The FDA has reported there was no significant difference in carotid artery thickness between patients taking Vytorin and patients taking Zocor, after a one-year review of the ENHANCE trial results.
On Jan. 25, 2008, the agency said that it would review data from the ENHANCE (Effect of Combination Ezetimibe and High-Dose Simvastatin vs. Simvastatin Alone on the Atherosclerotic Process in Patients with Heterozygous Familial Hypercholesterolemia) trial.
Following two years of treatment, carotid artery thickness (cIMT) increased by 0.011 mm in the Vytorin group and by 0.006 mm in the simvastatin group. The FDA said that the difference in the changes in carotid artery thickness between the two groups was not statistically significant. However, the decrease in levels of LDL cholesterol between the two groups was statistically significant---a 56 percent decrease in the Vytorin group versus a 39 percent decrease in the simvastatin group. The regulators said that the difference in the reductions in LDL cholesterol between the two groups was statistically significant.
The FDA said that results from ENHANCE do not change its position that an elevated LDL cholesterol is a risk factor for cardiovascular disease and that lowering LDL cholesterol reduces the risk for cardiovascular disease. Based on current available data, patients should not stop taking Vytorin or other cholesterol lowering medications and should talk to their doctor if they have any questions about Vytorin, Zetia, or the ENHANCE trial.
An ongoing trial, IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial), is examining whether treatment with Vytorin reduces the risk for cardiovascular events (composite endpoint of cardiovascular death, major coronary events and stroke), compared with simvastatin alone. This trial of 18,000 patients is scheduled to be completed in 2012.
Pending the results from IMPROVE-IT, the FDA has advised that patients should not stop taking Vytorin or other cholesterol lowering medications and should talk to their doctor if they have any questions about these medications.