ABSTRACT
This chapter provides the definitions of key biomarkers used in drug development, the potential utility of the biomarkers in different stages of clinical trials and the current challenges and future directions. In order to properly use the biomarker data to inform the drug development, it is important to recognize not only the potential values of various biomarkers but also their limitations. Without predictive markers, agents such as Crizotinib and trastuzumab would be likely to fail in the clinical development. The rapid expansion of our knowledge about cancer genome and biology has provided hypothesis for an increasing number of potential therapeutic targets. Technical advancement in medicinal chemistry and biotechnology has also significantly enhanced the drug design for optimal potency and specificity against the intended targets. Proper use of biomarkers should start with a clear understanding of the nature and the intended use of various markers in clinical trials and treatment decisions.
