In Reply: We appreciate clarification by the investigators that they, rather than the sponsors, initiated the ENHANCE study. It is also clear that they considered this relatively small-scale surrogate end point study to be an important next step in the evaluation of ezetimibe when used in combination with simvastatin. Nonetheless, we continue to question the scientific value of the ENHANCE study given its completion well after drug approval.
As noted in another JAMA Commentary concerning the ENHANCE study,1 measures of subclinical atherosclerosis such as carotid IMT are more proximate than lipid levels to measures of health benefits such as cardiovascular events, but wall thickness is not the only determinant of cardiovascular events risk. Medication effects on IMT and clinical events could differ.1
Greenland P, Lloyd-Jones D. The ENHANCE Study and Marketing Ezetimibe—Reply. JAMA. 2008;299(23):2747-2748. doi:10.1001/jama.299.23.2747-b