Long-acting PrEP might offer a solution to the challenges of adherence

Potential clinical and economic value of long-acting preexposure prophylaxis for South African women at high-risk for HIV infection.

Walensky RP, Jacobsen MM, Bekker LG, Parker RA, Wood R, Resch SC, Horstman NK, Freedberg KA, Paltiel AD. J Infect Dis. 2015 Dec 17. pii: jiv523. [Epub ahead of print]

Background: For young South African women at risk for human immunodeficiency virus (HIV) infection, preexposure prophylaxis (PrEP) is one of the few effective prevention options available. Long-acting injectable PrEP, which is in development, may be associated with greater adherence, compared with that for existing standard oral PrEP formulations, but its likely clinical benefits and additional costs are unknown.

Methods: Using a computer simulation, we compared the following 3 PrEP strategies: no PrEP, standard PrEP (effectiveness, 62%; cost per patient, $150/year), and long-acting PrEP (effectiveness, 75%; cost per patient, $220/year) in South African women at high risk for HIV infection (incidence of HIV infection, 5%/year). We examined the sensitivity of the strategies to changes in key input parameters among several outcome measures, including deaths averted and program cost over a 5-year period; lifetime HIV infection risk, survival rate, and program cost and cost-effectiveness; and budget impact.

Results: Compared with no PrEP, standard PrEP and long-acting PrEP cost $580 and $870 more per woman, respectively, and averted 15 and 16 deaths per 1000 women at high risk for infection, respectively, over 5 years. Measured on a lifetime basis, both standard PrEP and long-acting PrEP were cost saving, compared with no PrEP. Compared with standard PrEP, long-acting PrEP was very cost-effective ($150/life-year saved) except under the most pessimistic assumptions. Over 5 years, long-acting PrEP cost $1.6 billion when provided to 50% of eligible women.

Conclusions: Currently available standard PrEP is a cost-saving intervention whose delivery should be expanded and optimized. Long-acting PrEP will likely be a very cost-effective improvement over standard PrEP but may require novel financing mechanisms that bring short-term fiscal planning efforts into closer alignment with longer-term societal objectives.

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Editor’s notes: Standard oral pre-exposure prophylaxis (PrEP) is effective in preventing HIV and is one of the few proven prevention options available to young women at risk of HIV. However, daily adherence is key and trials have illustrated problems with adherence in several populations. Development of long-acting injectable formulations of PrEP may provide an option that does not require daily adherence to pills. In anticipation of new formulations of PrEP, this study modelled the potential clinical benefits, additional cost, cost-effectiveness and budget impact of existing and novel PrEP strategies. Given that the effectiveness and cost of long-acting PrEP is unknown, sensitivity analyses were conducted to look at varied effectiveness, HIV infection incidence, age at PrEP discontinuation and programmatic cost. The results suggest that long-acting PrEP is likely to be more clinically and cost-effective than standard oral PrEP. However, it will place an even greater strain on existing HIV prevention budgets. In addition to the research necessary to establish its clinical effectiveness, efforts to develop novel financing mechanisms are also required.         

South Africa
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