Adaptive designs and applications used in clinical trials

Aim: The objective of this study is to examine and investigate adaptive designs applied in clinical trials and to show the applications of some adaptive designs that are be ingused. Material and Method: In this study, several important classes of adaptive randomization designs and seamless Phase II/III adaptive trial designs are reviewed and recent developments in the literature on this topic are given. CRD design and RAR design were compared in terms of operational features with simulated data. In addition, four different seamless Phase II/III adaptive trial designs with a variable range of treatments were compared for response and contrast structures. Results: The RAR design has the same average power (87%), slightly lower median DA-efficiency (0.963 for RAR and 0.992 for CRD), and on average 5.4 more success compared to CRD. In seamless Phase II/III adaptive trial designs, when the contrast structure and responses tructure are the same, the group sequential design (96.5% and 95.8%, respectively) for the monotone and convexstructure, and the winners design for the step structure (83.3%) are observed to be powerful. Conclusion: Both CRD and RAR designs have been found to have a normal distribution of treatment assignment rates around target values, and we can say that the RAR design is more appropriate to use as it increases study success. For seamless Phase II/III adaptive trial designs, given the expected sample size, groups equential design has the most power if the response structure is known. This is because it allows early termination of the trial for more efficient design. When the response structure is unknown, drop–the-losers is the most powerful design, except where the response structure is "step". While all active dose levels have the same response rates, contrasts are not very important and therefore the use of adaptive design is not beneficial. Keywords: Adaptive Designs, Statistical Methods, Trial Simulation, Clinical Trials, Design Modification