Description Usage Arguments Value Note Author(s) References Examples

Sample size calculation for Fleming-Harrington weighted log-rank tests This sample size calculation method was proposed by Hasegawa (2014). This function is to calculate the sample size for Fleming-Harrington weighted log-rank tests with piece-wise exponential distributed survival curves in described in Hasegawa(2014).

1 2 3 4 5 6 7 8 9 10 11 12 13 | ```
sample.size_FH(
eps,
p,
b,
tau,
omega,
lambda,
lambda.trt,
rho,
gamma,
alpha,
beta
)
``` |

`eps` |
The change point, before which, the hazard ratio is 1, and after which, the hazard ratio is theta |

`p` |
Treatment assignment probability. |

`b` |
The number of subintervals per time unit. |

`tau` |
The end of the follow-up time in the study. Note that this is identical to |

`omega` |
The minimum follow-up time for all the patients. Note that Hasegawa(2014) assumes that the accrual is uniform between time 0 and R, and there does not exist any censoring except for the administrative censoring at the ending time |

`lambda` |
The hazard for the control group. |

`lambda.trt` |
The hazard for the treatment group after time eps. |

`rho` |
The first parameter for Fleming Harrington weighted log-rank test: |

`gamma` |
The second parameter for Fleming Harrington weighted log-rank test: |

`alpha` |
Type I error. |

`beta` |
Type II error. |

`n` |
The needed sample size. |

`n_event` |
The needed event numbers for both arms together. |

`E.star` |
The unit mean, correspoinding to |

`sum_D` |
The cumulative D, and ceiling(n*D) is quivalent to n_vent. |

This function is based on a R function from Dr. Ting Ye's paper : Ye, T., & Yu, M. (2018). A robust approach to sample size calculation in cancer immunotherapy trials with delayed treatment effect. Biometrics, 74(4), 1292-1300.

Lili Wang, Ting Ye

Ye, T., & Yu, M. (2018). A robust approach to sample size calculation in cancer immunotherapy trials with delayed treatment effect. Biometrics, 74(4), 1292-1300. Hasegawa, T. (2014). Sample size determination for the weighted log‐rank test with the Fleming–Harrington class of weights in cancer vaccine studies. Pharmaceutical statistics, 13(2), 128-135.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | ```
## Not run:
# Example 1 from Hasegawa (2014)
p<-2/3
tau<-66
omega<-18
eps<-6
m1=21.7 #median survival time for placebo group
m2=25.8 # median survival time for treatment group
lambda<-log(2)/m1
lambda.trt<-log(2)*(m1-eps)/(m2-eps)/m1
theta=lambda.trt/lambda
alpha<-0.025
beta<-0.1
rho=0
gamma=1
b=30
sample.size_FH(eps,p,b,tau,omega,lambda,lambda.trt,rho, gamma,alpha,beta)$n
#1974, identical to the paper's report
## End(Not run)
``` |

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