ACC Statement on ENHANCE Trial
January 15, 2008
The ENHANCE (Effect of Combination Ezetimibe and High-Dose Simvastatin vs. Simvastatin Alone on the Atherosclerotic Process in Patients with Heterozygous Familial Hypercholesterolemia) trial results were released by Merck and Schering-Plough Pharmaceuticals on January 14, 2008. The results of the trial show no benefit from the combination of ezetimibe (Zetia) and simvastatin (sold together as Vytorin) over simvastatin alone in terms of affecting the rate of atherosclerosis progression.
The study involved 720 patients with heterozygous familial hypercholesterolemia and showed no significant difference in the primary endpoint between patients treated with ezetimibe and simvastatin versus patients treated with simvastatin alone over a two-year period. The study was designed to prove that Vytorin could slow the growth of plaque in carotid arteries supplying the brain more than simvastatin alone. Media reports indicate that the results of the trial show no benefit from the combination of ezetimibe (Zetia) and simvastatin (sold together as Vytorin) over simvastatin alone.
The American College of Cardiology recommends that major clinical decisions not be made on the basis of the ENHANCE study alone.
According to the American College of Cardiology (ACC), this study deserves serious thought and follow-up. The overall incidence rates of cardiac events were nearly identical between both treatment groups, and both medicines were generally well tolerated. There should no be reason for patients to panic. The difference in IMT changes between the simvastatin group and the Vytorin group was 0.006 mm vs. 0.011 mm.
Health care professionals should speak to their concerned patients using this drug. The ACC is also releasing a public statement explaining that this is not an urgent situation and patients should never stop taking any prescribed medications without first discussing the issue with their health care professional. Further research will be needed in this area to provide conclusive evidence about which lipid lowering strategy is preferred (statin alone vs. statin plus ezetimibe).
Furthermore, the ACC notes that this trial is an imaging study and not a clinical-outcome study. Conclusions should not be made until the three large clinical-outcome trials are presented within the next two to three years. The ACC recommends that Zetia remain a reasonable option for patients who are currently on a high dose statin but have not reached their goal. The ACC also notes that Zetia is a reasonable option for patients who cannot tolerate statins or can only tolerate a low dose statin.
Reports also indicate that the ENHANCE trial has been submitted as an abstract to be presented at the upcoming American College of Cardiology Scientific Session in March, 2008. The late-breaking clinical trial selections by the meeting co-chairs are scheduled to occur in late January.
For more information on the ENHANCE trial, please visit Cardiosource at http://www.cardiosource.com/clinicaltrials/trial.asp?trialID=1640.