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

Impact of Human Immunodeficiency Virus Drug Resistance Mutations Detected in Women Prior to Antiretroviral Therapy With Efavirenz + Tenofovir Disoproxil Fumarate + Lamivudine (or Emtricitabine)

Background

Two large studies suggest that resistance mutations to only nonnucleoside reverse transcriptase inhibitors (NNRTI) did not increase the risk of virologic failure during antiretroviral therapy (ART) with efavirenz/tenofovir disoproxil fumarate/lamivudine (or emtricitabine). We retrospectively evaluated a third cohort to determine the impact of NNRTI resistance on the efficacy of efavirenz-based ART.

Methods

Postpartum women living with human immunodeficiency virus (HIV) were studied if they initiated efavirenz-based ART because of the World Health Organization's recommendation for universal ART. Resistance was detected by Sanger genotyping plasma prior to efavirenz-based ART and at virologic failure (HIV RNA >400 copies/mL). Logistic regression examined relationships between pre-efavirenz genotypes and virologic failure.

Results

Pre-efavirenz resistance was detected in 169 of 1223 (13.8%) participants. By month 12 of efavirenz-based ART, 189 of 1233 (15.3%) participants had virologic failure. Rates of virologic failure did not differ by pre-efavirenz NNRTI resistance. However, while pre-efavirenz nucleos(t)ide reverse transcriptase inhibitors (NRTI) and NNRTI resistance was rare (8/1223 [0.7%]) this genotype increased the odds (adjusted odds ratio, 11.2 [95% confidence interval, 2.21-72.2]) of virologic failure during efavirenz-based ART. Age, time interval between last viremic visit and efavirenz initiation, clinical site, viremia at delivery, hepatitis B virus coinfection, and antepartum regimen were also associated with virologic failure.

Conclusions

Resistance to NNRTI alone was prevalent and dual-class (NRTI and NNRTI) resistance was rare in this cohort, with only the latter associated with virologic failure. This confirms others' findings that, if needed, efavirenz-based ART offers most people an effective alternative to dolutegravir-based ART.

Associations of modern initial antiretroviral therapy regimens with all-cause mortality in people living with HIV in resource-limited settings: a retrospective multicenter cohort study in China

Despite the proven virological advantages, there remains some controversy regarding whether first-line integrase strand transfer inhibitors (INSTIs)-based antiretroviral therapy (ART) contributes to reducing mortality of people living with HIV (PLHIV) in clinical practice. Here we report a retrospective study comparing all-cause mortality among PLHIV in China who were on different initial ART regimens (nevirapine, efavirenz, dolutegravir, lopinavir, and others [including darunavir, raltegravie, elvitegravir and rilpivirine]) between 2017 and 2019. A total of 41,018 individuals were included across China, representing 21.3% of newly reported HIV/AIDS cases collectively in the country during this period. Only the differences in all-cause mortality of PLHIV between the efavirenz group and the nevirapine group, the dolutegravir group and the nevirapine group, and the lopinavir group and the nevirapine group, were observed in China. After stratifying the cause of mortality, we found that the differences in mortality between initial ART regimens were mainly observed in AIDS-related mortality.

Adherence to antiretroviral therapy and associated factors among human immunodeficiency -positive patients accessing treatment at health centers in East Gojjam Zone, Northwest Ethiopia, 2019: Community-based cross-sectional study

Background

To achieve an effective treatment outcome, Antiretroviral Therapy (ART) for people living with the Human immunodeficiency virus (HIV) needs at least a 95% adherence level. The aim was to assess adherence to antiretroviral therapy and its associated factors among patients accessing treatment at Health centers in East Gojjam Zone, Northwest Ethiopia.

Methods

A community-based cross-sectional study was conducted on 770 HIV-positive patients from April 1 to May 10, 2019, in East Gojjam Zone. The study participants were selected by simple random computerized sampling methods. Primary data was collected from the patients through face-to-face interviews and home-to-home visits. Bivariable and multivariable binary logistic regression analyses were done. Independent variables with a P-value of <0.2 in bivariable binary logistic regression analysis were considered for multivariable binary logistic regression analysis. A P-value of <0.05 was used as the cut-off point for the presence of statistical significance.

Results

About 396 (51.8%) of the study participants had good adherence. Being 18-24 years old [Adjusted Odd Ratio (AOR) = 0.43; 95% CI = 0.21-0.86], having a marital status of being widowed (AOR = 0.29; 95% CI = 0.14-0.58), having a disease duration of >10 years (AOR = 0.47; 95% CI = 0.24-0.94), taking a drug regimen of Tenofovir (TDF) + Lamivudine (3 TC) + Nevirapine (NVP) (AOR = 2.94; 95% CI = 1.406.15), not being socially stigmatized (AOR = 0.52; 95% CI = 0.34-0.78), and having not encountered an opportunistic infection (AOR = 3.91; 95% CI = 2.68-5.72) were significant factors.

Conclusions

The level of adherence was low. Opportunistic infection prevention, reduction of social stigma, and other intervention activities should be strengthened to increase the level of adherence.

In Vitro Susceptibility of HIV Isolates with High Growth Capability to Antiretroviral Drugs

It has been considered that reduced susceptibility to antiretroviral drugs is influenced by drug adherence, drug tolerance and drug-resistance-related mutations in the HIV genome. In the present study, we assessed the intrinsic high viral growth capability as a potential viral factor that may influence their susceptibility to antiretroviral drugs using an in vitro model. Phytohemagglutinin-activated peripheral blood mononuclear cells (1.5 × 10⁶ cells) were infected with HIV isolates (10⁶ copies/mL). The culture was carried out at different concentrations (0.001-20 μM) of 13 synthetic antiretroviral compounds (six nucleoside/nucleotide reverse transcriptase inhibitors, one non-nucleoside reverse transcriptase inhibitor, four integrase inhibitors, and two protease inhibitors), and HIV production was assessed using HIV-RNA copies in culture. The 90% inhibitory concentration (IC₉₀) and pharmacokinetics of an antiretroviral agent were used as parameters to determine the reduced antiretroviral drug susceptibility of HIV isolates with high growth capability to synthetic antiretroviral compounds. The high growth capability of HIV isolates without any known drug resistance-related mutation affected their susceptibility to tenofovir (IC₉₀ = 2.05 ± 0.40 μM), lamivudine (IC₉₀ = 6.83 ± 3.96 μM), emtricitabine (IC₉₀ = 0.68 ± 0.37 μM), and efavirenz (IC₉₀ = 3.65 ± 0.77 μM). These antiretroviral drugs showed IC₉₀ values close to or above the maximum plasma concentration against HIV isolates with high growth capability without any known drug resistance-related mutation. Our results may contribute to the development of effective strategies to tailor and individualize antiretroviral therapy in patients harboring HIV isolates with high growth capability.

Association of Virologic Failure and Nonnucleoside Reverse Transcriptase Inhibitor Resistance Found in Antiretroviral-Naive Children Infected With Human Immunodeficiency Virus and Given Efavirenz-Based Treatment

Among 66 antiretroviral-naive children aged <3 years with human immunodeficiency virus (HIV) or coinfected with HIV and tuberculosis and initiating efavirenz-based antiretroviral therapy (ART), non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance was detected before ART in 5 (7.6%). Virologic failure occurred in 2 of these children; they were last tested at 16 and 24 weeks of ART. Pre-ART NNRTI resistance was not associated with virologic failure.

Pre-treatment HIV-drug resistance associated with virologic outcome of first-line NNRTI-antiretroviral therapy: A cohort study in Kenya

BACKGROUND

Pre-treatment HIV-drug-resistance (PDR) to WHO-recommended 1st-line non-nucleoside reverse transcriptase inhibitors (NNRTI)-based antiretroviral treatment (ART) is increasing in low-resource communities. We evaluated the risk of PDR on treatment failure if detected at single or multiple codons, at minority (2-9%) or higher (≥10%) frequencies during efavirenz- vs. nevirapine-ART.

METHODS

We conducted a pooled analysis across three cohorts of Kenyans initiating 1st-line NNRTI-ART between 2006 and 2014. Mutations K103N, Y181C, G190A, M184V and K65R were detected by an oligonucleotide ligation assay (OLA) and confirmed by Sanger and next-generation sequencing (NGS). PDR was defined as detection of any mutation by OLA when confirmed by NGS. Treatment failure, defined as plasma HIV RNA ≥400 copies/mL at month-12 of ART, was compared by PDR genotypes.

FINDINGS

PDR was detected in 59/1231 (4·8%) participants. Compared to wild-type genotypes, PDR in participants prescribed nevirapine-ART was associated with increased treatment failure [PDR 69·2% (27/39) vs. wild-type 10·4% (70/674); p = 0·0001], whether detected as minority [66·7% (4/6)] or higher [69·7% (23/33)] frequencies in an individual's HIV quasispecies (p = 0·002 and p < 0·0001, respectively), or mutations at single [50·0% (12/24)] or multiple [100·0% (15/15)] codons (p < 0·0001). During efavirenz-ART, PDR was also associated with increased virologic failure [PDR 25·0% (5/20) vs. wild-type 5·0% (25/498); p = 0·005], but only if detected at multiple drug-resistant codons [50·0% (3/6); p = 0·003] or high frequencies PDR [33·3% (5/15); p = 0·001].

INTERPRETATION

The risk that PDR confers for treatment failure varies by number of mutant codons and their frequency in the quasispecies, with a lower risk for efavirenz- compared to nevirapine-based regimens. PDR detection and management could extend the effective use of efavirenz-ART in low-resource settings.

FUNDING

NIH, PEPFAR.

Viral suppression in adults, adolescents and children receiving antiretroviral therapy in Cameroon: adolescents at high risk of virological failure in the era of "test and treat"

BACKGROUND

After the launching of the « Test & Treat » strategy and the wider accessibility to viral load (VL), evaluating virological success (VS) would help in meeting the UNAIDS targets by 2020 in Cameroon.

SETTING AND METHODS

Cross-sectional study conducted in the Chantal BIYA International Reference Centre for research on HIV/AIDS prevention and management (CIRCB), Yaoundé, Cameroon; data generated between October 2016 and August 2017 amongst adults, adolescents and children at 12, 24, 36 and ≥ 48 months on ART. VS was defined as < 1000 copies/mL of blood plasma and controlled viremia as VL < 50 copies/mL. Data were analysed by SPSS; p < 0.05 considered as significant.

RESULTS

1946 patients (70% female) were enrolled (1800 adults, 105 adolescents, 41 children); 1841 were on NNRTI-based and 105 on PI-based therapy; with 346 patients at M12, 270 at M24, 205 at M36 and 1125 at ≥ M48. The median (IQR) duration on was 48 months (24-48). Overall, VS was 79.4% (95% CI 77.6-81.2) and 67.1% (95% CI 64.9-69.1) had controlled viral replication. On NNRTI-based, VS was 79.9% vs. 71.4% on PIs-based, p = 0.003. By ART duration, VS was 84.1% (M12), 85.9% (M24), 75.1% (M36) and 77.2% (≥ M48), p = 0.001. By age, VS was 75.6% (children), 53.3% (adolescents) and 81.1% (adults), p < 0.001.

CONCLUSIONS

In this sub-population of patients receiving ART in Cameroon, about 80% might be experiencing VS, with declining performance at adolescence, with NNRTI-based regimens, and as from 36 months on ART. Thus, improving VS may require an adapted adherence support mechanism, especially for adolescents with long-term treatment in resource-limited settings.

Impact of Next-generation Sequencing Defined Human Immunodeficiency Virus Pretreatment Drug Resistance on Virological Outcomes in the ANRS 12249 Treatment-as-Prevention Trial

BACKGROUND

Previous studies in human immunodeficiency virus (HIV)-positive individuals on thymidine analogue backbone antiretroviral therapy (ART) with either nevirapine or efavirenz have suggested poorer virological outcomes in the presence of pretreatment drug resistance (PDR). We assessed the impact of PDR on virological suppression (VS; <50 copies/mL) in individuals prescribed primarily tenofovir/emtricitabine/efavirenz in rural KwaZulu-Natal within a treatment-as-prevention trial.

METHODS

Among 1557 HIV-positive individuals who reported no prior ART at study entry and provided plasma samples, 1328 individuals with entry viral load (VL) >1000 copies/mL had next-generation sequencing (NGS) of the HIV pol gene with MiSeq technology. Results were obtained for 1148 individuals, and the presence of PDR was assessed at 5% and 20% detection thresholds. Virological outcome was assessed using Cox regression in 837 of 920 ART initiators with at least 1 follow-up VL after ART initiation.

RESULTS

PDR prevalence was 9.5% (109/1148) and 12.8% (147/1148) at 20% and 5% thresholds, respectively. After a median of 1.36 years (interquartile range, 0.91-2.13), mostly on fixed-dose combination tenofovir/emtricitabine/efavirenz, presence of both nonnucleoside reverse transcriptase inhibitor (NNRTI)/nucleoside reverse transcriptase inhibitor PDR vs no PDR was associated with longer time to VS (adjusted hazard ratio [aHR], 0.32; 95% confidence interval [CI], 0.12-0.86), while there was no difference between those with only NNRTI PDR vs no PDR (aHR, 1.05; 95% CI, 0.82-1.34) at the 5% threshold. Similar differences were observed for mutations detected at the 20% threshold, although without statistical significance.

CONCLUSIONS

NGS uncovered a high prevalence of PDR among participants enrolled in trial clinics in rural KwaZulu-Natal. Dual-class PDR to a mainly tenofovir/emtricitabine/efavirenz regimen was associated with poorer VS. However, there was no impact of NNRTI PDR alone.

CLINICAL TRIALS TEGISTRATION

NCT01509508; South African National Clinical Trials Register: DOH-27-0512-3974.

Impact of initiation of combination antiretroviral therapy according to the WHO recommendations on the survival of HIV-positive patients in Taiwan

BACKGROUND/PURPOSE

Early initiation of antiretroviral therapy (ART) reduces the risks for serious infections and mortality. We aimed to assess the outcomes of initiating ART among HIV-positive Taiwanese according to the CD4 cut-off values by the WHO recommendations.

METHODS

We reviewed medical records of patients with newly diagnosed HIV infection between 2004 and 2015 and 3 groups of patients were defined according to the timing of ART initiation based on CD4 count recommended by WHO: Group 1 between 2004 and 2009; Group 2 between 2010 and 2012; and Group 3 between 2013 and 2015. The primary outcome was all-cause mortality. All patients were followed until 2 years after the last patient was included in each group.

RESULTS

Of 2022 patients included, the mortality rate was 18.28, 14.01, and 9.10 deaths per 1000 person-years of follow-up (PYFU) in Groups 1, 2, and 3, respectively. In multivariable Cox regression analysis, factors associated with mortality were age (per 1-year increase, adjusted hazard ratio [AHR], 1.06; 95% CI, 1.05-1.08), presence of AIDS-defining disease at HIV diagnosis (AHR, 4.81; 95% CI, 2.99-7.74), solid-organ malignancy (AHR, 3.10; 95% CI, 1.86-5.18), and initiation of ART (AHR, 0.09; 95% CI, 0.05-0.16). By competing risk regression model for non-AIDS-related death, the AHR for Group 3 versus Group 1 was 0.27 (95% CI, 0.09-0.80).

CONCLUSIONS

While continued efforts are needed to improve early diagnosis and linkage to care, initiation of cART improved survival among HIV-positive patients in Taiwan according to the increasing CD4 cut-off values that were recommended by the WHO.

HIV-1 drug resistance testing is essential for heavily-treated patients switching from first- to second-line regimens in resource-limited settings: evidence from routine clinical practice in Cameroon

Background

With the phase-out of stavudine (d4T), change to first-line regimens with zidovudine (AZT) or tenofovir (TDF) in resource-limited settings (RLS) might increase risks of cross-resistance to nucleos(t) ide reverse transcriptase inhibitors (NRTI). This would restrict the scope of switching to the World Health Organisation (WHO)-recommended standard second-line combinations (SLC) without HIV drug resistance (HIVDR)-testing in routine clinical practice.

Methods

An observational study was conducted among 101 Cameroonian patients (55.4% male, median [IQR] age 34 [10–41] years) failing first-line antiretroviral therapy (ART) in 2016, and stratified into three groups according to NRTIs exposure: exposure to both thymidine analogues AZT “and” D4T (group-A, n = 55); exposure to both TDF and AZT “or” D4T (group-B, n = 22); exposure solely to D4T (group-C, n = 24). Protease-reverse transcriptase HIVDR was interpreted using the HIVdb penalty scores (≥60: high-resistance; 20–59: intermediate-resistance; < 20: susceptible). The acceptable threshold for potential-efficacy was set at 80%.

Results

The median [IQR] CD4, viral RNA, and time on ART, were respectively 129 [29–466] cells/μl, 71,630 [19,041-368,000] copies/ml, and 4 [2–5] years. Overall HIVDR-level was 89.11% (90/101), with 83.2% harbouring M184 V (high-level 3TC/FTC-resistance) and only 1.98% (2/101) major HIVDR-mutations to ritonavir-boosted protease-inhibitors (PI/r). Thymidine-analogue mutations (TAMs)-1 [T215FY (46.53%), M41 L (22.77%), L210 W (8.91%)], with cross-resistance to AZT and TDF, were higher compared to TAMs-2 [D67N (21.78%), K70R (19.80%), K219QE (18.81%)]. As expected, K65R was related with TDF-exposure: 0% (0/55) in group-A, 22.72% (5/22) group-B, 4.17% (1/24) group-C (p = 0.0013). The potential-efficacy of AZT vs. TDF was respectively 43.64% (24/55) vs. 70.91% (39/55) in group-A (p = 0.0038); 63.64% (14/22) vs. 68.28% (15/22) in group-B (p = 1.0000); and 37.50% (9/24) vs. 83.33% (20/24) in group-C (p = 0.0032). CRF02_AG was the prevailing subtype (63.40%), followed by CRF11.cpx (8.91%), A₁ (7.92%), G (5.94%); without any significant effect of the subtype-distribution on HIVDR (92.2% in CRF02_AG vs. 83.8% in non-AG; p = 0.204).

Conclusion

First-line ART-failure exhibits high-level NRTI-resistance, with potential lower-efficacy of AZT compared to TDF. Significantly, using our 80% efficacy-threshold, only patients without NRTI-substitution on first-line could effectively switch to SLC following the WHO-approach. Patients with multiple NRTI-substitutions (exposed to both thymidine-analogues and TDF) on first-line ART would require HIVDR-testing to select active NRTIs for SLC.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3871-0) contains supplementary material, which is available to authorized users.

Pharmaceutical Services in Mozambique: foreign aid in public provision of medicines

This article examines the activities of national and international actors in Pharmaceutical Services (PS) in Mozambique from 2007 to 2012, focusing on the public provision of HIV/Aids, malaria and tuberculosis medicines. It describes how PS functions in the country, what actors are involved in this area and the relations among them, pursuing salient issues in the modus operandi of partners in cooperation. The methodology combines literature review, document survey and analysis and interviews. The theoretical and analytical framework was given by the policy analysis approach, focusing on the role of the State and its interrelations with other actors in foreign aid in PS, and also by the networks approach. It was concluded that the interactions among the actors involved is complex and characterised by operational fragmentation and overlapping of activities between entities, centralised medicine procurement in the hands of few agents, bypassing of national structures and disregard for the strengthening needed to bolster national health system autonomy. Despite some advances in the provision and availability of medicines for these diseases, external dependence is strong, which undermines the sustainability of PS in Mozambique.

Treatment Outcome and Adverse Events of Tenofovir Disoproxil Fumarate Based Regimens as Compared to Zidovudine Based Regimens Among People Living with HIV/AIDS: A Systematic Review and Meta-Analysis of Observational Studies

Background:

Findings from different studies report inferior clinical and virologic efficacy with TDF/3TC/NVP. But, some studies show that, there was no statistically significant difference in mortality among ZDV and TDF based regimens. The objective of this review was to systematically identify, appraise and synthesize the best available evidence on efficacy and safety of TDF based regimen as compared to ZDV based regimens.

Methods:

A three-step search strategy was used to locate published and unpublished studies. First, an initial limited search of google was undertaken followed by analysis of text words. A second extensive search was undertaken. We searched the PubMed, EMBASE, Google Scholar, Medline, and CINHAL. We did the initial search for articles on July 11-18, 2016, and updated the results on May 13, 2017.Third, the reference lists of all identified articles was searched for additional studies.

Results:

ZDV based regimens had better outcome on prevention of mortality (OR=1.31, 95%CI (1.14, 1.50), I² = 0%, Chi² = 2.51), and lower virologic failure (OR = 1.44, 95% CI [1.18, 1.76], chi² = 5.91, P= 0.003, I² =83%) while, TDF based regimens were more tolerable (OR=0.15, 95%CI (0.08, 0.30), I² = 40%, Chi² = 3.31). The difference in incidence of opportunistic infection is not significant (OR = 0.83, 95% CI [0.52, 1.32], chi² = 0.11, P= 0.42, I² =0%).

Conclusion:

There is lower mortality and lower virologic failure in ZDV group, but better safety profile among TDF based regimens.

Long-term viral suppression and immune recovery during first-line antiretroviral therapy: a study of an HIV-infected adult cohort in Hanoi, Vietnam

INTRODUCTION

Achieving viral suppression is key in the global strategy to end the HIV epidemic. However, the levels of viral suppression have yet to be described in many resource-limited settings.

METHODS

We investigated the time to virologic failure (VF; defined as a viral load of ≥1000 copies/ml) and changes in CD4 counts since starting antiretroviral therapy (ART) in a cohort of HIV-infected adults in Hanoi, Vietnam. Factors related to the time to VF and impaired early immune recovery (defined as not attaining an increase in 100 cells/mm³ in CD4 counts at 24 months) were further analysed.

RESULTS

From 1806 participants, 225 were identified as having VF at a median of 50 months of first-line ART. The viral suppression rate at 12 months was 95.5% and survival without VF was maintained above 90% until 42 months. An increase in CD4 counts from the baseline was greater in groups with lower baseline CD4 counts. A younger age (multivariate hazard ratio (HR) 0.75, vs. <30), hepatitis C (HCV)-antibody positivity (HR 1.43), and stavudine (d4T)-containing regimens (HR 1.4, vs. zidovudine (AZT)) were associated with earlier VF. Factors associated with impaired early immune recovery included the male sex (odds ratio (OR) 1.78), HCV-antibody positivity (OR 1.72), d4T-based regimens (OR 0.51, vs. AZT), and nevirapine-based regimens (OR 0.53, vs. efavirenz) after controlling for baseline CD4 counts.

CONCLUSION

Durable high-rate viral suppression was observed in the cohort of patients on first-line ART in Vietnam. Our results highlight the need to increase adherence support among injection drug users and HCV co-infected patients.

High Levels of Dual-Class Drug Resistance in HIV-Infected Children Failing First-Line Antiretroviral Therapy in Southern Ethiopia

Clinical monitoring of pediatric HIV treatment remains a major challenge in settings where drug resistance genotyping is not routinely available. As a result, our understanding of drug resistance, and its impact on subsequent therapeutic regimens available in these settings, remains limited. We investigate the prevalence and correlates of HIV-1 drug resistance among 94 participants of the Ethiopia Pediatric HIV Cohort failing first-line combination antiretroviral therapy (cART) using dried blood spot-based genotyping. Overall, 81% (73/90) of successfully genotyped participants harbored resistance mutations, including 69% (62/90) who harbored resistance to both Nucleoside Reverse Transcriptase Inhibitors (NRTIs) and Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs). Strikingly, 42% of resistant participants harbored resistance to all four NRTIs recommended for second-line use in this setting, meaning that there are effectively no remaining cART options for these children. Longer cART duration and prior regimen changes were significantly associated with detection of drug resistance mutations. Replicate genotyping increased the breadth of drug resistance detected in 34% of cases, and thus is recommended for consideration when typing from blood spots. Implementation of timely drug resistance testing and access to newer antiretrovirals and drug classes are urgently needed to guide clinical decision-making and improve outcomes for HIV-infected children on first-line cART in Ethiopia.

Quantifying an Adherence Path-Specific Effect of Antiretroviral Therapy in the Nigeria PEPFAR Program

Since the early 2000s, evidence has accumulated for a significant differential effect of first-line antiretroviral therapy (ART) regimens on human immunodeficiency virus (HIV) viral load suppression. This finding was replicated in our data from the Harvard President's Emergency Plan for AIDS Relief (PEPFAR) program in Nigeria. Investigators were interested in finding the source of these differences, i.e., understanding the mechanisms through which one regimen outperforms another, particularly via adherence. This question can be naturally formulated via mediation analysis with adherence playing the role of a mediator. Existing mediation analysis results, however, have relied on an assumption of no exposure-induced confounding of the intermediate variable, and generally require an assumption of no unmeasured confounding for nonparametric identification. Both assumptions are violated by the presence of drug toxicity. In this paper, we relax these assumptions and show that certain path-specific effects remain identified under weaker conditions. We focus on the path-specific effect solely mediated by adherence and not by toxicity and propose an estimator for this effect. We illustrate with simulations and present results from a study applying the methodology to the Harvard PEPFAR data. Supplementary materials are available online.

Community Based Antiretroviral Treatment in Rural Zimbabwe

Treatment of HIV has reduced HIV/AIDS-related mortality. Sustaining >90% virologic suppression in sub-Saharan Africa requires decentralized care and prevention services to rural communities. In Zimbabwe, the number of people receiving antiretroviral treatment (ART) has increased rapidly. However, access to treatment monitoring tools such as viral load and drug resistance testing is limited. We assessed virologic treatment outcomes among ART recipients in Nyamutora, a rural community receiving bimonthly ART and prevention services. We enrolled all ART recipients (143) at 6-monthly visits in the Nyamutora community in 2014 and 2015. Whole blood samples were collected in K-EDTA tubes, transported to Harare for CD4 counts and viral load testing, and genotype was obtained in participants with viral loads >1,000 copies/ml. Ages ranged from 2 to 75 years (median 43 years) with a median 42 months on ART at follow-up. Eight of 143 (6%) had viral loads >1,000 copies/ml at one of the 3 visits, 7 on first-line nevirapine (NVP)-based ART and 1 on second-line LPV/r-based ART. Seven participants had sequence data available, and five had drug resistance mutations, K65R, T69N, K101E, K103N, Y181C/I, M184V, and G190A. Virologic failure (p = .001) and drug resistance mutations (p = .01) on first-line NVP-based ART were associated with younger age by univariate exact logistic regression. The participants had high viral suppression (94%) despite less than optimal (NVP based) ART regimens without laboratory monitoring. Virologic failure and drug resistance were higher among children and adolescents. Effective ART delivery to the community achieved high rates of virologic suppression and minimal drug resistance.

On Partial Identification of the Natural Indirect Effect

In causal mediation analysis, nonparametric identification of the natural indirect effect typically relies on, in addition to no unobserved pre-exposure confounding, fundamental assumptions of (i) so-called "cross-world-countterfactuals" independence and (ii) no exposure-induced confounding. When the mediator is binary, bounds for partial identification have been given when neither assumption is made, or alternatively when assuming only (ii). We extend existing bounds to the case of a polytomous mediator, and provide bounds for the case assuming only (i). We apply these bounds to data from the Harvard PEPFAR program in Nigeria, where we evaluate the extent to which the effects of antiretroviral therapy on virological failure are mediated by a patient's adherence, and show that inference on this effect is somewhat sensitive to model assumptions.

Virologic Response to First-line Efavirenz- or Nevirapine-based Antiretroviral Therapy in HIV-infected African Children

BACKGROUND

Poorer virologic response to nevirapine- versus efavirenz-based antiretroviral therapy (ART) has been reported in adult systematic reviews and pediatric studies.

METHODS

We compared drug discontinuation and viral load (VL) response in ART-naïve Ugandan/Zimbabwean children ≥3 years of age initiating ART with clinician-chosen nevirapine versus efavirenz in the ARROW trial. Predictors of suppression <80, <400 and <1000 copies/mL at 36, 48 and 144 weeks were identified using multivariable logistic regression with backwards elimination (P = 0.1).

RESULTS

A total of 445 (53%) children received efavirenz and 391 (47%) nevirapine. Children receiving efavirenz were older (median age, 8.6 vs. 7.5 years nevirapine, P < 0.001) and had higher CD4% (12% vs. 10%, P = 0.05), but similar pre-ART VL (P = 0.17). The initial non-nucleoside-reverse-transcriptase-inhibitor (NNRTI) was permanently discontinued for adverse events in 7 of 445 (2%) children initiating efavirenz versus 9 of 391 (2%) initiating nevirapine (P = 0.46); at switch to second line in 17 versus 23, for tuberculosis in 0 versus 26, for pregnancy in 6 versus 0 and for other reasons in 15 versus 5. Early (36-48 weeks) virologic suppression <80 copies/mL was superior with efavirenz, particularly in children with higher pre-ART VL (P = 0.0004); longer-term suppression was superior with nevirapine in older children (P = 0.05). Early suppression was poorer in the youngest and oldest children, regardless of NNRTI (P = 0.02); longer-term suppression was poorer in those with higher pre-ART VL regardless of NNRTI (P = 0.05). Results were broadly similar for <400 and <1000 copies/mL.

CONCLUSION

Short-term VL suppression favored efavirenz, but long-term relative performance was age dependent, with better suppression in older children with nevirapine, supporting World Health Organization recommendation that nevirapine remains an alternative NNRTI.

Nanoemulgel using a bicephalous heterolipid as a novel approach to enhance transdermal permeation of tenofovir

Improvements in permeation enhancement strategies, such as nanoemulsions (NEs) and nanoemulgels (NEGs), have led to a renewed interest in transdermal drug delivery (TDD). This study aimed to investigate the potential of LLA1E, a novel dendritic permeation enhancer, as an oily phase in the development of a NEG for the TDD of tenofovir (TNF). TNF loaded NEs (TNEs) were prepared and analysed for mean globule diameter (MGD), polydispersity index (PDI), zeta potential (ZP) and morphology. NEGs of the TNEs (TNEGs) were prepared and evaluated for ex vivo transdermal permeation efficacy. The skin integrity before and after the experiments was assessed using histology and transepithelial electrical resistance (TEER). TNEs had a MGD of 129.06±3.35nm, a PDI of 0.192±0.038 and a ZP of 20.9±2.02mV, with an incorporation efficiency of 91.94±0.84%. There was no significant change is these properties after incorporating the TNEs into the hydrogel, as MGD, PDI and ZP of TNEGs were found to be 136.13±5.21nm, 0.182±0.020 and -20.9±2.08mV respectively. Ex vivo permeation studies showed that the TNEG significantly enhanced the TNF permeation by 39.65-fold, with a cumulative amount of 1866.54±108.62μgcm^-2. Histological and TEER assessments showed no permanent effects on the skin by TNEG, indicating that this novel TNEG nanosystem has the potential to translate into clinical trials as treatment alternatives for HIV/AIDs patients.

Immunological outcomes of Tenofovir versus Zidovudine-based regimens among people living with HIV/AIDS: a two years retrospective cohort study

Background

Tenofovir (TDF) based regimen was reported to have better immunological outcomes. Unfortunately, there is limited information regarding the immunologic outcome associated with this regimen in Ethiopia, as its routine utilization in this setting begun since 2013.

Methods

A 2 years retrospective cohort study was conducted at Jimma University Specialized Hospital, 346 km Southwest of Addis Ababa, Ethiopia. A total of 280 patients’ data from September 2012 to July 2014 was extracted from records from February 10, 2015 to March 10, 2015. Records were selected using a simple random sampling technique. Data on socio-demographic, clinical and drug related variables were collected; entered into EpiData 3.1 and analyzed by STATA 13.1. Mixed effect linear regression was performed to assess difference in CD4+ change between groups adjusting for baseline characteristics. The change in predicted CD4 count attributed to each regimen was also assessed by marginal analysis. P < 0.05 for slopes of the random effect linear regression was used as indicators for presence of association.

Results

The mean (SD) duration of cohort follow up was 714.2 (69.6) and 708.8 (78.9) days (P = 0.753) for TDF and AZT groups respectively. The minimum follow up duration was 7.4 and 8.9 months for TDF and AZT groups respectively. Most of TDF (93.6%) and AZT (91.4%) groups completed their follow up, 5 (3.6%) TDF and 6 (4.3%) AZT groups died and 4 (2.9%) TDF and 6 (4.3%) AZT groups were lost for follow-up (P = 0.769). There was statistically significant difference in immunologic recovery between the groups (B = +34.08, 95% CI [7.8, 60.35], P = 0.027) over time. The predicted CD4+ count for TDF/3TC/EFV was (B = +347.65 cells/mm³, P < 0.001) whereas that of AZT/3TC/EFV was (B = +281.54 cells/mm³, P < 0.001).

Conclusions

TDF based regimens have shown more efficacy compared to AZT based regimens though AZT based regimens are more affordable in low income countries like Ethiopia. However, we recommend further study with quality design to assess the prevalence of sub-optimal CD4+ response (net CD4 gain <50 cells/µl/6 month) in this set-up among TDF users.

Clinical Outcomes of Tenofovir Versus Zidovudine-based Regimens Among People Living with HIV/AIDS: a Two Years Retrospective Cohort Study

BACKGROUND

Tenofovir (TDF) based regimen is one of the first line agents that has been utilized routinely since 2013 in Ethiopia. Unfortunately, there is limited information regarding the Clinical outcomes and associated risk factors in this setting, where patients generally present late, have high rates of TB and other infectious conditions.

METHODS

A two year retrospective cohort study was conducted from February 10/2015 to March 10/2015 at Jimma University Specialized Hospital. A total of 280 records were reviewed by including data from September 3, 2012 to July 31, 2014. Records were selected using a simple random sampling technique. Data was collected on socio-demographic, clinical and drug related variables. Data was analyzed using STATA 13.1. Kaplan-Meier and Cox regression were used to compare survival experience and identify independent predictors. Propensity score matching analysis was conducted to elucidate the average treatment effects of each regimen over opportunistic infections.

RESULTS

Of 280 patients, 183(65.36%) were females and 93(33.32%) of females belong to Tenofovir group. Through 24 months analysis, TDF based regimen had a protective effect against death and opportunistic infections (OIs), (AHR=0.79, 95% CI [0.24, 2.62]) and (AHR=0.78, 95%CI [0.43, 1.4] respectively. The average treatment effect of TDF/3TC/EFV was (-71/1000, p=0.026), while it was (+114/1000, p=0.049) for AZT/3TC/EFV. However, TDF/3TC/NVP was associated with statistically insignificant morbidity reduction (-74/1000, p=0.377). Those with body mass-index (BMI) <18.5kg/m2 (AHR=3.21, 95%CI [0.93, 11.97]) had higher hazard of death. Absence of baseline prophylaxis (AHR=8.22, 95% CI [1.7, 39.77]), Cotrimoxazole prophylaxis alone (AHR=6.15, 95% CI [1.47, 26.67]) and BMI<18.5kg/m2 (AHR=2.06, 95% CI [1.14, 3.73]) had higher hazards of OIs.

CONCLUSION

The survival benefit of TDF based regimen was similar to AZT based regimen and therefore can be used as an alternative for HIV/AIDS patients in resource limited setups. However, since this study was not dealt with toxicity of the regimens, we recommend to conduct high quality design on this issue.

Treatment failure and drug resistance in HIV-positive patients on tenofovir-based first-line antiretroviral therapy in western Kenya

Introduction

Tenofovir-based first-line antiretroviral therapy (ART) is recommended globally. To evaluate the impact of its incorporation into the World Health Organization (WHO) guidelines, we examined treatment failure and drug resistance among a cohort of patients on tenofovir-based first-line ART at the Academic Model Providing Access to Healthcare, a large HIV treatment programme in western Kenya.

Methods

We determined viral load (VL), drug resistance and their correlates in patients on ≥six months of tenofovir-based first-line ART. Based on enrolled patients’ characteristics, we described these measures in those with (prior ART group) and without (tenofovir-only group) prior non-tenofovir-based first-line ART using Wilcoxon rank sum and Fisher's exact tests.

Results

Among 333 participants (55% female; median age 41 years; median CD4 336 cells/µL), detectable (>40 copies/mL) VL was found in 18%, and VL>1000 copies/mL (WHO threshold) in 10%. Virologic failure at both thresholds was significantly higher in 217 participants in the tenofovir-only group compared with 116 in the prior ART group using both cut-offs (24% vs. 7% with VL>40 copies/mL; 15% vs. 1% with VL>1000 copies/mL). Failure in the tenofovir-only group was associated with lower CD4 values and advanced WHO stage. In 35 available genotypes from 51 participants in the tenofovir-only group with VL>40 copies/mL (69% subtype A), any resistance was found in 89% and dual-class resistance in 83%. Tenofovir signature mutation K65R occurred in 71% (17/24) of the patients infected with subtype A. Patients with K65R had significantly lower CD4 values, higher WHO stage and more resistance mutations.

Conclusions

In this Kenyan cohort, tenofovir-based first-line ART resulted in good (90%) virologic suppression including high suppression (99%) after switch from non-tenofovir-based ART. Lower virologic suppression (85%) and high observed resistance levels (89%) in the tenofovir-only group impact future treatment options, support recommendations for widespread VL monitoring in such resource limited settings to identify early treatment failure and suggest consideration of individualized resistance testing to design effective subsequent regimens.

Comparison of three quantification methods for the TZM-bl pseudovirus assay for screening of anti-HIV-1 agents

The TZM-bl pseudovirus assay is commonly used to evaluate the efficacy of neutralizing antibodies and small molecular inhibitors in HIV-1 research. Here, to determine the optimal measurement method for screening anti-HIV-1 inhibitors, we compared three measurement methods based on firefly luciferase and β-galactosidase activities. The 50% tissue culture infective doses (TCID50) of the pseudoviruses were determined using the luciferase, β-galactosidase colorimetric, and 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) staining assays. Three commercial reverse-transcriptase inhibitors (azidothymidine, nevirapine, and lamivudine) were tested as reference drugs to compare the reproducibility, linear correlation, and half maximal inhibitory concentration (IC50) values determined using these methods. In the TCID50 assay, the sensitivity of β-galactosidase colorimetric assay was almost 562 times lower than that of the other two methods. Reproducible dose-response curves were obtained for the inhibitors with all methods; the IC50 values of the inhibitors were not significantly different. Linear regression analysis showed linear correlation between methods. Compared to the β-galactosidase colorimetric assay, the other two methods have the advantage of high sensitivity and are less affected by interference. In conclusion, the luciferase and X-gal staining assays, which can be applied either alone or combined, are recommended for anti-HIV-1 inhibitor screening.

Virological responses to lamivudine or emtricitabine when combined with tenofovir and a protease inhibitor in treatment-naïve HIV-1-infected patients in the Dutch AIDS Therapy Evaluation in the Netherlands (ATHENA) cohort

OBJECTIVES

Lamivudine (3TC) and emtricitabine (FTC) are considered interchangeable in recommended tenofovir disoproxil-fumarate (TDF)-containing combination antiretroviral therapies (cARTs). This statement of equivalence has not been systematically studied. We compared the treatment responses to 3TC and FTC combined with TDF in boosted protease inhibitor (PI)-based cART for HIV-1-infected patients.

METHODS

An observational study in the AIDS Therapy Evaluation in the Netherlands (ATHENA) cohort was carried out between 2002 and 2013. Virological failure rates, time to HIV RNA suppression < 400 copies/mL, and time to treatment failure were analysed using multivariable logistic regression and Cox proportional hazard models. Sensitivity analyses included propensity score-adjusted models.

RESULTS

A total of 1582 ART-naïve HIV-1-infected patients initiated 3TC or FTC with TDF and ritonavir-boosted darunavir (29.6%), atazanavir (41.5%), lopinavir (27.1%) or another PI (1.8%). Week 48 virological failure rates on 3TC and FTC were comparable (8.9% and 5.6%, respectively; P = 0.208). The multivariable adjusted odds ratio of virological failure when using 3TC instead of FTC with TDF in PI-based cART was 0.75 [95% confidence interval (CI) 0.32-1.79; P = 0.51]. Propensity score-adjusted models showed comparable results. The adjusted hazard ratio (HR) for treatment failure of 3TC compared with FTC was 1.15 (95% CI 0.58-2.27) within 240 weeks after cART initiation. The time to two consecutive HIV RNA measurements < 400 copies/mL within 48 weeks (HR 0.94; 95% CI 0.78-1.16) and the time to treatment failure after suppression < 400 copies/mL (HR 0.94; 95% CI 0.36-2.50) were not significantly influenced by the use of 3TC in TDF/PI-containing cART.

CONCLUSIONS

The virological responses were not significantly different in treatment-naïve HIV-1-infected patients starting either 3TC/TDF or FTC/TDF and a ritonavir-boosted PI.

Global epidemiology of drug resistance after failure of WHO recommended first-line regimens for adult HIV-1 infection: a multicentre retrospective cohort study

Background

Antiretroviral therapy (ART) is crucial for controlling HIV-1 infection through wide-scale treatment as prevention and pre-exposure prophylaxis (PrEP). Potent tenofovir disoproxil fumarate-containing regimens are increasingly used to treat and prevent HIV, although few data exist for frequency and risk factors of acquired drug resistance in regions hardest hit by the HIV pandemic. We aimed to do a global assessment of drug resistance after virological failure with first-line tenofovir-containing ART.

Methods

The TenoRes collaboration comprises adult HIV treatment cohorts and clinical trials of HIV drug resistance testing in Europe, Latin and North America, sub-Saharan Africa, and Asia. We extracted and harmonised data for patients undergoing genotypic resistance testing after virological failure with a first-line regimen containing tenofovir plus a cytosine analogue (lamivudine or emtricitabine) plus a non-nucleotide reverse-transcriptase inhibitor (NNRTI; efavirenz or nevirapine). We used an individual participant-level meta-analysis and multiple logistic regression to identify covariates associated with drug resistance. Our primary outcome was tenofovir resistance, defined as presence of K65R/N or K70E/G/Q mutations in the reverse transcriptase (RT) gene.

Findings

We included 1926 patients from 36 countries with treatment failure between 1998 and 2015. Prevalence of tenofovir resistance was highest in sub-Saharan Africa (370/654 [57%]). Pre-ART CD4 cell count was the covariate most strongly associated with the development of tenofovir resistance (odds ratio [OR] 1·50, 95% CI 1·27–1·77 for CD4 cell count <100 cells per μL). Use of lamivudine versus emtricitabine increased the risk of tenofovir resistance across regions (OR 1·48, 95% CI 1·20–1·82). Of 700 individuals with tenofovir resistance, 578 (83%) had cytosine analogue resistance (M184V/I mutation), 543 (78%) had major NNRTI resistance, and 457 (65%) had both. The mean plasma viral load at virological failure was similar in individuals with and without tenofovir resistance (145 700 copies per mL [SE 12 480] versus 133 900 copies per mL [SE 16 650; p=0·626]).

Interpretation

We recorded drug resistance in a high proportion of patients after virological failure on a tenofovir-containing first-line regimen across low-income and middle-income regions. Effective surveillance for transmission of drug resistance is crucial.

Funding

The Wellcome Trust.

Efavirenz-based antiretroviral therapy versus nevirapine-including regimens for prevention of mother-to-child transmission of HIV option B plus in resource-limited settings: is there anything missing?

In 2013, an estimated 1.5 million HIV-positive pregnant women gave birth, with 240,000 children worldwide acquiring HIV. More than 90% of new pediatric infections occurred in Sub-Saharan Africa. The latest WHO guidelines recommended efavirenz (EFV)-based antiretroviral therapy as the first-line regimen for prevention of mother-to-child transmission of HIV (PMTCT). On the other hand, some data suggest that nevirapine (NVP), a well-known antiretroviral, could still play a relevant role in PMTCT, especially in resource-limited settings (RLSs) where the fertility rate is dramatically high compared to developed countries. Given the lack of an unanimous consensus and definitive opinions, this paper goes through the reasons for WHO decisions and aims at refreshing the debate about NVP and EFV pros and cons for PMTCT in RLSs.

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.

Assessing efficacy of different nucleos(t)ide backbones in NNRTI-containing regimens in the Swiss HIV Cohort Study

BACKGROUND

The most recommended NRTI combinations as first-line antiretroviral treatment for HIV-1 infection in resource-rich settings are tenofovir/emtricitabine, abacavir/lamivudine, tenofovir/lamivudine and zidovudine/lamivudine. Efficacy studies of these combinations also considering pill numbers, dosing frequencies and ethnicities are rare.

METHODS

We included patients starting first-line combination ART (cART) with or switching from first-line cART without treatment failure to tenofovir/emtricitabine, abacavir/lamivudine, tenofovir/lamivudine and zidovudine/lamivudine plus efavirenz or nevirapine. Cox proportional hazards regression was used to investigate the effect of the different NRTI combinations on two primary outcomes: virological failure (VF) and emergence of NRTI resistance. Additionally, we performed a pill burden analysis and adjusted the model for pill number and dosing frequency.

RESULTS

Failure events per treated patient for the four NRTI combinations were as follows: 19/1858 (tenofovir/emtricitabine), 9/387 (abacavir/lamivudine), 11/344 (tenofovir/lamivudine) and 45/1244 (zidovudine/lamivudine). Compared with tenofovir/emtricitabine, abacavir/lamivudine had an adjusted HR for having VF of 2.01 (95% CI 0.86-4.55), tenofovir/lamivudine 2.89 (1.22-6.88) and zidovudine/lamivudine 2.28 (1.01-5.14), whereas for the emergence of NRTI resistance abacavir/lamivudine had an HR of 1.17 (0.11-12.2), tenofovir/lamivudine 11.3 (2.34-55.3) and zidovudine/lamivudine 4.02 (0.78-20.7). Differences among regimens disappeared when models were additionally adjusted for pill burden. However, non-white patients compared with white patients and higher pill number per day were associated with increased risks of VF and emergence of NRTI resistance: HR of non-white ethnicity for VF was 2.85 (1.64-4.96) and for NRTI resistance 3.54 (1.20-10.4); HR of pill burden for VF was 1.41 (1.01-1.96) and for NRTI resistance 1.72 (0.97-3.02).

CONCLUSIONS

Although VF and emergence of resistance was very low in the population studied, tenofovir/emtricitabine appears to be superior to abacavir/lamivudine, tenofovir/lamivudine and zidovudine/lamivudine. However, it is unclear whether these differences are due to the substances as such or to an association of tenofovir/emtricitabine regimens with lower pill burden.

Virological efficacy with first-line antiretroviral treatment in India: predictors of viral failure and evidence of viral resuppression

OBJECTIVE

Combination antiretroviral therapy (ART) has improved in efficacy, durability and tolerability. Virological efficacy studies in India are limited. We determined incidence and predictors of virological failure among patients initiating first-line ART and described virological resuppression after confirmed failure, with the goal of informing national policy.

METHODS

Therapy-naïve patients initiated on first-line ART as per national guidelines were monitored every 3 months for adherence and virological response over 2 years. Genotyping on baseline samples was performed to assess primary drug resistance. Multivariate Cox regression analysis was used to assess predictors of virological failure.

RESULTS

Virological failure rate among 599 eligible patients was 10.7 failures per 100 person-years. Cumulative failure incidence was 13.2% in the first year and 16.5% over 2 years. Patients initiated on tenofovir had a significantly lower rate of virological failure than those on stavudine or zidovudine (6.7 vs. 11.9 failures per 100 person-years, P = 0.013). Virological failure was independently associated with age <40 years, mean adherence <95%, non-tenofovir-containing regimens and presence of primary drug resistance. In a subset of 311 patients who were reassessed after treatment failure, 19% (11/58) patients resuppressed their viral load to <400 copies/ml after confirmed virological failure.

CONCLUSIONS

Our results support the inclusion of tenofovir as first-line ART in resource-limited settings and a role for regular adherence counselling and virological monitoring for enhanced treatment success. Detection of early virological failure should provide an opportunity to augment adherence counselling and repeat viral load testing before therapy switch is considered.

Effectiveness of a Treatment Switch to Nevirapine plus Tenofovir and Emtricitabine (or Lamivudine) in Adults with HIV-1 Suppressed Viremia

BACKGROUND

Switching subjects with persistently undetectable HIV-1 viremia under antiretroviral treatment (ART) to once-daily tenofovir/emtricitabine (or lamivudine) + nevirapine is a cost-effective and well-tolerated strategy. However, the effectiveness of this approach has not been established.

METHODS

We performed a retrospective study evaluating the rates of treatment failure, virological failure (VF), and variables associated, in all subjects initiating this switch combination in our clinic since 2001. Analyses were performed by a modified intention to treat, where switch due to toxicity equalled failure. The main endpoint was plasma HIV-RNA < 50 copies/mL.

RESULTS

341 patients were treated for a median of 176 (57; 308) weeks. At week 48, 306 (89.7%) subjects had HIV-1 RNA <50 copies/mL, 10 (2.9%) experienced VF, and 25 (7.4%) discontinued the treatment due to toxicity. During the whole follow-up 23 (6.7%) individuals (17 on lamivudine, 6 on emtricitabine; p = 0.034) developed VF and treatment modification due to toxicity occurred in 36 (10.7%). Factors independently associated with VF in a multivariate analysis were: intravenous drug use (HR 1.51; 95%CI 1.12, 2.04), time with undetectable viral load before the switch (HR 0.98; 0.97, 0.99), number of prior NRTIs (HR 1.49; 1.15, 1.93) or NNRTIs (HR 3.22; 1.64, 6.25), and previous NVP (HR 1.54; 1.10, 2.17) or efavirenz (HR 5.76; 1.11, 29.87) unscheduled interruptions. VF was associated with emergence of usual nevirapine mutations (Y181C/I/D, K103N and V106A/I), M184V (n = 16; 12 with lamivudine vs. 4 with emtricitabine, p = 0.04), and K65R (n = 7).

CONCLUSIONS

The rates of treatment failure at 48 weeks, or long-term toxicity or VF with this switch regimen are low and no unexpected mutations or patterns of mutations were selected in subjects with treatment failure.

Toxicity and clinical outcomes in patients with HIV on zidovudine and tenofovir based regimens: a retrospective cohort study

BACKGROUND

Adverse drug reactions are a major concern with zidovudine/stavudine treatment regimens. The less toxic tenofovir regimen is an alternative, but is seldom considered due to the higher costs. This study compared adverse drug reactions and other clinical outcomes resulting from the use of these two treatment regimens in India.

METHODS

Baseline, clinical characteristics and follow-up outcomes were collected by chart reviews of HIV-positive adults and compared using univariate/multivariate analysis, with and without propensity score adjustments.

RESULTS

Data were collected from 129 and 92 patients on zidovudine (with lamivudine and nevirapine) and tenofovir (with emtricitabine and efavirenz) regimens, respectively. Compared to patients receiving the zidovudine regimen, patients receiving the tenofovir regimen had fewer adverse drug reactions (47%, 61/129 vs 11%, 10/92; p<0.01), requiring fewer regimen changes (36%, 47/129 vs 3%, 3/92; p0.01). With the propensity score, the zidovudine regimen had 8 times more adverse drug reactions (p<0.01). Opportunistic infections were similar between regimens without propensity score, while the zidovudine regimen had 1.2 times (p=0.63) more opportunistic infections with propensity score. Patients on the tenofovir regimen gained more weight. Increase in CD4 levels and treatment adherence (>95%) was similar across regimens.

CONCLUSIONS

Patients on a tenofovir regimen have better clinical outcomes and improved general health than patients on the zidovudine regimen.

Long-term virological outcome in children on antiretroviral therapy in the UK and Ireland

Objective:

To assess factors at the start of antiretroviral therapy (ART) associated with long-term virological response in children.

Design:

Multicentre national cohort.

Methods:

Factors associated with viral load below 400 copies/ml by 12 months and virologic failure among children starting 3/4-drug ART in the UK/Irish Collaborative HIV Paediatric Study were assessed using Poisson models.

Results:

Nine hundred and ninety-seven children started ART at a median age of 7.7 years (inter-quartile range 2.9–11.7), 251 (25%) below 3 years: 411 (41%) with efavirenz and two nucleoside reverse transcriptase inhibitors (EFV + 2NRTIs), 264 (26%) with nevirapine and two NRTIs (NVP + 2NRTIs), 119 (12%; 106 NVP, 13 EFV) with non-nucleoside reverse transcriptase inhibitor and three NRTIs (NNRTI + 3NRTIs), and 203 (20%) with boosted protease inhibitor-based regimens. Median follow-up after ART initiation was 5.7 (3.0–8.8) years. Viral load was less than 400 copies/ml by 12 months in 92% [95% confidence interval (CI) 91–94%] of the children. Time to suppression was similar across regimens (P = 0.10), but faster over calendar time, with older age and lower baseline viral load. Three hundred and thirty-nine (34%) children experienced virological failure. Although progression to failure varied by regimen (P < 0.001) and was fastest for NVP + 2NRTIs regimens, risk after 2 years on therapy was similar for EFV + 2NRTIs and NVP + 2NRTIs, and lowest for NNRTI + 3NRTIs regimens (P-interaction = 0.03). Older age, earlier calendar periods and maternal ART exposure were associated with increased failure risk. Early treatment discontinuation for toxicity occurred more frequently for NVP-based regimens, but 5-year cumulative incidence was similar: 6.1% (95% CI 3.9–8.9%) NVP, 8.3% (95% CI 5.6–11.6) EFV, and 9.8% (95% CI 5.7–15.3%) protease inhibitor-based regimens (P = 0.48).

Conclusion:

Viral load suppression by 12 months was high with all regimens. NVP + 3NRTIs regimens were particularly efficacious in the longer term and may be a good alternative to protease inhibitor-based ART in young children.

The relation between efavirenz versus nevirapine and virologic failure in Johannesburg, South Africa

Introduction

Previous research has raised concerns that patients given nevirapine (NVP)-based regimens experience more virologic failure than patients given efavirenz (EFV)-based regimens. We investigated this hypothesis in a cohort of HIV-positive patients at a large HIV treatment clinic in South Africa.

Methods

All antiretroviral therapy (ART)-naïve non-pregnant patients, ≥18 years old, without tuberculosis, who initiated treatment with either NVP or EFV from April 2004 to August 2011 at the Themba Lethu Clinic in Johannesburg, South Africa, were included. Log-binomial regression and modified Poisson regression were used to estimate risk ratios (RR) with 95% confidence intervals (CI) for predictors of virologic failure, virologic suppression, and loss to follow-up (LTF), whereas a Cox proportional hazards model was used to estimate the risk of death, all within one year.

Results

Of 12,840 included patients, 62.0% were female and the median baseline CD4 count was 98 cells/mm³ (36–169). Of these patients, 93.2% initiated an EFV-based regimen. After adjusting for baseline characteristics, no difference in death (adjusted Hazards Ratio (aHR): 0.92; 95% CI: 0.68–1.25), LTF (adjusted Risk Ratio (aRR): 1.00; 95% CI: 0.79–1.25), nor suppression (aRR: 0.98; 95% CI: 0.95–1.00) at one year was found between regimens. Among patients with ≥1 viral load ≥4 months after ART initiation, 4% (n=350) experienced virologic failure within 12 months of initiation. Patients initiating NVP-based regimens were 60% more likely to fail than patients initiating EFV-based regimens (aRR: 1.58; 95% CI: 1.13–2.22).

Conclusions

In this cohort, patients initiating NVP-based regimens experienced more virologic failure than patients initiating EFV-based regimens. Future guidelines should consider the implications of different efficacy profiles when making recommendations for which drugs to prioritize.

Increased virological failure in naive HIV-1-infected patients taking lamivudine compared with emtricitabine in combination with tenofovir and efavirenz or nevirapine in the Dutch nationwide ATHENA cohort

BACKGROUND

Guidelines for treatment of human immunodeficiency virus type 1 (HIV-1) infection consider lamivudine and emtricitabine to be interchangeable components in first-line combination antiretroviral therapy (cART). The evidence for their clinical equivalence in cART is inconsistent. The primary aim of this study was to evaluate the virological responses to lamivudine and emtricitabine in recommended cART.

METHODS

This was an observational study using data from the AIDS Therapy Evaluation in the Netherlands (ATHENA) nationwide HIV cohort. The virological responses to lamivudine and emtricitabine were compared by multivariable adjusted logistic regression and Cox proportional hazard models. Sensitivity analyses included propensity score-adjusted models.

RESULTS

Therapy-naive HIV-1-infected patients without baseline resistance (N = 4740) initiated lamivudine or emtricitabine with efavirenz/tenofovir or nevirapine/tenofovir. The use of lamivudine was associated with more virological failure at week 48 compared to emtricitabine with efavirenz/tenofovir (10.8% vs 3.6%; adjusted odds ratio [AOR], 1.78; 95% confidence interval [CI], 1.11-2.84) and nevirapine/tenofovir (27% vs 11%; AOR, 2.09; 95% CI, 1.25-3.52) in on-treatment analysis. Propensity score-adjusted models and intent-to-treat sensitivity analyses gave comparable results. The adjusted hazard ratio of virological failure at week 240 using lamivudine instead of emtricitabine was 2.35 (95% CI, 1.61-3.42) with efavirenz and 2.01 (95% CI, 1.36-2.98) with nevirapine. The inclusion of lamivudine or emtricitabine in cART did not influence the time to virological suppression within 48 weeks or the probability of virological rebound after successful virological suppression.

CONCLUSIONS

The use of emtricitabine instead of lamivudine as part of cART was associated with better virological responses. These findings are relevant for settings with extensive use of lamivudine and for settings where generic lamivudine will be available.

Cervicovaginal HIV-1 shedding in women taking antiretroviral therapy in Burkina Faso: a longitudinal study

BACKGROUND

Antiretroviral therapy (ART) reduces transmission of HIV-1. However, genital HIV-1 can be detected in patients on ART. We analyzed factors associated with genital HIV-1 shedding among high-risk women on ART in Burkina Faso.

METHODS

Plasma viral load (PVL) and enriched cervicovaginal lavage HIV-1 RNA were measured every 3-6 months for up to 8 years. Random-effects logistic and linear regression models were used to analyze associations of frequency and quantity of genital HIV-1 RNA with behavioral and biological factors, adjusting for within-woman correlation. The lower limit of detection of HIV-1 RNA in plasma and eCVL samples was 300 copies per milliliter.

RESULTS

One hundred and eighty-eight participants initiated ART from 2004 to 2011. PVL was detectable in 16% (171/1050) of visits, in 52% (90/174) of women. Cervicovaginal HIV-1 RNA was detectable in 16% (128/798) of visits with undetectable plasma HIV-1 RNA in 45% (77/170) of women. After adjusting for PVL, detectable cervicovaginal HIV-1 RNA was independently associated with abnormal vaginal discharge and use of nevirapine or zidovudine vs. efavirenz and stavudine, respectively; longer time on ART and hormonal contraception were not associated with increased shedding. The presence of bacterial vaginosis, herpes simplex virus-2 DNA, and the use of nevirapine vs efavirenz were independently associated with an increased quantity of cervicovaginal HIV-1 RNA.

CONCLUSIONS

Certain ART regimens, abnormal vaginal discharge, bacterial vaginosis, and genital herpes simplex virus-2 are associated with HIV-1 cervicovaginal shedding or quantity in women on ART after adjusting for PVL. This may reduce the effectiveness of ART as prevention in high-risk populations.

Trends in mortality and loss to follow-up in HIV care at the Nkongsamba Regional hospital, Cameroon

Background

Access to Human Immunodeficiency Virus (HIV) care has been rolled out in Cameroon in the last decade through decentralised delivery of care and timely initiation of free antiretroviral drugs. We sought to describe the evolution of mortality and loss to follow up (LTFU) and their patient-related determinants at an HIV clinic which is facing significant challenges.

Methods

A retrospective review of point of care data from HIV patients was conducted in June 2012 at Nkongsamba Regional Hospital in Cameroon to establish mortality and LTFU rates. Univariable and multivariable Cox regression models were used to screen for factors associated with the outcomes. Telephone calls were made to trace patients LTFU.

Results

Between June 2005 and December 2010, 2388 HIV infected patients were admitted. Of these, 1858 were aged 15 and above and were included in our analysis. Their median age was 36 years (IQR: 30–44) and they were followed up over a total risk period of 3647.3 person-years (pyrs). The overall mortality rate was 34.6 deaths per 1000 pyrs (95% CI: 29.0-41.1) while the overall LTFU rate was 94.6 per 1000 pyrs (95%CI: 85.1-105.1).The mortality rates steadily rose to a peak of 69.6 deaths per 1000 pyrs in 2009 and then fell drastically to 20.6 per 1000 pyrs in 2010. The LTFU rate increased sharply from 29.7 in 2006 to 138.2 in 2007 and remained virtually stable until 2010. The factors associated with mortality were: being male (aHR = 2.25, 95% CI: 1.58-3.19), clinical disease progression (aHR = 2.0, 95% CI: 1.58-2.53), CD4 count <200 cells/μl (aHR = 3.14, 95% CI: 1.27-7.73), haemoglobin level <10 g/dl (aHR = 2.50, 95% CI: 1.69-3.69). Major factors associated with high LTFU rate were: distance to clinic of over 5 km (aHR = 1.25, 95% CI: 1.00-1.55), being single, having partners with unknown HIV status or taking no treatment and with CD4 count >500 cells/μl. Two- thirds (66.7%) of traced LTFU patients were dead.

Conclusion

Mortality and LTFU rates in our cohort were high but there is evidence that patients’ outcomes are improving. Interventions to address factors associated with high mortality and LTFU should be implemented for optimal results in patient care.

Legal, ethical, and economic implications of breaking down once-daily fixed-dose antiretroviral combinations into their single components for cost reduction

The availability of generic lamivudine in the context of the current economic crisis has raised a new issue in some European countries: breaking up the once-daily fixed-dose antiretroviral combinations (FDAC) of efavirenz/tenofovir/emtricitabine, tenofovir/emtricitabine, or abacavir/lamivudine, in order to administer their components separately, thereby allowing the use of generic lamivudine instead of branded emtricitabine or lamivudine. The legal, ethical, and economic implications of this potential strategy are reviewed, particularly in those patients receiving a once-daily single-tablet regimen. An unfamiliar change in antiretroviral treatment from a successful patient-friendly FDAC into a more complex regimen including separately the components to allow the substitution of one (or some) of them for generic surrogates (in the absence of a generic bioequivalent FDAC) could be discriminatory because it does not guarantee access to equal excellence in healthcare to all citizens. Furthermore, it could violate the principle of non-maleficence by potentially causing harm both at the individual level (hindering adherence and favouring treatment failure and resistance), and at the community level (hampering control of disease transmission and transmission of HIV-1 resistance). Replacing a FDAC with the individual components of that combination should only be permitted when the substituting medication has the same qualitative and quantitative composition of active ingredients, pharmaceutical form, method of administration, dosage and presentation as the medication being replaced, and a randomized study has demonstrated its non-inferiority. Finally, a strict pharma-economic study supporting this change, comparing the effectiveness and the cost of a specific intervention with the best available alternative, should be undertaken before its potential implementation.

Evaluation of four tenofovir-containing regimens as first-line treatments in Cameroon and Senegal: the ANRS 12115 DAYANA Trial

BACKGROUND

The aim of the present study was to determine appropriate tenofovir-based regimens meriting evaluation in large-scale randomized trials among sub-Saharan African patients.

METHODS

This was a randomized open-label 96-week prospective pilot study evaluating four first-line regimens: tenofovir/emtricitabine/nevirapine (group 1), tenofovir/lopinavir/ritonavir (group 2), tenofovir/emtricitabine/zidovudine (group 3) and tenofovir/emtricitabine/efavirenz (group 4) in antiretroviral-naive, HIV-1-infected patients in Senegal and Cameroon. The primary end point was defined as an HIV-1 RNA viral load <50 copies/ml (study detection limit) at week 16 in ≥50% of patients using intention-to-treat analysis.

RESULTS

At baseline, 119 patients included were 34% male, had a median plasma viral load of 5.4 log10 copies/ml and median CD4(+) T-cell count of 200 cells/mm(3) (range 53-358). The primary end point was achieved for groups 1, 3 and 4 (58% [n=31], 62% [n=29] and 53% [n=30], respectively), but not for group 2 (38% [n=29]). At week 96, undetectable HIV-1 RNA had been achieved in 74% of patients in group 1, 38% in group 2, 72% in group 3 and 73% in group 4. Patients with detectable HIV-1 RNA at week 16 were more likely to have baseline HIV-1 RNA≥100,000 copies/ml (adjusted OR 5.56, 95% CI 1.72, 16.67). HIV mutations associated with protease inhibitor resistance emerged in three patients, all of whom were in group 2. Anaemia occurred in two group 3 patients and was the only serious treatment-related adverse event.

CONCLUSIONS

Three efficient and safe tenofovir-based triple regimens were identified; the two-drug regimen (tenofovir/lopinavir/ritonavir) did not achieve the protocol-defined virological threshold of efficacy.

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.

Emergence of HIV drug resistance during first- and second-line antiretroviral therapy in resource-limited settings

INTRODUCTION

Antiretroviral therapy (ART) in resource-limited settings has expanded in the last decade, reaching >8 million individuals and reducing AIDS mortality and morbidity. Continued success of ART programs will require understanding the emergence of HIV drug resistance patterns among individuals in whom treatment has failed and managing ART from both an individual and public health perspective. We review data on the emergence of HIV drug resistance among individuals in whom first-line therapy has failed and clinical and resistance outcomes of those receiving second-line therapy in resource-limited settings.

RESULTS

Resistance surveys among patients initiating first-line nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based therapy suggest that 76%-90% of living patients achieve HIV RNA suppression by 12 months after ART initiation. Among patients with detectable HIV RNA at 12 months, HIV drug resistance, primarily due to M184V and NNRTI mutations, has been identified in 60%-72%, although the antiretroviral activity of proposed second-line regimens has been preserved. Complex mutation patterns, including thymidine-analog mutations, K65R, and multinucleoside mutations, are prevalent among cases of treatment failure identified by clinical or immunologic methods. Approximately 22% of patients receiving second-line therapy do not achieve HIV RNA suppression by 6 months, with poor adherence, rather than HIV drug resistance, driving most failures. Major protease inhibitor resistance at the time of second-line failure ranges from 0% to 50%, but studies are limited.

CONCLUSIONS

Resistance of HIV to first-line therapy is predictable at 12 months when evaluated by means of HIV RNA monitoring and, when detected, largely preserves second-line therapy options. Optimizing adherence, performing resistance surveillance, and improving treatment monitoring are critical for long-term prevention of drug resistance.

Outcomes for efavirenz versus nevirapine-containing regimens for treatment of HIV-1 infection: a systematic review and meta-analysis

INTRODUCTION

There is conflicting evidence and practice regarding the use of the non-nucleoside reverse transcriptase inhibitors (NNRTI) efavirenz (EFV) and nevirapine (NVP) in first-line antiretroviral therapy (ART).

METHODS

We systematically reviewed virological outcomes in HIV-1 infected, treatment-naive patients on regimens containing EFV versus NVP from randomised trials and observational cohort studies. Data sources include PubMed, Embase, the Cochrane Central Register of Controlled Trials and conference proceedings of the International AIDS Society, Conference on Retroviruses and Opportunistic Infections, between 1996 to May 2013. Relative risks (RR) and 95% confidence intervals were synthesized using random-effects meta-analysis. Heterogeneity was assessed using the I(2) statistic, and subgroup analyses performed to assess the potential influence of study design, duration of follow up, location, and tuberculosis treatment. Sensitivity analyses explored the potential influence of different dosages of NVP and different viral load thresholds.

RESULTS

Of 5011 citations retrieved, 38 reports of studies comprising 114 391 patients were included for review. EFV was significantly less likely than NVP to lead to virologic failure in both trials (RR 0.85 [0.73-0.99] I(2) = 0%) and observational studies (RR 0.65 [0.59-0.71] I(2) = 54%). EFV was more likely to achieve virologic success than NVP, though marginally significant, in both randomised controlled trials (RR 1.04 [1.00-1.08] I(2) = 0%) and observational studies (RR 1.06 [1.00-1.12] I(2) = 68%).

CONCLUSION

EFV-based first line ART is significantly less likely to lead to virologic failure compared to NVP-based ART. This finding supports the use of EFV as the preferred NNRTI in first-line treatment regimen for HIV treatment, particularly in resource limited settings.

Trends in Genotypic HIV-1 Antiretroviral Resistance between 2006 and 2012 in South African Patients Receiving First- and Second-Line Antiretroviral Treatment Regimens

Objectives

South Africa’s national antiretroviral (ARV) treatment program expanded in 2010 to include the nucleoside reverse transcriptase (RT) inhibitors (NRTI) tenofovir (TDF) for adults and abacavir (ABC) for children. We investigated the associated changes in genotypic drug resistance patterns in patients with first-line ARV treatment failure since the introduction of these drugs, and protease inhibitor (PI) resistance patterns in patients who received ritonavir-boosted lopinavir (LPV/r)-containing therapy.

Methods

We analysed ARV treatment histories and HIV-1 RT and protease mutations in plasma samples submitted to the Tygerberg Academic Hospital National Health Service Laboratory.

Results

Between 2006 and 2012, 1,667 plasma samples from 1,416 ARV-treated patients, including 588 children and infants, were submitted for genotypic resistance testing. Compared with 720 recipients of a d4T or AZT-containing first-line regimen, the 153 recipients of a TDF-containing first-line regimen were more likely to have the RT mutations K65R (46% vs 4.0%; p<0.001), Y115F (10% vs. 0.6%; p<0.001), L74VI (8.5% vs. 1.8%; p<0.001), and K70EGQ (7.8% vs. 0.4%) and recipients of an ABC-containing first-line regimen were more likely to have K65R (17% vs 4.0%; p<0.001), Y115F (30% vs 0.6%; p<0.001), and L74VI (56% vs 1.8%; p<0.001). Among the 490 LPV/r recipients, 55 (11%) had ≥1 LPV-resistance mutations including 45 (9.6%) with intermediate or high-level LPV resistance. Low (20 patients) and intermediate (3 patients) darunavir (DRV) cross resistance was present in 23 (4.6%) patients.

Conclusions

Among patients experiencing virological failure on a first-line regimen containing two NRTI plus one NNRTI, the use of TDF in adults and ABC in children was associated with an increase in four major non- thymidine analogue mutations. In a minority of patients, LPV/r-use was associated with intermediate or high-level LPV resistance with predominantly low-level DRV cross-resistance.

Adverse events associated with nevirapine and efavirenz-based first-line antiretroviral therapy: a systematic review and meta-analysis

INTRODUCTION

Since 2002, the WHO has recommended either nevirapine (NVP) or efavirenz (EFV) as part of first-line antiretroviral therapy. These two drugs are known to have differing toxicity profiles, but the risk of these toxicities overall is not well established.

METHODS

We systematically reviewed adverse events among treatment-naive HIV-positive adults and children receiving either NVP or EFV as part of first-line antiretroviral therapy. The primary outcome was drug discontinuation as a result of any adverse event; specific toxicities were evaluated as secondary outcomes. Point estimates and 95% confidence intervals (95% CIs) were calculated and proportions and odds ratios (ORs) pooled using fixed-effects meta-analysis.

RESULTS

We reviewed data on 26,446 adults and 3975 children from eight randomized trials and 26 prospective cohorts. Overall, adults on NVP were more than two times more likely to discontinue treatment due to any adverse event compared to patients on EFV (OR 2.2, 95% CI 1.9-2.6). Severe hepatotoxicity (OR 3.3, 95% CI 2.5-4.2), severe skin toxicity (OR 3.9, 95% CI 2.5-5.4), and severe hypersensitivity reactions (OR 2.4, 95% CI 1.9-2.9) were more likely to occur among patients on NVP. Patients receiving EFV were more likely to experience severe central nervous system events (OR 3.4, 95% CI 2.1-5.4). Similar associations were seen in children.

DISCUSSION

Compared to NVP, EFV is associated with a lower frequency of severe adverse events, in particular treatment discontinuations. This finding supports a move toward EFV-based therapy as the preferred first-line treatment regimen for HIV treatment within a public health approach.

Nevirapine versus efavirenz for patients co-infected with HIV and tuberculosis: a randomised non-inferiority trial

BACKGROUND

In countries with a high incidence of HIV and tuberculosis co-infection, nevirapine and efavirenz are widely used as antiretroviral therapy but both interact with antituberculosis drugs. We aimed to compare efficacy and safety of a nevirapine-based antiretroviral therapy (started at full dose) with an efavirenz-based regimen in co-infected patients.

METHODS

We did a multicentre, open-label, randomised, non-inferiority trial at three health centres in Maputo, Mozambique. We enrolled adults (≥18 years) with tuberculosis and previously untreated HIV infection (CD4 cell counts <250 cells per μL) and alanine aminotransferase and total bilirubin concentrations of less than five times the upper limit of normal. 4-6 weeks after the start of tuberculosis treatment, we randomly allocated patients (1:1) with central randomisation, block sizes of two to six, and stratified by site and CD4 cell count to nevirapine (200 mg twice daily) or efavirenz (600 mg once daily), plus lamivudine and stavudine. The primary endpoint was virological suppression at 48 weeks (HIV-1 RNA <50 copies per mL) in all patients who received at least one dose of study drug (intention-to-treat population); death and loss to follow-up were recorded as treatment failure. The non-inferiority margin for the difference of efficacy was 10%. We assessed efficacy in intention-to-treat and per-protocol populations and safety in all patients who received study drug. This study is registered with ClinicalTrials.gov, number NCT00495326.

FINDINGS

Between October, 2007, and March, 2010, we enrolled 285 patients into each group. 242 (85%) patients in the nevirapine group and 233 (82%) patients in the efavirenz group completed follow-up. In the intention-to-treat population, 184 patients (64·6%, 95% CI 58·7-70·1) allocated nevirapine achieved virological suppression at week 48, as did 199 patients (69·8%, 64·1-75·1) allocated efavirenz (one-sided 95% CI of the difference of efficacy 11·7%). In the per-protocol population, 170 (70·0%, 63·8-75·7) of 243 patients allocated nevirapine achieved virological suppression at week 48, as did 194 (78·9%, 73·2-83·8) of 246 patients allocated efavirenz (one-sided 95% CI 15·4%). The median CD4 cell count at randomisation was 89 cells per μL. 15 patients substituted nevirapine with efavirenz and six patients substituted efavirenz with nevirapine. 20 patients allocated nevirapine (7%) had grade 3-4 increase of alanine aminotransferase compared with 17 patients allocated efavirenz (6%). Three patients had severe rash after receipt of nevirapine (1%) but no patients did after receipt of efavirenz. 18 patients in the nevirapine group died, as did 17 patients in the efavirenz group.

INTERPRETATION

Although non-inferiority of the nevirapine-regimen was not shown, nevirapine at full dose could be a safe, acceptable alternative for patients unable to tolerate efavirenz.

FUNDING

French Research Agency for HIV/AIDS and hepatitis (ANRS).

The Holý Trinity: the acyclic nucleoside phosphonates

The Holý Trinity was named after Dr Antonín Holý (the Holý Trinity being an Unesco recognized monument in Olomouc, Czech Republic), who together with Dr John C. Martin (Gilead Sciences) and myself pioneered a new class of antiviral agents, the acyclic nucleoside phosphonates. These compounds have revolutionized the antiviral drug field with several drugs that have been approved for the treatment of various DNA virus infections (cidofovir), hepatitis B (adefovir), and AIDS (HIV infection; tenofovir). The latter is also available as its oral prodrug, tenofovir disoproxil fumarate, for the treatment of hepatitis B and in combination with emtricitabine ((-)FTC) for the treatment and prophylaxis of HIV infections and in combination with (-)FTC and other HIV inhibitors, that is, efavirenz, rilpivirine, or elvitegravir (and a pharmacoenhancer thereof, cobicistat), for the treatment of AIDS.