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Study Shows Enoxaparin Is as Effective as Unfractionated Heparin in Patients With Non-ST-Elevation Acute Coronary Syndromes
“The results of previous trials provide strong evidence of the superiority of enoxaparin over unfractionated heparin in medically managed ACS patients,” said Robert Califf, MD, Associate Vice Chancellor for Clinical Research, Director, Duke Clinical Research Institute at Duke University Medical Center, Durham, NC, and a lead investigator of the trial. “Now, data from SYNERGY demonstrate benefit with enoxaparin in aggressive management of this high-risk population as well. Physicians should not hesitate to transition patients to percutaneous coronary intervention while on enoxaparin.”
In this patient population, Lovenox was established to be at least as effective as UFH in the reduction in the incidence of death or myocardial infarction at 30 days, the primary endpoint (14.0 percent vs. 14.5 percent, p= NS).
Safety in SYNERGY was assessed by GUSTO and TIMI major bleeding criteria, rate of transfusions, intracranial hemorrhage (ICH) and bleeding causing hemodynamic instability. Results showed that the incidence of GUSTO severe bleeding was 2.9% with Lovenox® vs. 2.4% for UFH (p=NS). Incidence of TIMI non-CABG major bleeding was 2.4% versus 1.7% (p= 0.025), a statistically significant difference. Incidence of bleeding was confounded by extensive anticoagulant switching. Importantly, there was no difference observed in the incidence of blood transfusions, ICH and abrupt closure.
Patients Started and Continued on Lovenox® Had Better Outcomes
A secondary analysis of 5,637 patients enrolled in SYNERGY showed that those who began treatment with Lovenox® prior to randomization and continued on it throughout the course of therapy experienced an 18 percent relative risk reduction in the incidence of death and myocardial infarction at 30 days vs. patients who were started and continued on UFH (12.8% vs. 15.6%, p=0.0029).
“Based on these outcomes, enoxaparin would appear to be a preferred first-line therapy. These findings suggest that switching anticoagulant agents during an episode of ACS, including in the cath lab, provides no clinical benefit and increases bleeding complications,” said James J. Ferguson, MD, Associate Director of Cardiology Research at the Texas Heart Institute at St. Luke’s Episcopal Hospital in Houston, TX, and a lead investigator of the study.
A meta-analysis of all ACS trials comparing Lovenox to UFH, in a broad spectrum of patients ranging from conservatively to invasively managed, shows that Lovenox significantly reduces the incidence of death and MI, with no significant increase in bleeding complications.
SYNERGY Trial Design
The SYNERGY (Superior Yield of the New Strategy of Enoxaparin, Revascularization & GlYcoprotein IIb/IIIa Inhibitors) trial was a prospective, randomized, open-label study evaluating the efficacy and safety of Lovenox® versus UFH in high-risk patients presenting with non-ST-elevation ACS and treated with an early invasive strategy. SYNERGY was conducted at approximately 400 investigative sites in the United States, Canada, Europe and South America. It is the largest trial ever conducted in unstable angina and non-ST elevation myocardial infarction (UA/NSTEMI). All patients enrolled in the study received treatment with Lovenox® or UFH and concomitant therapy with oral and intravenous antiplatelet agents.
“These findings show that patients receiving enoxaparin throughout the course of therapy experienced significantly better outcomes compared to UFH,” said Dr. Califf. “Given the wealth of prior data showing its benefits in the management of ACS patients, its newly demonstrated favorable profile in early invasive patient management, and convenience of use, enoxaparin can be considered an anticoagulant of choice in ACS.”
About Acute Coronary Syndromes
Acute coronary syndromes involve the formation of blood clots in the vessels that supply blood to the heart, resulting in the reduction of blood flow to the heart. These conditions include unstable angina, non-Q-wave or non-ST-elevation myocardial infarctions, and acute myocardial infarction (AMI), or heart attack. According to the American Heart Association, more than 12 million Americans alive today have a history of coronary heart disease (myocardial infarction, angina pectoris or both).
Acute coronary syndromes are commonly treated with a combination of anticoagulant medications. Very often, percutaneous coronary intervention (PCI), such as angioplasty, may be necessary in these patients. While UFH traditionally has been used to reduce the risk of blood clots, studies such as the ESSENCE trial have demonstrated the superiority of Lovenox® to unfractionated heparin in managing UA/NSTEMI.
Low-molecular-weight heparins prevent the formation of a blood clot by inhibiting thrombin, an enzyme present throughout the circulation system. Antiplatelet drugs are effective in preventing blood clotting by inhibiting the aggregation of platelets. PCI describes a procedure used to dilate narrowed arteries to facilitate blood flow in which a balloon catheter with or without a stent is introduced into the blocked artery and inflated to widen its diameter, allowing more blood to flow through.