Atazanavir plus ritonavir or saquinavir, and lopinavir/ritonavir in patients experiencing multiple virological failures

Insights into gastrointestinal manifestation of human immunodeficiency virus: A narrative review

Human immunodeficiency virus (HIV) modifies CD4-positive cells, resulting in immunodeficiency and a wide range of gastrointestinal (GI) manifestations. The burden of HIV-related GI illnesses has significantly evolved with the widespread use of antiretroviral therapy (ART). While ART has effectively reduced the occurrence of opportunistic infections, it has led to an increase in therapy-related GI illnesses. Common esophageal conditions in HIV patients include gastroesophageal reflux disease, idiopathic esophageal ulcers, herpes simplex virus, cytomegalovirus (CMV), and candidal esophagitis. Kaposi's sarcoma, a hallmark of acquired immunodeficiency syndrome, may affect the entire GI system. Gastritis and peptic ulcer disease are also frequently seen in patients with HIV. Diarrhea, often linked to both opportunistic infections and ART, requires careful evaluation. Bloody diarrhea, often a sign of colitis caused by bacterial infections such as Shigella or Clostridium difficile, is prevalent. Small bowel lymphoma, although rare, is increasing in prevalence. Anorectal disorders, including proctitis, fissures, and anal squamous cell carcinoma, are particularly relevant in homosexual men, underlining the importance of timely diagnosis. This review comprehensively explores the epidemiology, pathogenesis, and treatment considerations for the various GI disorders associated with HIV, highlighting the importance of accurate diagnosis and effective treatment to improve outcomes for HIV-infected patients.

Atazanavir / ritonavir versus Lopinavir / ritonavir-based combined antiretroviral therapy (cART) for HIV-1 infection: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis was conducted to evaluate the safety and effectiveness of Atazanavir/ritonavir over lopinavir/ritonavir in human immunodeficiency virus-1 (HIV-1) infection.

METHODS

Clinical trials with a head-to-head comparison of atazanavir/ritonavir and lopinavir/ritonavir in HIV-1 were included. Electronic databases: PubMed/Medline CENTRAL, Embase, Scopus, and Web of Science were searched. Viral suppression below 50 copies/ml at the longest follow-up period was the primary outcome measure. Grade 2-4 treatment-related adverse drug events, lipid profile changes and grade 3-4 bilirubin elevations were used as secondary outcome measures.

RESULTS

A total of nine articles from seven trials with 1938 HIV-1 patients were included in the current study. Atazanavir/ritonavir has 13% lower overall risk of failure to suppress the virus level < 50 copies/ml than lopinavir/ritonavir in fixed effect model (pooled RR: 0.87; CI: 0.78, 0.96; P=0.006). The overall risk of hyperbilirubinemia is very high for atazanavir/ritonavir than lopinavir/ritonavir in the random effects model (pooled RR: 45.03; CI: 16.03, 126.47; P< 0.0001).

CONCLUSION

Atazanavir/ritonavir has a better viral suppression at lower risk of lipid abnormality than lopinavir/ritonavir. The risk and development of hyperbilirubinemia from atazanavir-based regimens should be taken into consideration both at the time of prescribing and patient follow-up.

A first-in-human, randomized, double-blind, placebo-controlled, single and multiple ascending oral dose study to assess the safety, tolerability, and pharmacokinetics of BZF961 with and without ritonavir in healthy adult volunteers

Objective: Infection with hepatitis C virus is the leading indication for liver transplantation and most common cause of infectious disease-related mortality in the United States. BZF961 is a novel inhibitor of the hepatitis C virus NS3-4A protease. Methods: This sequential, three part exploratory first-in-human study investigated the safety and pharmacokinetics of single and multiple ascending oral doses of BZF961 in healthy subjects. The first two parts were randomized, double-blind, placebo-controlled, time-lagged, single and multiple ascending oral dose segments. The third part analyzed the effect of ritonavir on BZF961 pharmacokinetics. Results: BZF961 was generally safe and well-tolerated in single and multiple oral doses in healthy subjects. There were no deaths and no serious adverse events. The most common adverse events were nausea and other gastrointestinal symptoms. Co-administration of ritonavir with BZF961 was well tolerated and increased BZF961 exposure by up to 60-fold, as well as reduced the overall exposure variability. Conclusions: BZF961 was generally safe and well-tolerated and its exposure was boosted by the co-administration of ritonavir.

Comparative efficacy and safety of second-line antiretroviral therapy for treatment of HIV/AIDS: a systematic review and network meta-analysis

BACKGROUND

Selection of optimal second-line antiretroviral therapy (ART) has important clinical and programmatic implications. To inform the 2016 revision of the WHO ART guidelines, we assessed the comparative effectiveness and safety of available second-line ART regimens for adults and adolescents in whom first-line non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens have failed.

METHODS

In this systematic review and network meta-analysis, we searched for randomised controlled trials and prospective and retrospective cohort studies that evaluated outcomes in treatment-experienced adults living with HIV who switched ART regimen after failure of a WHO-recommended first-line NNRTI-based regimen. We searched Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials for reports published from Jan 1, 1996, to Aug 8, 2016, and searched conference abstracts published from Jan 1, 2014, to Aug 8, 2016. Outcomes of interest were viral suppression, mortality, AIDS-defining illnesses or WHO stage 3-4 disease, discontinuations, discontinuations due to adverse events, and serious adverse events. We assessed comparative efficacy and safety in a network meta-analysis, using Bayesian hierarchical models.

FINDINGS

We identified 12 papers pertaining to eight studies, including 4778 participants. The network was centred on ritonavir-boosted lopinavir plus two nucleoside or nucleotide reverse transcriptase inhibitors. Ritonavir-boosted lopinavir monotherapy was the only regimen inferior to others. With the lower estimate of the 95% credible interval (CrI) not exceeding the predefined threshold of 15%, evidence at 48 weeks supported the non-inferiority of ritonavir-boosted lopinavir plus raltegravir to regimens including ritonavir-boosted protease inhibitor plus two NRTIs with respect to viral suppression (odds ratio 1·09, 95% CrI 0·88-1·35). Estimated efficacy of ritonavir-boosted darunavir (800 mg once daily) was too imprecise to determine non-inferiority. Overall, regimens did not differ significantly with respect to continuations, AIDS-defining illnesses or WHO stage 3-4 disease, or mortality.

INTERPRETATION

With the exception of ritonavir-boosted lopinavir plus raltegravir, the evidence base is unable to provide strong support to alternative second-line options to ritonavir-boosted protease inhibitor plus two NRTIs, and thus more trials are warranted.

FUNDING

WHO.

Efficacy and safety of atazanavir/ritonavir-based antiretroviral therapy for HIV-1 infected subjects: a systematic review and meta-analysis

Atazanavir (ATZ) is a well-tolerated protease inhibitor that can be boosted with ritonavir (r) to treat infection with resistant strains of human immunodeficiency virus 1 (HIV-1). The aim of this meta-analysis was to compare the efficacy, safety, and metabolic effects of ATZ/r regimen versus commonly used antiretroviral drugs such as lopinavir (LPV) and darunavir (DRV) in HIV-1-infected patients. We searched PubMed, Scopus, Embase and Cochrane CENTRAL, using relevant keywords. Data were extracted from eligible randomized trials and pooled as risk ratios (RR) or standardized mean differences (SMD) in a meta-analysis model using RevMan software. Nine randomized controlled trials (RCTs) (3292 patients) were eligible for the final analysis. After 96 weeks of treatment, the pooled effect estimate did not favor either ATZ/r or LPV/r in terms of virological failure rate (RR 1.11, 95% CI [0.74, 1.66]). However, ATZ/r was marginally superior to LPV/r in terms of increasing the proportion of patients with HIV RNA <50 copies/ml (RR 1.09, 95% CI [1.01, 1.17]). The pooled effect estimate did not favor ATZ/r over DRV/r regarding the change in plasma levels of total cholesterol, triglycerides, or high-density lipoprotein at 24, 48, and 96 weeks. Moreover, no significant difference was found between the two regimens (ATZ/r and DRV/r) in terms of change in visceral (SMD -0.06, 95%CI [-0.33, 0.21]) or subcutaneous adipose tissue (SMD 0.12, 95% CI [-0.15, 0.39]). The ATZ/r regimen was generally as effective and well-tolerated as the LPV/r regimen for the treatment of HIV-1 patients. Compared to the DRV/r regimen, ATZ/r has no favorable effect on the plasma lipid profile or adipose tissue distribution.

Prioritizing HIV comparative effectiveness trials based on value of information: generic versus brand-name ART in the US

BACKGROUND

Value of Information (VOI) analysis examines whether to acquire information before making a decision. We introduced VOI to the HIV audience, using the example of generic antiretroviral therapy (ART) in the US.

METHODS AND FINDINGS

We used a mathematical model and probabilistic sensitivity analysis (PSA) to generate probability distributions of survival (in quality-adjusted life years, QALYs) and cost for three potential first-line ART regimens: three-pill generic, two-pill generic, and single-pill branded. These served as input for a comparison of two hypothetical two-arm trials: three-pill generic versus single-pill branded; and two-pill generic versus single-pill branded. We modeled pre-trial uncertainty by defining probability distributions around key inputs, including 24-week HIV-RNA suppression and subsequent ART failure. We assumed that, without a trial, patients received the single-pill branded strategy. Post-trial, we assumed that patients received the most cost-effective strategy. For both trials, we quantified the probability of changing to a generic-based regimen upon trial completion and the expected VOI in terms of improved health outcomes and costs. Assuming a willingness to pay (WTP) threshold of $100 000/QALY, the three-pill trial led to more treatment changes (84%) than the two-pill trial (78%). Estimated VOI was $48 000 (three-pill trial) and $35 700 (two-pill trial) per future patient initiating ART.

CONCLUSIONS

A three-pill trial of generic ART is more likely to lead to post-trial treatment changes and to provide more value than a two-pill trial if policy decisions are based on cost-effectiveness. Value of Information analysis can identify trials likely to confer the greatest impact and value for HIV care.

Efficacy of Once Daily Darunavir/Ritonavir in PI-Naïve, NNRTI-Experienced Patients in the ODIN Trial

Background. An exploratory subanalysis of the ODIN trial was performed to evaluate the efficacy of darunavir/ritonavir (DRV/r) 800/100 mg OD versus 600/100 mg BID in patients who were NNRTI-experienced but PI-naïve. Methods. ODIN was a phase III, 48-week study comparing DRV/r OD versus BID in 590 treatment-experienced patients with no DRV resistance-associated mutations (RAMs) at screening. Patients received DRV/r 800/100 mg OD or DRV/r 600/100 mg BID plus ≥2 NRTIs. Of the 590 patients randomized, 272 (46%) were NNRTI-experienced but PI-naïve. Results. Overall, 272 patients received DRV/r OD (n = 135) or BID (n = 137) plus ≥2 optimised NRTIs. The mean age was 39 years; 35% were female; 27% were Black, 24% Caucasian, 26% Oriental/Asian, and 23% other races; 17% were recruited in South Africa; and 48% had non-B HIV-1 subtypes. Mean baseline plasma HIV-1 RNA load was 4.10 log₁₀⁡ copies/mL; median CD4 cell count was 258 cells/μL. At week 48, 111/135 (82%) of DRV/r OD and 109/137 (80%) of DRV/r BID patients achieved an HIV-1 RNA load <50 copies/mL. No patient developed primary PI RAMs. Conclusion. DRV/r 800/100 mg OD in combination with ≥2 optimised NRTIs led to virological suppression <50 copies/mL in 82% of NNRTI-experienced, PI-naïve patients by week 48.

Efficacy and biological safety of lopinavir/ritonavir based anti-retroviral therapy in HIV-1-infected patients: a meta-analysis of randomized controlled trials

Lopinavir/ritonavir (LPV/r) is the first ritonavir-boosted protease-inhibitor used in second-line anti-retroviral treatment (ART) in resource-limited regions. To evaluate the efficacy and safety outcomes of LPV/r in treatment-naïve and -experienced HIV-infected adults and pregnant women, we performed a meta-analysis of randomized controlled trials. Ten cohorts from 8 articles involving 2,584 ART-naïve patients, 5 cohorts from 4 articles involving 1,124 ART-experienced patients, and 8 cohorts from 7 articles involving 2,191 pregnant women were selected for the meta-analyses. For ART-naïve patients, the virologic response rate (72.3%) of LPV/r combined with tenofovir (TDF) plus lamivudine/emtricitabine (3TC/FTC) arms was significantly greater than that of LPV/r plus non-TDF-FTC arms (65.5%, p = 0.047). For ART-experienced patients, the use of LPV/r revealed a 55.7% probability of virologic success. The incidence of abnormal total cholesterol (6.9%) for ART-experienced patients was significantly lower than that for ART-naïve patients (13.1%, p < 0.001). The use of LPV/r in pregnant women revealed a mother-to-child transmission (MTCT) rate of 1.1%, preterm birth rate of 13.2%, and low birth weight rate of 16.2%. Our meta-analysis indicated that LPV/r was an efficacious regimen for ART-naïve patients and was more tolerable for ART-experienced patients. LPV/r also displayed a significant effect in preventing MTCT.

Pharmacokinetics of Etravirine Combined with Atazanavir/Ritonavir and a Nucleoside Reverse Transcriptase Inhibitor in Antiretroviral Treatment-Experienced, HIV-1-Infected Patients

Objectives. TEACH (NCT00896051) was a randomized, open-label, two-arm Phase II trial to investigate the pharmacokinetic interaction between etravirine and atazanavir/ritonavir and safety and efficacy in treatment-experienced, HIV-1-infected patients. Methods. After a two-week lead-in of two nucleoside reverse transcriptase inhibitors (NRTIs) and atazanavir/ritonavir 300/100 mg, 44 patients received etravirine 200 mg bid with one NRTI, plus atazanavir/ritonavir 300/100 mg or 400/100 mg qd (n = 22 each group) over 48 weeks. Results. At steady-state etravirine with atazanavir/ritonavir 300/100 mg qd or 400/100 mg qd decreased atazanavir C min⁡ by 18% and 9%, respectively, with no change in AUC24 h or C max⁡ versus atazanavir/ritonavir 300/100 mg qd alone (Day -1). Etravirine AUC12 h was 24% higher and 16% lower with atazanavir/ritonavir 300/100 or 400/100 mg qd, respectively, versus historical controls. At Week 48, no significant differences were seen between the atazanavir/ritonavir groups in discontinuations due to adverse events (9.1% each group) and other safety parameters, the proportion of patients with viral load <50 copies/mL (intent-to-treat population, noncompleter = failure) (50.0%, atazanavir/ritonavir 300/100 mg qd versus 45.5%, 400/100 mg qd), and virologic failures (31.8% versus 27.3%, resp.). Conclusions. Etravirine 200 mg bid can be combined with atazanavir/ritonavir 300/100 mg qd and an NRTI in HIV-1-infected, treatment-experienced patients without dose adjustment.

Analysis of Treatment Costs for HIV RNA Reductions and CD4 Increases for Darunavir Versus Other Antiretrovirals in Treatment-Experienced, HIV–Infected Patients

BACKGROUND

For patients with preexisting HIV drug resistance, a wide range of antiretrovirals are used, with differences in efficacy and cost. The additional cost per incremental 25 cell rise in CD4 count, or 0.5 log reduction in HIV RNA, was calculated for 8 antiretrovirals using pivotal clinical trials data.

METHOD

For approved antiretrovirals in HIV therapy--experienced patients, 24-week efficacy (benefit over control in HIV RNA and CD4 count) was extracted from pivotal trials in published reports and compared with the additional treatment cost versus the control arm of each trial (2006 US wholesale acquisition costs). Treatment costs in the POWER trials were calculated directly from the treatment use database.

RESULTS

Data were available from 11 clinical trials in more than 4,000 antiretroviral treatment--experienced patients: Gilead 907 (TDF vs. placebo), TORO1/2 (T-20/OBR vs. OBR), RESIST-1/2 (TPV/r vs. control PI), BMS-045 (ATV/r vs. LPV/r), CONTEXT (fAPV/r vs. LPV/r), CAESAR (3TC vs. placebo), CNA3002 (ABC vs. placebo), and POWER 1/2 (DRV/r vs. control PI). Additional cost per 0.5 log reduction in HIV RNA was $152 for ritonavir-boosted darunavir (DRV/r), $4,453 for lamivudine (3TC), $4,274 for abacavir (ABC), $4,641 for tenofovir (TDF), and $13,217 for enfuvirtide (T-20). Cost per 25 cell rise in CD4 ranged from $132 for darunavir/r to $16,464 for T-20.

CONCLUSION

There is a wide range of costs associated with efficacy improvements across the classes of antiretrovirals used for antiretroviral treatment--experienced patients. This analysis does not account for differences in toxicity, use of concomitant medications, or long-term adherence, which could also influence value assessments.

Cost effectiveness of darunavir/ritonavir combination antiretroviral therapy for treatment-naive adults with HIV-1 infection in Canada

OBJECTIVE

The AntiRetroviral Therapy with TMC114 ExaMined In naive Subjects (ARTEMIS) clinical trial examined the efficacy and safety of two ritonavir-boosted protease inhibitors (PI/r), darunavir/r 800/100 mg once daily (QD) and lopinavir/r 800/200 mg daily, both used in combination with tenofovir disoproxil fumarate/emtricitabine. This study aimed to assess the cost effectiveness of the darunavir/r regimen compared with the lopinavir/r regimen in treatment-naive adults with HIV-1 infection in Canada.

METHODS

A Markov model with a 3-month cycle time and six CD4 cell-count-based health states (>500, 351-500, 201-500, 101-200, 51-100, and 0-50 cells/mm(3)) followed a cohort of treatment-naive adults with HIV-1 infection through initial darunavir/r or lopinavir/r combination therapy and a common set of subsequent regimens over the course of their remaining lifetimes. Population characteristics and transition probabilities were estimated from the ARTEMIS clinical trial and other trials. Costs (in 2014 Canadian dollars), utilities, and mortality were estimated from Canadian sources and published literature. Costs and health outcomes were discounted at 5% per year. One-way and probabilistic sensitivity analyses were performed, including a simple indirect comparison of the darunavir/r initial regimen with an atazanavir/r-based regimen.

RESULTS

In the base-case lifetime analysis, individuals receiving initial therapy with the darunavir/r regimen experienced 0.25 more quality-adjusted life-years (QALYs) with lower antiretroviral drug costs (-$14,246) and total costs (-$18,402) than individuals receiving the lopinavir/r regimen, indicating that darunavir/r dominated lopinavir/r. In an indirect comparison with an atazanavir/r-based regimen, the darunavir/r regimen remained the dominant choice, but with lower cost savings (-$2,303) and QALY gains (0.02). Results were robust to a wide range of other changes in input parameter values, population characteristics, and modeling assumptions. The probabilistic sensitivity analysis demonstrated that the darunavir/r regimen was cost effective compared with the lopinavir/r regimen in over 86% of simulations for willingness-to-pay thresholds between $0 and $100,000 per QALY gained.

CONCLUSIONS

Darunavir/r 800/100 mg QD may be a cost-effective PI/r component of initial antiretroviral therapy for treatment-naive adults with HIV-1 infection in Canada.

HIV protease inhibitors in gut barrier dysfunction and liver injury

The development of HIV protease inhibitors (HIV PIs) has been one of the most significant advances of the past two decades in controlling HIV infection. HIV PIs have been used successfully in highly active anti-retroviral therapy (HAART) for HIV infection, which is currently the most effective treatment available. Incorporation of HIV PIs in HAART causes profound and sustained suppression of viral replication, significantly reduces the morbidity and mortality of HIV infection, and prolongs the lifespan of HIV patients. However, in the era of HAART, drug-induced gastrointestinal (GI) side effects and hepatotoxicity have emerged as important potential complications of HIV therapy, particularly those regimens containing HIV PIs. In this mini-review, we highlight the current understanding of the mechanisms of HIV PI-associated GI and liver injury.

Nucleoside-sparing antiretroviral regimens

Nucleoside reverse transcriptase inhibitors (NRTIs) were the first drugs approved for use as antiretroviral therapy in patients infected with HIV. Despite the introduction of other classes of antiretroviral drugs, they remain an important component of combination regimens as recommended by many treatment guidelines. They also continue to be used in prevention of disease from mother to child, postexposure prophylaxis, and more recently for preexposure prophylaxis. Unfortunately, the toxicities associated with this class of drugs can limit their use. Although NRTI-sparing regimens are not currently recommended for first-line therapy there is an increasing amount of data supporting their use in both treatment-naive and in treatment-experienced patients.

A systematic review of the use of atazanavir in women infected with HIV-1

BACKGROUND

Despite increasing numbers of women with HIV worldwide, females are under-represented in clinical trials of antiretrovirals and literature addressing gender differences in clinical outcomes, treatment discontinuation, adverse events and adherence are limited. Most recommendations specific to women in current guidelines relate to pregnant women or women wishing to become pregnant. The purpose of this systematic review is to provide clinicians with an overview of available literature regarding the use of ritonavir-boosted atazanavir (ATV/r) in women.

METHODS

The online databases PubMed and EMBASE, HIV-related conference abstracts and reference lists of relevant articles were searched according to predefined terms and limited to items published from 1 October 2007 to 1 October 2012. Updates to conference presentations were checked for substantive journal publication up to 28 November 2013.

RESULTS

Of the 294 initial citations retrieved, manual selection identified 19 relevant publications describing gender-based analyses of ATV/r. Publications describing gender-based differences in efficacy, safety, tolerability, pharmacokinetics, drug-drug interactions and adherence are critically evaluated.

CONCLUSIONS

As part of a combination antiretroviral therapy regimen, ATV/r appears to be a safe, effective and durable option for treatment-naive and early treatment-experienced patients with HIV-1 infection, including non-pregnant and pregnant women.

The cost-effectiveness of improved hepatitis C virus therapies in HIV/hepatitis C virus coinfected patients

OBJECTIVES

To evaluate the effectiveness and cost-effectiveness of strategies to treat hepatitis C virus (HCV) in HIV/HCV coinfected patients in the United States.

PARTICIPANTS

Simulated cohort of HIV/HCV genotype 1 coinfected, noncirrhotic, HCV treatment-naive individuals enrolled in US HIV guideline-concordant care.

DESIGN/INTERVENTIONS

Monte Carlo simulation comparing five strategies: no treatment; dual therapy with pegylated-interferon (PEG) and ribavirin (RBV); 'PEG/RBV trial' in which all patients initiate dual therapy and switch to triple therapy upon failure; 'IL28B triage' in which patients initiate either dual therapy or triple therapy based on their IL28B allele type; and PEG/RBV and telaprevir (TPV) triple therapy. Sensitivity analyses varied efficacies and costs and included a scenario with interferon (IFN)-free therapy.

MAIN MEASURES

Sustained virologic response (SVR), life expectancy, discounted quality-adjusted life expectancy (QALE), lifetime medical costs, and incremental cost-effectiveness ratios (ICERs) in $/quality-adjusted life years (QALY) gained.

RESULTS

'PEG/RBV trial,' 'IL28B triage,' and 'triple therapy' each provided 72% SVR and extended QALE compared with 'dual therapy' by 1.12, 1.14, and 1.15 QALY, respectively. The ICER of 'PEG/RBV trial' compared with 'dual therapy' was $37 500/QALY. 'IL28B triage' and 'triple therapy' provided little benefit compared with 'PEG/RBV trial,' and both had ICERs exceeding $300 000/QALY. In sensitivity analyses, IFN-free treatment attaining 90% SVR had an ICER less than $100 000/QALY compared with 'PEG/RBV trial' when its cost was $109 000 or less (125% of the cost of PEG/RBV/TVR).

CONCLUSION

HCV protease inhibitors are most efficiently used in HIV/HCV coinfection after a trial of PEG/RBV, sparing protease inhibitors for those who attain rapid virologic response and SVR. The cost-effectiveness of IFN-free regimens for HIV/HCV coinfection will depend on the cost of these therapies.

Mobile HIV screening in Cape Town, South Africa: clinical impact, cost and cost-effectiveness

BACKGROUND

Mobile HIV screening may facilitate early HIV diagnosis. Our objective was to examine the cost-effectiveness of adding a mobile screening unit to current medical facility-based HIV testing in Cape Town, South Africa.

METHODS AND FINDINGS

We used the Cost Effectiveness of Preventing AIDS Complications International (CEPAC-I) computer simulation model to evaluate two HIV screening strategies in Cape Town: 1) medical facility-based testing (the current standard of care) and 2) addition of a mobile HIV-testing unit intervention in the same community. Baseline input parameters were derived from a Cape Town-based mobile unit that tested 18,870 individuals over 2 years: prevalence of previously undiagnosed HIV (6.6%), mean CD4 count at diagnosis (males 423/µL, females 516/µL), CD4 count-dependent linkage to care rates (males 31%-58%, females 49%-58%), mobile unit intervention cost (includes acquisition, operation and HIV test costs, $29.30 per negative result and $31.30 per positive result). We conducted extensive sensitivity analyses to evaluate input uncertainty. Model outcomes included site of HIV diagnosis, life expectancy, medical costs, and the incremental cost-effectiveness ratio (ICER) of the intervention compared to medical facility-based testing. We considered the intervention to be "very cost-effective" when the ICER was less than South Africa's annual per capita Gross Domestic Product (GDP) ($8,200 in 2012). We projected that, with medical facility-based testing, the discounted (undiscounted) HIV-infected population life expectancy was 132.2 (197.7) months; this increased to 140.7 (211.7) months with the addition of the mobile unit. The ICER for the mobile unit was $2,400/year of life saved (YLS). Results were most sensitive to the previously undiagnosed HIV prevalence, linkage to care rates, and frequency of HIV testing at medical facilities.

CONCLUSION

The addition of mobile HIV screening to current testing programs can improve survival and be very cost-effective in South Africa and other resource-limited settings, and should be a priority.

Tenofovir disoproxil fumarate–emtricitabine coformulation for once-daily dual NRTI backbone

Truvada is the coformulation of tenofovir disoproxil fumarate (TDF; 300 mg) and emtricitabine (FTC; 200 mg) in a single tablet, providing the nucleotide backbone for once-daily dosing, as a component of highly active antiretroviral therapy (HAART). TDF (the bioavailable prodrug of tenofovir) is hydrolyzed to tenofovir intracellularly and phosphorylated to the active metabolite, tenofovir diphosphate. Tenofovir is a nucleotide analog of deoxyadenosine monophosphate, with activity against HIV-1, -2 and hepatitis B virus. FTC, the fluorinated derivative of lamivudine, is an analog of deoxycitidine, active against HIV-1, -2 and hepatitis B virus. Their long half-lives in plasma and in peripheral blood mononuclear cells allow once-daily dosing. Both are eliminated renally. Resistance mutation K65R is selected for by tenofovir and confers a two- to fourfold reduced susceptibility to this drug. The incidence of K65R is low (3%) and has not been observed in clinical trials with the concomitant use of tenofovir and FTC. FTC selects for M184V mutation less frequently than lamivudine. Tenofovir drug interactions include increased exposure to didanosine and inferior immune recovery that preclude their concomitant use. Boosted protease inhibitors increase exposure to tenofovir without dose adjustment required. FTC has no significant drug interactions. They are not metabolized by cytochrome P450, which confers little potential for interactions with drugs metabolized by these enzymes. As tenofovir and FTC are renally eliminated, drugs eliminated by tubular secretion must be avoided. Both antiretrovirals, as individual agents and in coadministration have evidenced antiviral potency in clinical trials. Pivotal study 934 evidenced superior efficacy of the combination TDF/FTC/efavirenz (EFV) versus zidovudine/FTC/EFV. The toxicity profile of tenofovir and FTC has been extensively studied. Lipid profile is more favorable with tenofovir than thymidine analog. Tenofovir requires surveillance of glomerular filtration rate and dosing interval adjustment when creatinine clearance is less than 50 ml/min and avoidance less than 30 ml/min. Fat loss is less likely with tenofovir than with thymidine analog. Clinical trials have assessed the performance of the coformulation of TDF and FTC.

Routine HIV screening in Portugal: clinical impact and cost-effectiveness

OBJECTIVE

To compare the clinical outcomes and cost-effectiveness of routine HIV screening in Portugal to the current practice of targeted and on-demand screening.

DESIGN

We used Portuguese national clinical and economic data to conduct a model-based assessment.

METHODS

We compared current HIV detection practices to strategies of increasingly frequent routine HIV screening in Portuguese adults aged 18-69. We considered several subpopulations and geographic regions with varying levels of undetected HIV prevalence and incidence. Baseline inputs for the national case included undiagnosed HIV prevalence 0.16%, annual incidence 0.03%, mean population age 43 years, mean CD4 count at care initiation 292 cells/μL, 63% HIV test acceptance, 78% linkage to care, and HIV rapid test cost €6 under the proposed routine screening program. Outcomes included quality-adjusted survival, secondary HIV transmission, cost, and incremental cost-effectiveness.

RESULTS

One-time national HIV screening increased HIV-infected survival from 164.09 quality-adjusted life months (QALMs) to 166.83 QALMs compared to current practice and had an incremental cost-effectiveness ratio (ICER) of €28,000 per quality-adjusted life year (QALY). Screening more frequently in higher-risk groups was cost-effective: for example screening annually in men who have sex with men or screening every three years in regions with higher incidence and prevalence produced ICERs of €21,000/QALY and €34,000/QALY, respectively.

CONCLUSIONS

One-time HIV screening in the Portuguese national population will increase survival and is cost-effective by international standards. More frequent screening in higher-risk regions and subpopulations is also justified. Given Portugal's challenging economic priorities, we recommend prioritizing screening in higher-risk populations and geographic settings.

The survival benefits of antiretroviral therapy in South Africa

BACKGROUND

We sought to quantify the survival benefits attributable to antiretroviral therapy (ART) in South Africa since 2004.

METHODS

We used the Cost-Effectiveness of Preventing AIDS Complications-International model (CEPAC) to simulate 8 cohorts of human immunodeficiency virus (HIV)-infected patients initiating ART each year during 2004-2011. Model inputs included cohort-specific mean CD4(+) T-cell count at ART initiation (112-178 cells/µL), 24-week ART suppressive efficacy (78%), second-line ART availability (2.4% of ART recipients), and cohort-specific 36-month retention rate (55%-71%). CEPAC simulated survival twice for each cohort, once with and once without ART. The sum of the products of per capita survival differences and the total numbers of persons initiating ART for each cohort yielded the total survival benefits.

RESULTS

Lifetime per capita survival benefits ranged from 9.3 to 10.2 life-years across the 8 cohorts. Total estimated population lifetime survival benefit for all persons starting ART during 2004-2011 was 21.7 million life-years, of which 2.8 million life-years (12.7%) had been realized by December 2012. By 2030, benefits reached 17.9 million life-years under current policies, 21.7 million life-years with universal second-line ART, 23.3 million life-years with increased linkage to care of eligible untreated patients, and 28.0 million life-years with both linkage to care and universal second-line ART.

CONCLUSIONS

We found dramatic past and potential future survival benefits attributable to ART, justifying international support of ART rollout in South Africa.

Contribution of Gag and protease to variation in susceptibility to protease inhibitors between different strains of subtype B human immunodeficiency virus type 1

Recent reports have shown that human immunodeficiency virus type 1 (HIV-1) Gag can directly affect susceptibility to protease inhibitors (PIs) in the absence of known resistance mutations in protease. Inclusion of co-evolved Gag alongside protease in phenotypic drug susceptibility assays can alter PI susceptibility in comparison with protease with a WT Gag. Using a single-replication-cycle assay encompassing full-length Gag together with protease we demonstrated significant variation in PI susceptibility between a number of PI-naïve subtype B viruses. Six publicly available subtype B molecular clones, namely HXB2, NL4-3, SF2, YU2, JRFL and 89.6, displayed up to nine-fold reduced PI susceptibility in comparison with the assay reference strain. For two molecular clones, YU2 and JRFL, Gag contributed solely to the observed reduction in susceptibility, with the N-terminal region of Gag contributing significantly. Gag and protease from treatment-naïve, patient-derived viruses also demonstrated significant variation in susceptibility, with up to a 17-fold reduction to atazanavir in comparison with the assay reference strain. In contrast to the molecular clones, protease was the main determinant of the reduced susceptibility. Common polymorphisms in protease, including I13V, L63P and A71T, were shown to contribute to this reduction in PI susceptibility, in the absence of major resistance mutations. This study demonstrated significant variation in PI susceptibility of treatment-naïve patient viruses, and provided further evidence of the independent role of Gag, the protease substrate and in particular the N-terminus of Gag in PI susceptibility. It also highlighted the importance of considering co-evolved Gag and protease when assessing PI susceptibility.

Crofelemer for the treatment of chronic diarrhea in patients living with HIV/AIDS

Diarrhea is a common comorbidity present in patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) who are treated with highly active antiretroviral therapy. With a multifactorial etiology, this diarrhea often becomes difficult to manage. In addition, some antiretrovirals are associated with chronic diarrhea, which potentially creates an adherence barrier to antiretrovirals and may ultimately affect treatment outcomes and future therapeutic options for HIV. A predominant type of diarrhea that develops in HIV patients has secretory characteristics, including increased secretion of chloride ions and water into the intestinal lumen. One proposed mechanism that may lead to this type of secretory diarrhea is explained by the activation of the cystic fibrosis transmembrane conductance regulator and calcium-activated chloride channels. Crofelemer is a novel antidiarrheal agent that works by inhibiting both of these channels. The efficacy and safety of crofelemer has been evaluated in clinical trials for various types of secretory diarrhea, including cholera-related and acute infectious diarrhea. More recently, crofelemer was approved by the US Food and Drug Administration for the symptomatic relief of noninfectious diarrhea in adult patients with HIV/AIDS on antiretroviral therapy. Results from the ADVENT trial showed that crofelemer reduced symptoms of secretory diarrhea in HIV/AIDS patients. Because crofelemer is not systemically absorbed, this agent is well tolerated by patients, and in clinical trials it has been associated with minimal adverse events. Crofelemer has a unique mechanism of action, which may offer a more reliable treatment option for HIV patients who experience chronic secretory diarrhea from antiretroviral therapy.

Atazanavir and other determinants of hyperbilirubinemia in a cohort of 1150 HIV-positive patients: results from 9 years of follow-up

Hyperbilirubinemia is common among patients exposed to atazanavir (ATV), but its long-term significance is not well documented. The objective was to analyze hyperbilirubinemia (incidence, regression, determinants, and outcome) among 1150 HIV-positive patients followed-up in a prospective cohort between 2003 and 2012. Cumulative incidence of hyperbilirubinemia grades 3-4 and its probability of regression were estimated using Kaplan-Meier method. Cox proportional hazards model was used to study the determinants. Generalized estimating equation (GEE) regression was used to evaluate the association between hyperbilirubinemia grades 3-4 and adverse health outcome. Eight years cumulative incidence of hyperbilirubinemia was 83.6% (95% CI:79.0-87.7) and 6.6% (95% CI:4.7-9.2) among ATV users and non-users, respectively. This clinical outcome fluctuated considerably, as most patients exposed to ATV (91%) regressed, transiently, to lower grade at some point during follow-up. Determinants were atazanavir (HR=147.90, 95% CI: 33.64-604.18), ritonavir (HR=5.18, 95% CI:2.33-11.48), zidovudine (HR=2.62, 95% CI:1.07-6.46), and age (HR=1.04 95% CI:1.01-1.08). Alcohol consumption and others non-antiretroviral medications including hepatotoxic and recreational drugs were not available for analyses. Incidence of hyperbilirubinemia was very high among ATV users and, although regression to lower grade was frequent in the clinical follow-up of these patients, this was usually transient as the mean level of bilirubin stayed at a relatively high level. Importantly, long-term hyperbilirubinemia was not associated with adverse health outcome.

Provider compliance with guidelines for management of cardiovascular risk in HIV-infected patients

Introduction

Compliance with National Cholesterol Education Program Adult Treatment Panel III (NCEP) guidelines has been shown to significantly reduce incident cardiovascular events. We investigated physicians’ compliance with NCEP guidelines to reduce cardiovascular disease (CVD) risk in a population infected with HIV.

Methods

We analyzed HIV Outpatient Study (HOPS) data, following eligible patients from January 1, 2002, or first HOPS visit thereafter to calculate 10-year cardiovascular risk (10yCVR), until September 30, 2009, death, or last office visit. We categorized participants into four 10yCVR strata, according to guidelines determined by NCEP, the Infectious Disease Society of America, and the Adult AIDS Clinical Trials Group. We calculated percentages of patients treated for dyslipidemia and hypertension, calculated percentages of patients who achieved recommended goals, and categorized them by 10yCVR stratum.

Results

Of 2,005 patients analyzed, 33.7% had fewer than 2 CVD risk factors. For patients who had 2 or more risk factors, 10yCVR was less than 10% for 28.2%, 10% to 20% for 18.2%, and higher than 20% for 20.0% of patients. Of patients eligible for treatment, 81% to 87% were treated for elevated low-density lipoprotein cholesterol/non–high-density lipoprotein cholesterol (LDL-C/non–HDL-C), 2% to 11% were treated for low HDL-C, 56% to 91% were treated for high triglycerides, and 46% to 69% were treated for hypertension. Patients in higher 10yCVR categories were less likely to meet treatment goals than patients in lower 10yCVR categories.

Conclusion

At least one-fifth of contemporary HOPS patients have a 10yCVR higher than 20%, yet a large percentage of at-risk patients who were eligible for pharmacologic treatment did not receive recommended interventions and did not reach recommended treatment goals. Opportunities exist for CVD prevention in the HIV-infected population.

The cost-effectiveness of rapid HIV testing in substance abuse treatment: results of a randomized trial

BACKGROUND

The President's National HIV/AIDS Strategy calls for coupling HIV screening and prevention services with substance abuse treatment programs. Fewer than half of US community-based substance abuse treatment programs make HIV testing available on-site or through referral.

METHODS

We measured the cost-effectiveness of three HIV testing strategies evaluated in a randomized trial conducted in 12 community-based substance abuse treatment programs in 2009: off-site testing referral, on-site rapid testing with information only, on-site rapid testing with risk-reduction counseling. Data from the trial included patient demographics, prior testing history, test acceptance and receipt of results, undiagnosed HIV prevalence (0.4%) and program costs. The Cost-Effectiveness of Preventing AIDS Complications (CEPAC) computer simulation model was used to project life expectancy, lifetime costs, and quality-adjusted life years (QALYs) for HIV-infected individuals. Incremental cost-effectiveness ratios (2009 US $/QALY) were calculated after adding costs of testing HIV-uninfected individuals; costs and QALYs were discounted at 3% annually.

RESULTS

Referral for off-site testing is less efficient (dominated) compared to offering on-site testing with information only. The cost-effectiveness ratio for on-site testing with information is $60,300/QALY in the base case, or $76,300/QALY with 0.1% undiagnosed HIV prevalence. HIV risk-reduction counseling costs $36 per person more without additional benefit.

CONCLUSIONS

A strategy of on-site rapid HIV testing offer with information only in substance abuse treatment programs increases life expectancy at a cost-effectiveness ratio <$100,000/QALY. Policymakers and substance abuse treatment leaders should seek funding to implement on-site rapid HIV testing in substance abuse treatment programs for those not recently tested.

Economic savings versus health losses: the cost-effectiveness of generic antiretroviral therapy in the United States

BACKGROUND

U.S. HIV treatment guidelines recommend branded once-daily, 1-pill efavirenz-emtricitabine-tenofovir as first-line antiretroviral therapy (ART). With the anticipated approval of generic efavirenz in the United States, a once-daily, 3-pill alternative (generic efavirenz, generic lamivudine, and tenofovir) will decrease cost but may reduce adherence and virologic suppression.

OBJECTIVE

To assess the clinical effect, costs, and cost-effectiveness of a 3-pill, generic-based regimen compared with a branded, coformulated regimen and to project the potential national savings in the first year of a switch to generic-based ART.

DESIGN

Mathematical simulation of HIV disease.

SETTING

United States.

PATIENTS

HIV-infected persons.

INTERVENTION

No ART (for comparison); 3-pill, generic-based ART; and branded ART.

MEASUREMENTS

Quality-adjusted life expectancy, costs, and incremental cost-effectiveness ratios (ICERs) in dollars per quality-adjusted life-year (QALY).

RESULTS

Compared with no ART, generic-based ART has an ICER of $21,100/QALY. Compared with generic-based ART, branded ART increases lifetime costs by $42,500 and per-person survival gains by 0.37 QALYs for an ICER of $114,800/QALY. Estimated first-year savings, if all eligible U.S. patients start or switch to generic-based ART, are $920 million. Most plausible assumptions about generic-based ART efficacy and costs lead to branded ART ICERs greater than $100,000/QALY.

LIMITATION

The efficacy and price reduction associated with generic drugs are unknown, and estimates are intended to be conservative.

CONCLUSION

Compared with a slightly less effective generic-based regimen, the cost-effectiveness of first-line branded ART exceeds $100,000/QALY. Generic-based ART in the United States could yield substantial budgetary savings to HIV programs.

PRIMARY FUNDING SOURCE

National Institute of Allergy and Infectious Diseases.

Cost-effectiveness analysis of UGT1A1 genetic testing to inform antiretroviral prescribing in HIV disease

BACKGROUND

Homozygosity for UGT1A1*28/*28 has been reported to be associated with atazanavir-associated hyperbilirubinaemia and premature atazanavir discontinuation. We assessed the potential cost-effectiveness of UGT1A1 testing to inform the choice of an initial protease-inhibitor-containing regimen in antiretroviral therapy (ART)-naive individuals.

METHODS

We used the Cost-Effectiveness of Preventing AIDS Complications computer simulation model to project quality-adjusted life years (QALYs) and lifetime costs (2009 USD) for atazanavir-based ART with or without UGT1A1 testing, using darunavir rather than atazanavir when indicated. We assumed the UGT1A1-associated atazanavir discontinuation rate reported in the Swiss HIV Cohort Study (a *28/*28 frequency of 14.9%), equal efficacy and cost of atazanavir and darunavir and a genetic assay cost of $107. These parameters, as well as the effect of hyperbilirubinaemia on quality of life and loss to follow up, were varied in sensitivity analyses. Costs and QALYs were discounted at 3% annually.

RESULTS

Initiating atazanavir-based ART at CD4(+) T-cell counts <500 cells/μl without UGT1A1 testing had an average discounted life expectancy of 16.02 QALYs and $475,800 discounted lifetime cost. Testing for UGT1A1 increased QALYs by 0.49 per 10,000 patients tested and was not cost-effective (>$100,000/QALY). Testing for UGT1A1 was cost-effective (<$100,000/QALY) if assay cost decreased to $10, or if avoiding hyperbilirubinaemia by UGT1A1 testing reduced loss to follow-up by 5%. If atazanavir and darunavir differed in cost or efficacy, testing for UGT1A1 was not cost-effective under any scenario.

CONCLUSIONS

Testing for UGT1A1 may be cost-effective if assay cost is low and if testing improves retention in care, but only if the comparator ART regimens have the same drug cost and efficacy.

Differences in implementation of HIV/AIDS clinical research in developed versus developing world: an evidence-based review on protease inhibitor use among women and minorities

The aim of this revision is to evaluate ethnicity and gender rate of enrolment in registrative clinical trials of the protease inhibitors (Pis) from 1996 to 2009. Company-sponsored, phase II or III registrative clinical trials of PIs were evaluated. Forty-nine clinical trials were included. Clinical trials were conducted in centres in North America ( n = 39), Central-South America ( n = 22), Europe ( n = 22), Africa ( n = 8), Asia ( n = 5), Australia ( n = 10). Overall mean age was 39.6 years; median proportion of women was 16.3%. The most represented ethnic group was Caucasian. A test for trend over time (1996-2009) shows a significant increase in the proportion of women included ( P = 0.012), and a decrease in the proportion of Caucasians included, reaching borderline significance ( P = 0.061). An inverse correlation was observed between the proportion of Caucasians and that of women enrolled in each study ( r = 0.65, P < 0.0001). Women were less likely to be included in double-blind studies (11.2% versus 17%, P = 0.019). Clinical trials for treatment-naive subjects were more likely to enrol ethnicities other than Caucasian compared with Caucasian (44.7% versus 27.1 %, respectively, P = 0.04). Rates of enrolment of minorities in registrative clinical trials for PIs show a positive trend since 1996, mirroring the growing number of people of different ethnic groups accessing ART.

The clinical and economic impact of genotype testing at first-line antiretroviral therapy failure for HIV-infected patients in South Africa

BACKGROUND

In resource-limited settings, genotype testing at virologic failure on first-line antiretroviral therapy (ART) may identify patients with wild-type (WT) virus. After adherence counseling, these patients may safely and effectively continue first-line ART, thereby delaying more expensive second-line ART.

METHODS

We used the Cost-Effectiveness of Preventing AIDS Complications International model of human immunodeficiency virus (HIV) disease to simulate a South African cohort of HIV-infected adults at first-line ART failure. Two strategies were examined: no genotype vs genotype, assuming availability of protease inhibitor-based second-line ART. Model inputs at first-line ART failure were mean age 38 years, mean CD4 173/µL, and WT virus prevalence 20%; genotype cost was $300 per test and delay to results, 3 months. Outcomes included life expectancy, per-person costs (2010 US dollars), and incremental cost-effectiveness ratios (dollars per years of life saved [YLS]).

RESULTS

No genotype had a projected life expectancy of 106.1 months, which with genotype increased to 108.3 months. Per-person discounted lifetime costs were $16 360 and $16 540, respectively. Compared to no genotype, genotype was very cost-effective, by international guidance, at $900/YLS. The cost-effectiveness of genotype was sensitive to prevalence of WT virus (very cost-effective when prevalence ≥ 12%), CD4 at first-line ART failure, and ART efficacy. Genotype-associated delays in care ≥ 5 months decreased survival and made no genotype the preferred strategy. When the test cost was <$100, genotype became cost-saving.

CONCLUSIONS

Genotype resistance testing at first-line ART failure is very cost-effective in South Africa. The cost-effectiveness of this strategy will depend on prevalence of WT virus and timely response to genotype results.

HIV antiretroviral medications and hepatotoxicity

PURPOSE OF REVIEW

This review considers the differential diagnosis, pathophysiology and risk of hepatotoxicity of specific antiretroviral medications.

RECENT FINDINGS

Currently prescribed antiretroviral medications are associated with an incidence of grade 3/4 liver enzyme elevation of less than 5%. Clinically apparent hepatotoxicity rates are much lower. The risk of adverse events with combination HIV and hepatitis C virus treatments is low, assuming that several nucleosides including didanosine and stavudine are avoided.

SUMMARY

Irrespective of the HIV antiretroviral regimen prescribed, careful observation of liver function and enzymes is advised, especially in those with comorbid liver disease. The majority of patients do not experience treatment-limiting liver toxicities, achieve virological suppression, and realize immunological restoration.

A nucleoside- and ritonavir-sparing regimen containing atazanavir plus raltegravir in antiretroviral treatment-naïve HIV-infected patients: SPARTAN study results

BACKGROUND

Nucleoside and ritonavir (RTV) toxicities have led to increased interest in nucleoside reverse transcriptase inhibitors (NRTIs) and RTV-sparing antiretroviral regimens. SPARTAN was a multicenter, randomized, open-label, noncomparative pilot study evaluating the efficacy, safety, and resistance profile of an investigational NRTI- and RTV-sparing regimen (experimental atazanavir [ATV] dose 300 mg bid + raltegravir [RAL] 400 mg bid [ATV+RAL]). The reference regimen consisted of ATV 300 mg/RTV 100 mg qd + tenofovir (TDF) 300 mg/emtricitabine (FTC) 200 mg qd (ATV/r+TDF/FTC).

METHODS

Treatment-naïve HIV-infected patients with HIV-RNA ≥5,000 copies/mL were randomized 2:1 to receive twice-daily ATV+RAL (n=63) or once-daily ATV/r+TDF/FTC (n=31). Efficacy at 24 weeks was determined by confirmed virologic response (CVR; HIV-RNA <50 copies/mL) with noncom-pleters counted as failures based on all treated subjects.

RESULTS

The proportion of patients with CVR HIV RNA <50 copies/mL at week 24 was 74.6% (47/63) in the ATV+RAL arm and 63.3% (19/30) in the ATV/r+TDF/FTC arm. Systemic exposure to ATV in the ATV+RAL regimen was higher than historically observed with ATV/r+TDF/ FTC. Incidence of Grade 4 hyperbilirubinemia was higher on ATV+RAL (20.6%; 13/63) than on ATV/r+TDF/FTC (0%). The criteria for resistance testing (virologic failure [VF]: HIV-RNA ≥400 copies/mL) was met in 6/63 patients on ATV+RAL, and 1/30 on ATV/r+TDF/FTC; 4 VFs on ATV+RAL developed RAL resistance.

CONCLUSIONS

ATV+RAL, an experimental NRTI- and RTV-sparing regimen, achieved virologic suppression rates comparable to current standards of care for treatment-naïve patients. The overall profile did not appear optimal for further clinical development given its development of resistance to RAL and higher rates of hyperbilirubinemia with twice-daily ATV compared with ATV/RTV.

Etiology and pharmacologic management of noninfectious diarrhea in HIV-infected individuals in the highly active antiretroviral therapy era

Diarrhea remains a common problem for patients with human immunodeficiency virus (HIV) infection despite highly active antiretroviral therapies (HAART) and can negatively affect patient quality of life and lead to discontinuation or switching of HAART regimens. In the era of HAART, diarrhea from opportunistic infections is uncommon, and HIV-associated diarrhea often has noninfectious causes, including HAART-related adverse events and HIV enteropathy. Diarrhea associated with HAART is typically caused by protease inhibitors (eg, ritonavir), which may damage the intestinal epithelial barrier (leaky-flux diarrhea) and/or alter chloride ion secretion (secretory diarrhea). HIV enteropathy may result from direct effects of HIV on gastrointestinal tract cells and on the gastrointestinal immune system and gut-associated lymphoid tissue, which may be active sites of HIV infection and ongoing inflammation and mucosal damage. New therapies targeting the pathogenic mechanisms of noninfectious diarrheas are needed.

Genotype assays and third-line ART in resource-limited settings: a simulation and cost-effectiveness analysis of a planned clinical trial

OBJECTIVES

To project the clinical and economic outcomes of a genotype assay for selection of third-line antiretroviral therapy (ART) in resource-limited settings, as per the planned international A5288 trial (MULTI-OCTAVE).

METHODS

We used the Cost-effectiveness of Preventing AIDS Complications (CEPAC)-International Model to compare three strategies for patients who have failed second-line ART in South Africa: sustained second-line: no genotype assay, all patients remain on second-line ART; A5288: genotype to determine the resistance profile and assign an appropriate regimen; or population-based third-line: no genotype, all patients switch to a potent third-line regimen. Model inputs are from published data in South Africa. Resistance profiles, ART regimens, and efficacy data were those used for trial planning.

RESULTS

Projected life expectancy for sustained second-line, A5288, and population-based third-line are 61.1, 103.8, and 104.2 months. Compared to sustained second-line ($12 ,460), per person lifetime costs increase for the A5288 ($39, 250) and population-based ($44, 120) strategies. The incremental cost-effectiveness ratio of A5288, compared to sustained second-line, is $7500/year of life saved (YLS), and for population-based third-line, compared to A5288, is $154 ,500/YLS. In the A5288 strategy, very late presentation to care, coupled with lengthy delays to obtain the genotype, dramatically reduces 5-year survival, making the population-based third-line strategy more attractive.

CONCLUSIONS

We project that, whereas the public health approach to third-line therapy is unaffordable, genotype assays and third-line ART in resource-limited settings will increase survival and be cost-effective compared to the population-based approach, supporting the value of an efficacy study.

Clinical significance of hyperbilirubinemia among HIV-1-infected patients treated with atazanavir/ritonavir through 96 weeks in the CASTLE study

CASTLE was a randomized 96-week study that demonstrated that atazanavir/ritonavir (ATV/r) was noninferior to lopinavir/ritonavir (LPV/r) in treatment-naïve HIV-infected patients. Analyses were carried out among patients who received ATV/r in the CASTLE study to better understand the clinical significance of unconjugated hyperbilirubinemia associated with administration of boosted ATV. Hyperbilirubinemia was defined as total bilirubin (conjugated and unconjugated) elevation greater than 2.5 times the upper limit of normal (grade 3-4). Patients in the ATV/r arm were assessed based on the presence or absence of hyperbilirubinemia through week 96. Analyses included number of confirmed virologic responders (CVR; HIV RNA<50 copies per milliliter), impact of hyperbilirubinemia on symptoms, elevations in liver enzymes, patient quality of life, and medication adherence. Through 96 weeks in the CASTLE study, 44% of patients who received ATV/r had hyperbilirubinemia at any time point, and between 12.5% and 21.6% had hyperbilirubinemia at any single study visit. At 96 weeks, 74% of patients overall and 84% and 69% of patients with and without hyperbilirubinemia, respectively, achieved CVR. Symptoms of jaundice or scleral icterus occurred in 5% of patients overall and in 11% with hyperbilirubinemia and 0% without hyperbilirubinemia. Four percent of patients with and 3% of patients without hyperbilirubinemia had grade 3-4 elevations in liver transaminases. Less than 1% of patients discontinued treatment due to hyperbilirubinemia. There were no differences in quality of life or adherence between patients with or without hyperbilirubinemia. In the CASTLE study, hyperbilirubinemia observed in the ATV/r group did not negatively impact clinical outcomes in HIV-infected patients.

Diarrhea associated with lopinavir/ritonavir-based therapy: results of a meta-analysis of 1469 HIV-1-infected participants

BACKGROUND

Antiretroviral therapy is associated with adverse events (AEs). The most frequently reported AE associated with lopinavir/ritonavir (LPV/r) containing regimens is diarrhea. The objective of this meta-analysis is to describe the incidence, prevalence, and duration of diarrhea in individuals taking LPV/r.

METHODS

This is a meta-analysis of Abbott-conducted clinical trials. Inclusion criteria included prospective randomized clinical trials with the LPV/r tablet formulation and had AE data (moderate/severe diarrhea) available through 48 weeks of treatment.

RESULTS

Three trials (total 1469 participants) met the inclusion criteria. In all, 11.2% of participants reported moderate/severe diarrhea by week 8, with median time to resolution of 7.4 weeks. The overall 48-week incidence of moderate/severe diarrhea was 15.5%. The discontinuation rate due to moderate/severe diarrhea was 1.3%.

CONCLUSIONS

Moderate/severe diarrhea occurred in less than 1 in 6 participants taking LPV/r, typically started in the first 8 weeks of treatment and infrequently resulted in premature discontinuation.

Cost-effective screening for acute hepatitis C virus infection in HIV-infected men who have sex with men

BACKGROUND

We used a Monte Carlo computer simulation to estimate the effectiveness and cost-effectiveness of screening for acute hepatitis C virus (HCV) infection in human immunodeficiency virus (HIV)-infected men who have sex with men.

METHODS

One-time screening for prevalent HCV infection was performed at the time of enrollment in care, followed by either symptom-based screening, screening with liver function tests (LFTs), HCV antibody (Ab) screening, or HCV RNA screening in various combinations and intervals. We considered both treatment with pegylated interferon and ribavirin (PEG/RBV) alone and with an HCV protease inhibitor. Outcome measures were life expectancy, quality-adjusted life expectancy, direct medical costs, and cost-effectiveness, assuming a societal willingness to pay $100000 per quality-adjusted life-year (QALY) gained.

RESULTS

All strategies increased life expectancy (from 0.49 to 0.94 life-months), quality-adjusted life expectancy (from 0.47 to 1.00 quality-adjusted life-months), and costs (from $1900 to $7600), compared with symptom-based screening. The incremental cost-effectiveness ratio of screening with 6-month LFTs and a 12-month HCV Ab test, compared with symptom-based screening, was $43 700/QALY (for PEG/RBV alone) and $57 800/QALY (for PEG/RBV plus HCV protease inhibitor). The incremental cost-effectiveness ratio of screening with 3-month LFTs, compared with 6-month LFTs plus a 12-month HCV Ab test, was $129 700/QALY (for PEG/RBV alone) and $229 900/QALY (for PEG/RBV plus HCV protease inhibitor). With HCV protease inhibitor-based therapy, screening with 6-month LFTs and a 12-month HCV Ab test was the optimal strategy when the HCV infection incidence was ≤1.25 cases/100 person-years. The 3-month LFT strategy was optimal when the incidence was >1.25 cases/100 person-years.

CONCLUSIONS

Screening for acute HCV infection in HIV-infected MSM prolongs life expectancy and is cost-effective. Depending on incidence, regular screening with LFTs, with or without an HCV Ab test, is the optimal strategy.

The cost-effectiveness of pre-exposure prophylaxis for HIV infection in South African women

BACKGROUND

Recent trials report the short-term efficacy of tenofovir-based pre-exposure prophylaxis (PrEP) for prevention of human immunodeficiency virus (HIV) infection. PrEP's long-term impact on patient outcomes, population-level transmission, and cost-effectiveness remains unknown.

METHODS

We linked data from recent trials to a computer model of HIV acquisition, screening, and care to project lifetime HIV risk, life expectancy (LE), costs, and cost-effectiveness, using 2 PrEP-related strategies among heterosexual South African women: (1) women receiving no PrEP and (2) women not receiving PrEP (a tenofovir-based vaginal microbicide). We used a South African clinical cohort and published data to estimate population demographic characteristics, age-adjusted incidence of HIV infection, and HIV natural history and treatment parameters. Baseline PrEP efficacy (percentage reduction in HIV transmission) was 39% at a monthly cost of $5 per woman. Alternative parameter values were examined in sensitivity analyses.

RESULTS

Among South African women, PrEP reduced mean lifetime HIV risk from 40% to 27% and increased population discounted (undiscounted) LE from 22.51 (41.66) to 23.48 (44.48) years. Lifetime costs of care increased from $7280 to $9890 per woman, resulting in an incremental cost-effectiveness ratio of $2700/year of life saved, and may, under optimistic assumptions, achieve cost savings. Under baseline HIV infection incidence assumptions, PrEP was not cost saving, even assuming an efficacy >60% and a cost <$1. At an HIV infection incidence of 9.1%/year, PrEP achieved cost savings at efficacies ≥50%.

CONCLUSIONS

PrEP in South African women is very cost-effective by South African standards, conferring excellent value under virtually all plausible data scenarios. Although optimistic assumptions would be required to achieve cost savings, these represent important benchmarks for future PrEP study design.

Dual therapy based on a ritonavir-boosted protease inhibitor as a novel salvage strategy for HIV-1-infected patients on a failing antiretroviral regimen

OBJECTIVES

To assess the efficacy and safety of dual-antiretroviral therapy containing a ritonavir-boosted protease inhibitor (PI/r) in treatment-experienced patients failing a current antiretroviral regimen.

METHODS

Retrospective analysis of 60 consecutive HIV-1-infected patients who started a dual-antiretroviral rescue regimen containing a PI/r, in three hospitals in Spain. Virological failure was defined as confirmed HIV RNA >50 copies/mL at treatment week 24 or later. The percentage of patients remaining free of therapeutic failure was estimated using the Kaplan-Meier method, by intent-to-treat analysis (missing, changes and virological failure = therapeutic failure).

RESULTS

Median baseline characteristics of patients were: 13 years on antiretroviral therapy (four prior highly active antiretroviral therapy regimens and eight different drugs), 380 CD4 cells/mm(3) and HIV RNA 3.04 log(10) copies/mL. All patients had resistance mutations to at least two drug classes, although only 9.3% had specific mutations to darunavir. A darunavir-based regimen was started in 47 (78.4%) patients, combined with etravirine (26.7%), tenofovir (26.7%) or raltegravir (25%). Three (5%) patients discontinued treatment due to side effects. At the end of follow-up, 86.7% of patients remained free of therapeutic failure; the percentages of patients with no therapeutic failure at treatment weeks 24, 48 and 96 were 96.6% (95% CI, 91.9-101.3); 90.1% (95% CI, 81.9-98.3) and 79.8% (95% CI, 66.1-93.5), respectively.

CONCLUSIONS

Our results suggest that a dual-therapy rescue regimen including a PI/r is convenient, well tolerated and potent enough to achieve persistent viral suppression in selected pre-treated patients with low viral load and few PI resistance mutations.

Newer drugs and earlier treatment: impact on lifetime cost of care for HIV-infected adults

OBJECTIVE

To determine the component costs of care to optimize treatment with limited resources.

DESIGN

We used the Cost-Effectiveness of Preventing AIDS Complications Model of HIV disease and treatment to project life expectancy and both undiscounted and discounted lifetime costs (2010 €).

METHODS

We determined medical resource utilization among HIV-infected adults followed from 1998 to 2005 in northern France. Monthly HIV costs were stratified by CD4 cell count. Costs of CD4, HIV RNA and genotype tests and antiretroviral therapy (ART) were derived from published literature. Model inputs from national data included mean age 38 years, mean initial CD4 cell count 372 cells/μl, ART initiation at CD4 cell counts less than 350 cells/μl, and ART regimen costs ranging from €760 to 2570 per month.

RESULTS

The model projected a mean undiscounted life expectancy of 26.5 years and a lifetime undiscounted cost of €535,000/patient (€320,700 discounted); 73% of costs were ART related. When patients presented to care with mean CD4 cell counts of 510 cells/μl and initiated ART at CD4 cell counts less than 500 cells/μl or HIV RNA more than 100,000 copies/ml, life expectancy was 27.4 years and costs increased 1-2%, to €546,700 (€324,500 discounted). When we assumed introducing generic drugs would result in a 50% decline in first-line ART costs, lifetime costs decreased 4-6%, to €514,200 (€302 ,800 discounted).

CONCLUSION

As HIV disease is treated earlier with more efficacious drugs, survival and thus costs of care will continue to increase. The availability in high-income countries of widely used antiretroviral drugs in generic form could reduce these costs.

Economic and health-related quality-of-life (HRQoL) comparison of lopinavir/ritonavir (LPV/r) and atazanavir plus ritonavir (ATV+RTV) based regimens for antiretroviral therapy (ART)-naïve and -experienced United Kingdom patients in 2011

BACKGROUND

Using a United Kingdom (UK)-based National Health Services perspective for 2011 this study first estimated the cost-effectiveness and budget impact implications for lopinavir/ritonavir (LPV/r) vs atazanavir plus ritonavir (ATV+RTV) treatment of antiretroviral therapy (ART)-naïve patients and secondly examined the long-term health-related quality-of-life (HRQoL) and economic implications for LPV/r vs ATV+RTV treatment of ART-experienced patients.

METHODS

A previously published Markov model that integrates epidemiological data of human immunodeficiency virus (HIV) with predictors of coronary heart disease (CHD) was modified under a clearly specified set of assumptions to reflect viral load (VL) suppression profiles and other differences for these two regimens, applying results from the CASTLE study in ART-naïve patients and using data from BMS-045 in ART-experienced patients. ART costs were referenced to current (2011) pricing guidelines in the UK. Medical care costs reflected UK treatment patterns and relevant drug pricing. Costs and outcomes were discounted at 3.5% per year. Costs are expressed in British pounds (£) and life expectancy in quality-adjusted life years (QALYs).

RESULTS

In the ART-naïve subjects, the model predicted a marginal improved life expectancy of 0.031 QALYs (11 days) for the ATV+RTV regimen as a result of predicted CHD outcomes based on lower increases in cholesterol levels compared with the LPV/r regimen. The model demonstrated cost savings with the LPV/r regimen. The total lifetime cost savings was £4070 per patient for the LPV/r regimen. LPV/r saved £2133 and £3409 per patient at 5 and 10 years, respectively. Referenced to LPV/r, the incremental cost-effectiveness ratio (ICER) for ATV+RTV was £149,270/QALY. For ART-experienced patients VL suppression differences favored LPV/r, while CHD risk associated with elevated total cholesterol marginally favored ATV+RTV, resulting in a net improvement in life expectancy of 0.31 QALYs (106 days) for LPV/r. Five-year costs were £5538 per patient greater for ATV+RTV, with a discounted lifetime saving of £1445 per LPV/r patient. LPV/r was modestly dominant economically, producing better outcomes and cost savings.

LIMITATIONS

The limitations of this study include uncertainty related to how well the model's assumptions capture current practice, as well as the validity of the model parameters used. This study was limited to using aggregated data in the public domain from the two clinical trials. Thus, some of the model parameters may reflect limitations due to trial design and data aggregation bias. This study has attempted to illuminate the effect of these limitations by presenting the results of the comprehensive sensitivity analysis.

CONCLUSIONS

Based on 2011 costs of HIV in the UK and the published efficacy data from the CASTLE and BMS-045 studies, ATV+RTV-based regimens are not expected to be a cost-effective use of resources for ART-naïve patients similar to patients in the CASTLE study, nor for ART-experienced patients based on the only published comparison of ATV+RTV and LPV/r.