Thall and Simon's criterion function for determining the trial decision cutoffs based on the posterior probability.
postprob(y, n, alpha_e, beta_e, alpha_s, beta_s, delta)the number of responses among \(n\) patients treated by the experimental drug at a certain stage of the trial.
the number of patients treated by the experimental drug at a certain stage of the trial.
the hyperparameter (shape1) of the Beta prior for the experimental drug.
the hyperparameter (shape2) of the Beta prior for the experimental drug.
the hyperparameter (shape1) of the Beta prior for the standard drug.
the hyperparameter (shape2) of the Beta prior for the standard drug.
the minimally acceptable increment of the response rate for the experimental drug compared with the standard drug.
the posterior probability: \(\Pr(p_E > p_S + \delta | y)\)
Thall, P. F., Simon, R. (1994). Practical Bayesian guidelines for phase IIB clinical trials. Biometrics 50: 337-349.
Yin, G. (2012). Clinical Trial Design: Bayesian and Frequentist Adaptive Methods. New York: Wiley.