Long-term results of initial therapy with abacavir and Lamivudine combined with Efavirenz, Amprenavir/Ritonavir, or Stavudine

Comparative efficacy and safety of dolutegravir relative to common core agents in treatment-naïve patients infected with HIV-1: a systematic review and network meta-analysis

Background

Network meta-analyses (NMAs) provide comparative treatment effects estimates in the absence of head-to-head randomized controlled trials (RCTs). This NMA compared the efficacy and safety of dolutegravir (DTG) with other recommended or commonly used core antiretroviral agents.

Methods

A systematic review identified phase 3/4 RCTs in treatment-naïve patients with HIV-1 receiving core agents: ritonavir-boosted protease inhibitors (PIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), or integrase strand inhibitors (INSTIs). Efficacy (virologic suppression [VS], CD4⁺ cell count change from baseline) and safety (adverse events [AEs], discontinuations, discontinuation due to AEs, lipid changes) were analyzed at Week 48 using Bayesian NMA methodology, which allowed calculation of probabilistic results. Subgroup analyses were conducted for VS (baseline viral load [VL] ≤/> 100,000copies/mL, ≤/> 500,000copies/mL; baseline CD4⁺ ≤/>200cells/μL). Results were adjusted for the nucleoside/nucleotide reverse transcriptase inhibitors (NRTI) combined with the core agent (except subgroup analyses).

Results

The NMA included 36 studies; 2 additional studies were included in subgroup analyses only. Odds of achieving VS with DTG were statistically superior to PIs (odds ratios [ORs] 1.78–2.59) and NNRTIs (ORs 1.51–1.86), and similar but numerically higher than other INSTIs. CD4⁺ count increase was significantly greater with DTG than PIs (difference: 23.63–31.47 cells/μL) and efavirenz (difference: 34.54 cells/μL), and similar to other core agents. INSTIs were more likely to result in patients achieving VS versus PIs (probability: 76–100%) and NNRTIs (probability: 50–100%), and a greater CD4⁺ count increase versus PIs (probability: 72–100%) and NNRTIs (probability: 60–100%). DTG was more likely to result in patients achieving VS (probability: 94–100%), and a greater CD4⁺ count increase (probability: 53–100%) versus other core agents, including INSTIs (probability: 94–97% and 53–93%, respectively). Safety outcomes with DTG were generally similar to other core agents. In patients with baseline VL > 100,000copies/mL or ≤ 200 CD4⁺cells/μL (18 studies), odds of achieving VS with DTG were superior or similar to other core agents.

Conclusion

INSTI core agents had superior efficacy and similar safety to PIs and NNRTIs at Week 48 in treatment-naïve patients with HIV-1, with DTG being among the most efficacious, including in patients with baseline VL > 100,000copies/mL or ≤ 200 CD4⁺cells/μL, who can be difficult to treat.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3975-6) contains supplementary material, which is available to authorized users.

A model-based comparative meta-analysis of the efficacy of dolutegravir-based and efavirenz-based regimens in HIV-infected patients

Currently, combinations of typical types of antiretroviral agents have been adopted as chemotherapy for human immunodeficiency virus (HIV) infection, comprising two nucleoside analogue reverse transcriptase inhibitors plus one of a non-nucleoside reverse transcriptase inhibitor, an integrase strand-transfer inhibitor, and a protease inhibitor. Although several meta-analyses have been conducted to determine first-line combination antiretroviral therapy, this has yet to be confirmed due to the technical limitation associated. In the present study, we applied a model-based meta-analysis (MBMA) approach, because it allows integration of information from clinical trials with varying dosing, duration, and sampling time points, resulting in enlargement of available data sources. We performed a bibliographic search to identify clinical trials involving dolutegravir (DTG)-based and efavirenz (EFV)-based regimens in HIV-infected, antiretroviral therapy-naïve adults, and then identified 30 independent trial data. The time course of drug effect was described by a consecutive first-order kinetic model and analyzed using the nonlinear mixed effect modeling approach. The developed model suggests that the DTG-based regimen provides a faster-acting and more sustainable drug effect than the EFV-based regimen. Moreover, the drug effect tends to appear more slowly and decay faster in severe patients having higher viral load or smaller baseline CD4 count.

Comparison of 48-week efficacies of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide and nucleoside/nucleotide reverse transcriptase inhibitor-sparing regimens: a systematic review and network meta-analysis

OBJECTIVES

To compare nucleoside/nucleotide reverse transcriptase inhibitor (NRTI)-sparing regimens with tenofovir alafenamide (TAF)-based combinations in HIV-1-infected adults, we performed a network meta-analysis (NMA) to provide estimates of relative efficacy for these two regimens.

METHODS

A systematic literature review (SLR) was performed to identify phase 3/4 randomized controlled clinical trials evaluating the efficacy of commonly used combination antiretroviral therapy (cART) including an NRTI backbone or that of commonly used NRTI-sparing regimens. A Bayesian random-effect model was used to compare virological suppression rates at 48 weeks for NRTI-sparing regimens and elvitegravir/cobicistat/emtricitabine/TAF (E/C/F/TAF).

RESULTS

Twenty-three studies in treatment-naïve patients identified by the SLR were included in the NMA, including four studies assessing NRTI-sparing regimens. In treatment-naïve patients, the probability of achieving virological suppression at 48 weeks was between 40% and 60% higher with E/C/F/TAF than with NRTI-sparing strategies. The credible interval vs. darunavir/ritonavir (DVR/r) + raltegravir (RAL) and LPV/r monotherapy did not include 1. In the subgroup of naïve patients with viral load < 100 000 HIV-1 RNA copies/mL, a credible difference was found between NRTI-sparing treatments and E/C/F/TAF. Studies in treatment-experienced patients were too heterogeneous to allow for an NMA.

CONCLUSIONS

The NMA results suggest that E/C/F/TAF represents a more effective option than NRTI-sparing regimens in terms of 48-week efficacy in treatment-naïve patients. Furthermore, TAF pharmacological properties, as well as tolerability results in clinical studies, suggest a safety profile similar to that of NRTI-sparing regimens. Thus, the E/C/F/TAF combination might represent a more appropriate option than NRTI-sparing regimens for initiation of antiretroviral therapy in treatment-naïve HIV-infected patients.

Effectiveness and safety of generic version of abacavir/lamivudine and efavirenz in treatment naïve HIV-infected patients: a nonrandomized, open-label, phase IV study in Cali-Colombia, 2011-2012

Background

Generic drug policies are often associated with concerns about the quality and effectiveness of these products. Phase IV clinical trials may be a suitable design to assess the effectiveness and safety of generic drugs. The objective of this study was to describe the effectiveness and the safety of the generic abacavir/lamivudine and efavirenz in treatment-naïve HIV-infected patients.

Methods

A monocentric, nonrandomized, open-label, phase IV study in treatment naïve HIV-infected patients 18 years or older with indication to receive abacavir/lamivudine and efavirenz were recruited from a program that provides comprehensive outpatient consultation and continuing care. The primary end-point was to achieve viral load <40 copies/mL at 12 months after baseline to assess effectiveness. Secondary end-point of the study were 1) to asses increasing in T-CD4 lymphocytes levels as accompaniment to asses effectiveness, and 2) to assess both gastrointestinal, skin, and central nervous system symptoms, and lipid profile, cardiovascular risk, renal, and hepatic function as safety profile. Data were determined at baseline, 3, 6, and 12 months. Close clinical monitoring and pharmaceutical care were used for data collection. Wilcoxon matched-pairs signed-rank test was used to compare proportions or medians.

Results

Sixty patients were invited to participate in the study; 42 were enrolled and 33 completed the follow-up. Of the nine patients excluded from the study, only one was withdrawn due to adverse events. At 12 months, 31 of 42 patients (73.8 % in intention-to-treat analysis) achieved a viral load of HIV1 RNA <40 copies/mL. There was a significant increase (172 cells/mm³) in the median for CD4 T lymphocyte count. The adverse events were mild and met the safety profile for this antiretroviral regimen, mainly of central nervous system symptoms, skin rash, lipid abnormalities, and an increase of 2 % in the median of the percentage of cardiovascular risk.

Conclusions

The clinical outcomes of generic version of abacavir/lamivudine and efavirenz in HIV treatment naïve patients showed the expected safety and effectiveness profile of proprietary ARV drugs.

Trial registration

Registro Público Cubano de Ensayos Clínicos (RPCEC) ID: RPCEC00000202. Registered 19 November 2015.

Nonnucleoside Reverse-transcriptase Inhibitor- vs Ritonavir-boosted Protease Inhibitor-based Regimens for Initial Treatment of HIV Infection: A Systematic Review and Metaanalysis of Randomized Trials

BACKGROUND

Previous studies suggest that nonnucleoside reverse-transcriptase inhibitors (NNRTIs) cause faster virologic suppression, while ritonavir-boosted protease inhibitors (PI/r) recover more CD4 cells. However, individual trials have not been powered to compare clinical outcomes.

METHODS

We searched databases to identify randomized trials that compared NNRTI- vs PI/r-based initial therapy. A metaanalysis calculated risk ratios (RRs) or mean differences (MDs), as appropriate. Primary outcome was death or progression to AIDS. Secondary outcomes were death, progression to AIDS, and treatment discontinuation. We calculated RR of virologic suppression and MD for an increase in CD4 cells at week 48.

RESULTS

We included 29 trials with 9047 participants. Death or progression to AIDS occurred in 226 participants in the NNRTI arm and in 221 in the PI/r arm (RR, 1.03; 95% confidence interval, .87-1.22; 12 trials; n = 3825), death in 205 participants in the NNRTI arm vs 198 in the PI/r arm (1.04; 0.86-1.25; 22 trials; n = 8311), and progression to AIDS in 140 participants in the NNRTI arm vs 144 in the PI/r arm (1.00; 0.80-1.25; 13 trials; n = 4740). Overall treatment discontinuation (1.12; 0.93-1.35; 24 trials; n = 8249) and from toxicity (1.21; 0.87-1.68; 21 trials; n = 6195) were comparable, but discontinuation due to virologic failure was more common with NNRTI (1.58; 0.91-2.74; 17 trials; n = 5371). At week 48, there was no difference between NNRTI and PI/r in virologic suppression (RR, 1.03; 0.98-1.09) or CD4(+) recovery (MD, -4.7 cells; -14.2 to 4.8).

CONCLUSIONS

We found no difference in clinical and viro-immunologic outcomes between NNRTI- and PI/r-based therapy.

Time to Viremia for Patients Taking their First Antiretroviral Regimen and the Subsequent Resistance Profiles

BACKGROUND

The resistance profiles for patients on first-line antiretroviral therapy (ART) regimens after viremia have not been well studied in community clinic settings in the modern treatment era.

OBJECTIVE

To determine time to viremia and the ART resistance profiles of viremic patients.

METHODS

HIV-positive patients aged ≥16 years initiating a three-drug regimen were retrospectively identified from 01/01/06 to 12/31/12. The regimens were a backbone of two nucleoside reverse transcriptase inhibitors (NRTIs) and a third agent: a protease inhibitor (PI), non-nucleoside reverse transcriptase inhibitor (NNRTI), or an integrase inhibitor (II). Time to viremia was compared using a proportional hazards model, adjusting for demographic and clinical factors. Resistance profiles were described in those with baseline and follow-up genotypes.

RESULTS

For 653 patients, distribution of third-agent use and viremia was: 244 (37%) on PIs with 80 viremia, 364 (56%) on NNRTIs with 84 viremia, and 45 (7%) on II with 11 viremia. Only for NNRTIs, time to viremia was longer than PIs (p = 0.04) for patients with a CD4 count ≥200 cells/mm(3). Of the 175 with viremia, 143 (82%) had baseline and 37 (21%) had follow-up genotype. Upon viremia, emerging ART resistance was rare. One new NNRTI (Y181C) mutation was identified and three patients taking PI-based regimens developed NRTI mutations (M184 V, M184I, and T215Y).

CONCLUSIONS

Time to viremia for NNRTIs was longer than PIs. With viremia, ART resistance rarely developed without PI or II mutations, but with a few NRTI mutations in those taking PI-based regimens, and NNRTI mutations in those taking NNRTI-based regimens.

Comparative Safety and Neuropsychiatric Adverse Events Associated With Efavirenz Use in First-Line Antiretroviral Therapy: A Systematic Review and Meta-Analysis of Randomized Trials

INTRODUCTION

Efavirenz (EFV) is widely used for the treatment of antiretroviral-naive HIV-positive individuals, but there are concerns about the risk of adverse neuropsychiatric events. We systematically reviewed the safety of EFV in first-line therapy.

METHODS

Four databases were searched until October 2014 for randomized trials comparing EFV against non-EFV-based regimens for the treatment of antiretroviral-naive HIV-positive adults and children. The primary outcome was drug discontinuation as a result of any adverse event. Relative risks and proportions were pooled using random-effects meta-analysis.

RESULTS

Forty-two trials were included for review. A lower relative and absolute risk of discontinuations due to adverse drug reactions was seen with EFV compared to nevirapine. The relative and absolute risk of discontinuation was greater for EFV compared with low-dose EFV, rilpivirine, tenofovir, atazanavir, and maraviroc. The relative risk of discontinuation was greater for EFV compared with dolutegravir and raltegravir, but absolute risks were not significantly different. There was no difference in the risk of any severe clinical adverse events for any comparison. With the exception of dizziness, fewer than 10% of patients exposed to EFV experienced any other specific type of neuropsychiatric event. No suicides were reported.

CONCLUSIONS

This review found that over 90% of patients remained on an EFV-based first-line regimen after an average follow-up time of 78 weeks. The relative risk of discontinuations due to adverse events was higher for EFV compared with most other first-line options, but absolute differences were less than 5% for all comparisons.

[GESIDA/National AIDS Plan: Consensus document on antiretroviral therapy in adults infected by the human immunodeficiency virus (Updated January 2015)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines and recommendations for HIV-1 infected adult patients.

METHODS

To formulate these recommendations, a panel composed of members of the AIDS Study Group and the AIDS National Plan (GeSIDA/Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, and cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations, and the evidence that supports them, are based on modified criteria of the Infectious Diseases Society of America.

RESULTS

In this update, cART is recommended for all patients infected by type 1 human immunodeficiency virus (HIV-1). The strength and level of the recommendation depends on the CD4+T-lymphocyte count, the presence of opportunistic diseases or comorbid conditions, age, and prevention of transmission of HIV. The objective of cART is to achieve an undetectable plasma viral load. Initial cART should always comprise a combination of 3 drugs, including 2 nucleoside reverse transcriptase inhibitors, and a third drug from a different family. Three out of the ten recommended regimes are regarded as preferential (all of them with an integrase inhibitor as the third drug), and the other seven (based on a non-nucleoside reverse transcriptase inhibitor, a ritonavir-boosted protease inhibitor, or an integrase inhibitor) as alternatives. This update presents the causes and criteria for switching cART in patients with undetectable plasma viral load, and in cases of virological failure where rescue cART should comprise 3 (or at least 2) drugs that are fully active against the virus. An update is also provided for the specific criteria for cART in special situations (acute infection, HIV-2 infection, and pregnancy) and with comorbid conditions (tuberculosis or other opportunistic infections, kidney disease, liver disease, and cancer).

CONCLUSIONS

These new guidelines update previous recommendations related to cART (when to begin and what drugs should be used), how to monitor and what to do in case of viral failure or drug adverse reactions. cART specific criteria in comorbid patients and special situations are equally updated.

Efavirenz-Based Regimens in Antiretroviral-Naive HIV-Infected Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Efavirenz, a non-nucleoside reverse-transcriptase inhibitor (NNRTI) is one of the most commonly prescribed antiretroviral drugs. The present article provides a systematic overview and meta-analysis of clinical trials comparing efavirenz and other active drugs currently recommended for treatment of HIV-infected, antiretroviral-naive patients. Electronic databases (Pubmed, Embase, the Cochrane Library, Trip Database) were searched up till 23 December 2013 for randomized controlled clinical trials published as a peer-reviewed papers, and concerning efavirenz-based regimens used as initial treatment for HIV infection. Thirty-four studies were included in the systematic review, while twenty-six trials were suitable for the meta-analysis. Efavirenz was compared with drugs from four different classes: NNRTIs other than efavirenz (nevirapine or rilpivirine), integrase strand transfer inhibitors (InSTIs), ritonavir-boosted protease inhibitors (bPI) and chemokine (C-C motif) receptor 5 (CCR5) antagonists (maraviroc), all of them were added to the background regimen. Results of the current meta-analysis showed that efavirenz-based regimens were equally effective as other recommended regimens based on NNRTI, ritonavir-boosted PI or CCR5 antagonist in terms of efficacy outcomes (disease progression and/or death, plasma viral HIV RNA <50 copies/ml) while statistically significant more patients treated with InSTI achieved plasma viral load <50 copies/ml at week 48. In comparison with both InSTI-based and CCR5-based therapy, efavirenz-based treatment was associated with a higher risk of therapy discontinuation due to adverse events. However, comparisons of efevirenz-based treatment with InSTI-based and CCR5-based therapy were based on a limited number of trials, therefore, conclusions from these two comparisons must be confirmed in further reliable randomized controlled studies. Results of our meta-analysis support the present clinical guidelines for antiretroviral-naive, HIV-infected patients, in which efavirenz is one of the most preferred regimens in the analyzed population. Beneficial safety profile of InSTI-based and CCR5-based therapy over efavirenz-based treatment needs further studies.

48-week efficacy and safety of dolutegravir relative to commonly used third agents in treatment-naive HIV-1-infected patients: a systematic review and network meta-analysis

BACKGROUND

A network meta-analysis can provide estimates of relative efficacy for treatments not directly studied in head-to-head randomized controlled trials. We estimated the relative efficacy and safety of dolutegravir (DTG) versus third agents currently recommended by guidelines, including ritonavir-boosted atazanavir (ATV/r), ritonavir-boosted darunavir (DRV/r), efavirenz (EFV), cobicistat-boosted elvitegravir (EVG/c), ritonavir-boosted lopinavir (LPV/r), raltegravir (RAL), and rilpivirine (RPV), in treatment-naive HIV-1-infected patients.

METHODS

A systematic review of published literature was conducted to identify phase 3/4 randomized controlled clinical trials (up to August 2013) including at least one third agent of interest in combination with a backbone nucleoside reverse transcriptase inhibitor (NRTI) regimen. Bayesian fixed-effect network meta-analysis models adjusting for the type of nucleoside reverse transcriptase inhibitor backbone (tenofovir disoproxil fumarate/emtricitabine [TDF/FTC] or abacavir/lamivudine [ABC/3TC]) were used to evaluate week 48 efficacy (HIV-RNA suppression to <50 copies/mL and change in CD4+ cells/µL) and safety (lipid changes, adverse events, and discontinuations due to adverse events) of DTG relative to all other treatments. Sensitivity analyses assessing the impact of NRTI treatment adjustment and random-effects models were performed.

RESULTS

Thirty-one studies including 17,000 patients were combined in the analysis. Adjusting for the effect of NRTI backbone, treatment with DTG resulted in significantly higher odds of virologic suppression (HIV RNA<50 copies/mL) and increase in CD4+ cells/µL versus ATV/r, DRV/r, EFV, LPV/r, and RPV. Dolutegravir had better or equivalent changes in total cholesterol, LDL, triglycerides, and lower odds of adverse events and discontinuation due to adverse events compared to all treatments. Random-effects and unadjusted models resulted in similar conclusions.

CONCLUSION

Three clinical trials of DTG have demonstrated comparable or superior efficacy and safety to DRV, RAL, and EFV in HIV-1-infected treatment-naive patients. This network meta-analysis suggests DTG is also favorable or comparable to other commonly used third agents (ATV/r, LPV/r, RPV, and EVG/c).

[GeSIDA/National AIDS Plan: Consensus document on antiretroviral therapy in adults infected by the human immunodeficiency virus (Updated January 2014)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients.

METHODS

To formulate these recommendations a panel composed of members of the Grupo de Estudio de Sida and the Plan Nacional sobre el Sida reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. Recommendations strength and the evidence in which they are supported are based on modified criteria of the Infectious Diseases Society of America.

RESULTS

In this update, antiretroviral therapy (ART) is recommended for all patients infected by type 1 human immunodeficiency virus (HIV-1). The strength and grade of the recommendation varies with the clinical circumstances: CDC stage B or C disease (A-I), asymptomatic patients (depending on the CD4+ T-lymphocyte count: <350cells/μL, A-I; 350-500 cells/μL, A-II, and >500 cells/μL, B-III), comorbid conditions (HIV nephropathy, chronic hepatitis caused by HBV or HCV, age >55years, high cardiovascular risk, neurocognitive disorders, and cancer, A-II), and prevention of transmission of HIV (mother-to-child or heterosexual, A-I; men who have sex with men, A-III). The objective of ART is to achieve an undetectable plasma viral load. Initial ART should always comprise a combination of 3 drugs, including 2 nucleoside reverse transcriptase inhibitors and a third drug from a different family (non-nucleoside reverse transcriptase inhibitor, protease inhibitor, or integrase inhibitor). Some of the possible initial regimens have been considered alternatives. This update presents the causes and criteria for switching ART in patients with undetectable plasma viral load and in cases of virological failure where rescue ART should comprise 2 or 3 drugs that are fully active against the virus. An update is also provided for the specific criteria for ART in special situations (acute infection, HIV-2 infection, and pregnancy) and with comorbid conditions (tuberculosis or other opportunistic infections, kidney disease, liver disease, and cancer).

CONCLUSIONS

These new guidelines updates previous recommendations related to cART (when to begin and what drugs should be used), how to monitor and what to do in case of viral failure or drug adverse reactions. cART specific criteria in comorbid patients and special situations are equally updated.

Recent trends in early stage response to combination antiretroviral therapy in Australia

BACKGROUND

There have been improvements in combination antiretroviral therapy (cART) over the past 15 years. The aim of this analysis was to assess whether improvements in ART have resulted in improvements in surrogates of HIV outcome.

METHODS

Patients in the Australian HIV Observational Database who initiated treatment using mono/duo therapy prior to 1996, or using cART from 1996 onwards, were included in the analysis. Patients were stratified by era of ART initiation. Median changes in CD4(+) T-cell count and the proportion of patients with detectable HIV viral load (>400 copies/ml) were calculated over the first 4 years of treatment. Probabilities of treatment switch were estimated using the Kaplan-Meier method.

RESULTS

A total of 2,753 patients were included in the analysis: 28% initiated treatment <1996 using mono/duo therapy and 72% initiated treatment ≥1996 using cART (30% 1996-1999, 12% 2000-2003, 11% 2004-2007 and 19% ≥2008). Overall CD4(+) T-cell count response improved by later era of initiation (P<0.001), although 2000-2003 CD4(+) T-cell count response was less than that for 1996-1999 (P=0.007). The average proportion with detectable viral load from 2 to 4 years post-treatment commencement by era was: <1996 mono/duo 0.69 (0.67-0.71), 1996-1999 cART 0.29 (0.28-0.30), 2000-2003 cART 0.22 (0.20-0.24), 2004-2007 cART 0.09 (0.07-0.10) and ≥2008 cART 0.04 (0.03-0.05). Probability of treatment switch at 4 years after initiation decreased from 53% in 1996-1999 to 29% after 2008 (P<0.001).

CONCLUSIONS

Across the five time-periods examined, there have been incremental improvements for patients initiated on cART, as measured by overall response (viral load and CD4(+) T-cell count) and also increased durability of first-line ART regimens.

Alzheimer's disease therapeutics targeted to the control of amyloid precursor protein translation: maintenance of brain iron homeostasis

The neurotoxicity of amyloid beta (Aβ), a major cleavage product of the amyloid precursor protein (APP), is enhanced by iron, as found in the amyloid plaques of Alzheimer's disease (AD) patients. By contrast, the long-known neuroprotective activity of APP is evident after α-secretase cleavage of the precursor to release sAPPα, and depends on the iron export actions of APP itself. The latter underlie its neurotrophic and protective effects in facilitating the homeostatic actions of ferroportin mediated-iron export. Thus APP-dependent iron export may alleviate oxidative stress by minimizing labile iron thus protecting neurons from iron overload during stroke and hemorrhage. Consistent with this, altered phosphorylation of iron-regulatory protein-1 (IRP1) and its signaling processes play a critical role in modulating APP translation via the 5' untranslated region (5'UTR) of its transcript. The APP 5'UTR region encodes a functional iron-responsive element (IRE) RNA stem loop that represents a potential target for modulating APP production. Targeted regulation of APP gene expression via the modulation of 5'UTR sequence function represents a novel approach for the potential treatment of AD since altering APP translation can be used to improve both the protective brain iron balance and provide anti-amyloid efficacy. Approved drugs including paroxetine and desferrioxamine and several novel compounds have been identified that suppress abnormal metal-promoted Aβ accumulation with a subset of these acting via APP 5'UTR-dependent mechanisms to modulate APP translation and cleavage to generate the non-toxic sAPPα.

A systematic review of a single-class maintenance strategy with nucleoside/nucleotide reverse transcriptase inhibitors in HIV/AIDS

BACKGROUND

Single-drug class regimens with nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) are generally not recommended as initial therapy because they are inferior compared with therapy with two NRTIs plus efavirenz. However, triple-NRTI combinations can be useful in specific circumstances such as in tuberculosis coinfection, pregnancy or dyslipidaemia. Here, we review the potential of such combinations to maintain viral suppression after induction of suppression by standard combination antiretroviral therapy (cART) and to evaluate the trade-off of NRTI-only regimens for metabolic control.

METHODS

We conducted a systematic search of the literature in two databases from 1 January 1998 up to 1 March 2013: Medline, through the search engine PubMed, and Embase.

RESULTS

A total of 11 randomized controlled trials (RCTs) with 2,105 patients and 3 observational studies with 2,639 patients were included. Studies including patients with mono- or dual-NRTI treatment before start of effective cART showed a tendency to higher failure rate because of resistance based on archived viral mutations. In studies with ART-naive subjects before start of cART, triple-NRTI combination showed virological activity comparable to two NRTIs plus a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor in all RCTs, but not in one cohort study. Switching improved serum lipids significantly.

CONCLUSIONS

Of the studied triple-NRTI combinations only abacavir/lamivudine/zidovudine was sufficiently potent. Triple-NRTI maintenance after successful induction with two-class cART appeared successful in treatment-naive subjects and remains a useful option in specific circumstances, especially when other drugs are not available or drug interactions are an issue.

Antiretroviral treatment interruption and loss to follow-up in two HIV cohorts in Australia and Asia: implications for 'test and treat' prevention strategy

Both antiretroviral treatment interruption (TI) and cessation have been strongly discouraged since 2006. We describe the incidence, duration, and risk factors for TI and loss-to-follow-up (LTFU) rates across 13 countries. All 4689 adults (76% men) in two large HIV cohorts in Australia and Asia commencing combination antiretroviral therapy (ART) to March 2010 were included. TI was defined by ART cessation >30 days, then recommencement, and loss to follow-up (LTFU) by no visit since 31 March 2009 and no record of death. Survival analysis and Poisson regression methods were used. With median follow-up of 4.4 years [interquartile range (IQR):2.1-6.5], TI incidence was 6.7 per 100 person years (PY) (95% CI:6.1-7.3) pre-2006, falling to 2.0 (95% CI:1.7-2.2) from 2006 (p<0.01). LTFU incidence was 3.5 per 100 PY (95% CI:3.1-3.9) pre-2006, and 4.1 (95% CI:3.5-4.9) from 2006 (p=0.22). TIs accounted for 6.4% of potential time on ART pre-2006 and 1.2% from 2006 (p<0.01), and LTFU 4.7% of potential time on ART pre-2006 and 6.6% from 2006 (p<0.01). Median TI duration was 163 (IQR: 75-391) days pre-2006 and 118 (IQR: 67-270) days from 2006 (p<0.01). Independent risk factors for the first TI were: Australia HIV Observational Database participation; ART initiation pre-2006; ART regimens including stavudine and didanosine; three nucleoside analogue reverse transcriptase inhibitors; ≥7 pills per day; and ART with food restrictions (fasting or with food). In conclusion, since 2006, 7.8% of patients had significant time off treatment, which has the potential to compromise any 'test and treat' policy as during the interruption viral load will rebound and increase the risk of transmission.

[Consensus Statement by GeSIDA/National AIDS Plan Secretariat on antiretroviral treatment in adults infected by the human immunodeficiency virus (Updated January 2013)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients.

METHODS

To formulate these recommendations a panel composed of members of the GeSIDA/National AIDS Plan Secretariat (Grupo de Estudio de Sida and the Secretaría del Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations and the evidence which support them are based on a modification of the criteria of Infectious Diseases Society of America.

RESULTS

cART is recommended in patients with symptoms of HIV infection, in pregnant women, in serodiscordant couples with high risk of transmission, in hepatitisB co-infection requiring treatment, and in HIV nephropathy. cART is recommended in asymptomatic patients if CD4 is <500cells/μl. If CD4 are >500cells/μl cART should be considered in the case of chronic hepatitisC, cirrhosis, high cardiovascular risk, plasma viral load >100.000 copies/ml, proportion of CD4 cells <14%, neurocognitive deficits, and in people aged >55years. The objective of cART is to achieve an undetectable viral load. The first cART should include 2 reverse transcriptase inhibitors (RTI) nucleoside analogs and a third drug (a non-analog RTI, a ritonavir boosted protease inhibitor, or an integrase inhibitor). The panel has consensually selected some drug combinations, for the first cART and specific criteria for cART in acute HIV infection, in tuberculosis and other HIV related opportunistic infections, for the women and in pregnancy, in hepatitisB or C co-infection, in HIV-2 infection, and in post-exposure prophylaxis.

CONCLUSIONS

These new guidelines update previous recommendations related to first cART (when to begin and what drugs should be used), how to monitor, and what to do in case of viral failure or adverse drug reactions. cART specific criteria in comorbid patients and special situations are similarly updated.

[Consensus document of Gesida and Spanish Secretariat for the National Plan on AIDS (SPNS) regarding combined antiretroviral treatment in adults infected by the human immunodeficiency virus (January 2012)]

This consensus document has been prepared by a panel consisting of members of the AIDS Study Group (Gesida) and the Spanish Secretariat for the National Plan on AIDS (SPNS) after reviewing the efficacy and safety results of clinical trials, cohort and pharmacokinetic studies published in medical journals, or presented in medical scientific meetings. Gesida has prepared an objective and structured method to prioritise combined antiretroviral treatment (cART) in naïve patients. Recommendations strength (A, B, C) and the evidence which supports them (I, II, III) are based on a modification of the Infectious Diseases Society of America criteria. The current antiretroviral treatment (ART) of choice for chronic HIV infection is the combination of three drugs. ART is recommended in patients with symptomatic HIV infection, in pregnancy, in serodiscordant couples with high transmission risk, hepatitis B fulfilling treatment criteria, and HIV nephropathy. Guidelines on ART treatment in patients with concurrent diagnosis of HIV infection and an opportunistic type C infection are included. In asymptomatic patients ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts <350 cells/μL; 2) when CD4 counts are between 350 and 500 cells/μL, therapy will be recommended and only delayed if patient is reluctant to take it, the CD4 are stabilised, and the plasma viral load is low; 3) therapy could be deferred when CD4 counts are above 500 cells/μL, but should be considered in cases of cirrhosis, chronic hepatitis C, high cardiovascular risk, plasma viral load >10(5) copies/mL, proportion of CD4 cells <14%, and in people aged >55 years. ART should include 2 reverse transcriptase inhibitors nucleoside analogues and a third drug (non-analogue reverse transcriptase inhibitor, ritonavir boosted protease inhibitor or integrase inhibitor). The panel has consensually selected and given priority to using the Gesida score for some drug combinations, some of them co-formulated. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures, but an undetectable viral load may be possible nowadays. Adverse events are a fading problem of ART. Guidelines in acute HIV infection, in women, in pregnancy, and to prevent mother-to-child transmission and pre- and post-exposition prophylaxis are commented upon. Management of hepatitis B or C co-infection, other co-morbidities, and the characteristics of ART in HIV-2 infection are included.

The impact of stigma on medication adherence among HIV-positive adolescent and young adult females and the moderating effects of coping and satisfaction with health care

To explore whether HIV stigma negatively impacts adherence to antiviral medications in HIV-infected adolescent women, moderational analysis was conducted and factors identified that could alter said relationship. Study participants were 178 adolescent females age 15-24, enrolled between 2003-2005, from 5 different cities and 60 provided adherence information. Findings reported by this cohort of 60 adolescent women included: medication adherence, 64.3% reporting adherence at baseline and 45.0% at 12 months; HIV stigma score of 57.60 (standard deviation [SD], 11.83; range, 25-86). HIV stigma was not found to be a significant predictor when binary logit regression was run with medication adherence at 1 year. Using moderational analysis, factors that could moderate stigma's effect on medication adherence was still pursued and identified the following to be significant at 12 months: health care satisfaction (B = -0.020, standard error [SE] = 0.010, p < .05); and Coping (proactive coping strategies [B = 0.012, SE = 0.005, p < .05]; turning to family [B = 0.012, SE = 0.016, p < 0.05]; spiritual coping [B = 0.021, SE = 0.010, p < 0.05]; professional help [B = 0.021, SE = 0.010, p < 0.05]; physical diversions [B = 0.016, SE = 0.007, p < 0.05]). Factors that had no significant moderating effects included: social support measures (mean = 74.9; median = 74.0) and depression score greater than 16 = 43%. We conclude that HIV-infected adolescent women experience HIV stigma and poor adherence over time. Factors like health care satisfaction and coping may minimize stigma's effect on medication adherence. Our findings are tempered by a small sample size and lack of a direct relationship between stigma and adherence on binary logit regression analysis.

A systematic review of the psychiatric side-effects of efavirenz

Concerns regarding the use of efavirenz in patients with a history of mental illness may predispose clinicians to not offer this agent to psychiatrically ill populations in spite of the convenience of once daily dosing, which can result in improved adherence in these at-risk populations. This systematic review examines the current data regarding the neuropsychiatric effects of efavirenz, and also attempts to provide guidance to clinicians using efavirenz to treat patients with mental illness. The review identified high rates of neuropsychiatric side effects including vivid dreams, insomnia and mood changes in approximately 50% of patients who initiate efavirenz. The effects begin quickly, commonly peak in the first 2 weeks, and are generally mild and transient in nature. Isolated case reports and uncontrolled data suggest higher rates of severe side effects; however, there is no clear evidence of a broadly increased risk of suicide or dangerous behavior for patients taking efavirenz as part of their antiretroviral regimen.

Atazanavir plus ritonavir or efavirenz as part of a 3-drug regimen for initial treatment of HIV-1

BACKGROUND

Limited data compare once-daily options for initial therapy for HIV-1.

OBJECTIVE

To compare time to virologic failure; first grade-3 or -4 sign, symptom, or laboratory abnormality (safety); and change or discontinuation of regimen (tolerability) for atazanavir plus ritonavir with efavirenz-containing initial therapy for HIV-1.

DESIGN

A randomized equivalence trial accrued from September 2005 to November 2007, with median follow-up of 138 weeks. Regimens were assigned by using a central computer, stratified by screening HIV-1 RNA level less than 100 000 copies/mL or 100 000 copies/mL or greater; blinding was known only to the site pharmacist. (ClinicalTrials.gov registration number: NCT00118898)

SETTING

59 AIDS Clinical Trials Group sites in the United States and Puerto Rico.

PATIENTS

Antiretroviral-naive patients.

INTERVENTION

Open-label atazanavir plus ritonavir or efavirenz, each given with with placebo-controlled abacavir-lamivudine or tenofovir disoproxil fumarate (DF)-emtricitabine.

MEASUREMENTS

Primary outcomes were time to virologic failure, safety, and tolerability events. Secondary end points included proportion of patients with HIV-1 RNA level less than 50 copies/mL, emergence of drug resistance, changes in CD4 cell counts, calculated creatinine clearance, and lipid levels.

RESULTS

463 eligible patients were randomly assigned to receive atazanavir plus ritonavir and 465 were assigned to receive efavirenz, both with abacavir-lamivudine; 322 (70%) and 324 (70%), respectively, completed follow-up. The respective numbers of participants in each group who received tenofovir DF-emtricitabine were 465 and 464; 342 (74%) and 343 (74%) completed follow-up. Primary efficacy was similar in the group that received atazanavir plus ritonavir and and the group that received efavirenz and did not differ according to whether abacavir-lamivudine or tenofovir DF-emtricitabine was also given. Hazard ratios for time to virologic failure were 1.13 (95% CI, 0.82 to 1.56) and 1.01 (CI, 0.70 to 1.46), respectively, although CIs did not meet prespecified criteria for equivalence. The time to safety (P = 0.048) and tolerability (P < 0.001) events was longer in persons given atazanavir plus ritonavir than in those given efavirenz with abacavir-lamivudine but not with tenofovir DF-emtricitabine.

LIMITATIONS

Neither HLA-B*5701 nor resistance testing was the standard of care when A5202 enrolled patients. The third drugs, atazanavir plus ritonavir and efavirenz, were open-label; the nucleoside reverse transcriptase inhibitors were prematurely unblinded in the high viral load stratum; and 32% of patients modified or discontinued treatment with their third drug.

CONCLUSION

Atazanavir plus ritonavir and efavirenz have similar antiviral activity when used with abacavir-lamivudine or tenofovir DF-emtricitabine.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Reverse transcriptase mutation K65N confers a decreased replication capacity to HIV-1 in comparison to K65R due to a decreased RT processivity

In addition to K65R, the other mutation observed at HIV-1 RT codon 65 is K65N. While K65N appears to have a phenotypic effect similar to K65R, it is less frequent during clinical trials. We compared the relative impact of K→N with respect to K→R change on viral replication capacity (RC). Mutant viruses were created and replication kinetics assays were performed in PBM cells. Analysis of RCs revealed a significant loss in replication (p=0.004) for viruses containing K65N mutation in comparison to those with K65R mutation. RT processivity assays showed a significant decrease in the processivity of K65N RT in comparison to K65R RT. We demonstrated that the significant decrease in RC of K65N viruses is related to the impaired RT processivity of K65N RT in comparison to K65R, and that the selection of the K65R mutation may be favored in clinical use of antiretroviral drugs compared to K65N.

[AIDS Study Group/Spanish AIDS Plan consensus document on antiretroviral therapy in adults with human immunodeficiency virus infection (updated January 2010)]

OBJECTIVE

This consensus document is an update of antiretroviral therapy recommendations for adult patients with human immunodeficiency virus infection.

METHODS

To formulate these recommendations a panel made up of members of the Grupo de Estudio de Sida (Gesida, AIDS Study Group) and the Plan Nacional sobre el Sida (PNS, Spanish AIDS Plan) reviewed the advances in the current understanding of the pathophysiology of human immunodeficiency virus (HIV) infection, the efficacy and safety of clinical trials, and cohort and pharmacokinetic studies published in biomedical journals or presented at scientific meetings. Three levels of evidence were defined according to the data source: randomized studies (level A), cohort or case-control studies (level B), and expert opinion (level C). The decision to recommend, consider or not to recommend ART was established in each situation.

RESULTS

Currently, the treatment of choice for chronic HIV infection is the combination of three drugs of two different classes, including 2 nucleosides or nucleotide analogs (NRTI) plus 1 non-nucleoside (NNRTI) or 1 boosted protease inhibitor (PI/r), but other combinations are possible. Initiation of ART is recommended in patients with symptomatic HIV infection. In asymptomatic patients, initiation of ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts below 350 cells/microl; 2) When CD4 counts are between 350 and 500 cells/microl, therapy should be started in case of cirrhosis, chronic hepatitis C, high cardiovascular risk, HIV nephropathy, HIV viral load above 100,000 copies/ml, proportion of CD4 cells under 14%, and in people aged over 55; 3) Therapy should be deferred when CD4 are above 500 cells/microl, but could be considered if any of previous considerations concurs. Treatment should be initiated in case of hepatitis B requiring treatment and should be considered for reduce sexual transmission. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures but undetectable viral loads maybe possible with the new drugs even in highly drug experienced patients. Genotype studies are useful in these situations. Drug toxicity of ART therapy is losing importance as benefits exceed adverse effects. Criteria for antiretroviral treatment in acute infection, pregnancy and post-exposure prophylaxis are mentioned as well as the management of HIV co-infection with hepatitis B or C.

CONCLUSIONS

CD4 cells counts, viral load and patient co-morbidities are the most important reference factors to consider when initiating ART in asymptomatic patients. The large number of available drugs, the increased sensitivity of tests to monitor viral load, and the ability to determine viral resistance is leading to a more individualized therapy approach in order to achieve undetectable viral load under any circumstances.

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

BACKGROUND

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

PURPOSE

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

METHODS

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

RESULTS

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

LIMITATIONS

Examples are restricted to HIV clinical trials.

CONCLUSIONS

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

Abacavir/lamivudine combination in the treatment of HIV: a review

Abacavir has been at the center of research and clinical interest in the last two years. The frequency of the associated abacavir hypersensitivity syndrome has decreased substantially since the introduction of routine testing for the HLA-B*5701 allele; the activity of the drug in HIV-infected persons with HIV RNA values more than 100,000 copies/mL has been questioned; the possible increased risk of myocardial infarction after recent exposure to abacavir has been debated; and the drug has been moved from the “recommended” category to the “alternative” category in several guidelines. Still, the drug remains a useful agent in combination with other drugs, including lamivudine, for the treatment of HIV infection. This review will focus on the pharmacokinetics, activity, side effects, and resistance profile of both abacavir and lamivudine, including a thorough review of all of the recent studies relevant to both drugs.

96-Week Efficacy and Safety of Atazanavir, With and Without Ritonavir, in a HAART Regimen in Treatment-Naive Patients

This study assesses virologic response, safety, tolerability, and changes in health-related quality of life (HRQoL) in antiretroviral (ARV)-naive patients treated with 2 atazanavir (ATV)-based regimens over 96 weeks. Treatment-naive adult patients (n = 200) were randomized to receive either ATV 300 mg with ritonavir (RTV) 100 mg (ATV300/r, n = 95) or ATV 400 mg (ATV400; n = 105). At week 96, 75% of ATV300/r-treated and 70% of ATV400-treated patients achieved viral loads <400 copies/mL (difference estimate [95% confidence interval, CI] = 5.1 [-7.1 to 17.2]). Five and 20 patients, respectively, experienced virologic failure. Adverse event-related discontinuations occurred among 8% receiving ATV300/r and 3% receiving ATV400. Plasma lipid elevations were generally low. Both regimens were well tolerated and associated with sustained improvements in HRQoL. These findings demonstrate long-term efficacy, tolerability, and safety of both ATV300/r and ATV400 in ARV-naive patients through 96 weeks with improvements in HRQoL.

Early versus delayed fixed dose combination abacavir/lamivudine/zidovudine in patients with HIV and tuberculosis in Tanzania

Fixed dose combination abacavir/lamivudine/zidovudine (ABC/3TC/ZDV) among HIV-1 and tuberculosis (TB)-coinfected patients was evaluated and outcomes between early vs. delayed initiation were compared. In a randomized, pilot study conducted in the Kilimanjaro Region of Tanzania, HIV-infected inpatients with smear-positive TB and total lymphocyte count <1200/mm(3) were randomized to initiate ABC/3TC/ZDV either 2 (early) or 8 (delayed) weeks after commencing antituberculosis therapy and were followed for 104 weeks. Of 94 patients screened, 70 enrolled (41% female, median CD4 count 103 cells/mm(3)), and 33 in each group completed 104 weeks. Two deaths and 12 serious adverse events (SAEs) were observed in the early arm vs. one death, one clinical failure, and seven SAEs in the delayed arm (p = 0.6012 for time to first grade 3/4 event, SAE, or death). CD4 cell increases were +331 and +328 cells/mm(3), respectively. TB-immune reconstitution inflammatory syndromes (TB-IRIS) were not observed in any subject. Using intent-to-treat (ITT), missing = failure analyses, 74% (26/35) vs. 89% (31/35) randomized to early vs. delayed therapy had HIV RNA levels <400 copies/ml at 104 weeks (p = 0.2182) and 66% (23/35) vs. 74% (26/35), respectively, had HIV RNA levels <50 copies/ml (p = 0.6026). In an analysis in which switches from ABC/3TC/ZDV = failure, those receiving early therapy were less likely to be suppressed to <400 copies/ml [60% (21/35) vs. 86% (30/35), p = 0.030]. TB-IRIS was not observed among the 70 coinfected subjects beginning antiretroviral treatment. ABC/3TC/ZDV was well tolerated and resulted in steady immunologic improvement. Rates of virologic suppression were similar between early and delayed treatment strategies with triple nucleoside regimens when substitutions were allowed.

Antiretroviral treatment of HIV infection: Swedish recommendations 2007

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

Abacavir/lamivudine fixed dose combination in the treatment of patients with HIV infection

HIV infection remains a common cause of morbidity and mortality worldwide. Fortunately, patients treated with combination antiretroviral therapy (ART) have significantly improved survival rates and quality of life. The standard of care for the treatment of ART-naive patients includes three drugs, two of which should be nucleoside reverse transcriptase inhibitors (NRTIs). Abacavir/lamivudine (ABC/3TC) is a fixed dose combination NRTI tablet that has been approved as an NRTI backbone. ABC/3TC is among the NRTI combinations that are recommended as first line in the most recent International AIDS Society–USA guidelines and WHO European Region protocol. However, owing to recently published data raising the possibility of an association between abacavir and heart disease, as well as data regarding efficacy in patients with higher HIV RNA levels, ABC/3TC has now been listed as an alternative NRTI backbone in the latest USA Department of Health and Human Services guidelines. While ABC has been associated with a hypersensitivity reaction that may be severe, a new test has been demonstrated to be effective in screening for the gene that is associated with this reaction.

Efavirenz--still first-line king?

BACKGROUND

Efavirenz is a potent, safe and tolerable non-nucleoside reverse transcriptase inhibitor (NNRTI) recommended as initial therapy. Recently, several new antiretroviral drugs, including second generation NNRTIs, protease-inhibitors, an integrase-inhibitor and a CCR5 inhibitor, have become or will be shortly available.

OBJECTIVE

This article will review relevant efficacy and safety data of efavirenz compared to these novel agents or certain common alternate drugs currently used as initial therapy in treatment-naive patients.

METHODS

Published articles and conference presentations pertaining to efavirenz and/or the newer antiretroviral agents were evaluated.

RESULTS/CONCLUSIONS

Efavirenz will continue to be preferred initial therapy for now. If longer-term studies of integrase inhibitors and second-generation NNRTIs confirm initial findings, they will eventually supplant efavirenz as preferred first-line agents.

[Clinical utility of atazanavir]

Atazanavir (ATV) is a protease inhibitor (PI) in which its main qualities, compared to other PI are dosing convenience, good tolerability and excellent metabolic profile. These characteristics makes it more like a nonnucleoside than a PI, but with the increased genetic barrier common to PI. It is indicated in initial treatment, simplification treatment or a change due to toxicity and in first line rescue treatment. The administering of ATV boosted with ritonavir (300/100 mg/d) has been approved in Europe in all clinical situations. In naïve patients it has been combined with practically all the nucleoside analogue pairs and has shown to be as effective as lopinavir/ritonavir and even efavirenz. In the USA, this indication has been approved for almost 5 years and ATV has become the most prescribed PI, while the EMEA has approved it this year. ATV is an optimal drug to replace other antiretrovirals in simplification strategies or changes due to toxicity. In several studies it has been shown that, in patients with good virological control, it can LPV/r or another PI, the therapeutic efficacy being maintained, with excellent tolerance and an improved lipid profile, and decreasing the cardiovascular risk. This strategy is widely used in Spain. In this scenario some patients could benefit from non-boosted ATV treatment (400 mg/d). ATV is an effective and very attractive option in first line rescue treatments in which the virus shows little or no resistance to PI, as its simplicity and tolerability can improve problems with compliance, the main cause of therapeutic failure. In patients with moderate resistance to PI, ATV is as effective as LPV/r. The survival of patients with HIV infection is increasingly longer and factors such as tolerability, cardiovascular risk and the adaptability of the treatment to the lifestyle of the patient, become more important, therefore ATV must play an important role in the treatment of HIV-infection.

Current and future antiretroviral treatment options in paediatric HIV infection

Because of a lack of prevention policies or problems in implementing prevention of mother-to-child transmission (P-MTCT), most of the 1500 daily new HIV infections in children aged<15 years are caused by MTCT. Fifteen percent of all HIV-infected individuals are children, but the vast majority lack access to highly active antiretroviral therapy (HAART), which can drastically reduce morbidity and mortality. There are 22 antiretroviral drugs currently approved by the US FDA for use in the treatment of HIV-infected adults and adolescents, but only 12 of these drugs are approved for use in children. Antiretroviral drugs belong to four major classes: nucleoside and nucleotide analogue reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors and fusion inhibitors. According to international guidelines developed by organizations including WHO, the Paediatric European Network for Treatment of AIDS (PENTA) and the US National Institutes of Health (US-NIH), the treatment of choice for HIV-infected children and adults is a combination of two NRTIs (backbone treatment) plus a third potent agent from a different class, either an NNRTI or a ritonavir-boosted protease inhibitor. There are specific challenges in treating HIV-infected children, including uncertainty about the best time to start treatment, the need for more paediatric formulations, the lack of pharmacokinetic studies for new drugs, and incomplete dosing guidelines. Furthermore, the most appropriate regimen for an individual child depends on a variety of factors, including the age of the child; the availability of appropriate drug formulations; the potency, complexity and toxicity of the drug regimen; the home situation; the child and caregiver's ability to adhere to the regimen; and the child's antiretroviral treatment history. In addition, antiretroviral drugs are not licensed for all age groups and the drugs are often not affordable. This review describes NNRTI and protease inhibitors as key components of first- and second-line antiretroviral therapy (ART), focusing on the rationale for choosing an NNRTI- versus protease inhibitor-based regimen based on the results of available phase II and III studies. Some of the new agents available for children as second-line and salvage therapy both on- and off-label are also discussed. The drug regimens described in this review are relevant to clinicians in developed and developing countries. The availability of new, potent compounds with different resistance and toxicity profiles may represent an alternative option to interclass switching and could redefine ART strategy, including the option of first-line NRTI-sparing regimens.

Determinants of Virological Failure after Successful Viral Load Suppression in First-Line Highly Active Antiretroviral Therapy

Background

We aimed to investigate the long-term virological outcomes of a cohort initially showing good responses to first-line highly active antiretroviral therapy (HAART) with no evidence of virological failure during the first year after achieving viral load (VL) undetectability (<50 copies/ml).

Methods

Virological failure was defined as a confirmed VL>400 copies/ml or a single VL>400 copies/ml followed by a treatment change or end of follow-up. Risk factors for low-level VL rebound (50–400 copies/ml) in the first year after achieving undetectability and for virological failure during subsequent follow-up were investigated by logistic and Poisson regression.

Results

In the first year after achieving VL undetectability, 354/1,386 (25.5%) patients experienced low-level VL rebound, the remaining patients maintained consistent undetectability. Low-level rebound occurred less commonly with non-nucleoside reverse transcriptase inhibitor (NNRTI)-based HAART than with other regimens ( P=0.01). Over median 2.2 (range 0.0–7.4) years of subsequent follow-up, 86 (6.2%) patients experienced virological failure, corresponding to 2.30 failures per 100 person-years (95% confidence interval [CI] 1.82–2.79). Independent predictors of virological failure included low-level rebound during the first year after achieving undetectability relative to consistent undetectability (rate ratio [RR] 2.18, 95% CI 1.15–4.10), female gender (RR 1.79, 95% CI 1.12–2.85) and receiving a ritonavir-boosted protease inhibitor (PI/r) relative to NNRTI-based HAART (RR 1.88, 95% CI 1.02–3.46).

Conclusions

Patients on first-line HAART who maintain consistent VL undetectability for 1 year have a low risk of subsequent virological failure. A subset might benefit from targeted interventions, including women and patients on PI/r-based HAART.

Clinical impact of patient population differences and genomic variation in efavirenz therapy

Guidelines for use of antiretroviral agents presently recommend first-line treatments with nonnucleoside reverse transcriptase inhibitor-based regimens. Efavirenz is the standard-of-care comparator for nonnucleoside reverse transcriptase inhibitor-based antiretroviral therapy. As with many antiretroviral medications, efavirenz is subject to interindividual variation in metabolism, effectiveness, and tolerability. Demographic factors such as age, sex, and ethnicity have been demonstrated to influence this variability, but other underlying factors such as genetics, disease state, and concomitant drug use can also play a role. The clinical impactions of these factors are only beginning to be understood. Although significant advances have led to a greater understanding of interactions between genetic and host factors that influence the efficacy and toxicity of efavirenz, providers should not withhold treatment of HIV infection with an efavirenz-based regimen on the basis of racial or ethic categorizations.

Short-term safety and tolerability of a once-daily fixed-dose abacavir-lamivudine combination versus twice-daily dosing of abacavir and lamivudine as separate components: findings from the ALOHA study

STUDY OBJECTIVE

To evaluate the short-term (12 wks) safety and tolerability of a once-daily, fixed-dose abacavir-lamivudine combination versus twice-daily dosing of the separate components, both with background antiretroviral therapy.

DESIGN

Phase IIIB, randomized, open-label, parallel-group, multicenter study.

SETTING

One hundred forty-six human immunodeficiency virus (HIV) clinics.

PATIENTS

Six hundred eighty antiretroviral therapy-naïve patients with HIV type 1 RNA greater than 1000 copies/ml at baseline.

INTERVENTION

Patients were randomly assigned in a 2:1 manner to receive either abacavir 600 mg-lamivudine 300 mg once/day or abacavir 300 mg twice/day and lamivudine 150 mg twice/day. Subjects were stratified based on choice of third or fourth antiretroviral drug (nucleoside reverse transcriptase inhibitor [NRTI], NNRTI, or protease inhibitor), assigned before randomization.

MEASUREMENTS AND MAIN RESULTS

The primary end point was occurrence of grades 2-4 adverse events and serious adverse events; abacavir hypersensitivity reactions were considered serious adverse events. Baseline characteristics were similar between the once-daily (455 patients) and twice-daily (225 patients) groups. The rates of all grades 2-4 adverse events were similar: once-daily 33% (150 patients), twice-daily 31% (69). A slightly larger proportion of patients in the twice-daily group experienced drug-related grades 2-4 adverse events: once-daily 10% (47), twice-daily 16% (36). Rates of all serious adverse events (once-daily 11% [49], twice-daily 10% [22]) and drug-related serious adverse events (once-daily 5% [21], twice-daily 8% [17]) were similar. The rate of suspected abacavir hypersensitivity reaction was 5.3% (once-daily 4.4% [20], twice-daily 7.1% [16]), with a higher rate for the NNRTI stratum of the twice-daily group (8.6% [10]) than in any other stratum (once-daily, NNRTI 4.3% [10]; twice-daily, protease inhibitor 5.6% [6]; once-daily, protease inhibitor 4.6% [10]).

CONCLUSION

In the short-term, the rates of adverse events in the once-daily and twice-daily groups appeared to be similar. The rate of suspected abacavir hypersensitivity reaction in the once-daily group was lower than the rate in the twice-daily group.

Antiretroviral therapy : optimal sequencing of therapy to avoid resistance

In the second decade of highly active antiretroviral therapy, drug regimens offer more potent, less toxic and more durable choices. However, strategies addressing convenient sequential use of active antiretroviral combinations are rarely presented in the literature. Studies have seldom directly addressed this issue, despite it being a matter of daily use in clinical practice. This is, in part, because of the complexity of HIV-1 resistance information as well as the complexity of designing these types of studies. Nevertheless, several principles can effectively assist the planning of antiretroviral drug sequencing. The introduction of tenofovir disoproxil fumarate, abacavir and emtricitabine into current nucleoside backbone options, with each of them selecting for an individual pattern of resistance mutations, now permits sequencing in the context of previously popular thymidine analogues (zidovudine and stavudine). Similarly, newer ritonavir-boosted protease inhibitors could potentially be sequenced in a manner that uses the least cross-resistance prone protease inhibitor at the start of therapy, while leaving the most cross-resistance prone drugs for later, as long as there is rationale to employ such a compound because of its utility against commonly observed drug-resistant forms of HIV-1.

Comparative efficacy of nucleoside/nucleotide reverse transcriptase inhibitors in combination with efavirenz: results of a systematic overview

BACKGROUND

Many trials of antiretroviral therapy in treatment-naïve subjects have investigated the relative efficacy of the third drug in a treatment regimen. However, the nucleoside/nucleotide reverse transcriptase inhibitor (NRTI) components may also affect efficacy.

METHOD

A systematic overview of clinical trials studying initial treatment in naïve subjects receiving efavirenz-containing regimens and providing week 48 time to loss of virologic response (TLOVR) results was undertaken to compare results with different NRTI combinations.

RESULTS

Seven trials studying 3,807 subjects were identified that met the inclusion criteria. Baseline characteristics were similar across studies. Using the week 48 TLOVR results as the primary method of comparison, combinations of tenofovir and lamivudine or emtricitabine appeared to provide improved virologic responses. Similar results were obtained when the proportions of subjects with plasma HIV RNA levels <50 copies/mL were examined.

Long-term observation of adolescents initiating HAART therapy: three-year follow-up

The PACTG 381 cohort included 120 adolescents infected via high-risk behaviors and treated with at least two NRTIs plus either a protease inhibitor or an efavirenz-containing HAART regimen. After 24 weeks of therapy, only 69 of 118 (59%) evaluable subjects had undetectable viral loads. We now present findings of the study after 3 years of follow-up. Virologic, immunologic, and treatment information were collected from subjects every 12 weeks beyond the first 24 weeks of therapy through 156 weeks. Of the 120 subjects starting HAART, 44 (37%) stayed on study treatment for the 3 years of observation. Twenty-nine (24%) subjects reached and maintained undetectable viral loads. Poorer adherence (p = 0.016), higher baseline viral load (p = 0.010), and CD8 naive counts (p = 0.034) predicted virologic failure. Immunologic measurements improved from entry to the end of follow-up in the subjects with undetectable viral loads. CD4 counts at the end of study were not significantly different from HIV-uninfected youth, but CD4%, CD8 counts and percent, and CD8 activation markers remained significantly different. Adolescents infected with HIV via high-risk behaviors have less than optimal responses to HAART therapy with only 24% achieving and maintaining undetectable viral loads over 3 years. Immunologic improvement was demonstrated and CD4 counts in subjects with virologic control reached levels in HIV-uninfected adolescents. Interventions, especially those focused on adherence, are necessary to improve HAART outcomes in adolescents.

Nucleoside and nucleotide reverse transcriptase inhibitors in children

By the end of 2006, approximately 2.3 million children worldwide were living with HIV infection, representing about 15% of all HIV-infected individuals but only 5-7% of the total population of treated patients worldwide. Despite a general increase in the use of antiretroviral therapy (ART) in resource-limited settings, appropriate care and ART remain inaccessible for most of the world's HIV-infected children. ART of children is challenging because of a general lack of paediatric formulations (including tablets in paediatric strengths), limited options of drugs available for children (some have been approved only for use in adults), different viral and immunological responses, dependency on caregivers for administration of the therapy, and specific issues of toxicity in long-term therapy related to maturation and development. As in adults, nucleoside reverse transcriptase inhibitors (NRTIs) are a key component of any ART schedule in children, being the recommended 'backbone' treatment in US, European and WHO guidelines, and, indeed, NRTIs have been extensively studied in children. NRTIs are the class of antiretroviral drugs that have more drugs licensed for paediatric use and more paediatric formulations.Generally, the dual NRTI backbone treatment of combination with a non-NRTI (NNRTI) or protease inhibitor (PI) should comprise a cytidine analogue (lamivudine, emtricitabine) and a thymidine analogue (stavudine, zidovudine), guanosine analogue (i.e. abacavir), or nucleotide RTI (NtRTI; i.e. tenofovir). European and US guidelines recommend the use of triple NRTI therapy (abacavir/lamivudine/zidovudine) in children with anticipated poor adherence to other treatment regimens because of tablet burden. In conclusion, while use of ART in children needs to be dramatically increased, selecting and administering the best drug combination for children is still limited by a lack of paediatric formulations and knowledge of drug metabolism, safety and efficacy in children. NRTIs are already a key component of paediatric ART, but fixed-dose combinations and specific research in children are needed to optimise their use. In this article we review the available information to facilitate selection of the best NRTI for backbone treatment in combination ART for HIV-infected children.

Strategies for the optimal sequencing of antiretroviral drugs toward overcoming and preventing drug resistance

Drug regimens now offer more potent, less toxic and more durable choices in the treatment of HIV disease than ever before. This has led to a need to consider the convenient, sequential use of active antiretroviral combinations. Ritonavir-boosted protease inhibitors (PIs) can now be potentially sequenced in a manner that uses the least cross-resistance-prone PI at the start of therapy while leaving the most cross-resistance-prone drug for later, if the latter retains activity against commonly observed drug-resistant forms. Similarly, such new drugs as tenofovir, abacavir and emtricitabine, which make up current nucleoside backbone options, can be potentially sequenced, since each of them selects for an individual pattern of resistance mutations that are generally distinct from those selected by previously popular thymidine analogs such as zidovudine and stavudine.

Antiretroviral management of treatment-naive patients

Antiretroviral management of treatment-naive patients begins with the decision of when to start treatment. Current treatment guidelines suggest starting therapy in anyone with AIDS, HIV-related symptoms, or a CD4 cell count less than 200/mm3 regardless of symptoms. Starting treatment in asymptomatic patients with CD4 of more than 200 requires consideration of a number of pros and cons, and individualization is the key. Recommended first-line antiretroviral regimens consist of two nucleoside reverse transcriptase inhibitors together with either a nonnucleoside reverse transcriptase inhibitor or a protease inhibitor (with or without ritonavir boosting). The goal of antiretroviral therapy is maximally to suppress viremia, enhance or improve immune function, and prevent clinical progression.

Reaching undetectable viral loads after initial HIV treatment

An HIV patient’s chance for long-term treatment success is maximized when their first-line regimen produces an undetectable viral load. A persistently detectable viral load leads to the development of resistance and subsequent immunological and virological failure. It is important to select a regimen with excellent efficacy, tolerability and toxicity profile that is also easy to administer. Tenofovir/emtricitabine provides an effective and well-tolerated nucleoside analog reverse transcriptase inhibitor (NRTI) combination. Regimens with ritonavir-boosted protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors are superior to ritonavir-unboosted PIs and NRTIs in reducing viral load. Data suggest that regimens with lopinavir/ritonavir or efavirenz have the best long-term chance of producing an undetectable viral load.