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).

GroupSequentialDesign(n1, ...)

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

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

# S4 method for 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 uadrature 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.

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>

Arguments

See also

Examples