Multi-arm Multi-stage (MAMS) Platform Randomized Clinical Trials

Efficient clinical trial designs are needed to speed up the evaluation of new therapies. The multi-arm multi-stage (MAMS) randomized clinical trial designs have been proposed to achieve this goal. In this framework, multiple experimental treatments are compared against a common control arm in several stages. This approach has several advantages over the more traditional designs since it obviates the need for multiple two-arm studies, and allows poorly performing experimental treatments to be discontinued during the study. To further increase efficiency, Royston and colleagues proposed a particular class of MAMS designs where an intermediate outcome can be used at the interim stages, thus allowing phases II and III of evaluation to be incorporated under one protocol. The MAMS Platform designs speed up the evaluation process even further by allowing new treatments to be introduced for assessment during the course of a MAMS trial. In this chapter, we describe the rationale for Royston et al.’s MAMS design, and discuss their underlying principles. An example in prostate cancer is used to explain how the MAMS design can be realized in practice. We present analytical solutions for the strong control of the type I and II error rates, and show how these quantities and the required sample size can be calculated using available software. We also describe the challenges in the design and statistical analysis of such trials, and suggest how these difficulties should be addressed. The MAMS platform design has been used in a variety of disease areas, and holds considerable promise for speeding up the evaluation of new treatments where many new regimens are available for testing in the randomized phase II and phase III trials.