Table 1.

Input Data Values for Analysis of PrEP

Variable	Baseline Value	Range Evaluated	Source
Initial cohort
Mean age (SD)	34 (9.4)	20 – 34	[40]
% male	100	---	Assumption
Average HIV incidence (per 100 person-years)	1.6	0.1 – 3.1	[29]
Incidence distribution by age (per 100 PY)			[29]
< 18 years	2.1	0.1 – 4.1
18 – 25 years	2.1	0.1 – 4.1
26 – 30 years	1.9	0.1 – 3.8
31 – 35 years	1.8	0.1 – 3.6
36 – 40 years	1.1	0.07 – 2.1
41 – 45 years	0.8	0.05 – 1.7
> 45 years	1.5	0.09 – 2.9
Viral load distribution if infected (%)			[30]
> 30,000 copies/ml	25.73	---
10,001 – 30,000 copies/ml	25.02	---
3,001 – 10,000 copies/ml	25.21	---
500 – 3,000 copies/ml	16.33	---
< 500 copies/ml	7.71
PrEP efficacya (%)	50	10 – 90	[31]

Efficacy of antiretroviral therapy without history of PrEP: % HIV RNA suppressed to <400 copies/ml (increase in CD4 cells/µl)b
	% HIV RNA suppressed to <400 copies/mlc		Increase in CD4 cells/µl c	Source
1. TDF/FTC + EFV	81		190	[32]
2. ATV/r + 2NRTIs	70		110	[33]
3. LPV/r + 2NRTIs	58		121	[33]
4. RAL + OBR	65 (24 weeks)		102 (24 weeks)	[34]
5. 50% ENF + OBR; 50%      MVC + OBR +/− ENFd	40 (24 weeks)		117 (24 weeks)	[35, 36]
6. OBR	12		45	[35]
Monthly Costs (2006 US$)		Baseline Value	Range evaluated	Source
Antiretroviral therapy				[37]
TDF/FTC + EFV		1,139	---
ATV/r + 2NRTIs		1,741	---
LPV/r + 2NRTIs		1,748	---
RAL + OBR		2,209	---
50% ENF + OBR; 50% MVC + OBR +/− ENF		3,338	---
OBR		1,549	---
PrEP (TDF/FTC)		753	101 – 753	[37–39]

PrEP = pre-exposure prophylaxis; SD = standard deviation; TDF = tenofovir; FTC = emtricitabine; EFV = efavirenz; ATV/r = ritonavir-boosted atazanavir; LPV/r = ritonavir-boosted lopinavir; RAL = raltegravir; OBR = optimized background regimen; ENF = enfuvirtide; MVC = maraviroc

^aPrEP efficacy is modeled as a net percent reduction in the monthly incidence of HIV infection, accounting for both the chemoprophylactic effect of PrEP and the potential offset of behavioral disinhibition.

^bValues reported in the table reflect values found in the original source papers. In some instances, results reported by authors on an “intention-to-treat” basis were adjusted to reflect an “as-treated” basis before being used in the model.

^cValues are reported at 48 weeks unless otherwise specified.

^dValues reported for this regimen are weighted averages of the values found in the two original source papers.