Response-adaptive designs in clinical trials for targeting the best treatment : An overview

Response-adaptive designs are increasingly being implemented in clinical trials, particularly early phase trials, and they have increasingly stimulated the work of researchers. This paper reviews a particular class of response-adaptive designs, which have a different property from the most adaptive designs in literature. These are response-adaptive designs targeting asymptotically the superior response, that is, treating with the superior treatment with prob- ability converging to one. The model underlying such designs is a randomly reinforced urn. In the context of clinical trials, this property is particularly attractive from an ethical point of view. This overview starts from the early paper of [8] until the recent work by [9].