Risk of early virological failure of once-daily tenofovir-emtricitabine plus twice-daily nevirapine in antiretroviral therapy-naive HIV-infected patients

Increasing HIV-1 Drug Resistance Between 2010 and 2012 in Adults Participating in Population-Based HIV Surveillance in Rural KwaZulu-Natal, South Africa

As more human immunodeficiency virus (HIV)–infected patients access combination antiretroviral therapy (cART), higher proportions of newly infected patients may be infected with drug-resistant viruses. Regular surveillance of transmitted drug resistance (TDR) is required in southern Africa where high rates of transmission persist despite rapid expansion of ART. Dried blood spot samples from cART-naive participants from two rounds of an annual population-based HIV surveillance program in rural KwaZulu-Natal were tested for HIV RNA, and samples with HIV RNA >10,000 copies/ml were genotyped for drug resistance. The 2009 surveillance of drug resistance mutation (SDRM) list was used for drug resistance interpretation. The data were added to previously published data from the same program, and the χ² test for trend was used to test for trend in estimated prevalence of any TDR. Seven hundred and one participants' data were analyzed: 67 (2010), 381 (2011), and 253 (2012). No TDR was detected in 2010. Years 2011 and 2012 had 18 participants with SDRMs 4.7% and 7.1%, respectively (p = .02, χ² test for trend). The nonnucleoside reverse transcriptase inhibitor mutation, K103N, was the most common mutation, occurring in 27 (3.8%) of the participants, while nucleoside reverse transcriptase inhibitor (NRTI) SDRMs were detected in 10 (1.4%) of the participants, of whom eight had only a single NRTI SDRM. The increase in levels of drug resistance observed in this population could be a signal of increasing transmission of drug-resistant HIV. Thus, continued surveillance is critical to inform public health policies around HIV treatment and prevention.

Superior Effectiveness of Zidovudine Compared With Tenofovir When Combined With Nevirapine-based Antiretroviral Therapy in a Large Nigerian Cohort

BACKGROUND

Despite sparse efficacy data, tenofovir-emtricitabine or tenofovir-lamivudine plus nevirapine is used in many resource-constrained settings.

METHODS

This retrospective cohort study included patients initiating nevirapine-based antiretroviral therapy (ART) with either tenofovir-emtricitabine or lamivudine (tenofovir group) or zidovudine-lamivudine (zidovudine group). Clinical, virologic, and immunologic evaluations were performed at baseline and every 6 months. Virologic failure was defined as 2 consecutive human immunodeficiency virus (HIV)-RNA values >1000 copies/mL. Patients were included from ART initiation until time of failure, regimen switch, discontinuation, or last HIV-RNA measurement. Cox proportional hazards regression was used to model factors influencing time to failure. Bias due to dependent censoring was investigated via inverse probability weighted pooled logistic regression.

RESULTS

A total of 5547 patients were evaluated; 1484 (26.8%) were in the tenofovir group and 4063 (73.2%) were in the zidovudine group. In the adjusted model, tenofovir regimen (hazard ratio [HR], 1.47; 95% confidence interval [CI], 1.21-1.79) and higher baseline log10 HIV-RNA (HR, 1.15; 95% CI, 1.03-1.28) were associated with virologic failure. Higher baseline log10 CD4+ cell count (HR, 0.50; 95% CI, .40-.63) and increasing age (HR, 0.98; 95% CI, .97-.99) decreased the risk of virologic failure. Inverse probability weighting results were consistent with the primary analysis.

CONCLUSIONS

Compared with zidovudine-lamivudine, the use of tenofovir-lamivudine or emtricitabine in combination with nevirapine was a strong predictor of virologic failure in our cohort, which was not explained by other risk factors or criteria for regimen selection.

Nevirapine-based regimens in HIV-infected antiretroviral-naive patients: systematic review and meta-analysis of randomized controlled trials

Background

Nevirapine belongs to the group of non-nucleoside reverse transcriptase inhibitors (NNRTIs) and is commonly administered in first-line treatment of HIV infection.

Objective

Systematic review and meta-analysis was undertaken to compare effectiveness of nevirapine-based regimens with other antiretroviral schedules used as an initial treatment of HIV-infected antiretroviral-naive subjects.

Methods

Electronic databases (PubMed, EMBASE, the Cochrane Library, Trip Database) were searched up to 28 December 2012 for randomized controlled trials (RCTs) published as a full text and regarding nevirapine-based regimens used as a initial treatment for HIV infection. Meta-analysis was performed with RevMan^® V 5.2 software.

Results

Twelve RCTs were included in the systematic review and all of them were suitable for meta-analysis. Results of the meta-analysis have shown that nevirapine, efavirenz, and ritonavir-boosted protease inhibitor, added to the background regimens, were equally effective in terms of reaching undetectable plasma HIV RNA level as well as risk of disease progression or death. Compared with ritonavir-boosted protease inhibitor-based regimens, nevirapine-based regimens statistically significantly increased the risk of discontinuation of assigned treatment (RR=3.10; 95% CI: 1.14-8.41; p<0.05).

Conclusions

Despite limited RCTs data available for particular comparisons, our results suggest that nevirapine-based regimens may be considered for first-line treatment of HIV-infected adults, due to their comparable efficacy to the other currently recommended initial antiretroviral therapies.

The impact of choice of NNRTI on short-term treatment outcomes among HIV-infected patients prescribed tenofovir and lamivudine in Johannesburg, South Africa

Introduction

Recent WHO guidelines for resource-limited settings recommend tenofovir in first-line antiretroviral therapy (ART) yet there are suggestions that patients receiving nevirapine with tenofovir have worse outcomes than those receiving efavirenz. We sought to compare outcomes among those taking nevirapine vs. efavirenz with tenofovir and lamivudine.

Methods

We analyzed data on ART naïve, non-pregnant patients, ≥18 years old without tuberculosis co-infection, initiating tenofovir with lamivudine and either nevirapine or efavirenz between April 1, 2010 and July 31, 2011 (when South Africa’s public-sector use of tenofovir began) at Themba Lethu Clinic in South Africa. We measured virologic suppression (viral load <400 copies/ml), virologic failure (2 consecutive viral loads >1000 copies/ml), and attrition (death/loss to follow-up) all at 12 months after ART initiation. Modified Poisson regression with robust error estimation was used to estimate risk ratios (RR) and 95% confidence intervals (CI) for predictors of each outcome.

Results

2,254 patients were prescribed efavirenz, 131 nevirapine. Patients were followed a median (range) of 12.0 (0.1–12.0) person-months. 62.2% were female and median (IQR) age was 37.7 years (31.5–44.1). Patients prescribed efavirenz had similar initiating CD4 counts (median 132 for both regimens) but were somewhat more likely to be WHO Stage III or IV (39.6% vs. 33.6%) than those prescribed nevirapine. No difference in attrition was found (aRR: 0.83; 95% CI: 0.49–1.41). Among patients with ≥1 viral load within 1 year on ART, those prescribed nevirapine were as likely to reach virologic suppression (aRR: 0.97; 95% CI: 0.88–1.07) but more likely to experience virologic failure (aRR: 1.84; 95% CI: 1.02–3.31) than those prescribed efavirenz.

Conclusions

Our results support the notion that, among patients prescribed tenofovir and lamivudine, virologic failure is more common among those taking nevirapine than among those taking efavirenz. Longer-term follow up and larger studies will be needed to confirm this finding.

A 72-week randomized study of the safety and efficacy of a stavudine to zidovudine switch at 24 weeks compared to zidovudine or tenofovir disoproxil fumarate when given with lamivudine and nevirapine

BACKGROUND

Due to superior long-term toxicity profiles, zidovudine (AZT) and tenofovir disoproxil fumarate (TDF) are preferred over stavudine (d4T) for first-line antiretroviral regimens. However, short-term d4T use could be beneficial in avoiding AZT-induced anaemia.

METHODS

We randomized (1:1:1) 150 treatment-naive Thai HIV-infected adults with CD4(+) T-cell count <350 cells/mm(3) to arm 1 (24-week GPO-VIR S30(®) [d4T plus lamivudine (3TC) plus nevirapine (NVP)] followed by 48-week GPO-VIR Z250(®) [AZT plus 3TC plus NVP]), arm 2 (72-week GPO-VIR Z250(®)) or arm 3 (72-week TDF plus emtricitabine [FTC] plus NVP). Haemoglobin (Hb), dual energy x-ray absorptiometry, neuropathic signs, estimated glomerular filtration rate (eGFR), CD4(+) T-cell count, plasma HIV RNA and adherence were assessed.

RESULTS

In an intention-to-treat analysis, mean Hb decreased from baseline to week 24 in arm 2 compared with arm 1 (-0.19 versus 0.68 g/dl; P=0.001) and arm 3 (0.48 g/dl; P=0.010). Neuropathic signs were more common in arm 2 compared with arm 3 (20.4 versus 4.2%; P=0.028) at week 24. There were no differences in changes in peripheral fat and eGFR from baseline to weeks 24 and 72 among arms. CD4(+) T-cell count increased more in arm 1 than arms 2 and 3 from baseline to week 24 (168 versus 117 and 118 cells/mm(3); P=0.01 and 0.02, respectively) but the increase from baseline to week 72 was similar among arms.

CONCLUSIONS

A 24-week d4T lead-in therapy caused less anaemia and greater initial CD4(+) T-cell count increase than initiating treatment with AZT. This strategy could be considered in patients with baseline anaemia or low CD4(+) T-cell count. If confirmed in a larger study, this may guide global recommendations on antiretroviral initiation where AZT is more commonly used than TDF.

A review of the virological efficacy of the 4 World Health Organization-recommended tenofovir-containing regimens for initial HIV therapy

We systematically reviewed studies of the virological efficacy of the 4 new tenofovir (TDF)-containing regimens recommended for initial antiretroviral (ARV) therapy in the 2010 World Health Organization ARV Treatment Guidelines. Thirty-three studies assessed the efficacy of 1 or more TDF-containing regimens: TDF/lamivudine (3TC)/nevirapine (NVP) (n = 3), TDF/ emtricitabine (FTC)/NVP (n = 9), TDF/3TC/efavirenz (EFV) (n = 6), and TDF/FTC/EFV (n = 19). TDF/3TC/NVP was the least well-studied and appeared the least efficacious of the 4 regimens. In 2 comparative studies, TDF/3TC/NVP was associated with significantly more virological failure than AZT/3TC/NVP; a third study was terminated prematurely because of early virological failure. TDF/FTC/NVP was either equivalent or inferior to its comparator arms. TDF/3TC/EFV was equivalent to its comparator arms. TDF/FTC/EFV was equivalent or superior to its comparator arms. Possible explanations for these findings include the greater antiviral activity of EFV versus NVP and longer intracellular half-life of FTC-triphosphate versus 3TC-triphosphate. Further study of TDF/3TC/NVP is required before it is widely deployed for initial ARV therapy.

Evaluation of the safety and effectiveness of nevirapine plus coformulated tenofovir/emtricitabine as first-line therapy in routine clinical practice

Despite having demonstrated noninferior efficacy against atazanavir/ritonavir plus coformulated tenofovir/emtricitabine (cTDF/FTC), the combination of nevirapine plus cTDF/FTC is not included among preferred regimens in some international guidelines. This combination is frequently used in Spain. We analyzed its effectiveness and safety as first-line therapy in a routine clinical practice. A retrospective, multicenter study was performed in treatment-naive HIV-1-infected subjects who started nevirapine plus cTDF/FTC as first-line therapy according to the nevirapine CD4(+) cell count threshold. The primary endpoint was the proportion of subjects with plasma HIV-1 RNA <50 copies/ml at week 48. We included 123 subjects starting the regimen from 2005 to 2008. The median age was 41.0 years, the median baseline CD4(+) cell count was 215 cells/μl, the median plasma viral load (VL) was 4.83 log(10) copies/ml, and 22% had hepatitis C coinfection. At week 48, 96 subjects (78%; 95% CI: 69.9-84.4) had a VL <50 copies/ml in an ITT analysis, and the median rise in the CD4(+) cell count was 118 cells/μl. Virological failure was observed in 6.5% (8/123) of subjects, all them before week 24 and related to poor adherence. There was no relationship between virological failure and baseline CD4(+) cell count or VL. Ten percent (13/123) of the subjects discontinued the treatment due to adverse events. There was a significant decrease in total/HDL-cholesterol ratio (p=0.03) with an increase in HDL-cholesterol (p=0.01) over 48 weeks. The combination of nevirapine plus cTDF/FTC showed a high virological efficacy without unexpected toxicities as a first-line treatment in a routine clinical practice.

Comparative outcomes of tenofovir-based and zidovudine-based antiretroviral therapy regimens in Lusaka, Zambia

BACKGROUND

Although tenofovir (TDF) is a common component of antiretroviral therapy (ART), recent evidence suggests inferior outcomes when it is combined with nevirapine (NVP).

METHODS

We compared outcomes among patients initiating TDF + emtricitabine or lamivudine (XTC) + NVP, TDF + XTC + efavirenz (EFV), zidovudine (ZDV) + lamuvidine (3TC) + NVP, and ZDV + 3TC + EFV. We categorized drug exposure by initial ART dispensation by a time-varying analysis that accounted for drug substitutions and by predominant exposure (>75% of drug dispensations) during an initial window period. Risks for death and program failure were estimated using Cox proportional hazard models. All regimens were compared with ZDV + 3TC + NVP.

RESULTS

Between July 2007 and November 2010, 18,866 treatment-naive adults initiated ART: 18.2% on ZDV + 3TC + NVP, 1.8% on ZDV + 3TC + EFV, 36.2% on TDF + XTC + NVP, and 43.8% on TDF + XTC + EFV. When exposure was categorized by initial prescription, patients on TDF + XTC + NVP [adjusted hazard ratio (AHR): 1.45; 95% confidence interval (CI): 1.03 to 2.06] had a higher post-90-day mortality. TDF + XTC + NVP was also associated with an elevated risk for mortality when exposure was categorized as time-varying (AHR: 1.51; 95% CI: 1.18 to 1.95) or by predominant exposure over the first 90 days (AHR: 1.91, 95% CI: 1.09 to 3.34). However, these findings were not consistently observed across sensitivity analyses or when program failure was used as a secondary outcome.

CONCLUSION

TDF + XTC + NVP was associated with higher mortality when compared with ZDV + 3TC + NVP but not consistently across sensitivity analyses. These findings may be explained in part by inherent limitations to our retrospective approach, including residual confounding. Further research is urgently needed to compare the effectiveness of ART regimens in use in resource-constrained settings.

Nevirapine- versus lopinavir/ritonavir-based initial therapy for HIV-1 infection among women in Africa: a randomized trial

BACKGROUND

Nevirapine (NVP) is widely used in antiretroviral treatment (ART) of HIV-1 globally. The primary objective of the AA5208/OCTANE trial was to compare the efficacy of NVP-based versus lopinavir/ritonavir (LPV/r)-based initial ART.

METHODS AND FINDINGS

In seven African countries (Botswana, Kenya, Malawi, South Africa, Uganda, Zambia, and Zimbabwe), 500 antiretroviral-naïve HIV-infected women with CD4<200 cells/mm(3) were enrolled into a two-arm randomized trial to initiate open-label ART with tenofovir (TDF)/emtricitabine (FTC) once/day plus either NVP (n = 249) or LPV/r (n = 251) twice/day, and followed for ≥48 weeks. The primary endpoint was time from randomization to death or confirmed virologic failure ([VF]) (plasma HIV RNA<1 log(10) below baseline 12 weeks after treatment initiation, or ≥400 copies/ml at or after 24 weeks), with comparison between treatments based on hazard ratios (HRs) in intention-to-treat analysis. Equivalence of randomized treatments was defined as finding the 95% CI for HR for virological failure or death in the range 0.5 to 2.0. Baseline characteristics were (median): age = 34 years, CD4 = 121 cells/mm(3), HIV RNA = 5.2 log(10)copies/ml. Median follow-up = 118 weeks; 29 (6%) women were lost to follow-up. 42 women (37 VFs, five deaths; 17%) in the NVP and 50 (43 VFs, seven deaths; 20%) in the LPV/r arm reached the primary endpoint (HR 0.85, 95% CI 0.56-1.29). During initial assigned treatment, 14% and 16% of women receiving NVP and LPV/r experienced grade 3/4 signs/symptoms and 26% and 22% experienced grade 3/4 laboratory abnormalities. However, 35 (14%) women discontinued NVP because of adverse events, most in the first 8 weeks, versus none for LPV/r (p<0.001). VF, death, or permanent treatment discontinuation occurred in 80 (32%) of NVP and 54 (22%) of LPV/r arms (HR = 1.7, 95% CI 1.2-2.4), with the difference primarily due to more treatment discontinuation in the NVP arm. 13 (45%) of 29 women tested in the NVP versus six (15%) of 40 in the LPV/r arm had any drug resistance mutation at time of VF.

CONCLUSIONS

Initial ART with NVP+TDF/FTC demonstrated equivalent virologic efficacy but higher rates of treatment discontinuation and new drug resistance compared with LPV/r+TDF/FTC in antiretroviral-naïve women with CD4<200 cells/mm(3).

TRIAL REGISTRATION

ClinicalTrials.gov NCT00089505.

A randomised comparison of safety and efficacy of nevirapine vs. atazanavir/ritonavir combined with tenofovir/emtricitabine in treatment-naïve patients

BACKGROUND

We report data from NEWART, a randomised phase 4 clinical trial comparing virologic efficacy and safety of nevirapine (NVP) vs. ritonavir-boosted atazanavir (ATV/r) on a background of tenofovir/emtricitabine (TDF/FTC) in HIV-1-infected treatment-naïve patients. This study enrolled patients according to CD4-based initiation criteria for NVP (<250 cells/mm(3) for women and <400 cells/mm(3) for men), to reduce the likelihood of symptomatic hepatic events. NEWART was designed to support and confirm results from ARTEN, an international trial with similar design and study endpoints.

METHODS

A total of 152 patients were randomised 1 : 1 to open-label NVP 200 mg twice daily or ATV/r (300/100 mg) once daily, plus once daily TDF/FTC (300/200 mg). All participants met CD4(+) guidelines at entry. The primary endpoint for non-inferiority was virologic response prior to and at week 48 (confirmed HIV plasma viral load <50 copies/ml, without rebound or change in ARVs). Safety data, including plasma lipids, were recorded throughout the study.

RESULTS

The primary endpoint was achieved in 46/75 (61.3%) and 50/77 (64.9%) of patients taking NVP and ATV/r, respectively. Frequency of adverse events (AEs) was similar between arms, with 88.0% of NVP-treated patients and 94.8% of ATV/r-treated patients experiencing at least one AE. Nine patients (12%) in each arm experienced an AE that led to discontinuation. At week 48, a significantly greater increase was seen in mean plasma HDL cholesterol (HDL-C) in the NVP arm (9.6 mg/dl) vs. the ATV/r arm (3.5 mg/dl); p = 0.016. Also, total cholesterol (TC):HDL-C ratio on-treatment was -0.38 and -0.02 for the NVP and ATV/r arms, respectively (p = 0.038).

CONCLUSIONS

Efficacy results were consistent with the ARTEN study demonstrating that NVP was non-inferior to ATV/r when taken in combination with TDF/FTC. Rates of AEs were similar between the two arms, whereas HDL-C increased and TC:HDL-C decreased significantly more in patients taking NVP than ATV/r.

Guidelines for the use of extended-release nevirapine in HIV-infected patients

INTRODUCTION

Nevirapine (NVP) was the first non-nucleoside reverse transcriptase inhibitor (NNRTI) approved for the treatment of HIV infection and quickly became one of the most extensively used antiretrovirals (ARVs) worldwide. A new extended-formulation of the drug has now been FDA approved for once-daily use.

AREAS COVERED

Two recent, randomized and controlled clinical trials have established the clinical noninferiority of a new, extended-release formulation of NVP (NVP XR), in both treatment-naive and treatment-experienced patients. VERxVE demonstrated the noninferiority of NVP XR in treatment-naive patients. Treatment-experienced patients already stable on the NVP immediate-release formulation (NVP IR) were safely transitioned directly to NVP XR in the TRANxITION study.

EXPERT OPINION

The advantage of the extended release formulation of NVP is that it permits once-daily dosing, while demonstrating safety and efficacy results that are noninferior to that of the twice-daily formulation. It is expected that patients who are on NVP IR at present will consider switching to NVP XR to achieve regimen simplification by reducing their daily dosing and pill burden. In addition, treatment-naive patients who are considering starting on an NVP-based ARV regimen will probably transition to the extended-release formulation once they have successfully initiated NVP therapy according to current guidelines.

Optimizing antiretroviral product selection: a sample approach to improving patient outcomes, saving money, and scaling-up health services in developing countries

Over the last decade, increased funding to support HIV treatment programs has enabled millions of new patients in developing countries to access the medications they need. Today, although demand for antiretrovirals continues to grow, the financial crisis has severely constrained funding leaving countries with difficult choices on program prioritization. Product optimization is one solution countries can pursue to continue to improve patient care while also uncovering savings that can be used for further scale up or other health system needs. Program managers can make procurement decisions that actually reduce program costs by considering additional factors beyond World Health Organization guidelines when making procurement decisions. These include in-country product availability, convenience, price, and logistics such as supply chain implications and laboratory testing requirements. Three immediate product selection opportunities in the HIV space include using boosted atazanavir in place of lopinovir for second-line therapy, lamivudine instead of emtricitabine in both first-line and second-line therapy, and tenofovir + lamivudine over abacavir + didanosine in second-line therapy. If these 3 opportunities were broadly implemented in sub-Saharan Africa and India today, approximately $300 million of savings would be realized over the next 5 years, enabling hundreds of thousands of additional patients to be treated. Although the discussion herein is specific to antriretrovirals, the principles of product selection are generalizable to diseases with multiple treatment options and fungible commodity procurement. Identifying and implementing approaches to overcome health system inefficiencies will help sustain and may expand quality care in resource-limited settings.

Clinical experience with nevirapine combined with tenofovir plus emtricitabine or lamivudine-containing regimens in HIV-infected subjects

We retrospectively evaluated the durability and reasons for discontinuation of nevirapine (NVP) in combination with a tenofovir (TDF) and emtricitabine (FTC) or lamivudine (3TC)-containing antiretroviral therapy (ART) regimen in an Australian outpatient setting. Between January 2003 and June 2009, 64 patients (29 naïve and 35 treatment-experienced) received NVP/TDF-based regimens. The median exposure was 13.0 months (interquartile range [IQR] 6.0-20.0 months). The two- and three-year probability of continuing a NVP/TDF with FTC or 3TC regimen was 76% and 70%, respectively. Thirteen (20.3%) patients discontinued their regimen during the observation period. Reasons for discontinuation included virological failure in four (6.3%), rash in three (4.7%), lost to follow-up in three (4.7%), liver toxicity in two (3.1%) and HIV-1-related encephalopathy in one (1.6%). Long-term follow-up with a NVP/TDF-based regimen showed a low rate of discontinuation and enabled physicians to extend the use of ART over a long period, often with simplified (once-daily) regimens.

Tenofovir or zidovudine in three-drug combination therapy with one nucleoside reverse transcriptase inhibitor and one non-nucleoside reverse transcriptase inhibitor for initial treatment of HIV infection in antiretroviral-naïve individuals

BACKGROUND

The introduction of highly active antiretroviral therapy (ART) as treatment for HIV infection has greatly improved mortality and morbidity for adults and children living with HIV around the world. Two of the most common medications given in first-line ART are the nucleoside reverse transcriptase inhibitor (NRTI) zidovudine (AZT) and the nucleotide reverse transcriptase inhibitor (NtRTI) tenofovir (TDF).

OBJECTIVES

To assess the efficacy, safety, and tolerability of TDF compared with AZT in combination with one NRTI and one non-nucleoside reverse transcriptase inhibitor (NNRTI) as part of first-line ART for HIV-infected people in resource-limited settings

SEARCH STRATEGY

Standard Cochrane methods were used to search electronic databases and conference proceedings with relevant search terms without limits to language.

SELECTION CRITERIA

Randomised controlled trials of HIV-infected patients aged 5 years and older were included. Primary outcomes of interest included mortality, serious adverse events, virologic response to ART, and adherence/tolerance/retention. Secondary outcomes included immunologic response to ART, development of ART drug resistance, and prevention of sexual transmission of HIV.

DATA COLLECTION AND ANALYSIS

Two authors assessed each reference for inclusion and exclusion criteria established a priori. Data were abstracted independently using a standardised abstraction form.

MAIN RESULTS

Two randomised controlled trials contributed to this literature, enrolling 586 participants, and found no critical difference between TDF and AZT in regards to serious adverse events or virologic response. The trials did find higher rates of adherence and immunologic response in TDF-containing regimens compared with those containing AZT. The quality of the literature to support this conclusion is moderate to high. Drug resistance was more common for TDF than AZT, but the quality of this literature is low, with only one study reporting this outcome. It should be noted that the two studies compared two different drugs in addition to TDF and AZT; one had lamivudine (3TC) and nevirapine (NVP) and the other had emtricitabine (FTC) and efavirenz (EFV).

AUTHORS' CONCLUSIONS

We conclude that for the critical outcomes of virologic response and serious adverse events, initial ART regimens containing TDF are equivalent to those containing AZT. However, TDF is superior to AZT in terms of immunologic response and adherence and less frequent emergence of resistance. How much the other drugs in the regimens contributed to these findings is unclear, and true head-to-head trials are still warranted. The role of each drug in initial ART likely will be driven by their specific toxicities.

Safety and efficacy of tenofovir/emtricitabine plus nevirapine in HIV-infected patients

All 178 HIV-infected individuals who had initiated tenofovir-emtricitabine-nevirapine (TDF/FTC/NVP) at our institution and were adherent to their medication were retrospectively examined. Only 22% were antiretroviral naive. After a median follow-up of 16 months, only five (2.8%) individuals (all with prior exposure to other antiretroviral regimens) experienced virological failure. In all instances, viral rebound occurred after 12 weeks of therapy. These results do not support an increased risk of early virological failure using TDF/FTC/NVP.

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.

High rate of early virological failure with the once-daily tenofovir/lamivudine/nevirapine combination in naive HIV-1-infected patients

BACKGROUND

The combination of one non-nucleoside reverse transcriptase inhibitor (NNRTI) with two nucleoside reverse transcriptase inhibitors is a validated first-line antiretroviral (ARV) therapy. The once-daily combination of lamivudine, tenofovirDF and nevirapine has not been evaluated in a clinical trial.

METHODS

Randomized, open-label, multicentre, non-inferiority trial comparing lamivudine, tenofovirDF and nevirapine once daily (Group 2) with zidovudine/lamivudine and nevirapine twice daily (Group 1), in naive HIV-1-infected patients with a CD4 count <350/mm(3). We planned to enroll 250 patients.

RESULTS

As of May 2006, 71 patients had been enrolled (35 in Group 1 and 36 in Group 2) and an unplanned interim analysis was done. The groups were comparable at baseline: median CD4 count was 195 and 191/mm(3) and median plasma viral load was 4.9 log(10) and 5.01 log(10), respectively, in Groups 1 and 2. Eight early non-responses (22.2%) were observed, all in Group 2, while two later viral rebounds occurred. Resistance genotypes for the nine Group 2 failing patients showed the mutations M184V/I (n = 3), K65R (n = 6), one or more NNRTI resistance mutations in all cases. At baseline, the nine Group 2 patients who failed had higher median plasma viral load (5.4 log(10)) and lower median CD4 count (110/mm(3)) than the other Group 2 patients (4.7 log(10), P = 0.002 and 223/mm(3), P = 0.004). Nevirapine trough concentrations were not different between the two groups, nor between patients with full viral suppression or those who failed in Group 2. Due to slow recruitment, and those results, the steering committee decided to stop the trial at 12 months.

CONCLUSIONS

In ARV-naive HIV-1-infected patients, the once-daily lamivudine, tenofovirDF and nevirapine regimen resulted in a high rate of early virological failures. The reasons for the failures remain unclear.