Table 2 Parameter values for trial re-analysis based on trial protocols

Number of arms

2

2

2

5

Targeted hazard ratio intermediate outcome

0.75

0.75

0.71

0.73

Targeted hazard ratio final outcome

0.75

0.74

0.71

0.73

Power at 1st stage

95%

95%

95%

95%

Power at 2nd stage

90%

90%

90%

90%

Overall power (given by nstage.ado program)

87.4%

87.4%

87.4%

87.4%

Significance level at 2nd stage (one-sided)

2.5%

2.5%

2.5%

0.5%

Overall significance level (for stage 1 α = 0.1)

1.39%

1.39%

1.39%

0.35%

Allocation ratio (control:experimental)

2:1

1:1

1:1

2:1:1:1:1

Intermediate outcome (median survival)

1.5 years

10 months

2.5 months

9 months

Final outcome (median survival)

3 years

23 months

10 months

9 months