# Table 9 Required Sample Size for High-Risk Group Patients with One Interim Analysis

Required Sample Size for High-Risk Group Patients with One Interim Analysis
Power = 80% Power = 90%
P0 = 80% P0 = 70% P0 = 80% P0 = 70%
P1 N1 N2 Total N1 N2 Total N1 N2 Total N1 N2 Total
70% 170 340 510 NA NA NA 235 470 705 NA NA NA
65% 78 156 234 827 1654 2481 108 216 324 1144 2288 3432
60% 45 90 135 211 422 633 62 124 186 292 584 876
55% 29 58 87 95 190 285 41 82 123 132 264 396
50% 21 42 63 54 108 162 28 56 84 74 148 222
45% 15 30 45 35 70 105 21 42 63 48 96 144
40% 12 24 36 24 48 72 16 32 48 33 66 99
35% NA NA NA 17 34 51 NA NA NA 24 48 72
1. P0: 30 days mortality rate in the standard arm. P1: 30 days mortality rate in the treatment arm
2. N1: sample size for the standard care arm. N2: sample size for the treatment arm
3. For 80% power: probability of rejection at each look: 1st look p < 0.006, futility look p > 0.709, final look p < 0.047
4. For 90% power: probability of rejection at each look: 1st look p < 0.006, futility look p > 0.716, final look p < 0.047
5. 1:2 randomization; p = 2