Challenges in drug and biomarker co-development.

Co-development of drugs and biomarkers should be considered when the biomarker is intricately related to the use of the drug. There are risks and benefits to co-development and these need to be considered carefully early in the process. The current chapter attempts to delineate when it is appropriate to plan for co-development and to discuss a range of issues. Challenges include the determination of the type of assay (laboratory-developed test vs. reference laboratory vs. kit), the designs of trials for evaluation of clinical utility, and the regulatory pathway. Successful co-development requires planning very early in the process and assembling the appropriate multi-disciplinary team.