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

Table 2 Required Sample Size for Intermediate-Risk Group Patients with Two Interim Analyses

Required Sample Size for Intermediate-Risk Group Patients with Two Interim Analyses
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	315	438	235	326
	N2	315	438	470	652
	Total	630	876	705	978
15%	N1	140	194	104	145
	N2	140	194	208	290
	Total	280	388	312	435
20%	N1	78	108	58	81
	N2	78	108	116	162
	Total	156	216	174	243
25%	N1	49	67	37	51
	N2	49	67	74	102
	Total	98	134	111	153
30%	N1	33	45	25	35
	N2	33	45	50	70
	Total	66	90	75	105
35%	N1	23	32	18	25
	N2	23	32	36	50
	Total	46	64	54	75
40%	N1	17	23	13	18
	N2	17	23	26	36
	Total	34	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 < 0.002, futility look p > 0.835, 2^nd look p < 0.014, futility look p > 0.312, final look p < 0.046
For 90% power: probability of rejection at each look: 1^st look p < 0.002, futility look p > 0.830, 2^nd look p < 0.014, futility look p > 0.298, final look p < 0.046
ρ = 3.0
Bold indicates recommended sample size with suggested parameters

ISSN: 1471-2288