Cardiovascular biomarkers and surrogate end points: key initiatives and clinical trial challenges.

Biomarkers have proven to be critical tools in both cardiovascular clinical practice and clinical research. In clinical practice, biomarkers are used to identify patients at risk for disease, stratify disease severity, guide intervention decisions and monitor patient response to therapy. Biomarkers are also used extensively to improve the design of cardiovascular clinical trials, identify 'at-risk' populations, allow for preliminary screening for response, identify appropriate dose ranges, study subgroup differences and identify early safety concerns. The purpose of this paper is to describe current key cardiovascular biomarker initiatives and to outline some of the important considerations in applying these biomarkers in a clinical trial setting, utilizing the examples of HDL cholesterol, HDL-targeted therapies and imaging tools used to assess HDL-targeted therapies as a case study.