Reassessing the validity of surrogate markers of drug efficacy in the treatment of coronary artery disease.

Surrogate markers of disease progression and drug efficacy have become an essential part of cardiovascular drug development. Some surrogate markers, such as LDL-cholesterol (LDL-C), have been studied extensively and are widely accepted as valid indicators of cardiovascular risk and as a basis for regulatory approval. Other markers, such as carotid intima-media thickness (IMT), can provide insights into coronary atherosclerosis, but their utility as surrogate endpoints remains uncertain. The ENHANCE clinical trial, which demonstrated robust, beneficial changes in LDL-C and other biochemical surrogate markers, but no reduction in carotid IMT, has highlighted the need to understand the use and contextual limitations of surrogate markers in guiding cardiovascular drug development and medical decision-making.