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

Table 4 Required Sample Size for High-Risk Group Patients with Two Interim Analyses

Required Sample Size for High-Risk Group Patients with Two Interim Analyses
	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%	171	342	513	NA	NA	NA	237	474	711	NA	NA	NA
65%	79	158	237	833	1666	2499	109	218	327	1155	2310	3465
60%	45	90	135	213	426	639	63	126	189	295	590	885
55%	30	60	90	96	192	288	41	82	123	133	266	399
50%	21	42	63	54	108	162	29	58	87	75	150	225
45%	15	30	45	35	70	103	21	42	63	48	96	144
40%	12	24	34	24	48	72	16	32	48	33	66	99
35%	NA	NA	NA	17	34	51	NA	NA	NA	24	48	72

P0: 30 days mortality rate in the standard arm. P1: 30 days mortality rate in the treatment arm
N1: sample size for the standard care arm. N2: sample size for the treatment arm
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
1:2 randomization; ρ = 3.0
Bold indicates recommended sample size with suggested parameters

ISSN: 1471-2288