Power and Sample Size for Randomized Phase III Survival Trials under the Weibull Model

摘要

Two parametric tests are proposed for designing randomized two-arm phase III survival trials under the Weibull model. The properties of the two parametric tests are compared with the non-parametric log-rank test through simulation studies. Power and sample size formulas of the two parametric tests are derived. The impact on sample size under mis-specification of the Weibull shape parameter is also investigated. The study can be designed by planning the study duration and handling nonuniform entry and loss to follow-up under the Weibull model using either the proposed parametric tests or the well known non-parametric log-rank test.