Utility and pitfals of dose ranging trials with multiple study objectives: fixed or adaptive
Seminar Room 1, Newton Institute
Multiple study objectives have been proposed in dose-ranging studies. Traditionally, a dose-response study is pursued as a fixed design of equal randomization ratio to each study arm and with only single study objective of detecting dose-response (DR). The PhRMA adaptive dose ranging working group has taken the ownership of the problem using an adaptive design or an adaptive analysis approach acknowledging the trial exploratory. The authors have critically pursued multiple study objectives via simulation studies (JBS 2007, SBR 2010) and concluded that achieving the first goal of detecting DR is much easier than achieving the fourth goal of estimating it, or the second and third goals of identifying the target dose to bring into the confirmatory phase. It is tempting to consider dose-ranging, dose-response and sometimes exposure-response studies as pivotal evidence, especially when they are designed as a two-stage adaptive trial. Design according to the study objective is vital to the success of the study. In this presentation, the utility and pitfalls of a two-stage adaptive dose-ranging trial will be elucidated. Challenges and reflection on some of the successful and not so successful regulatory examples will be highlighted. The appropriate stages distinguishing between learning stage versus confirmatory stage in a drug development program will also be discussed using some typical studies.