Modern Approaches to Clinical Trials Using SAS: Classical, Adaptive, and Bayesian Methods

3.1 Introduction

3.1.1 Motivation. Why Sample Size Re-estimation?

Sample size re-estimation (SSR) has received a lot of attention in recent years as a result of exploding interest in adaptive clinical trial designs in general. In February 2010, the Food and Drug Administration (FDA) issued a draft guidance on Adaptive Design Clinical Trials for Drugs and Biologics, which defined an adaptive design trial as “a study that includes a prospectively planned opportunity for modification of one or more specified aspects of the study design and hypotheses based on analysis of data (usually interim data) from subjects in the study. Analyses of the accumulating study data are performed at prospectively planned time points within the study, can be performed ...