Multiple testing of treatment‐effect‐modifying biomarkers in a randomized clinical trial with a survival endpoint

The recent revolution in genomics and the advent of targeted therapies have increased interest in biomarker‐defined subgroups of patients who respond to therapy or exhibit specific toxicities. Such biomarker‐defined subgroups are also being investigated for non‐targeted therapies (e.g. chemotherapy and statins). However, even when the targeting pathway has been identified, a broadly available test to identify the appropriate subgroup will rarely exist prior to the launch of the pivotal phase III trial.