Expression biomarkers for clinical efficacy and outcome prediction in cancer.

Progress in cancer treatment has been slow, and the outlook for curing cancer is only marginally different from the situation a decade ago. Paradoxically, although the pharmaceutical industry has stepped up costly discovery research and drug development, approvals are on the decline and pipelines are dwindling. In an effort to reduce the number of drug failures and curtail burgeoning R&D costs, drug companies are exploring the use of biomarkers to evaluate toxicity and efficacy earlier in the development process. Biomarkers hold promise for optimization in dosing, adverse event prediction, efficacy evaluation, lead prioritization, and mechanism-of-action profiling of drug candidates. Furthermore, clinicians can use biomarkers to monitor patient response in clinical trials. In this perspective article, the authors explore the applications of cancer-related expression biomarkers in drug discovery and discuss how this will impact the industry and benefit the patient.