Group-sequential two-stage designs

Group-sequential designs are a sub-class of the TwoStageDesign class with constant stage-two sample size. See TwoStageDesign for slot details. Any group-sequential design can be converted to a fully flexible TwoStageDesign (see examples section).

Usage

GroupSequentialDesign(n1, ...)

# S4 method for class 'numeric'
GroupSequentialDesign(
  n1,
  c1f,
  c1e,
  n2_pivots,
  c2_pivots,
  order = NULL,
  event_rate,
  ...
)

# S4 method for class 'GroupSequentialDesign'
TwoStageDesign(n1, event_rate, ...)

# S4 method for class 'GroupSequentialDesignSurvival'
TwoStageDesign(n1, ...)

Arguments

n1

stage one sample size or GroupSequentialDesign object to convert (overloaded from TwoStageDesign)

...

further optional arguments

c1f

early futility stopping boundary

c1e

early efficacy stopping boundary

n2_pivots

numeric of length one, stage-two sample size

c2_pivots

numeric vector, stage-two critical values on the integration pivot points

order

of the Gaussian quadrature rule to use for integration, set to length(c2_pivots) if NULL, otherwise first value of c2_pivots is repeated 'order'-times.

event_rate

probability that a subject in either group will eventually have an event, only needs to be specified for time-to-event endpoints.

See also

TwoStageDesign for superclass and inherited methods

Examples

design <- GroupSequentialDesign(25, 0, 2, 25, c(1, 1.5, 2.5))
summary(design)
#> GroupSequentialDesign: n1 =  25 
#> 
          futility |      continue     | efficacy
#> 
      x1:    -0.00 |  0.23  1.00  1.77 |  2.00
#> 
  c2(x1):     +Inf | +1.00 +1.50 +2.50 |  -Inf
#> 
  n2(x1):        0 |    25    25    25 |     0
#> 


design_survival <- GroupSequentialDesign(25, 0, 2, 25, c(1, 1.5, 2.5), event_rate = 0.7)

TwoStageDesign(design)
#> TwoStageDesign<n1=25;0.0<=x1<=2.0:n2=25> 

TwoStageDesign(design_survival)
#> TwoStageDesignSurvival<n_events1=25;0.0<=x1<=2.0;n_events2=25>