Requiring an amyloid-β1-42 biomarker may improve the efficiency of a study, and simulations may help in planning studies

Table 1 Summary statistics and power from Schneider and colleagues with absolute effect size (column J), percentage placebo effect (column K) and sensitivity (column L) in additional columns

A	B	C	D	E	F	G	H	I	J	K	L
n per group	Dropout (%)	Effect size (J/H = K × L)	Selection method	TRT mean	PBO mean	TRT SD	PBO SD	Power, mixed model	Absolute treatment effect (F - E)	Percentage placebo effect (J/F)	Sensitivity (signal to noise ratio) (F/H)
100	20	0.35	aMCI	0.88	2.86	5.92	5.62	0.56	1.98	0.69	0.51
100	20	0.35	Ab	1.66	3.71	6.18	5.85	0.58	2.05	0.55	0.63
100	20	0.35	t-tau/Ab	1.58	3.66	6.27	5.92	0.57	2.08	0.57	0.62
100	20	0.45	aMCI	0.33	2.85	6.03	5.61	0.71	2.52	0.88	0.51
100	20	0.45	Ab	1.04	3.73	6.25	5.88	0.76	2.69	0.72	0.63
100	20	0.45	t-tau/Ab	0.99	3.65	6.41	5.94	0.73	2.66	0.73	0.61
200	20	0.25	aMCI	0.85	2.84	5.93	5.62	0.54	1.99	0.70	0.51
200	20	0.25	Ab	1.66	3.72	6.22	5.88	0.56	2.06	0.55	0.63
200	20	0.25	t-tau/Ab	1.55	3.67	6.27	5.96	0.61	2.12	0.58	0.62
200	20	0.35	aMCI	0.32	2.85	6.08	5.65	0.78	2.53	0.89	0.50
200	20	0.35	Ab	1.05	3.71	6.28	5.86	0.83	2.66	0.72	0.63
200	20	0.35	t-tau/Ab	0.96	3.64	6.4	5.95	0.85	2.68	0.74	0.61
200	40	0.35	aMCI	0.89	2.85	5.97	5.65	0.7	1.96	0.69	0.50
200	40	0.35	Ab	1.65	3.68	6.18	5.86	0.71	2.03	0.55	0.63
200	40	0.35	t-tau/Ab	1.57	3.65	6.3	5.95	0.73	2.08	0.57	0.61
200	40	0.45	aMCI	0.32	2.87	6.1	5.65	0.86	2.55	0.89	0.51
200	40	0.45	Ab	1.06	3.7	6.34	5.87	0.88	2.64	0.71	0.63
200	40	0.45	t-tau/Ab	0.93	3.68	6.36	5.99	0.9	2.75	0.75	0.61
400	20	0.25	aMCI	1.45	2.86	5.92	5.63	0.81	1.41	0.49	0.51
400	20	0.25	Ab	2.23	3.7	6.15	5.88	0.84	1.47	0.40	0.63
400	20	0.25	t-tau/Ab	2.17	3.68	6.23	5.98	0.87	1.51	0.41	0.62
400	40	0.25	aMCI	0.86	2.85	6	5.66	0.71	1.99	0.70	0.50
400	40	0.25	Ab	1.67	3.7	6.27	5.89	0.77	2.03	0.55	0.63
400	40	0.25	t-tau/Ab	1.54	3.68	6.32	6	0.76	2.14	0.58	0.61
400	40	0.35	aMCI	1.46	2.86	5.92	5.63	0.93	1.4	0.49	0.51
400	40	0.35	Ab	2.25	3.73	6.14	5.88	0.94	1.48	0.40	0.63
400	40	0.35	t-tau/Ab	2.16	3.67	6.23	6	0.95	1.51	0.41	0.61

Adapted with permission from Table 2 of Schneider and colleagues [1]. TRT, treatment; PBO, placebo; SD, standard deviation; aMCI, amnestic mild cognitive impairment; Ab, requires low Ab_1-42 biomarker for enrollment; t-tau, requires high total tau to Ab_1-42 ratio for enrollment.

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