Global HIV Incidence Analysis and Implications for Affordability Using Long-Acting Cabotegravir Versus Continuous and Event-Driven Oral Preexposure Prophylaxis

BACKGROUND

The HIV Prevention Trials Network (HPTN) 083/084 trials showed up to 88% increased efficacy of long-acting cabotegravir (CAB-LA) versus continuous oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC). However, CAB-LA's high price limits the number of people who can be treated within fixed prevention budgets. Global human immunodeficiency virus (HIV) prevention budgets are highly limited, with TDF/FTC widely available as a low-cost generic. In randomized clinical trials, event-driven TDF/FTC has shown similar preventive efficacy to continuous TDF/FTC.

METHODS

A systematic review of global HIV incidence studies was conducted. Weighted incidence was calculated in each at-risk population. HIV infection rates were evaluated for 5 prevention strategies, with additional HIV testing, education, and service access costs assumed for each ($18 per person per year). Assumed efficacies were 90% (continuous CAB-LA), 60% (continuous TDF/FTC), and 60% (event-driven TDF/FTC). Using weighted incidence and an assumed 100 000 target population, annual HIV infection rates by population were calculated for each prevention strategy.

RESULTS

Ninety-eight studies in 5 230 189 individuals were included. Incidence per 100 person-years ranged from 0.03 (blood donors) to 3.82 (people who inject drugs). Using the number needed to treat to benefit for each strategy, a mean incidence of 2.6 per 100 person-years in at-risk populations, and a 100 000 target population, current-price continuous CAB-LA cost $949 487 per HIV infection successfully prevented, followed by target-price CAB-LA ($11 453), continuous TDF/FTC ($4231), and event-driven TDF/FTC ($1923).

CONCLUSIONS

High prices of CAB-LA limit numbers treatable within fixed budgets. Low-cost event-driven TDF/FTC consistently prevents the most HIV infections within fixed budgets.

On-Demand Oral Pre-exposure Prophylaxis with Tenofovir/Emtricitabine: What Every Clinician Needs to Know

Based on the results of the IPERGAY study, on-demand HIV pre-exposure prophylaxis (PrEP; also known as "non-daily PrEP," "event-driven PrEP," or "2-1-1 PrEP") is being requested more frequently by patients who have intermittent sexual risk or are unable/unwilling to take daily PrEP; therefore, clinicians will be increasingly required to familiarize themselves with its appropriate use. In this perspective, we summarize data related to on-demand PrEP, describe advantages and disadvantages for this alternative dosing strategy, and provide clinical counseling points.

Acute Trigeminal Neuralgia Associated with Initiation of Emtricitabine/Tenofovir for HIV Pre-Exposure Prophylaxis

HIV pre-exposure prophylaxis (PrEP) with emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) fixed-dose combination (FTC/TDF) is undergoing rapid scale-up in the United States. While FTC/TDF is typically well tolerated, to our knowledge, cranial nerve pathology associated with FTC/TDF has not been previously described. We report the case of a 35-year-old patient who began FTC/TDF PrEP and developed acute trigeminal neuralgia. The neurologic symptoms resolved after treatment discontinuation and recurred upon rechallenge, resulting in permanent discontinuation of PrEP treatment.

Efficacy and safety of switching to dolutegravir plus emtricitabine/tenofovir disoproxil fumarate (TDF) or elvitegravir/cobicistat/emtricitabine/TDF in virologically suppressed HIV-infected patients in clinical practice: results from a multicentre, observational study

OBJECTIVES

The aim of the study was to compare the efficacy and tolerability of switching antiretroviral therapy to dolutegravir + emtricitabine/tenofovir disoproxil fumarate (TDF) with those of switching to elvitegravir/cobicistat/emtricitabine/TDF in clinical practice.

METHODS

In a multicentre real-life observational study, we analysed data for HIV-infected patients on antiretroviral treatment with viral load < 50 HIV-1 RNA copies/mL switching to dolutegravir + emtricitabine/TDF (dolutegravir group) or elvitegravir/cobicistat/emtricitabine/TDF (elvitegravir group). Follow-up was censored at 48 weeks.

RESULTS

The 48-week estimated proportion maintaining virological efficacy was 96.1% with dolutegravir (n = 123) and 95.4% with elvitegravir (n = 186; P = 0.941). Patients in the dolutegravir group showed more treatment discontinuations, but these were mainly as a result of simplification. The elvitegravir group showed more discontinuations because of renal adverse events (2.7% versus 0% with dolutegravir). Interestingly, no difference was observed between the two regimens in central nervous system toxicity-related discontinuations. Switching to dolutegravir was associated with a better blood lipid profile.

CONCLUSIONS

Switching to dolutegravir + emtricitabine/TDF was associated with similar efficacy and tolerability to switching to elvitegravir/cobicistat/emtricitabine/TDF in virologically suppressed patients in clinical practice, although reasons for discontinuation showed differences between regimens. These results should be interpreted with caution, as this is a nonrandomized comparison.

Metabolic Effects of Preexposure Prophylaxis With Coformulated Tenofovir Disoproxil Fumarate and Emtricitabine

Background

Antiretroviral drugs have been associated with changes in lipids, fat mass and dat distribution. Tenofovir disoproxil fumarate (TDF) has been shown to have a more favorable metabolic profile than other drugs in its class. However, the metabolic effects of TDF in preexposure prophylaxis (PrEP) are unknown.

Methods

We evaluated the effects of TDF/emtricitabine (FTC) on lipids and body composition in a blinded, placebo-controlled PrEP trial. Participants enrolled in a metabolic subcohort (N = 251, TDF/FTC; N = 247, placebo) consented to fasting lipid panels, dual-energy X-ray absorptiometry scans for body composition, and pharmacologic testing of drug metabolites at baseline and every 24 weeks thereafter.

Results

Lean body mass was stable and unaffected by TDF/FTC. Body weight increased in both groups but was lower on TDF/FTC through week 72. This difference was explained by lower fat accumulation on TDF/FTC. The net median percent difference (standard error, P value) for TDF/FTC vs placebo at week 24 was -0.8% (0.4%, P = .02), +0.3% (0.4%, P = .46), and -3.8% (1.4%, P = .009) for total, lean, and fat mass, respectively. There was no apparent differential regional fat accumulation on TDF/FTC. Decreases in cholesterol, but not triglycerides, were seen in TDF/FTC participants, with detectable drug levels compared to placebo.

Conclusions

TDF/FTC for PrEP showed cholesterol reductions and appeared to transiently suppress the accumulation of weight and body fat compared to placebo. There was no evidence of altered fat distribution or lipodystrophy during daily oral TDF/FTC PrEP.

Clinical Trials Registration

NCT00458393.

Symptoms, Side Effects and Adherence in the iPrEx Open-Label Extension

BACKGROUND

Blinded clinical trials have reported a modest and transient "start-up syndrome" with initiation of tenofovir-based pre-exposure prophylaxis (PrEP). We evaluate this phenomenon and its effect on adherence in an open-label PrEP study.

METHODS

In the iPrEx open-label extension (OLE) study, an 18-month open-label, multi-site PrEP cohort taking daily oral co-formulated tenofovir/emtricitabine, we examined the prevalence and duration of PrEP-associated symptoms and their effect on adherence, assessed by drug levels in dried blood spots tested monthly for the first 3 months.

RESULTS

Symptom reports peaked within the first month, with 39% reporting potentially PrEP-related symptoms compared to 22% at baseline. Symptoms largely resolved to pre-PrEP levels by 3 months.Symptoms varied substantially in frequency by study site (range in 1-month symptoms: 11% to 70%). Nongastrointestinal (GI) symptoms were not associated with adherence (odds ratio [OR] = 1.2, 95% confidence interval [CI], .4-3.7); however, GI-associated symptoms in the first 4 weeks were inversely associated with adherence at 4 weeks (OR = 0.47, 95% CI, .23-.96). Reports of GI symptoms were associated with 7% (95% CI, 4%-11%) of suboptimal adherence in this cohort.

CONCLUSIONS

PrEP-associated symptoms in the open-label setting occur in a minority of users and largely resolve within 3 months. GI symptoms are associated with a modest reduction in PrEP adherence, but good adherence is possible even in the presence of frequent symptom reports.

CLINICAL TRIALS REGISTRATION

Clinicaltrials.govNCT00458393.

Cost-effectiveness analysis of tenofovir/emtricitabine and abacavir/lamivudine in combination with efavirenz or atazanavir/ritonavir for treatment-naïve adults with HIV-1 infection in the UK, based on the AIDS Clinical Trials Group 5202 clinical trial

OBJECTIVES

The aim of the study was to assess the cost-effectiveness of the four regimens studied in the AIDS Clinical Trials Group (ACTG) 5202 clinical trial, tenofovir/emtricitabine (TDF/FTC) or abacavir/lamivudine (ABC/3TC) in combination with efavirenz (EFV) or atazanavir/ritonavir (ATV/r), for treatment-naïve adults with HIV-1 infection in the UK.

METHODS

A Markov model with six health states based on CD4 cell count ranges was developed to predict long-term costs and health outcomes for individuals on first-line therapy. Head-to-head efficacy data comparing TDF/FTC + EFV, TDF/FTC + ATV/r, ABC/3TC + EFV, and ABC/3TC + ATV/r were obtained from ACTG 5202 for up to 192 weeks. Antiretroviral drug costs were based on current list prices. Other medical costs (2013 UK pounds sterling), utility values, and mortality rates were obtained from published sources. Base-case, sensitivity, and subgroup analyses (by baseline viral load) were conducted.

RESULTS

Individuals using TDF/FTC-based regimens were predicted to remain on first-line therapy longer and accrue more quality-adjusted life-years (QALYs) than individuals using ABC/3TC-based regimens. At a willingness-to-pay threshold of £30 000 per QALY gained, TDF/FTC-based regimens were predicted to be cost-effective compared with ABC/3TC-based regimens, with incremental cost-effectiveness ratios of £23 355 for TDF/FTC + EFV vs. ABC/3TC + EFV and £23 785 for TDF/FTC + ATV/r vs. ABC/3TC + ATV/r. Results were generally robust in subgroup, sensitivity, and scenario analyses.

CONCLUSIONS

In an analysis of the regimens studied in ACTG 5202 for treatment-naïve adults with HIV-1 infection in the UK, TDF/FTC-based regimens yielded more favourable health outcomes and were generally predicted to be cost-effective compared with ABC/3TC-based regimens. These results confirm that TDF/FTC-based regimens are not only clinically effective but also cost-effective.

Translating PrEP effectiveness into public health impact: key considerations for decision-makers on cost-effectiveness, price, regulatory issues, distributive justice and advocacy for access

INTRODUCTION

The extraordinary feat of proving the effectiveness of oral pre-exposure prophylaxis (PrEP) in clinical trials in different populations in a variety of settings may prove to have been easier than ensuring it is used well. Decision-makers must make difficult choices to realize the promise of antiretroviral prophylaxis for their countries. This paper outlines key economic, regulatory and distributive justice issues that must be addressed for effective and acceptable PrEP implementation.

DISCUSSION

In considering the role that PrEP can play in combination prevention programmes, decision-makers must determine who can benefit most from PrEP, how PrEP can be provided safely and efficiently, and what kind of health system support will ensure successful implementation. To do this, they need contextualized information on disease burden by population, analyses of how PrEP services might best be delivered, and projections of the human resource and infrastructure requirements for each potential delivery model. There are cost considerations, varying cost-effectiveness results and regulatory challenges. The principles of ethics can inform thorny discussions about who should be prioritized for oral PrEP and how best to introduce it fairly. We describe the cost-effectiveness of PrEP in different populations at higher risk of HIV exposure, its price in low- and middle-income countries, and the current regulatory situation. We explore the principles of ethics that can inform resource allocation decision-making about PrEP anchored in distributive justice, at a time when universal access to antiretroviral treatment remains to be assured. We then highlight the role of advocacy in moving the PrEP agenda forward.

CONCLUSIONS

The time is ripe now for decisions about whether, how and for whom PrEP should be introduced into a country's HIV response. It has the potential to contribute significantly to high impact HIV prevention if it is tailored to those who can most benefit from it and if current regulatory and pricing barriers can be overcome. Advocacy at all levels can help inform decision-making and push the access agenda to avert HIV infections among those at highest risk of HIV exposure. The benefits will accrue beyond the individual level to slow HIV transmission at the population level.

Strong Correlation Between Concentrations of Tenofovir (TFV) Emtricitabine (FTC) in Hair and TFV Diphosphate and FTC Triphosphate in Dried Blood Spots in the iPrEx Open Label Extension: Implications for Pre-exposure Prophylaxis Adherence Monitoring

Self-reported adherence to pre-exposure prophylaxis (PrEP) has limitations, raising interest in pharmacologic monitoring. Drug concentrations in hair and dried blood spots (DBS) are used to assess long-term-exposure; hair shipment/storage occurs at room temperature. The iPrEx Open Label Extension collected DBS routinely, with opt-in hair collection; concentrations were measured with liquid chromatography/tandem mass spectrometry. In 806 hair-DBS pairs, tenofovir (TFV) hair levels and TFV diphosphate (DP) in DBS were strongly correlated (Spearman coefficient r = 0.734; P < .001), as were hair TFV/DBS emtricitabine (FTC) triphosphate (TP) (r = 0.781; P < .001); hair FTC/DBS TFV-DP (r = 0.74; P < .001); hair FTC/DBS FTC-TP (r = 0.587; P < .001). Drug detectability was generally concordant by matrix. Hair TFV/FTC concentrations correlate strongly with DBS levels, which are predictive of PrEP outcomes.