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Costs and benefits of on-demand HIV preexposure prophylaxis in MSM

Durand-Zaleski, Isabellea,b,c,d; Mutuon, Pierrea; Charreau, Isabellee; Tremblay, Cecilef; Rojas, Danielag; Pialoux, Gillesh; Chidiac, Christiani; Capitant, Catherinee; Spire, Brunoj,k,l,m,n; Cotte, Laurenti; Chas, Julieh; Meyer, Laurencee; Molina, Jean, Michell,m,nfor the ANRS IPERGAY Study Group

doi: 10.1097/QAD.0000000000001658
EPIDEMIOLOGY AND SOCIAL
Free

Objectives: We undertook the economic evaluation of the double-blind randomized ANRS-IPERGAY trial, which showed the efficacy of on-demand preexposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF)-emtricitabine (FTC) in preventing HIV infection among high-risk MSM.

Design and methods: The economic evaluation was prospective. Counseling, drugs (TDF-FTC at €500.88 for 30 tablets), tests, visits, and hospital admissions were valued based on in-trial use. The cost of on-demand PrEP/HIV infection averted was compared with the yearly and lifetime costs of HIV infection in France in a cost and benefits analysis.

Results: The yearly number of participants needed to treat to prevent one HIV infection was 17.6 (95% confidence interval = 10.7–49.9). The annual cost of counseling was €690/participant. The total 1-year costs of PrEP were €4271/participant, of which €3129 (73%) were drug costs corresponding to 15 tablets of TDF-FTC/month. The yearly cost of on-demand PrEP to avoid one infection was €75 258. Using TDF-FTC generic (€179.9/30 tablets) reduced the 1-year costs of on-demand PrEP to €2271/participant and €39 970/infection averted, respectively. Using TDF-FTC at international market discounted prices (€60/30 tablets) reduced the costs to €1517/participant and the cost to €26 787/infection averted, comparable with the yearly treatment cost of HIV infection in France. On-demand PrEP was found to be cost saving in France if the duration of exposure was less than 7.5 years at current drug price and 13 years at generic price.

Conclusion: On-demand PrEP in high-risk MSM with TDF-FTC can be considered cost saving. Other benefits include the treatments of other diseases and reductions in secondary infections.

aHealth Economics Research Unit, Hôtel Dieu, Paris

bHôpital Henri Mondor, AP-HP

cUniversité Paris Est Créteil, Créteil

dINSERM ECEVE UMR 1123

eINSERM SC10 US019, Paris France

fCentre Hospitalier de l’Université de Montréal, Montréal, Québec, Canada

gAssociation AIDES, Pantin

hDepartment of Infectious Diseases, Hôpital Tenon, AP-HP, Paris

iHôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon

jINSERM, UMR912 (SESSTIM)

kUMR_S912, IRD, Aix Marseille Université, Marseille

lDepartment of Infectious Diseases, Hôpital Saint-Louis, AP HP

mUniversité de Paris Diderot Paris 7, Sorbonne Paris Cité

nINSERM UMR 941, Paris, France.

Correspondence to Isabelle Durand-Zaleski, MD, PhD, URCEco and Department of Public Health, APHP Hopital de l’Hotel Dieu, Paris France. Tel: +33 140274143; e-mail: isabelle.durand-zaleski@aphp.fr

Received 28 March, 2017

Revised 5 September, 2017

Accepted 8 September, 2017

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Research in context

Evidence before this study

On-demand preexposure prophylaxis (PrEP), using oral formulations of the antiretroviral drugs tenofovir disoproxil fumarate (TDF)-emtricitabine (FTC), has been approved for use in France, whereas the US Food and Drug Administration regulatory approval was granted in July 2012 for daily PrEP. The high drug cost was reported as a particularly important hindrance to the affordability of PrEP in the USA.

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Added value of this study

We estimated from trial-based information the efficiency of providing on-demand PrEP to MSM compared to placebo. Comparison with lifetime cost of HIV infection showed on-demand PrEP to be cost saving up to 7.5 years of risk exposure or 13 years at generic price.

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Implications of all the available evidence

On-demand PrEP is largely cost saving in populations with a high incidence of HIV, short duration of risk exposure with generic prices.

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Introduction

In a randomized clinical trial conducted in France, on-demand PrEP, using oral formulations of the antiretroviral drugs TDF-FTC, has been shown to significantly reduce the risk of HIV infection among high-risk MSM [1]. Following the publication of these results, the daily oral PrEP product, TDF-FTC (Truvada; GILEAD Sciences, Boulogne-Billancourt, France), has been approved for use in France, whereas the US Food and Drug Administration regulatory approval was granted in July 2012 [2]. Cost considerations, uncertainty regarding the cost-effectiveness of PrEP by population type, assumptions on drug prices and ethical concerns regarding the allocation of healthcare resources have been outlined as key issues to be addressed to reassure policy makers about PrEP programs [3]. The high drug cost was reported as a particularly important hindrance to the affordability of PrEP in the United States: authors concluded that a PrEP program might not be affordable because of the high cost of drugs used for PrEP (US$8000 to 9300/person-year for PrEP drugs only) [4]. Previous economic evaluations have estimated the cost-effectiveness of PrEP by modeling the expected outcomes and costs of prevention in different settings and populations at risk [5–8].

Our objective was to estimate the cost/HIV infection averted and the potential net monetary benefit of on-demand PrEP in the setting of the IPERGAY trial. This economic evaluation is, to our knowledge, the first trial-based analysis of on-demand PrEP in a Western population among high-risk MSM.

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Participants and methods

The design and results of the IPERGAY trial have been reported [1]. In short, 400 participants without HIV infection were enrolled (199 in the TDF-FTC group and 201 in the placebo group) at seven sites (six in France and one in Canada) and followed for a median of 9.3 months and a mean of 12.9 months. All participants received counseling at the time of enrolment and during each follow-up visit.

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Economic evaluation

The prospective economic evaluation was conducted from the healthcare perspective to determine the cost/infection averted and the potential cost savings with PrEP compared with placebo which represented the alternative at the time of the trial. Healthcare resources included: dispensary visits and counseling, consultations, hospital admissions, diagnostic tests and drugs. We included in the economic calculations all healthcare resources that we assumed would be part of normal healthcare utilization for a person on PrEP and thus, the cost of the protocol-driven consultations was calculated but excluded from the economic evaluation. Counseling was provided by the AIDES network. At every scheduled visit, study participants were offered a comprehensive package of prevention services including patient-centered interactive risk-reduction counseling according to the RESPECT (Risk-reduction counseling to prevent human immunodeficiency virus and sexually transmitted diseases) model performed by a peer community member, free condoms and gel, and diagnosis and treatment of sexually transmitted infections (STIs) [9]. Costs of counseling were obtained with a microcosting approach that identified all relevant cost components of the process and valued each for all participants using duration of the procedure, staff and supplies as variables. The total cost of providing counseling was divided by the total number of participants, regardless of their randomization arm. We assumed that if PrEP were to be deployed the counseling would be part of the strategy in addition to the provision of TDF-FTC. Computations for other healthcare costs were based on healthcare resources actually used by participants during the blinded phase of the trial (1 year), including TDF-FTC and the number and type of tests that might be protocol driven, consultations for STIs, or adverse events. Patient-level data on service use was recorded at each visit by the investigators or research assistant based on patients’ medical charts, prescriptions, and the number of remaining pills for TDF-FTC. Nonhealthcare protocol-driven resources (e.g. filling out questionnaires) were excluded. TDF-FTC was valued using manufacturers’ (list) price in France; staff costs for counseling were estimated from gross salaries and supplies from their purchase price by AIDES. Costs of tests and consultations were based on current fees. The unit costs are presented in Table 1. We estimated the entry costs of setting up the program for information purposes but did not include them in the computation of the cost/participant. For base case cost computations, in the placebo arm we assumed a total cost of zero, as all costs incurred by participants were protocol driven. This assumption maximized the cost difference and, therefore, biased the final result against the PrEP arm. A sensitivity analysis was carried out assuming the cost of healthcare in the placebo arm to be equal to the cost of STI tests. All costs were calculated at 2016 prices in € and not discounted because of the 1-year time horizon (€1 = US$1.2).

Table 1

Table 1

Health outcomes for the economic evaluation were measured by the primary clinical end point at 1 year. Study visits were scheduled 4 and 8 weeks after enrollment, and every 8 weeks thereafter. The primary endpoint was HIV-1 infection, defined as the first evidence of HIV antibodies or p24 antigen in serum using of a fourth generation assay or HIV RNA in plasma using a PCR assay.

We estimated the cost of avoiding one infection each year by multiplying the average cost/patient by the number needed to treat (NNT) to avoid one infection. We assumed that each year of PrEP would allow MSMs to avoid infection and that the costs of PrEP accrued yearly for as long as risk exposure remained. The net benefit of PrEP (as a function of time) was, therefore, calculated as the yearly costs of PrEP multiplied by the NNT and by the duration of risk exposure, minus the lifetime cost of HIV infection treatment.

Our methodology was in accordance with the CHEERS statement [10].

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Statistical analysis

Economic analyses were performed for the modified intent to treat population, excluding only data from study participants with HIV-1 infection at enrollment or who were lost to follow-up or withdrew consent between randomization and enrollment and did not receive study medication. We estimated the yearly cost of avoiding one HIV infection using on-demand PrEP and compared it with the yearly and lifetime costs of treating one HIV infection in France which were estimated to be €20 000 and 535 000, respectively [11]. Continuous variables were described using mean ± SD and qualitative variables were described using percentages. Differences in costs were tested using standard parametric or nonparametric tests (Student's or Mann–Whitney's test) as appropriate and were described as means [95% confidence intervals (CIs)]. All P values and CIs are two-sided. The significance level was more than 0.05. The cost difference and 95% CIs were generated using bootstrap with 5000 replications. Univariate sensitivity cost-analyses were performed on drug prices: while the initial base case cost calculations used a drug list price of €500.88/30 tablets, we tested two different drug prices, the generic price in France of €179.9/30 tablets, (generic TDF-FTC has been available since July 2017) and the international market discounted price (Indian generic sold on the internet at €60/30 tablets).

We also tested the effect of the reduction in the number of participants needed to treat (NNT e.g. the number of participants that need to be treated with on-demand PrEP for one of them to avoid HIV infection compared with the controls) based upon the results of PrEP in the Paris populations which had the highest incidence of HIV infection in the IPERGAY trial. A joint comparison of costs and effects was performed by bootstrapping with 5000 resamples.

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Results

Information on resource use was available for 199 participants included in the active (TDF-FTC) arm during the blinded phase of the trial and complete data on drug utilization for 194/199 patients. A total of 16 HIV infections occurred during follow-up, two in the on-demand TDF-FTC group (incidence, 0.91/100 person-years), and 14 in the placebo group (incidence, 6.60/100 person-years), indicating a relative reduction of 86% in the incidence of HIV with TDF-FTC (95% CI: 40–98%, P = 0.0019). The rate of serious adverse events was similar across study groups. The NNT for 1 year to prevent one HIV infection in the total IPERGAY population was 17.6 (95% CI: 10–42).

When considering the participants enrolled in the two Paris sites (total of n = 201 in both arms), 14 HIV infections occurred, two in the on-demand TDF-FTC group (incidence, 1.6/100 person-years), and 12 in the placebo group (incidence = 9.2/100 person-years), indicating a relative reduction of 82% in the incidence of HIV with TDF-FTC (95% CI: 21–98%, P = 0.01). The number of participants needed to treat for 1 year to prevent one HIV infection in the IPERGAY population in Paris was 13.2 (95% CI: 7.6–52.0).

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Resource utilization and costs

The entry costs of providing counseling for all participants included website and information flyers for a total of €11 000. The annual cost of counseling, provided by seven full time equivalents for 400 participants, supplemented by free condoms and gel, came to €690/participant, to which the pre-PrEP workup was added to give a total of €738/participant.

The average use of TDF-FTC/month was 15.6 (SD: 7.23) tablets in the TDF-FTC arm, which was similar to the 15.2 tablets used in the placebo arm. Utilization of healthcare resources and their costs are presented in Tables 2 and 3. There were no hospitalizations in either group.

Table 2

Table 2

Table 3

Table 3

The total 1-year costs of PrEP were €4271 (SD: €2446)/participant, of which 73% were drug costs. The other significant costs were consultations (€205), ELISA tests (€126), and diagnostic for other STIs (€262; Table 2). However, as previously stated in the methodology, the consultations were considered to be entirely protocol driven and thus not included in the total cost.

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Economic evaluation

The yearly cost to avoid one infection calculated as the difference in costs divided by the difference in HIV infections based on trial results of 5.68 HIV infections averted/100 person-years (or 1/NNT) was €75 258/HIV infection averted. As the cost of the placebo arm was set to zero in the base case analysis, the numerator equates to the healthcare costs in the TDF-FTC arm (Table 4).

Table 4

Table 4

Using TDF-FTC at French generic prices (€179.9 for 30 tablets) reduced the 1-year cost of on-demand PrEP to €2271/participant and €39 970/HIV infection averted. Using TDF-FTC at fully discounted international market prices (€60/30 tablets) reduced the 1-year cost of on-demand PrEP to €1517/participant and €26 787/HIV infection averted. The results of the probabilistic sensitivity analysis using the overall NNT of 17.6 to estimate the number of infections averted are presented in Fig. 1a. All replications are in the upper right quadrant, indicating that on-demand PrEP was always more expensive and more effective than no PrEP. The uncertainty of the result was mostly because of the uncertainty of the clinical results, as shown by the length of the scatterplot on the horizontal axis. Because our hypothesis of a zero cost in the placebo arm was conservative (i.e. increased the potential cost difference and therefore the cost/infection averted), we increased the costs in the placebo arm to those of STI tests, or €262/participant and obtained a cost of €70 466/HIV infection averted.

Fig. 1

Fig. 1

The analyses were also run for the participants in the Paris region where the NNT was 13.2 and the results are presented in Fig. 1b. The yearly costs were predictably lower than for the overall population ranging from €58 397 to 20 961/HIV infection averted.

The estimate of the net benefit of using PrEP found that, at current drug prices, PrEP is cost saving up to 7.5 years of risk exposure, up to 13 years of risk exposure at generic price in France and up to 20 years at international market drug prices (Fig. 2).

Fig. 2

Fig. 2

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Discussion

We estimated the total average cost of using on-demand PrEP for high-risk MSM in France based on the results of the IPERGAY double-blind randomized controlled trial. We found that using on-demand PrEP cost on average €75 258 each year to avoid one HIV infection at current drug price and €42 222 at French generic price. From a strictly monetary viewpoint, the use of on-demand PrEP results in a net saving if the duration of the risk exposure is shorter than 7.5 years at current drug price, 13 years at generic price in France today, and 20 years at discounted prices.

Assuming that a decision would be based solely on cost neutrality is incorrect, however, as the health benefits of prevention include reduced transmission, reduced HIV- related morbidity, treatments of other STIs, and psychological benefits.

Our base-case estimate is conservative as we assumed a zero cost in the placebo arm, while MSM may benefit from counseling and testing even in the absence of PrEP. We also used in-trial costs which included laboratory tests which may not occur in routine use of PrEP. We, therefore, maximized the cost difference between PrEP and no PrEP assuming an increment in cost larger than what it may be in reality. This cost difference, however, was driven by the cost of PrEP (drug use and laboratory tests) which was the list price at the time of the trial and which was reduced from €500.88 to 179.9 when the generic became available in July 2017. We also ignored the possibility that avoiding HIV infection in one person may benefit to more than one person. A rapid estimate based on a 2–3 months period for high risk of transmission postinfection [12], with a transmission rate of 0.185/receptive unprotected anal intercourse during that period [13], using the IPERGAY trial results of 14 sexual partners over a 2-month period with an average number of 26 sexual acts out of which 70% were unprotected and a 0.7 probability of having an HIV-negative partner [14], then the expected number of secondary infections during the high infectivity period is 2.36. Using lower figures of transmission/anal intercourse [15,16] would reduce the number of secondary infections to 1.63. To these, other transmissions resulting from secondary infections and occurring before the treatment is initiated could be added. Thus, including in the calculation the cost of treating secondary HIV infections could make on-demand PrEP cost neutral at 1 year in this high-risk population, where the incidence is 6.6 HIV infections/100 person-years. As the cost/infection averted can be roughly estimated by multiplying the 1-year cost of PrEP by the NNT, it can be expected, however, that the net benefit will decrease over time as the incidence of HIV infection decreases. Also, implementing PrEP in a lower risk population might decrease the net benefit of PrEP.

We found that on-demand PrEP resulted in a net monetary benefit for a duration of exposure to risk and need for PrEP of 7.5 years or less at current drug price and 13 years or less at French generic price. Some patients in IPERGAY reported discontinuing the use of PrEP for various reasons including modifications in their sexual behavior. There are no data to date regarding the cumulative lifetime use of PrEP, but such periods without PrEP or avoidance of unprotected anal sex would reduce the overall cost of prophylaxis and increase the net benefit. Also, PrEP has been implemented only recently in high-risk population in France and other countries, and recent report suggest that a reduction in HIV incidence may be foreseen (https://www.gettingtozerosf.org/wp-content/uploads/2017/06/GTZ_Health-Commission_02MAY17_From-HC-website.pdf accessed September 2017).

The IPERGAY trial also found that providing PrEP to MSM allowed the diagnosis and treatment of other STIs which might be otherwise neglected. IPERGAY was not designed to demonstrate this benefit on other STIs as both arms benefited from the same active procedures of detection and treatment but we would argue that the access to on-demand PrEP is an additional tool for the healthcare system to better care for the population of MSM with high levels of sexual risk behaviors. Our economic evaluation was based on infections averted and net benefit because we used in-trial data only and did not extrapolate results. Based on the results of the Preexposure Prophylaxis Initiative (IPrEx) trial, American authors reported costs/infection averted as high as $500 000, or 20 times the cost of treating a person with HIV infection for 1 year but their computations assumed an NNT of 44 which is three times higher than our figures, and double our ‘on-demand’ drug costs [17]. More recently the costs of averting one infection using continued PrEP was estimated at $679 878/infection averted, assuming a 44% reduction in the annual risk of HIV acquisition which is half the IPERGAY results [18]. Translating our results into costs/quality adjusted life years (QALYs) with an NNT of 17.6 and a risk calculator would result in lifetime cost savings [19].

Other authors have reported that taken daily ‘PrEP is unsustainably expensive’ and identified the high cost of the drug as a barrier to the wide adoption of prevention [20]. With TDF-FTC at the current list price the strategy of providing on-demand PrEP, together with counseling and testing other STIs, is nearly four times higher than the cost of treating a patient with HIV infection for 1 year. Using the discounted TDF-FTC costs (€60/30 tablets on the internet, which could become the price of generic TDF-FTC in France in the future), however, PrEP could become cost neutral, which means that the additional drug costs are completely offset by savings at 1 year. The difference in results is explained also by the use of on-demand versus daily PrEP. Although equally effective, on-demand PrEP halved drug costs and appears, therefore, more efficient than systematic PrEP in European countries [6,21]. This would allow using PrEP on a larger population or for a longer duration.

Our calculations included the cost of counseling which is roughly 17% of total costs at the current drug price and 50% at the generic drug price. To further reduce costs, the current protocol could be altered based on the counseling interventions of proven effectiveness.

Compared to other economic evaluations, our results are short term and based on the results of a single trial [7,22]. Most publications on the cost-effectiveness of daily PrEP in MSM have used models to extrapolate the long term of lifetime effects of PrEP. Although this approach fits well the natural history of the disease and the lifetime benefits of not being infected, the uncertainty on the long-term costs and effects is reflected in the wide range of cost-effectiveness ratios, from zero to $1 474 000/QALY [23,24]. A recent modeling of cost-effectiveness of on-demand PrEP in the Netherlands over a 10-year period found a low €2000/QALY, using a yearly cost of on-demand PrEP of €3850, which was less than our cost [6]. These Dutch findings support the use of on-demand PrEP for HIV prevention among MSM. The main political advantage of our trial-based estimates is that they present the more recent estimates given the current situation of HIV incidence, PrEP efficacy and costs and allow policy makers to directly compare the cost of treating HIV infections to the cost of averting HIV infections in France.

Additional evidence on the sustained benefit of on-demand PrEP in a larger population would be useful, although it is not clear that such trials would now be feasible. Strategies based on detection and treatment of HIV infection appear to be insufficient to eradicate HIV and should be complemented by PrEP. Based on IPERGAY data, on-demand PrEP has been approved in France and a generic TDF-FTC has been recently available: further documentation of benefits on HIV infection might be based on large database and analysis of real life data which should be soon available.

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Acknowledgements

We gratefully acknowledge the contribution of Ms Meryl Darlington to the revision of the manuscript.

Ethical approval (CNIL CPP): the protocol was approved by public health authorities and by ethics committees in France (CPP Paris Saint-Louis) and Canada (CER Montreal). All study participants provided written informed consent. The study protocol is available at NEJM.org.

The study was sponsored by the ANRS (France Recherche Nord & Sud Sida-HIV Hépatites) and funded by ANRS, the Canadian HIV Trials Network, the Fonds de dotation Pierre Bergé pour la Prévention – SIDACTION, Gilead Sciences, and the Bill and Melinda Gates Foundation.

Substantial contributions to the conception or design of the work (I.D-Z, J.M. M., C.C., C.T., B.S., G.P., L.M., L.C.); The acquisition, analysis, or interpretation of data for the work (P.M., I.D-Z., I.C., J.C., C.T., C.Ch., L.C., J.M.M., C.Ca., L.M.) and drafting the work or revising it critically for important intellectual content (all); final approval of the version to be published (all); and agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved (all).

I.D-Z. reports receiving support from Pfizer, Janssen, Merck, Abbvie; B.S. reports receiving support as an advisor for Gilead Sciences, Merck, and Janssen, Bristol and research grants from Gilead Sciences and Merck; C.Ch. reports receiving support as an advisor for Gilead, Pfizer, Janssen, and Astellas; C.T. reports receiving support from Gilead Sciences and Pfizer;

J.M.M. reports receiving support as an advisor for Gilead Sciences, Merck, Janssen, Bristol Myers Squib and ViiV, and research grants from Gilead Sciences and Merck; L.C. reports research grants from MSD and ViiV Healthcare and support from AbbVie, Bristol Myers Squib, Gilead Sciences, Janssen, MSD, and ViiV Healthcare.

ANRS IPERGAY Study Group: Members of the Scientific Committee: J.M.M. (Chair), Mark Wainberg, Benoit Trottier, C.T., Jean-Guy Baril, G.P., L.C., Antoine Chéret, Armelle Pasquet, Eric Cua, Michel Besnier, Willy Rozenbaum, C.Ch., Constance Delaugerre, Nathalie Bajos, Julie Timsit, Gilles Peytavin, Julien Fonsart, I.D-Z., L.M., Jean-Pierre Aboulker, B.S., Marie Suzan-Monti, Gabriel Girard, D.R., Marie Préau, Michel Morin, David Thompson, C.Ca., Lucie Marchand, Véronique Doré, Marie-Christine Simon, Isabelle Charreau, Joanne Otis, France Lert, Alpha Diallo, Séverine Gibowski, and Cecile Rabian.

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Conflicts of interest

There are no conflicts of interest.

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References

1. Molina JM, Capitant C, Spire B, Pialoux G, Cotte L, Charreau I, et al. ANRS IPERGAY Study Group. On-demand preexposure prophylaxis in men at high risk for HIV-1 infection. N Engl J Med 2015; 373:2237–2246.
2. FDA. FDA, Press release: FDA approves first drug for reducing the risk of sexually acquired HIV infection [Internet]. Silver Spring: U.S. Food and Drug Administration; 2012. Available from: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm312210.htm. [Accessed September 2017].
3. Hankins C, Macklin R, Warren M. Translating PrEP effectiveness into public health impact: key considerations for decision-makers on cost-effectiveness, price, regulatory issues, distributive justice and advocacy for access. J Int AIDS Soc 2015; 18 (4 Suppl 3):19973.
4. Juusola JL, Brandeau ML, Owens DK, Bendavid E. The cost-effectiveness of preexposure prophylaxis for HIV prevention in the United States in men who have sex with men. Ann Intern Med 2012; 156:541–550.
5. Gomez GB, Borquez A, Case KK, Wheelock A, Vassall A, Hankins C. The cost and impact of scaling up preexposure prophylaxis for HIV prevention: a systematic review of cost-effectiveness modelling studies. PLoS Med 2013; 10:e1001401.
6. Nichols BE, Boucher CA, van der Valk M, Rijnders BJ, van de Vijver DA. Cost-effectiveness analysis of preexposure prophylaxis for HIV-1 prevention in the Netherlands: a mathematical modelling study. Lancet Infect Dis 2016; 16:1423–1429.
7. Ouellet E, Durand M, Guertin JR, LeLorier J, Tremblay CL. Cost effectiveness of ‘on-demand’ HIV preexposure prophylaxis for noninjection drug-using men who have sex with men in Canada. Can J Infect Dis Med Microbiol 2015; 26:23–29.
8. Hellinger FJ. Assessing the cost effectiveness of pre-exposure prophylaxis for HIV prevention in the US. Pharmacoeconomics 2013; 31:1091–1104.
9. Kamb ML, Fishbein M, Douglas JM Jr, Rhodes F, Rogers J, Bolan G, et al. Project RESPECT study group. Efficacy of risk reduction counseling to prevent human immunodeficiency virus and sexually transmitted diseases: a randomized trial. JAMA 1998; 280:1161–1167.
10. Husereau D, Drummond M, Petrou S, Carswell C, Moher D, Greenberg D, et al. ISPOR Health Economic Evaluation Publication Guidelines-CHEERS Good Reporting Practices Task Force. Consolidated Health Economic Evaluation Reporting Standards (CHEERS): explanation and elaboration: a report of the ISPOR Health Economic Evaluation Publication Guidelines Good Reporting Practices Task Force. Value Health 2013; 16:231–250.
11. Sloan CE, Champenois K, Choisy P, Losina E, Walensky RP, Schackmanj BR, et al. Newer drugs and earlier treatment: impact on lifetime cost of care for HIV-infected adults. AIDS 2012; 26:45–56.
12. Hollingsworth TD, Anderson RM, Fraser C. HIV-1 transmission, by stage of infection. J Infect Dis 2008; 198:687–693.
13. Baggaley RF, White RG, Boily MC. HIV transmission risk through anal intercourse: systematic review, meta-analysis and implications for HIV prevention. Int J Epidemiol 2010; 39:1048–1063.
14. Velter A, Barin F, Bouyssou A, Guinard J, Léon L, Le Vu S, et al. HIV prevalence and sexual risk behaviors associated with awareness of HIV status among men who have sex with men in Paris, France. AIDS Behav 2013; 17:1266–1278.
15. Punyacharoensin N, Edmunds WJ, De Angelis D, Delpech V, Hart G, Elford J, et al. Modelling the HIV epidemic among MSM in the United Kingdom: quantifying the contributions to HIV transmission to better inform prevention initiatives. AIDS 2015; 29:339–349.
16. Punyacharoensin N, Edmunds WJ, De Angelis D, Delpech V, Hart G, Elford J, et al. Effect of preexposure prophylaxis and combination HIV prevention for men who have sex with men in the UK: a mathematical modelling study. Lancet HIV 2016; 3:e94–e104.
17. Lee DH, Vielemeyer O. Correspondence: preexposure chemoprophylaxis for HIV prevention. N Engl J Med 2011; 364:1372–1375.
18. Lin F, Farnham PG, Shrestha RK, Mermin J, Sansom SL. Cost effectiveness of HIV prevention interventions in the U.S. Am J Prev Med 2016; 50:699–708.
19. Chen A, Dowdy DW. Clinical effectiveness and cost-effectiveness of HIV preexposure prophylaxis in men who have sex with men: risk calculators for real-world decision-making. PLoS One 2014; 9:e108742.
20. Keller SB, Smith DM. The price of tenofovir-emtricitabine undermines the cost-effectiveness and advancement of preexposure prophylaxis. AIDS 2011; 25:2308–2310.
21. Ong KJ, Desai S, Desai S. Will HIV PrEP given to high-risk MSM in England be cost-effective? Preliminary results of a static decision analytical model. Public Health England Conference, Coventry. 2015
22. Koppenhaver RT, Sorensen SW, Farnham PG, Sansom SL. The cost-effectiveness of preexposure prophylaxis in men who have sex with men in the United States: an epidemic model. J Acquir Immune Defic Syndr 2011; 58:e51–e52.
23. Cambiano V, Miners Al, Phillips A. What do we know about the cost–effectiveness of HIV preexposure prophylaxis, and is it affordable?. Curr Opin HIV AIDS 2016; 11:56–66.
24. Ross EL, Cinti SK, Hutton DW. Implementation and operational research: a cost-effective, clinically actionable strategy for targeting HIV preexposure prophylaxis to high-risk men who have sex with men. J Acquir Immune Defic Syndr 2016; 72:e61–e67.
Keywords:

cost-benefit analysis; economics; HIV; intermittent; MSM; preexposure prophylaxis; prevention

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