FutIM {HCTDesign}

Monitoring the trial at interim looks for a trial with futility monitoring only

Description

Calculates one-sided futility boundary values at the observed number of events.

Usage

FutIM(
  d2,
  dmax,
  last.look = FALSE,
  d1,
  etam,
  alpha,
  beta,
  opt = "OBF",
  param = 4
)

Arguments

d2

vector of number of events at which you want to monitor the trial.

dmax

maximum number of events in the experimental group caculated from design function.

last.look

logical which indicates whether the current look is the last look or not. Default is FALSE.

d1

total number of events in the historical control group.

etam

value of the drift parameter obtained from design function.

alpha

type I error.

beta

type II error.

opt

type of spending function: "OBF", "Gamma", "Rho" or "Pocock". Default is "OBF".

param

Parameter for Gamma family or Rho family. Default value is 4.

Details

The number of events have to be entered sequentially. See example.

Value

A list containing futility boundary values along with the p-values and transformed information time for the current look.Post-hoc power is also calculated in case of early stopping of the trial.

Author(s)

Tushar Patni, Yimei Li, Jianrong Wu, and Arzu Onar-Thomas.

References

Wu J, Xiong X (2016). “Survival trial design and monitoring using historical controls.” Pharmaceutical Statistics, 15(5), 405-411.

Wu J, Li Y (2020). “Group sequential design for historical control trials using error spending functions.” Journal of Biopharmaceutical Statistics, 30(2), 351-363.

Examples

#Interim look for the trial when the number of events is 13(first look).
gg<-FutIM(c(13),dmax=57,alpha=0.05,beta=0.1,etam=3.0726,d1=65,opt="OBF",last.look=FALSE)
#Interim look for the trial when the number of events is 35(second look).
gg<-FutIM(c(13,35),dmax=57,alpha=0.05,beta=0.1,etam=3.0726,d1=65,opt="OBF",last.look=FALSE)