Simon’s two-stage design
We consider the case of a standard phase II single-arm clinical trial in the field of oncology with a binary endpoint with the option to stop for futility. Such a design was proposed by SimonFor futility stopping, an important operating characteristic of Simon’s two-stage design is the probability of early termination (PET). Under the null hypothesis, the PET should be large, while under the alternative hypothesis, it should be small, and definitely not larger than 