drugdevelopR (version 1.0.2)

EPsProg_multitrial_normal: Expected probability of a successful program for multitrial programs with normally distributed outcomes

Description

These functions calculate the expected probability of a successful program given the parameters. Each function represents a specific strategy, e.g. the function EpsProg3_normal() calculates the expected probability if three phase III trials are performed. The parameter case specifies how many of the trials have to be successful, i.e. how many trials show a significantly relevant positive treatment effect.

Usage

EPsProg2_normal(
  kappa,
  n2,
  alpha,
  beta,
  w,
  Delta1,
  Delta2,
  in1,
  in2,
  a,
  b,
  case,
  size,
  fixed
)
EPsProg3_normal(
  kappa,
  n2,
  alpha,
  beta,
  w,
  Delta1,
  Delta2,
  in1,
  in2,
  a,
  b,
  case,
  size,
  fixed
)
EPsProg4_normal(
  kappa,
  n2,
  alpha,
  beta,
  w,
  Delta1,
  Delta2,
  in1,
  in2,
  a,
  b,
  case,
  size,
  fixed
)

Value

The output of the function EPsProg2_normal(), EPsProg3_normal() and EPsProg4_normal() is the expected probability of a successful program when performing several phase III trials (2, 3 or 4 respectively).

Arguments

kappa

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

Delta1

assumed true treatment effect for standardized difference in means

Delta2

assumed true treatment effect for standardized difference in means

in1

amount of information for Delta1 in terms of sample size

in2

amount of information for Delta2 in terms of sample size

a

lower boundary for the truncation

b

upper boundary for the truncation

case

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

size

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

fixed

choose if true treatment effects are fixed or random

Details

The following cases can be investigated by the software:

• Two phase III trials

  • Case 1: Strategy 1/2; at least one trial significant, the treatment effect of the other one at least showing in the same direction

  • Case 2: Strategy 2/2; both trials significant

• Three phase III trials

  • Case 2: Strategy 2/3; at least two trials significant, the treatment effect of the other one at least showing in the same direction

  • Case 3: Strategy 3/3; all trials significant

• Four phase III trials

  • Case 3: Strategy 3/4; at least three trials significant, the treatment effect of the other one at least showing in the same direction

Examples

EPsProg2_normal(kappa = 0.1, n2 = 50, alpha = 0.025, beta = 0.1, w = 0.3,
                                 Delta1 = 0.375, Delta2 = 0.625, in1 = 300, in2 = 600, 
                                 a = 0.25, b = 0.75, 
                                 case = 2, size = "small", fixed = FALSE)
          EPsProg3_normal(kappa = 0.1, n2 = 50, alpha = 0.025, beta = 0.1, w = 0.3,
                                 Delta1 = 0.375, Delta2 = 0.625, in1 = 300, in2 = 600, 
                                 a = 0.25, b = 0.75, 
                                 case = 2, size = "small", fixed = TRUE)
          EPsProg4_normal(kappa = 0.1, n2 = 50, alpha = 0.025, beta = 0.1, w = 0.3,
                                 Delta1 = 0.375, Delta2 = 0.625, in1 = 300, in2 = 600, 
                                 a = 0.25, b = 0.75, 
                                 case = 3, size = "small", fixed = TRUE)