The role of statistics in the design and analysis of companion diagnostic (CDx) studies

Companion diagnostic tests are crucial in the development of precision medicine. These tests provide information that is essential for the safe and effective use of specific therapeutic products. Statistics plays a key role in the design and analysis of studies to demonstrate the safety and effectiveness of the companion diagnostics. This article can serve as an introduction to companion diagnostics for therapeutic statisticians and for diagnostic ones as well as a discussion of some of the statistical challenges. The topics include biomarker development, diagnostic performance, misclassification, prospective-retrospective validation, bridging studies, missing data, follow-on diagnostics and complex signatures.