Table 3.

Roles for biomarkers in clinical trials.

Application	Pros	Cons
Entry criteria (inclusion or exclusion)	Increases absolute differences and statistical power. Reduces harm in prevention trials	Limit target population. Could necessitate biomarker for use
– Enrichment	Exclude low-risk patients
– Narrow for effect	Exclude cases where drug cannot help (e.g., wrong etiology, injury already occurred). Also increases relative differences
Adjudication of end points
– Increase end point detection	Increases number of events in placebo arm. Increases absolute differences and statistical power	Increases number of events in treatment arm
– Improve adjudication accuracy	Increases likelihood of finding effect	Requires acceptance of the biomarker, influenced by marker accuracy