoimmune disorders. Equally important to the company are hypertension, hyperlipidemia or atherosclerosis and bacterial infections. For more information, visit www.daiichisankyo.com.
About Eli Lilly and Company
Lilly, a leading innovation-driven corporation, is developing a growing portfolio of pharmaceutical products by applying the latest research from its own worldwide laboratories and from collaborations with eminent scientific organizations. Headquartered in Indianapolis, Ind., Lilly provides answers - through medicines and information - for some of the world's most urgent medical needs.
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