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PubMed2001

Improvement of HAART-associated insulin resistance and dyslipidemia after replacement of protease inhibitors with abacavir.

OBJECTIVE: To assess the effect of replacing protease inhibitors (PIs) with abacavir on insulin sensitivity and plasma lipids. - DESIGN: Pilot study including 31 patients with sustained virological control on their first PI-containing HAART regimen. 16 patients were switched from PIs to abacavir (ABC group), 15 patients continued on PIs (PI group). In all patients, nucleoside-analogue reverse transcriptase inhibitors were continued. METHODS: Insulin sensitivity (using an intravenous insulin tolerance test) and fasting total cholesterol and triglycerides were determined at baseline, month 3, 6, 9 and 12. RESULTS: In the ABC group, there was a significant increase in median insulin sensitivity from baseline within 6 months (+ 49 micromol/l/min), and a significant decrease in both triglycerides (-41mg/dl) and cholesterol (-40mg/dl) at month 3. These changes were sustained through month 12. In addition, a reversal of baseline insulin resistance, hypercholesterolemia and hypertriglyceridemia was observed in the majority of patients. In the PI group, no significant changes in insulin sensitivity, triglycerides and cholesterol were observed. There was a significant correlation between the changes in insulin sensitivity, triglycerides and cholesterol. INTERPRETATION: Switching from PIs to abacavir is associated with an improvement of insulin sensitivity and a decrease of cholesterol and triglycerides in the majority of patients with HAART-associated metabolic alterations and therefore might be an alternative for patients to PI-containing HAART regimens.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Structural characterization of HIV reverse transcriptase: a target for the design of specific virus inhibitors.

The reverse transcriptase (RT) of HIV is an important target for chemotherapy as demonstrated by the effective treatment of AIDS patients with zidovudine, a potent inhibitor of RT. Structural studies of HIV RT were therefore undertaken with a view to designing more effective inhibitors. To obtain sufficient quantities of enzyme for these studies the reverse transcriptase gene of HIV was cloned into a high level expression plasmid yielding reverse transcriptase at a level of 10% of the total Escherichia coli proteins. Monoclonal antibodies to RT were raised in mice and have been used to purify the enzyme by immunoaffinity chromatography. Crystallization of the enzyme has been achieved and studies are underway to determine its three-dimensional structure. In addition, carboxy-terminal truncated mutants were prepared by inserting stop codons into the gene at appropriate sites. The proteins expressed were analysed for RT and RNase H activity and used for mapping RT epitopes. This, together with previous data on site-directed mutagenesis of conserved regions of HIV RT has helped to map some of the structural and functional regions of the enzyme.

Animals↗
PubMed1999

Synthesis of 5,8-dimethoxy-3-hydroxy-4-quinolone, a reported inhibitor of HIV RT, and evidence the original proposed structure was incorrect.

An unambiguous total synthesis of the title compound, a semi-synthetic derivative reported to be a non-nucleoside reverse transcriptase inhibitor, was conducted in four steps from 2,5-dimethoxyaniline. The synthetic material differed from that reported in the literature, both in its physical properties and 1H NMR spectrum. Biological evaluation indicated that synthetic 2 was inactive against HIV-1 RT, suggesting that the previous structural assignment of the semi-synthetic derivative was incorrect.

HIV Reverse Transcriptase↗
PubMed2000

Efavirenz: new preparation. An alternative to HIV protease inhibitors.

(1) Efavirenz, a non nucleoside HIV reverse transcriptase inhibitor, is indicated, in combination with other antiretroviral drugs, for the treatment of HIV infection. (2) The methodologically sound clinical file is limited to trials based on validated surrogate end points (viral load) and involving patients in the early stages of HIV infection. (3) Two dose-finding studies favour a dose regimen of 600 mg in a single daily intake for adults. (4) Interim results of three ongoing trials are also available. After 48 weeks of treatment, three-drug regimens comprising efavirenz plus two nucleoside inhibitors were more effective on viral load than three-drug regimens comprising indinavir plus two nucleoside inhibitors. In another trial, after 24 weeks of treatment, a three-drug regimen combining efavirenz and two nucleoside inhibitors was no more effective on viral load than a three-drug regimen comprising nelfinavir and two nucleoside inhibitors. (5) It remains to be determined if four-drug regimens comprising efavirenz, a protease inhibitor and two nucleoside inhibitors are superior to three-drug regimens. (6) Data on the safety profile of efavirenz show mainly neuropsychological and cutaneous disorders. The severity of cutaneous effects in children needs further assessment.

Anti-HIV Agents↗
PubMed2006

Long-term survival and immuno-virological response of African HIV-1-infected children to highly active antiretroviral therapy regimens.

BACKGROUND: In Africa, facing the scaling-up of HAART, there is an urgent need to monitor accurately the long-term benefits of these lifelong treatments. METHODS: Survival and immuno-virological response were assessed for 78 children in the ANRS 1244/1278 Children's cohort (Abidjan, Côte d'Ivoire) who were enrolled from October 2000 for treatment with HAART and followed to September 2004. Initial HAART consisted of two nucleoside reverse transcriptase inhibitors with either nelfinavir (NFV) or efavirenz (EFV). For the comparison of immunological and virological responses, CD4 cell counts and HIV-1 RNA viral load were assessed by performing time-point specific and longitudinal data analysis. RESULTS: At baseline, the median CD4 cell percentage was 7.5% and the median HIV-1 RNA viral load was 5.37 log10 copies/ml. The survival probability was high (0.86 at month 42; 95% confidence interval, 0.77-0.92) with no difference according to whether the HAART regimen contained NFV or EFV. At 36 and 42 months of follow-up, an immune recovery was observed with median CD4 cell percentages reaching 23.1% and 24.8%, respectively, with no difference according to the HAART regimen (longitudinal data analysis). At the same time points, a sustained viral suppression was also obtained, with undetectable viral load achieving in 46.5% and 45.0%, respectively, regardless of whether the HAART regimen. CONCLUSION: This study demonstrates the durability of both clinical and biological response to HAART in African children.

Adolescent↗
PubMed2006

The level of persistent HIV viremia does not increase after successful simplification of maintenance therapy to lopinavir/ritonavir alone.

OBJECTIVE: To determine whether the level of persistent HIV-1 viremia is affected by simplifying standard antiretroviral therapy to lopinavir/ritonavir (LPV/r) alone. DESIGN: Measurement of HIV-1 RNA levels < 50 copies/ml in longitudinal plasma samples from 41 of 42 subjects enrolled in the 'Only Kaletra' study that compared maintenance therapy with LPV/r alone to standard of care (SOC) with two nucleoside reverse transcriptase inhibitors (NRTI) and LPV/r. METHODS: Plasma samples for each subject from study screening to week 48 were tested using a modified Roche Amplicor HIV-1 RNA assay with a quantification limit of 3 copies/ml. RESULTS: Median plasma HIV-1 RNA values at baseline and weeks 4, 8, 12, 24 and 48 were not significantly different between the LPV/r alone and the SOC arms, being 5.1 versus 3.0 (P = 0.29), 4.5 versus 2.9 (P = 0.44), 3.3 versus 2.9 (P = 0.99), 1.9 versus 1.0 (P = 0.68), 3.7 versus 3.6 (P = 0.49), and 2.8 versus 1.6 copies/ml (P = 0.78), respectively. In the 17 of 21 subjects who maintained virus suppression < 50 copies/ml on LPV/r alone, median HIV-1 RNA values did not increase significantly from baseline at any time point after discontinuing NRTI, in comparison to the three subjects with virologic failure whose median HIV-1 RNA levels began to rise at week 8. CONCLUSIONS: The level of persistent viremia did not increase after stopping NRTI therapy among subjects who maintained virus suppression < 50 copies/ml on LPV/r alone through 48 weeks. This supports further studies of induction-simplification therapy for treatment of HIV-1 infection including the identification of factors predicting success or failure of simplified therapy.

Drug Resistance, Viral↗
PubMed2001

Susceptibility of the porcine endogenous retrovirus to reverse transcriptase and protease inhibitors.

Porcine xenografts may offer a solution to the shortage of human donor allografts. However, all pigs contain the porcine endogenous retrovirus (PERV), raising concerns regarding the transmission of PERV and the possible development of disease in xenotransplant recipients. We evaluated 11 antiretroviral drugs licensed for human immunodeficiency virus type 1 (HIV-1) therapy for their activities against PERV to assess their potential for clinical use. Fifty and 90% inhibitory concentrations (IC(50)s and IC(90)s, respectively) of five nucleoside reverse transcriptase inhibitors (RTIs) were determined enzymatically for PERV and for wild-type (WT) and RTI-resistant HIV-1 reference isolates. In a comparison of IC(50)s, the susceptibilities of PERV RT to lamivudine, stavudine, didanosine, zalcitabine, and zidovudine were reduced >20-fold, 26-fold, 6-fold, 4-fold, and 3-fold, respectively, compared to those of WT HIV-1. PERV was also resistant to nevirapine. Tissue culture-based, single-round infection assays using replication-competent virus confirmed the relative sensitivity of PERV to zidovudine and its resistance to all other RTIs. A Gag polyprotein-processing inhibition assay was developed and used to assess the activities of protease inhibitors against PERV. No inhibition of PERV protease was seen with saquinavir, ritonavir, indinavir, nelfinavir, or amprenavir at concentrations >200-fold the IC(50)s for WT HIV-1. Thus, following screening of many antiretroviral agents, our findings support only the potential clinical use of zidovudine.

Amino Acid Sequence↗
PubMed2002

Rates of combination antiretroviral treatment change in Australia, 1997-2000.

OBJECTIVE: To estimate the rate of combination antiretroviral treatment change and factors associated with combination antiretroviral treatment change among patients recruited in the Australian HIV Observational Database (AHOD). METHODS: Analyses were based on patients in the AHOD who had commenced combination antiretroviral treatment after 1 January 1997. Combination antiretroviral treatment change was defined as the addition or change of at least one antiretroviral drug. A random-effect Poisson regression model was used to assess factors associated with increased rates of combination antiretroviral treatment change. RESULTS: A total of 596 patients in the AHOD were included in the analysis, with a median follow-up of 2.3 years. The overall rate of antiretroviral treatment change in this group was 0.45 combinations per year. In a multivariate analysis, a low CD4 count (< 200 cells/microL) at baseline was associated with an increased rate of treatment change [rate ratio (RR)=1.43; 95% confidence interval (CI), 1.13, 1.80; P=0.003)]. Combinations including a nonnucleoside reverse transcriptase inhibitor were also associated with slower rates of change than treatment combinations including a protease inhibitor (RR=0.64, 95% CI, 0.51, 0.80, P < 0.001). CONCLUSION: Initiating combination antiretroviral at a CD4 cell count < 200 cells/microL may be associated with poorer patient outcomes. However, the possibility that clinician or patient concerns about low immunological status led to faster rates of treatment change in this group cannot be discounted.

Adult↗
PubMed2002

The metabolic activation of abacavir by human liver cytosol and expressed human alcohol dehydrogenase isozymes.

Abacavir (ZIAGEN) is a reverse transcriptase inhibitor marketed for the treatment of HIV-1 infection. A small percentage of patients experience a hypersensitivity reaction indicating immune system involvement and bioactivation. A major route of metabolism for abacavir is oxidation of a primary betagamma unsaturated alcohol to a carboxylic acid via an aldehyde intermediate. This process was shown to be mediated in vitro by human cytosol and NAD, and subsequently the alphaalpha and gamma2gamma2 human isoforms of alcohol dehydrogenase (ADH). The alphaalpha isoform effected two sequential oxidation steps to form the acid metabolite and two isomers, qualitatively reflective of in vitro cytosolic profiles. The gamma2gamma2 isozyme generated primarily an isomer of abacavir, which was minor in the alphaalpha profiles. The aldehyde intermediate could be trapped in incubations with both isozymes as an oxime derivative. These metabolites can be rationalized as arising via the aldehyde which undergoes isomerization and further oxidation by the alphaalpha enzyme or reduction by the gamma2gamma2 isozyme. Non-extractable abacavir protein residues were generated in cytosol, and with alphaalpha and gamma2gamma2 incubations in the presence of human serum albumin (HSA). Metabolism and residue formation were blocked by the ADH inhibitor 4-methyl pyrazole (4-MP). The residues generated by the alphaalpha and gamma2gamma2 incubations were analyzed by SDS-PAGE with immunochemical detection. The binding of rabbit anti-abacavir antibody to abacavir-HSA was shown to be dependent on metabolism (i.e. NAD-dependent and 4-MP sensitive). The mechanism of covalent binding remains to be established, but significantly less abacavir-protein residue was detected with an analog of abacavir in which the double bond was removed, suggestive of a double bond migration and 1,4 addition process.

Alcohol Dehydrogenase↗
PubMed2004

Impact of indinavir on the quality of life in patients with advanced HIV infection treated with zidovudine and lamivudine.

OBJECTIVE: In AIDS Clinical Trial Group (ACTG) study 320, triple-combination antiretroviral therapy including indinavir significantly slowed progression to acquired immunodeficiency syndrome or death, compared with treatment with dual nucleoside reverse-transcriptase inhibitors (NRTIs) alone, in zidovudine-experienced patients with advanced human immunodeficiency virus (HIV) infection. We examined the impact of indinavir on quality of life in participants from this study. METHODS: A total of 1156 protease inhibitor- and lamivudine-naive patients stratified by CD4 cell count (<or=50 and 51-200 cells/mm(3)) were randomized to receive zidovudine (or stavudine) and lamivudine, with or without indinavir. Health-related quality of life was measured using the ACTG QoL601-602 questionnaire, which assesses general health status measured on a visual analogue scale and 8 specific health-related domains. Quality-adjusted survival time was estimated using the visual analogue scale for general health. RESULTS: Mean changes in general health scores after 24 weeks were +2.9 in the triple-therapy group versus -0.2 in the dual-therapy group (P=.018). By week 24, scores in all specific domains were higher with triple-drug therapy than dual-drug therapy, with statistically significant differences in role function, energy, and pain scores. Benefits of triple-drug therapy were largely confined to patients with CD4 cell counts of <or=50 cells/mm(3). Quality-adjusted survival time did not differ significantly between the 2 treatment groups. CONCLUSIONS: Triple-drug therapy with indinavir and 2 NRTIs resulted in a significant improvement in general health status after 24 weeks, especially in patients with low CD4 cell counts. Patients receiving triple-drug therapy also had significantly better role function, energy, and pain scores than did patients treated with dual-drug therapy.

Adult↗
PubMed2006

The KLEAN study of fosamprenavir-ritonavir versus lopinavir-ritonavir, each in combination with abacavir-lamivudine, for initial treatment of HIV infection over 48 weeks: a randomised non-inferiority trial.

BACKGROUND: Lopinavir-ritonavir is a preferred protease inhibitor co-formulation for initial HIV-1 treatment. Fosamprenavir-ritonavir has shown similar efficacy and safety to lopinavir-ritonavir when each is combined with two nucleoside reverse transcriptase inhibitors. We compared the two treatments directly in antiretroviral-naive patients. METHODS: This open-label, non-inferiority study included 878 antiretroviral-naive, HIV-1-infected patients randomised to receive either fosamprenavir-ritonavir 700 mg/100 mg twice daily or lopinavir-ritonavir 400 mg/100 mg twice daily, each with the co-formulation of abacavir-lamivudine 600 mg/300 mg once daily. Primary endpoints were proportion of patients achieving HIV-1 RNA less than 400 copies per mL at week 48 and treatment discontinuations because of an adverse event. The intent-to-treat analysis included all patients exposed to at least one dose of randomised study medication. This study is registered with ClinicalTrials.gov, number NCT00085943. FINDINGS: At week 48, non-inferiority of fosamprenavir-ritonavir to lopinavir-ritonavir (95% CI around the treatment difference -4.84 to 7.05) was shown, with 315 of 434 (73%) patients in the fosamprenavir-ritonavir group and 317 of 444 (71%) in the lopinavir-ritonavir group achieving HIV-1 RNA less than 400 copies per mL. Treatment discontinuations due to an adverse event were few and occurred with similar frequency in the two treatment groups (fosamprenavir-ritonavir 53, 12%; lopinavir-ritonavir 43, 10%). Diarrhoea, nausea, and abacavir hypersensitivity were the most frequent drug-related grade 2-4 adverse events. Treatment-emergent drug resistance was rare; no patient had virus that developed reduced susceptibility to fosamprenavir-ritonavir or lopinavir-ritonavir. INTERPRETATION: Fosamprenavir-ritonavir twice daily in treatment-naive patients provides similar antiviral efficacy, safety, tolerability, and emergence of resistance as lopinavir-ritonavir, each in combination with abacavir-lamivudine.

Carbamates↗
PubMed2001

Simplification with abacavir-based triple nucleoside therapy versus continued protease inhibitor-based highly active antiretroviral therapy in HIV-1-infected patients with undetectable plasma HIV-1 RNA.

OBJECTIVE: To assess the antiviral efficacy, safety and adherence in patients switched to an abacavir-containing nucleoside reverse transcriptase inhibitor (NRTI) regimen after long-term HIV-1 RNA suppression with a dual NRTI/protease inhibitor (PI) combination. METHODS: In an open-label, multicentre study, patients receiving 2NRTI plus PI for at least 6 months, with a history of undetectable plasma HIV-1 RNA since the initiation of therapy and plasma HIV-1 RNA < 50 copies/ml at screening, were randomly assigned to replace the PI with abacavir (n = 105) or continue the same treatment (n = 106). Clinical assessments included plasma HIV-1 RNA, chemistry, haematology, lymphocyte counts, and adverse event reports. Adherence to treatment was assessed by patient self-report. RESULTS: A significantly longer time to treatment failure was demonstrated in the abacavir arm compared with the PI arm (P = 0.03) while treatment failure was experienced by significantly more patients in the PI arm: 24 (23%) versus 12 (12%) (P = 0.03). Therapy-limiting toxicity led to treatment failure in eight versus 14 cases in the abacavir and PI arms, respectively, whereas virological rebound was the cause in four versus two cases. Significant reductions in cholesterol and non-fasting triglyceride plasma levels at 48 weeks were observed in the abacavir arm (P < 0.001 andP = 0.035, respectively). The number of patients reporting no difficulty in taking their therapy showed a marked increase from baseline in the abacavir arm. CONCLUSION: The replacement of PI by abacavir in a triple combination regimen following prolonged suppression of plasma HIV-1 RNA provides continued virological suppression, significant improvements in lipid abnormalities and enhanced ease of dosing.

Adult↗
PubMed2004

Similar adherence rates favor different virologic outcomes for patients treated with nonnucleoside analogues or protease inhibitors.

BACKGROUND: This prospective study verified the effect of adherence on the risk of virologic failure. METHODS: At enrollment in the study, a total of 543 patients who were following a steady (duration, >or=6 months) and effective (viral load, <50 human immunodeficiency virus [HIV] RNA copies/mL) regimen of highly active antiretroviral therapy (HAART) completed a self-reported questionnaire derived from the Adult AIDS Clinical Trials Group Adherence Follow-up Questionnaire. Patients were followed up for the subsequent 6 months to document virologic failure, which was defined as 2 consecutive viral load measurements of >500 HIV RNA copies/mL. RESULTS: Only the type of treatment and the adherence rate at baseline were significantly associated with the virologic end point. Among patients who reported an adherence rate of 95%. When analysis was adjusted according to the type of regimen received, patients who were receiving protease inhibitor (PI)-based HAART and who had an adherence rate of up to 85% had a virologic failure rate of >20%, whereas, only for patients who were receiving nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based HAART and who had an adherence rate of 10%. For the comparison of NNRTI-treated patients and PI-treated patients with an adherence rate of 75%-95%, the odds ratio was 0.157 (95% confidence interval, 0.029-0.852). The number of pills and daily doses received correlated with the reported adherence rate. CONCLUSIONS: Patients receiving NNRTIs report a higher rate of adherence than do patients receiving PIs. Adherence is significantly influenced by the number of pills and daily doses received. Low adherence is a major determinant of virologic failure; however, different therapies have different cutoff values for adherence that determine a significant increment of risk.

Adult↗
PubMed1999

Efavirenz, nelfinavir, and stavudine rescue combination therapy in HIV-1-positive patients heavily pretreated with nucleoside analogues and protease inhibitors.

Tolerability, activity, and pharmacokinetic parameters of a combination therapy with efavirenz (EFV), nelfinavir (NFV), and stavudine (d4T) were evaluated in this study. Forty-seven HIV-1-infected study subjects, naive to NFV and nonnucleoside reverse transcriptase inhibitors (NNRTIs), who had experienced virologic failure while being treated with combination antiretroviral therapies including protease inhibitors (PIs), were enrolled. At baseline, HIV-1 viral load in plasma was 4.8 log10, CD4+ count was 204 cells/microl (both mean values); patients had received a mean of 3.1 different treatments (range, 2-5 treatments). Study medications were generally well tolerated; 7 of 47 patients (14.8%) were dropped from the study because of related drug toxicity. At week 24, mean plasma viral load (pVL) was reduced by 1.9 log10, with mean CD4+ count increased to 324 cells/microl (+/-59% from baseline); pVL was below the limit of detection (500 copies/ml) in 46.1% of patients. An extended follow-up study was performed at 12 months. Results showed a reduction of 1.7 log10 in pVL from basal values that was consistent with values observed at months 3 and 6. A history of previous use of PIs represented a negative prognostic marker. Sequencing analysis, performed in a subset of patients, showed the presence of multiple point mutations associated with PI resistance. Pharmacokinetic analysis demonstrated a marked interindividual variability in NFV plasma concentrations, producing in 4 of 18 patients (22%) trough concentrations lower than minimum effective concentration. In pretreated patients, further studies are needed to characterize the pharmacokinetic factors that affect response to therapy and the association of these results with the 95% inhibitory concentration (IC95) determined by phenotyping.

Adult↗
PubMed1995

Antiviral therapy for human immunodeficiency virus infections.

Depending on the stage of their intervention with the viral replicative cycle, human immunodeficiency virus inhibitors could be divided into the following groups: (i) adsorption inhibitors (i.e., CD4 constructs, polysulfates, polysulfonates, polycarboxylates, and polyoxometalates), (ii) fusion inhibitors (i.e., plant lectins, succinylated or aconitylated albumins, and betulinic acid derivatives), (iii) uncoating inhibitors (i.e., bicyclams), (iv) reverse transcription inhibitors acting either competitively with the substrate binding site (i.e., dideoxynucleoside analogs and acyclic nucleoside phosphonates) or allosterically with a nonsubstrate binding site (i.e., non-nucleoside reverse transcriptase inhibitors), (v) integration inhibitors, (vi) DNA replication inhibitors, (vii) transcription inhibitors (i.e., antisense oligodeoxynucleotides and Tat antagonists), (viii) translation inhibitors (i.e., antisense oligodeoxynucleotides and ribozymes), (ix) maturation inhibitors (i.e., protease inhibitors, myristoylation inhibitors, and glycosylation inhibitors), and finally, (x) budding (assembly/release) inhibitors. Current knowledge, including the therapeutic potential, of these various inhibitors is discussed. In view of their potential clinical the utility, the problem of virus-drug resistance and possible strategies to circumvent this problem are also addressed.

Antiviral Agents↗
PubMed2003

Perspectives on HAART: switch maintenance therapy.

Switch studies have been carried out to explore changes in side effects in adherence. Discontinuing the protease inhibitor (PI) component of highly active antiretroviral therapy (HAART) regimen is often associated with improved adherence and improved quality of life. Following switching from a PI to a non-nucleoside reverse transcriptase inhibitor or abacavir, there is however a clear trend toward an improved metabolic profile particularly in insulin resistance and triglyceride levels when patients discontinue their PI. Peripheral wasting is likely to be associated with nucleoside analogues and for individuals with isolated fat accumulation, modification of HAART is not recommended. Virological suppression can be maintained following switch if adequate suppression of the virus has been achieved for at least six months prior to switch and the patient has not been previously exposed to suboptimal HAART. Discontinuing the PI preserves this class of agents for future use. Switching however may be associated with other side effects; hypersensitivity, skin rashes, hepatic or neuropsychiatric events.

Alkynes↗
PubMed1999

Regression of AIDS-related Kaposi's sarcoma following antiretroviral therapy with protease inhibitors: biological correlates of clinical outcome.

The clinical response of AIDS-related Kaposi's sarcoma (KS) to highly active antiretroviral therapy (HAART), a combination of human immunodeficiency virus type 1 (HIV-1) protease and reverse transcriptase inhibitors, was studied in 11 patients, all but one with progressive KS. CD4+ cell counts, plasma HIV-1 RNA levels, and antibody titres to lytic ORF65 and latency-associated human herpes virus type 8 (HHV-8) proteins were determined in sequential samples. Six complete and three partial clinical responses were achieved in a median time of 6 and 3 months, respectively, and confirmed after a median time of 16 months on HAART. 2 patients showed disease progression. A consistent decrease in HIV-1 RNA levels, paralleled by an increase in CD4+ cell counts, was observed in all patients who showed complete or partial clinical response; HIV-1 RNA levels remained persistently high in the two patients who progressed, despite a change in HAART. HHV-8 antibody titres were generally higher in patients with mucosal/visceral involvement compared with patients with limited disease; a decrease in ORF65 antibody titre was significantly associated with a clinical response. These results indicate that HAART is effective for AIDS-related KS; the clinical response correlates with a decrease in plasma HIV-1 RNA levels, an increase in CD4+ lymphocytes, and a decrease in antibodies to ORF65 HHV-8 protein.

Adult↗
PubMed1996

In vitro antiviral activity of 141W94 (VX-478) in combination with other antiretroviral agents.

141W94 (VX-478) is a novel HIV-1 protease inhibitor with an IC50 of 0.08 microM against HIV-1 (strain IIIB) and a mean IC50 of 0.012 microM against six HIV clinical isolates. 141W94 was synergistic on the basis of isobologram analysis with each of the following reverse transcriptase inhibitors: AZT, 935U83, 524W91, 1592U89 and ddl, 141W94 was also synergistic with saquinavir and additive with either indinavir or ritonavir. Resistance to 141W94 has been reported in vitro passage experiments. The binding of 141W94 to human alpha 1-acid glycoprotein was relatively weak (Kd = 4 microM) and the off-rate for the drug is very fast (> or = 100 s-1). Only a 2-fold reduction of in vitro antiviral activity was observed in the presence of 45% human plasma. No serious drug associated adverse experiences were reported in a Phase I placebo-controlled, single-dose escalation, pharmacokinetic and safety study. The average concentration of 141W94 at 8 and 12 h after single doses of 900 and 1200 mg, respectively, was in excess of 10 times the IC50. As 141W94 is synergistic with a variety of anti-HIV-1 agents and exhibits a unique cross resistance profile compared to other protease inhibitors, 141W94 is considered a good candidate for combination therapy.

Carbamates↗