Description Usage Arguments Details Value References See Also Examples

The package calculates the study sample size and power in designing clinical trials using the difference in restricted mean survival time (RMST). Two types of one-sided tests, non-inferiority and superiority tests, are prepared. Under certain conditions, 2,000 sets of realizations in default are generated for calculating confidence intervals of RMST differences. Then the power is calculated, i.e., the chance that the lower bound of 2,000 confidence intervals of RMST differences falls above a margin.

1 2 3 |

`ac_rate` |
Accrual rate: the number of patients per unit time. |

`ac_period` |
Accrual period: the time point at last accrual. |

`ac_number` |
Accrual number: the total number of accrual patients. |

`tot_time` |
Total study time: the time point at last follow-up. |

`tau` |
Truncation time point to calculate RMSTs. |

`shape0, shape1` |
Shape parameters for the Weibull distribution in both the control (arm0) and the treatment (arm1). |

`scale0, scale1` |
Scale parameters for the Weibull distribution in both the control (arm0) and the treatment (arm1). Note that when the PH assumption is assumed, the value of the scale parameter in the treatment (arm1) needs to be larger than or equal to that in the control (arm0), because the difference of the RMSTs (arm1 minus arm0) is of interest. |

`margin` |
Non-inferiority margin: a clinically acceptable difference in RMST. A value of minus |

`allocation1` |
Proportion of patients allocated to the treatment (arm1). Default value is 0.5. |

`one_sided_alpha` |
Nominal type I error level as one-sided. When default ( |

`seed` |
Random seed used for the sampling. Default is |

`ntest` |
Number of iterations. When default ( |

For more details, please refer to the vignette: `browseVignettes(package = "SSRMST")`

A list with components:

`result` |
Total study population and expected number of events. |

`power1` |
The power based on separate variance, i.e., the chance that the lower bound of 2,000 confidence intervals of difference in RMST falls above a value of minus margin in a non-inferiority test (or above 0 in a superiority test). |

`power2` |
The power based on pooled variance, i.e., the chance that the lower bound of 2,000 confidence intervals of difference in RMST falls above a value of minus margin in a non-inferiority test (or above 0 in a superiority test). |

`ac_rate` |
Accrual rate used in the analyses. |

`ac_period` |
Accrual period used in the analyses. |

`ac_number` |
Accrual number used in the analyses. |

`ac_type` |
Accrual type: 1; the number of patients per unit time is automatically calculated by specifying the parameters (ac_rate and ac_period), 2; the accrual rate is automatically calculated by specifying the parameters (ac_period and ac_number), 3; the accrual period is automatically calculated by specifying the parameters (ac_rate and ac_number). |

`tot_time` |
Total study time used in the analyses. |

`margin` |
Margin used in the analyses. |

`tau` |
Truncation time point used in the analyses. |

`one_sided_alpha` |
Nominal type I error level as one-sided used in the analyses. |

`note` |
Note regarding the truncation time, tau. |

Uno H, Wittes J, Fu H, Solomon SD, Claggett B, Tian L, Cai T, Pfeffer MA, Evans SR, Wei LJ. Alternatives to Hazard Ratios for Comparing the Efficacy or Safety of Therapies in non-inferiority Studies. Annals of Internal Medicine 2015, 163, 127-134.

survival survRM2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | ```
#---Example data
#--Non-inferiority test
ac_rate = 15
ac_period = 35
tot_time = 510
tau = 500
scale0 = 8500
scale1 = 8500
margin = 18
a = ssrmst(ac_rate=ac_rate, ac_period=ac_period, tot_time=tot_time,
tau=tau, scale0=scale0, scale1=scale1, margin=margin, ntest=20)
print(a)
#--Superiority test
ac_rate = 15
ac_period = 35
tot_time = 510
tau = 500
scale0 = 4000
scale1 = 8500
b = ssrmst(ac_rate=ac_rate, ac_period=ac_period, tot_time=tot_time,
tau=tau, scale0=scale0, scale1=scale1, ntest=20)
print(b)
``` |

```
Non-inferiority test
Total arm0 arm1
Sample size 524 262 262
Expected number of events 31 16 15
Power (separate)
0.85
Power (pooled)
0.85
Superiority test
Total arm0 arm1
Sample size 524 262 262
Expected number of events 43 29 14
Power (separate)
0.65
Power (pooled)
0.65
```

SSRMST documentation built on May 29, 2017, 8:30 p.m.

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