A randomized study of emtricitabine and lamivudine in stably suppressed patients with HIV

Antiretroviral therapy resistance mutations among HIV infected people in Kazakhstan

In Kazakhstan, the number of people living with HIV (PLHIV) has increased steadily by 39% since 2010. Development of antiretroviral therapy (ART) resistance mutations (ARTRM) is a major hurdle in achieving effective treatment and prevention against HIV. Using HIV pol sequences from 602 PLHIV from Kazakhstan, we analyzed ARTRMs for their association with factors that may promote development of ARTRMs. 56% PLHIV were infected with HIV subtype A6 and 42% with CRF02_AG. The ARTRM Q174K was associated with increased viral load and decreased CD4+ cell count, while infection with CRF02_AG was associated with a lower likelihood of Q174K. Interestingly, CRF02_AG was positively associated with the ARTRM L10V that, in turn, was observed frequently with darunavir administration. Infection with CRF02_AG was positively associated with the ARTRM S162A that, in turn, was frequently observed with the administration of nevirapine, also associated with lower CD4 counts. Zidovudine or Nevirapine receipt was associated with the development of the ARTRM E138A, that, in turn, was associated with lower CD4 counts. Determination of a patient's HIV variant can help guide ART choice in Kazakhstan. For example, PLHIV infected with CRF02_AG will benefit less from darunavir and nevirapine, and emtricitabine should replace zidovudine.

HIV-related cardiovascular diseases: the search for a unifying hypothesis

Although the extensive rollout of antiretroviral (ARV) therapy resulted in a longer life expectancy for people living with human immunodeficiency virus (PLHIV), such individuals display a relatively increased occurrence of cardiovascular diseases (CVD). This health challenge stimulated significant research interests in the field, leading to an improved understanding of both lifestyle-related risk factors and the underlying mechanisms of CVD onset in PLHIV. However, despite such progress, the precise role of various risk factors and mechanisms underlying the development of HIV-mediated CVD still remains relatively poorly understood. Therefore, we review CVD onset in PLHIV and focus on 1) the spectrum of cardiovascular complications that typically manifest in such persons and 2) underlying mechanisms that are implicated in this process. Here, the contributions of such factors and modulators and underlying mechanisms are considered in a holistic and integrative manner to generate a unifying hypothesis that includes identification of the core pathways mediating CVD onset. The review focuses on the sub-Saharan African context, as there are relatively high numbers of PLHIV residing within this region, indicating that the greater CVD risk will increasingly threaten the well-being and health of its citizens. It is our opinion that such an approach helps point the way for future research efforts to improve treatment strategies and/or lifestyle-related modifications for PLHIV.

Twenty-Five Years of Lamivudine: Current and Future Use for the Treatment of HIV-1 Infection

Supplemental Digital Content is Available in the Text.

Innovation in medicine is a dynamic, complex, and continuous process that cannot be isolated to a single moment in time. Anniversaries offer opportunities to commemorate crucial discoveries of modern medicine, such as penicillin (1928), polio vaccination (inactivated, 1955; oral, 1961), the surface antigen of the hepatitis B virus (1967), monoclonal antibodies (1975), and the first HIV antiretroviral drugs (zidovudine, 1987). The advent of antiretroviral drugs has had a profound effect on the progress of the epidemiology of HIV infection, transforming a terminal, irreversible disease that caused a global health crisis into a treatable but chronic disease. This result has been driven by the success of antiretroviral drug combinations that include nucleoside reverse transcriptase inhibitors such as lamivudine. Lamivudine, an L-enantiomeric analog of cytosine, potently affects HIV replication by inhibiting viral reverse transcriptase enzymes at concentrations without toxicity against human polymerases. Although lamivudine was approved more than 2 decades ago, it remains a key component of first-line therapy for HIV because of its virological efficacy and ability to be partnered with other antiretroviral agents in traditional and novel combination therapies. The prominence of lamivudine in HIV therapy is highlighted by its incorporation in recent innovative treatment strategies, such as single-tablet regimens that address challenges associated with regimen complexity and treatment adherence and 2-drug regimens being developed to mitigate cumulative drug exposure and toxicities. This review summarizes how the pharmacologic and virologic properties of lamivudine have solidified its role in contemporary HIV therapy and continue to support its use in emerging therapies.

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.

Candidates for inclusion in a universal antiretroviral regimen: are lamivudine and emtricitabine interchangeable?

PURPOSE OF REVIEW

Lamivudine (3TC) and emtricitabine (FTC) are the most widely used antiretroviral medications worldwide and are considered by the WHO to be interchangeable. This article reviews evidence supporting interchangeability of 3TC and FTC and considerations for future use.

RECENT FINDINGS

Three randomized trials have directly compared the safety and efficacy of 3TC and FTC against identical backbone regimens. Each of these trials reported a nonsignificant difference in virological suppression, and when results were pooled the overall difference was nonsignificant (relative risk 1.03, 95% confidence interval 0.96-1.10). These findings of equivalence are further supported by indirect evidence from nine randomized trials comparing 3TC and FTC against a similar backbone regimen of two different nucleoside reverse transcriptase inhibitors (relative risk of virological suppression 0.99, 95% confidence interval 0.96-1.01). Data from observational studies is mixed. Overall, reported differences between 3TC and FTC in observational studies are often associated with differences in the baseline characteristics of the treatment groups, notably with respect to immunological and virological status, comorbidity, substance misuse, and pill burden.

SUMMARY

The totality of evidence to date, from pharmacological data to observational studies to direct and indirect comparisons in randomized trials, suggests that 3TC and FTC can be considered to be therapeutically interchangeable and that if there are any differences, these are likely to be very small and not of major clinical importance.

Interventions for Neurocognitive Dysfunction

PURPOSE OF REVIEW

This study aimed to evaluate current barriers to HIV cure strategies and interventions for neurocognitive dysfunction with a particular focus on recent advancements over the last 3 years.

RECENT FINDINGS

Optimal anti-retroviral therapy (ART) poses challenges to minimise neurotoxicity, whilst ensuring blood-brain barrier penetration and minimising the risk of cerebrovascular disease. CSF biomarkers, BCL11B and neurofilament light chain may be implicated with a neuroinflammatory cascade leading to cognitive impairment. Diagnostic imaging with diffusion tensor imaging and resting-state fMRI show promise in future diagnosis and monitoring of HAND. The introduction of ART has resulted in a dramatic decline in HIV-associated dementia. Despite this reduction, milder forms of HIV-associated neurocognitive disorder (HAND) are still prevalent and are clinically significant. The central nervous system (CNS) has been recognised as a probable reservoir and sanctuary for HIV, representing a significant barrier to management interventions.

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.

Lamivudine-Induced Skin Rash Remains an Underdiagnosed Entity in HIV: A Case Series from a Single Center

BACKGROUND

Hypersensitivity reaction to antiretroviral treatment (ART) poses potential threats in maintenance of treatment. Lamivudine (3TC), is rare to cause rash. We are reporting 23 cases of 3TC-induced rash.

METHODS

An observational study conducted in the antiretroviral treatment center of a tertiary care hospital of North India from Feb 2009-Dec 2013 to record 3TC-induced rash. These were then recommended to start ART without 3TC and were followed up at 1-, 2-, and at 4-week intervals to monitor the toxicity, if any, with alternate therapy.

RESULTS

We observed 3TC-induced skin rash in 23 HIV-infected individuals (0.7%), out of 3213 HIV-infected individuals initiated on first line ART (zidovudine [ZDV]/tenofovir [TDF] + 3TC +nevirapine [NVP]/efavirenz [EFV] during the study period of 5 years [Feb 2009-Dec 2013]). The mean age of these 23 individuals was 37.5 ± 12.8 (17-60) years. Lamivudine rash was more common in women than men (F = 19, M = 4), with an overall mean age of 37.5 ± 12.8 (17-60) years. It was generalized, erythematous, maculopapular eruptions associated with intense itching with no associated mucosal involvement. Lamivudine was substituted with TDF in 19, didanosine (ddl) in 3 and abacavir (ABC) in 1 individual. Mean duration of follow-up is 11.1 ± 12.8 (3-42) months. CD4 count was repeated at 3 months and showed significant improvement (P = 0.002).

CONCLUSION

Lamivudine-induced rash was found at a frequency of 0.7%. The correct and early recognition that the rash is due to 3TC, would save unnecessary substitution to a different class of drugs.

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.

Effectiveness of antiretroviral therapy in individuals who for economic reasons were switched from a once-daily single-tablet regimen to a triple-tablet regimen

BACKGROUND

To assess the impact on virological outcomes of a switch from branded single-tablet regimen (STR) including tenofovir, efavirenz, and emtricitabine (STR-TEE) to generic triple-tablet regimen (TTR), including tenofovir, efavirenz, and lamivudine (TTR-TEL), which was implemented on April 1, 2011 to obtain economic savings.

METHODS AND FINDINGS

From the Capital Region of Denmark (covering two-thirds of the Danish HIV patients), we included combination antiretroviral therapy (cART)-naive patients who administered STR-TEE from April 1, 2010 to March 31, 2011 (n = 111) or TTR-TEL from April 1, 2011 to March 31, 2012 (n = 56) and cART-experienced HIV patients who were on STR-TEE from April 1, 2010 (n = 356) or were switched from STR-TEE to TTR-TEL after April 1, 2011 (n = 512). We estimated the fraction with detectable HIV-RNA, development of the 184V/I resistance mutations, and time to switch of cART. Approximately 96.2% of cART-experienced patients on STR-TEE were shifted to TTR-TEL after April 1, 2011. For the naive STR-TEE and TTR-TEL patients, the fractions with detectable HIV-RNA at week 48 were 7.0% and 8.3% and for the cART experienced 4.0% and 4.4%, respectively. The 184V/I resistance mutation was detected in 1 cART-experienced patient on TTR-TEL with virological failure. The risk of switch to a new cART regimen was slightly increased in the cART-experienced population (difference in 1-year risk: 1.5%; 95% confidence interval: -2.4% to 5.4%).

CONCLUSIONS

In settings comparable with the Danish health care system, the estimated economic savings from a switch from STR-TEE to TTR-TEL can be realized with negligible short-term risk of adverse outcomes.

Lower pill burden and once-daily antiretroviral treatment regimens for HIV infection: A meta-analysis of randomized controlled trials

Once-daily compared with twice-daily antiretroviral therapy regimens increased adherence; however, the difference was modest and not associated with a difference in virological suppression. In addition, higher pill burden was associated with lower rates of virological suppression, whether once- or twice-daily regimens.

Background. Contemporary antiretroviral treatment regimens are simpler than in the past, with lower pill burden and once-daily dosing frequency common. We performed a meta-analysis of randomized controlled trials (RCTs) to investigate the impact of pill burden and once-daily vs twice-daily dosing on ART adherence and virological outcomes.

Methods. A literature search of 4 electronic databases through 31 March 2013 was used. RCTs comparing once-daily vs twice-daily ART regimens that also reported on adherence and virological suppression were included. Study design, study population characteristics, intervention, outcome measures, and study quality were extracted. Study quality was rated using the Cochrane risk-of-bias tool.

Results. Nineteen studies met our inclusion criteria (N = 6312 adult patients). Higher pill burden was associated with both lower adherence rates (P = .004) and worse virological suppression (P < .0001) in both once-daily and twice-daily subgroups, although the association with adherence in the once-daily subgroup was not statistically significant. The average adherence was modestly higher in once-daily regimens than twice-daily regimens (weighted mean difference = 2.55%; 95% confidence interval [CI], 1.23 to 3.87; P = .0002). Patients on once-daily regimens did not achieve virological suppression more frequently than patients on twice-daily regimens (relative risk [RR] = 1.01; 95% CI, 0.99 to 1.03; P = .50). Both adherence and viral load suppression decreased over time, but adherence decreased less with once-daily dosing than with twice-daily dosing.

Conclusions. Lower pill burden was associated with both better adherence and virological suppression. Adherence, but not virological suppression, was slightly better with once- vs twice-daily regimens.

Comparative efficacy of Lamivudine and emtricitabine: a systematic review and meta-analysis of randomized trials

Introduction

Lamivudine and emtricitabine are considered equivalent by several guidelines, but evidence of comparable efficacy is conflicting.

Methods

We searched two databases up to June 30 2013 to identify randomized and quasi-randomized trials in which lamivudine and emtricitabine were used as part of combination antiretroviral therapy for treatment-naïve or experienced HIV-positive adult patients. We only included trials where partner drugs in the regimen were identical or could be considered to be comparable. We allowed for comparisons between tenofovir and abacavir provided the study population did not begin treatment with a viral load >100,000 copies/ml.

Results

12 trials contributed 15 different randomized comparisons providing data on 2251 patients receiving lamivudine and 2662 patients receiving emtricitabine. Treatment success was not significantly different in any of the 12 trials. In the three trials that directly compared lamivudine and emtricitabine, the relative risk for achieving treatment success was non-significant (RR 1.03 95%CI 0.96-1.10). For all trials combined, the pooled relative risk for treatment success was not significantly different (RR 1.00, 95%CI 0.97–1.02). No heterogeneity was observed (I² = 0). Similarly, there was no difference in the pooled relative risk for treatment failure (RR 1.08, 95%CI 0.94–1.22, I² = 3.4%).

Conclusions

The findings of this systematic review suggest that lamivudine and emtricitabine are clinically equivalent.

Deficient reporting and interpretation of non-inferiority randomized clinical trials in HIV patients: a systematic review

OBJECTIVES

Non-inferiority (NI) randomized clinical trials (RCTs) commonly evaluate efficacy of new antiretroviral (ARV) drugs in human immunodeficiency virus (HIV) patients. Their reporting and interpretation have not been systematically evaluated. We evaluated the reporting of NI RCTs in HIV patients according to the CONSORT statement and assessed the degree of misinterpretation of RCTs when NI was inconclusive or not established.

DESIGN

Systematic review.

METHODS

PubMed, Web of Science, and Scopus were reviewed until December 2011. Selection and extraction was performed independently by three reviewers.

RESULTS

Of the 42 RCTs (n = 21,919; range 41-3,316) selected, 23 were in ARV-naïve and 19 in ARV-experienced patients. Twenty-seven (64%) RCTs provided information about prior RCTs of the active comparator, and 37 (88%) used 2-sided CIs. Two thirds of trials used a NI margin between 10 and 12%, although only 12 explained the method to determine it. Blinding was used in 9 studies only. The main conclusion was based on both intention-to-treat (ITT) and per protocol (PP) analyses in 5 trials, on PP analysis only in 4 studies, and on ITT only in 31 studies. Eleven of 16 studies with NI inconclusive or not established highlighted NI or equivalence, and distracted readers with positive secondary results.

CONCLUSIONS

There is poor reporting and interpretation of NI RCTs performed in HIV patients. Maximizing the reporting of the method of NI margin determination, use of blinding and both ITT and PP analyses, and interpreting negative NI according to actual primary findings will improve the understanding of results and their translation into clinical practice.

Use of Filgrastim (r-metHuG-CSF) in Human Immunodeficiency Virus Infection

In 2008, an estimated 33.4 million individuals worldwide were infected with the human immunodeficiency virus (HIV) [1]. Only a few years ago, infection with HIV almost invariably culminated in the development of the acquired immunodeficiency syndrome (AIDS), characterized by severe depletion of CD4⁺ lymphocytes leading to derangements predominantly affecting cell-mediated immunity, but affecting humoral immunity as well [2]. In the later stages of AIDS, neutropenia and neutrophil functional deficits were common sequelae of HIV infection, other opportunistic infections, or HIV- or opportunistic infection-related treatment [3]. The care of the HIV-infected patient was palliative in nature, and the possibility that use of filgrastim (rHuG-CSF) might extend survival in late-stage AIDS patients with severe neutropenia or severe opportunistic infections, or might be a treatment for HIV infection itself, was explored [4]. Subsequently, however, the development of protease inhibitors and the widespread adoption of their use in multidrug regimens of highly active antiretroviral therapy (HAART) revolutionized the care of HIV-infected patients, and the number of patients dying from HIV decreased dramatically [5].

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

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

Investigation of emtricitabine-associated skin pigmentation and safety in HIV-1-infected Japanese patients

Emtricitabine (FTC) has been reported to cause skin pigmentation (SP), and the incidence of SP associated with FTC varied with ethnicity, with a higher rate in African-American patients (8%). We assessed the incidence of SP in Japanese HIV-1-infected patients receiving combination antiretroviral therapy (cART) with FTC for a period of 48 weeks and confirmed new findings of FTC-associated SP, including pathological characteristics. This was a multicenter, prospective, longitudinal non-randomized study. We evaluated the appearance of SP at 48 weeks as the primary endpoint in 155 Japanese patients, and secondary endpoints included the characteristics of the SP (location, color tone, size, and progression). Six cases (3.9%) of SP occurred at a median of 124 days (range: 7-259 days) within 48 weeks. The SP looked like an isolated dark spot, 1-2 mm in diameter, mainly on the hands and/or feet. The severity of all the SPs was mild. Each SP had disappeared or faded at a median of 112 days (range: 28-315 days) with continued FTC. FTC-associated SP was considered to be lentigo simplex by dermatoscopy and pathological appearance. In summary, the incidence of FTC-associated SP in Japanese patients was 3.9%, and was comparable to the previously reported incidence in Asian patients (4%). FTC-associated SP was not associated with any clinically significant symptoms and has little clinical significance.

One-pill once-a-day HAART: a simplification strategy that improves adherence and quality of life of HIV-infected subjects

OBJECTIVE

The aim of the ADONE (ADherence to ONE pill) study was to verify the effect of a reduced number of pills on adherence and quality of life (QoL) in HIV-infected patients on highly active antiretroviral therapy (HAART).

DESIGN

Prospective, multicenter, study.

METHODS

Patients chronically treated with emtricitabine (FTC) + tenofovir (TDF) + efavirenz (EFV) or lamivudine (3TC) +TDF +EFV and with a HIV-RNA < 50 copies/mL were switched to the single-pill fixed-dose regimen (FDR) of FTC +TDF +EFV. Data were collected with SF-36 using visual analog scales. Results of the final (6 months) primary as-treated analysis are reported.

RESULTS

212 patients (77.4% males) of mean age 45.8 years were enrolled; 202 completed the study. One month post switch to FDR the adherence rate increased significantly to 96.1% from a baseline value of 93.8% (P < 0.01). The increase was steadily maintained throughout the study (96.2% at 6 months). QoL improved over time from 68.8% to 72.7% (P = 0.042) as well, and was significantly associated with the perception of health status, presence of adverse events (AEs) and number of reported AEs (P < 0.0001). QoL significantly influenced adherence (P < 0.0001). During FDR use the mean CD4 count increased from 556 to 605 cells/muL (P < 0.0001). At the end of follow-up 98% of patients maintained HIV-RNA level < 50 copies/mL and 100% <400 copies/mL. Four patients stopped therapy because they were lost to follow-up and 6 because of AEs (insomnia/nervousness 4, allergy 1, difficulties swallowing pills 1).

CONCLUSION

By substituting a one-pill once-a-day HAART, we observed an improvement of both adherence and QoL while maintaining high virologic and immunologic efficacy. HAART simplicity is an added value that favors adherence and may improve long-term success.

Emerging mutations at virological failure of HAART combinations containing tenofovir and lamivudine or emtricitabine

OBJECTIVE

To compare the emergence of drug-resistant HIV variants at failure of lamivudine (3TC)/tenofovir (TDF)-containing or emtricitabine (FTC)/TDF-containing HAART as a consequence of the different 3TC and FTC intracellular half-lives.

DESIGN

Retrospective evaluation of 859 patients selected from an Italian HIV resistance database (Antiretroviral Resistance Cohort Analysis).

METHODS

Patients were selected for analysis if treated with a HAART whose nucleoside/nucleotide reverse transcriptase inhibitor backbone was either 3TC/TDF or FTC/TDF; if they experienced a virological failure after at least 6 months of plasma HIV-RNA undetectability; and if HIV genotypes before treatment and at failure were available. Univariate and multivariate logistic regression analyses were done to detect predictors of resistance mutations emerging at failure.

RESULTS

Of 714 patients failing with 3TC/TDF and 145 with FTC/TDF, 35.8 and 21.1% were in Centers for Disease Control and Prevention stage C, and 8.8 and 15.2% were on first-line HAART, respectively. At multivariate analysis, the emergence of K70R (P = 0.002), M184V (P = 0.031), T215F (P = 0.020) and Y181C (P = 0.005) was significantly more common in 3TC-treated than in FTC-treated patients, with an odds ratio of 4, 1.56, 1.89 and 3.84, respectively.

CONCLUSION

Despite their close structural similarity, 3TC and FTC are associated with a significantly different rate of drug resistance at treatment failure when combined with TDF in HAART regimens independently of the third drug used.

Better adherence with once-daily antiretroviral regimens: a meta-analysis

Once-daily regimens of antiretroviral therapy are simpler than other regimens, but whether such regimens are associated with better adherence to treatment is controversial. We performed a meta-analysis of 11 randomized, controlled trials (total number of subjects, 3029), which revealed that the adherence rate was better with once-daily regimens (+2.9%; 95% confidence interval, 1.0%-4.8%; P < .003) than with twice-daily regimens. This modest effect was more pronounced at the time of treatment initiation and for regimens for which all medications were taken once per day.

Long-term safety and efficacy results of once-daily emtricitabine-based highly active antiretroviral therapy regimens in human immunodeficiency virus-infected pediatric subjects

OBJECTIVES

The purpose of this work was to obtain long-term safety and efficacy data for antiretroviral regimens containing emtricitabine in HIV-infected pediatric subjects and confirm that a pediatric dose of 6 mg/kg once daily would provide steady-state emtricitabine concentrations comparable to those observed in adults given 200 mg of emtricitabine once daily.

PATIENTS AND METHODS

HIV-infected subjects between 3 months and 16 years of age were enrolled, including 71 antiretroviral-naïve subjects and 45 antiretroviral-experienced subjects. Naive subjects received emtricitabine plus stavudine plus lopinavir or ritonavir. Experienced subjects replaced the lamivudine in their existing regimens with emtricitabine. Tolerance, safety, disease progression, and virologic and immunologic responses were evaluated.

RESULTS

The Kaplan-Meier probability of persistent virologic response in the intent-to-treat population through week 164 at < or = 400 copies per mL and < or = 50 copies per mL was 74% and 62%, respectively. Three subjects (3%) discontinued the study for adverse events, 8 (7%) for virologic failure, and 1 died through a median follow-up of 164 weeks. The annualized incidence rate of grade 3 to 4 adverse events and grade 3 to 4 laboratory abnormalities was 6% and 3%, respectively. The annualized incidence rate of serious adverse events was 9%, with 1% attributed as related to emtricitabine. Genotypic analysis showed the emergence of the M184V mutation in 4 of the 15 subjects who experienced virologic failure through week 164. Pharmacokinetic evaluation demonstrated plasma drug exposures in these children comparable to adults receiving the approved dose of 200 mg once daily.

CONCLUSIONS

These results demonstrate the safety and efficacy of emtricitabine in pediatric patients. They also support that the safety and efficacy profile of emtricitabine in children is similar to that demonstrated in adults.

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.

A comparison of the phenotypic susceptibility profiles of emtricitabine and lamivudine

Emtricitabine (FTC) and lamivudine (3TC) are cytosine nucleoside analogues approved for use in HIV-1 infection. Both compounds select for the M184V/I mutation resulting in high-level resistance. This study compared the phenotypic resistance profiles of FTC and 3TC. Both compounds were tested against clinical samples submitted for routine resistance testing (PhenoSense HIV assay). We evaluated 306 viruses with nucleoside reverse transcriptase inhibitor mutations (NRTI-R) and 100 viruses without resistance mutations (WT). Seventy-two percent had > or = 1 thymidine analogue mutation (TAM), 21% had mixtures at M184, 14% had L74V and 7.5% had K65R. Results were expressed as fold change (FC) in 50% effective concentration compared with the NL4-3 reference. Concordance of FC was evaluated based on biological (99th percentile of the distribution of WT virus population) and clinical cutoffs (FC above which an optimal virological response declines). Against the WT viruses, FTC and 3TC had identical mean FC values relative to the NL4-3 reference of 0.9-fold +/- 0.2 and identical biological cutoffs of 1.4-fold against WT viruses. For NRTI-R isolates, there was a strong linear correlation between FTC and 3TC FC values (r2 = 0.94). Moreover, there was > 90% concordance in resistance calls based on either the biological (1.4-fold) or proposed clinical (3.5-fold) cutoffs among all NRTI-R isolates or isolates with M184V/I mixtures. In the absence of M184V/I, the majority of samples with resistance (> 3.5 FC) exhibited TAMs with a trend toward increased levels of cross-resistance with increasing numbers of TAMs. FTC and 3TC demonstrate nearly identical phenotypic resistance profiles and have the same biological cutoff in this panel of NRTI-R and WT clinical HIV-1 isolates.

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.

Evaluation of change in CD4+ cell counts in AIDS clinical trials

To evaluate the antiretroviral activity of antiretroviral agents and to compare the effects of two different antiretroviral agents, we propose a non-parametric mixed-effects model to investigate change of CD4+ counts. The proposed model and methods are applied to analyse the data from PACTG345 study. Population and individual patterns of change of CD4+ counts and a reference band are obtained. Our results indicate that treatment with high-dose ritonavir is significantly superior compared with low-dose ritonavir.

Pharmacokinetic evaluation of emtricitabine in combination with other nucleoside antivirals in healthy volunteers

Emtricitabine is a potent nucleoside reverse transcriptase inhibitor approved as a once-daily drug in combination with other antiretroviral agents for the treatment of HIV infection. Several phase I studies were conducted in healthy volunteers over the course of clinical development to evaluate whether pharmacokinetic drug-drug interactions exist between emtricitabine and other nucleoside antivirals that are extensively eliminated by renal excretion. Potential interactions with stavudine and famciclovir were evaluated in single-dose studies, whereas interactions with zidovudine and its major metabolite, zidovudine glucuronide, were evaluated in a multiple-dose study. Plasma pharmacokinetic profiles and, in some studies, urinary excretion data were evaluated when each drug was administered alone and in combination with emtricitabine. Safety and plasma pharmacokinetic profiles of each drug administered alone or with emtricitabine were consistent with historical data. Statistical analyses indicated that there were no significant interactions between emtricitabine and these 3 nucleoside antivirals.

No response to first-line tenofovir+lamivudine+efavirenz despite optimization according to baseline resistance testing: impact of resistant minority variants on efficacy of low genetic barrier drugs

BACKGROUND

Resistance testing has been implemented into clinical guidelines as it has shown some beneficial effect on subsequent therapy response.

CASE REPORT

Routine population-based genotypic resistance testing for a newly diagnosed HIV-1 patient revealed the presence of resistance mutations M41L, V179D and T215E within reverse transcriptase and no mutations within protease. Four weeks after initiation of the combination tenofovir+lamivudine+efavirenz, no response was observed despite good adherence to therapy and efavirenz drug levels in the therapeutic range. Retrospective single genome sequencing of the baseline sample revealed the presence of minority viral variants with additional mutations: a mutation conferring resistance to lamivudine (M184IV), a thymidine associated mutation (K219R) and mutations possibly associated with non-nucleoside reverse transcriptase resistance (F227S, M230IV).

CONCLUSIONS

This case illustrates that undetected drug-resistant minority variants can reduce the efficacy of a normally very potent first-line regimen tenofovir+lamivudine+efavirenz. The presence of drug-resistance mutations at diagnosis should be considered as a warning sign against the use of low genetic barrier drugs in first-line regimens, even when these drugs are considered to be active according to routine resistance testing.

Efavirenz/emtricitabine/tenofovir disoproxil fumarate fixed-dose combination: first-line therapy for all?

ATRIPLA (Bristol-Myers Squibb and Gilead Sciences) is a complete regimen in a single, fixed-dose combination tablet that contains: efavirenz 600 mg, emtricitabine 200 mg and tenofovir disoproxil fumarate 300 mg. Current treatment guidelines recommend this triple combination for initial therapy because of its excellent potency, tolerability and favorable safety profile. Individually, these agents have long half-lifes that allow for once-daily dosing and may provide a pharmacologic bridge for the occasional missed dose. Although several options for once-daily regimens are available, comparative clinical trials are still in progress. This article reviews relevant efficacy and safety data of efavirenz, emtricitabine and tenofovir disoproxil fumarate, compared with other once-daily agents or certain common alternate drugs presently used as initial therapy in treatment-naive patients.

Methodological standards in non-inferiority AIDS trials: moving from adherence to compliance

Background

The interpretation of the results of active-control trials regarding the efficacy and safety of a new drug is important for drug registration and following clinical use. It has been suggested that non-inferiority and equivalence studies are not reported with the same quantitative rigor as superiority studies.

Methods

Standard methodological criteria for non-inferiority and equivalence trials including design, analysis and interpretation issues were applied to 18 recently conducted large non-inferiority (15) and equivalence (3) randomized trials in the field of AIDS antiretroviral therapy. We used the continuity-corrected non-inferiority chi-square to test 95% confidence interval treatment difference against the predefined non-inferiority margin.

Results

The pre-specified non-inferiority margin ranged from 10% to 15%. Only 4 studies provided justification for their choice. 39% of the studies (7/18) reported only intent-to-treat (ITT) analysis for the primary endpoint. When on-treatment (OT) and ITT statistical analyses were provided, ITT was favoured over OT for results interpretation for all but one study, inappropriately in this statistical context. All but two of the studies concluded there was "similar" efficacy of the experimental group. However, 9/18 had inconclusive results for non-inferiority.

Conclusion

Conclusions about non-inferiority should be drawn on the basis of the confidence interval analysis of an appropriate primary endpoint, using the predefined criteria for non-inferiority, in both OT and ITT, in compliance with the non-inferiority and equivalence CONSORT statement. We suggest that the use of the non-inferiority chi-square test may provide additional useful information.

An Update and Review of Antiretroviral Therapy

The human immunodeficiency virus (HIV) was discovered in 1982, but treatment strategies were not introduced until 5 years later. Early regimens consisted of one or two drugs and often led to treatment failure. Since the advent in 1995 of highly active antiretroviral therapy (HAART), which consists of at least three agents, a dramatic improvement has been seen in the number of patients attaining undetectable viral loads, improved CD4 counts, and improved survival. However, early HAART often consisted of drugs with complex dosing schedules, strict food requirements, treatment-limiting adverse effects, and the need to take 16-20 pills/day. These treatment barriers often led to patient nonadherence, with subsequent treatment failure and development of resistant strains. The CD4 count and viral load are the most important surrogate markers used to determine if treatment is indicated. Current guidelines suggest starting treatment in patients who are symptomatic with an acquired immunodeficiency syndrome-defining illness regardless of CD4 count or viral load, as well as in asymptomatic patients with a CD4 count of 350 cells/mm(3) or below. In patients with CD4 counts above 350 cells/mm(3) and viral loads above 100,000 copies/ml, some clinicians prefer to defer treatment, whereas others will consider starting therapy; treatment is deferred in patients with CD4 counts above 350 cells/mm(3) and viral load s below 100,000 copies/ml. If therapy is started, the selection of appropriate agents is based on comorbidities (liver disease, depression, cardiovascular disease), pregnancy status, adherence potential (dosage regimen, pill burden, dosing frequency), food restrictions (dosing with regard to meals), adverse drug effects, and potential drug-drug interactions. Within the last 8 years, newer antiretroviral agents have focused on ways to improve adherence, such as convenient dosing (fewer pills), pharmacokinetic and formulation changes to reduce dosing frequency or pill burden, and coformulated dosage forms that contain two or three drugs in one convenient pill. Other improvements include increased potency of newer agents, agents sensitive to a highly resistant virus, improved adverse-effect profile (e.g., less gastrointestinal effects, improved lipid profiles), as well as protease inhibitor boosting with ritonavir, which takes advantage of the potent cytochrome P450 inhibitory action of ritonavir. This review focuses on the concepts of antiretroviral therapy, barriers to successful antiretroviral treatment, developments to limit treatment barriers, and new drug entities for the treatment of HIV.

Use of tenofovir disoproxil fumarate and emtricitabine combination in HIV-infected patients

With the continuing spread of HIV infection, particularly in developing countries, cost-effective treatment for its management is a high priority. Truvada (Gilead Sciences) is a single combination pill of the nucleotide reverse transcriptase inhibitors tenofovir disoproxil fumarate and emtricitabine, which is used once daily. It is anticipated to be a clinically potent combination that is free of short-term irritating toxicity. The drug has recently been licensed but there are currently little clinical efficacy data regarding its use. The limited published data have indicated that emtricitabine and lamivudine have equivalent potency, and randomised controlled trials have produced evidence of the efficacy of lamivudine combined with tenofovir disoproxil fumarate in a regimen containing either the non-nucleoside reverse transcriptase inhibitor efavirenz or a protease inhibitor lopinavir/ritonavir. In these trials, long-term durability data are available for < or = 96 weeks.

New antiretroviral drugs in clinical use

The advent of combination antiretroviral therapy for the treatment of human immunodeficiency virus (HIV) infection has dramatically changed the prognosis and quality of life of HIV-infected adults and children. To date, there are 21 antiretroviral agents available with only 11 agents being approved for the use in young children less than 6 years of age. The currently available antiretroviral agents belong to four different classes; nucleoside/nucleotide reverse transcriptase inhibitors (NRTI, NtRTI), non-nucleoside reverse transcriptase inhibitors (NNRTI), protease inhibitors (PI), and a new class of fusion inhibitors (FI). It is recommended that the treatment regimen should be a combination of at least 3 drugs from different drug classes as this has been shown to slow disease progression, improve survival, and result in better virologic and immunologic responses. Treatment with antiretroviral agents is frequently complicated by the issues of adherence, tolerability, long term toxicity and drug resistance. Many efforts have been made to develop new antiretroviral agents with greater potency, higher tolerability profiles and better convenience. Some new agents are also effective against drug-resistant strains of HIV. Since 2001, there were 7 new antiretroviral agents and 2 fixed-dose multidrug formulations being approved for the treatment of HIV infection, most are approved only for use in adults. In this article, we will review new antiretroviral agents including emtricitabine, tenofovir disoproxil fumarate, atazanavir, fosamprenavir, tipranavir and enfuvirtide. Pediatric information on these drugs will be provided when available.

Emtricitabine

Emtricitabine (Emtriva) is an orally administered nucleoside reverse transcriptase inhibitor (NRTI) that is indicated in combination with other antiretroviral agents in the treatment of HIV infection in adults. As a component of antiretroviral therapy (ART), emtricitabine effectively reduces and/or maintains suppression of viral load in ART-naive adults or ART-experienced adults switching from stable combination regimens, and is generally well tolerated. Emtricitabine is a component of preferred initial HIV combination therapy regimens; it can be used in place of lamivudine as part of the dual NRTI backbone in non-nucleoside reverse transcriptase inhibitor (NNRTI)- and protease inhibitor (PI)-based regimens. Moreover, preliminary data from a randomised, open-label study suggest that emtricitabine plus tenofovir DF, a preferred dual-NRTI combination, is better tolerated than co-formulated lamivudine/zidovudine, another preferred dual-NRTI combination, resulting in a higher persistent virological response rate, as analysed using the US FDA time to loss of virological response (TLOVR) algorithm. With the convenience of once-daily (single pill) administration, no dietary restrictions and a favourable drug interaction and tolerability profile, emtricitabine should facilitate patient adherence to treatment, which, in turn, is central to the success of antiretroviral therapy. Similarly, emtricitabine is attractive as an option for ART-experienced stable adults requiring regimen simplification.