| dc.description.abstract | It is a common practice to perform well-designed phase II trials to select one or a few promising doses for larger scale phase III confirmatory trials. Certain phase II studies that aim at clinical events often face difficulties, such as long-term follow-up, large sample size but lack of patient resources, and expensive study supplies. Seamless phase II/III designs have gained much attention because of their potential to save development costs and to shorten time-to-market of a new compound compared to conventional drug development programmes with separate trials for individual phases. Two methods of adaptive seamless phase II/III trials, Shun (2007) and Friede (2011), the phase II trials are based on early endpoint data in, with special consideration given to the fact that no primary endpoint were observed in the interim analysis. In these cases, we considered appropriate ＂surrogate measures＂ as early endpoints for interim analysis. Finally, final statistical inferences were made based on the primary endpoint at two stages. Because the interim analysis will inflate the type-one error, Shun (2007) proposed a two-stage winner design, according to the distribution of the final test statistics, then find the critical value of the test under the specified significant level. In Friede (2011), closed testing procedure and weighted inverse normal combination function are used to control the inflation of overall type I error rate due to dose selection and p-values from two stage subjects at the final analysis. In this paper, the simulation is used to confirm whether the two methods can control the type-one error and compare the performance on the power. | en_US |