stopbound_post {ph2bayes}

The stopping boundaries based on Thall and Simon's criterion

Description

The stopping boundaries based on Thall and Simon's criterion.

Usage

stopbound_post(theta, type, nmax, alpha_e, beta_e, alpha_s, beta_s, delta)

Arguments

theta

the cutoff probability: typically, \theta = [0.95, 0.99] for superiority, \theta = [0.01, 0.05] for futility.

type

type of boundaries: "superiority" or "futility".

nmax

the maximum number of patients treated by the experimental drug.

alpha_e

the hyperparameter (shape1) of the Beta prior for the experimental drug.

beta_e

the hyperparameter (shape2) of the Beta prior for the experimental drug.

alpha_s

the hyperparameter (shape1) of the Beta prior for the standard drug.

beta_s

the hyperparameter (shape2) of the Beta prior for the standard drug.

delta

the minimally acceptable increment of the response rate for the experimental drug compared with the standard drug. Note: if type = "superiority", then delta is set to 0.

Value

boundset

the boundaries set; U_n or L_n

References

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.

Examples

stopbound_post(0.05, "futility", 40, 0.6, 1.4, 15, 35, 0)
stopbound_post(0.05, "futility", 30, 0.4, 1.6, 10, 40, 0)
stopbound_post(0.95, "superiority", 40, 0.6, 1.4, 15, 35, 0)