OneArmPhaseTwoStudy: An R Package for Planning, Conducting, and Analysing Single-Arm Phase II Studies

In clinical phase II studies, the efficacy of a promising therapy is tested in patients for the first time. Based on the results, it is decided whether the development programme should be stopped or whether the benefit-risk profile is promising enough to justify the initiation of large phase III studies. In oncology, phase II trials are commonly conducted as single-arm trials with planned interim analyses to allow for an early stopping for futility. The specification of an adequate study design that guarantees control of the type I and II error rates is a key task in the planning stage of such a trial. A variety of statistical methods exists which can be used to optimise the planning and analysis of such studies. However, there are currently neither commercial nor non-commercial software tools available that support the practical application of these methods comprehensively. The R package OneArmPhaseTwoStudy was implemented to fill this gap. The package allows determining an adequate study design for the particular situation at hand as well as monitoring the progress of the study and evaluating the results with valid and efficient analyses methods. This article describes the features of the R package and its application.