pow.APPLE.plus {DelayedEffect.Design}

APPLE+ power computation

Description

Perform the power calculation using the close-form APPLE+ method based on the generalized piecewise weighted log-rank test when the treatment time-lag effect is present and the lag duration varies heterogeneously from individual to individual or from study to study, within a certain domain and following a specific pattern.

Usage

 pow.APPLE.plus(lambda1, tl, tu, N, HR, tao, A, ap=0.5, alpha=0.05)

Arguments

lambda1

Baseline hazard

tl

Lower bound of delayed duration domain

tu

Upper bound of delayed duration domain

N

Sample size

HR

Post-delay hazard ratio after tu, defined as the post-delay hazard rate of the treatment group compared to that of the control group

tao

Total study duration

A

Total enrollment duration

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 generalized Piecewise weighted Log-rank tEst with random treatment time-lag effect. See the reference for details of this method.

Value

The power

Author(s)

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

References

Xu, Z., Park, Y., Zhen, B. & Zhu, B. (2017). Achieving optimal power of logrank test with random treatment time-lag effect. Biometrika. Under review.

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

N.APPLE.plus, HR.APPLE.plus

Examples

  lambda1 <- 0.001982
  tl      <- 30
  tu      <- 30*11
  N       <- 200
  HR      <- 1.3
  tao     <- 365*3
  A       <- 365
  pow.APPLE.plus(lambda1, tl, tu, N, HR, tao, A)