Statistical design of Phase II/III clinical trials for testing therapeutic interventions in COVID-19 patients

Table 6 Required Sample Size for Intermediate-Risk Group Patients with One Interim Analysis

Required Sample Size for Intermediate-Risk Group Patients with One Interim Analysis
Effect Size		α = 0.05 with 1:1 Group Ratio		α = 0.05 with 1:2 Group Ratio
Effect Size	Power	80%	90%	80%	90%
10%	N1	313	433	234	323
	N2	313	433	468	646
	Total	626	866	702	969
15%	N1	139	192	104	143
	N2	139	192	208	286
	Total	278	384	312	429
20%	N1	77	106	58	80
	N2	77	106	116	160
	Total	154	212	174	240
25%	N1	48	67	37	50
	N2	48	67	74	100
	Total	96	134	111	150
30%	N1	32	45	25	34
	N2	32	45	50	68
	Total	64	90	75	102
35%	N1	23	31	18	25
	N2	23	31	36	50
	Total	46	62	54	75
40%	N1	16	23	13	18
	N2	16	23	26	36
	Total	32	46	39	54

N1: sample size for the standard care arm. N2: sample size for the treatment arm
Response rate = 40%
For 80% power: probability of rejection at each look: 1^st look p < 0.006, futility look p > 0.709, final look p < 0.047
For 90% power: probability of rejection at each look: 1^st look p < 0.006, futility look p > 0.716, final look p < 0.047
p = 2.0

ISSN: 1471-2288