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

Comparative manufacture and cell-based delivery of antiretroviral nanoformulations

Nanoformulations of crystalline indinavir, ritonavir, atazanavir, and efavirenz were manufactured by wet milling, homogenization or sonication with a variety of excipients. The chemical, biological, immune, virological, and toxicological properties of these formulations were compared using an established monocyte-derived macrophage scoring indicator system. Measurements of drug uptake, retention, release, and antiretroviral activity demonstrated differences amongst preparation methods. Interestingly, for drug cell targeting and antiretroviral responses the most significant difference among the particles was the drug itself. We posit that the choice of drug and formulation composition may ultimately affect clinical utility.

Resource utilization and cost-effectiveness of counselor- vs. provider-based rapid point-of-care HIV screening in the emergency department

Background

Routine HIV screening in emergency department (ED) settings may require dedicated personnel. We evaluated the outcomes, costs and cost-effectiveness of HIV screening when offered by either a member of the ED staff or by an HIV counselor.

Methods

We employed a mathematical model to extend data obtained from a randomized clinical trial of provider- vs. counselor-based HIV screening in the ED. We compared the downstream survival, costs, and cost-effectiveness of three HIV screening modalities: 1) no screening program; 2) an ED provider-based program; and 3) an HIV counselor-based program. Trial arm-specific data were used for test offer and acceptance rates (provider offer 36%, acceptance 75%; counselor offer 80%, acceptance 71%). Undiagnosed HIV prevalence (0.4%) and linkage to care rates (80%) were assumed to be equal between the screening modalities. Personnel costs were derived from trial-based resource utilization data. We examined the generalizability of results by conducting sensitivity analyses on offer and acceptance rates, undetected HIV prevalence, and costs.

Results

Estimated HIV screening costs in the provider and counselor arms averaged $8.10 and $31.00 per result received. The Provider strategy (compared to no screening) had an incremental cost-effectiveness ratio of $58,700/quality-adjusted life year (QALY) and the Counselor strategy (compared to the Provider strategy) had an incremental cost-effectiveness ratio of $64,500/QALY. Results were sensitive to the relative offer and acceptance rates by strategy and the capacity of providers to target-screen, but were robust to changes in undiagnosed HIV prevalence and programmatic costs.

Conclusions

The cost-effectiveness of provider-based HIV screening in an emergency department setting compares favorably to other US screening programs. Despite its additional cost, counselor-based screening delivers just as much return on investment as provider based-screening. Investment in dedicated HIV screening personnel is justified in situations where ED staff resources may be insufficient to provide comprehensive, sustainable screening services.

Peripheral and central fat changes in subjects randomized to abacavir-lamivudine or tenofovir-emtricitabine with atazanavir-ritonavir or efavirenz: ACTG Study A5224s

BACKGROUND

We compare the effect of 4 different antiretroviral regimens on limb and visceral fat.

METHODS

A5224s was a substudy of A5202, a trial of human immunodeficiency virus type 1 (HIV-1)-infected, treatment-naive subjects randomized to blinded abacavir-lamivudine (ABC-3TC) or tenofovir DF-emtricitabine (TDF-FTC) with open-label efavirenz (EFV) or atazanavir-ritonavir (ATV-r). The primary endpoint was the presence of lipoatrophy (≥ 10% loss of limb fat) at week 96 by intent-to-treat (ITT) analysis. Secondary endpoints included changes in limb and visceral fat. Statistical tests included linear regression, binomial, two-sample t test, and Fisher's exact test.

RESULTS

A5224s enrolled 269 subjects; 85% were male, and 47% were white non-Hispanic. The subjects had a median baseline HIV-1 RNA level of 4.6 log(10) copies/mL, a median age of 38 years, a median CD4+ cell count of 233 cells/μL, median limb fat of 7.4 kg, median visceral adipose tissue (VAT) of 84.1 cm(2), and VAT: total adipose tissue (TAT) ratio of 0.31. At week 96, estimated prevalence of lipoatrophy (upper 95% confidence interval [CI]) was 18% (25%) for ABC-3TC and 15% (22%) for TDF-FTC (P = .70); this was not significantly less than the hypothesized 15% for both (P ≥ .55 for both). The secondary as-treated (AT) analysis showed similar results. At week 96, the estimated mean percentage change from baseline in VAT was higher for the ATV-r group than for the EFV group (26.6% vs 12.4%; P = .090 in ITT analysis and 30.0% vs 14.5%; P = .10 in AT analysis); however, the percentage change in VAT:TAT was similar by ITT and AT analysis (P ≥ .60 for both). Results were similar for absolute changes in VAT and VAT:TAT.

CONCLUSIONS

ABC-3TC- and TDF-FTC-based regimens increased limb and visceral fat at week 96, with a similar prevalence of lipoatrophy. Compared to the EFV group, subjects assigned to ATV-r had a trend towards higher mean percentage increase in VAT.

CLINICAL TRIALS REGISTRATION

NCT00118898.

Atazanavir and atazanavir/ritonavir pharmacokinetics in HIV-infected infants, children, and adolescents

OBJECTIVE

To describe the pharmacokinetics of atazanavir (ATV) and ritonavir-boosted ATV (ATV/r) in children aged 91 days to 21 years.

DESIGN

A phase I/II, open-label, multicenter study of once-daily ATV and ATV/r as part of combination antiretroviral treatment in HIV-infected treatment-experienced and treatment-naive children.

SETTING

Sites in the United States and South Africa.

PARTICIPANTS

One hundred and ninety-five children enrolled; 172 had evaluable ATV pharmacokinetics on day 7.

INTERVENTION

Children were entered in age, dose, and formulation (powder or capsule) cohorts. Intensive pharmacokinetic sampling occurred 7 days after starting ATV. ATV doses were increased or decreased if the 24-h area under the concentration time curves (AUC0-24hr) were less than 30 or more than 90 μg × h/ml, respectively.

MAIN OUTCOMES

Cohorts satisfied protocol-defined pharmacokinetic criteria if the median ATV AUC0-24hr was 60 μg × h/ml or less, and AUC0-24hr and ATV concentrations 24-h postdose (C24) were more than 30 μg × h/ml and at least 60 ng/ml, respectively, in at least 80% of the children, with no individual AUC0-24hr less than 15 μg × h/ml.

RESULTS

Unboosted ATV capsules satisfied pharmacokinetic criteria at a dose of 520 mg/m for those aged more than 2 to 13 years or less and 620 mg/m for those aged more than 13 to 21 years or less. ATV/r capsules satisfied criteria at a dose of 205 mg/m for those aged more than 2 to 21 years or less. ATV/r powder satisfied criteria at a dose of 310 mg/m for those aged more than 2 to 13 years or less, but pharmacokinetics in those aged 2 years or less were highly variable.

CONCLUSION

Body surface area-determined doses of ATV capsules and of ATV/r powder and capsules provide ATV exposures in children of more than 2 years that approximate concentrations in adults receiving ATV/r.

Severe skin rash associated with atazanavir

Three cases of severe rash associated with the use of atazanavir are described. In all cases, the rash was maculopapular and pruritic. Rash onset occurred eight to 11 days after initiation of therapy, and resolved with atazanavir discontinuation. Clinicians prescribing atazanavir should be aware of this potential adverse effect.

Projected survival gains from revising state laws requiring written opt-in consent for HIV testing

BACKGROUND

Although the Centers for Disease Control and Prevention recommends HIV testing in all settings unless patients refuse (opt-out consent), many state laws require written opt-in consent.

OBJECTIVE

To quantify potential survival gains from passing state laws streamlining HIV testing consent.

DESIGN

We retrieved surveillance data to estimate the current annual HIV diagnosis rate in states with laws requiring written opt-in consent (19.3%). Published data informed the effect of removing that requirement on diagnosis rate (48.5% increase). These parameters then served as input for a model-driven projection of survival based on consent method. Other inputs included undiagnosed HIV prevalence (0.101%); and annual HIV incidence (0.023%).

PATIENTS

Hypothetical cohort of adults (>13 years) living in written opt-in states.

MEASUREMENTS

Life years gained (LYG).

RESULTS

In the base-case, of the 53,036,383 adult persons living in written opt-in states, 0.66% (350,040) will be infected with HIV. Due to earlier diagnosis, revised consent laws yield 1.5 LYG per HIV-infected person, corresponding to 537,399 LYG among this population. Sensitivity analyses demonstrate that diagnosis rate increases of 24.8-72.3% result in 304,765-724,195 LYG. Net survival gains vanish if the proportion of HIV-infected persons refusing all testing in response to revised laws exceeds 18.2%.

CONCLUSIONS

The potential survival gains of increased testing are substantial, suggesting that state laws requiring opt-in HIV testing should be revised.

The use of atazanavir in HIV-infected patients with liver cirrhosis: lack of hepatotoxicity and no significant changes in bilirubin values or model for end-stage liver disease score

Although atazanavir is widely used in hepatitis C virus (HCV)-HIV-1 patients, little is known about its safety in advanced liver disease. We studied 34 HCV-HIV-1 patients with cirrhosis receiving atazanavir. After 551.2 patient-months of follow-up, there were no cases of serious liver toxicity or cirrhosis decompensation, and only 18.5% discontinued the drug. Despite median bilirubin level at inclusion was 1.5 mg/ml, increases in bilirubin level were mild. Model for end-stage liver disease score (MELD) increased to 1.35 points (95% confidence interval 0.13-2.6), but no patient changed their pretreatment situation after atazanavir introduction. Atazanavir is a well tolerated option in cirrhosis, and significant alterations in bilirubin or MELD were not observed.

Changes in lipid profiles after switching to a protease inhibitor-containing cART--unfavourable effect of fosamprenavir in obese patients

OBJECTIVE

One focus in the medical care of HIV-infected patients today is cardiovascular risk reduction. Metabolic disturbances occur frequently in patients taking protease inhibitors (PI) and are a major risk factor for atherosclerosis. With few published head-to-head studies substance-specific differences concerning metabolic effects are insufficiently defined. Therefore this cohort study directly compared the metabolic profiles of boosted atazanavir (ATV/r), fosamprenavir (FPV/r) and saquinavir (SQV/r).

METHODS

Data from a cohort of 124 HIV patients initiating a boosted regimen with one of the PIs at the University of Munich (LMU) infectious diseases outpatient clinic were retrospectively analyzed. The main outcome measures were median absolute total cholesterol levels and median relative change of total cholesterol levels after six months of PI-therapy. A multivariate linear regression model was built to identify and control for potential confounders of the association between PI-therapy and serum cholesterol level.

RESULTS

84 patients were treated with ATV/r, 23 patients received FPV/r and 17 patients SQV/r. Demographically the cohort constituted a representative sample of HIV-infected patients in Germany. There were no statistically significant differences between the comparison groups at baseline. - After six months of therapy median serum cholesterol in the ATV/r group dropped significantly from 204 mg/dl to 186 mg/dl, while in the FPV/r and SQV/r groups a rise in serum cholesterol levels was observed from 179 mg/dl to 204 mg/dl and from 173 mg/dl to 209 mg/dl respectively. The multivariate linear regression model identified a significant interaction between BMI at baseline and treatment with FPV/r: patients with higher BMI showed more prominent increases in serum cholesterol while taking FPV/r compared to patients with lower BMI.

CONCLUSION

This cohort study demonstrated the most favourable impact on serum cholesterol levels and thus cardiovascular risk for ATV/r compared to FPV/r and SQV/r under real-life conditions. Given the statistical interaction detected between FPV/r and BMI further studies assessing metabolic profiles of different antiretroviral drugs in specific patient populations are urgently needed.

First-line antiretroviral therapy after single-dose nevirapine exposure in South Africa: a cost-effectiveness analysis of the OCTANE trial

BACKGROUND

The OCTANE trial reports superior outcomes of lopinavir/ritonavir vs. nevirapine-based antiretroviral therapy (ART) among women previously exposed to single-dose nevirapine to prevent mother-to-child HIV transmission. However, lopinavir/ritonavir is 12 times costlier than nevirapine.

METHODS

We used a computer model, with OCTANE and local data, to simulate HIV-infected, single-dose nevirapine-exposed women in South Africa. Outcomes of three alternative ART sequences were projected: no ART (for comparison), first-line nevirapine, and first-line lopinavir/ritonavir. OCTANE data included mean age (31 years) and CD4 cell count (135/μl); median time since single-dose nevirapine (17 months); and 24-week viral suppression efficacy for first-line ART (nevirapine: 85%, lopinavir/ritonavir: 97%). Outcomes included life expectancy, per-person costs (2008 US$), and incremental cost-effectiveness ratios.

RESULTS

With no ART, projected life expectancy was 1.6 years and per-person cost was $2980. First-line nevirapine increased life expectancy (15.2 years) and cost ($13 990; cost-effectiveness ratio: $810/year of life saved versus no ART). First-line lopinavir/ritonavir further increased life expectancy to 16.3 years and cost to $15 630 (cost-effectiveness ratio: $1520/year of life saved versus first-line nevirapine). First-line lopinavir/ritonavir cost-effectiveness was sensitive to prevalence of nevirapine-resistant virus at ART initiation, time from single-dose nevirapine exposure to ART initiation (6-12, 12-24, or >24 months), second-line ART efficacies, and outcomes after 24 weeks on ART.

CONCLUSIONS

First-line lopinavir/ritonavir-based ART is very cost-effective in single-dose nevirapine-exposed, South African women similar to OCTANE participants. Lopinavir/ritonavir should be initiated in women with known nevirapine resistance or single-dose nevirapine exposure less than 12 months prior, or in whom such information is unknown.

Quantifying the risks and benefits of efavirenz use in HIV-infected women of childbearing age in the USA

OBJECTIVES

The aim of the study was to quantify the benefits (life expectancy gains) and risks (efavirenz-related teratogenicity) associated with using efavirenz in HIV-infected women of childbearing age in the USA.

METHODS

We used data from the Women's Interagency HIV Study in an HIV disease simulation model to estimate life expectancy in women who receive an efavirenz-based initial antiretroviral regimen compared with those who delay efavirenz use and receive a boosted protease inhibitor-based initial regimen. To estimate excess risk of teratogenic events with and without efavirenz exposure per 100,000 women, we incorporated literature-based rates of pregnancy, live births, and teratogenic events into a decision analytic model. We assumed a teratogenicity risk of 2.90 events/100 live births in women exposed to efavirenz during pregnancy and 2.68/100 live births in unexposed women.

RESULTS

Survival for HIV-infected women who received an efavirenz-based initial antiretroviral therapy (ART) regimen was 0.89 years greater than for women receiving non-efavirenz-based initial therapy (28.91 vs. 28.02 years). The rate of teratogenic events was 77.26/100,000 exposed women, compared with 72.46/100,000 unexposed women. Survival estimates were sensitive to variations in treatment efficacy and AIDS-related mortality. Estimates of excess teratogenic events were most sensitive to pregnancy rates and number of teratogenic events/100 live births in efavirenz-exposed women.

CONCLUSIONS

Use of non-efavirenz-based initial ART in HIV-infected women of childbearing age may reduce life expectancy gains from antiretroviral treatment, but may also prevent teratogenic events. Decision-making regarding efavirenz use presents a trade-off between these two risks; this study can inform discussions between patients and health care providers.

Early antiretroviral therapy for patients with acute aids-related opportunistic infections: a cost-effectiveness analysis of ACTG A5164

PURPOSE

ACTG A5164 demonstrated that early antiretroviral therapy (ART) in HIV-infected patients with acute opportunistic infections (OIs) reduced death and AIDS progression compared to ART initiation 1 month later. We project the life expectancies, costs, and incremental cost-effectiveness ratios (ICERs) of these strategies.

METHOD

using an HIV simulation model, we compared 2 strategies for patients with acute OIs: (1) an intervention to deliver early ART, and (2) deferred ART. Parameters from ACTG A5164 included initial mean CD4 count (47/microL), linkage to outpatient care (87%), and immune reconstitution inflammatory syndrome 1 month after ART initiation (7%). The estimated intervention cost was $1,650/patient.

RESULTS

early ART lowered projected 1-year mortality from 10.4% to 8.2% and increased life expectancy from 10.07 to 10.39 quality-adjusted life-years (QALYs). Lifetime costs increased from $385,220 with deferred ART to $397,500 with early ART, primarily because life expectancy increased, producing an ICER of $38,600/QALY. Results were most sensitive to increased intervention cost and decreased virologic efficacy in the early ART strategy.

CONCLUSIONS

an intervention to initiate ART early in patients with acute OIs improves survival and meets US cost-effectiveness thresholds. Programs should be developed to implement this strategy at sites where HIV-infected patients present with OIs.

Cost effectiveness of atazanavir-ritonavir versus lopinavir-ritonavir in treatment-naïve human immunodeficiency virus-infected patients in the United States

OBJECTIVE

To evaluate lifetime cost effectiveness of atazanavir-ritonavir (ATV + r) versus lopinavir-ritonavir (LPV/r), both with tenofovir-emtricitabine, in US HIV-infected patients initiating first-line antiretroviral therapy.

METHODS

A Markov microsimulation model was developed to calculate quality-adjusted life-years (QALYs) based on CD4 and HIV RNA levels, coronary heart disease (CHD), AIDS, opportunistic infections (OIs), diarrhea, and hyperbilirubinemia. A million-member cohort of HIV-1-infected, treatment-naïve adults progressed at 3-month intervals through eight health states. Baseline characteristics, virologic suppression, cholesterol changes, and diarrhea and hyperbilirubinemia rates were based on 96-week CASTLE trial results. HIV mortality, OI rates, adherence, costs, utilities, and CHD risk were from literature and experts.

LIMITATIONS

The incremental cost-effectiveness ratio (ICER) may be overestimated because the ATV + r treatment effect was based on an intention-to-treat analysis. The QALY weights used for diarrhea, hyperbilirubinemia, and CHD events are uncertain; however, the ICER remained < $50,000/QALY when these values were varied in sensitivity analyses.

RESULTS

ATV + r patients received first-line therapy longer than LPV/r patients (97.3 vs. 70.7 months), had longer quality-adjusted survival (11.02 vs. 10.76 years), similar overall survival (18.52 vs. 18.51 years), and higher costs ($275,986 vs. 269,160). ATV+r [corrected] patients had lower rates of AIDS (19.08 vs. 20.05 cases/1000 patient-years), OIs (0.44 vs.0.52), diarrhea (1.27 vs. 6.26), and CHD events(5.44 vs. 5.51), but higher hyperbilirubinemia rates (6.99 vs. 0.25. ATV + r added 0.26 QALYs at a cost of $6826, for $26,421/QALY.

CONCLUSIONS

By more effectively reducing viral load with less gastrointestinal toxicity and a better lipid profile, ATV + r lowered rates of AIDS and CHD, increased quality-adjusted survival, and was cost effective (< $50,000/QALY) compared with LPV/r.

Importance of P-glycoprotein for drug-drug interactions

P-glycoprotein (ABCB1) is one of the most extensively studied transporters regarding drug resistance and drug-drug interactions. P-glycoprotein is expressed in multiple key organs in drug disposition such as small intestine, blood-brain barrier, kidney, and liver. Therefore, P-glycoprotein mediated drug-drug interactions can occur at various organs and tissues. This chapter will mainly focus on drug-drug interactions that are mediated by the intestinal P-glycoprotein.During the last decade, many in vitro and in vivo studies reported that the induction or inhibition of P-glycoprotein can lead to drug-drug interactions. For instance, induction of the intestinal P-glycoprotein activity can cause reduced bioavailability of orally administered drugs and decreased therapeutic efficacy. On the other hand, the inhibition of the intestinal P-glycoprotein activity can lead to increased bioavailability, thus leading to an increased risk of adverse side effects.

Lopinavir/Ritonavir: a review of its use in the management of HIV-1 infection

Lopinavir/ritonavir (Kaletra®) is an orally administered coformulated ritonavir-boosted protease inhibitor (PI) comprising lopinavir and low-dose ritonavir. It is indicated, in combination with other antiretroviral agents, for the treatment of HIV-1 infection in adults, adolescents and children. Lopinavir/ritonavir is available as a tablet, soft-gel capsule and an oral solution for patients with difficulty swallowing. In well designed, randomized clinical trials, lopinavir/ritonavir, in combination with other antiretroviral therapies (ART), provided durable virological suppression and improved immunological outcomes in both ART-naive and -experienced adult patients with virological failure. Furthermore, lopinavir/ritonavir demonstrated a high barrier to the development of resistance in ART-naive patients. More limited data indicate that it is effective in reducing plasma HIV-1 RNA levels in paediatric patients. Lopinavir/ritonavir has served as a well established benchmark comparator for the noninferiority of other ritonavir-boosted PI regimens. Although generally well tolerated, lopinavir/ritonavir is associated with generally manageable adverse gastrointestinal side effects and hypertriglyceridaemia and hypercholesterolaemia, which may require coadministration of lipid-lowering agents to reduce the risk of coronary heart disease. Lopinavir/ritonavir, in combination with other ART agents, is a well established and cost-effective treatment for both ART-naive and -experienced patients with HIV-1 infection and, with successful management of adverse events, continues to have a role as an effective component of ART regimens for the control of HIV-1 infection.

Nanoformulated antiretroviral drug combinations extend drug release and antiretroviral responses in HIV-1-infected macrophages: implications for neuroAIDS therapeutics

We posit that improvements in pharmacokinetics and biodistributions of antiretroviral therapies (ART) for human immunodeficiency virus type one-infected people can be achieved through nanoformulationed drug delivery systems. To this end, we manufactured nanoparticles of atazanavir, efavirenz, and ritonavir (termed nanoART) and treated human monocyte-derived macrophages (MDM) in combination therapies to assess antiretroviral responses. This resulted in improved drug uptake, release, and antiretroviral efficacy over monotherapy. MDM rapidly, within minutes, ingested nanoART combinations, at equal or similar rates, as individual formulations. Combination nanoART ingested by MDM facilitated individual drug release from 15 to >20 days. These findings are noteworthy as a nanoART cell-mediated drug delivery provides a means to deliver therapeutics to viral sanctuaries, such as the central nervous system during progressive human immunodeficiency virus type one infection. The work brings us yet another step closer to realizing the utility of nanoART for virus-infected people.

Outcomes of patients on dual-boosted PI regimens: experience of the Swiss HIV cohort study

Dual-boosted protease inhibitors (DBPI) are an option for salvage therapy for HIV-1 resistant patients. Patients receiving a DBPI in the Swiss HIV Cohort Study between January1996 and March 2007 were studied. Outcomes of interest were viral suppression at 24 weeks. 295 patients (72.5%) were on DBPI for over 6 months. The median duration was 2.2 years. Of 287 patients who had HIV-RNA >400 copies/ml at the start of the regimen, 184 (64.1%) were ever suppressed while on DBPI and 156 (54.4%) were suppressed within 24 weeks. The median time to suppression was 101 days (95% confidence interval 90-125 days). The median number of past regimens was 6 (IQR, 3-8). The main reasons for discontinuing the regimen were patient's wish (48.3%), treatment failure (22.5%), and toxicity (15.8%). Acquisition of HIV through intravenous drug use and the use of lopinavir in combination with saquinavir or atazanavir were associated with an increased likelihood of suppression within 6 months. Patients on DBPI are heavily treatment experienced. Viral suppression within 6 months was achieved in more than half of the patients. There may be a place for DBPI regimens in settings where more expensive alternates are not available.

HIV protease inhibitors and obesity

PURPOSE OF REVIEW

To review the current scientific literature and recent clinical trials on HIV protease inhibitors and their potential role in the pathogenesis of lipodystrophy and metabolic disorders.

RECENT FINDINGS

HIV protease inhibitor treatment may affect the normal stimulatory effect of insulin on glucose and fat storage. Further, chronic inflammation from HIV infection and protease inhibitor treatment trigger cellular homeostatic stress responses with adverse effects on intermediary metabolism. The physiologic outcome is such that total adipocyte storage capacity is decreased, and the remaining adipocytes resist further fat storage. This process leads to a pathologic cycle of lipodystrophy and lipotoxicity, a proatherogenic lipid profile, and a clinical phenotype of increased central body fat distribution similar to the metabolic syndrome.

SUMMARY

Protease inhibitors are a key component of antiretroviral therapy and have dramatically improved the life expectancy of HIV-infected individuals. However, they are also associated with abnormalities in glucose/lipid metabolism and body fat distribution. Further studies are needed to better define the pathogenesis of protease inhibitor-associated metabolic and body fat changes and their potential treatment.

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

BACKGROUND

In France, roughly 40,000 HIV-infected persons are unaware of their HIV infection. Although previous studies have evaluated the cost-effectiveness of routine HIV screening in the United States, differences in both the epidemiology of infection and HIV testing behaviors warrant a setting-specific analysis for France.

METHODS/PRINCIPAL FINDINGS

We estimated the life expectancy (LE), cost and cost-effectiveness of alternative HIV screening strategies in the French general population and high-risk sub-populations using a computer model of HIV detection and treatment, coupled with French national clinical and economic data. We compared risk-factor-based HIV testing ("current practice") to universal routine, voluntary HIV screening in adults aged 18-69. Screening frequencies ranged from once to annually. Input data included mean age (42 years), undiagnosed HIV prevalence (0.10%), annual HIV incidence (0.01%), test acceptance (79%), linkage to care (75%) and cost/test (€43). We performed sensitivity analyses on HIV prevalence and incidence, cost estimates, and the transmission benefits of ART. "Current practice" produced LEs of 242.82 quality-adjusted life months (QALM) among HIV-infected persons and 268.77 QALM in the general population. Adding a one-time HIV screen increased LE by 0.01 QALM in the general population and increased costs by €50/person, for a cost-effectiveness ratio (CER) of €57,400 per quality-adjusted life year (QALY). More frequent screening in the general population increased survival, costs and CERs. Among injection drug users (prevalence 6.17%; incidence 0.17%/year) and in French Guyana (prevalence 0.41%; incidence 0.35%/year), annual screening compared to every five years produced CERs of €51,200 and €46,500/QALY.

CONCLUSIONS/SIGNIFICANCE

One-time routine HIV screening in France improves survival compared to "current practice" and compares favorably to other screening interventions recommended in Western Europe. In higher-risk groups, more frequent screening is economically justifiable.

Incidence of atazanavir-associated hyperbilirubinemia in Korean HIV patients: 30 months follow-up results in a population with low UDP-glucuronosyltransferase1A1*28 allele frequency

Hyperbilirubinemia is frequently observed in Caucasian HIV patients treated with atazanavir. UDP-glucuronosyltransferase 1A1 polymorphism, UGT1A1*28, which is associated with atazanavir-induced hyperbilirubinemia, is less common in Asians than in Caucasians. However, little is known about the incidence of atazanavir-associated hyperbilirubinemia in Asian populations. Our objective was to investigate the incidence of and tolerability of atazanavir-associated hyperbilirubinemia in Korean HIV patients. The prevalence and cumulative incidence of atazanavir-associated hyperbilirubinemia and UGT1A1*28 allele frequency was investigated in 190 Korean HIV-infected patients treated with atazanavir 400 mg per day. The UGT1A1*28 were examined by direct sequencing of DNA from peripheral whole blood. The UGT1A1*28 allele frequency was 11%. The cumulative incidence of any grade of hyperbilirubinemia was 77%, 89%, 98%, and 100%, at 3, 12, 24, and 30 months, respectively. The cumulative incidence of severe (grade 3-4) hyperbilirubinemia was 21%, 41%, 66%, and 75%, at 3, 12, 24, and 30 months, respectively. However, the point prevalence of severe hyperbilirubinemia did not increase with time and remained around 25%. Our data suggest that atazanavir-associated hyperbilirubinemia is common but transient in a population with low UGT1A1*28 allele frequency.

Assessing the performance of a computer-based policy model of HIV and AIDS

Background

Model-based analyses, conducted within a decision analytic framework, provide a systematic way to combine information about the natural history of disease and effectiveness of clinical management strategies with demographic and epidemiological characteristics of the population. Among the challenges with disease-specific modeling include the need to identify influential assumptions and to assess the face validity and internal consistency of the model.

Methods and Findings

We describe a series of exercises involved in adapting a computer-based simulation model of HIV disease to the Women's Interagency HIV Study (WIHS) cohort and assess model performance as we re-parameterized the model to address policy questions in the U.S. relevant to HIV-infected women using data from the WIHS. Empiric calibration targets included 24-month survival curves stratified by treatment status and CD4 cell count. The most influential assumptions in untreated women included chronic HIV-associated mortality following an opportunistic infection, and in treated women, the ‘clinical effectiveness’ of HAART and the ability of HAART to prevent HIV complications independent of virologic suppression. Good-fitting parameter sets required reductions in the clinical effectiveness of 1^st and 2^nd line HAART and improvements in 3^rd and 4^th line regimens. Projected rates of treatment regimen switching using the calibrated cohort-specific model closely approximated independent analyses published using data from the WIHS.

Conclusions

The model demonstrated good internal consistency and face validity, and supported cohort heterogeneities that have been reported in the literature. Iterative assessment of model performance can provide information about the relative influence of uncertain assumptions and provide insight into heterogeneities within and between cohorts. Description of calibration exercises can enhance the transparency of disease-specific models.

Laboratory monitoring to guide switching antiretroviral therapy in resource-limited settings: clinical benefits and cost-effectiveness

BACKGROUND

As second-line antiretroviral therapy (ART) availability increases in resource-limited settings, questions about the value of laboratory monitoring remain. We assessed the outcomes and cost-effectiveness (CE) of laboratory monitoring to guide switching ART.

METHODS

We used a computer model to project life expectancy and costs of different strategies to guide ART switching in patients in Côte d'Ivoire. Strategies included clinical assessment, CD4 count, and HIV RNA testing. Data were from clinical trials and cohort studies from Côte d'Ivoire and the literature. Outcomes were compared using the incremental CE ratio. We conducted multiple sensitivity analyses to assess uncertainty in model parameters.

RESULTS

Compared with first-line ART only, second-line ART increased life expectancy by 24% with clinical monitoring only, 46% with CD4 monitoring, and 61% with HIV RNA monitoring. The incremental CE ratio of switching based on clinical monitoring was $1670 per year of life gained (YLS) compared with first-line ART only; biannual CD4 monitoring was $2120 per YLS. The CE ratio of biannual HIV RNA testing ranged from $2920 ($87/test) to $1990 per YLS ($25/test). If second-line ART costs were reduced, the CE of HIV RNA monitoring improved.

CONCLUSIONS

In resource-limited settings, CD4 count and HIV RNA monitoring to guide switching to second-line ART improve survival and, under most conditions, are cost-effective.

Factors predictive of virological failure on atazanavir in 310 HIV-infected patients

We examined factors associated with virological failure in 310 HIV-infected patients receiving atazanavir (ATV). Independent links were identified with virological failure under ATV: virological failure previous history (P = 0.006) and ATV underdosing (P = 0.04). A maintenance therapy was protective (P = 0.01). The optimal therapeutic ranges of ATV concentration were found to be from 300 ng/ml (or 180 for patients treated with maintenance therapy) to 650 ng/ml for C24 and from 1000 ng/ml (or 500 for patients treated with maintenance therapy) to 2000 ng/ml for C12.

Lipid profiles in HIV-infected adults receiving atazanavir and atazanavir/ritonavir: systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To compare lipid profiles in HIV-infected adults receiving atazanavir-based regimens.

METHODS

We conducted a systematic review of randomized controlled trials (RCTs) comparing atazanavir or atazanavir/ritonavir with a comparator and evaluated lipids at 48 weeks. We searched MEDLINE, EMBASE, CENTRAL, LILACS, Current Controlled Trials, National Institutes of Health Clinical Trials Registry, trials at AIDSinfo and HIV conference proceedings to May 2009. Standardized mean difference (SMD) between study arms in change from baseline to week 48 in lipid parameters was determined weighted by study size and 95% confidence intervals (CI) were calculated.

RESULTS

Nine eligible RCTs were identified (n = 3346). SMDs (mmol/L) in four RCTs comparing atazanavir/ritonavir with a ritonavir-boosted protease inhibitor were: total cholesterol, -0.62 (95% CI -0.72, -0.51); low-density lipoprotein (LDL) cholesterol, -0.31 (95% CI -0.44, -0.17); high-density lipoprotein (HDL) cholesterol, -0.16 (95% CI -0.27, -0.06); non-HDL cholesterol, -0.58 (95% CI -0.69, -0.48); and triglycerides, -0.46 (95% CI -0.58, -0.34). Atazanavir compared with non-atazanavir (three RCTs) found lower total, LDL and non-HDL cholesterol, and triglycerides [SMD -0.87 mmol/L (95% CI -0.99, -0.76); -0.56 mmol/L (95% CI -0.67, -0.45); -0.88 mmol/L (95% CI -0.99, -0.76); and -0.56 mmol/L (95% CI -0.75, -0.36), respectively], but HDL cholesterol did not differ [-0.16 mmol/L (95% CI -0.49, 0.16)]. In the atazanavir/ritonavir versus atazanavir comparison (two RCTs), total [SMD 0.44 mmol/L (95% CI 0.23, 0.65)] and non-HDL cholesterol [SMD 0.44 mmol/L (95% CI 0.23, 0.65)] were higher, but HDL cholesterol, LDL cholesterol and triglycerides were not different.

CONCLUSIONS

At 48 weeks, plasma lipid concentrations were lower with atazanavir/ritonavir than with other ritonavir-boosted protease inhibitor regimens. Total and non-HDL cholesterol were higher with atazanavir/ritonavir than atazanavir alone.

Similar safety and efficacy of once- and twice-daily lopinavir/ritonavir tablets in treatment-experienced HIV-1-infected subjects at 48 weeks

OBJECTIVES

To compare the safety and antiviral activity of once (QD) or twice (BID) daily lopinavir/ritonavir (LPV/r) in combination with investigator-selected nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) in treatment-experienced subjects.

METHODS

Subjects failing treatment with HIV-1 RNA > 1000 copies per milliliter received LPV/r tablets 800/200 mg QD (n = 300) or 400/100 mg BID (n = 299) with investigator-chosen nucleoside/nucleotide reverse transcriptase inhibitors. Efficacy was determined by the intent-to-treat time to loss of virologic response (ITT-TLOVR) algorithm. Safety, tolerability, adherence, impact of baseline protease mutations on virologic response, and emergence of resistance on therapy were assessed.

RESULTS

Demographics were comparable across groups. By intent-to-treat time to loss of virologic response, 166 QD subjects (55.3%) and 155 BID subjects (51.8%) were responders at week 48 (P = 0.413), with similar mean increases in CD4 T-cell count. QD subjects demonstrated better adherence than BID subjects. The occurrence of treatment-related moderate/severe adverse events was comparable for all events except nausea, which was reported more frequently among BID-treated subjects. Emergence of new protease resistance mutations on treatment was similarly infrequent in both groups.

CONCLUSION

LPV/r dosed QD resulted in increased treatment adherence and was as efficacious as BID LPV/r while providing similar safety, tolerability, and limited resistance evolution.

Methodological issues in the use of composite endpoints in clinical trials: examples from the HIV field

BACKGROUND

In many fields, the choice of a primary endpoint for a trial is not always the ultimate clinical endpoint of interest, but rather some surrogate endpoint believed to be relevant for predicting the effect of the intervention on the clinical endpoint. The classic example of such a field is clinical HIV treatment research, where a variety of primary endpoints are used to evaluate the efficacy of new antiretroviral drugs or new combinations of existing drugs. The choice of endpoint reflects either the goal of therapy as recommended by treatment guidelines (e.g. rapid virological suppression) or the licensing requirements of official drug approval organizations (e.g. time to loss of virological response [TLOVR]).

PURPOSE

To review the diversity of endpoints used in recent clinical trials in HIV infection and highlight the methodological issues.

METHODS

We identified articles relating to antiretroviral therapy by searching PubMed and through hand searches of relevant conference abstracts. We restricted the search to randomized controlled trials conducted in HIV-infected adults published/presented from January 2005 until March 2008.

RESULTS

We identified 28 trials in antiretroviral-naive patients (i.e. patients who were starting antiretroviral therapy for the first time at the time of randomization) and 23 trials in antiretroviral-experienced patients. Most trials were performed for purposes of drug licensing, but others were focused on strategies of using approved drugs. Most trials (40 of 51) used a composite primary endpoint (TLOVR in 13). Of note, 22 of these 40 studies reported that they had used a purely virological efficacy endpoint, but the primary endpoint was actually a composite one due to the way in which missing data and treatment switches were considered as failures.

LIMITATIONS

Examples are restricted to HIV clinical trials.

CONCLUSIONS

Whilst most current HIV clinical trials use composite primary endpoints, there are substantial differences in the components that make up these endpoints. In HIV and other fields where precise definitions are variable, guidelines for standardization of definition and reporting would greatly improve the ability to compare trial results.

Pure drug and polymer based nanotechnologies for the improved solubility, stability, bioavailability and targeting of anti-HIV drugs

The impact of human immunodeficiency virus (HIV) infection has been devastating with nearly 7400 new infections every day. Although, the advent of highly active antiretroviral therapy (HAART) has made a tremendous contribution in reducing the morbidity and mortality in developed countries, the situation in developing countries is still grim with millions of people being infected by this disease. The new advancements in the field of nanotechnology based drug delivery systems hold promise to improve the situation. These nanoscale systems have been successfully employed in other diseases such as cancer, and therefore, we now have a better understanding of the practicalities and technicalities associated with their clinical development. Nanotechnology based approaches offer some unique opportunities specifically for the improvement of water solubility, stability, bioavailability and targeting of antiretroviral drugs. This review presents discussion on the contribution of pure drug and polymer based nanotechnologies for the delivery anti-HIV drugs.

Cost-effectiveness of tenofovir as first-line antiretroviral therapy in India

BACKGROUND

World Health Organization guidelines for antiretroviral treatment (ART) in resource-limited settings recommend either stavudine or tenofovir as part of initial therapy. We evaluated the clinical outcomes and cost-effectiveness of first-line ART using tenofovir in India, compared with current practice using stavudine or zidovudine.

METHODS

We used a state-transition model of human immunodeficiency virus (HIV) disease to examine strategies using different nucleoside reverse-transcriptase inhibitors, combined with lamivudine and nevirapine, compared with no ART: (1) stavudine, (2) stavudine with substitution by zidovudine after 6 months, (3) zidovudine, and (4) tenofovir. Data were from the Y. R. Gaitonde Centre for AIDS Research and Education in Chennai, India, and published studies. Results. Discounted mean per person survival was 36.9 months (40.2 months undiscounted) with no ART, 115.5 months (145.3) with stavudine-containing ART, 115.7 months (145.6) with stavudine and 6-month zidovudine substitution, 115.8 months (145.6) with zidovudine-containing ART, and 125.8 months (162.0) with initial tenofovir. Discounted lifetime medical costs were $610 with no ART and ranged from $5580 with stavudine-containing ART to $5720 with zidovudine-containing ART. Initial tenofovir had an incremental cost-effectiveness ratio of $670 per year of life saved, compared with no ART, and was more economically efficient than the other regimens.

RESULTS

were most sensitive to variations in the costs of first-line tenofovir, access to additional ART after treatment failure, and quality of life adjustment.

CONCLUSIONS

Using tenofovir as part of first-line ART in India will improve survival, is cost-effective by international standards, and should be considered for initial therapy for HIV-infected patients in India.

Racial and sex disparities in life expectancy losses among HIV-infected persons in the united states: impact of risk behavior, late initiation, and early discontinuation of antiretroviral therapy

BACKGROUND

Most persons with human immunodeficiency virus (HIV) infection in the United States present to care with advanced disease, and many patients discontinue therapy prematurely. We sought to evaluate sex and racial/ethnic disparities in life-years lost as a result of risk behavior, late presentation, and early discontinuation of HIV care, and we compared these survival losses for HIV-infected persons with losses attributable to high-risk behavior and HIV disease itself.

METHODS

With use of a state-transition model of HIV disease, we simulated cohorts of HIV-infected persons and compared them with uninfected individuals who had similar demographic characteristics. We estimated non-HIV-related mortality with use of risk-adjusted standardized mortality ratios, as well as years of life lost because of late presentation and early discontinuation of antiretroviral therapy (ART) for HIV infection. Data from the national HIV Research Network, stratified by sex and race/ethnicity, were used for estimating CD4+ cell counts at ART initiation.

RESULTS

For HIV-uninfected persons in the United States who have risk profiles similar to those of individuals with HIV infection, the projected life expectancy, starting at 33 years of age, was 34.58 years, compared with 42.91 years for the general US population. Those with HIV infection lost an additional 11.92 years of life if they received HIV care concordant with guidelines; late treatment initiation resulted in 2.60 additional years of life lost, whereas premature ART discontinuation led to 0.70 more years of life lost. Losses from late initiation and early discontinuation were greatest for Hispanic individuals (3.90 years).

CONCLUSIONS

The high-risk profile of HIV-infected persons, HIV infection itself, as well as late initiation and early discontinuation of care, all lead to substantial decreases in life expectancy. Survival disparities resulting from late initiation and early discontinuation of therapy are most pronounced for Hispanic HIV-infected men and women. Interventions focused on risk behaviors, as well as on earlier linkage to and better retention in care, will lead to improved survival for HIV-infected persons in the United States.

Clinical management of treatment-experienced, HIV/AIDS patients in the combination antiretroviral therapy era

Despite the success of combination antiretroviral therapy (ART) in improving clinical outcomes, treatment failure remains a significant challenge, particularly for highly treatment-experienced patients. This review evaluates current issues in the management of HIV-infected, treatment-experienced patients. It may provide guidance in selecting active, tolerable drug combinations that promote a reasonable quality of life, full adherence and a durable treatment response. Current treatment guidelines and clinical trial data were reviewed to identify reasons for treatment failure and to summarize therapy options for treatment-experienced and highly treatment-experienced patients. Current treatment options include nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and inhibitors of viral fusion, entry and integration. The use of NRTIs may be limited by resistance and short- and long-term toxicities. Resistance has restricted the NNRTI class with cross-resistance preventing their sequential use. Etravirine, a next-generation NNRTI, however, demonstrates effective virological suppression in patients with baseline NNRTI resistance. Boosted PIs are key components of ART for treatment-experienced patients. The newer boosted PIs tipranavir and darunavir have demonstrated impressive activity in patients with resistance to NRTIs, NNRTIs and PIs, as well as in less treatment-experienced patients for darunavir. The fusion inhibitor enfuvirtide has demonstrated efficacy in heavily treatment-experienced patients, although injection-site reactions can be problematical. The recently approved integrase inhibitor raltegravir has also shown impressive potency and tolerability in highly treatment-experienced patients. Finally, the entry inhibitor maraviroc has also been approved recently, although its use is somewhat limited by the need for HIV tropism testing. The availability of potent next-generation PIs, NNRTIs, integrase and entry-inhibitors may offer improved therapy for treatment-experienced patients, including those with multiresistant virus. These new drugs may reduce HIV immunological and clinical progression and in doing so may also reduce treatment costs.

US cost effectiveness of darunavir/ritonavir 600/100 mg bid in treatment-experienced, HIV-infected adults with evidence of protease inhibitor resistance included in the TITAN Trial

INTRODUCTION

The phase III TITAN trial evaluated the use of darunavir with low-dose ritonavir (DRV/r) 600/100 mg twice daily (bid) compared with lopinavir with low-dose ritonavir (LPV/r) in treatment-experienced, lopinavir-naive patients. This study estimates the cost effectiveness of DRV/r from a US societal perspective when compared with LPV/r in treatment-experienced patients with a profile similar to those TITAN patients who had one or more International AIDS Society - USA (IAS-USA) primary protease inhibitor (PI) resistance-associated mutations (RAMs) at baseline. This population had less advanced HIV disease and a broader range of previous PI exposure/failure (0 - ≥ 2 PIs) at enrollment than those in the darunavir phase IIb POWER trials.

METHODS

An existing Markov model containing six health states defined by CD4 cell count range (>500, 351-500, 201-350, 101-200, 51-100 and 0-50 cells/mm³) and an absorbing state of death was adapted. Baseline demographics, CD4 cell count distribution and antiretroviral drug usage, virological response (at week 24), and immunological response estimates and matching transition probabilities were based on data collected directly from the one or more IAS-USA PI mutation subpopulation during the first 48 weeks of the TITAN trial, as well as from published literature. Patients were assumed to switch to a regimen containing tipranavir plus an optimized background regimen after treatment failure. For each CD4 cell count range or health state, the utility values, HIV and non-HIV-related mortality rates, and non-antiretroviral-related cost of HIV care estimates were derived from published literature. Unit costs were derived from official local sources. A lifetime horizon was taken in the base-case analysis.

RESULTS

The base-case analysis predicted discounted quality-adjusted survival gains of 0.493 quality-adjusted life-years (QALYs) for DRV/r compared with LPV/r, resulting in an incremental cost-effectiveness ratio (ICER) of US$23,057 per QALY gained over a lifetime horizon. Probabilistic sensitivity analysis indicated a 0.754 probability of an ICER below the threshold of US$50,000 per QALY gained. DRV/r remained cost effective over all parameter ranges tested in extensive one-way sensitivity analyses and variability analyses, which examined the impact of input parameter uncertainty and changes in model assumptions and treatment patterns, respectively. Shortening the model time horizon had the largest impact on the ICER, reducing it most notably to US$4919 with a 10-year time horizon.

CONCLUSION

From a US societal perspective and based on an analysis of the patients with primary IAS-USA PI RAMs enrolled in the darunavir phase III TITAN trial, a highly active antiretroviral therapy (HAART) regimen containing DRV/r 600/100 mg bid is estimated to be a cost-effective therapy when compared with a HAART regimen containing LPV/r, for the management of treatment-experienced, PI-resistant, HIV-infected adults with a broad range of previous PI use/failure.

Cost effectiveness of darunavir/ritonavir 600/100 mg bid in treatment-experienced, lopinavir-naive, protease inhibitor-resistant, HIV-infected adults in Belgium, Italy, Sweden and the UK

BACKGROUND

Using data from the phase IIb POWER trials, darunavir boosted with low-dose ritonavir (DRV/r; 600/100 mg twice daily; bid)-based highly active antiretroviral therapy (HAART) was shown to be significantly more efficacious and cost effective than other protease inhibitor (PI)-based therapy in highly treatment-experienced, HIV-1-infected adults. Furthermore, in the phase III TITAN trial (TMC114-C214), DRV/r 600/100 mg bid-based HAART generated a superior 48-week virological response rate compared with standard-of-care lopinavir/ritonavir (LPV/r; 400/100 mg bid)-based therapy in treatment-experienced, lopinavir-naive patients, and in particular those with one or more International AIDS Society - USA (IAS-USA) primary PI resistance-associated mutations at baseline. These patients had a broader degree of previous PI use/failure (0 - ≥ 2) than the POWER patients.

OBJECTIVES

To determine whether DRV/r 600/100 mg bid-based HAART is cost effective compared with LPV/r-based therapy, from the perspective of Belgian, Italian, Swedish and UK reimbursement authorities, when used in treatment-experienced patients similar to TITAN patients with one or more IAS-USA primary PI mutations at baseline.

METHODS

An existing Markov model containing health states defined by CD4 cell count ranges (>500, 351-500, 201-350, 101-200, 51-100 and 0-50 cells/mm³) and an absorbing state of death was adapted for use in the above-mentioned healthcare settings. Baseline demographics, CD4 cell count distribution, antiretroviral drug usage, virological/immunological response rates and matching transition probabilities were based on data collected during the first 48 weeks of therapy in the modelled subgroup of TITAN patients and the published literature. After treatment failure, patients were assumed to switch to a follow-on combination regimen. For each health state, utility values and mortality rates were obtained from the published literature. Data from local observational studies (Belgium, Sweden and Italy) or the published literature (UK) were used to determine resource-use patterns and costs associated with each CD4 cell count range. Unit costs were derived from official local sources; a lifetime horizon was taken and discount rates were chosen based on local guidelines.

RESULTS

The base-case analysis predicted quality-adjusted life year (QALY) gains of 0.785 in Belgium, 0.608 in Italy, 0.584 in Sweden and 0.550 in the UK when DRV/r-based therapy was used instead of LPV/r-based treatment. The estimated base-case incremental cost-effectiveness ratios (ICERs) were €6964/QALY gained in Belgium, €9277/QALY gained in Italy, €6868 (SEK69,687)/QALY gained in Sweden and €14,778 (£12 612)/QALY gained in the UK. Assuming a threshold of €30,000/QALY gained, DRV/r-based therapy remained cost effective over most parameter ranges tested in extensive one-way sensitivity analyses. The variation of immunological response rates and the time horizon were identified as important drivers of cost effectiveness. Probabilistic sensitivity analysis revealed a greater than 70% probability of achieving an ICER below this threshold in all four healthcare settings.

CONCLUSION

From the perspective of Belgian, Italian, Swedish and UK payers, DRV/r 600/100 mg bid-based HAART is predicted to be cost effective compared with LPV/r 400/100 mg bid-based therapy, when used to manage treatment experienced, lopinavir-naive, PI-resistant, HIV-infected adults with a broad range of previous PI use/failure.

Formulation preference, tolerability and quality of life assessment following a switch from lopinavir/ritonavir soft gel capsule to tablet in human immunodeficiency virus-infected patients

BACKGROUND

Lopinavir/ritonavir (LPV/r) tablet compared to the soft gel capsule (SGC) formulation has no oleic acid or sorbitol, has no refrigeration or food-restriction requirements, and has less pharmacokinetic variability. We compared the tolerability, quality of life (QoL), and formulation preference after switching from LPV/r SGC to the tablet formulation.

METHODS

In a prospective, single-arm, cohort study-design, 74 human immunodeficiency virus (HIV) infected subjects stable on LPV/r-based therapy were enrolled prior to (n = 25) or 8 weeks (n = 49) after switching from SGC to tablet. Baseline data included clinical laboratory tests, bowel habit survey (BHS) and QoL questionnaire (recalled if enrolled post-switch). Global Condition Improvement (GCI)-score, BHS-score, QoL-score, and formulation preference data were captured at weeks 4 and 12.

RESULTS

At week 12 post-enrollment; the tablet was preferred to the SGC (74% vs. 10%, p < 0.0001). GCI-overall-tolerability score was 2.46 +/- 3.30 on a scale of -7 to +7, with 90% admitting to feeling better or about the same. Stool frequency, consistency, volume, and +/- blood improved, however the improvement was significant in "consistency" only (p = 0.03). Aggregate Bowel Habit-Profile improved (BHS-score change = -0.227, p = 0.01). Inverse relationship existed between GCI and BHS (slope = -1.2, p = 0.02) at week-4, suggesting that improved overall-tolerability was related to better gastrointestinal (GI)-tolerance. QoL-scores were stable. Mean reductions in total cholesterol of 9.20 mg/dL (p = 0.02), in triglycerides of 33 mg/dL (p = 0.04), and in HDL of 4.50 mg/dL (p = 0.01) unrelated to lipid-lowering therapy, were observed at week 12.

CONCLUSIONS

LPV/r-tablet was well tolerated and preferred to the SGC in HIV infected subjects, with stable QoL and appreciable improvement in GI-tolerability. The unexpected changes in lipid profile deserve further evaluation.

Antiretroviral therapy-induced liver alterations

PURPOSE OF REVIEW

Antiretroviral drugs are associated with hepatotoxicity. Progress in our knowledge on the prevalence, contributory factors and mechanisms is reviewed.

RECENT FINDINGS

Liver toxicity is highly prevalent and a major cause of hospitalization among HIV-infected individuals. Liver steatosis is probably more frequent in the setting of hepatitis C virus coinfection but is also seen in noncoinfected patients. Among the individual drugs, severe liver toxicity is more strongly associated with nevirapine, and the mitochondrial toxicity of some nucleoside analogues. Mitochondrial toxicity can also induce or contribute to steatohepatitis, with dietary uridine supplementation as a possible strategy of prevention. Atazanavir inhibits UDP-glucuronosyltransferase, which in Gilberts' syndrome has been associated with breast cancer. A UDP-glucuronosyltransferase gene promoter variant predisposes to hyperbilirubinemia. Tipranavir induces elevated transaminases more frequently than boosted comparator protease inhibitors. CCR5 inhibitors may predispose to hepatotoxic events by causing an imbalance in the cytokine response.

SUMMARY

Hepatotoxicity is associated with all classes of antiretroviral agents and continues to contribute to hospitalization.

Atazanavir: a review of its use in the management of HIV-1 infection

Atazanavir (Reyataz), a protease inhibitor (PI), is approved in many countries for use as a component of antiretroviral therapy (ART) regimens for the treatment of adult, and in some countries in paediatric, patients with HIV-1 infection. ART regimens containing ritonavir-boosted atazanavir improved virological and immunological markers in adult patients with HIV-1 infection, and had similar efficacy to regimens containing lopinavir/ritonavir in treatment-naive and treatment-experienced patients. In addition, unboosted atazanavir was noninferior to ritonavir-boosted atazanavir in treatment-naive patients. Atazanavir is administered once daily and has a low capsule burden. Atazanavir, whether unboosted or boosted, was generally well tolerated and appeared to be associated with less marked metabolic effects, including less alteration of lipid levels, than other PIs. These properties mean that boosted atazanavir, and unboosted atazanavir in patients unable to tolerate ritonavir, continues to have a role as a component of ART regimens in patients with HIV-1 infection.

HIV protease inhibitors: recent clinical trials and recommendations on use

BACKGROUND

HIV protease inhibitors (PIs) are potent antiretroviral drugs that represent a pivotal component of highly active antiretroviral therapy (HAART). PIs have evolved over the years to gain in potency, convenience, tolerability and genetic barrier to resistance.

OBJECTIVE

Updated summary of evidence-based information about the efficacy and safety of PIs on initial, simplification and rescue interventions in HIV patients.

METHODS

Review of available data reported in peer-reviewed journals, medical conferences and treatment guidelines.

RESULTS

Due to their characteristics, PIs are, and will remain, a cornerstone component in most lines of antiretroviral therapy. The antiviral activity, tolerability and convenience of PIs have improved significantly in recent years. Differences between compounds within this class may favour their use in specific situations, such as the friendly metabolic profile of atazanavir in patients with cardiovascular disease or the high genetic barrier of darunavir or tipranavir in heavily pretreated individuals with HIV.

Improving outcomes in state AIDS drug assistance programs

BACKGROUND

State AIDS Drug Assistance Programs (ADAPs) provide antiretroviral medications to patients with no access to medications. Resource constraints limit the ability of many ADAPs to meet demand for services.

OBJECTIVE

To determine ADAP eligibility criteria that minimize morbidity and mortality and contain costs.

METHODS

We used Discrete Event Simulation to model the progression of HIV-infected patients and track the utilization of an ADAP. Outcomes included 5-year mortality and incidence of first opportunistic infection or death and time to starting antiretroviral therapy (ART). We compared expected outcomes for 2 policies: (1) first-come first-served (FCFS) eligibility for all with CD4 count

RESULTS

In the base case, prioritizing patients with CD4 counts

CONCLUSION

When resources are limited, programs that provide ART can improve outcomes by prioritizing patients with low CD4 counts.

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Key Words

• aids
• anti-hiv agents*/therapeutic use
• adap
• government programs
• resource allocation*
• cd4 lymphocyte count

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MESH Headings

• Acquired Immunodeficiency Syndrome/drug therapy
• Acquired Immunodeficiency Syndrome/economics
• Acquired Immunodeficiency Syndrome/immunology
• Adult
• Anti-HIV Agents/economics
• Anti-HIV Agents/therapeutic use
• CD4 Lymphocyte Count
• Female
• Humans
• Male
• Middle Aged
• Models, Statistical
• Outcome Assessment, Health Care
• Public Assistance
• Resource Allocation
• State Health Plans
• Time Factors
• United States

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Grants

• K24AI062476 NIAID NIH HHS
• R37 AI042006 NIAID NIH HHS
• R01 MH073445 NIMH NIH HHS
• R37AI42006 NIAID NIH HHS
• R01MH073445 NIMH NIH HHS
• K24 AI062476 NIAID NIH HHS
• K01AI073193 NIAID NIH HHS
• P30 AI060354 NIAID NIH HHS
• P30AI060354 NIAID NIH HHS
• K01 AI073193 NIAID NIH HHS

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Affiliation(s)

Benjamin P Linas Divisions of General Medicine, Massachusetts General Hospital, Boston, MA 02115, USA.
Elena Losina
Annette Rockwell
Rochelle P Walensky
Kevin Cranston
Kenneth A Freedberg

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Collaborators Collapse

Antiretroviral treatment of HIV infection: Swedish recommendations 2007

On 3 previous occasions, in 2002, 2003 and 2005, the Swedish Medical Products Agency (Läkemedelsverket) and the Swedish Reference Group for Antiviral Therapy (RAV) have jointly published recommendations for the treatment of HIV infection. An expert group, under the guidance of RAV, has now revised the text again. Since the publication of the previous treatment recommendations, 1 new drug for the treatment of HIV has been approved - the protease inhibitor (PI) darunavir (Prezista). Furthermore, 3 new drugs have become available: the integrase inhibitor raltegravir (MK-0518), the CCR5-inhibitor maraviroc (Celsentri), both of which have novel mechanisms of action, and the non-nucleoside reverse transcriptase inhibitor (NNRTI) etravirine (TMC-125). The new guidelines differ from the previous ones in several respects. The most important of these are that abacavir is now preferred to tenofovir and zidovudine, as a first line drug in treatment-naïve patients, and that initiation of antiretroviral treatment is now recommended before the CD4 cell count falls below 250/microl, rather than 200/microl. Furthermore, recommendations on the treatment of HIV infection in children have been added to the document. As in the case of the previous publication, recommendations are evidence-graded in accordance with the Oxford Centre for Evidence Based Medicine, 2001 (see http://www.cebm.net/levels_of_evidence.asp#levels).

Identification of new genotypic cut-off levels to predict the efficacy of lopinavir/ritonavir and darunavir/ritonavir in the TITAN trial

BACKGROUND

Genotypic algorithms used to predict the clinical efficacy of lopinavir/ritonavir (LPV/r) have included a range of mutation lists and efficacy endpoints. Normally, HIV clinical trials are powered to detect a difference between treatment arms of 10-12% for the endpoint of viral load suppression <50 HIV-1 RNA copies/mL. The TITAN trial evaluated LPV/r vs. darunavir/ritonavir (DRV/r) in treatment-experienced patients with viral load >1000 copies/mL. This analysis aimed to re-evaluate resistance algorithms for LPV/r in the TITAN trial.

METHODS

Baseline genotype data were classified using seven genotypic resistance algorithms: International AIDS Society USA (IAS-USA) LPV mutations (current cut-off=6), Abbott 2007 mutation list (cut-off=3), ANRS mutations (cut-off=4), FDA mutations (cut-off=3), Stanford, REGA and IAS-USA major protease inhibitor (PI) mutations. Efficacy in the TITAN trial (HIV-1 RNA <50 copies/mL at week 48) was correlated with the number of mutations from each list, to show the 'efficacy advantage cut-off level': the number of mutations from each list associated with a difference in efficacy between treatment arms of at least 12%.

RESULTS

Multivariate logistic regression analysis identified lower genotypic cut-off levels than previously reported where there was at least 12% lower efficacy for LPV/r vs. DRV/r. These efficacy advantage cut-off levels were: IAS-USA LPV mutations, cut-off=3; Abbott 2007, cut-off=2; ANRS LPV, cut-off=3; FDA LPV mutations, cut-off=2; major IAS-USA PI mutations, cut-off=1; Stanford algorithm, cut-off=low-level LPV resistance; REGA algorithm, cut-off=intermediate-level LPV resistance. There were linear falls in HIV-1 RNA suppression rates with rising mutation counts in the TITAN, French LPV ATU, BMS-045 and RESIST trials.

CONCLUSIONS

The analysis identified more sensitive cut-off levels for LPV genotypic algorithms, below those currently used.

[Interpreting methodological and statistical considerations in studies of rescue therapy]

The methodology used in studies of rescue therapy is sometimes complex. This is because of the heterogeneity of objectives and options. Firstly, the definition of failure has multiple interpretations and subtle distinctions. Secondly, the aim of treatment in these patients has varied according to the available treatment options in each case and at each moment of time. Lastly, the methodology used to develop these studies of rescue therapy has varied over time in line with changes in their aims and options. Currently, a new change can be expected to adjust to the current situation, since the number of therapeutic options for rescue therapy has substantially increased in the last year. The present review discusses changes in the design of these studies, the main methodological issues to be taken into account and the recommendations on this subject.

Hyperbilirubinemia during atazanavir treatment in 2,404 patients in the Italian atazanavir expanded access program and MASTER Cohorts

BACKGROUND

Although the mechanism of atazanavir (ATV)-related hyperbilirubinemia is well identified, its prevalence, risk factors, and association with transaminase flares have rarely been assessed in a large population from the "real life" setting.

METHODS

Prospectively collected data on 2,404 patients from the Italian MASTER Cohort and the Italian ATV expanded access program database were examined. Uni- and multivariable Cox proportional hazards regression models were conducted to identify risk factors for grade >or= III hyperbilirubinemia during the administration of ATV. The risk of increased levels of serum alanine aminotransferase (ALT) was compared between patients with or without grade >or= III hyperbilirubinemia in a Cox regression analysis stratified by hepatitis C virus (HCV) serostatus.

RESULTS

Grade III and IV hyperbilirubinemia were observed in 1,072 (44.6%) and 174 (7.2%) of the patients, respectively. Higher CD4+ T-cell counts, abnormal bilirubinemia at baseline, and ritonavir co-administration were associated with a higher risk of developing grade >or= III hyperbilirubinemia. In contrast, female gender, clinical class C, and non-nucleoside reverse transcriptase co-administration appeared to be protective. Higher bilirubinemia at baseline and the use of ritonavir were associated with a higher risk of grade IV hyperbilirubinemia. The occurrence of grade >or= III hyperbilirubinemia was not associated with severe hepatotoxicity (hazard ratio 1.00, 95% confidence interval 0.64-1.57; p = 0.997).

CONCLUSIONS

Hyperbilirubinemia is a common side effect of an ATV pharmacotherapeutic regimen. However, grade IV increase in bilirubin was rarely found. In most cases, ATV hyperbilirubinemia appeared to be an innocent phenomenon as far as the risk of a subsequent increase in liver enzyme level is concerned.

Improvement in lipid profiles over 6 years of follow-up in adults with AIDS and immune reconstitution

OBJECTIVES

The aim of the study was to evaluate long-term changes in lipids and to assess other coronary heart disease (CHD) risk factors in highly experienced AIDS patients with immune reconstitution, and to examine their association with antiretroviral therapy (ART).

METHODS

We evaluated 433 AIDS patients with prior severe immunosuppression and ART-based immune reconstitution, followed in a multicentre prospective observational study between 2000 and 2006. We estimated the prevalence at entry of hypercholesterolaemia and metabolic syndrome, and 10-year CHD risks. Trends in total cholesterol (TC), triglycerides (TG) and high-density lipoprotein (HDL) cholesterol were evaluated over time, and use of specific ART drugs at each study visit was assessed using mixed effect models, adjusting for CHD risk factors and use of lipid-lowering agents.

RESULTS

At entry to observational follow-up, 28% of the 433 subjects had hypercholesterolaemia and 15% had a predicted 10-year CHD risk above 20%. Average TC and fasting TG levels declined over the follow-up period (median=5.8 years), and these declines were associated with increased use of physician-prescribed lipid-lowering agents and changes in ART regimens. After adjustment for CHD risk factors, TC and TG levels were significantly higher for those on ritonavir-boosted protease inhibitors and those on nonnucleoside reverse transcriptase inhibitors (NNRTIs), particularly efavirenz, than for other patients.

CONCLUSIONS

Abnormalities in serum lipids were common at baseline but became less so over time, and this improvement was associated with increased use of lipid-lowering agents and selection of ART agents with less deleterious effects on lipids.

HIV preexposure prophylaxis in the United States: impact on lifetime infection risk, clinical outcomes, and cost-effectiveness

BACKGROUND

The combination of tenofovir and emtricitabine shows promise as HIV preexposure prophylaxis (PrEP). We sought to forecast clinical, epidemiologic, and economic outcomes of PrEP, taking into account uncertainties regarding efficacy, the risks of developing drug resistance and toxicity, behavioral disinhibition, and drug costs.

METHODS

We adapted a computer simulation of HIV acquisition, detection, and care to model PrEP among men who have sex with men and are at high risk of HIV infection (i.e., 1.6% mean annual incidence of HIV infection) in the United States. Base-case assumptions included 50% PrEP efficacy and monthly tenofovir-emtricitabine costs of $753. We used sensitivity analyses to examine the stability of results and to identify critical input parameters.

RESULTS

In a cohort with a mean age of 34 years, PrEP reduced lifetime HIV infection risk from 44% to 25% and increased mean life expectancy from 39.9 to 40.7 years (21.7 to 22.2 discounted quality-adjusted life-years). Discounted mean lifetime treatment costs increased from $81,100 to $232,700 per person, indicating an incremental cost-effectiveness ratio of $298,000 per quality-adjusted life-year gained. Markedly larger reductions in lifetime infection risk (from 44% to 6%) were observed with the assumption of greater (90%) PrEP efficacy. More-favorable incremental cost-effectiveness ratios were obtained by targeting younger populations with a higher incidence of infection and by improvements in the efficacy and cost of PrEP.

CONCLUSIONS

PrEP could substantially reduce the incidence of HIV transmission in populations at high risk of HIV infection in the United States. Although it is unlikely to confer sufficient benefits to justify the current costs of tenofovir-emtricitabine, price reductions and/or increases in efficacy could make PrEP a cost-effective option in younger populations or populations at higher risk of infection. Given recent disappointments in HIV infection prevention and vaccine development, additional study of PrEP-based HIV prevention is warranted.

Hepatotoxicity and gastrointestinal intolerance when healthy volunteers taking rifampin add twice-daily atazanavir and ritonavir

BACKGROUND

Rifampin is the cornerstone of antituberculosis therapy, but induction of hepatic cytochrome P4503A by rifampin markedly lowers HIV protease inhibitor plasma concentrations.

METHODS

This phase 1, open-label, one-arm study was designed to assess pharmacokinetic interactions and safety of atazanavir, ritonavir, and rifampin among 14 evaluable HIV-seronegative volunteers. The study included 3 sequential periods of study drug dosing, with plasma sampling for pharmacokinetic analyses to occur on the last day of each period. During period 1, participants received rifampin 600 mg every 24 hours for 8 days. During period 2, participants continued rifampin 600 mg every 24 hours, and added atazanavir 300 mg and ritonavir 100 mg every 12 hours, to continue for at least 11 days. During period 3, atazanavir was to be increased to 400 mg every 12 hours.

RESULTS

Upon adding atazanavir and ritonavir, the first 3 subjects developed vomiting and transaminase elevations resulting in study drug discontinuation. The study was therefore terminated.

CONCLUSIONS

Coadministration of rifampin with HIV protease inhibitors may not be a viable treatment option if rifampin administration precedes protease inhibitor initiation. Future studies, which explore concomitant HIV protease inhibitors with rifampin must carefully consider the sequence in which drugs are initiated.

Psychosocial issues influencing treatment adherence in patients on multidrug rescue therapy: perspectives from patients and their health care providers

Multi-drug rescue therapy (MDRT) is often used for the treatment of highly experienced patients who harbor HIV variants with decreased susceptibility to multiple antiretrovirals. Patients on MDRT typically have limited treatment options, and without treatment, their prognosis can be poor. Yet the decision to go on MDRT is not always straightforward as MDRT can be associated with significant challenges including multiple daily doses, higher pill burden, emerging toxicities, and drug interactions. All of these may compromise adherence, which is often a major reason why patients may need MDRT in the first place. Little is known about how patients and health care providers (HCPs) experience MDRT. This study sought to explore areas of convergence and divergence between patients and HCPs in order to identify gaps in treatment and factors that may impact adherence to MDRT. A qualitative interview method based on grounded theory was used. Twelve patients and seven HCPs completed a 60-minute semistructured interview. Patients were asked about challenges, facilitative aspects of staying on MDRT, the decision to initiate treatment, their role, and the role of HCPs in their health care. HCPs were asked about their experience working with MDRT patients, their role, and the role of the patient. Congruent themes emerged from the two groups: developing a working relationship, treatment factors, information requirements, and readiness for treatment. There were no discrepancies in role perspectives. Patients and HCPs agreed on the need to optimize patients' readiness, willingness, and ability to embark on MDRT to maximize adherence. HCPs assumptions about beginning MDRT based solely on medical indications must be checked and discussed to ensure patients' motivation. In conclusion, adherence to MDRT demands a substantial behavior change, recognized as a major challenge by patients. Allocating the time to make a commitment to treatment can optimize adherence. It is therefore crucial that patients be provided with time to make informed decisions, explore and resolve their willingness and readiness to commit to treatment, and maintain supportive relationships with their HCPs, all of which can optimize adherence to MDRT.