Simulation settings
To assess the operating characteristics of our new methods STE–CP and STE–PoS and to compare them to Kunz’s design, we conducted a simulation study. We assumed a phase II trial with long-term survival as a primary endpoint and the option to stop for futility. Long-term survival was defined as survival after 12 months and measurements were obtained every 3 months, so there were four measurement time points in total and Visualization of the prior distributions used in the simulation and the posterior distribution for the example interim data presented in For all three designs, an interim analysis was conducted once Null and alternative hypothesis for the long-term endpoint (after 12 months) with various scenarios for the short-term endpoint (after 3 months) and the corresponding Weibull survival functions with shape parameter For illustration purposes, a single simulation run is summarized in Summary of example simulation run generated under scenario 1. Note that STE–PoS uses the whole posterior distribution, even though in this table only the posterior means are displayed.Distribution of CP according to STE–CP and the PoS according to STE–PoS for all pairs of null and alternative hypothesis within scenario 1. Results of scenarios 2 and 3 are presented in the Supplementary Material. CP: conditional power; PoS: probability of success; STE: short-term endpoints.