1. Introduction

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In the traditional paradigm of clinical trial design, each new treatment must go through a strict development process. After successful Phase I trials, a Phase II trial is needed to show sufficient efficacy and safety. When this has been demonstrated, the medicine goes into Phase III trials, where it is compared with a standard treatment (control). Doing this for each treatment separately requires a long period of time, a large number of patients, and substantial financial resources. Additionally, in the traditional approach, modifications are not allowed during the course of the trial.

One new approach to clinical trial design is an adaptive clinical trial design. Adaptive clinical trials include a pre-planned opportunity for modification of one or more specified aspects of the trial. This is usually based on the analysis of interim data from participants during the trial.

There are many reasons to use adaptive designs (or adaptive pathways) in clinical trials. In an environment subject to economic challenges, adaptive designs appear to be appealing for pharmaceutical industry, academic institutions, clinicians, and patients.