Table 1. BioPET analysis of a biomarker with area under the receiver operating characteristic curve =0.72.

The clinical event occurs in 20% of patients without intervention. A trial of an intervention to help prevent the clinical event is designed to have 90% power to detect a 30% relative reduction in the event rate using one-sided hypothesis testing and α=0.025. The cost of screening is $1000 and the per patient trial cost is $10,000. The Screening Threshold is the proportion of patients who will be screened out of the trial. The Event Rate is the rate of the clinical event in the enriched study population not receiving the intervention. The Sample Size is the trial sample size calculated as a function of the event rate and statistical testing specifications. Total Screened is the total number of patients who would need to be screened to enroll the trial, which depends on the sample size and stringency of screening. Total Cost summarizes patient-related costs of different levels of enrichment, specifically the costs of biomarker-based screening and the costs of having a patient in a trial. The results here are also displayed in Figure 1.

Screening Threshold	Event Rate	Sample Size	Total Screened	Total Cost	Percent Reduction in Total Cost
0%	0.20	1643	1643	16431723	Ref
5%	0.21	1562	1645	17268036	−5.1%
10%	0.22	1488	1653	16530257	−0.6%
15%	0.23	1418	1669	15853049	3.5%
20%	0.23	1352	1690	15210458	7.4%
25%	0.24	1287	1716	14584524	11.2%
30%	0.25	1225	1751	14004331	14.8%
35%	0.26	1165	1792	13443614	18.2%
40%	0.27	1106	1843	12904180	21.5%
45%	0.29	1047	1903	12372557	24.7%
50%	0.30	989	1978	11865727	27.8%
55%	0.31	928	2063	11348024	30.9%
60%	0.33	869	2172	10862124	33.9%
65%	0.34	811	2316	10421107	36.6%
70%	0.36	751	2503	10013428	39.1%
75%	0.39	689	2755	9640789	41.3%
80%	0.41	622	3108	9323150	43.3%
85%	0.44	552	3681	9202643	44.0%
90%	0.49	476	4759	9517265	42.1%
95%	0.55	381	7621	11431165	30.4%