A randomized comparative trial of tenofovir DF or abacavir as replacement for a thymidine analogue in persons with lipoatrophy

[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.

A meta-analysis of six placebo-controlled trials of thiazolidinedione therapy for HIV lipoatrophy

OBJECTIVE

To determine the impact of thiazolidinediones (TZD) on changes in limb fat mass in HIV-infected individuals, particularly in those not receiving a thymidine analogue.

METHODS

Individual patient data from placebo-controlled, randomized trials of rosiglitazone (n = 5) or pioglitazone (n = 1) were combined. Generalized estimating equation (GEE) models were used to estimate the treatment effect on changes in limb fat mass.

RESULTS

In the combined dataset of 427 patients, the baseline median age was 45 years, 86% were male, 80% were Caucasian, 63% were receiving stavudine (d4T) or zidovudine (AZT), 66% were on protease inhibitors, and median body mass index was 23 kg/m(2). In a univariate GEE model, TZD was associated with an increase in limb fat mass (coeff = 0.14 kg vs placebo, P = .04). In a multivariable GEE model, patients receiving pioglitazone had significantly higher limb fat mass gains (coeff = 0.35 kg, P < or = .01) compared to patients receiving placebo, while patients on rosiglitazone did not (coeff = 0.05 kg, P = .48). Interactions between thymidine analogue use and rosiglitazone and pioglitazone were not significant.

CONCLUSIONS

In this meta-analysis, pioglitazone therapy was more effective than placebo to increase limb fat mass whereas rosiglitazone was not significantly better than placebo. The effectiveness of these drugs did not vary according to whether the patients were receiving thymidine analogues.

Longitudinal study of body composition of 101 HIV men with lipodystrophy: dual-energy X-ray criteria for lipodystrophy evolution

The aim of this study was to define evolution profiles of body composition among human immunodeficiency virus (HIV)-infected men with lipodystrophy. The design is a retrospective analysis using observational data collected longitudinally. We included 101 HIV-infected men with lipodystrophy managed in routine practice and who had 2 dual energy X-ray absorptiometry scans within a minimum interval of 18 mo. Lipodystrophy was defined as a fat mass ratio (FMR, defined as the ratio of the percentage of the trunk fat mass over the percentage of the lower limbs fat mass) equal or superior to 1.5. Patients were classified in "improved" group (IG: increase of lower limbs fat mass >/= 10%) or "nonimproved" group (NIG). Body composition, immunovirological and epidemiological data were collected and compared between the 2 groups. In the whole population, over a 4-yr period, a significant increase was observed for total fat mass, trunk fat mass, and lower limbs fat mass, whereas total lean mass was stable. Total body mineral density decreased. Fifty-nine patients (IG), less exposed to zidovudine than the NIG, had an increase of lower limbs fat mass higher than 10%. But only 13 (22%) regained a normal distribution of fat mass (FMR < 1.5), showing that lipodystrophy was slowly reversible. Among the NIG, 5 patients (11.9%), less exposed to zidovudine and with a higher mean of viral load, reached an FMR below 1.5. It was mainly because of a loss of trunk fat mass, which could be the sign of a lipodystrophy worsening. Lipodystrophy improved for 58.4% of men. The improvement was very slow. Recovery was observed only in patients with an earlier intervention. No correlation was observed between lipodystrophy and total body bone mineral density. The loss of trunk fat mass without gain of lower limbs fat mass may indicate a worsening of HIV disease.

Antiretroviral therapy with heart

Antiretroviral therapy (ART) has resulted in a substantial improvement in the morbidity and mortality associated with human immunodeficiency virus (HIV) infection. As this population ages, cardiovascular disease is becoming an increasingly important health burden. It is clear that many factors are involved in the development of this problem, with traditional risk factors (smoking, dyslipidemia, diabetes, family history, hypertension) the main contributors. ART and HIV infection itself can modify the risk of cardiovascular disease. Not only does this increased risk seem to be mediated through effects on traditional cardiovascular risk factors, namely dyslipidemia and insulin resistance, but there is also some evidence that HIV and ART may be associated with accelerated atherosclerosis and endothelial dysfunction. Current data are conflicting and further investigation into this area is needed. Drugs from both nucleoside reverse transcriptase inhibitor and protease inhibitor classes have been demonstrated to increase cardiovascular risk; however these effects are variable not only between classes but also between drugs in the same class. As newer therapies become available (in existing and new drug classes), the cardiovascular impact of these will need careful evaluation. Currently published guidelines suggest regular monitoring of cardiovascular risks (both before and after commencing ART) and pre-emptive treatment. Existing risk assessment tools have not been fully validated in an HIV setting and need to be used with caution. Lifestyle modification, in the first instance, and pharmacological intervention to reduce traditional risk factors are important management strategies. Initiating, or switching to, ART with a lower potential for metabolic derangement should also be considered.

The effects of intermittent, CD4-guided antiretroviral therapy on body composition and metabolic parameters

OBJECTIVE

To assess the effects of decreased antiretroviral therapy exposure on body fat and metabolic parameters.

DESIGN

Substudy of the Strategies for Management of Anti-Retroviral Therapy study, in which participants were randomized to intermittent CD4-guided [Drug Conservation (DC) group] or to continuous [Viral Suppression (VS) group] antiretroviral therapy.

METHODS

Participants at 33 sites were coenrolled in the Strategies for Management of Anti-Retroviral Therapy Body Composition substudy. Regional fat was assessed annually by whole-body dual-energy X-ray absorptiometry and abdominal computed tomography. Fasting metabolic parameters were assessed at months 4, 8, and annually. Treatment groups were compared for changes in fat and metabolic markers using longitudinal mixed models.

RESULTS

Two hundred and seventy-five patients were randomized to the DC (n = 142) or VS (n = 133) group and followed for a median of 2.0 years. By month 12, limb fat (DC-VS difference 9.8%, 95% confidence interval 3.5-16.1; P = 0.003) and subcutaneous abdominal fat (DC-VS difference 14.3 cm, 95% confidence interval -0.1 to 28.7; P = 0.05) increased in the DC group. There was no treatment difference in visceral abdominal fat (DC-VS difference -2.1%, 95% confidence interval -13.5 to 9.4; P = 0.72). Lipids significantly decreased in the DC group by month 4 and treatment differences persisted throughout follow-up (P < or = 0.001). By 12 months, hemoglobin A1C increased in the DC (+0.3%) and remained stable in the VS group (P = 0.003); the treatment difference remained significant throughout follow-up (P = 0.02).

CONCLUSION

After 12 months, intermittent antiretroviral therapy increased subcutaneous fat, had no effect on visceral abdominal fat, decreased plasma lipids, and increased hemoglobin A1C compared with continuous antiretroviral therapy.

Switching the nucleoside reverse transcriptase inhibitor backbone to tenofovir disoproxil fumarate + emtricitabine promptly improves triglycerides and low-density lipoprotein cholesterol in dyslipidaemic patients

OBJECTIVES

To assess the impact of switching to tenofovir disoproxil fumarate + emtricitabine on lipid parameters.

METHODS

HIV-infected patients with plasma viral load <400 copies/mL, fasted triglycerides from 2.3 to 11.4 mmol/L and/or fasted low-density lipoprotein (LDL)-cholesterol >4.1 mmol/L were randomized to switch the nucleoside reverse transcriptase inhibitor (NRTI) backbone to fixed-dose combination tenofovir disoproxil fumarate + emtricitabine or to maintain the baseline antiretroviral regimen (the control group). The study has been registered with ClinicalTrials.gov under the identifier NCT00323492.

RESULTS

Ninety-one patients were included in the intent-to-treat (ITT) analysis with triglycerides 2.4 mmol/L and LDL-cholesterol 4.0 mmol/L (median values). At week 12, the median changes from baseline of triglycerides were -0.5 mmol/L (-25%; n = 46) and -0.1 mmol/L (-6%; n = 45) in the tenofovir disoproxil fumarate + emtricitabine and control groups, respectively, indicating a difference of -0.4 mmol/L (P = 0.034) [95% confidence interval (CI): -0.9 to -0.0]. Similarly for LDL-cholesterol, changes of -0.4 mmol/L (-9%) and -0.1 mmol/L (-1%) were observed in the tenofovir disoproxil fumarate + emtricitabine and control groups, respectively, indicating a difference of -0.4 mmol/L (P = 0.031) [95% CI: -0.7 to -0.0]. The proportion of patients with LDL-cholesterol >4.1 mmol/L decreased from 48% at baseline to 26% at week 12 in the tenofovir disoproxil fumarate + emtricitabine group versus no change in the control group. No virological failure was observed during the study.

CONCLUSIONS

Switching to tenofovir disoproxil fumarate + emtricitabine in dyslipidaemic HIV-infected patients improves triglycerides and LDL-cholesterol.

Prevalence and impact of body physical changes in HIV patients treated with highly active antiretroviral therapy: results from a study on patient and physician perceptions

Patients infected with HIV treated with highly active antiretroviral therapy (HAART) frequently develop body physical changes (BPC) that have an important psychosocial burden. The purpose of this study was to determine the prevalence of BPC observed by HIV-infected patients and their attending physicians and to assess the impact BPC had on daily life. In this epidemiologic multicenter study, patients with HIV infection and their treating physicians filled out parallel questionnaires about their perceptions of specific BPC and their impact on daily activities. A total of 965 patient-physician questionnaires were collected across 98 health centers. Patient's mean age was 43.7 +/- 8.5 years and 72.6% were men. Adjusted prevalence of perceived BPC by patients and physicians was 55.1% (95% confidence interval [CI]: 52.0-58.1) and 55.2% (95% CI: 52.1-58.2), respectively (p = 1.000). Overall patient-physician agreement concerning perception of BPC was 83% (p < 0.0005). The most common BPC was lipoatrophy, described by 46.8% (95% CI: 43.7-49.8) of patients and 49.4% (95% CI: 46.3-52.5) of physicians (p = 0.033) followed by lipohypertrophy. No gender differences were observed in the global prevalence of BPC (p = 0.649). However, significantly more women reported lipoatrophy of the lower limbs (p = 0.009) and buttocks (p = 0.007), as well as lipohypertrophy (p = 0.007), than men; 58.2% (95% CI: 54.0-62.4) patients noted that BPC negatively affected their daily activities. This study reflects the high prevalence of patient and physician-perceived BPC in the HIV population, and the adverse impact on daily life. Physicians should be aware of the psychosocial consequences of BPC in HIV patients in order to improve patient well-being.

Adipocyte dysfunction in response to antiretroviral therapy: clinical, tissue and in-vitro studies

PURPOSE OF REVIEW

Lipodystrophy, a major complication of antiretroviral therapy, is an adipose tissue disease involving severe alterations of fat tissue distribution and metabolic functions. Protease inhibitors and nucleoside reverse transcriptase inhibitors (NRTIs) are implicated to different extents. We review recent findings on the toxicity of HIV antiretroviral drugs at the fat cell and tissue levels and point out the underlying pathophysiological mechanisms.

RECENT FINDINGS

Peripheral fat loss and central accumulation are distinct phenomena. Lipoatrophy is the dominant feature after prolonged treatment. Protease inhibitors and NRTIs promote fat tissue disease by separate mechanisms that converge and worsen adipocyte dysfunctions. The pathogenesis involves the mitochondrial toxicity of NRTIs and the adverse effects of protease inhibitors and NRTIs on adipocyte differentiation status, insulin sensitivity, survival and adipokine secretion. Oxidative stress and local inflammation induced by these drugs may participate in the setup of lipodystrophy. Partial and slow reversion can be obtained by switch strategies or drug therapy.

SUMMARY

Patients using antiviral therapy develop severe fat tissue damage. The toxicity of protease inhibitors and NRTIs remains an important issue for patients and clinicians. Since fat tissue regeneration is difficult, it is important to understand the mechanisms by which these drugs alter fat tissue depots.

LIPODYSTROPHY SYNDROME IN HIV-INFECTED CHILDREN ON HAART

Lipodystrophy syndrome (LD) is common in HIV-infected children, particularly those taking didanosine, stavudine or zidovudine. Lipo-atrophy in particular causes major stigmatisation and interferes with adherence. In addition, LD may have significant long-term health consequences, particularly cardiovascular. Since the stigmatising fat distribution changes of LD are largely permanent, the focus of management remains on early detection and arresting progression. Practical guidelines for surveillance and avoidance of LD in routine clinical practice are presented. The diagnosis of LD is described and therapeutic options are reviewed. The most important therapeutic intervention is to switch the most likely offending antiretroviral to a non-LD-inducing agent as soon as LD is recognised. Typically, when lipoatrophy or lipohypertrophy is diagnosed the thymidine nucleoside reverse transcriptase inhibitor (NRTI) is switched to a non-thymidine agent such as abacavir (or tenofovir in adults). Where dyslipidaemia is predominant, a dietician review is helpful, and the clinician may consider switching to a protease inhibitor-sparing regimen or to atazanavir.

Statin therapy and changes in hip circumference among HIV-infected participants in the ALLRT Cohort

BACKGROUND

We aimed to determine whether statin exposure in antiretroviral-treated individuals is associated with increases in hip circumference compared with HIV treatment without concomitant statin use.

METHODS

This was a prospective multicentre cohort study involving individuals who had received antiretroviral therapy for at least 40 weeks and who were enrolled in the AIDS Clinical Trials Group Longitudinal Linked Randomized Trials cohort. There were 2,223 participants in the statin-unexposed group and 371 in the statin-exposed group. The main outcome measure was change in hip circumference at week 32.

RESULTS

The 32-week change in hip circumference in the statin-exposed group was 0.60 cm greater (95% confidence interval 0.11-1.10; P=0.02) than in the statin-unexposed group after adjustment for age, gender, race, baseline body mass index and thymidine analogue exposure.

CONCLUSIONS

Our findings support the hypothesis that statins might be beneficial in lipoatrophy. Given the limited treatment options for this important problem, further studies are needed to confirm this effect and to determine its clinical significance.

Abacavir-lamivudine versus tenofovir-emtricitabine for initial HIV-1 therapy

BACKGROUND

The use of fixed-dose combination nucleoside reverse-transcriptase inhibitors (NRTIs) with a nonnucleoside reverse-transcriptase inhibitor or a ritonavir-boosted protease inhibitor is recommended as initial therapy in patients with human immunodeficiency virus type 1 (HIV-1) infection, but which NRTI combination has greater efficacy and safety is not known.

METHODS

In a randomized, blinded equivalence study involving 1858 eligible patients, we compared four once-daily antiretroviral regimens as initial therapy for HIV-1 infection: abacavir-lamivudine or tenofovir disoproxil fumarate (DF)-emtricitabine plus efavirenz or ritonavir-boosted atazanavir. The primary efficacy end point was the time from randomization to virologic failure (defined as a confirmed HIV-1 RNA level > or = 1000 copies per milliliter at or after 16 weeks and before 24 weeks, or > or = 200 copies per milliliter at or after 24 weeks).

RESULTS

A scheduled interim review by an independent data and safety monitoring board showed significant differences in virologic efficacy, according to the NRTI combination, among patients with screening HIV-1 RNA levels of 100,000 copies per milliliter or more. At a median follow-up of 60 weeks, among the 797 patients with screening HIV-1 RNA levels of 100,000 copies per milliliter or more, the time to virologic failure was significantly shorter in the abacavir-lamivudine group than in the tenofovir DF-emtricitabine group (hazard ratio, 2.33; 95% confidence interval, 1.46 to 3.72; P<0.001), with 57 virologic failures (14%) in the abacavir-lamivudine group versus 26 (7%) in the tenofovir DF-emtricitabine group. The time to the first adverse event was also shorter in the abacavir-lamivudine group (P<0.001). There was no significant difference between the study groups in the change from the baseline CD4 cell count at week 48.

CONCLUSIONS

In patients with screening HIV-1 RNA levels of 100,000 copies per milliliter or more, the times to virologic failure and the first adverse event were both significantly shorter in patients randomly assigned to abacavir-lamivudine than in those assigned to tenofovir DF-emtricitabine. (ClinicalTrials.gov number, NCT00118898.)

Nucleoside and nucleotide HIV reverse transcriptase inhibitors: 25 years after zidovudine

Twenty-five years ago, nucleoside analog 3'-azidothymidine (AZT) was shown to efficiently block the replication of HIV in cell culture. Subsequent studies demonstrated that AZT acts via the selective inhibition of HIV reverse transcriptase (RT) by its triphosphate metabolite. These discoveries have established the first class of antiretroviral agents: nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs). Over the years that followed, NRTIs evolved into the main component of antiretroviral drug combinations that are now used for the treatment of all populations of HIV infected patients. A total of thirteen NRTI drug products are now available for clinical application: eight individual NRTIs, four fixed-dose combinations of two or three NRTIs, and one complete fixed-dose regimen containing two NRTIs and one non-nucleoside RT inhibitor. Multiple NRTIs or their prodrugs are in various stages of clinical development and new potent NRTIs are still being identified through drug discovery efforts. This article will review basic principles of the in vitro and in vivo pharmacology of NRTIs, discuss their clinical use including limitations associated with long-term NRTI therapy, and describe newly identified NRTIs with promising pharmacological profiles highlighting those in the development pipeline. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, volume 85, issue 1, 2010.

Successful implementation of a national HLA-B*5701 genetic testing service in Canada

Abacavir is a nucleoside reverse transcriptase inhibitor (NRTI) that is used in combination antiretroviral therapy in HIV-infected patients. It is currently recommended as a preferred or an alternative NRTI in antiretroviral-naïve patients. The major toxicity of abacavir is a hypersensitivity reaction (HSR), which occurs in approximately 5% of treated patients. There is a strong association between the human leukocyte antigen (HLA)-B*5701 allele and abacavir HSR, which has allowed for rapid acceptance of genetic screening for HLA-B*5701 in clinical use. Canadian clinicians working in hospital centers with HLA typing capacity opted to launch a pilot project in 2006 to offer the screening test as standard of care to HIV-infected patients. Currently, more than 11,000 HLA-B*5701 tests have been performed, among which 6.3% are positive. Continued efforts have been made to ensure that testing is available to all HIV-infected patients to widen the patients' therapeutic options. HLA-B*5701 screening shows clinical use and preliminary data suggest cost-effectiveness.

Impact of metabolic complications on antiretroviral treatment adherence: clinical and public health implications

Antiretroviral therapy (ART) is an effective strategy for preventing disease progression of HIV infection, particularly when patients adhere closely to the treatment regimen. However, ART medications can cause side effects, including metabolic complications that can impact patients' adherence levels. Selected chronic complications associated with ART include lipodystrophy, hyperlipidemia, insulin resistance and diabetes, peripheral neuropathy, and bone disorders such as osteopenia/osteoporosis. In this article, we review the effects of these metabolic complications on ART adherence and approaches to prevent or reverse them.

Efficacy and safety of atazanavir-ritonavir plus abacavir-lamivudine or tenofovir-emtricitabine in patients with hyperlipidaemia switched from a stable protease inhibitor-based regimen including one thymidine analogue

Randomized, open-label, prospective clinical trial assessing efficacy and safety on hyperlipidemia of a switching from a regimen including one protease inhibitor and one thymidine analogue to atazanavir/ritonavir plus abacavir/lamivudine or tenofovir/emtricitabine. Adult HIV-infected patients on their first antiretroviral therapy (of at least 48-week duration), including one protease inhibitor and zidovudine or stavudine, with stable immunovirologic features, and having diagnosis of persisting hyperlipidemia, were randomized to replace current treatment with atazanavir/ritonavir plus abacavir/lamivudine (arm A) or tenofovir/emtricitabine (arm B), and were followed for 48 weeks. Eighty-nine patients were enrolled: 42 patients were randomized to arm A, and 47 to arm B. At the end of the 48-week follow-up, incidence of virologic failure was comparable in both arms, and associated with a poor drug compliance. Increase in CD4 lymphocyte count was significantly higher in arm A after a 24-week study period (62.5 versus 39.2 x 10(6) cells/L; p < 0.05), while immunologic responses were comparable at the end of 48-week follow-up (91.5 versus 83.6; p > 0.05). A statistically significant reduction (-15.4%) in mean triglyceridaemia versus respective baseline values was reported in both groups (p < 0.05), without statistically significant difference between arm A and B. Similar results were reported for total cholesterol and low-density lipoprotein (LDL) cholesterol levels. Safety and tolerability profiles were comparable in both groups. Switching from a protease inhibitor- and thymidine analogue-based antiretroviral regimen to atazanavir/ritonavir plus abacavir/lamivudine or tenofovir/emtricitabine proved effective in the management of hyperlipidemia, without significant differences in lipid-lowering effect, virologic efficacy, and safety profile between these regimens.

A randomized comparative trial of continued zidovudine/lamivudine or replacement with tenofovir disoproxil fumarate/emtricitabine in efavirenz-treated HIV-1-infected individuals

BACKGROUND

Long-term antiretroviral therapy dramatically reduces HIV-related morbidity and mortality but is also associated with metabolic and morphological changes and requires high levels of adherence.

METHODS

A randomized, 48-week, open-label, comparative study of continuation of twice-daily zidovudine/lamivudine or replacement with once-daily tenofovir disoproxil fumarate/emtricitabine in individuals on successful efavirenz-based antiretroviral therapy. Limb fat mass was assessed by dual x-ray absorptiometry in a subset of participants through week 48.

RESULTS

Two hundred thirty-four individuals were randomized and treated (117 each to continue or switch) with 206 subjects completing 48 weeks of study. Five percent subjects in the continue group and 3% subjects in the switch group discontinued due to adverse events. By intent-to-treat, missing = failure analysis, no differences in virological efficacy were observed at any time point (week 48 <50 copies/mL continue 85%, switch 88%). At week 24, switching was associated with significant increases in hemoglobin (mean difference 0.37 g/dL, 95% confidence interval: 0.15 to 0.58 g/dL, P < 0.001) and significant declines in total cholesterol and triglycerides. In the dual x-ray absorptiometry substudy (n = 100), fat was preserved or increased in the switch group but declined in the continue group (mean difference 448 g, 95% confidence interval: 57 to 839 g, P = 0.025). Individuals with longer exposure to zidovudine and lower baseline limb fat experienced less limb fat increase after switching. No differences in renal adverse events were observed between groups.

CONCLUSIONS

Switching from zidovudine/lamivudine to tenofovir disoproxil fumarate/emtricitabine in persons on efavirenz therapy maintains virological control, establishes a once-daily regimen, results in improvements in hemoglobin and key lipid parameters, and preserves and restores limb fat relative to continuation of zidovudine/lamivudine.

Abacavir and risk of myocardial infarction in HIV-infected patients on highly active antiretroviral therapy: a population-based nationwide cohort study

OBJECTIVE

The aim of the study was to examine whether exposure to abacavir increases the risk for myocardial infarction (MI).

DESIGN, SETTING AND SUBJECTS

This was a prospective nationwide cohort study which included all Danish HIV-infected patients on highly active antiretroviral therapy (HAART) from 1995 to 2005 (N = 2952). Data on hospitalization for MI and comorbidity were obtained from Danish medical databases. Hospitalization rates for MI after HAART initiation were calculated for patients who used abacavir and those who did not. We used Cox's regression to compute incidence rate ratios (IRR) as a measure of relative risk for MI, while controlling for potential confounders (as separate variables and via propensity score) including comorbidity.

MAIN OUTCOME

Relative risk of hospitalization with MI in abacavir users compared with abacavir nonusers.

RESULTS

Hospitalization rates for MI were 2.4/1000 person-years (PYR) [95% confidence interval (CI) 1.7-3.4] for abacavir nonusers and 5.7/1000 PYR (95% CI 4.1-7.9) for abacavir users. The risk of MI increased after initiation of abacavir [unadjusted IRR = 2.22 (95% CI 1.31-3.76); IRR adjusted for confounders = 2.00 (95% CI 1.10-3.64); IRR adjusted for propensity score = 2.00 (95% CI 1.07-3.76)]. This effect was also observed among patients initiating abacavir within 2 years after the start of HAART and among patients who started abacavir as part of a triple nucleoside reverse transcriptase inhibitor (NRTI) regimen.

CONCLUSIONS

We confirmed the association between abacavir use and increased risk of MI. Further studies are needed to control for potential confounding not measured in research to date.

Effectiveness of antiretroviral regimens containing abacavir with tenofovir in treatment-experienced patients: predictors of virological response and drug resistance evolution in a multi-cohort study

BACKGROUND

In treatment-naïve patients, a combination antiretroviral therapy (cART) containing tenofovir (TDF) and abacavir (ABC) with lamivudine leads to unacceptably high virological failure rates with frequent selection of reverse transcriptase mutations M184V and K65R. We explored the efficacy of at least 16 weeks of ABC + TDF-containing cART regimens in 307 antiretroviral-experienced HIV-1-infected individuals included in observational databases.

METHODS

Virological failure was defined as an HIV RNA > 400 copies/ml after at least 16 weeks of treatment. Patients had received a median of three prior cART regimens. Of these, 76% concomitantly received a potent or high genetic barrier regimen (with at least one protease inhibitor [PI]) or non-nucleoside reverse transcriptase inhibitor or thymidine analogue) while a third non-thymidine nucleoside analogue was used in the remaining patients.

RESULTS

The 1-year estimated probability of virological failure was 34% in 165 patients with HIV RNA > 400 copies/ ml at ABC + TDF regimen initiation. Independent predictors of virological failure were the absence of a potent or high genetic barrier cART, the higher number of cART regimens experienced, and the use of a new drug class. In the subset of 136 patients for whom there were genotypic resistance test results prior to ABC + TDF initiation, the virological failure (1-year estimated probability 46%) was independently predicted by the higher baseline viral load, the concomitant use of boosted PI, and the presence of reverse transcriptase mutation M41L. In 142 patients starting ABC + TDF therapy with HIV RNA pound < or =400 copies/ml, virological failure (1-year estimated probability 17%) was associated only with the transmission category. In a small subset of subjects for whom there were an available paired baseline and follow-up genotype (n = 28), the prevalence of most nucleoside analogue reverse transcriptase inhibitor resistance mutations decreased, suggesting a possible low adherence to treatment. No selection of K65R was detected.

CONCLUSION

The virological response to ABC + TDF-containing regimens in this moderately-to-heavily treatment experienced cohort was good. Higher viral load and the presence of M41L at baseline were associated with worse virological responses, while the concomitant prescription of drugs enhancing the genetic barrier of the regimen conveyed a reduced risk of virological failure. The Appendix provides the names of other members of the MASTER cohort.

A simplification trial switching from nucleoside reverse transcriptase inhibitors to once-daily fixed-dose abacavir/lamivudine or tenofovir/emtricitabine in HIV-1-infected patients with virological suppression

BACKGROUND

Data comparing abacavir/lamivudine versus tenofovir/emtricitabine in antiretroviral-naive patients are controversial. We compared 48-week efficacy and safety of these combinations as substitutes of nucleosides in patients with virological suppression.

METHODS

We randomly assigned 333 HIV-1-infected patients on lamivudine-containing triple regimens with <200 copies per milliliter for at least 6 months to switch their nucleosides to either abacavir/lamivudine (n = 167) or tenofovir/emtricitabine (n = 166). The primary outcome was treatment failure ["switching = failure" intention to treat (ITT) analysis, noninferiority margin 12.5%]. Secondary outcomes were time to treatment failure, virological failure, adverse events, and changes in CD4 count, fasting plasma lipids, lipodystrophy, body fat, bone mineral density, and renal function.

RESULTS

Treatment failure occurred in 32 patients (19%) on abacavir/lamivudine and 22 patients (13%) on tenofovir/emtricitabine [difference 5.9%; (95% confidence interval -2.1% to 14.0%), P = 0.06]. Four patients in the abacavir/lamivudine group versus none in the tenofovir/emtricitabine group developed virological failure [difference 2.4; (95% confidence interval 0.05 to 6.0), P = 0.04]. Twenty-three patients (14%) assigned to abacavir/lamivudine and 10 (6%) to tenofovir/lamivudine experienced grade 3 or 4 adverse effects (P = 0.03). CD4 counts and plasma lipids showed higher increments in the abacavir/lamivudine group than in the tenofovir/emtricitabine group.

CONCLUSIONS

In HIV-1-infected patients with virological suppression, abacavir/lamivudine did not meet the noninferiority outcome for treatment efficacy compared with tenofovir/emtricitabine.

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).

Considering the individual - principles of treatment choice

Although several antiretroviral agents are available, realistic options for initial therapy remain limited, as many are not licensed for treatment-naive patients, as reflected in national and international guidelines. A variety of factors influence treatment choice. From the physicians’ perspective, it is important to consider age, sex, co-morbid conditions, concomitant drugs and potential for adherence. Meanwhile, patients are concerned about the impact of side-effects on their day-to-day life and long-term future, drug efficacy, future options and time available in clinics. Patients’ concerns may be alleviated by detailed discussion throughout treatment, including the importance of adherence, the pros and cons of different treatments and potential side-effects. Positive outcomes in terms of not just viral load and CD4 counts but also improved duration and quality of life should be emphasized. Treatment must be tailored to each patient to maximize benefits and minimize risks.

Zidovudine/lamivudine for HIV-1 infection contributes to limb fat loss

Background

Lipoatrophy is known to be associated with stavudine as part of the treatment for HIV infection, but it is less clear if this serious side effect is also related to other nucleoside reverse transcriptase inhibitors like zidovudine. We aimed to determine whether zidovudine-sparing first-line antiretroviral therapy would lead to less lipoatrophy and other metabolic changes than zidovudine-containing therapy.

Methodology/Principal Findings

Fifty antiretroviral therapy-naïve HIV-1 infected men with an indication to start antiretroviral therapy were included in a randomized single blinded clinical trial. Randomisation was between zidovudine-containing therapy (zidovudine/lamivudine+lopinavir/ritonavir) and zidovudine-sparing therapy (nevirapine+lopinavir/ritonavir). Main outcome measures were body composition assessed by computed tomography and dual-energy X-ray absorptiometry scan and lipid profile before and after 3, 12, 24 months of antiretroviral therapy. In the zidovudine/lamivudine+lopinavir/ritonavir group, from 3 months onward limb fat decreased progressively by 684±293 grams (estimated mean±standard error of the mean)(p = 0.02) up to 24 months whereas abdominal fat increased, but exclusively in the visceral compartment (+21.9±8.1 cm², p = 0.008)). In contrast, in the nevirapine+lopinavir/ritonavir group, a generalized increase in fat mass was observed. After 24 months no significant differences in high density lipoprotein and total/high density lipoprotein cholesterol ratio were found between both treatment groups, but total and low density lipoprotein cholesterol levels were higher in the nevirapine+lopinavir/ritonavir group (6.1±0.2 versus 5.3±0.2 and 3.6±0.1 versus 2.8±0.1 mmol/l respectively, p<0.05). Virologic response and safety were comparable in both groups.

Conclusions/Significance

Zidovudine/lamivudine+lopinavir/ritonavir, but not nevirapine+lopinavir/ritonavir in antiretroviral therapy-naïve patients, is associated with lipoatrophy and greater relative intraabdominal lipohypertrophy, suggesting that zidovudine/lamivudine contributes to both these features of lipodystrophy. These findings support to no longer consider zidovudine/lamivudine as one of the preferred possible components of first-line antiretroviral therapy where alternative treatments are available.

Trial Registration

ClinicalTrials.gov NCT 00122226

A new era of antiretroviral drug toxicity

The spectrum of drugs used in HIV-infected patients has dramatically changed since triple antiretroviral combinations were introduced, albeit at the expense of some severe adverse events, in 1996. Abandonment of stavudine in countries that can afford it, new drugs from new classes with a wide therapeutic window and the impressive scale-up of drug access in resource-limited settings are several of the key new events. Drug safety is likely to be the most important factor to distinguish one antiretroviral regimen from another. We review life-threatening adverse events, adverse events of new investigational or recently marketed drugs, adverse events with a genetic component and tissue-specific adverse events of fat, heart, bone, kidney and liver.

A randomized trial of two-drug versus three-drug tenofovir-containing maintenance regimens in virologically controlled HIV-1 patients

OBJECTIVES

To assess simplified maintenance regimens containing dual antiretroviral drugs in patients with controlled human immunodeficiency virus type 1 infection.

METHODS

A non-inferiority, randomized, multicentre, open-label trial was performed in 24 AIDS clinical centres in France randomizing 143 patients [treated for >or=6 months, plasma viral load (pVL) <50 copies/mL, no prior history of treatment failure] to receive a two-drug regimen [tenofovir disoproxil fumarate (tenofovir DF) and efavirenz] or to maintain a three-drug treatment (tenofovir DF, lamivudine and efavirenz). The main outcome measure was the success rate (percentage of patients with pVL <50 copies/mL without treatment modifications) at week 48.

RESULTS

Success rates for the intention-to-treat analysis were 97.2% (70/72) versus 81.7% (58/71) in the three-drug versus two-drug maintenance regimen groups, respectively [difference, 15.5%; upper limit of one-sided 95% confidence interval (CI), 23.7%], and 100% (70/70) versus 90% (54/60) for the per protocol analysis, respectively (difference, 10%; upper limit of one-sided 95% CI, 16.4%), with a non-inferiority margin set at 14%. Three patients from the two-drug group experienced virological failure with selection of efavirenz-associated mutations. Overall, CD4 counts were significantly increased from baseline (median, +24 cells/mm(3); P = 0.007). Four patients discontinued study treatment due to adverse events in the two-drug group and none in the three-drug group. No significant changes in creatinine clearance or phosphataemia were reported. Overall, levels of triglycerides, total and high-density lipoprotein cholesterol were improved; low-density lipoprotein cholesterol was improved only in the three-drug group.

CONCLUSIONS

The non-inferiority of the two-drug versus the three-drug regimen was not demonstrated. Lipid parameters improved after switching from twice-daily highly active antiretroviral therapy (HAART) to once-daily tenofovir-based HAART.

Four-year safety with polyacrylamide hydrogel to correct antiretroviral-related facial lipoatrophy

Infiltrations with synthetic substances are effective strategies for repairing facial lipoatrophy. However, few data are available on long-term safety. We describe the safety of polyacrylamide hydrogel in 145 patients who received facial infiltrations with Aquamid from September 2002 to April 2004. Epidemiological, clinical (mainly complications), and psychological data (patient satisfaction) were collected. We also recorded all patients who presented with a local infection at any time after receiving an infiltration. Sixty-two percent of patients presented with severe facial lipoatrophy before infiltration. The cumulative volume of Aquamid injected was 5.5 ml (4-18) per patient. During a mean (SD) of 50.2 (4.3) months after infiltration, only one patient presented with a local infection. Small palpable, nonvisible nodules or indurations were the most frequent complications (19.3% and 6.2%, respectively). If we include the remaining patients from our center (n = 294) who also received Aquamid (although less than 4 years ago), a further three patients presented with a local infection (incidence of 0.9%). Most patients (88.9%) were "satisfied" or "very satisfied" with the results; patients with mild to moderate baseline facial lipoatrophy were more satisfied than those with severe lipoatrophy ("very satisfied": 92.7% versus 86.5%, respectively). Only 17.4% reported mild impairment of lipoatrophy and only 9.2% required new infiltrations; however, 76% would have preferred more infiltrations. The high patient satisfaction and the low number of severe complications after at least 4 years of facial infiltrations with Aquamid reflect the long-term safety of this product for the repair of facial lipoatrophy. However, prolonged follow-up of these patients is recommended to detect unexpected long-term adverse reactions.

Mitochondrial function, morphology and metabolic parameters improve after switching from stavudine to a tenofovir-containing regimen

OBJECTIVES

HIV-associated lipoatrophy has been associated with mitochondrial dysfunction induced by nucleoside reverse transcriptase inhibitor therapy. We hypothesize that lipid profiles and markers of mitochondrial function will improve in HIV-lipoatrophic patients switched to the nucleotide analogue tenofovir.

METHODS

Ten patients receiving stavudine, lamivudine and lopinavir/ritonavir (Kaletra(R)) for over 6 years were switched from stavudine to tenofovir for 48 weeks. Subcutaneous fat tissue biopsies, fasting metabolic tests, HIV RNA, CD4 cell count and whole body dual energy X-ray absorptiometry (DEXA) scans were obtained at study entry and week 48. Mitochondrial DNA (mtDNA) copies/cell and mitochondrial morphology were assessed in adipose tissue biopsies, mtDNA 8-oxo-deoxyguanine in peripheral blood mononuclear cells, and glutathione (GSH) and F2-isoprostane in plasma.

RESULTS

There was no change in limb fat mass by DEXA; however, trunk fat mass increased by 18.9% (P = 0.01). Fasting total cholesterol decreased by 33 mg/dL (P = 0.005) and serum glucose decreased by 4 mg/dL (P = 0.039). mtDNA copies/cell increased from 386 to 1537 (P < 0.001). Transmission electron microscopy showed that mitochondrial cristae were lacking or poorly defined at study entry, whereas mitochondrial inner structures were more well defined and outer membranes were intact at 48 weeks. Oxidative damage decreased in 8/10 patients, GSH increased and F2-isoprostane decreased.

CONCLUSIONS

The results from this study demonstrate that systemic and peripheral fat mitochondria improve in patients switched to tenofovir following long-term exposure to stavudine, while continuing protease inhibitor therapy.

Endothelial activation markers are linked to HIV status and are independent of antiretroviral therapy and lipoatrophy

OBJECTIVES

To assess the association of inflammatory and endothelial activation biomarkers with the presence of lipoatrophy in HIV-infected subjects and to examine the role of HIV, antiretroviral therapy (ART), and metabolic parameters in endothelial activation and inflammation.

DESIGN

Prospective, cross-sectional study including 4 groups: HIV+ on ART with HIV-1 RNA<1000 copies/mL with and without clinical lipoatrophy, HIV+ ART naive, and healthy controls.

METHODS

We measured plasma levels of inflammatory cytokines (tumor necrosis factor-alpha, soluble tumor necrosis factor receptors I and II, interleukin-6, C-reactive protein, and myeloperoxidase) and endothelial activation markers (soluble intercellular and vascular cell adhesion molecules and von Willebrand factor).

RESULTS

We enrolled 182 subjects. Limb fat and lipoatrophy status were not correlated with endothelial markers. Endothelial markers were higher in HIV+ ART naive when compared with healthy controls and with HIV+ on ART but were similar between HIV+ on ART and healthy controls. Neither endothelial nor inflammatory markers were correlated with HIV duration, CD4 count, lipids, glucose, or specific ART. Strong correlations were found between some inflammatory cytokines and endothelial markers.

CONCLUSIONS

There is enhanced endothelial activation in ART naive, whereas HIV+ on ART has similar values to healthy controls. Lipoatrophy did not seem to affect endothelial activation. Results highlight a potential association between heightened inflammation and endothelial activation.

Peripheral and visceral fat changes following a treatment switch to a non-thymidine analogue or a nucleoside-sparing regimen in HIV-infected subjects with peripheral lipoatrophy: results of ACTG A5110

BACKGROUND

Switching a thymidine analogue to a non-thymidine analogue or changing to a nucleoside-sparing regimen has been shown to partially reverse peripheral lipoatrophy. The current study evaluated both approaches.

METHODS

Subjects at 15 AIDS Clinical Trial Group sites receiving thymidine analogue stavudine- or zidovudine-containing regimens with plasma HIV RNA < or =500 copies/mL and lipoatrophy were prospectively randomized to: (i) switch the thymidine analogue to abacavir; (ii) discontinue all antiretrovirals and switch to lopinavir/ritonavir plus nevirapine (LPV/r+NVP); or (iii) delay switching for 24 weeks (ClinicalTrials.gov identifier: NCT00028314). Single-slice computer tomography of mid-thigh and abdominal fat and metabolic and virological/immunological parameters were measured at baseline and weeks 24 and 48.

RESULTS

Among the 101 patients enrolled, there were significant subcutaneous thigh fat and subcutaneous abdominal tissue (SAT) increases over time and decreases in visceral adipose tissue to total adipose tissue (VAT:TAT) ratios for both interventions, and a decrease in VAT for abacavir. CD4 increased in the LPV/r+NVP arm. LPV/r+NVP had a significantly shorter time to grade 3 or higher toxicity (P = 0.007), but discontinuation rates were similar. Glucose levels did not change, but insulin decreased in the LPV/r+NVP arm. Lipids tended to increase in the LPV/r+NVP arm.

CONCLUSIONS

Switching stavudine or zidovudine to a non-thymidine analogue or changing to a nucleoside reverse transcriptase inhibitor-sparing regimen is associated with qualitatively similar improvements in thigh fat, SAT and VAT:TAT ratio at 48 weeks. Abacavir also resulted in VAT reductions and LPV/r+NVP resulted in CD4 count increases.

Improvements in cheek volume in lipoatrophic individuals switching away from thymidine nucleoside reverse transcriptase inhibitors

BACKGROUND

Thymidine nucleoside reverse transcriptase inhibitors (NRTIs) are associated with subcutaneous fat loss. Facial changes cannot be assessed by dual-energy X-ray absorptiometry (DEXA) scans. There are limited objective data on the reversibility of facial lipoatrophy.

METHODS

We performed a facial volume substudy of a randomized thymidine NRTI replacement study carried out in HIV-infected subjects with moderate to severe lipoatrophy. Facial volume changes were assessed using validated 3D laser imaging. Changes in body composition were measured using DEXA scans. The association between changes in facial volume and body composition parameters at 48 weeks was measured using Spearman's rank correlation.

RESULTS

Forty-seven individuals (46 male), 11 receiving zidovudine and 36 receiving stavudine, switched to either tenofovir disoproxil fumarate (DF) (n=23) or abacavir (ABC) (n=24). Thirty-nine of these 47 patients (84.8%) reported facial lipoatrophy at baseline. The median volume increase in both cheeks from baseline was 1857.3 mm(3). These volume changes and increases in limb fat at 48 weeks were similar in the two groups and correlated significantly (Spearman's r=0.41, P=0.004).

CONCLUSIONS

Facial volume in lipoatrophic individuals was found to increase after thymidine NRTI replacement. We demonstrated a significant correlation between improvements in facial and limb fat parameters. Switching from thymidine NRTIs in patients with facial lipoatrophy could potentially reduce the need for cosmetic interventions.

Impact of lipoatrophy on quality of life in HIV patients receiving anti-retroviral therapy

Metabolic and morphological side-effects occur in HIV-infected individuals receiving anti-retroviral treatment (ART). Peripheral fat loss that occurs particularly in the face, limbs and/or buttocks is referred to as lipoatrophy and has been found to be highly stigmatizing and to adversely impact the health-related quality of life (HRQL). Consumer Health Sciences Survey data collected between November 2003 and January 2006 were utilized to evaluate the impact of lipoatrophy on the HRQL in HIV-infected individuals receiving ART. This was evaluated using analysis of variance with item scores and mental component summary (MCS) and physical component summary (PCS) scores from the Medical Outcomes Trust questionnaire, SF-8 as dependent variables and lipoatrophy as the independent variable controlling for baseline age, sex and ethnicity. Clinical meaningfulness (mean difference divided by population standard deviation, delta/sigma) of differences between the groups with and without lipoatrophy was also evaluated. A cohort of 1124 subjects with at least six months of ART was selected based on the availability of data on whether or not lipoatrophy was present. Subjects were primarily male (80%), between the ages of 30 and 60 years (90%), Hispanic (37%) and about 25% each of African American and White. Overall, prevalence of lipoatrophy in this cohort of HIV patients was 18.9%. Statistically significant (p<0.001) differences in quality of life (as measured by SF-8 individual item scores and MCS and PCS scores) were observed between the two groups. The differences between the groups in item and summary scores were clinically meaningful in the small to near medium range (0.28-0.43). HIV-infected patients already experience a considerable deficiency in HRQL compared to general population; this study demonstrates that lipoatrophy further enhances that negative impact on HRQL.

Treatment options for HIV-associated central fat accumulation

Central fat accumulation is increasingly recognized as a problem for patients with HIV infection. The term "lipodystrophy" has been used to describe collectively a constellation of body habitus changes and metabolic abnormalities commonly observed in HIV-infected patients, particularly since the advent of highly active antiretroviral therapy. Visceral fat accumulation can place patients at increased risk of coronary artery disease.Furthermore, body shape changes are a source of distress to patients that may compromise treatment adherence.Reduction of abdominal obesity can therefore be considered part of therapy in HIV-positive patients with visceral adipose tissue (VAT) accumulation. Currently, there are no drugs approved by the Food and Drug Administration for the treatment of HIV-associated central fat accumulation. Lifestyle modifications such as diet and exercise and switching antiretroviral therapies appear to be of limited value in reducing VAT. Metformin has shown some benefit in reducing VAT but at the expense of accelerating peripheral fat loss, and the thiazolidinediones have no effect on VAT. Similarly, testosterone does not appear to reduce VAT in these patients,and there are no data on anabolic steroids. Two large, randomized controlled trials have demonstrated the efficacy of recombinant human growth hormone (rhGH) in reducing visceral adipose tissue. There are also promising data regarding treatment with growth hormone releasing hormone (GHRH).

The effects of Thiazolidinediones on metabolic complications and Lipodystrophy in HIV-infected patients

Highly active antiretroviral therapy (HAART)-associated metabolic complications include lipoatrophy (loss of subcutaneous adipose tissue (SAT)) and insulin resistance. Thiazolidinediones are insulin-sensitizing antidiabetic agents which-as an untoward side effect in obese diabetic patients-increase SAT. Furthermore, troglitazone has improved lipoatrophy and glycemic control in non-HIV patients with various forms of lipodystrophy. These data have led to 14 clinical trials to examine whether thiazolidinediones could be useful in the treatment of HAART-associated metabolic complications. The results of these studies indicate very modest, if any, effect on lipoatrophic SAT, probably due to ongoing HAART negating the beneficial effect. The benefit might be more prominent in patients not taking thymidine analoges. Despite the poor effect on lipoatrophy, thiazolidin-ediones improved insulin sensitivity. However, especially rosiglitazone induced harmful effects on blood lipids. Current data do not provide evidence for the use of thiazolidinediones in the treatment of HAART-associated lipoatrophy, but treatment of lipoatrophy-associated diabetes may be warranted. The role of thiazolidinediones for novel indications, such as hepatosteatosis, should be studied in these patients.

Treatment of altered body composition in HIV-associated lipodystrophy: comparison of rosiglitazone, pravastatin, and recombinant human growth hormone

PURPOSE

Treatment options for HIV-associated lipodystrophy syndrome (HALS) remain limited. The objective of this randomized open-label study was to compare three emerging therapies, rosiglitazone, pravastatin, and growth hormone alone and together, in men and women with HALS.

METHOD

Sixty-four subjects received daily rosiglitazone (4 mg, n = 14), pravastatin (40 mg, n = 11), or rosiglitazone plus pravastatin (n = 13) for 48 weeks or recombinant human growth hormone (rhGH; Serostim 2 mg, 12 weeks, n = 13) alone or combined with rosiglitazone (n = 13). Primary endpoint was body composition change by dual X-ray absorptiometry (DXA) and computed tomography (CT).

RESULTS

Rosiglitazone resulted in slow accrual of limb fat detected by DXA (+444 +/- 186 g; p < .05) but not CT. Pravastatin had no consistent significant effects on body composition, although it reduced total and LDL cholesterol. Negative interactions were observed between pravastatin and rosiglitazone. rhGH reduced abdominal fat by CT (-31 +/- 15 cm2, 26%; p < .05) and DXA (-1597 +/- 383 g, 27%; p < .05) and increased trunk and limb lean mass (+10% and +12%, respectively). However, effects largely disappeared within 12 weeks post treatment. rhGH alone impaired insulin sensitivity but not when combined with rosiglitazone.

CONCLUSION

Prolonged rosiglitazone treatment slowly improves lipoatrophy. rhGH rapidly and selectively reduces visceral fat, although effects are short-lived; co-administered rosiglitazone abrogates rhGH-related insulin resistance.

Chronic administration of tenofovir to rhesus macaques from infancy through adulthood and pregnancy: summary of pharmacokinetics and biological and virological effects

The reverse transcriptase (RT) inhibitor tenofovir (TFV) is highly effective in the simian immunodeficiency virus (SIV) macaque model of human immunodeficiency virus infection. The current report describes extended safety and efficacy data on 32 animals that received prolonged (>or=1- to 13-year) daily subcutaneous TFV regimens. The likelihood of renal toxicity (proximal renal tubular dysfunction [PRTD]) correlated with plasma drug concentrations, which depended on the dosage regimen and age-related changes in drug clearance. Below a threshold area under the concentration-time curve for TFV in plasma of approximately 10 microg x h/ml, an exposure severalfold higher than that observed in humans treated orally with 300 mg TFV disoproxil fumarate (TDF), prolonged TFV administration was not associated with PRTD based on urinalysis, serum chemistry analyses, bone mineral density, and clinical observations. At low-dose maintenance regimens, plasma TFV concentrations and intracellular TFV diphosphate concentrations were similar to or slightly higher than those observed in TDF-treated humans. No new toxicities were identified. The available evidence does not suggest teratogenic effects of prolonged low-dose TFV treatment; by the age of 10 years, one macaque, on TFV treatment since birth, had produced three offspring that were healthy by all criteria up to the age of 5 years. Despite the presence of viral variants with a lysine-to-arginine substitution at codon 65 (K65R) of RT in all 28 SIV-infected animals, 6 animals suppressed viremia to undetectable levels for as long as 12 years of TFV monotherapy. In conclusion, these findings illustrate the safety and sustained benefits of prolonged TFV-containing regimens throughout development from infancy to adulthood, including pregnancy.

Tenofovir: what have over 1 million years of patient experience taught us?

Several groundbreaking trials and over 1 million years of patient experience have established tenofovir as an important component of HIV treatment. Tenofovir has demonstrated potent antiviral efficacy, with a low risk of developing resistance when used as part of an effective combination regimen. It is generally well tolerated, with a low risk of lipoatrophy and a favourable effect on lipid profile compared with older nucleoside analogue agents such as stavudine or zidovudine. Clinical data suggest that switching from thymidine analogues to a tenofovir-containing regimen can benefit patients with lipid abnormalities or lipoatrophy. This article reviews the development of tenofovir, including pivotal studies that have influenced HIV clinical practice.

Effect of reducing the dose of stavudine on body composition, bone density, and markers of mitochondrial toxicity in HIV-infected subjects: a randomized, controlled study

BACKGROUND

Stavudine is widely used in developing countries. Lipoatrophy and mitochondrial toxicity have been linked to stavudine use, but it is unclear whether switching to a lower dose can reduce these toxicities while maintaining human immunodeficiency virus (HIV) suppression.

METHODS

HIV-infected subjects receiving standard-dose stavudine with undetectable HIV type 1 RNA for > or =6 months were randomized (ratio, 3:2) to receive one-half of the stavudine dose (switch arm) or to maintain the dose (continuation arm) while continuing to receive all other prescribed antiretrovirals. The following measurements were obtained at baseline and week 48: fasting lactate, pyruvate, and lipid levels; results of whole-body dual-energy x-ray absorptiometry; and mitochondrial DNA (mtDNA) measurements in fat and peripheral blood mononuclear cells. Change from baseline to week 48 was compared within and between groups.

RESULTS

Twenty-four patients (79% of whom were men and 79% of whom were African American; median age, 45 years) were enrolled in the study, 15 were enrolled in the switch arm, and 9 were enrolled in the continuation arm. The median duration of stavudine treatment was 55 months (range, 21-126 months). The median CD4 cell count was 558 cells/mm(3) (range, 207-1698 cells/mm(3)). At baseline, the study arms had similar demographic characteristics and laboratory indices, except for body mass index, total lean body mass, and triglyceride levels (all of which were higher in the switch arm). Three patients (2 in the switch arm) discontinued the study because of study-unrelated reasons. CD4 cell counts remained unchanged. At 48 weeks, 6 patients (4 [27%] in the switch arm and 2 [22%] in the continuation arm) had detectable HIV RNA levels (median, 972 copies/mL; range, 60-49,400 copies/mL). All patients with detectable HIV RNA levels reported significant lapses in treatment adherence; none exhibited mutations in HIV genotype. After the treatment switch, significant changes from study entry to week 48 were noted only for lactate level (median change, -0.27 mmol/L; range, -1.2 to 0.25 mmol/L; P = .02) and fat mtDNA (median change, 40 copies/cell; range, -49 to 261 copies/cell; P = .02). In the continuation arm, a significant loss of bone mineral density was seen at week 48 (median change, -1.7%; range, -6.3% to 0.8%; P = .02). The only significant between-group difference was the change in bone mineral density from baseline (P = .003).

CONCLUSIONS

Reducing stavudine dose by one-half increased fat mtDNA and decreased lactate levels, suggesting improvement in mitochondrial indices while preserving HIV suppression in subjects who maintained adherence. A significant loss of bone mineral density was seen in patients receiving standard-dose stavudine but not in those receiving low-dose stavudine. These results suggest that switching to low-dose stavudine may improve mitochondrial indices while maintaining virological suppression.

Initial therapy with nucleoside reverse transcriptase inhibitor-containing regimens is more effective than with regimens that spare them with no difference in short-term fat distribution: Hippocampe-ANRS 121 Trial

OBJECTIVES

The aim of this study was to evaluate the impact on body fat of nucleoside reverse transcriptase inhibitor (NRTI)-sparing regimens compared with NRTI-containing therapy in HIV-1-infected antiretroviral (ARV)-naive patients.

METHODS

A randomized, multicentre, open-label trial in ARV-naive patients. Subjects were randomized (2:1:1) to receive: (i) an NRTI-sparing regimen consisting of a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus a boosted protease inhibitor (PI/r); or (ii) an NRTI-containing regimen of (a) a PI/r plus two NRTIs or (b) an NNRTI plus two NRTIs. The primary endpoint was the change in subcutaneous limb fat measured by dual-energy X-ray absorptiometry at week (W) 96. Secondary endpoints included the proportion of patients with treatment failure, plasma HIV-RNA (pVL) <50 copies/mL and safety.

RESULTS

One hundred and seventeen patients were enrolled between November 2003 and May 2004: 26% female; 42% from sub-Saharan Africa; median plasma HIV-RNA (pVL) 5.1 log(10) copies/mL; median CD4 count 207 cells/mm(3). A planned interim analysis demonstrated significantly lower treatment and virological responses with the NRTI-sparing strategy, resulting in premature study termination on 19 July 2005. The proportion of patients who remained on their assigned treatment strategy and had pVL <50 copies/mL on the NRTI-sparing regimen was 60.0%, compared with 82.5% on the NRTI-containing regimen at W24 (P = 0.009) and 66.7% and 82.5%, respectively, at W48 (P = 0.059). Treatment failure was associated with the NRTI-sparing strategy in patients with suboptimal adherence and with being from sub-Saharan Africa. No differences in fat distribution were noted.

CONCLUSIONS

An initial NRTI-sparing regimen is less successful and virologically less potent than standard NRTI-containing regimen and should not therefore be used as the first line of treatment.