drugdevelopR (version 1.0.2)

EPsProg23_binary: Expected probability of a successful program deciding between two or three phase III trials for a binary distributed outcome

Description

The function EPsProg23_binary() calculates the expected probability of a successful program with a normally distributed outcome. This function follows a special decision rule in order to determine whether two or three phase III trials should be conducted. First, two phase III trials are performed. Depending on their success, the decision for a third phase III trial is made:

• If both trials are successful, no third phase III trial will be conducted.

• If only one of the two trials is successful and the other trial has a treatment effect that points in the same direction, a third phase III trial will be conducted with a sample size of N3 = N3(ymin), which depends on an assumed minimal clinical relevant effect (ymin). The third trial then has to be significant at level alpha

• If only one of the two trials is successful and the treatment effect of the other points in opposite direction or if none of the two trials are successful, then no third trial is performed and the drug development development program is not successful. In the utility function, this will lead to a utility of -9999.

Usage

EPsProg23_binary(
  RRgo,
  n2,
  alpha,
  beta,
  w,
  p0,
  p11,
  p12,
  in1,
  in2,
  case,
  size,
  ymin
)

Value

The output of the function EPsProg23_binary() is the expected probability of a successful program.

Arguments

RRgo

threshold value for the go/no-go decision rule

n2

total sample size for phase II; must be even number

alpha

significance level

beta

1-beta power for calculation of sample size for phase III

w

weight for mixture prior distribution

p0

assumed true rate of control group

p11

assumed true rate of treatment group

p12

assumed true rate of treatment group

in1

amount of information for p11 in terms of sample size

in2

amount of information for p12 in terms of sample size

case

choose case: "at least 1, 2 or 3 significant trials needed for approval"

size

size category "small", "medium" or "large"

ymin

assumed minimal clinical relevant effect

Examples

res <- EPsProg23_binary(RRgo = 0.8, n2 = 50,  alpha = 0.025, beta = 0.1, 
                                 w = 0.6,  p0 = 0.3, p11 =  0.3, p12 = 0.5, 
                                 in1 = 300, in2 = 600, case = 2, size = "small",
                                 ymin = 0.5)