Eight predictive powers with historical and interim data for futility and efficacy analysis

When the historical data of the early phase trial and the interim data of the Phase III trial are available, we should use them to give a more accurate prediction in both futility and efficacy analysis. The predictive power is an important measure of the practical utility of a proposed trial, and it is better than the classical statistical power in giving a good indication of the probability that the trial will demonstrate a positive or statistically significant outcome. In addition to the four predictive powers with historical and interim data available in the literature and summarized in Table 1, we discover and calculate another four predictive powers also summarized in Table 1, for one-sided hypotheses. Moreover, we calculate eight predictive powers summarized in Table 2, for the reversed hypotheses. The combination of the two tables gives us a complete picture of the predictive powers with historical and interim data for futility and efficacy analysis. Furthermore, the eight predictive powers with historical and interim data are utilized to guide the futility analysis in the tamoxifen example. Finally, extensive simulations have been conducted to investigate the sensitivity analysis of priors, sample sizes, interim result and interim time on different predictive powers.