HR.APPLE {DelayedEffect.Design}

APPLE hazard ratio computation

Description

Perform the post-delay hazard ratio calculation given power and sample size using the close-form APPLE method based on the piecewise weighted log-rank test when the treatment time-lag effect is present and the lag duration is homogeneous across the individual subject

Usage

 HR.APPLE(lambda1, t1, p, N, tao, A, beta, ap=0.5, alpha=0.05) 

Arguments

lambda1

Baseline hazard or NULL (see details)

t1

Delayed duration or NULL (see details)

p

Proportion of subjects who survive beyond the delayed period or NULL (see details)

N

Sample size

tao

Total study duration

A

Total enrollment duration

beta

Type II error rate; Power=1-beta

ap

Experimental-control allocation ratio. The default is 0.5.

alpha

Type I error rate (two-sided). The default is 0.05.

Details

APPLE is an acronym for:
Analytic Power calculation method based on Piecewise weighted Log-rank tEst. See the reference for details of this method.

Out of the three input parameters lambda1, t1 and p, only two need to be specified, the remaining one will be computed internally from the formula lambda1 = -log(p)/t1. If all three are not NULL, then lambda1 will be set to -log(p)/t1 regardless of the user input value.

Value

The hazard ratio

Author(s)

Zhenzhen Xu <[e-mail]>, Boguang Zhen<[e-mail]>, Yongsoek Park <[e-mail]> and Bin Zhu <[e-mail]>

References

Xu, Z., Zhen, B., Park, Y., & Zhu, B. (2017). Designing therapeutic cancer vaccine trials with delayed treatment effect. Statistics in medicine, 36(4), 592-605.

See Also

pow.APPLE, N.APPLE

Examples

  lambda1 <- NULL
  t1      <- 183
  p       <- 0.7
  N       <- 200
  tao     <- 365*3
  A       <- 365
  beta    <- 0.2
  HR.APPLE(lambda1, t1, p, N, tao, A, beta)