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Approximate required numbers of observed (total) treatment failures for screening trials with PFS endpoints, using the logrank test
| Error rates | Hazard Ratios (Δ) | |||
|---|---|---|---|---|
| Δ=1.3 | Δ=1.4 | Δ=1.5 | Δ=1.75 | |
| (α,β)=(10%,10%) | 382 | 232 | 160 | 84 |
| (α,β)=(10%,20%) or (20%,10%) |
262 | 159 | 110 | 58 |
| (α,β)=(20%,20%) | 165 | 100 | 69 | 36 |
Note: Calculations were carried out using nQueryAdvisor 5.0 software (Statistical Solutions, Saugus, MA) based on methods given in Collett [26] with 1-sided α
