This is a randomized, active-control, double-blind study of subjects with stabilized high-risk acute coronary syndrome (ACS). The primary objective is to evaluate the clinical benefit of Ezetimibe/Simvastatin Combination 10/40 (single tablet, under the brand VYTORIN in the United States) compared with Simvastatin 40 mg. As per the original protocol, if low-density lipoprotein cholesterol (LDL-C) response was inadequate, the dose of simvastatin in the VYTORIN arm or simvastatin arm, could be increased to 80 mg (Note: per June 2011 protocol amendment, criteria for continued use of 80 mg simvastatin were modified and new increases of simvastatin dose to 80 mg were stopped). Clinical benefit will be defined as the reduction in the risk of the occurrence of the composite endpoint of cardiovascular (CV) death, major coronary events, and stroke.
BACKGROUND: The IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) is evaluating the potential benefit for reduction in major cardiovascular (CV) events from the addition of ezetimibe versus placebo to 40 mg/d of simvastatin therapy in patients who present with acute coronary syndromes and have low-density lipoprotein cholesterol (LDL-C) ≤ 125 mg/dL.
METHODS: The primary composite end point is CV death, nonfatal myocardial infarction (MI), nonfatal stroke, rehospitalization for unstable angina (UA), and coronary revascularization (≥ 30 days postrandomization). The simvastatin monotherapy arm's LDL-C target is <70 mg/dL. Ezetimibe was assumed to further lower LDL-C by 15 mg/dL and produce an estimated ~8% to 9% treatment effect. The targeted number of events is 5,250.
RESULTS: We enrolled 18,144 patients with either ST-segment elevation MI (STEMI, n = 5,192) or UA/non-ST-segment elevation MI (UA/NSTEMI, n = 12,952) from October 2005 to July 2010. Western Europe (40%) and North America (38%) were the leading enrolling regions. The STEMI cohort was younger and had a higher percentage of patients naive to lipid-lowering treatment compared with the UA/NSTEMI cohort. The UA/NSTEMI group had a higher prevalence of diabetes, hypertension, and prior MI. Median LDL-C at entry was 100 mg/dL for STEMI and 93 mg/dL for UA/NSTEMI patients.
CONCLUSIONS: This trial is evaluating LDL-C lowering beyond previously targeted LDL-C levels. The results depend on achieving the desired separation of LDL-C with ezetimibe and on the assumption that ezetimibe's lowering of LDL-C will have similar event reduction efficacy as the LDL-C lowering from a statin. The results could affect future therapies and guidelines.
<b>BACKGROUND: </b>Statin therapy reduces low-density lipoprotein (LDL) cholesterol levels and the risk of cardiovascular events, but whether the addition of ezetimibe, a nonstatin drug that reduces intestinal cholesterol absorption, can reduce the rate of cardiovascular events further is not known.<b>METHODS: </b>We conducted a double-blind, randomized trial involving 18,144 patients who had been hospitalized for an acute coronary syndrome within the preceding 10 days and had LDL cholesterol levels of 50 to 100 mg per deciliter (1.3 to 2.6 mmol per liter) if they were receiving lipid-lowering therapy or 50 to 125 mg per deciliter (1.3 to 3.2 mmol per liter) if they were not receiving lipid-lowering therapy. The combination of simvastatin (40 mg) and ezetimibe (10 mg) (simvastatin-ezetimibe) was compared with simvastatin (40 mg) and placebo (simvastatin monotherapy). The primary end point was a composite of cardiovascular death, nonfatal myocardial infarction, unstable angina requiring rehospitalization, coronary revascularization (≥30 days after randomization), or nonfatal stroke. The median follow-up was 6 years.<b>RESULTS: </b>The median time-weighted average LDL cholesterol level during the study was 53.7 mg per deciliter (1.4 mmol per liter) in the simvastatin-ezetimibe group, as compared with 69.5 mg per deciliter (1.8 mmol per liter) in the simvastatin-monotherapy group (P<0.001). The Kaplan-Meier event rate for the primary end point at 7 years was 32.7% in the simvastatin-ezetimibe group, as compared with 34.7% in the simvastatin-monotherapy group (absolute risk difference, 2.0 percentage points; hazard ratio, 0.936; 95% confidence interval, 0.89 to 0.99; P=0.016). Rates of prespecified muscle, gallbladder, and hepatic adverse effects and cancer were similar in the two groups.<b>CONCLUSIONS: </b>When added to statin therapy, ezetimibe resulted in incremental lowering of LDL cholesterol levels and improved cardiovascular outcomes. Moreover, lowering LDL cholesterol to levels below previous targets provided additional benefit. (Funded by Merck; IMPROVE-IT ClinicalTrials.gov number, NCT00202878.).
This is a randomized, active-control, double-blind study of subjects with stabilized high-risk acute coronary syndrome (ACS). The primary objective is to evaluate the clinical benefit of Ezetimibe/Simvastatin Combination 10/40 (single tablet, under the brand VYTORIN in the United States) compared with Simvastatin 40 mg. As per the original protocol, if low-density lipoprotein cholesterol (LDL-C) response was inadequate, the dose of simvastatin in the VYTORIN arm or simvastatin arm, could be increased to 80 mg (Note: per June 2011 protocol amendment, criteria for continued use of 80 mg simvastatin were modified and new increases of simvastatin dose to 80 mg were stopped). Clinical benefit will be defined as the reduction in the risk of the occurrence of the composite endpoint of cardiovascular (CV) death, major coronary events, and stroke.
