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PubMed2004

Human immunodeficiency virus type 1 (HIV-1) integrase: resistance to diketo acid integrase inhibitors impairs HIV-1 replication and integration and confers cross-resistance to L-chicoric acid.

The diketo acids are potent inhibitors of human immunodeficiency virus (HIV) integrase (IN). Mutations in IN, T66I, S153Y, and M154I, as well as T66I-S153Y and T66I-M154I double mutations, confer resistance to diketo acids (D. J. Hazuda et al., Science 287:646-650, 2000). The effects of these IN mutations on viral replication, enzymatic activity, and susceptibility to other HIV inhibitors are reported herein. By immunofluorescence assay and real-time PCR, all mutant viruses demonstrated a modest delay in viral spread compared to that of reference HIV. These viruses also showed a statistically significant defect in integration without defects in reverse transcription. Recombinant IN containing S153Y, T66I, and M154I-T66I mutations had an approximately twofold decrease in both disintegration and 3'-end-processing-strand transfer activities in vitro. In contrast, IN containing M154I demonstrated a greater than twofold increase in specific activity in both reactions. All mutant HIVs were resistant to l-chicoric acid, a dicaffeoyltartaric acid IN inhibitor, both in tissue culture and in biochemical assays, yet remained susceptible to the reverse transcriptase inhibitors zidovudine and nevirapine. Thus, IN mutations conferring resistance to the diketo acids can yield integration defects, attenuated catalysis in vitro, and cross-resistance to l-chicoric acid.

Caffeic Acids↗

PubMed2005

Long term probability of detection of HIV-1 drug resistance after starting antiretroviral therapy in routine clinical practice.

BACKGROUND: Little is known about the long term risk of development of HIV-1 drug resistance for patients starting antiretroviral therapy (ART) with three or four drug regimens in routine clinical practice. METHODS: We analysed a large cohort study of patients seen in one of six large HIV clinics in and around London, UK. The focus of this analysis was on patients who started ART with two nucleosides plus either a single protease inhibitor (PI), a PI with ritonavir, abacavir or a non-nucleoside reverse transcriptase inhibitor (NNRTI). RESULTS: 4306 patients were followed; 1436 (33%) started with a single PI, 279 (6%) with a PI plus ritonavir, 156 (4%) with triple nucleosides and 2435 (57%) with an NNRTI. The overall cumulative risk of viral load failure was 38% by 6 years. Risk of > or =1 major IAS-USA mutation was 27% by 6 years; risk of mutations from at least two of the three main drug classes was 20% over the same period. These are lower limit estimates as test results were not available for many with viral load failure. Risk of PI mutations being detected in people who started ART with regimens containing a PI with ritonavir was significantly lower than the risk of NNRTI mutations being detected in those starting with NNRTI-containing regimens (relative hazard 0.3195% CI 0.15-0.61; p = 0.0008). CONCLUSION: In routine practice, rates of viral load failure and of resistance detection in patients who started ART with three or four drugs are appreciable.

Adult↗

PubMed2005

Impact of HIV and highly active antiretroviral therapy on leukocyte adhesion molecules, arterial inflammation, dyslipidemia, and atherosclerosis.

Highly active antiretroviral therapy (HAART) has greatly extended the lives of people infected with the human immunodeficiency virus (HIV). This reduced risk of early death from opportunistic infections or other sequelae of HIV infection, however, means that other possible causes of death emerge. Myocardial infarction has become a matter of particular concern. Two of the main sources of cardiovascular disease in this population are believed to be vascular inflammation and dyslipidemia. We review the evidence for this hypothesis and discuss the relationship of HIV to vascular inflammation. Current treatment guidelines do not recommend the immediate initiation of HAART unless warranted, potentially allowing long-term, unchecked viral impact on the development of atherosclerosis. Finally, we consider the protease inhibitors traditionally included in HAART regimens and their relationship to the development of dyslipidemia, as well as other classes of antiretrovirals, such as the non-nucleoside reverse transcriptase inhibitors, which might be a better choice for patients with cardiovascular risks. Other strategies, such as pharmacologic, nutritional, and physical activity interventions are discussed. The patients who might benefit most are those in whom the precursors of vascular plaques, such as fatty streak, smooth muscle cell, macrophage, and T-lymphocyte aggregation not yet identified by echocardiographic and biopsy findings have already developed as a result of unchecked viral inflammation and replication.

Antiretroviral Therapy, Highly Active↗

PubMed2003

Reconstitution of thymic function in HIV-1 patients treated with highly active antiretroviral therapy.

The extent to which highly active antiretroviral therapy can restore thymic function in HIV-1 infected patients is not known. We simulate treatment using a temporal model of thymopoiesis during HIV-1 infection, tracking thymic function by the number of recent thymic emigrants (RTE) exported to the periphery per day. Our results suggest that suppressing viral load in peripheral blood and improving inherent thymic function are necessary for the reconstitution of RTE levels in adult thymic infection with either R5 or X4 HIV-1 strains. This is also the case in pediatric thymic infection with R5 strains. However, recovery of RTE levels during pediatric infection with X4 strains also depends on high drug efficacy within the thymus. We further predict that protease inhibitors have high levels of efficacy directly suppressing viral replication within the thymus, while reverse transcriptase inhibitors have low efficacy.

Adult↗

PubMed2004

[Recent progress in anti-HIM-1 research].

Establishment of highly active antiretroviral therapy (HAART) has brought about dramatic improvement of the prognosis of HIV-1 infection. On the other hand, several drawbacks associated with long-term HARRT have been demonstrated. Among them, emergence of drug-resistant viruses is a serious problem; therefore compounds with novel mechanisms of action have been investigated to overcome the problem. Novel reverse transcriptase inhibitors (RTIs) and protease inhibitors (PIs) recently approved for clinical use are effective against existing resistant strains by once daily administration. In addition, the virus entry (fusion) inhibitor has also been licensed. Since this compound targets a molecule other than reverse transcriptase and protease for inhibition of HIV-1 replication, it is active against HIV-1 highly resistant to RTIs and PIs. Furthermore, clinical trials with CCR 5 (coreceptor of HIV-1) antagonists are in progress, and inhibitors of integrase, HIV-1 gene expression, and virion assembly have been identified.

Anti-HIV Agents↗

PubMed1996

Principal components describing biological activities and molecular diversity of heterocyclic aromatic ring fragments.

Ten physicochemical variables have been calculated for each of 100 different aromatic rings. These variables were selected because of their potential involvement in the molecular recognition of drug-receptor binding interactions, and they include size, lipophilicity, dipole magnitude and orientation, HOMO and LUMO energies, and electronic point charges. A total of 59 different aromatic ring systems were studied including monocyclics and [5.5]-, [6.5]- and [6.6]-fused bicyclics. A principal components analysis of b1ese results generated four principal components which account for 84% of the total variance in the data. These principal components provide a quantitative measure of molecular diversity, and their relevance for structure-activity relationships is discussed. The principal components correlate with the in vitro biological activity of heterocyclic aromatic fragments within a series of previously reported HIV-1 reverse transcriptase inhibitors.

Chemical Phenomena↗

PubMed2001

Comparison of initial combination antiretroviral therapy with a single protease inhibitor, ritonavir and saquinavir, or efavirenz.

OBJECTIVE: To compare the effectiveness of initial highly active antiretroviral therapy with either: a single protease inhibitor (PI); ritonavir (RTV)/saquinavir (SQV); or efavirenz (EFV) plus nucleoside reverse transcriptase inhibitors. DESIGN: Cohort study. SETTING: Urban HIV clinic. PATIENTS: Five-hundred and forty-five HIV-1-infected individuals with minimal antiretroviral exposure who started combination therapy with > or = 3 antiretroviral drugs and > or = 1 NRTI to which they had not previously been exposed (single PI, 416; RTV/SQV, 68; EFV, 61). MAIN OUTCOME MEASURES: HIV-1 RNA < 400 copies/ml within 8 months of starting therapy; time to HIV-1 RNA rebound to > 1000 copies/ml in the subset of patients achieving initial viral suppression; change in CD4 cell count from baseline within 12 months of starting therapy. RESULTS: By intent-to-treat analysis, initial viral suppression was achieved by 72% of patients in the EFV group, compared to 49% in the single PI group (P = 0.001) and 51% in the RTV/SQV group (P = 0.019). Among patients who achieved initial viral suppression, time to viral rebound was similar in the three groups. Durable viral suppression (> or = 3 consecutive HIV-1 RNA levels < 400 copies/ml for > 6 months) was achieved by 53% of patients in the EFV group, 26% in the single PI group, and 29% in the RTV/SQV group (P < 0.05 for both comparisons with EFV). The median CD4 cell count increase was 139 x 10(6) cells/l, and was similar in the three groups. CONCLUSIONS: In agreement with a recent clinical trial, use of initial EFV-based combination antiretroviral therapy was associated with higher rates of viral suppression than PI-based therapy in a clinical cohort.

Adult↗

PubMed2003

Lactic acidosis in HIV infected patients: a systematic review of published cases.

OBJECTIVE: To describe the clinical, epidemiological, and biochemical characteristics of published cases of lactic acidosis (LA) and to generate hypotheses concerning risk factors associated with this complication. METHODS: Systematic review of cases reported in the medical literature. RESULTS: 217 published cases were identified, 90 of which fulfilled the study definition and had sufficient individual data on potential risk factors to be included. The 90 patients had a mean age of 40.1 years (range 16-69) and 53% were female. All 90 patients were taking nucleoside reverse transcriptase inhibitors (NRTI) at the time of the episode. Among the 83 patients with details of their antiretroviral therapy (ART) regimen 51 patients were taking stavudine, 29 zidovudine, 27 didanosine, and 25 lamivudine. Around 50% of the patients had abdominal pain, nausea, or vomiting. Hepatic steatosis was consistently reported (53/90) and in 36 (68%) there was histological evidence. The case fatality rate was 48%. Six cases were rechallenged with NRTI and three developed a further LA episode. Using data on the numbers of HIV infected individuals receiving care in the United States, we estimate that the risk of LA could be 2.5 times higher for women than men. CONCLUSIONS: NRTI use and female sex appear to be risk factors for the development of LA. What other factors are involved is still not clear but might include duration of NRTI therapy, specific drug use, and genetic predisposition. A case-control study is needed to better define risk factors for severe LA.

Acidosis, Lactic↗

PubMed2004

Practical guidelines to interpret plasma concentrations of antiretroviral drugs.

Several relationships have been reported between antiretroviral drug concentrations and the efficacy of treatment, and toxicity. Therefore, therapeutic drug monitoring (TDM) may be a valuable tool in improving the treatment of HIV-1-infected patients in daily practice. In this regard, several measures of exposure have been studied, e.g. trough and maximum concentrations, concentration ratios and the inhibitory quotient. However, it has not been unambiguously established which pharmacokinetic parameter should be monitored to maintain optimal viral suppression. Each pharmacokinetic parameter has its pros and cons. Many factors can affect the pharmacokinetics of antiretroviral agents, resulting in variability in plasma concentrations between and within patients. Therefore, plasma concentrations should be considered on several occasions. In addition, the interpretation of the drug concentration of a patient should be performed on an individual basis, taking into account the clinical condition of the patient. Important factors herewith are viral load, immunology, occurrence of adverse events, resistance pattern and comedication. In spite of the described constraints, the aim of this review is to provide a practical guide for TDM of antiretroviral agents. This article outlines pharmacokinetic target values for the HIV protease inhibitors amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir and saquinavir, and the non-nucleoside reverse transcriptase inhibitors efavirenz and nevirapine. Detailed advice is provided on how to interpret the results of TDM of these drugs.

Anti-HIV Agents↗

PubMed2003

Long-term efficacy and safety of twice-daily saquinavir soft gelatin capsules (SGC), with or without nelfinavir, and three times daily saquinavir-SGC, in triple combination therapy for HIV infection: 100-week follow-up.

OBJECTIVES: To evaluate the long-term efficacy and safety of saquinavir soft gelatin capsules (SQV-SGC) (Fortovase) in twice-daily, with or without nelfinavir (NFV), and three-times-daily regimens. This was an extension of a 48-week study, with follow-up to 100 weeks. DESIGN: Patients were randomized to one of three treatment arms: arm A, SQV-SGC 1200 mg three times daily plus two nucleoside reverse transcriptase inhibitors (NRTIs); arm B, SQV-SGC 1,600 mg twice daily plus two NRTIs; or arm C, SQV-SGC 1200 mg twice daily plus NFV 1250 mg twice daily plus one NRTI. At week 48, patients could either withdraw or continue in the study to the common study closure date. Antiretroviral activity was assessed by changes in HIV-1 RNA values and CD4 cell counts from 48 weeks until 100 weeks. RESULTS: In the modified intention-to-treat population, the proportion of patients with HIV-1 RNA values <400 copies/ml was statistically different between arms A and C (49 vs 28%, P=0.017), and arms B and C (48 vs 28%, P=0.027). Continued suppression of HIV-1 replication (HIV-1 RNA <400 copies/ml) was observed through 100 weeks in 83% (30/36), 73% (29/40) and 62% (16/26) of patients in treatment arms A, B and C, respectively, in the on-treatment (OT) population. At 100 weeks, sustained increases were achieved in mean CD4 cell counts of +361, +273 and +309 cells/mm3, respectively (OT population). No additional adverse events or increase in the proportion of patients reporting adverse events were observed from 48 weeks to 100 weeks. CONCLUSIONS: This study demonstrates the long-term efficacy and safety of SQV-SGC twice daily, with or without NFV, and three times daily, in triple combination therapy for HIV-1-infected patients. However, the evidence suggests that long-term treatment with SQV-SGC plus NFV may be less acceptable to patients.

Anti-HIV Agents↗

PubMed2002

A prospective comparison of the two main indications of efavirenz in 2001 highly active antiretroviral therapy (HAART) regimens: first-line versus salvage use.

OBJECTIVE: To determine the efficacy of efavirenz introduction in first-line HAART compared with salvage multidrug regimens. PATIENTS AND METHODS: Prospective 15 month comparison of 107 consecutive HIV-infected patients starting efavirenz, according to laboratory and clinical outcome of first-line versus rescue drug use, therapeutic history and association of selected antimicrobial agents: naive patients were compared with nucleoside reverse transcriptase inhibitor (NRTI)-experienced patients in the first group, and patients in the second group who had one or more NRTI changed when starting a rescue treatment containing one or more novel protease inhibitors (PIs) were compared with those who did not. RESULTS: Efavirenz was administered with one or more novel NRTIs to 55 patients (27 antiretroviral-naive and 28 patients experienced with NRTIs only), compared with 52 patients who needed a multidrug salvage regimen after two or more failures of a 15-40 month PI-containing regimen. In an intention-to-treat analysis, con-sidering early interruption or an unsatisfactory virological course as a failure, only one patient on salvage therapy completed a favourable 15 month follow-up, compared with 31 patients experiencing first-line efavirenz-based HAART (P < 0.0001). The immunological response was less affected in both intensity and duration in patients undergoing rescue therapy. While no significant outcome difference was detected in the first group between naive and NRTI-experienced patients, among the salvage subjects the change of one or more NRTIs seemed to significantly improve virological and immunological outcome. Viral genotyping detected at least the K103N mutation in 41% of the 78 evaluable patients, despite lack of exposure to efavirenz and related compounds. Salvage patients had a significantly greater frequency of non-nucleoside RTI (NNRTI) resistance compared with the first-line group (P < 0.0001), in proportion to the extent of mutations affecting other drug classes (P < 0.0001). CONCLUSION: An efavirenz-based initial triple drug HAART proved significantly more effective than efavirenz adjunct to a rescue treatment performed after repeated failures of PI-based regimens. The unsatisfactory response of the salvage group was probably due to diffuse cross-resistance descending from previous therapy, even when NNRTIs were never administered.

Alkynes↗

PubMed1987

Conformational properties of 3'-azido-3'deoxy-thymidine (AZT), an inhibitor of HIV reverse transcriptase.

The low-energy conformations of 3'-azido-3'-deoxy-thymidine, (AZT), an inhibitor of retroviral reverse transcriptase, have been studied by molecular mechanics techniques. A force-field has been developed for the azido group by quantum-mechanical methods, and used in the analysis. The global low-energy structure of AZT has C3'-endo sugar pucker, an anti glycosidic angle, and a g+ C4'-C5' conformation. It is concluded that the AZT molecule has conformational properties that are very similar to those of standard deoxypyrimidines.

Antiviral Agents↗

PubMed2003

Predictors of the virological response to a change in the antiretroviral treatment regimen in HIV-1-infected patients enrolled in a randomized trial comparing genotyping, phenotyping and standard of care (Narval trial, ANRS 088).

OBJECTIVE: To identify predictors of the virological response to antiretroviral therapy in patients in whom initial therapy has failed. METHODS: The Narval trial was designed to compare phenotyping, genotyping and standard of care for the choice of antiretroviral therapy in patients in whom a protease inhibitor (PI)-containing regimen had failed. Virological success was defined as viral load below 200 copies/ml at week 12. Baseline variables including demographic, clinical and biological characteristics, HIV reverse transcriptase and protease mutations, the randomization arm, the drugs prescribed, as well as adherence to treatment and plasma concentrations of PIs and non-nucleoside reverse transcriptase inhibitors (NNRTIs) at week 12 were tested in the model. Variables that were significantly associated with virological success in univariate analysis were included in a logistic regression model. RESULTS: Five-hundred-and-forty-one patients were randomized. Virological success at week 12 was obtained in 200 patients. In multivariate analysis, the following factors were significantly associated with virological success: prescription of efavirenz to NNRTI-naive patients (OR=4.37; 95% CI: 2.76-6.90), randomization to the genotyping arm (OR=2.13, 1.20-3.79), prescription of lamivudine (OR=1.69, 1.01-2.83) and prescription of abacavir to abacavir-naive patients (OR=1.66, 1.02-2.72). Factors significantly associated with virological failure were prescription of nelfinavir (OR=0.30, 0.13-0.68), a high baseline viral load (OR=0.37, 0.28-0.50), the presence of at least five PI mutations (OR=0.42, 0.26-0.66), the presence of at least three thymidine analogue mutations (OR=0.61, 0.39-0.97) and at least 30 months of prior PI exposure (OR=0.64, 0.41-0.99). CONCLUSIONS: These results confirm that among heavily pretreated patients, prescription of efavirenz to NNRTI-naive patients is associated with a good virological response, while a high baseline viral load, a large number of PI mutations and nelfinavir prescription at baseline are associated with a poor virological response. Genotyping was found to be beneficial, while this was not the case for phenotyping. This work was presented at the XI International HIV Drug Resistance Workshop, Sevilla, Spain, July 3-6 2002 (Abstract N(o)133); and at the XIV International Conference on AIDS, Barcelona, Spain, July 7-11 2002 (Abstract N(o)ThOrB138).

Adult↗

PubMedDate not supplied

HIV lipodystrophy: a review.

The dramatic clinical benefit of highly active antiretroviral therapy has been offset, to an extent, by the development of unforeseen long-term toxicities. Of these, the HIV lipodystrophy syndrome is most prominent. The array of related but possibly separate manifestations includes fat deposition and atrophy and metabolic complications such as hyperlipidemias and diabetes mellitus. These have been attributed to the use of protease inhibitors, but other factors may be involved, particularly the use of nucleoside reverse transcriptase inhibitors, especially stavudine. The pathogenesis of any of the manifestations of the syndrome remains to be explained. The metabolic complications may respond to standard treatments, but most therapies directed at fat changes have been unsuccessful. This review will summarize the state of knowledge in the field.

Anti-HIV Agents↗

PubMed2006

Partial treatment interruption of protease inhibitor-based highly active antiretroviral therapy regimens in HIV-infected children.

Treatment guidelines for HIV-infected children recommend using combinations of reverse transcriptase inhibitors (RTIs) and protease inhibitors (PIs). Successful suppression of HIV replication and adherence to these regimens are often suboptimal because of multiple factors. For patients with detectable viremia and limited treatment options, therapy simplification consisting of RTIs, referred to as partial treatment interruption (PTI), may represent a temporizing option. We describe a cohort of 26 HIV-infected children who underwent treatment simplification by discontinuing the PI and continuing therapy with 2 or more RTIs. The subjects, who were identified retrospectively, were followed for a period of 24 to 96 weeks. Data collected included clinical information, viral load, and CD4T lymphocyte percentage (CD4%) at baseline and 24, 48, and 96 weeks after PTI. Twenty-six, 21, and 11 patients were evaluated at 24, 48, and 96 weeks, respectively. No child had Centers for Disease Control and Prevention-defined disease progression, and there were no significant changes in viral loads (P > 0.5) across all study intervals after interruption of the PIs. Although most children maintained a CD4% > 15%, comparisons of CD4% at 24 and 48 weeks demonstrated a statistically significant decrease compared with baseline. Therapy simplification by PTI may provide a practical option in patients intolerant of or failing PI-based highly active antiretroviral therapy.

Adolescent↗

PubMed2006

An update on therapeutic drug monitoring for antiretroviral drugs.

There is an increasing uptake of TDM of antiretroviral drugs, particularly in Europe. There is consensus that current antiretroviral drugs meet most of the criteria of drugs that can be considered as candidates for a TDM strategy. This review examines the pharmacokinetic-pharmacodynamic relationship for protease inibitors and non nucleoside reverse transcriptase inhibitor, give an overview of the published randomised clinical trials and then summarises the scenarios for use of TDM. Finally the development of the inhibitory quotient (IQ) concept is discussed.

Drug Monitoring↗

PubMed2000

Body habitus alterations in HIV-infected women treated with combined antiretroviral therapy.

Fat distribution alterations are among the most frequent and unexpected side effects of combined antiretroviral therapy. They may occur in patients receiving protease inhibitor-containing regimens and those treated with combinations of only nucleoside reverse transcriptase inhibitors. The broad spectrum of body fat alterations, which are variably associated with metabolic abnormalities, raises the question as to whether they represent different components of the same syndrome or are manifestations of different pathogenetic mechanisms. Recent clinical evidence is consistent with a higher risk of developing body fat alterations in females. We here report three different aspects of body habitus changes in women treated with various antiretroviral regimens and describe their short-term follow-up. We also discuss the possible pathogenetic implications and the role of different drug classes according to present knowledge.

Adult↗

PubMed2004

Changes in thrombolytic and inflammatory markers after initiation of indinavir- or amprenavir-based antiretroviral therapy.

HIV-infected subjects who have lipodystrophy and insulin resistance on prolonged antiretroviral therapy have elevated levels of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) antigens, markers of impaired thrombolysis that are associated with hyperinsulinemia and increased cardiovascular risk. We studied HIV-infected, protease inhibitor (PI)-naive adults treated with indinavir (n = 11) or amprenavir (n = 14) plus two nucleoside reverse transcriptase inhibitors enrolled in two independent prospective trials. Antiretroviral and immune responses were similar in both studies. Over 8 wk, indinavir was associated with decreased insulin sensitivity, whereas amprenavir was not. Levels of tPA antigen declined by approx 25% with both treatments (p < 0.05 for each); levels of PAI-1 antigen did not change. Levels of the inflammatory marker soluble tumor necrosis factor-alpha receptor II (sTNFr2) correlated positively with tPA antigen (r = 0.33, p = 0.02), and mean (SD) plasma concentrations of sTNFr also declined with treatment (4.44 +/- 1.11 ng/mL pretherapy, 3.75 +/- 1.21 posttherapy, p = 0.007). Short-term improvement in a marker of impaired thrombolysis and increased vascular risk can occur during PI-based antiretroviral therapy, perhaps as a consequence of improvement in HIV-related inflammation. This improvement occurred independent of development of insulin resistance, which occurred only with indinavir.

Adult↗