Use of Companion Diagnostics (CDx) and Predictive Biomarkers for Cancer Targeted Therapy: Clinical Applications in Precision Medicine

Abstract

In the field of oncology therapeutics, biomarker assays play an increasingly important role from discovery research to patient management. Companion Diagnostic (CDx) assays play an important role in precision medicine, having a specific clinical utility to aid in the identification of patients eligible to receive a therapeutic treatment, or to predict which patients may respnd to a targeted therapy. CDx assays may also affect the design of clinical trials, which can lead to higher patient response rates when the right patients are selected for treatment. CDx assays can also accelerate the introduction of new therapeutics, enabling a smaller number of patients to be enrolled in studies, reducing the number of patients exposed to investigational or approved therapeutics, thereby decreasing the chance of side effects. With the introduction of immuno-oncology drugs such as anti-PD-L1 and anti-PD-1 therapeutics, biomarker assays have become even more critically important in understanding the interactions between the tumor cells and immune response, and predicting patient responses. This chapter will review the history of CDx and present a high-level overview of the development path of CDx. It will also provide a survey of current FDA-approved or FDA-cleared CDx assays, examine some of the challenges in CDx development, and explore technologies and assay types applicable to CDx important in the next generation of oncology therapeutics.