Switch studies: a review

Abacavir/Lamivudine plus Rilpivirine Is an Effective and Safe Strategy for HIV-1 Suppressed Patients: 48 Week Results of the SIMRIKI Retrospective Study

Objectives

Based on data from clinical practice, we evaluated the effectiveness and safety of switching to abacavir/lamivudine plus rilpivirine (ABC/3TC+RPV) treatment in virologically suppressed HIV-1-infected patients.

Methods

We performed a multicenter, non-controlled, retrospective study of HIV-1-infected patients who switched treatment to ABC/3TC+RPV. Patients had an HIV-RNA <50 copies/mL for at least 24 weeks prior to changing treatments. The primary objective was HIV-1 RNA <50 copies/mL at week 48. Effectiveness was analyzed by intention-to-treat (ITT), missing = failure and on-treatment (OT) analyses. The secondary objectives analyzed were adverse effects changes in renal, hepatic or lipid profiles, changes in CD4+ cell count and treatment discontinuations.

Results

Of the 205 patients included, 75.6% were men and the median age was 49. At baseline, before switching to ABC/3TC+RPV, median time since HIV diagnosis was 13.1 years, median time with undetectable HIV-1 RNA was 6.2 years and median time of previous antiretroviral regimen was 3.1 years (48.3% patients were taking efavirenz and ABC/3TC was the most frequent backbone coformulation in 69.7% of patients). The main reasons for switching were drug toxicity/poor tolerability (60.5%) and simplification (20%). At week 48, the primary objective was achieved by 187 out of 205 (91.2%) patients by ITT analysis, and 187 out of 192 (97.4%) patients by OT analysis. The CD4+ lymphocyte count and CD4+ percentage increased significantly from baseline to week 48 by a median of 48 cells/μL (−50 to 189) and 1.2% (−1.3% to 4.1%), respectively, P<0.001. Thirty-eight adverse events (AE) were detected in 32 patients. Of these, 25 had no clear association with treatment. Three patients interrupted therapy due to AE. We observed a decrease in all lipid parameters, P<0.001, and a slight improvement in the glomerular filtration rate, P<0.01. Therapy was considered to have failed in 18 patients owing to virological failure (5 [2.4%]), toxicity/poor tolerability (4 [2%]), clinical decision (3 [1.5%]), loss to follow-up (3 [1.5%]), death (1 [0.5%]), and no clinical data (2 [1%]).

Conclusions

The results of this study confirms that ABC/3TC+RPV is an effective, safe, and cost-effective option for the treatment of patients with virologically stable HIV-1 infection.

Substitution with Lopinavir/Ritonavir Improves Patient-Reported Outcomes Including Quality of Life in Patients Who Were Intolerant to Their Antiretroviral Therapy

PURPOSE

Adverse effects are important determinants of quality of life (QOL) during highly active antiretroviral therapy (HAART). The PLATO study investigated the association between changes in patient-reported outcomes including QOL and substitution with lopinavir/ritonavir in patients experiencing side effects (SEs).

METHOD

HIV-1-infected participants (N = 849) with undetectable viral load experiencing Grade-2 SEs of the protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI) component of their HAART regimen were randomized to immediate (baseline) or deferred (week 4) substitution with lopinavir/ritonavir soft-gel capsules 400/100 mg bid. The primary endpoint was change in the total score from the AIDS Clinical Trials Group (ACTG) Symptoms Distress Module (ASDM), supplemented with two items for nephrolithiasis. Secondary endpoints included Medical Outcomes Study (MOS)-HIV scores and Center for Epidemiologic Studies-Depression (CES-D) scores.

RESULTS

Immediate substitution resulted in improved ASDM total score at week 4 compared with deferred substitution (p <.001) and significant improvements in all MOS-HIV domains, while significant improvement was observed in CES-D scores at week 8. Primary SEs resolved at week 8 in 65% of participants in the immediate substitution group. Suppression of HIV-1 was maintained. Treatment was well-tolerated and associated with elevations in cholesterol and triglycerides.

CONCLUSION

Substitution with LPV/r improved patient-reported outcomes including QOL in patients experiencing Grade-2 SEs, while maintaining viral suppression.

Reuse of nevirapine in exposed HIV-infected children after protease inhibitor-based viral suppression: a randomized controlled trial

CONTEXT

Protease inhibitor (PI)-based therapy is recommended for infants infected with human immunodeficiency virus (HIV) who were exposed to nevirapine for prevention of mother-to-child HIV transmission. However, there are limitations of continuing PI-based therapy indefinitely and reuse of nevirapine has many advantages.

OBJECTIVE

To test whether nevirapine-exposed infants who initially achieve viral suppression with PI-based therapy can maintain viral suppression when switched to nevirapine-based therapy.

DESIGN, SETTING, AND PATIENTS

Randomized trial conducted between April 2005 and May 2009 at a hospital in Johannesburg, South Africa, among 195 children who achieved viral suppression less than 400 copies/mL for 3 or more months from a cohort of 323 nevirapine-exposed children who initiated PI-based therapy before 24 months of age.

INTERVENTIONS

Control group children continued to receive ritonavir-boosted lopinavir, stavudine, and lamivudine (n = 99). Switch group children substituted nevirapine for ritonavir-boosted lopinavir (n = 96).

MAIN OUTCOME MEASURES

Children were followed up for 52 weeks after randomization. Plasma HIV-1 RNA of greater than 50 copies/mL was the primary end point. Confirmed viremia greater than 1000 copies/mL was used as a criterion to consider regimen changes for children in either group (safety end point).

RESULTS

Plasma viremia greater than 50 copies/mL occurred less frequently in the switch group (Kaplan-Meier probability, 0.438; 95% CI, 0.334-0.537) than in the control group (0.576; 95% CI, 0.470-0.668) (P = .02). Confirmed viremia greater than 1000 copies/mL occurred more frequently in the switch group (0.201; 95% CI, 0.125-0.289) than in the control group (0.022; 95% CI, 0.004-0.069) (P < .001). CD4 cell response was better in the switch group (median CD4 percentage at 52 weeks, 34.7) vs the control group (CD4 percentage, 31.3) (P = .004). Older age (relative hazard [RH], 1.71; 95% CI, 1.08-2.72) was associated with viremia greater than 50 copies/mL in the control group. Inadequate adherence (RH, 4.14; 95% CI, 1.18-14.57) and drug resistance (RH, 4.04; 95% CI, 1.40-11.65) before treatment were associated with confirmed viremia greater than 1000 copies/mL in the switch group.

CONCLUSION

Among HIV-infected children previously exposed to nevirapine, switching to nevirapine-based therapy after achieving viral suppression with a ritonavir-boosted lopinavir regimen resulted in lower rates of viremia greater than 50 copies/mL than maintaining the primary ritonavir-boosted lopinavir regimen.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00117728.

The roles of HIV-1 proteins and antiretroviral drug therapy in HIV-1-associated endothelial dysfunction

Since the emergence of highly active antiretroviral therapy (HAART), human immunodeficiency virus-1 (HIV-1)-infected patients have demonstrated dramatic decreases in viral burden and opportunistic infections, and an overall increase in life expectancy. Despite these positive HAART-associated outcomes, it has become increasingly clear that HIV-1 patients have an enhanced risk of developing cardiovascular disease over time. Clinical studies are instrumental in our understanding of vascular dysfunction in the context of HIV-1 infection. However, most clinical studies often do not distinguish whether HIV-1 proteins, HAART, or a combination of these 2 factors cause cardiovascular complications. This review seeks to address the roles of both HIV-1 proteins and antiretroviral drugs in the development of endothelial dysfunction because endothelial dysfunction is the hallmark initial step of many cardiovascular diseases. We analyze recent in vitro and in vivo studies examining endothelial toxicity in response to HIV-1 proteins or in response to the various classes of antiretroviral drugs. Furthermore, we discuss the multiple mechanisms by which HIV-1 proteins and HAART injure the vascular endothelium in HIV-1 patients. By understanding the molecular mechanisms of HIV-1 protein- and antiretroviral-induced cardiovascular disease, we may ultimately improve the quality of life of HIV-1 patients through better drug design and the discovery of new pharmacological targets.

Successful simplification of protease inhibitor-based HAART with triple nucleoside regimens in children vertically infected with HIV

OBJECTIVE

To assess the virological, immunological and metabolic effects of switching from an efficacious first-line protease inhibitor (PI)-based HAART to a simplified triple nucleoside reverse transcriptase inhibitor (NRTI) regimen in children vertically infected with HIV.

DESIGN

Prospective, open-label, before-after study of 20 vertically infected children with at least 12 consecutive months of undetectable viral load under a PI-based HAART and no previous history of NRTI treatment.

METHODS

At study entry, HAART was shifted to a triple-NRTI combination.

RESULTS

The children were aged 2 to 18 years (median, 7.9) and were followed for 96 weeks. All were receiving a PI-based regimen for an average duration of 4 years before enrollment. At study entry, 12 patients (60%) switched to abacavir, 5 (25%) to lamivudine; 2 (10%) to zidovudine and 2 to didanosine (10%). All but one patient maintained plasma HIV RNA < 50 copies/ml during the entire follow-up. No immunological failure was observed at week 96. A trend of normalization (P < 0.001) of T cell receptor Vbeta families of the CD8 cell subset was detected in 19/20 (95%), with an increased HIV-specific CD8 T cell response (P < 0.01) in 17/20 (85%). Dyslipidaemia significantly improved during the follow up (P < 0.001). No new cases of lipodystrophy were detected.

CONCLUSIONS

Switching to triple-NRTI regimens in selected HIV-infected children with an extremely low likelihood of harbouring nucleoside-associated mutations maintains viral suppression and immunological function, improving metabolic abnormalities and the effort to take medication for up to 96 weeks.

Strategies for management and treatment of dyslipidemia in HIV/AIDS

With the improved survival of HIV-infected patients, there are increased concerns about the long-term effects of treatment, including protease inhibitor (PI)-related dyslipidemia. Some 50-70% of patients receiving combination antiretroviral therapy (ART) involving PIs develop lipid abnormalities consisting of elevated levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides that are well-known risk factors for cardiovascular disease. Treatment of HIV dyslipidemia should include lifestyle modifications such as a low-fat diet, increased exercise, reduced alcohol consumption and smoking cessation. In many patients, however, these changes alone will not correct lipid levels. In some patients, changing the PI component of ART to another PI or non-PI and/or lipid-lowering drugs has proven successful. Each approach is associated with advantages and limitations and the need to maintain viral suppression must be balanced with the need to treat abnormal lipid levels.

Evaluation of nevirapine-switch strategies for HIV treatment

Despite the benefits of protease inhibitor (PI)-based HIV treatment, issues of tolerability, dosing frequency, pill count and long-term metabolic complications necessitate evaluation of alternate treatment strategies. The weight of evidence demonstrates that a switch from a PI-based regimen to one containing nevirapine can be accomplished safely while maintaining virological suppression. There is no immunological cost. There is probably an overall benefit in terms of the metabolic milieu.

Synthesis and biological evaluation of phosphonated carbocyclic 2'-oxa-3'-aza-nucleosides

The synthesis of carbocyclic 2'-oxa-3'-aza-nucleosides has been described, based on the 1,3-dipolar cycloaddition of a new phosphonated nitrone with vinyl acetate followed by coupling with silylated nucleobases. The obtained compounds have been evaluated for their ability to inhibit the reverse transcriptase of avian myeloblastosis retrovirus: no significant activity has been observed.

Simplification Therapy with Once-Daily Didanosine, Tenofovir and Efavirenz in HIV-1-Infected Adults with Viral Suppression Receiving a More Complex Antiretroviral Regimen: Final Results of the EFADITE Trial

Background

High pill burden and side effects often impact on the long-term success of highly active anti-retroviral therapy (HAART), which has led clinicians to search for more convenient regimens.

Patients and methods

A prospective, multicentre, open, comparative study in which HIV-1-infected patients on HAART and with plasma HIV-1 RNA <50 copies/ml for longer than 6 months were switched to tenofovir, didanosine and efavirenz (QD arm) or remained on the same treatment regimen (control arm). Patients with grade 4 toxicities or plasma HIV-1 RNA values repeatedly >1000 copies/ml discontinued the study.

Results

A total of 390 patients were included in the trial (309 in the QD arm and 81 in the control arm). The main baseline characteristics were well balanced between groups. In the QD arm, 41% of patients received high (standard) didanosine doses and 59% received reduced doses. At 12 months, plasma HIV-1 RNA <400 copies/ml was attained in 66% of QD patients and 73% of controls in the intent-to-treat (ITT) analysis ( P=NS). However, the number of individuals with HIV-1 RNA <400 copies/ml in the QD arm was 56% versus 71% when comparing the use of high versus low didanosine doses ( P=0.007). Treatment discontinuation occurred in 87 QD cases (28%) and 17 controls (21%). Twenty QD individuals (6.5%) and 2 controls (2.5%) discontinued because of virological failure ( P=NS). The median CD4+ cell count change at 12 months was -26 and +27 cells/μl in QD patients and controls, respectively ( P=0.001). In individuals who attained HIV-1 RNA <400 copies/ml, CD4+ cell changes were -25 and +15 cells/μl in QD patients and controls, respectively ( P=0.001). Moreover, CD4+ cell declines in the QD arm were significantly greater in patients taking high versus low didanosine doses (-59 versus -15 cells/μl; P=0.04). The lipid profile improved significantly in the QD arm, particularly in patients who were on protease inhibitors prior to simplification.

Conclusions

Simplification to didanosine–tenofovir–efavirenz provides a virological suppression rate at 12 months similar to that seen in patients who do not change therapy, as long as low didanosine doses are administered. Decreases in CD4+ cell levels in patients in the QD arm (especially decreases seen with high didanosine doses) and dyslipidaemias along with less convenient pill burden and schedules in controls were the main long-term concerns for each option.

Nelfinavir in HIV-HCV coinfected patients: a 24-month follow-up in a cohort of 82 patients

This retrospective and longitudinal study evaluated the long-term hepatic tolerance of a nelfinavir (NFV)-antiretroviral combined regimen in 82 patients of the HCV-HIV Cohort of CISIH-Sud of Marseilles. Follow-up data (liver enzyme levels, CD4 cell count, HIV viral load, and metabolic parameters) of patients treated with NFV on inclusion or during the follow-up of the cohort were analyzed under treatment over 24 months. Comparisons were performed with X2 or Kruskal-Wallis tests. At baseline (n = 82), the median exposure to NFV was 4.1 months; 58 patients received NFV combined with NRTI and 24 with NNRTI. The median CD4 cell count was 337/mm3 [interquartile range (IR): 216-480) and 39.7% had an undetectable HIV RNA level. Qualitative HCV PCR was positive in 91% of the patients and 19/51 patients with liver biopsy were F3-F4. Median alanine and aspartate aminotransferase (ALAT, ASAT), gamma-glutamyltransferase (GT), and alkaline phosphatase (ALP) were 46 UI/liter (IR: 36-76), 55 UI/liter (IR: 32-97), 97 UI/liter (IR: 50-194), and 88 UI/liter (IR: 72-104), respectively, with 76% of the patients with ALAT/ASAT grade <2. Median follow-up was 23 months (IR: 13.8-37). No significant difference was observed in the distribution of ALAT, ASAT, GT, and ALP as well as of ALAT/ASAT grades over the 24-month study period. Patients treated with NFV + NNRTI had significantly higher GT and ALP levels at baseline with no significant increase during follow-up. Cholesterol, triglyceride, and glycemia distributions remained stable over time. In conclusion, this study showed a good hepatic and metabolic tolerance of a long-term NFV-combined regimen in HIV-HCV coinfected patients.

A randomized controlled trial investigating the efficacy and safety of switching from a protease inhibitor to nevirapine in patients with undetectable viral load

OBJECTIVE

To assess the antiviral efficacy and safety of switching from a protease inhibitor (PI) to nevirapine in patients with long-term HIV-1 RNA suppression on PI-containing regimens, and to assess its influence in the adherence to treatment.

METHODS

In an open-label multicentre study, 160 HIV-infected patients with undetectable viral load for at least 6 months on a PI-containing regimen were randomized to either continue with their PI regimen (n=79) or replace PI with nevirapine (n=81). Clinical assessment included plasma HIV-1 RNA, blood chemistry, haematology, lymphocyte counts and adverse events reports. Adherence to treatment and lipodystrophy syndrome were assessed by patient self-reporting.

RESULTS

Treatment efficacy was equivalent in the two arms, for patients with viral loads either above or below 100 000 HIV-1 RNA copies/mL. The increase in CD4 cell count was significant in both arms (P<0.00001) but the average CD4 cell count at 48 weeks was slightly higher in the nevirapine arm (596 vs. 569; P=0.1588). The number of patients with severe hypertriglyceridaemia (>400 mg/dL) after 48 weeks of treatment decreased in the nevirapine arm (from 11 to six), but increased in the PI arm (from four to 11) and led to treatment discontinuation in two patients. Lipodystrophy changes increased in 15% of patients in the PI arm but decreased in 4% of patients in the nevirapine arm. Finally, although adherence was similar in the two arms, patients reported that it required significantly less effort to stay on treatment in the nevirapine arm. Conclusions The results indicate that switching from PI to nevirapine is as effective as continuing with PI for maintaining viral control, even in patients with baseline viral load above 100,000 copies/mL. In addition, reductions in hypertriglyceridaemia and lipodystrophy and in the effort required to stay on treatment were observed.

Lipid Profiles for Antiretroviral-Naive Patients Starting Pi- and Nnrti-Based Therapy in the Swiss HIV Cohort Study

Background

Blood lipid abnormalities in patients on highly active antiretroviral therapy (HAART) have been associated with exposure to protease inhibitors (PIs), particularly ritonavir. First therapy with a non-nucleoside reverse transcriptase inhibitor (NNRTI) leads to relatively favourable lipid profiles. We report on medium-term lipid profiles (up to 5 years) for antiretroviral-naive patients starting NNRTI- and PI-based HAART in the Swiss HIV Cohort Study.

Methods

Since April 2000, blood samples taken at visits scheduled every 6 months have been analysed for cholesterol and triglyceride concentrations. For 1065 antiretroviral-naive patients starting HAART after April 2000, we estimated changes in concentration over time using multivariate linear regression with adjustment for baseline covariates, use of lipid-lowering drugs and whether the sample was taken in a fasting state.

Results

Non-high density lipoprotein (HDL) cholesterol levels increase with increasing exposure to either PI- or NNRTI-based therapy, HDL cholesterol levels increase and triglyceride levels decrease with increasing exposure to NNRTI-based therapy, whereas triglyceride levels increase with increasing exposure to PI-based therapy. Between NNRTI-based therapies, there is a slight difference in triglyceride levels, which tend to increase with increasing exposure to efavirenz and to decrease with increasing exposure to nevirapine. Of the three common PI-based therapies, nelfinavir appears to have a relatively favourable lipid profile, with little change with increasing exposure. Of the other two PI therapies, lopinavir with ritonavir has a more favourable profile than indinavir with ritonavir, with smaller increases in both non-HDL cholesterol and triglycerides and an increase in HDL cholesterol. Increasing exposure to abacavir is associated with a decrease in the level of triglycerides.

Conclusion

In general, NNRTI-based therapy is associated with a more favourable lipid profile than PI-based therapy, but different PI-based therapies are associated with very different lipid profiles. Nelfinavir appears to have a relatively favourable lipid profile. Of the two boosted PI therapies, lopinavir appears to have a more favourable lipid profile than indinavir.

Substituting abacavir for hyperlipidemia-associated protease inhibitors in HAART regimens improves fasting lipid profiles, maintains virologic suppression, and simplifies treatment

Background

Hyperlipidemia secondary to protease inhibitors (PI) may abate by switching to anti-HIV medications without lipid effects.

Method

An open-label, randomized pilot study compared changes in fasting lipids and HIV-1 RNA in 104 HIV-infected adults with PI-associated hyperlipidemia (fasting serum total cholesterol >200 mg/dL) who were randomized either to a regimen in which their PI was replaced by abacavir 300 mg twice daily (n = 52) or a regimen in which their PI was continued (n = 52) for 28 weeks. All patients had undetectable viral loads (HIV-1 RNA <50 copies/mL) at baseline and were naïve to abacavir and non-nucleoside reverse transcriptase inhibitors.

Results

At baseline, the mean total cholesterol was 243 mg/dL, low density lipoprotein (LDL)-cholesterol 149 mg/dL, high density lipoprotein (HDL)-cholesterol 41 mg/dL, and triglycerides 310 mg/dL. Mean CD4+ cell counts were 551 and 531 cells/mm³ in the abacavir-switch and PI-continuation arms, respectively. At week 28, the abacavir-switch arm had significantly greater least square mean reduction from baseline in total cholesterol (-42 vs -10 mg/dL, P < 0.001), LDL-cholesterol (-14 vs +5 mg/dL, P = 0.016), and triglycerides (-134 vs -36 mg/dL, P = 0.019) than the PI-continuation arm, with no differences in HDL-cholesterol (+0.2 vs +1.3 mg/dL, P = 0.583). A higher proportion of patients in the abacavir-switch arm had decreases in protocol-defined total cholesterol and triglyceride toxicity grades, whereas a smaller proportion had increases in these toxicity grades. At week 28, an intent-to treat: missing = failure analysis showed that the abacavir-switch and PI-continuation arms did not differ significantly with respect to proportion of patients maintaining HIV-1 RNA <400 or <50 copies/mL or adjusted mean change from baseline in CD4+ cell count. Two possible abacavir-related hypersensitivity reactions were reported. No significant changes in glucose, insulin, insulin resistance, C-peptide, or waist-to-hip ratios were observed in either treatment arm, nor were differences in these parameters noted between treatments.

Conclusion

In hyperlipidemic, antiretroviral-experienced patients with HIV-1 RNA levels <50 copies/mL and CD4+ cell counts >500 cells/mm³, substituting abacavir for hyperlipidemia-associated PIs in combination antiretroviral regimens improves lipid profiles and maintains virologic suppression over a 28-week period, and it simplifies treatment.

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

BACKGROUND

Once daily (QD) dosing facilitates regimen simplification and adherence to antiretroviral therapy. Emtricitabine (FTC) QD is a newly approved nucleoside reverse transcriptase inhibitor compared in this study to twice daily lamivudine (3TC BID).

METHODS

Controlled, open label equivalence trial of 440 HIV-1-infected patients with plasma HIV-1 RNA stably suppressed on a regimen of 3TC 150 mg BID, stavudine or zidovudine, and a protease inhibitor or non-nucleoside reverse transcriptase inhibitor. Patients were randomized to continue their current regimen or replace 3TC with FTC 200 mg QD. If HIV-1 RNA levels were </= pound 400 copies/ml at 48 weeks in Protocol 303, patients could continue on FTC in Protocol 350. The primary analysis was based on virologic failure and response defined by plasma HIV-1 RNA suppression below 400 copies/ml.

RESULTS

At baseline, the mean CD4 cell count was 525 (FTC) and 533 x 10(6) cells/l (3TC). At week 48 in Protocol 303, the probability of virologic failure was low, 7% (FTC) and 8% (3TC), and the probability of sustained viral suppression at week 48 was equivalent between treatment arms at both the 50 and 400 copies/ml thresholds. The mean increase in CD4+ T-cell percentage was 2.5% (FTC) and 1.7% (3TC). In Protocol 350, the probability of virologic failure was 11% after 4 years on FTC-containing highly active antiretroviral therapy (HAART).

CONCLUSION

In stably suppressed patients, 200 mg emtricitabine QD was equivalent to 150 mg lamivudine BID. Emtricitabine-containing HAART was associated with a high rate of sustained virologic suppression during 4 years of follow-up.

The Problems Faced When Assessing the Prevalence and Incidence of Antiretroviral-Related Toxicities

Although the dramatic effect of highly active antiretroviral therapy (HAART) in reducing morbidity and mortality must not be underestimated, it is also important to consider the incidence and prevalence of HAART-related toxicities. Although several studies have investigated HAART-related toxicities, there has been great variety between them in the reported incidence and prevalence rates of these toxicities. Various factors, including whether the study type was a clinical trial or an observational study, the definition of the toxicity endpoints, the demographic characteristics of the study populations and the effect of calendar year on analyses, may all influence the rates observed. We investigated the possible explanations for the differences in the incidence and prevalence rates of HAART-related toxicities between studies, focussing on metabolic and hepatotoxic disorders.

Lipodystrophy in Patients with HIV-1 Infection: Effect of Stopping Protease Inhibitors on Tnf-α and Tnf-Receptor Levels, and on Metabolic Parameters

Objective

To evaluate the effects of stopping treatment with protease inhibitors (PIs) on tumour necrosis factor (TNF)-α and TNF-receptor levels, and on the metabolic and morphological abnormalities seen in patients with lipodystrophy.

Design

Longitudinal study.

Methods

Ten HIV-positive patients with lipodystrophy (LD) were studied whilst on PIs (LD1) and 3 months after stopping PIs (LD2) together with 10 HIV-positive subjects on PIs without LD (controls). TNF-α and TNF-receptor levels, insulin resistance parameters, lipid and hormonal profiles, body composition and fat distribution were measured in all subjects.

Results

TNF-α, TNF-receptor I (-RI) and TNF-RII levels were significantly lower in controls ( P=0.02) than in subjects with LD, and there was a significant decrease in TNF-RI and TNF-RII levels ( P=0.01 and 0.03, respectively) on stopping PIs. Insulin levels and the homeostasis model assessment for insulin resistance (HOMA-IR) index were significantly higher in LD1 subjects ( P=0.02) than in controls but did not alter when PIs were stopped. Bioelectrical impedance analysis showed a significant decrease on stopping PIs but CT scans showed no significant difference in fat distribution. Apart from high-density lipoprotein, there was no change in lipid parameters on stopping PIs. There was no difference in the level of testosterone, sex hormone binding globulin and cortisol between the three groups.

Conclusion

Our results show that TNF-α activity in patients with LD is modulated by PIs. This was not accompanied by significant changes in body habitus or insulin resistance, although this may have been a consequence of the short follow-up in this study.

Management of Dyslipidaemia in HIV-Infected Patients Receiving Antiretroviral Therapy

Dyslipidaemia associated with the treatment of HIV infection, particularly with the use of protease inhibitors (PIs), can raise cholesterol and triglyceride (TG) levels to the thresholds indicated for intervention. Recent evidence from epidemiological studies has shown that there are correlations between antiretroviral drug use and increased risks for, and incidences of, cardiovascular disease, including myocardial infarction and coronary heart disease. The primary goals of dyslipidaemia therapy for HIV patients are reductions of both low-density lipoprotein cholesterol (LDL-C) and markedly elevated TG levels. Dietary strategies and exercise programs may be tried, although these have shown inconsistent results. The two options for drug therapy are switching anti-retroviral agents and using lipid-lowering drugs. Each approach is associated with advantages and limitations, and the need to maintain viral suppression must be balanced with the need to treat abnormal lipid levels. Most drug switches replace the PI component with drugs from another antiretroviral class. Selection of drug therapy for lipid lowering depends on the type of dyslipidaemia predominating and the potential for drug interactions. The use of the statins pravastatin and atorvastatin is recommended for the treatment of patients with elevated LDL-C levels and gemfibrozil or fenofibrate for patients with elevated TG concentrations. Development of new PIs with more favourable effects on the lipid profile should be of benefit.

AZT enhances osteoclastogenesis and bone loss

A variety of metabolic complications have been reported to be associated with highly active antiretroviral therapy (HAART), including osteopenia and osteoporosis. In this study, we determine the effects of zidovudine (AZT), a nucleoside reverse transcriptase inhibitor, on osteoclastogenesis in a cultured mouse macrophage preosteoclast cell line (RAW264.7), in mouse primary bone marrow macrophage-monocyte precursors, and on bone mineral density in mice. The results indicate that AZT induces an increase in osteoclastogenesis in the mouse preosteoclast cell line and in mouse bone marrow osteoclast precursors in the presence of RANKL. This increased osteoclastogenesis is dependent upon the concentration of AZT. AZT increases the promoter activity of tartrate-resistant acid phosphatase (TRAP) and the binding and function of the nuclear transcription protein, NF-kappaB, in RAW264.7 cells. Therefore, the effect of AZT is mediated, at least in part, by enhancing RANKL-mediated osteoclastogenesis. Bone mineral density (BMD) in AZT-treated mice is decreased and histopathology shows marked osteopenia. These results support an important role of AZT-stimulated osteoclastogenesis in HAART-induced osteopenia.

Substitution of nevirapine, efavirenz, or abacavir for protease inhibitors in patients with human immunodeficiency virus infection

BACKGROUND

We assessed the strategy of substituting nevirapine, efavirenz, or abacavir for a protease inhibitor in patients infected with human immunodeficiency virus type 1 (HIV-1) in whom virologic suppression had been achieved.

METHODS

We randomly assigned 460 adults who were taking two nucleoside reverse-transcriptase inhibitors and at least one protease inhibitor and whose plasma HIV-1 RNA levels had been less than 200 copies per milliliter for at least the previous six months to switch from the protease inhibitor to nevirapine (155 patients), efavirenz (156), or abacavir (149). The primary end point was death, progression to the acquired immunodeficiency syndrome, or an increase in HIV-1 RNA levels to 200 copies or more per milliliter.

RESULTS

At 12 months, the Kaplan-Meier estimates of the likelihood of reaching the end point were 10 percent in the nevirapine group, 6 percent in the efavirenz group, and 13 percent in the abacavir group (P=0.10 according to an intention-to-treat analysis). HIV-1 RNA could be amplified in 21 of the 29 patients in whom virologic failure developed during treatment with study medication (72 percent), and resistance mutations to the study medication and to at least one of the nucleoside reverse-transcriptase inhibitors in the regimen that failed were detected in all but 1 of the 21 patients. Twenty-three of the 29 patients with virologic failure during treatment with study medication had received prior suboptimal therapy with nucleoside reverse-transcriptase inhibitors. Fewer patients in the abacavir group (6 percent) than in the nevirapine group (17 percent) or the efavirenz group (17 percent) discontinued the study medication because of adverse events (P=0.01). The proportion of patients with fasting lipid levels warranting therapeutic intervention decreased significantly in the abacavir group, but the prevalence of clinical lipodystrophy did not change significantly in the three groups.

CONCLUSIONS

When therapy was switched from a protease inhibitor to nevirapine, efavirenz, or abacavir in patients with virologic suppression, there was a trend toward a higher rate of virologic failure among those given abacavir.

Restoration of human immunodeficiency virus-1-specific responses in patients changing from protease to non-nucleoside reverse transcriptase inhibitor-based antiretroviral therapy

The effect of altering antiretroviral therapy (ART) on responses to viral, recall and human immunodeficiency virus (HIV)-1-specific recombinant antigens and interleukin-2 (IL-2) in HIV-1-infected patients was assessed. A longitudinal cohort study in eight HIV-1 infected individuals following a clinically indicated therapy change (seven for drug intolerance and one for virological failure) from protease inhibitor (PI) to non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral regimens was performed. CD4 T-cell counts, viral loads, lymphoproliferative responses, cytokine production and latent proviral deoxyribonucleic acid (DNA) were measured at baseline and at weeks 12 and 24 after therapy substitution. Following therapy-switch there was a 33% proportional increase in mitogen response (95% confidence interval (CI), 3-33%) and a 31% increase (95% CI, 15-48%) in viral and recall-antigen responses. Six patients developed proliferative responses to low concentration IL-2 stimulation. All patients demonstrated an increase in median HIV-1-specific responses, as three had detectable virus at baseline (two being viral rebound); this may reflect an autovaccination effect. Proviral DNA changes largely reflected plasma HIV-1 ribonucleic acid (RNA). In conclusion, NNRTI substitution for a PI may favour immune reconstitution with an improvement in HIV-1-specific responses, which may reflect differential effects on antigen processing and presentation, an autovaccination effect or alternatively a potential suppressive effect of the PI.

Lipid profiles associated with antiretroviral drug choices

PURPOSE OF REVIEW

In this review we will discuss the recent finding that different drug classes/antiretroviral therapy regimens may differ importantly with respect to their effect on the plasma lipid profile. On the basis of this we will illustrate how such differences, together with knowledge of the presence of other classic coronary artery disease risk factors, open the door for individualized treatment based on criteria in addition to the HIV-1 viral load and CD4 cell count.

RECENT FINDINGS

A large proportion of patients using protease inhibitor-based therapy develop insulin resistance and elevated plasma concentrations of LDL-cholesterol, total cholesterol and triglycerides, which has raised the concern that HIV-infected patients treated with antiretroviral therapy may be at an increased risk of developing premature coronary artery disease. Recent findings suggest that the use of non-nucleoside reverse transcriptase inhibitor-based therapy, in particular nevirapine, results in an elevation in HDL-cholesterol, which may be associated with a decreased incidence of coronary artery disease.

SUMMARY

It is becoming increasingly important to carry out an adequate coronary artery disease risk assessment in each patient both before and approximately annually after the initiation of antiretroviral therapy. In patients with an already considerable risk of coronary artery disease based on traditional risk factors, particularly when it is expected to be difficult to modify these, starting with either a triple nucleoside reverse transcriptase inhibitor or a non-nucleoside reverse transcriptase inhibitor-based regimen may be the preferred option, given the propensity of such regimens to have either no effect or potentially even beneficial effects on the lipoprotein profile.

Effects of Metformin Or Gemfibrozil on the Lipodystrophy of HIV-Infected Patients Receiving Protease Inhibitors

Background

Hypertriglyceridaemia and insulin resistance are common in HIV-infected patients treated with protease inhibitors, particularly in those with lipodystrophy. Whether a therapeutic approach addressed to those metabolic abnormalities may have any impact on body fat is not clear.

Methods

Patients on stable antiretroviral therapy containing protease inhibitors, with abdominal obesity defined by increased waist-to-hip ratio, and plasma triglycerides >200 mg/dl, were randomized to receive blind medication consisting of metformin 850 mg, gemfibrozil 600 mg or placebo every 12 h for 1 year. Weight, height, waist and hip were measured, and fasting blood analyses, including at least CD4 cell count, plasma HIV-1 RNA, lactate, glucose, insulin, triglycerides, total, HDL and LDL cholesterol were performed at baseline and every 3 months. An oral glucose tolerance test, and assessments of total and regional fat by bioimpedance analysis and sonography, respectively, were also done at baseline, 6 and 12 months.

Results

One-hundred-and-eight patients were randomized to placebo ( n=36), gemfibrozil ( n=37) or metformin ( n=35). There was absolute loss of total and regional fat in the three arms without significant changes in the waist-to-hip ratio. However, the loss of fat in patients on gemfibrozil was significantly lower than in patients on placebo. No patient discontinued study drugs due to adverse effects.

Conclusion

In this population of HIV-infected patients, there was a loss of fat along time. The finding of relative preservation of fat associated with gemfibrozil therapy deserves further investigation in the search of potential effective therapies for lipodystrophy in HIV-infected subjects.