Background: The effectiveness of tenofovir-based oral PrEP for preventing HIV infection has ranged from 44-96% in clinical trials. We examined the cost-effectiveness of PrEP in MSM and TGW in Brazil.
Methods: We used the CEPAC-International model of HIV prevention and treatment to simulate clinical outcomes, costs, and cost-effectiveness of daily TDF-FTC PrEP among high-risk MSM and TGW in Brazil. Our comparator, no PrEP, featured guideline-concordant care, including universal ART access. In the PrEP strategy, high-risk HIV-negative adults age < 40y received daily PrEP, HIV testing every 4m, and annual creatinine. Base case parameters, derived from Brazil-specific sources, included mean age (31y), annual HIV incidence (age≤40y: 4.3/100PY; age>40y: 1.0/100PY), PrEP efficacy (86%), PrEP drug costs ($12.50/m), and PrEP program costs ($0.99/m). We varied key parameters in sensitivity analyses.
Results: Compared to no PrEP, PrEP decreased lifetime HIV infection risk by 37%. PrEP increased per person discounted (undiscounted) survival from 20.7 (36.9) to 22.4 (41.1) years and decreased lifetime medical costs from $4,090 ($10,910) to $3,470 ($7,660); PrEP was therefore cost-saving (Figure 1). PrEP remained cost-saving under key parameter variation, including PrEP cost, initial cohort age, and HIV testing frequency on/off PrEP. When PrEP was only used until age 30, PrEP ceased to be cost-saving, but its incremental cost-effectiveness ratio (ICER) remained < 1x Brazil''s per capita GDP. The ICER of PrEP also remained cost-saving or < 1xGDP when PrEP efficacy and HIV incidence varied widely (Figure 1), but exceeded 1xGDP when HIV incidence was ≤ 0.24 infections/100PY at base case PrEP efficacy (86%).
Conclusions: PrEP is cost-saving for MSM and TGW in Brazil. Our results strengthen local PrEP demonstration project results and offer justification for a future national PrEP program for MSM/TGW in Brazil.

StrategyTotal cohort cost/patientTotal cohort LE/patientHIV+ cases (% of cohort)% reduction in lifetime HIV infection riskAverage years to infection (SD)
No PrEP$4,09020.750.07%-13.7 (13.7)
PrEP$3,47022.431.57%37%24.2 (15.8)
All costs discounted at 3%/year; PrEP: pre-exposure prophylaxis; LE: life expectancy; HIV+: HIV-positive; SD: standard deviation
[Table 1. Base case results of an analysis of PrEP cost-effectiveness in Brazil]

Figure 1. Two-way sensitivity analysis of PrEP efficacy and incidence
[Figure 1. Two-way sensitivity analysis of PrEP efficacy and incidence]