Comparative Pricing of Branded Tenofovir Alafenamide-Emtricitabine Relative to Generic Tenofovir Disoproxil Fumarate-Emtricitabine for HIV Preexposure Prophylaxis: A Cost-Effectiveness Analysis

Integrated PrEP and STI Services for Transgender Women in Uganda: Qualitative Findings from a Randomized Trial

Tenofovir alafenamide fumarate (F/TAF) pre-exposure prophylaxis (PrEP) is understudied in sub-Saharan Africa. The Tandika PrEP study was a randomized trial that evaluated same-day F/TAF initiation, the impact of drug-level feedback on PrEP adherence, and integrated PrEP and sexually transmitted infection (STI) services for HIV-negative transgender women (TGW) in Uganda (NCT04491422). From April 2022-February 2023, a qualitative sub-study of 30 in-depth interviews explored (1) perspectives on same-day initiation of F/TAF PrEP, (2) experiences of urine tenofovir testing and drug-level feedback, and (3) descriptions of self-collection of samples for STI testing. Qualitative data were analyzed using an inductive content analytic approach. Integrated PrEP/STI services were valued by TGW because the convenience of urine testing motivated adherence and allowed for tenofovir and STI detection. (1) Preferred characteristics: F/TAF-based PrEP was easy to take and not readily identifiable as an HIV-related medication, resulting in less stigma than the better-known tenofovir disoproxil fumarate (F/TDF). Weight gain associated with F/TAF use was viewed positively by TGW as a symbol of health and prosperity in African settings. (2) Adherence motivation: PrEP adherence was motivated by a desire not to disappoint healthcare workers; TGW reciprocated adherence support and drug-level feedback by taking PrEP. (3) Facilitating adherence and STI care: Urine testing enhanced STI detection and treatment. Utilization of urine for tenofovir and STI testing motivated the uptake of HIV/STI care, emphasizing the importance of integrated PrEP and STI services. Integrating PrEP/STI services into differentiated delivery models could increase prevention uptake in this vulnerable population.

Cost-effectiveness of Cabotegravir Long-Acting for HIV Pre-exposure Prophylaxis in the United States

OBJECTIVE

Cabotegravir long-acting (CAB-LA) administered every 2 months was approved in the USA as pre-exposure prophylaxis (PrEP) for individuals at risk of acquiring human immunodeficiency virus (HIV)-1 infection based on the HIV Prevention Trials Network (HPTN) 083 and HPTN 084 clinical trials, which demonstrated superior reduction in HIV-1 acquisition compared with daily oral emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) in men who have sex with men (MSM), transgender women (TGW), and cisgender women. A decision-analytic model was developed to assess the lifetime cost-effectiveness of initiating CAB-LA versus generic oral FTC/TDF for HIV PrEP in the USA from a healthcare sector perspective.

METHODS

PrEP-eligible adults entered the Markov model receiving CAB-LA or FTC/TDF and could continue initial PrEP, transition to a second PrEP option, or discontinue PrEP over time. Efficacy was taken from the HPTN 083 and HPTN 084 clinical trials. Individuals who acquired HIV-1 infection incurred lifetime HIV-related costs, could transmit HIV onwards, and could develop PrEP-related resistance mutations. Input parameter values were obtained from public and published sources. Model outcomes were discounted at 3%.

RESULTS

The model estimated that the CAB-LA pathway prevented 4.5 more primary and secondary HIV-1 infections per 100 PrEP users than the oral PrEP pathway, which yielded 0.2 fewer quality-adjusted life-years (QALYs) lost per person. Additional per-person lifetime costs were $9476 (2022 US dollars), resulting in an incremental cost-effectiveness ratio of $46,843 per QALY gained. Results remained consistent in sensitivity and scenario analyses, including in underserved populations with low oral PrEP usage.

CONCLUSIONS

Our analysis suggests that initiating CAB-LA for PrEP is cost-effective versus generic daily oral FTC/TDF for individuals at risk of acquiring HIV-1 infection.

Trends in HIV preexposure prophylaxis utilization and spending among individuals with commercial insurance

In a cross-sectional analysis of HIV preexposure prophylaxis (PrEP) utilization by commercially insured patients from 2019 to 2021, most prescriptions were for branded formulations of PrEP despite the availability of a generic version. Accounting for the modest relative clinical benefit of branded TAF/FTC (tenofovir alafenamide fumarate/emtricitabine) PrEP over generic TDF/FTC (tenofovir disoproxil fumarate/emtricitabine) PrEP, use of generic TDF/FTC PrEP would have reduced commercial insurers' spending by 33%.

Broadening access to tenofovir alafenamide for the treatment and prevention of HIV-1 infection

INTRODUCTION

Tenofovir alafenamide (TAF), a prodrug of tenofovir, achieves higher intracellular concentrations of tenofovir-diphosphate and 90% lower plasma concentrations of tenofovir compared to tenofovir disoproxil fumarate (TDF). TAF is associated with improved renal and bone safety outcomes.

AREAS COVERED

We review the efficacy and safety of TAF-containing regimens in adults and pediatrics. We highlight safety data during pregnancy, drug interactions during co-administration with tuberculosis treatment, and critical knowledge gaps to be addressed for the successful implementation of TAF in low- and middle-income countries. We performed a search on MEDLINE PubMed and conference websites for relevant articles published from January 2010 to March 2023.

EXPERT OPINION

Current evidence demonstrates that TAF has similar efficacy and tolerability, superior bone and renal safety, and higher rates of dyslipidemia and weight gain, compared with TDF. However, there are several knowledge gaps, in specific sub-populations, that require action. Emerging data suggests that TAF is safe during pregnancy, although fuller safety data to support TAF use in pregnancy is needed. Similarly, there is a lack of evidence that TAF can be used in combination with rifamycin-based tuberculosis treatment in PWH and TB. Further studies are needed to fill knowledge gaps and support the wider rollout of TAF.

Costs and Cost-Effectiveness of Biomedical, Non-Surgical HIV Prevention Interventions: A Systematic Literature Review

BACKGROUND

Considerable evidence on the costs and cost-effectiveness of biomedical, non-surgical interventions to prevent human immunodeficiency virus (HIV) transmission has been generated over the last decade. This study aims to synthesize findings and identify remaining knowledge gaps to suggest future research priorities.

METHODS

A systematic literature review was carried out in August 2020 using the MEDLINE, Embase, Global Health and EconLit databases to retrieve economic evaluations and costing studies of oral pre-exposure prophylaxis (PrEP), injectable long-acting PrEP, vaginal microbicide rings and gels, HIV vaccines and broadly neutralizing antibodies. Studies reporting costs from the provider or societal perspective were included in the analysis. Those reporting on behavioural methods of prevention, condoms and surgical approaches (voluntary medical male circumcision) were excluded. The quality of reporting of the included studies was assessed using published checklists.

RESULTS

We identified 3007 citations, of which 87 studies were retained. Most were set in low- and middle-income countries (LMICs; n = 53) and focused on the costs and/or cost-effectiveness of oral PrEP regimens (n = 70). Model-based economic evaluations were the most frequent study design; only two trial-based cost-effectiveness analyses and nine costing studies were found. Less than half of the studies provided practical details on how the intervention would be delivered by the health system, and only three of these, all in LMICs, explicitly focused on service integration and its implication for delivery costs. 'Real-world' programme delivery mechanisms and costs of intervention delivery were rarely considered. PrEP technologies were generally found to be cost-effective only when targeting high-risk subpopulations. Single-dose HIV vaccines are expected to be cost-effective for all groups despite substantial uncertainty around pricing.

CONCLUSIONS

A lack of primary, detailed and updated cost data, including above-service level costs, from a variety of settings makes it difficult to evaluate the cost-effectiveness of specific delivery modes at scale, or to evaluate strategies for services integration. Closing this evidence gap around real-world implementation is vital, not least because the strategies targeting high-risk groups that are recommended by PrEP models may incur substantially higher costs and be of limited practical feasibility in some settings.

Medicaid Spending on Antiretrovirals From 2007 Through 2019

BACKGROUND

Antiretroviral (ARV) medications to treat human immunodeficiency virus (HIV) are a major contributor to Medicaid prescription drug spending. Despite having been used for over 3 decades, the first generic ARVs only recently became available, and many newer versions continue to be sold at high prices despite within-class competition. We estimated Medicaid spending on ARVs from 2007 through 2019.

METHODS

Using public Medicaid State Drug Utilization data, we identified trends in ARV spending and use from 2007 through 2019. We estimated net spending and average prices (spending per 30-day supply), accounting for statutory Medicaid rebates, including a 15%-23% base rebate plus additional rebates if a drug's price increased faster than inflation.

RESULTS

Among 48 ARVs, estimated net Medicaid spending from 2007 through 2019 was $25 billion for 17 million 30-day supplies. Annual use increased 118%, from 0.7 million 30-day supplies in 2007 to 1.6 million in 2019. During this time, estimated annual net spending increased 178%, from $1.1 billion to $3.0 billion, and average net prices increased 28%, from $1432 to $1830 per 30-day supply.

CONCLUSIONS

Annual Medicaid net spending on ARVs nearly tripled from 2007 to 2019, due to a combination of expanded use and rising prices. Medicaid did not extract expected benefits from its mandatory inflationary rebates because they were offset by use of newer, more expensive ARVs. To better control spending related to products with incremental innovation, the US government should be authorized to assure that launch prices for new drugs are aligned with the added benefit they offer over existing therapies.

Overcoming structural barriers to diffusion of HIV pre-exposure prophylaxis

HIV prevention with antiretroviral medication in the form of pre-exposure prophylaxis (PrEP) offers a critical tool to halt the HIV pandemic. Barriers to PrEP access across drug types, formulations, and delivery systems share remarkable commonalities and are likely to be generalizable to future novel PrEP strategies. Appreciation of these barriers allows for planning earlier in the drug-development pathway rather than waiting for the demonstration of efficacy. The purpose of this article is to propose a core set of considerations that should be included in the drug-development process for future PrEP interventions. A literature synthesis of key barriers to PrEP uptake in the United States was conducted to elucidate commonalities across PrEP agents and delivery methods. Based on the published literature, we divided challenges into three main categories of structural barriers: (1) provider and clinic characteristics; (2) cost considerations; and (3) disparities and social constructs, with potential solutions provided for each. Pragmatic strategies for examining and overcoming these barriers before future PrEP regulatory approval are recommended. If these strategies are considered well before the time of commercial availability, the potential for PrEP to interrupt the HIV pandemic will be greatly enhanced.

Paying for PrEP: A qualitative study of cost factors that impact pre-exposure prophylaxis uptake in the US

BACKGROUND

Concerns about the actual and perceived costs of pre-exposure prophylaxis (PrEP) continue to be a major barrier to uptake among gay, bisexual and men who have sex with men (GBMSM) in the United States.

METHODS

We conducted semi-structured interviews with 25 GBMSM who presented for routine health care at a STD clinic in the northeastern United States. The cohort included GBMSM who were or were not currently taking PrEP and represented varied health care coverage and financial resources. We used a structured coding scheme to analyze transcripts and identify themes relevant to cost factors.

RESULTS

Participants shared their perspectives about PrEP and their experiences with accessing and paying for PrEP. Our findings suggest that health care coverage or financial assistance were essential to PrEP access but were not easily accessible to all people and did not always cover all costs. Therefore, paying for PrEP had to be balanced with other life expenses. Participants had multiple sources for information about PrEP cost and assistance from clinic and pharmacy staff helped reduce burden and resolve difficulties.

CONCLUSION

Addressing gaps in health care coverage, providing financial support, and improving the enrollment process in a financial assistance program may improve PrEP uptake.

Estimated changes in price discounts for tenofovir-inclusive HIV treatments following introduction of tenofovir alafenamide

We estimated list and net prices for tenofovir disoproxil fumarate (TDF) products Truvada, Complera, and Stribild, and their tenofovir alafenamide (TAF) versions Descovy, Odefsey, and Genvoya. Gilead offered discounts for Descovy that resulted into lower net prices compared to Truvada. This strategy encouraged patients switching from Truvada to Descovy before the availability of generic Truvada. Conversely, Gilead offered lower discounts for Odefsey and Genvoya, which resulted into higher net prices compared to Complera and Stribild.

Data Velocity in HIV-Related Implementation Research: Estimating Time From Funding to Publication

BACKGROUND

Given available effective biomedical and behavioral prevention and treatment interventions, HIV-related implementation research (IR) is expanding. The rapid generation and dissemination of IR to inform guidelines and practice has the potential to optimize the impact of the Ending the Epidemic Initiative and the HIV pandemic response more broadly.

METHODS

We leveraged a prior mapping review of NIH-funded awards in HIV and IR from January 2013 to March 2018 and identified all publications linked to those grants in NIH RePORTER through January 1, 2021 (n = 1509). Deduplication and screening of nonoriginal research reduced the count to 1032 articles, of which 952 were eligible and included in this review. Publication volume and timing were summarized; Kaplan-Meier plots estimated time to publication.

RESULTS

Among the 215 NIH-funded IR-related awards, 127 of 215 (59%) published original research directly related to the grant, averaging 2.0 articles (SD: 3.3) per award, largely in the early IR phases. Many articles (521 of 952, 55%) attributed to grants did not report grant-related data. Time from article submission to publication averaged 205 days (SD: 107). The median time-to-first publication from funding start was 4 years. Data dissemination velocity varied by award type, trending toward faster publication in recent years. Delays in data velocity included (1) time from funding to enrollment, (2) enrollment length, and (3) time from data collection completion to publication.

CONCLUSION

Research publication was high overall, and time-to-publication is accelerating; however, over 40% of grants have yet to publish findings from grant-related data. Addressing bottlenecks in the production and dissemination of HIV-related IR would reinforce its programmatic and policy relevance in the HIV response.

Cost-Effectiveness of Pre-exposure Prophylaxis Among Men Who Have Sex With Men in China: A Systematic Review

Objective

Men who have sex with men in China meet the definition of the population at “substantial risk” of contracting human immunodeficiency virus (HIV) according to the World Health Organization; therefore, initiating pre-exposure prophylaxis (PrEP) is recommended for this population. Lack of convincing evidence on cost-effectiveness has resulted in the lack of large-scale PrEP implementation at a national level. The objective of this review is to assess the cost-effectiveness of pre-exposure prophylaxis implementation among men who have sex with men in China.

Methods

The following databases were used to search studies of pre-exposure prophylaxis in China in both English and Chinese: PubMed, Embase, the China National Knowledge Infrastructure (CNKI), and the Wanfang Database. Inclusion criteria included pre-exposure intervention, year for publication (2007–2021), setting (China), and cost-effectiveness estimation.

Results

Seven studies were identified. We found that pre-exposure prophylaxis is only cost-effective among men who have sex with men without prioritization with at least a 5.5% reduction in the market price in the models. Pre-exposure prophylaxis is potentially cost-effective when using the latest market price, combined with other preventive programs or delivered to the population with a high risk of HIV exposure.

Conclusion

Our study identifies key considerations in cost-effectiveness evaluation: cost assumptions, implementation coverage, and targeted population. The scarce evidence available is not comparable to some extent. However, combined with the latest market and policy reform, the cost-effectiveness of PrEP could be achieved as estimated by the underlying model of the included studies. Consequently, it calls for more standard and transparent modeling studies that include the latest drug types and market prices.

Cost-Effectiveness of Long-Acting Injectable HIV Preexposure Prophylaxis in the United States : A Cost-Effectiveness Analysis

BACKGROUND

The HIV Prevention Trials Network (HPTN) 083 trial demonstrated the superiority of long-acting injectable cabotegravir (CAB-LA) compared with oral emtricitabine-tenofovir disoproxil fumarate (F/TDF) for HIV preexposure prophylaxis (PrEP).

OBJECTIVE

To identify the maximum price premium (that is, greatest possible price differential) that society should be willing to accept for the additional benefits of CAB-LA over tenofovir-based PrEP among men who have sex with men and transgender women (MSM/TGW) in the United States.

DESIGN

Simulation, cost-effectiveness analysis.

DATA SOURCES

Trial and published data, including estimated HIV incidence (5.32, 1.33, and 0.26 per 100 person-years for off PrEP, generic F/TDF and branded emtricitabine-tenofovir alafenamide (F/TAF), and CAB-LA, respectively); 28% 6-year PrEP retention. Annual base-case drug costs: $360 and $16 800 for generic F/TDF and branded F/TAF. Fewer side effects with branded F/TAF versus generic F/TDF were assumed.

TARGET POPULATION

476 700 MSM/TGW at very high risk for HIV (VHR).

TIME HORIZON

10 years.

PERSPECTIVE

Health care system.

INTERVENTION

CAB-LA versus generic F/TDF or branded F/TAF for HIV PrEP.

OUTCOME MEASURES

Primary transmissions, quality-adjusted life-years (QALYs), costs (2020 U.S. dollars), incremental cost-effectiveness ratios (ICERs; U.S. dollars per QALY), maximum price premium for CAB-LA versus tenofovir-based PrEP.

RESULTS OF BASE-CASE ANALYSIS

Compared with generic F/TDF (or branded F/TAF), CAB-LA increased life expectancy by 28 000 QALYs (26 000 QALYs) among those at VHR. Branded F/TAF cost more per QALY gained than generic F/TDF compared with no PrEP. At 10 years, CAB-LA could achieve an ICER of at most $100 000 per QALY compared with generic F/TDF at a maximum price premium of $3700 per year over generic F/TDF (CAB-LA price <$4100 per year).

RESULTS OF SENSITIVITY ANALYSIS

In a PrEP-eligible population at high risk for HIV, rather than at VHR (n = 1 906 800; off PrEP incidence: 1.54 per 100 person-years), CAB-LA could achieve an ICER of at most $100 000 per QALY versus generic F/TDF at a maximum price premium of $1100 per year over generic F/TDF (CAB-LA price <$1500 per year).

LIMITATION

Uncertain clinical and economic benefits of averting future transmissions.

CONCLUSION

Effective oral PrEP limits the additional price society should be willing to pay for CAB-LA.

PRIMARY FUNDING SOURCE

FHI 360; Eunice Kennedy Shriver National Institute of Child Health and Human Development; National Institute of Allergy and Infectious Diseases; National Heart, Lung, and Blood Institute; National Institute on Drug Abuse; the Reich HIV Scholar Award; and the Steve and Deborah Gorlin MGH Research Scholars Award.

Financing and Delivering Pre-Exposure Prophylaxis (PrEP) to End the HIV Epidemic

The U.S. has the tools to end the HIV epidemic, but progress has stagnated. A major gap in U.S. efforts to address HIV is the under-utilization of medications that can virtually eliminate acquisition of the virus, known as pre-exposure prophylaxis (PrEP). This document proposes a financing and delivery system to unlock broad access to PrEP for those most vulnerable to HIV acquisition and bring an end to the HIV epidemic.

Opportunities and Challenges of Generic Pre-Exposure Prophylaxis Drugs for HIV

Antiretroviral pre-exposure prophylaxis (PrEP) is protective against HIV. Low utilization rates amongst HIV vulnerable populations are due in part to the high cost of PrEP. Generic PrEP offers the potential to improve health at significantly reduced costs. In this study, we examine early utilization patterns and prices for generic PrEP. We discuss the opportunities and challenges for generic PrEP to improve health among HIV vulnerable populations.

Prescribing rates and characteristics of recipients of tenofovir-containing regimens before and after market entry of tenofovir alafenamide

BACKGROUND: Tenofovir alafenamide (TAF) is a new formulation of tenofovir disoproxil fumarate (TDF) that was approved in 2015. While clinical trial evidence suggests that TAF has more favorable outcomes related to kidney injury and loss of bone mineral density, TAF also leads to higher lipid levels compared with TDF. OBJECTIVES: To (a) determine prescribing rates of TDF and TAF among new recipients from 2014 to 2018 in a large academic health system and (b) compare baseline patient characteristics of those newly prescribed TDF versus TAF before and after the approval of TAF in November 2015. METHODS: Electronic health record data were used to identify new recipients of TDF or TAF from 2014 to 2018 and describe their total monthly TDF and TAF prescriptions by indication. Patient characteristics were compared among new recipients of TDF before November 2015, new recipients of TDF after November 2015, and new recipients of TAF. RESULTS: Monthly TAF prescribing rates increased to match TDF prescribing rates by April 2018 (82 vs. 88 prescriptions per month). TAF recipients and new recipients of TDF before November 2015 had similar racial distributions; both of these groups were more likely to be Black compared with new recipients of TDF after November 2015 (55% and 53% vs. 37%; P < 0.0001). TAF recipients also tended to have more comorbidities, including chronic kidney disease (7% vs. 2% and 2%; P < 0.0001), hepatitis C virus (8% vs. 5% and 3%; P < 0.0001), diabetes (13% vs. 5% and 6%; P < 0.0001), hypertension (27% vs. 13% and 13%; P < 0.0001), coronary artery disease (5% vs. 3% and 2%; P < 0.0001), hyperlipidemia (21% vs. 6% and 7%; P < 0.0001), and congestive heart failure (3% vs. 1% and 1%; P < 0.0001), compared with both new recipients of TDF before and after November 2015. CONCLUSIONS: TAF prescribing rates grew substantially in the 2.5 years after FDA approval. TAF is being prescribed more often than TDF in patients with chronic kidney disease and in patients with cardiovascular disease, suggesting that prescribers may be prioritizing the kidney safety profile over the effect on lipids. DISCLOSURES: This work was supported by the Duke Clinical Research Institute Executive Director's Pathway for Supplemental Funding. The research team received additional support from the National Institute of Diabetes, Digestive, and Kidney Disease R01DK112258 and P01DK056492 (CW) and from the National Institute of Allergy and Infectious Diseases 5T32AI100851 (MHM). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Hung reports past employment by Blue Cross Blue Shield Association and CVS Health and a grant from Pharmaceutical Research and Manufacturers of America (PhRMA), unrelated to this work. The other authors have nothing to disclose. This work was accepted as a poster presentation for the AMCP Nexus 2020 Virtual, October 19-23, 2020.

Why Are Patients Switching from Tenofovir Disoproxil Fumarate/Emtricitabine (Truvada) to Tenofovir Alafenamide/Emtricitabine (Descovy) for Pre-Exposure Prophylaxis?

Safety differences between tenofovir alafenamide/emtricitabine (TAF) and tenofovir disoproxil fumarate/emtricitabine (TDF/FTC)-formulated pre-exposure prophylaxis (PrEP) appear to have little clinical significance for most PrEP users. Furthermore, generic TDF-formulated PrEP is projected to decrease the price of PrEP. Thus, efforts to shift PrEP users to TAF-formulated PrEP should be considered in light of their potential to undermine efforts to scale-up PrEP nationally. Data are taken from Together 5,000, a US national cohort study predominantly composed of cisgender gay and bisexual men. In 2019-2020, 5034 participants completed their 24-month assessment, which measured whether participants were switching from TDF (Truvada) to TAF (Descovy) for PrEP, and why. Of those reporting PrEP-use (n = 1009), 277 reported using Descovy for PrEP, and 223 provided a reason for switching to Descovy. A content analysis was used to code participant's reasons for switching. Over half (56%) of participants reported that their doctor recommended switching to Descovy. Without mentioning a provider recommendation, 32% of participants reported that perceived improved safety of Descovy, compared with Truvada, motivated their decision to change their prescription. Other factors cited included the smaller size of the pill and "newness" of Descovy. Further, several participants mentioned negative advertising about Truvada as rationale for switching. Although scientific consensus supports the safety of both TDF/FTC and TAF, our results suggest that current messaging through physicians and other sources have emphasized superior safety of TAF-implying that TDF/FTC may not be safe in the long term. Efforts to shift users onto TAF may undermine public perception of TDF-formulated PrEP.

A decision analytics model to optimize investment in interventions targeting the HIV preexposure prophylaxis cascade of care

OBJECTIVES

Gaps between recommended and actual levels of HIV preexposure prophylaxis (PrEP) use remain among MSM. Interventions can address these gaps but it is unknown how public health initiatives should invest prevention funds into these interventions to maximize their population impact.

DESIGN

We used a stochastic network-based HIV transmission model for MSM in the Atlanta area paired with an economic budget optimization model.

METHODS

The model simulated MSM participating in up to three real-world PrEP cascade interventions designed to improve initiation, adherence, or persistence. The primary outcome was infections averted over 10 years. The budget optimization model identified the investment combination under different budgets that maximized this outcome, given intervention costs from a payer perspective.

RESULTS

From the base 15% PrEP coverage level, the three interventions could increase coverage to 27%, resulting in 12.3% of infections averted over 10 years. Uptake of each intervention was interdependent: maximal use of the adherence and persistence interventions depended on new PrEP users generated by the initiation intervention. As the budget increased, optimal investment involved a mixture of the initiation and persistence interventions but not the adherence intervention. If adherence intervention costs were halved, the optimal investment was roughly equal across interventions.

CONCLUSION

Investments into the PrEP cascade through initiatives should account for the interactions of the interventions as they are collectively deployed. Given current intervention efficacy estimates, the total population impact of each intervention may be improved with greater total budgets or reduced intervention costs.

Mathematical Modelling of the Molecular Mechanisms of Interaction of Tenofovir with Emtricitabine against HIV

The combination of the two nucleoside reverse transcriptase inhibitors (NRTI) tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) is used in most highly active antiretroviral therapies for treatment of HIV-1 infection, as well as in pre-exposure prophylaxis against HIV acquisition. Administered as prodrugs, these drugs are taken up by HIV-infected target cells, undergo intracellular phosphorylation and compete with natural deoxynucleoside triphosphates (dNTP) for incorporation into nascent viral DNA during reverse transcription. Once incorporated, they halt reverse transcription. In vitro studies have proposed that TDF and FTC act synergistically within an HIV-infected cell. However, it is unclear whether, and which, direct drug–drug interactions mediate the apparent synergy. The goal of this work was to refine a mechanistic model for the molecular mechanism of action (MMOA) of nucleoside analogues in order to analyse whether putative direct interactions may account for the in vitro observed synergistic effects. Our analysis suggests that depletion of dNTP pools can explain apparent synergy between TDF and FTC in HIV-infected cells at clinically relevant concentrations. Dead-end complex (DEC) formation does not seem to significantly contribute to the synergistic effect. However, in the presence of non-nucleoside reverse transcriptase inhibitors (NNRTIs), its role might be more relevant, as previously reported in experimental in vitro studies.

Evaluating the combination of emtricitabine/ tenofovir alafenamide fumarate to reduce the risk of sexually acquired HIV-1-infection in at-risk adults

INTRODUCTION

Pre-exposure prophylaxis with a single daily pill of emtricitabine (F) plus tenofovir disoproxil fumarate (TDF) is highly efficacious at preventing HIV acquisition. Tenofovir alafenamide (TAF) is another tenofovir prodrug that delivers higher intracellular levels of active tenofovir diphosphate in blood cells and has an improved safety profile compared to TDF. Given the recent regulatory approval of the F/TAF combination for prophylaxis, it is important to review its safety and efficacy.

AREAS COVERED

In this review, the author examines the safety and efficacy of F/TAF for pre-exposure prophylaxis. Both published manuscripts and conference papers are reviewed. F/TAF is non-inferior to F/TDF at preventing HIV acquisition in men and transgender women with a trend toward superiority. F/TAF has yet to be tested against HIV exposure via injection or vaginal intercourse.

EXPERT OPINION

Within these limitations, F/TAF may be particularly advantageous for older individuals thanks to improved kidney safety compared to F/TDF. F/TAF did not possess the hypolipidemic properties of F/TDF and was associated with weight gains.

National Trends in Drug Payments for HIV Preexposure Prophylaxis in the United States, 2014 to 2018 : A Retrospective Cohort Study

BACKGROUND

Use of HIV preexposure prophylaxis (PrEP) has increased nationwide, but the magnitude and distribution of PrEP medication costs across the health care system are unknown.

OBJECTIVE

To estimate out-of-pocket (OOP) and third-party payments using a large pharmacy database.

DESIGN

Retrospective cohort study.

SETTING

Prescriptions for tenofovir disoproxil fumarate with emtricitabine (TDF-FTC) for PrEP in the United States in the IQVIA Longitudinal Prescriptions database, which covers more than 90% of retail pharmacy prescriptions.

MEASUREMENTS

Third-party, OOP, and total payments were compared by third-party payer, classified as commercial, Medicaid, Medicare, manufacturer assistance program, or other. Missing payment data were imputed using a generalized linear model to estimate overall PrEP medication payments.

RESULTS

Annual PrEP prescriptions increased from 73 739 to 1 100 684 during 2014 to 2018. Over that period, the average total payment for 30 TDF-FTC tablets increased from $1350 to $1638 (5.0% compound annual growth rate) and the average OOP payment increased from $54 to $94 (14.9% compound annual growth rate). Of the $1638 in total payments per 30 TDF-FTC tablets in 2018, OOP payments accounted for $94 (5.7%) and third-party payments for $1544 (94.3%). Out-of-pocket payments per 30 tablets were lower among Medicaid recipients ($3) than among those with Medicare ($80) or commercial insurance ($107). Payments for PrEP medication in the IQVIA database in 2018 totaled $2.08 billion; $1.68 billion (80.7%) originated from prescriptions for persons with commercial insurance, $200 million (9.6%) for those with Medicaid, $48 million (2.3%) for those with Medicare, and $127 million (6.1%) for those with manufacturer assistance.

LIMITATION

The IQVIA database does not capture every prescription nationwide.

CONCLUSION

Third-party and OOP payments per 30 TDF-FTC tablets increased annually. The $2.08 billion in PrEP medication payments in 2018 is an underestimation of national costs. High costs to the health care system may hinder PrEP expansion.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.