ABSTRACT
In this chapter, we discuss the biomarker-informed design using the two-
level biomarker model proposed by Wang and Chang (2014). We have
discussed the pick-the-winner designs where the same endpoint is used for
both the interim and final analyses of the study. However, the benefits of
such a design or method could be limited if it takes very long to obtain
the primary endpoint measurements at the interim. For example, in oncol-
ogy trials, it usually takes 12-24 months to observe overall survival-the
most commonly used and preferred regulatory primary endpoint. The long
time needed to reach the interim analyses can present potential operational
challenges and may delay bringing a drug to the market.
