ritonavir and amprenavir

Molecular mechanisms behind the defects in insulin production and secretion associated with antihuman immunodeficiency virus (anti-HIV) therapy and the development of HIV-associated lipodystrophy syndrome (HALS) are discussed in this article. Data suggesting insulin resistance on the beta cell and defects in first-phase insulin release of HALS patients are presented. Hepatic extraction of insulin, nonglucose insulin secretagogues and insulin-like growth factor release may exert influence on the demand of circulating insulin and on insulin secretion in HIV-infected patients. Finally, the paucity in understanding the incretin effects in HIV and HIV therapy in relation to insulin secretion is highlighted.

Topics: Carbamates; Furans; HIV Protease Inhibitors; HIV-Associated Lipodystrophy Syndrome; Humans; Indinavir; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Nelfinavir; Ritonavir; Sulfonamides

Darunavir is the result of wide and in-depth investigation into HIV protease inhibitors (PIs). This drug is a nonpeptide PI, with a distinct chemical structure that, by conferring it drug with enhanced binding affinity and a slower dissociation rate, makes it more potent than the remaining PIs developed to date. Because of its pharmacokinetic characteristics, darunavir must be coadministered with low doses of ritonavir. Furthermore, these characteristics allow oral administration (preferably with meals), once-daily administration in non-resistant HIV strains, and a less complicated treatment regimen with improved convenience in highly varied contexts, including mild-to-moderate renal and hepatic impairment. The potential of darunavir for pharmacological interactions is highly acceptable and this drug can be administered without dose adjustments with almost all antiretroviral agents except maraviroc, lopinavir, saquinavir and tipranavir. There are no problems of pharmacodynamic antagonism with any of these drugs. Cytotoxic doses are well above therapeutic doses, providing a wide safety margin. The spectrum of action is very wide, and darunavir is effective against all subtypes of HIV-1 and against HIV-2 and acts well in mononuclear and monocyte/macrophage cell lines. Darunavir is also active against most HIV strains resistant to the remaining PIs and the robustness of this drug against the known mechanisms of resistance of HIV is also superior to that of the other available PIs. Consequently, the induction and selection of mutations conferring resistance to this drug may be slower and more difficult, resulting in its antiviral effect remaining unchanged for prolonged periods.

Topics: Administration, Oral; Carbamates; Clinical Trials as Topic; Cytochrome P-450 CYP3A; Darunavir; Drug Interactions; Drug Resistance, Viral; Drug Therapy, Combination; Female; Furans; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Male; Molecular Structure; Ritonavir; Sulfonamides

Protease inhibitors (PIs) are potent competitive inhibitors of the human immunodeficiency virus (HIV) widely used in the treatment of the acquired immune deficiency syndrome (AIDS) and prescribed in combination with other antiretroviral drugs. So far ten PIs were approved by the United States Food and Drug Administration (FDA) for the treatment of HIV infection. In this mini review, quality control methods of each PI are discussed on the basis of analytical techniques published in the literature. Special attention is given to summarize the LC methods described for the analysis of the selected PIs in both drug substances and products with the available literature till date.

Topics: Anti-HIV Agents; Atazanavir Sulfate; Carbamates; Chromatography, Liquid; Darunavir; Drug Contamination; Furans; HIV Protease Inhibitors; Indinavir; Lopinavir; Nelfinavir; Oligopeptides; Organophosphates; Pyridines; Pyrimidinones; Pyrones; Quality Control; Ritonavir; Saquinavir; Sulfonamides

Amprenavir is an HIV-1 protease inhibitor, the first in vitro activity studies of which were published in 1995. During in vivo development, it became clear that the pharmacokinetics of the drug would result in patients taking a large number of pills daily. The first comparative studies of amprenavir versus other protease inhibitors showed it had comparatively weak activity. Thus, studies using low doses of ritonavir to enhance the pharmacokinetic profile of amprenavir were first communicated in 2000. Only a small number of clinical trials in HIV-1-infected patients have been published. The pharmacokinetics of amprenavir have been documented in both healthy individuals and in HIV-1-infected patients. Amprenavir trough plasma concentrations increase 3- to 10-fold and the area under the concentration-time curve (AUC) increases 2- to 3-fold when using amprenavir 450 or 600 mg combined with ritonavir 100mg twice daily. Peak concentrations of amprenavir are less influenced by ritonavir coadministration, with a 1- to 2-fold increase. As there is no pharmacokinetic advantage to increasing ritonavir doses, the combination has only been used with low doses of ritonavir (100mg twice daily or 200 mg once or twice daily). Concomitant use of currently available non-nucleoside reverse transcriptase inhibitors (NNRTIs)--efavirenz or nevirapine--is possible when amprenavir is coadministered with ritonavir, despite the pharmacokinetic interactions described when they are used with amprenavir alone. Fosamprenavir (GW 433908) is a prodrug of amprenavir primarily metabolised to amprenavir in the epithelial cells of the intestine. At steady state, plasma trough concentrations and AUC are slightly greater with fosamprenavir (two pills of 700 mg twice daily) than amprenavir (eight soft gel capsules of 150 mg twice daily). The clinical adverse effects of amprenavir are similar whether administered unboosted or in combination with ritonavir. Skin rashes do not appear to be more frequent. With regard to lipid profiles, the addition of ritonavir to amprenavir induces an increase in cholesterol and triglyceride levels; however, prospective comparative studies are lacking. In short-term prospective trials in antiretroviral-naive individuals, virological suppression with highly active antiretroviral therapy containing amprenavir plus ritonavir is similar to or higher than with unboosted amprenavir, with a smaller pill intake. Few comparative data are available in treatment-experienced

Topics: Anti-HIV Agents; Carbamates; Drug Resistance; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Organophosphates; Ritonavir; Sulfonamides

There are currently (July, 2002) six protease inhibitors approved for the treatment of HIV infection, each of which can be classified as peptidomimetic in structure. These agents, when used in combination with other antiretroviral agents, produce a sustained decrease in viral load, often to levels below the limits of quantifiable detection, and a significant reconstitution of the immune system. Therapeutic regimens containing one or more HIV protease inhibitors thus provide a highly effective method for disease management. The important role of protease inhibitors in HIV therapy, combined with numerous challenges remaining in HIV treatment, have resulted in a continued effort both to optimize regimens using the existing agents and to identify new protease inhibitors that may provide unique properties. This review will provide an overview of the discovery and clinical trials of the currently approved HIV protease inhibitors, followed by an examination of important aspects of therapy, such as pharmacokinetic enhancement, resistance and side effects. A description of new peptidomimetic compounds currently being investigated in the clinic and in preclinical discovery will follow.

Topics: Anti-HIV Agents; Atazanavir Sulfate; Carbamates; Clinical Trials as Topic; Dipeptides; Furans; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Models, Molecular; Molecular Mimicry; Molecular Structure; Nelfinavir; Oligopeptides; Organophosphates; Peptides; Phenylbutyrates; Pyridines; Pyrimidinones; Ritonavir; Saquinavir; Sulfonamides; Urethane

Topics: Carbamates; Drug Resistance, Microbial; Furans; HIV; HIV Infections; HIV Protease; HIV Protease Inhibitors; Humans; Indinavir; Mutation; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides

The dimeric aspartyl protease of HIV has been the subject of intense research for almost a decade. Knowledge of the substrate specificity and catalytic mechanism of this enzyme initially guided the development of several potent peptidomimetic small molecule inhibitors. More recently, the solution of the HIV protease structure led to the structure-based design of improved peptidomimetic and non-peptidomimetic antiviral compounds. Despite the qualified success of these inhibitors, the high mutation rate associated with RNA viruses continues to hamper the long-term clinical efficacy of HIV protease inhibitors. The dimeric nature of the viral protease has been conducive to the investigation of dominant-negative inhibitors of the enzyme. Some of these inhibitors are defective protease monomers that interact with functional monomers to form inactive protease heterodimers. An advantage of macromolecular inhibitors as compared to small-molecule inhibitors is the increased surface area of interaction between the inhibitor and the target gene product. Point mutations that preserve enzyme activity but confer resistance to small-molecule inhibitors are less likely to have an adverse effect on macromolecular interactions. The use of efficient retrovirus vectors has facilitated the delivery of these macromolecular inhibitors to primary human lymphocytes. The vector-transduced cells were less susceptible to HIV infection in vitro, and showed similar levels of protection compared to other macromolecular inhibitors of HIV replication, such as RevM10. These preliminary results encourage the further development of dominant-negative HIV protease inhibitors as a gene therapy-based antiviral strategy.

Topics: Amino Acid Sequence; Carbamates; Furans; Genetic Therapy; Genetic Vectors; HIV Protease; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Lentivirus; Models, Molecular; Molecular Structure; Nelfinavir; Retroviridae; Ritonavir; Saquinavir; Sulfonamides; Transfection

This review deals with clinical applications of compounds that inhibit the action of the protease encoded within the genome of human immunodeficiency virus (HIV). The HIV-protease is essential for viral maturation and represents an important therapeutic target in the fight against AIDS. Following a brief overview of the enzyme structure and function, the article focuses on a number of peptide and non-peptide based HIV-protease inhibitors that are in current clinical use. These drugs are discussed both with respect to their efficacy in treatment of AIDS, and to problems related to insurgence of viral resistance and side effects seen to date in patient populations.

Topics: Acquired Immunodeficiency Syndrome; Anti-HIV Agents; Binding Sites; Carbamates; Clinical Trials as Topic; Computer-Aided Design; Crystallography, X-Ray; Drug Design; Drug Resistance, Microbial; Drug Therapy, Combination; Furans; HIV Protease; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Nelfinavir; Oligopeptides; Pyridines; Pyrones; Randomized Controlled Trials as Topic; Ritonavir; Saquinavir; Sulfonamides

The development of antiretrovirals has led to a revolution in the care of patients infected with HIV. What was once a uniformly fatal syndrome has become a more treatable, chronic, infectious disease. Central to this revolution have been the protease inhibitors, a class of drugs with potent antiretroviral activity. The first member of this class was approved for use in 1995 and there are now five protease inhibitors approved by the US Food and Drug Administration (FDA): amprenavir, indinavir, nelfinavir, ritonavir and saquinavir. As a result of the magnitude of the HIV pandemic coupled with the clinically proven efficacy of protease inhibitors, there are currently hundreds of ongoing clinical trials with these agents. Trial designs include comparisons between the various licensed protease inhibitors, comparisons of protease inhibitors to other classes of potent antiretroviral drugs, investigations with new protease inhibitors, investigations of protease inhibitor-related toxicities and attempts at simplifying current dosing regimens.

Topics: Carbamates; Clinical Trials as Topic; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides; United States; United States Food and Drug Administration

Topics: Carbamates; CD4 Lymphocyte Count; Female; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Male; Nelfinavir; Ritonavir; Saquinavir; Semen; Sulfonamides; Viral Load

Deaths related to the human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome and the incidence of opportunistic infections have been drastically decreased in the industrialized world. These reductions are mainly due to recent advances in the management of HIV infection, including the availability of new therapies. Until November 1995, the antiretroviral drugs available and approved by the Food and Drug Administration for clinical use in the United States consisted of only four nucleoside analogue reverse transcriptase inhibitors: zidovudine, zalcitabine, didanosine, and stavudine. Since then, 2 new classes of agents and 10 new agents have been approved; thus, the number of available antiretroviral drugs has more than tripled. Additional drugs and newer classes of antiretrovirals are in various stages of development. Because of the availability of more drugs, the complexity of HIV treatment has increased. Selecting an appropriate antiretroviral therapeutic regimen involves addressing multiple interdependent issues, including patient adherence, pharmacokinetic properties of the drugs (including food effects and drug-drug interactions), drug resistance, and overlapping adverse effects.

Topics: Adolescent; Adult; Alkynes; Anti-HIV Agents; Benzoxazines; Carbamates; Cyclopropanes; Delavirdine; Didanosine; Dideoxynucleosides; Female; Furans; HIV Infections; Humans; Indinavir; Lamivudine; Nelfinavir; Nevirapine; Oxazines; Pregnancy; Pregnancy Complications, Infectious; Protease Inhibitors; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Stavudine; Sulfonamides; Zalcitabine; Zidovudine

Topics: Carbamates; Drug Resistance; Furans; HIV Protease; HIV Protease Inhibitors; Indinavir; Nelfinavir; Pyridines; Pyrones; Ritonavir; Saquinavir; Structure-Activity Relationship; Sulfonamides

Dolutegravir (DTG) is an HIV integrase inhibitor (INI) with demonstrated activity in INI-naive and INI-resistant patients. The objective of this open-label, 2-period, single-sequence study was to evaluate the effect of fosamprenavir-ritonavir (FPV-RTV) on the steady-state plasma pharmacokinetics of DTG. Twelve healthy subjects received 50 mg DTG once daily for 5 days (period 1), followed by 10 days of 50 mg DTG once daily in combination with 700/100 mg FPV-RTV every 12 h (period 2). All doses were administered in the fasting state. Serial pharmacokinetic samples for DTG and amprenavir and safety assessments were obtained throughout the study. Noncompartmental pharmacokinetic analysis was performed, and geometric least-squares mean ratios and 90% confidence intervals were generated for within-subject treatment comparison. Fosamprenavir-ritonavir decreased the DTG area under the concentration-time curve, maximum concentration in plasma, and concentration in plasma at the end of the dosing interval by 35%, 24%, and 49%, respectively. Both DTG and DTG with FPV-RTV were well tolerated; no subject withdrew because of adverse events. The most frequently reported drug-related adverse events were rash, abnormal dreams, and nasopharyngitis. The modest decrease in DTG exposure when it was coadministered with FPV-RTV is not considered clinically significant, and DTG dose adjustment is not required with coadministration of FPV-RTV in INI-naive patient populations on the basis of established "no-effect" boundaries of DTG. In the INI-resistant population, as a cautionary measure, alternative combinations that do not include FPV-RTV should be considered. (This study has been registered at ClinicalTrials.gov under identifier NCT01209065.).

Topics: Adult; Area Under Curve; Carbamates; Drug Administration Schedule; Drug Interactions; Female; Furans; Healthy Volunteers; Heterocyclic Compounds, 3-Ring; HIV Integrase; HIV Integrase Inhibitors; HIV Protease Inhibitors; Humans; Male; Organophosphates; Oxazines; Piperazines; Pyridones; Ritonavir; Sulfonamides

Fosamprenavir (FPV) is the phosphate ester prodrug of the HIV-1 protease inhibitor amprenavir (APV). A pediatric population pharmacokinetic model for APV was developed and simulation was used to identify dosing regimens for pediatric patients receiving FPV in combination with ritonavir (RTV) which resulted in concentrations similar to those in adults receiving FPV/RTV 700/100 mg BID. Pharmacokinetic data was obtained from HIV infected subjects aged 2 months to 18 years receiving either FPV or FPV/RTV. A two-compartment model with first order absorption and elimination was an appropriate structural model. Significant covariates in the model included RTV coadministration on clearance, fed status on bioavailability for the oral suspension, body weight on clearance and volume terms, black race on clearance, and age on clearance. The following FPV/RTV twice daily dosing regimens in pediatric patients delivered plasma APV exposure similar to adults: 45/7 mg/kg in patients weighing <11 kg, 30/3 mg/kg in patients weighing 11 to <15 kg, 23/3 mg/kg in patients weighing 15 to <20 kg, and 18/3 mg/kg in patients weighting ≥20 kg. Additionally children weighing ≥39 kg can receive the adult regimen.

Topics: Adolescent; Carbamates; Child; Child, Preschool; Computer Simulation; Drug Dosage Calculations; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Infant; Male; Models, Biological; Organophosphates; Prodrugs; Ritonavir; Sulfonamides

The ANRS EP45 "Aging" study investigates the cellular mechanisms involved in the accelerated aging of HIV-1 infected and treated patients. The present report focuses on lamin A processing, a pathway known to be altered in systemic genetic progeroid syndromes.. 35 HIV-1 infected patients being treated with first line antiretroviral therapy (ART, mean duration at inclusion: 2.7±1.3 years) containing boosted protease inhibitors (PI/r) (comprising lopinavir/ritonavir in 65% of patients) were recruited together with 49 seronegative age- and sex-matched control subjects (http://clinicaltrials.gov/, NCT01038999). In more than 88% of patients, the viral load was <40 copies/ml and the CD4+ cell count was >500/mm³. Prelamin A processing in peripheral blood mononuclear cells (PBMCs) from patients and controls was analysed by western blotting at inclusion. PBMCs from patients were also investigated at 12 and 24 months after enrolment in the study. PBMCs from healthy controls were also incubated with boosted lopinavir in culture medium containing various concentrations of proteins (4 to 80 g/L).. Lamin A precursor was not observed in cohort patient PBMC regardless of the PI/r used, the dose and the plasma concentration. Prelamin A was detected in PBMC incubated in culture medium containing a low protein concentration (4 g/L) but not in plasma (60-80 g/L) or in medium supplemented with BSA (40 g/L), both of which contain a high protein concentration.. Prelamin A processing abnormalities were not observed in PBMCs from patients under the PI/r first line regimen. Therefore, PI/r do not appear to contribute to lamin A-related aging in PBMCs. In cultured PBMCs from healthy donors, prelamin A processing abnormalities were only observed when the protein concentration in the culture medium was low, thus increasing the amount of PI available to enter cells. ClinicalTrials.gov NCT01038999 http://clinicaltrials.gov/ct2/show/NCT01038999.

Topics: Aging; Atazanavir Sulfate; Carbamates; Cross-Sectional Studies; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lamin Type A; Leukocytes, Mononuclear; Longitudinal Studies; Lopinavir; Male; Nuclear Proteins; Oligopeptides; Protein Precursors; Pyridines; Ritonavir; Sulfonamides; Viral Load

Objective An open-label, three-period pharmacokinetic study was conducted to investigate the drug interaction potential between fosamprenavir (FPV) and tenofovir disoproxil fumarate (TDF). Methods Thirty-six healthy subjects received TDF 300 mg once daily (qd) for 7 days (period 1), and then were randomized to 14 days of either FPV 1400 mg twice daily (bid) or FPV/ritonavir (RTV) 700/100 mg bid alone or with TDF (period 2). Subjects continued their randomized dose of FPV for 14 more days, adding or removing TDF based upon its receipt in period 2 (period 3). Twenty-four-hour pharmacokinetic sampling was carried out on day 7 of period 1 and on day 14 of periods 2 and 3. Steady-state plasma amprenavir (APV) and tenofovir (TFV) pharmacokinetics were assessed by noncompartmental analysis and parameter values observed with each regimen were compared using geometric mean ratios with 90% confidence intervals. Results After TDF coadministration, APV geometric mean minimum concentration (C(min)), maximum concentration (C(max)), and area under the plasma concentration-time curve (AUC) increased by 31, 3 and 7% above values observed with unboosted FPV alone; they also increased by 31, 4 and 16% above values observed with FPV/RTV alone. TFV C(min), C(max) and AUC decreased by 12, 25 and 15% after FPV coadministration and by 9, 18 and 7% after FPV/RTV coadministration. No significant changes in RTV pharmacokinetics were observed. No differences were noted in adverse events among dosing periods. Conclusions In this evaluation of the interaction between FPV and TDF, increases in APV exposures and modest decreases in TFV exposures were observed. These were unlikely to be clinically significant.

Topics: Adenine; Adolescent; Adult; Aged; Anti-HIV Agents; Carbamates; Cross-Over Studies; Drug Administration Schedule; Drug Eruptions; Drug Interactions; Drug Therapy, Combination; Female; Furans; HIV Infections; Humans; Male; Middle Aged; Organophosphates; Organophosphonates; Prodrugs; Ritonavir; Sulfonamides; Tenofovir; Young Adult

To quantify the pharmacokinetics of amprenavir and atazanavir (administered as the prodrug fosamprenavir) alone and in combination in human immunodeficiency virus (HIV)-negative subjects.. Randomized, open-label, three-way crossover study.. Research facility.. Eleven men and 10 women who were seronegative for HIV.. Subjects were randomized to 14-day treatment periods of fosamprenavir 1400 mg once/day, atazanavir 400 mg once/day, or fosamprenavir 1400 mg plus atazanavir 400 mg once/day; after a washout period of at least 21 days between each treatment, they received the other two treatments.. Subjects underwent 24-hour pharmacokinetic sampling at baseline and on day 14 of each treatment period. Primary outcome measures were area under the plasma concentration-time curve (AUC) and maximum concentration (C(max)) for amprenavir and atazanavir. Atazanavir significantly enhanced the exposure of amprenavir. When fosamprenavir was given alone, the geometric mean of amprenavir's AUC was 20.2 microg x hour/ml (95% confidence interval [CI] 19.1-21.2 microg x hr/ml). When given in combination with atazanavir, amprenavir had an AUC of 39.8 microg x hour/ml (95% CI 38.7-40.9 microg x hr/ml). Similarly, the C(max) for amprenavir increased from 4193 ng/ml (95% CI 3927-4459 ng/ml) to 6621 ng/ml (95% CI 6427-6814 ng/ml) when given in combination with atazanavir. In contrast, AUC and C(max) for atazanavir significantly decreased when atazanavir was coadministered with fosamprenavir; AUC decreased from 17.6 microg x hour/ml (95% CI 16.6-18.7 microg x hr/ml) to 11.8 microg x hour/ml (95% CI 11.3-12.3 microg x hr/ml), and C(max) decreased from 2507 ng/ml (95% CI 2379-2635 ng/ml) to 1832 ng/ml (95% CI 1752-1911 ng/ml). Adverse events were assessed at each study visit and 1 month after the subjects completed the three treatments. Both drugs were well tolerated. One serious adverse event (grade 3 acute pancreatitis) occurred and resolved without further incident.. Atazanavir 400 mg/day plus fosamprenavir 1400 mg/day significantly decreased concentrations of atazanavir compared with standard dosing regimens of each drug alone. This dosing scheme is not a recommended combination of dual, fully active protease inhibitors.

Topics: Adolescent; Adult; Aged; Atazanavir Sulfate; Carbamates; Drug Therapy, Combination; Female; Furans; HIV Protease Inhibitors; HIV Seronegativity; Humans; Male; Middle Aged; Oligopeptides; Organophosphates; Prodrugs; Pyridines; Ritonavir; Sulfonamides

The effects of different HIV protease inhibitors (PIs) on peripheral insulin resistance have been described, but less is known about their effects on insulin suppression of endogenous glucose production (EGP).. We tested the acute effects of 3 PIs, indinavir, ritonavir, and amprenavir, on EGP quantified by stable isotope techniques during the hyperinsulinemic, euglycemic clamp in 3 similar placebo-controlled protocols.. EGP was higher with indinavir in the hyperinsulinemic state than with placebo (4.1 +/- 1.3 vs. 2.2 +/- 0.8 microg x kg(-1) x min(-1), P = 0.04). A trend toward higher EGP was seen with ritonavir (3.6 +/- 0.3 vs. 3.0 +/- 0.5 microg x kg(-1) x min(-1), P = 0.08). There was no evidence that amprenavir blunted insulin suppression of EGP compared with placebo (2.9 +/- 0.04 vs. 3.2 +/- 0.7 microg x kg(-1) x min(-1), P = 0.63).. Some PIs can acutely blunt the ability of insulin to suppress EGP, but, as with insulin resistance, the effects of PIs on EGP are drug-specific, not class-specific.

Topics: Carbamates; Furans; Glucose; HIV Protease Inhibitors; Human Experimentation; Humans; Indinavir; Insulin; Male; Placebos; Ritonavir; Sulfonamides

To compare steady-state pharmacokinetics and pharmacodynamics of methadone enantiomers when coadministered with fosamprenavir 700 mg-ritonavir 100 mg twice/day.. Open-label, single-sequence, two-period crossover, drug-interaction study.. Two university-affiliated research centers.. Twenty-six opioid-dependent, methadone-maintained, healthy adults.. Subjects received their usual daily dose of methadone alone for 4 days (period 1). Subjects then received the same daily dose of methadone plus fosamprenavir 700 mg-ritonavir 100 mg twice/day for 14 days (period 2).. Blood was collected on days 1-4 (period 1) and on days 11-14 (period 2) for plasma R- and S-methadone concentrations; amprenavir concentrations were assessed during period 2. Opioid-effect measures were assessed in each study period. Subjects served as their own controls for comparison of period 1 with period 2. Coadministration of fosamprenavir-ritonavir with methadone reduced plasma total R-methadone area under the plasma concentration-time curve over the dosing interval at steady state (AUC tau-ss) by 18%, maximum concentration at steady state (Cmax-ss) by 21%, and concentration at the end of the dosing interval at steady state (Ctau-ss) by 11%; time to reach Cmax-ss (Tmax) was delayed by 1.75 hours. Coadministration of fosamprenavir-ritonavir with methadone also reduced plasma total S-methadone AUC tau-ss and Cmax-ss by 43% each, Ctau-ss by 41%, and delayed Tmax by 0.85 hours. Fosamprenavir-ritonavir administered with methadone did not alter plasma amprenavir pharmacokinetics compared with historical control data; nor did it alter the unbound R-methadone at 2 and 6 hours after methadone dosing. Pharmacodynamic indexes remained essentially unchanged after adding fosamprenavir-ritonavir to methadone. No subject demonstrated opioid intoxication or withdrawal, or requested methadone dosage modification.. No adjustment in the dosages of either methadone or fosamprenavir 700 mg-ritonavir 100 mg twice/day is required during coadministration, on the basis of the small reduction in total R-methadone exposure, no change in unbound R-methadone, no clinically important opioid effects, and no change in amprenavir exposure.

Topics: Adult; Anti-HIV Agents; Carbamates; Cross-Over Studies; Drug Interactions; Female; Furans; Humans; Male; Methadone; Narcotics; Organophosphates; Prodrugs; Ritonavir; Stereoisomerism; Sulfonamides

The inhibitory quotient (IQ) of human immunodeficiency virus (HIV) protease inhibitors (PIs), which is the ratio of drug concentration to viral susceptibility, is considered to be predictive of the virological response. We used several approaches to calculate the IQs of amprenavir and lopinavir in a subset of heavily pretreated patients participating in the French National Agency for AIDS Research (ANRS) 104 trial and then compared their potentials for predicting changes in the plasma HIV RNA level. Thirty-seven patients were randomly assigned to receive either amprenavir (600 mg twice a day [BID]) or lopinavir (400 mg BID) plus ritonavir (100 or 200 mg BID) for 2 weeks before combining the two PIs. The 90% inhibitory concentration (IC(90)) was measured using a recombinant assay without or with additional human serum (IC(90+serum)). Total and unbound PI concentrations in plasma were measured. Univariate linear regression was used to estimate the relation between the change in viral load and the IC(90) or IQ values. The amprenavir phenotypic IQ values were very similar when measured with the standard and protein binding-adjusted IC(90)s. No relationship was found between the viral load decline and the lopinavir IQ. During combination therapy, the amprenavir and lopinavir genotypic IQ values were predictive of the viral response at week 6 (P = 0.03). The number of protease mutations (< 5 or > or = 5) was related to the virological response throughout the study. These findings suggest that the combined genotypic IQ and the number of protease mutations are the best predictors of virological response. High amprenavir and lopinavir concentrations in these patients might explain why plasma concentrations and the phenotypic IQ have poor predictive value.

Topics: Adult; Aged; Carbamates; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Female; France; Furans; Genotype; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Lopinavir; Male; Middle Aged; Phenotype; Prognosis; Pyrimidinones; Ritonavir; RNA, Viral; Sulfonamides; Treatment Outcome; Viral Load

Topics: Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Brazil; Carbamates; CD4 Lymphocyte Count; Drug Resistance, Viral; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Male; Pilot Projects; Prospective Studies; Pyrimidinones; Ritonavir; Saquinavir; Sulfonamides; Treatment Outcome

Once-daily (QD) fosamprenavir (FPV) at 1,400 mg boosted with low-dose ritonavir (RTV) at 200 mg is effective when it is used in combination regimens for the initial treatment of human immunodeficiency virus infection. Whether a lower RTV boosting dose (i.e., 100 mg QD) could ensure sufficient amprenavir (APV) concentrations with improved safety/tolerability is unknown. This randomized, two 14-day-period, crossover pharmacokinetic study compared the steady-state plasma APV concentrations, safety, and tolerability of FPV at 1,400 mg QD boosted with either 100 mg or 200 mg of RTV QD in 36 healthy volunteers. Geometric least-square (GLS) mean ratios and the associated 90% confidence intervals (CIs) were estimated for plasma APV maximum plasma concentrations (Cmax), the area under the plasma concentration-time curve over the dosing period (AUC0-tau), and trough concentrations (Ctau) during each dosing period. Equivalence between regimens (90% CIs of GLS mean ratios, 0.80 to 1.25) was observed for the plasma APV AUC0-tau (GLS mean ratio, 0.90 [90% CI, 0.84 to 0.96]) and Cmax (0.97 [90% CI, 0.91 to 1.04]). The APV Ctau was 38% lower with RTV at 100 mg QD than with RTV at 200 mg QD (GLS mean ratio, 0.62 [90% CI, 0.55 to 0.69]) but remained sixfold higher than the protein-corrected 50% inhibitory concentration for wild-type virus, with the lowest APV Ctau observed during the 100-mg QD period being nearly threefold higher. The GLS mean APV Ctau was 2.5 times higher than the historical Ctau for unboosted FPV at 1,400 mg twice daily. Fewer clinical adverse drug events and smaller increases in triglyceride levels were observed with the RTV 100-mg QD regimen. Clinical trials evaluating the efficacy and safety of FPV at 1,400 mg QD boosted by RTV at 100 mg QD are now under way with antiretroviral therapy-naïve patients.

Topics: Adolescent; Adult; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Carbamates; Female; Furans; HIV Infections; Humans; Male; Middle Aged; Organophosphates; Prodrugs; Ritonavir; Sulfonamides

We report the results of the extended follow-up at one year of a randomized trial evaluating the virological efficacy of a salvage therapy combining lopinavir and amprenavir with either 200 or 400 mg/day ritonavir, along with optimized nucleoside reverse transcriptase inhibitors, in patients carrying multidrug-resistant isolates. The combination of amprenavir, lopinavir and ritonavir (400 mg/day) is durably potent, yielding a sustained virological response (HIV RNA < 50 copies) in 39% of cases.

Topics: Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Carbamates; Drug Resistance, Multiple, Viral; Follow-Up Studies; Furans; HIV Infections; HIV-1; Humans; Lopinavir; Pyrimidinones; Ritonavir; Salvage Therapy; Sulfonamides

Plasma ketoconazole (KETO), amprenavir (APV), and ritonavir (RTV) pharmacokinetics were evaluated in 15 healthy subjects after being treated with KETO at 200 mg once daily (QD), fosamprenavir (FPV)/RTV at 700/100 mg twice daily (BID), and then KETO at 200 mg QD plus FPV/RTV at 700/100 mg BID in this open-label study. The KETO area under the concentration-time curve at steady state was increased 2.69-fold with FPV/RTV. APV exposure was unchanged, and RTV exposure was slightly increased.

Topics: Adolescent; Adult; Antifungal Agents; Area Under Curve; Carbamates; Drug Interactions; Drug Therapy, Combination; Female; Furans; HIV Protease Inhibitors; Humans; Ketoconazole; Male; Middle Aged; Organophosphates; Ritonavir; Sulfonamides; Treatment Outcome

The effect of tenofovir disoproxil fumarate (TDF) in combination with two boosted fosamprenavir regimens on amprenavir pharmacokinetic parameters was assessed in this prospective phase I crossover study with 30 healthy volunteers. The co-administration of TDF 300 mg once a day with fosamprenavir/ritonavir 1400/200 mg or 1400/100 mg once a day has no effect on the pharmacokinetics of amprenavir and results in non-significant increases of ritonavir pharmacokinetic parameters, suggesting that no dose modification is necessary when combining fosamprenavir/ritonavir with TDF.

Topics: Adenine; Anti-Retroviral Agents; Area Under Curve; Carbamates; Cross-Over Studies; Drug Administration Schedule; Drug Therapy, Combination; Furans; HIV Protease Inhibitors; HIV Seronegativity; Humans; Male; Organophosphates; Organophosphonates; Prospective Studies; Reverse Transcriptase Inhibitors; Ritonavir; Sulfonamides; Tenofovir

Amprenavir (APV), fosamprenavir (FPV), lopinavir (LPV), ritonavir (RTV) and efavirenz (EFV) are to varying degrees substrates, inducers and inhibitors of CYP3A4. Coadministration of these drugs might result in complex pharmacokinetic drug-drug interactions.. Two prospective, open-label, non-randomized studies evaluated APV and LPV steady-state pharmacokinetics in HIV-infected patients on APV 750 mg twice daily + LPV/RTV 533/133 mg twice daily with EFV (n=7) or without EFV (n=12) + background nucleosides (Study 1) and after switching FPV 1,400 mg twice daily for APV (n=10) (Study 2).. In Study 1 EFV and non-EFV groups did not differ in APV minimum plasma concentration (Cmin; 1.10 versus 1.06 microg/ml, P = 0.89), area under the concentration-time curve (AUC; 17.46 versus 24.34 microg x h/ml, P = 0.22) or maximum concentration (Cmax; 2.61 versus 4.33 microg/ml, P = 0.08); for LPV there was no difference in Cmin, (median: 3.66 versus 6.18 microg/ml, P = 0.20), AUC (81.84 versus 93.75 microg x h/ml, P = 0.37) or Cmax (10.36 versus 10.93 microg/ml, P = 0.61). In Study 2, after switching from APV to FPV, APV Cmin increased by 58% (0.83 versus 1.30 microg/ml, P = 0.0001), AUC by 76% (19.41 versus 34.24 micorg x h/ml, P = 0.0001), and Cmax by 75% (3.50 versus 6.14, P = 0.001). Compared with historical controls, LPV and RTV pharmacokinetics were not changed. All treatment regimens were well tolerated. Seven of eight completers (88%) maintained HIV-1 RNA <400 copies/ml 12 weeks after the switch (1 lost to follow up).. EFV did not appear to significantly alter APV and LPV pharmacokinetic parameters in HIV-infected patients taking APV 750 mg twice daily + LPV 533/133 mg twice daily. Switching FPV 1400 mg twice daily for APV 750 mg twice daily resulted in an increase in APV Cmin, AUC, and Cmax without changing LPV or RTV pharmacokinetics or overall tolerability.

Topics: Adult; Alkynes; Anti-HIV Agents; Benzoxazines; Carbamates; Cyclopropanes; Drug Interactions; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Male; Middle Aged; Organophosphates; Pyrimidinones; Ritonavir; Sulfonamides

Some HIV protease inhibitors (PIs) have been shown to induce insulin resistance in vitro but the degree to which specific PIs affect insulin sensitivity in humans is less well understood.. In two separate double-blind, randomized, cross-over studies, we assessed the effects of a single dose of ritonavir (800 mg) and amprenavir (1200 mg) on insulin sensitivity (euglycemic hyperglycemic clamp) in healthy normal volunteers.. Ritonavir decreased insulin sensitivity (-15%; P = 0.008 versus placebo) and non-oxidative glucose disposal (-30%; P = 0.0004), whereas neither were affected by amprenavir administration.. Compared to previously performed studies of identical design using single doses of indinavir and lopinavir/ritonavir, a hierarchy of insulin resistance was observed with the greatest effect seen with indinavir followed by ritonavir and lopinavir/ritonavir, with little effect of amprenavir.

Topics: Adult; Aged; Blood Glucose; Carbamates; Double-Blind Method; Energy Metabolism; Furans; Glucose Clamp Technique; HIV Protease Inhibitors; Humans; Indinavir; Insulin; Insulin Resistance; Lactic Acid; Lopinavir; Male; Middle Aged; Pyrimidinones; Ritonavir; Sulfonamides

To compare the effect of ritonavir on plasma amprenavir pharmacokinetics, healthy adults received either fosamprenavir (700 mg twice a day [BID]) or amprenavir (600 mg BID) alone and in combination with ritonavir (100 mg BID). Ritonavir increased plasma amprenavir pharmacokinetic parameters to a similar extent when coadministered with either fosamprenavir or amprenavir.

Topics: Adult; Area Under Curve; Carbamates; Cross-Over Studies; Drug Interactions; Drug Therapy, Combination; Female; Furans; HIV Protease Inhibitors; Humans; Male; Middle Aged; Organophosphates; Ritonavir; Sulfonamides

To evaluate fosamprenavir/lopinavir (LPV)/ritonavir (RTV), fosamprenavir/RTV, or LPV/RTV in antiretroviral treatment-experienced patients. Lack of drug interaction data prompted a pharmacokinetic substudy to minimize subject risk.. Multi-center, open-label, selectively randomized, steady-state pharmacokinetic study in HIV-infected subjects.. A planned independent interim review occurred after at least eight subjects were randomized to each arm. Subjects received twice daily LPV/RTV 400/100 mg (arm A; n = 8); fosamprenavir/RTV 700/100 mg (arm B; n = 8) or LPV/RTV/fosamprenavir 400/100/700 mg (arm C; n = 17). Plasma samples were collected over 12 h between study weeks 2 and 4. Pharmacokinetic parameters were compared based on a one-sided t-test on log-transformed data with a Peto stopping boundary (P < 0.001).. Amprenavir mean area under the curve over 12 h (AUC0-12 h) and concentration at 12 h (C12 h) (microg/ml) were, respectively, 42.7 microg x h/ml (range, 33.1-55.1) and 2.4 microg/ml (range, 1.4-3.2) in arm B and 17.4 microg x h/ml (range, 4.6-41.3) and 0.9 microg/ml (range, 0.2-2.7) in arm C: geometric mean ratio (GMR) arm C:B was 0.36 [99.9% upper confidence boundary (UCB), 0.64] and 0.31 (99.9% h UCB, 0.61), respectively (P < or = 0.0001). Lopinavir AUC0-12 h and C12 h were, respectively, 95.3 microg x h/ml (range, 60.3-119.3) and 6.3 microg/ml (range, 2.2-9.2) in arm A and 54.4 microg x h/ml (range, 23.5-112.2) and 3.0 microg/ml (range, 0.4-7.9) in arm C: GMR arm C:A of 0.52 (99.9% UCB, 0.89) and 0.39 (99.9% UCB, 0.98), respectively (P < or = 0.0008). Ritonavir exposure was not significantly different between arms.. APV and LPV exposures are significantly reduced using LPV/RTV/fosamprenavir, possibly increasing the risk of virologic failure. Consequently, A5143 was closed to enrollment.

Topics: Adult; Carbamates; Drug Interactions; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Male; Middle Aged; Organophosphates; Pyrimidinones; Ritonavir; Salvage Therapy; Sulfonamides; Treatment Outcome

In a controlled, prospective study, the efficacy of ritonavir 200 mg twice daily (bid) in inhibiting the decrease of amprenavir plasma concentrations caused by co-administration of lopinavir was assessed. Twelve HIV-seropositive patients were enrolled, and nine patients completed the 28-day study. At day 14, plasma concentrations of amprenavir 600 mg bid and ritonavir 200 mg bid were determined over 12 h. At day 15, lopinavir 400 mg bid was added. At day 28, plasma concentrations of amprenavir, ritonavir and lopinavir were assessed. Co-administration of lopinavir was found to decrease the amprenavir concentration, determined as the median area under the curve over 12 h (AUC12), by 25% (AUC12 24.9 microg/h/mL vs. 18.5 microg/h/mL; P<0.01), despite the presence of ritonavir 200 mg bid. Eight participants discontinued the study regimen during the first 6 weeks because of adverse gastrointestinal events. In conclusion, gastrointestinal tolerance of a regimen containing an increased dose of ritonavir 200 mg bid was low, while the regimen did not prevent a decrease of amprenavir and possibly lopinavir plasma concentrations.

Topics: Anti-HIV Agents; Carbamates; Drug Interactions; Drug Therapy, Combination; Furans; HIV Protease Inhibitors; HIV Seropositivity; Humans; Lopinavir; Prospective Studies; Pyrimidinones; Ritonavir; Sulfonamides

Coadministration of amprenavir (APV) with small doses of ritonavir (RTV) results in a significant increase in APV plasma concentrations. Viruses showing resistance to other protease inhibitors (PI) may remain susceptible to APV, supporting a role for this drug in salvage therapy. We enrolled 35 patients who began a rescue intervention based on APV/RTV 600/100 mg twice daily. Their median viral load before beginning APV/RTV was 4.15 logs and their median CD4 count was 247 cells per microliter. The median prior PI exposure was of 43 months. At baseline, the median number of PI resistance mutations was 7. A significant virologic response (VR) (>1 log drop in plasma HIV-RNA and/or to <50 copies per milliliter) was recorded in 21.7% (5/23) of treated patients at week 48 (14.3% in the intent-to-treat analysis). The VR was significantly more frequent among subjects with less than 5 PI resistance mutations (66.6% vs. 5.8%; p = 0.008). Patients with prior exposure to lopinavir showed VR significantly less frequently than those not exposed to that drug (11% versus 60%; p < 0.05). The mean APV plasma trough concentration at week 12 was 1.3 microg/mL, and did not differ significantly comparing subjects having or not having VR. A trend toward a higher VR rate at week 48 was noticed among subjects with high genotypic inhibitory quotients (GIQ). In summary, HIV genotyping but not drug levels might be helpful to predict which patients would benefit from a rescue intervention based on APV/RTV 600/100 twice daily.

Topics: Adult; Antiretroviral Therapy, Highly Active; Area Under Curve; Carbamates; CD4 Lymphocyte Count; Drug Administration Schedule; Drug Resistance, Viral; Female; Furans; Genotype; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Lopinavir; Male; Mutation; Patient Selection; Phenotype; Predictive Value of Tests; Prospective Studies; Pyrimidinones; Ritonavir; RNA, Viral; Salvage Therapy; Sulfonamides; Treatment Outcome; Viral Load

To evaluate the safety and pharmacokinetic interaction between GW433908, ritonavir (RTV), and efavirenz (EFV).. In period 1, subjects received either a once daily (QD) regimen of GW433908 1395 mg + RTV 200 mg (Study 1) or a twice daily (bid) regimen of GW433908 700 mg + RTV 100 mg (Study 2) for 14 days. In period 2, subjects received EFV 600 mg QD with either the same GW433908 + RTV regimen as in period 1 (arm 1) or with a GW433908 + RTV regimen that included an additional 100 mg of RTV (arm 2) for 14 days. Amprenavir (APV) pharmacokinetic sampling and safety assessments were performed on the last day of each period.. Plasma APV exposure was not significantly altered when EFV was coadministered with GW433908 700 mg twice daily (BID) + RTV 100 mg BID. Plasma APV exposure was decreased when EFV was coadministered with GW433908 1395 mg QD + RTV 200 mg QD. However, administration of EFV with GW433908 1395 mg QD + RTV 300 mg QD (i.e., adding an extra 100 mg of RTV) was able to negate this interaction. Adverse events were consistent with prior data for each of the separate agents.. When EFV is coadministered with the GW433908 700 mg + RTV 100 mg BID regimen, no dosage adjustment is recommended. However, when EFV is coadministered with the GW433908 1400 mg + RTV 200 mg QD regimen, an increase to RTV 300 mg QD is needed to maintain plasma APV exposure.

Topics: Adult; Alkynes; Anti-HIV Agents; Area Under Curve; Benzoxazines; Carbamates; Cholesterol; Cyclopropanes; Drug Administration Schedule; Drug Interactions; Female; Furans; Humans; Linear Models; Male; Middle Aged; Organophosphates; Oxazines; Prodrugs; Ritonavir; Sulfonamides; Triglycerides

This pharmacokinetic study was designed to characterize interactions between amprenavir and the lopinavir-ritonavir combination in patients infected with human immunodeficiency virus in whom previous antiretroviral therapy had failed.. Twenty-seven patients included in a randomized clinical trial (ANRS [National Agency for AIDS Research] Protocol 104) participated in this study. They were randomized to receive ritonavir at a dose of either 100 mg twice daily or 200 mg twice daily. For the first 2 weeks of therapy, they were randomly assigned to receive lopinavir (400 mg twice daily) and ritonavir (100 mg twice daily), amprenavir (600 mg twice daily) plus ritonavir (100 mg twice daily), lopinavir (400 mg twice daily) and ritonavir (100 mg twice daily) plus additional ritonavir (100 mg twice daily), or amprenavir (600 mg twice daily) plus ritonavir (200 mg twice daily). From week 3 onward, all patients received amprenavir plus lopinavir-ritonavir with or without an additional ritonavir dose (100 mg twice daily). The pharmacokinetics of the 3 drugs was studied in weeks 2 and 6 of therapy.. Median amprenavir concentrations decreased by 54% (P =.004) when lopinavir was added to the amprenavir-ritonavir regimen. Lopinavir weakly displaced amprenavir from plasma proteins: The average unbound fraction of amprenavir was 0.089 in week 2 and 0.114 in week 6 (P =.03), but this did not fully account for the observed interaction. Increasing the ritonavir dose did not affect the amprenavir concentration. The relationship between lopinavir and ritonavir concentrations fitted a maximum effect (E(max)) model;the average concentration of ritonavir that yielded a lopinavir concentration of 8119 ng/mL (50% of E(max)) was 602 ng/mL (coefficient of variation, 22%). There was a significant relationship between the lopinavir inhibitory quotient and the virologic response in week 2 (P =.005).. Lopinavir markedly decreases the amprenavir concentration during amprenavir and lopinavir-ritonavir combination therapy. The inhibitory quotients were more predictive of the short-term virologic response than was the level of drug exposure.

Topics: Administration, Oral; Adult; Antiretroviral Therapy, Highly Active; Biological Availability; Carbamates; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Interactions; Drug Therapy, Combination; Female; Follow-Up Studies; Furans; HIV Infections; Humans; Lopinavir; Male; Maximum Tolerated Dose; Middle Aged; Probability; Pyrimidinones; Risk Assessment; Ritonavir; Salvage Therapy; Severity of Illness Index; Single-Blind Method; Statistics, Nonparametric; Sulfonamides; Survival Rate; Treatment Outcome; Viral Load

The safety, efficacy, and mutual interactions of combination amprenavir with lopinavir/ritonavir as deep salvage treatment were investigated in a prospective 24-week pilot study. HIV-infected patients (n = 22) with virologic failure to nucleoside reverse transcriptase inhibitors (NRTIs), non-NRTIs, and at least 2 protease inhibitors received 400/100 mg of lopinavir/ritonavir with 600 mg of amprenavir every 12 hours combined with NRTIs. Patients receiving the same doses of lopinavir/ritonavir (n = 10) or amprenavir with ritonavir (n = 8) were chosen as controls for pharmacokinetic analyses. Mean changes from baseline HIV RNA levels and CD4 counts after 24 weeks were -1.13 log10 copies/mL and +88 x 10 cells/L, respectively. The mean plasma trough concentration (Cmin)and peak concentration (Cmax) of amprenavir were 104% and 228% lower and the Cmin of lopinavir was 46% lower in patients in whom the drugs were coadministered than in controls. There were 4 permanent drug discontinuations because of toxicity. An inhibitory quotient (IQ) of amprenavir higher than 0.8 was the best predictor of virologic outcome at 24 weeks, even after adjusting for amprenavir Cmin or phenotypic susceptibility. Deep salvage therapy using lopinavir/ritonavir with amprenavir is sufficiently safe and shows partial efficacy. When these drugs are coadministered, therapeutic drug monitoring should be employed and the IQ can be used to determine target drug levels.

Topics: Adult; Anti-HIV Agents; Carbamates; CD4 Lymphocyte Count; Drug Resistance, Viral; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV-1; Humans; Lopinavir; Male; Middle Aged; Pilot Projects; Pyrimidinones; Ritonavir; RNA, Viral; Salvage Therapy; Sulfonamides

The aim of this study was to quantify the change in saquinavir and amprenavir exposure when combined and used with low-dose ritonavir; to evaluate 24-week safety and immunologic and virologic response. It was a randomized, nonblinded, prospective study. There were 11 HIV-1-infected, antiretroviral-experienced, male and female subjects > or = 18 years old, median HIV-1 RNA and CD4(+) T-cell count of 4.86 log copies/mL and 10(6) cells/mm(3), respectively. Subjects were randomly assigned to receive saquinavir 1000 mg/ritonavir 100 mg every 12 hours or amprenavir 600 mg/ritonavir 100 mg every 12 hours for 7 days. After 12-hour pharmacokinetic sampling, the third protease inhibitor (PI) was added, and pharmacokinetics sampling was repeated 14 days later. Subsequent PI dosage adjustments were based on real-time pharmacokinetic assessment. Saquinavir did not affect amprenavir or ritonavir pharmacokinetics. Amprenavir decreased area under the concentration-time curve (AUC(0-12h)) and C(12h) for saquinavir 82 and 61%, and 74 and 75% for ritonavir. An adjusted PI regimen of amprenavir 600 mg/saquinavir 1400 mg/ritonavir 200 mg every 12 hours returned saquinavir exposure to baseline. At 24 weeks, HIV RNA declined a median of 1.55 log copies/mL and CD4(+) T-cell counts increased a median of 52 cells/mm(3). Gastrointestinal events predominated and were mild to moderate. These data suggest that amprenavir/saquinavir/ritonavir may be a viable salvage regimen in heavily PI-experienced individuals. New formulations of amprenavir and saquinavir may simplify this regimen.

Topics: Adult; Carbamates; CD4 Lymphocyte Count; Drug Administration Schedule; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Male; Middle Aged; Ritonavir; Salvage Therapy; Saquinavir; Sulfonamides; Viral Load

To compare the safety and efficacy of amprenavir [APV/j Agenerase trade mark; GlaxoSmithKline, [Ware, UK; 600 mg twice a day (bid)] boosted with low-dose ritonavir (RTV, 100 mg bid) with those of other protease inhibitors (PIs) in PI-experienced HIV-infected patients.. Parallel-group, randomized, open-label, multicentre study.. One hundred and sixty-three patients with HIV predicted to be sensitive to APV, another PI and a nucleoside reverse transcriptase inhibitor (NRTI) were randomly assigned to receive either APV boosted with low-dose RTV (APV/r) or a standard of care (SOC) PI with or without low-dose RTV. The non-inferiority of APV/r to the SOC PIs was assessed by time-weighted average change from baseline (AAUCMB) in plasma viral load (vRNA) at week 16.. The antiviral response for APV/r bid was non-inferior to that for the SOC PI group: the vRNA AAUCMB mean treatment difference was 0.043 log(10) HIV-1 RNA copies/mL [95% confidence interval (CI)-0.250, 0.335]. APV/r bid was generally well tolerated.. Results confirm the antiviral activity, short-term safety and tolerability of APV/r bid in PI-experienced patients.

Topics: Adolescent; Adult; Aged; Anti-HIV Agents; Carbamates; Female; Furans; Genes, Viral; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Male; Middle Aged; Ritonavir; Sulfonamides

The pharmacokinetics, antiviral activity, and safety of an amprenavir-ritonavir (APV-RTV) 600/100 mg b.i.d. regimen and an APV-RTV 1200/200 mg q.d. regimen were studied in a human immunodeficiency virus (HIV)-infected population. The geometric least-square mean ratio (90% confidence interval) of steady-state trough concentrations, compared with that of the amprenavir 1200 mg b.i.d. regimen, was 6.08 (4.94-7.49) for the twice-daily APV-RTV regimen, and it was 4.19 (2.90-6.08) for the daily APV-RTV regimen. The regimens were well tolerated, which supports APV-RTV as an option for twice-daily or daily therapy for HIV.

Topics: Adolescent; Adult; Aged; Antiretroviral Therapy, Highly Active; Carbamates; Female; Furans; HIV Infections; Humans; Male; Middle Aged; Ritonavir; Sulfonamides

To compare the antiviral efficacy of a salvage therapy combining lopinavir and amprenavir with 200 mg/d or 400 mg/d ritonavir, together with nucleoside reverse transcriptase inhibitors, over a 26-week period in HIV-infected patients in whom multiple antiretroviral regimens had failed.. Phase IIb, randomized, open-label, multicentre trial. Patients were eligible if they had <500 CD4+ cells/mm3 and >4 log10 copies/ml HIV-RNA after treatment with at least two protease inhibitors (PIs) and one non-nucleoside reverse transcriptase inhibitor.. At baseline (n=37), the median CD4+ cell count was 207/mm3 and the median plasma HIV-1 RNA level was 4.7 log10 copies/ml; the median number of PI mutations was seven and the median decrease in phenotypic susceptibility to lopinavir and amprenavir was 9.7 and 2.6, respectively. The mean number of antiretrovirals received prior to randomization was 7.7. The fall in the median HIV-1 RNA level at week 26 was -1.4 log10 copies/ml in the 200 mg/d ritonavir group and -2.5 log10 copies/ml in the 400 mg/d group (P=0.02). Viral load fell below 50 copies/ml in 32% and 61% of patients, respectively (P=0.07). After adjustment for the ritonavir dose, a smaller number of PI mutations was the only baseline characteristic associated with a better virological response at week 26. Amprenavir concentrations were significantly lower in presence of lopinavir. The lopinavir inhibitory quotient at week 6 correlated weakly with the change in the HIV-RNA level at week 26.. Combination of amprenavir, lopinavir and 400 mg/d ritonavir shows significant virological efficacy without increased toxicity in HIV-infected patients in whom multiple antiretroviral regimens have failed.

Topics: Adult; Aged; Carbamates; Drug Administration Schedule; Drug Therapy, Combination; Female; France; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Lopinavir; Male; Middle Aged; Pyrimidinones; Ritonavir; RNA, Viral; Salvage Therapy; Sulfonamides; Viral Load

The protease inhibitor (PI) ritonavir is used as a strong inhibitor of cytochrome P450 3A4, which boosts the activities of coadministered PIs, resulting in augmented plasma PI levels, simplification of the dosage regimen, and better efficacy against resistant viruses. The objectives of the present open-label, multiple-dose study were to determine the steady-state pharmacokinetics of amprenavir administered at 600 mg twice daily (BID) and ritonavir administered at 100 mg BID in human immunodeficiency virus type 1 (HIV-1)-infected adults treated with different antiretroviral combinations including or not including a nonnucleoside reverse transcriptase inhibitor (NNRTI). Nineteen patients completed the study. The steady-state mean minimum plasma amprenavir concentration (C(min,ss)) was 1.92 microg/ml for patients who received amprenavir and ritonavir without an NNRTI and 1.36 microg/ml for patients who received amprenavir and ritonavir plus efavirenz. For patients who received amprenavir-ritonavir without an NNRTI, the steady-state mean peak plasma amprenavir concentration (C(max,ss)) was 7.12 microg/ml, the area under the concentration-time curve from 0 to 10 h (AUC(0-10)) was 32.06 microg. h/ml, and the area under the concentration-time curve over a dosing interval (12 h) at steady-state (AUC(ss)) was 35.74 microg. h/ml. Decreases in the mean values of C(min,ss) (29%), C(max,ss) (42%), AUC(0-10) (42%), and AUC(ss) (40%) for amprenavir occurred when efavirenz was coadministered with amprenavir-ritonavir. No unexpected side effects were observed. As expected, coadministration of amprenavir with ritonavir resulted in an amprenavir C(min,ss) markedly higher than those previously reported for the marketed dose of amprenavir. When amprenavir-ritonavir was coadministered with efavirenz, amprenavir-ritonavir maintained a mean amprenavir C(min,ss) above the mean 50% inhibitory concentration of amprenavir previously determined for both wild-type HIV-1 isolates and HIV-1 strains isolated from PI-experienced patients. These data support the use of low-dose ritonavir to enhance the level of exposure to amprenavir and increase the efficacy of amprenavir.

Topics: Adult; Alkynes; Area Under Curve; Benzoxazines; Carbamates; Cyclopropanes; Drug Administration Schedule; Drug Therapy, Combination; Female; Furans; Half-Life; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Male; Oxazines; Ritonavir; Sulfonamides

Forty-nine protease inhibitor (PI)-experienced but amprenavir (APV)-naïve patients experiencing virological failure were treated with ritonavir (RTV) (100 mg twice a day [b.i.d.]) plus APV (600 mg b.i.d.). Patients responded to therapy with a median viral load decrease of -1.32 log(10) by week 12. The addition of low-dose RTV enhanced the minimal APV concentration in plasma (APV C(min)) up to 10-fold compared with that obtained with APV (1,200 mg b.i.d.) without RTV. Baseline PI resistance mutations (L10F/I/V, K20M/R, E35D, R41K, I54V, L63P, V82A/F/T/S, I84V) identified by univariate analysis and included in a genotypic score and APV C(min) at week 8 were predictive of the virological response at week 12. The response to APV plus RTV was significantly reduced in patients with six or more of the resistance mutations among the ones defined above. The genotypic inhibitory quotient, calculated as the ratio of the APV C(min) to the number of human immunodeficiency virus type 1 protease mutations, was a better predictor than the virological or pharmacological variables used alone. This genotypic inhibitory quotient could be used in therapeutic drug monitoring to define the concentrations in plasma needed to control replication of viruses with different levels of PI resistance, as measured by the number of PI resistance mutations.

Topics: Adult; Carbamates; Drug Administration Schedule; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Male; Middle Aged; Predictive Value of Tests; Ritonavir; Sulfonamides; Viral Load

Treatment failure after preceding protease inhibitors (PI) is often due to resistance mutations. Our objective was to evaluate amprenavir (APV) in pre-treated patients and to correlate it with pre-existing mutations. - Fourty five patients were entered in an open label prospective study (6/99-12/2000). Pre-treatment was 6.2 years +/- 2.4 (2-11.3) and included a mean of 4.13 nucleosides (RTIs) and 2.73 PIs. Genotypic resistance testing was performed prior to the switch. APV dose was 1200 mg/d in combination with ritonavir (RTV) boosting (2 x 100mg) and 2 x 1200 mg/d in 6 patients without RTV. Co-medication was selected based on treatment history and results of genotypic testing. - The median duration of treatment at analysis was 34 weeks. Plasma viral load (VL) average at baseline was 4.6 log subset 10 +/- 08. After 24 weeks the mean VL reduction was 1.4 log subset 10 +/- 1.2 3.86-0.40s). A VL reduction of >1.5 log subset 10 was found in 16/45 patients (36%), 21/45 (47%) patients achieved a VL <400 cp/ml, and 12/45 (27%) a VL < 50 cp/ml. CD4 cells increased from a mean baseline of 208/microl +/- 185 to 318/microl +/- 253. Fourty percent (18/45) of patients had a CD4 gain of more than 100 cells/microl. Genotypic resistance determination showed PI mutations in 87% of patients tested. The average number of mutated codons was 4.54. Three of 4 patients with I84V mutation did not achieve an undetectable VL. - Our findings demonstrate that APV and APV/RTV plus two additional antiretrovirals has a good virological and immunological success rate in pre-treated patients. Presence of more than two APV resistance mutations was associated with treatment failure.

Topics: Anti-HIV Agents; Carbamates; CD4 Lymphocyte Count; Drug Resistance, Viral; Drug Therapy, Combination; Female; Furans; Genotype; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Mutation; Prospective Studies; Ritonavir; Sulfonamides; Treatment Outcome; Viral Load; Viremia

Low-dose ritonavir (RTV) boosts plasma amprenavir (APV) exposure. Little has been published on the efficacy, tolerability, and safety of APV 600 mg/RTV 100 mg (APV600/RTV) twice daily (BID) compared to APV 1200 mg BID (APV1200).. ESS40011 was a 24-week, multicenter, open-label, clinical trial in which antiretroviral therapy-naïve and -experienced HIV-1-infected adults were randomized 3:1 to receive either APV600/RTV BID or APV1200 BID, in combination with > or = 2 non-protease inhibitor antiretroviral drugs. Non-inferiority of the APV600/RTV regimen to the APV1200 regimen was established if the 95% lower confidence limit for the difference in proportion of patients achieving HIV-1 RNA <200 copies/mL at week 24 with APV 600/RTV minus APV1200 was > or =-0.12. Late in the conduct of the trial, patients not yet completing 24 weeks of therapy were given the option of continuing treatment for an additional 24-week period.. 211 patients were randomized, 158 to APV600/RTV and 53 to APV1200. At week 24, APV600/RTV was similar to or better than APV1200 (HIV-1 RNA <200 copies/mL in 62% [73/118] vs 53% [20/38] of patients; intent-to-treat: observed analysis). In the APV600/RTV arm, significantly more patients achieved HIV-1 RNA <50 copies/mL (48% [57/118] vs 29% [11/38] with APV1200, P = 0.04), and greater mean reduction from baseline in HIV-1 RNA was observed (-2.21 vs -1.59 log10 copies/mL, P = 0.028). The two treatment arms were similar with respect to mean overall change from baseline in CD4+ count, frequency of drug-related grade 1-4 adverse events, and frequency of discontinuing treatment due to adverse events (most commonly nausea, diarrhea, vomiting or fatigue; 7% vs 8%), although a lower proportion of patients in the APV600/RTV arm experienced drug-related oral/perioral paresthesia (2% vs 8%). Eleven (73%) of 15 patients who had HIV-1 RNA <200 copies/mL at week 24 and chose to continue study treatment maintained this level of virologic suppression at follow-up 24 weeks later.. APV600 RTV BID was similar to or better than APV1200 BID in virologic response. Virologic results in a small number of patients who continued treatment for 24 weeks post-study suggest that virologic suppression with APV600 RTV BID is durable.

Topics: Adult; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Carbamates; CD4 Lymphocyte Count; Female; Furans; HIV Infections; HIV-1; Humans; Male; Ritonavir; RNA, Viral; Sulfonamides; Viral Load

Enfuvirtide is a novel antiretroviral that blocks HIV-1 cell fusion and viral entry. This Phase II, controlled, open-label, randomized, multicentre dose-ranging trial explored the safety, antiviral activity and pharmacokinetics of enfuvirtide, administered by subcutaneous (s.c.) injection, in 71 HIV-1-infected, protease inhibitor-experienced, non-nucleoside reverse transcriptase inhibitor (NNRTI)-naive adults for 48 weeks. Study participants were randomized to receive enfuvirtide at a deliverable dose of 45, 67.5 or 90 mg twice daily; the 45 mg twice daily dose required 2 injections/day, while the higher doses required 4 injections/day. A background oral antiretroviral (ARV) regimen of abacavir (300 mg twice daily), amprenavir (1200 mg twice daily), ritonavir (200 mg twice daily) and efavirenz (600 mg once daily) was provided with enfuvirtide. A control group received the background ARV regimen alone. All potential participants underwent an HIV genotype at screen to ensure a homogenous population and to exclude patients with evidence of genotypic resistance to NNRTIs. Overall, the tolerability of the combination of abacavir, amprenavir, ritonavir, efavirenz and enfuvirtide was generally comparable to control through 48 weeks. No enfuvirtide dose-dependent adverse events (AEs) were observed across treatment groups. Injection site reactions (ISRs) occurred at least once in 68.5% of the enfuvirtide-treated population, and most ISRs were mild to moderate in severity, with no apparent dose relationship. Excluding ISRs, the most common treatment-emergent AEs were nausea, diarrhoea, dizziness and fatigue; with no clinically significant differences in the incidence of AEs observed between the control and enfuvirtide groups. Each treatment group benefited from ARV therapy, with a trend of increasing antiviral and immunological activity associated with increasing enfuvirtide dose. At 48 weeks, the median HIV-1 RNA change from baseline for the ITT population was -2.24 log10 copies/ml for the combined enfuvirtide groups compared with -1.87 log10 copies/ml for the control group. In addition, 54.9% of patients in the enfuvirtide group achieved HIV-1 RNA < or = 400 copies/ml versus 36.8% of patients in the control group. These results indicate that enfuvirtide has a favourable safety profile and is a promising new antiviral agent for HIV-infected patients who have been on previously failing ARV regimens.

Topics: Adult; Alkynes; Anti-HIV Agents; Benzoxazines; Carbamates; Cyclopropanes; Dideoxynucleosides; Drug Therapy, Combination; Enfuvirtide; Female; Furans; HIV Envelope Protein gp41; HIV Fusion Inhibitors; HIV Infections; HIV-1; Humans; Male; Middle Aged; Oxazines; Peptide Fragments; Reverse Transcriptase Inhibitors; Ritonavir; Sulfonamides; Treatment Outcome; Viral Load

The study objective was to evaluate the pharmacodynamics of amprenavir in an in vitro system, develop an exposure target for maximal viral suppression, and determine the likelihood of target attainment based on the pharmacokinetics of amprenavir and ritonavir in human immunodeficiency virus (HIV)-infected patients. Population pharmacokinetic data were obtained from 13 HIV-infected patients receiving amprenavir and ritonavir in doses of 600 and 100 mg, respectively, every 12 h. A 2,500-subject Monte Carlo simulation was performed. Target attainment was also estimated for a target derived from clinical data. Maximal viral suppression (in vitro) was achieved when amprenavir free-drug concentrations remained greater than four times the 50% effective concentration (EC(50)) for 80% of the dosing interval. At an amprenavir EC(50) of 0.03 microM, the likelihood of target attainment is 97.4%. For reduced-susceptibility isolates for which the EC(50)s are 0.05 and 0.08 microM, target attainment is 91.0 and 75.8%, respectively. For the clinical target of a trough concentration/EC(50) ratio of 5, the target attainment rates were similar. Treatment with amprenavir and ritonavir at doses of 600 and 100 mg, respectively, twice a day provides excellent suppression of wild-type isolates and reduced-susceptibility isolates up to an EC(50) of 0.05 micro M. Even at 0.12 microM, target attainment likelihood exceeds 50%, making this an option for patients with extensive exposure to protease inhibitors when this treatment is used with additional active antiretroviral agents.

Topics: Adult; Anti-HIV Agents; Antiviral Agents; Carbamates; Cell Line; Cells, Cultured; Drug Combinations; Female; Furans; HIV Antigens; Humans; Male; Middle Aged; Models, Biological; Protein Binding; Ritonavir; Sulfonamides; T-Lymphocytes; Tetrazolium Salts; Thiazoles; Time Factors

Data from three pharmacokinetic drug interaction studies of amprenavir and ritonavir were used to develop a pharmacokinetic interaction model using NONMEM (nonlinear mixed-effect model). A two-compartment linear model with first-order absorption best fit the amprenavir data, while a one-compartment model was used to describe the ritonavir data. The inhibition of elimination of amprenavir by ritonavir was modeled with a maximum effect (Emax) inhibition model and the observed ritonavir concentration. Monte Carlo simulation was then used to predict amprenavir concentrations for various combinations of amprenavir and ritonavir in twice-daily and once-daily dosing regimens. Simulated minimum amprenavir concentrations in plasma (Cmin) in twice-daily and once-daily dosing regimens were compared with protein binding-adjusted 50% inhibitory concentrations (IC50s) for clinical human immunodeficiency virus isolates with different susceptibilities to protease inhibitors (central tendency ratios). The model based on the first two studies predicted the results of the third study. Data from all three studies were then combined to refine the final model. The observed and simulated noncompartmental pharmacokinetic parameters agreed well. From this model, several candidate drug regimens were simulated. These simulations suggest that, in patients who have clinically failed a traditional amprenavir regimen, a regimen of 600 mg of amprenavir with 100 mg of ritonavir twice daily would result in Cmin-to-IC50 ratios similar to that of 1,200 mg of amprenavir twice daily alone for wild-type viruses. In addition, once-daily regimens that result in C(min)s above the protein binding-corrected IC50s for wild-type virus are clearly feasible.

Topics: Adolescent; Adult; Algorithms; Anti-HIV Agents; Carbamates; Computer Simulation; Drug Interactions; Female; Furans; Humans; Male; Middle Aged; Models, Biological; Monte Carlo Method; Reproducibility of Results; Ritonavir; Sulfonamides

To evaluate the safety and pharmacokinetic interaction between amprenavir (APV) and ritonavir (RTV).. Three open-label, randomized, two-sequence, multiple-dose studies having the same design (7 days of APV or RTV alone followed by 7 days of both drugs together) used 450 or 900 mg APV with 100 or 300 mg RTV every 12 h with pharmacokinetic assessments on days 7 and 14. Safety was monitored as clinical adverse events (AEs) and laboratory abnormalities.. Relative to APV alone, RTV co-administration resulted in a 3.3- to 4-fold and 10.84 to 14.25-fold increase in the geometric least-square (GLS) mean area under the plasma concentration--time curve (AUC(tau,ss)) and minimum concentration (C(min,ss)), respectively. APV 900 mg with RTV 100 mg resulted in a 2.09-fold and 6.85-fold increase in the GLS mean AUC(tau,ss) and C(min,ss), respectively. On day 14, the geometric mean (95% confidence interval) for 450 mg APV AUC(tau,ss) (micro x h/mL) was 23.49 (19.32--28.57) with 300 mg RTV and 35.42 (30.46--44.42) with 100 microg RTV, and for the 900 mg APV with 100 mg RTV 47.11 (39.47--61.24). The 450 mg APV C(min,ss) (microg/ml) were 1.32 (1.05--1.67) and 2.01 (1.70--2.61), and 2.47 (2.08--3.32) for 900 mg APV. The most common AEs were mild and included diarrhea, nausea/vomiting, oral parasthesias, and rash. The triglyceride and cholesterol increased significantly from RTV exposure.. Adding RTV to APV resulted in clinically and statistically significant increases in APV AUC and C(min) with variable effects on maximum concentration. The two RTV doses had similar effects on APV but AEs were more frequent with 300 mg RTV.

Topics: Administration, Oral; Adult; Body Mass Index; Carbamates; Diarrhea; Dose-Response Relationship, Drug; Drug Therapy, Combination; Exanthema; Female; Furans; HIV Protease Inhibitors; HIV Seronegativity; Humans; Male; Middle Aged; Nausea; Ritonavir; Statistics, Nonparametric; Sulfonamides

The extent to which human immunodeficiency virus (HIV) type 1 drug resistance compromises therapeutic efficacy is intimately tied to drug potency and exposure. Most HIV-1 protease inhibitors maintain in vivo trough levels above their human serum protein binding-corrected IC(95) values for wild-type HIV-1. However, these troughs are well below corrected IC(95) values for protease inhibitor-resistant viruses from patients experiencing virologic failure of indinavir and/or nelfinavir. This suggests that none of the single protease inhibitors would be effective after many cases of protease inhibitor failure. However, saquinavir, amprenavir, and indinavir blood levels are increased substantially when each is coadministered with ritonavir, with 12-h troughs exceeding corrected wild-type IC(95) by 2-, 7-, and 28-79-fold, respectively. These indinavir and amprenavir troughs exceed IC(95) for most protease inhibitor-resistant viruses tested. This suggests that twice-daily indinavir-ritonavir and, to a lesser extent, amprenavir-ritonavir may be effective for many patients with viruses resistant to protease inhibitors.

Topics: Carbamates; Drug Resistance, Microbial; Drug Synergism; Drug Therapy, Combination; Furans; Genotype; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Nelfinavir; Phenotype; Protein Binding; Ritonavir; Saquinavir; Sulfonamides

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.

Topics: Carbamates; Drug Resistance, Microbial; Drug Synergism; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Isoquinolines; Pyridines; Quinolines; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sulfonamides; Thiazoles; Valine

Topics: Antifungal Agents; Aspartic Acid Proteases; Carbamates; Dose-Response Relationship, Drug; Furans; HIV Protease Inhibitors; Humans; Lopinavir; Macrophages; Microbial Sensitivity Tests; Molecular Structure; Phialophora; Ritonavir; Structure-Activity Relationship; Sulfonamides

Infection by human immunodeficiency virus type 1 (HIV-1) not only destroys the immune system bringing about acquired immune deficiency syndrome (AIDS), but also induces serious neurological diseases including behavioral abnormalities, motor dysfunction, toxoplasmosis, and HIV-1 associated dementia. The emergence of HIV-1 multidrug-resistant mutants has become a major problem in the therapy of patients with HIV-1 infection. Focusing on the wild type (WT) and G48T/L89M mutated forms of HIV-1 protease (HIV-1 PR) in complex with amprenavir (APV), indinavir (IDV), ritonavir (RTV), and nelfinavir (NFV), we have investigated the conformational dynamics and the resistance mechanism due to the G48T/L89M mutations by conducting a series of molecular dynamics (MD) simulations and free energy (MM-PBSA and solvated interaction energy (SIE)) analyses. The simulation results indicate that alterations in the side-chains of G48T/L89M mutated residues cause the inner active site to increase in volume and induce more curling of the flap tips, which provide the main contributions to weaker binding of inhibitors to the HIV-1 PR. The results of energy analysis reveal that the decrease in van der Waals interactions of inhibitors with the mutated PR relative to the wild-type (WT) PR mostly drives the drug resistance of mutations toward these four inhibitors. The energy decomposition analysis further indicates that the drug resistance of mutations can be mainly attributed to the change in van der Waals and electrostatic energy of some key residues (around Ala28/Ala28' and Ile50/Ile50'). Our work can give significant guidance to design a new generation of anti-AIDS inhibitors targeting PR in the therapy of patients with HIV-1 infection.

Topics: Anti-HIV Agents; Carbamates; Drug Resistance; Furans; HIV Protease; Indinavir; Molecular Conformation; Molecular Dynamics Simulation; Mutation; Nelfinavir; Protein Binding; Ritonavir; Sulfonamides

Aspartic peptidase inhibitors have shown antimicrobial action against distinct microorganisms. Due to an increase in the occurrence of Chagas' disease/AIDS co-infection, we decided to explore the effects of HIV aspartic peptidase inhibitors (HIV-PIs) on Trypanosoma cruzi, the etiologic agent of Chagas' disease.. HIV-PIs presented an anti-proliferative action on epimastigotes of T. cruzi clone Dm28c, with IC50 values ranging from 0.6 to 14 µM. The most effective inhibitors, ritonavir, lopinavir and nelfinavir, also had an anti-proliferative effect against different phylogenetic T. cruzi strains. The HIV-PIs induced some morphological alterations in clone Dm28c epimastigotes, as reduced cell size and swollen of the cellular body. Transmission electron microscopy revealed that the flagellar membrane, mitochondrion and reservosomes are the main targets of HIV-PIs in T. cruzi epimastigotes. Curiously, an increase in the epimastigote-into-trypomastigote differentiation process of clone Dm28c was observed, with many of these parasites presenting morphological alterations including the detachment of flagellum from the cell body. The pre-treatment with the most effective HIV-PIs drastically reduced the interaction process between epimastigotes and the invertebrate vector Rhodnius prolixus. It was also noted that HIV-PIs induced an increase in the expression of gp63-like and calpain-related molecules, and decreased the cruzipain expression in epimastigotes as judged by flow cytometry and immunoblotting assays. The hydrolysis of a cathepsin D fluorogenic substrate was inhibited by all HIV-PIs in a dose-dependent manner, showing that the aspartic peptidase could be a possible target to these drugs. Additionally, we verified that ritonavir, lopinavir and nelfinavir reduced drastically the viability of clone Dm28c trypomastigotes, causing many morphological damages.. The results contribute to understand the possible role of aspartic peptidases in T. cruzi physiology, adding new in vitro insights into the possibility of exploiting the use of HIV-PIs in the clinically relevant forms of the parasite.

Topics: Animals; Anti-HIV Agents; Aspartic Acid Proteases; Carbamates; Furans; Host-Parasite Interactions; Indinavir; Insect Vectors; Lopinavir; Microscopy, Electron, Transmission; Nelfinavir; Protease Inhibitors; Ritonavir; Saquinavir; Sulfonamides; Trypanocidal Agents; Trypanosoma cruzi

We report that GRL-0519, a novel nonpeptidic human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) containing tris-tetrahydrofuranylurethane (tris-THF) and a sulfonamide isostere, is highly potent against laboratory HIV-1 strains and primary clinical isolates (50% effective concentration [EC50], 0.0005 to 0.0007 μM) with minimal cytotoxicity (50% cytotoxic concentration [CC50], 44.6 μM). GRL-0519 blocked the infectivity and replication of HIV-1NL4-3 variants selected by up to a 5 μM concentration of ritonavir, lopinavir, or atazanavir (EC50, 0.0028 to 0.0033 μM). GRL-0519 was also potent against multi-PI-resistant clinical HIV-1 variants isolated from patients who no longer responded to existing antiviral regimens after long-term antiretroviral therapy, highly darunavir (DRV)-resistant variants, and HIV-2ROD. The development of resistance against GRL-0519 was substantially delayed compared to other PIs, including amprenavir (APV) and DRV. The effects of nonspecific binding of human serum proteins on GRL-0519's antiviral activity were insignificant. Our analysis of the crystal structures of GRL-0519 (3OK9) and DRV (2IEN) with protease suggested that the tris-THF moiety, compared to the bis-THF moiety present in DRV, has greater water-mediated polar interactions with key active-site residues of protease and that the tris-THF moiety and paramethoxy group effectively fill the S2 and S2' binding pockets, respectively, of the protease. The present data demonstrate that GRL-0519 has highly favorable features as a potential therapeutic agent for treating patients infected with wild-type and/or multi-PI-resistant variants and that the tris-THF moiety is critical for strong binding of GRL-0519 to the HIV protease substrate binding site and appears to be responsible for its favorable antiretroviral characteristics.

Topics: Amino Acid Sequence; Atazanavir Sulfate; Binding Sites; Carbamates; Cell Line, Tumor; Darunavir; Drug Resistance, Viral; Furans; HIV Protease; HIV Protease Inhibitors; HIV-1; Humans; Inhibitory Concentration 50; Lopinavir; Molecular Docking Simulation; Molecular Sequence Data; Oligopeptides; Protein Binding; Pyridines; Ritonavir; Structure-Activity Relationship; Sulfonamides; T-Lymphocytes; Virus Replication

Although HIV protease inhibitors (PIs) produce profound metabolic interactions through inactivation/inhibition of CYP3A enzymes, their role as victims of transporter-based drug-drug interactions (DDIs) is less well understood. Therefore, this study investigated if the PIs, nelfinavir (NFV), ritonavir (RTV), lopinavir (LPV) or amprenavir (APV) were transported into sandwich-cultured human hepatocytes (SCHH), and whether OATPs contributed to this transport. The findings showed that, except for (3) H-APV, no significant decrease in the total hepatocyte accumulation of the (3) H-PIs was detected in the presence of the corresponding unlabeled PI, indicating that the uptake of the other PIs was not mediated. Further, hepatocyte biliary efflux studies using (3) H-APV and unlabeled APV confirmed this decrease to be due to inhibition of sinusoidal influx transporter(s) and not the canalicular efflux transporters. Moreover, this sinusoidal transport of APV was not OATP-mediated. The results indicate that the hepatic uptake of NFV, RTV or LPV was primarily mediated by passive diffusion. The hepatic uptake of APV was mediated by an unidentified sinusoidal transporter(s). Therefore, NFV, RTV or LPV will not be victims of DDIs involving inhibition of hepatic influx transporters; however, the disposition of APV may be affected if its sinusoidal transport is inhibited.

Topics: Carbamates; Cells, Cultured; Drug Interactions; Furans; Hepatocytes; HIV Protease Inhibitors; Humans; Lopinavir; Nelfinavir; Organic Anion Transporters; Ritonavir; Sulfonamides

To predict and determine whether the protease inhibitors (PIs) nelfinavir, amprenavir, atazanavir, ritonavir, and saquinavir could serve as metabolic inhibitors of the human CES1 (hCES1) using both molecular modeling techniques and in vitro inhibition assays.. Initially, a molecular modeling approach was utilized to predict whether the selected PIs could serve as hCES1 inhibitors. The inhibitory effects of these PIs on hCES1 activity were then further evaluated utilizing previously established in vitro assay.. Pharmacophore and 2D-QSAR modeling predicted that nelfinavir would serve as a potent hCES1 inhibitor. This hypothesis was validated by in vitro hCES1 inhibition studies. Other PIs (amprenavir, atazanavir, ritonavir, saquinavir) were evaluated and also shown to be hCES1 inhibitors in vitro, although substantially less potent relative to nelfinavir.. Computational molecular modeling is a valid approach to identify potential hCES1 inhibitors as candidates for further assessment using validated in vitro techniques. DDIs could occur when nelfinavir is co-administered with drugs metabolized by hCES1.

Topics: Antiviral Agents; Atazanavir Sulfate; Carbamates; Carboxylic Ester Hydrolases; Drug Interactions; Furans; Humans; Kinetics; Models, Molecular; Nelfinavir; Oligopeptides; Protease Inhibitors; Pyridines; Quantitative Structure-Activity Relationship; Ritonavir; Saquinavir; Sulfonamides

Malaria and HIV infection are both very common in many developing countries. With the increasing availability of therapy for HIV infection, it was of interest to determine whether antiretroviral drugs exert antimalarial effects. We therefore tested the in vitro activity of 19 antiretroviral drugs against the W2 and 3D7 strains of Plasmodium falciparum at concentrations up to 50 μM. None of 5 tested nucleoside reverse transcriptase inhibitors demonstrated activity. Two nonnucleoside reverse transcriptase inhibitors, efavirenz (mean 50% inhibitory concentration [IC(50)] of 22 to 30 μM against the two strains) and etravirine (3.1 to 3.4 μM), were active; nevirapine was not active. Also active were the fusion inhibitor enfuvirtide (6.2 to 7.9 μM) and the entry inhibitor maraviroc (15 to 21 μM). Raltegravir was not active. However, for all active drugs mentioned above, the IC(50)s were considerably greater than the concentrations achieved with standard dosing. The effects most likely to be clinically relevant were with HIV protease inhibitors. Of the tested compounds, activity was seen with lopinavir (2.7 to 2.9 μM), atazanavir (3.3 to 13.0 μM), saquinavir (5.0 to 12.1 μM), nelfinavir (6.5 to 12.1 μM), ritonavir (9.5 to 10.9 μM), tipranavir (15.5 to 22.3 μM), and amprenavir (28.1 to 40.8) but not darunavir. Lopinavir was active at levels well below those achieved with standard dosing of coformulated lopinavir-ritonavir. Lopinavir also demonstrated modest synergy with the antimalarial lumefantrine (mean fractional inhibitory concentration index of 0.66 for W2 and 0.53 for 3D7). Prior data showed that lopinavir-ritonavir also extends the pharmacokinetic exposure of lumefantrine. Thus, when used to treat HIV infection, lopinavir-ritonavir may have clinically relevant antimalarial activity and also enhance the activity of antimalarials.

Topics: Alkynes; Animals; Anti-Retroviral Agents; Antimalarials; Benzoxazines; Carbamates; Cyclopropanes; Darunavir; Furans; Lopinavir; Nelfinavir; Nevirapine; Plasmodium falciparum; Pyridines; Pyrones; Ritonavir; Saquinavir; Sulfonamides

Patterns of HIV-1 protease inhibitor (PI) resistance-associated mutations (RAMs) and effects on PI susceptibility associated with the L76V mutation were studied in a large database. Of 20,501 sequences with ≥1 PI RAM, 3.2% contained L76V; L76V was alone in 0.04%. Common partner mutations included M46I, I54V, V82A, I84V, and L90M. L76V was associated with a 2- to 6-fold decrease in susceptibility to lopinavir, darunavir, amprenavir, and indinavir and a 7- to 8-fold increase in susceptibility to atazanavir and saquinavir.

Topics: Antiviral Agents; Carbamates; Darunavir; Furans; HIV Protease; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Mutation; Pyrimidinones; Sulfonamides

Human immunodeficiency virus (HIV) protease inhibitor (PI)-induced adverse effects have become a serious clinical problem. In addition to their metabolic and cardiovascular complications, these drugs also frequently cause severe gastrointestinal disorders, including mucosal erosions, epithelial barrier dysfunction, and diarrhea. However, the exact mechanisms underlying gastrointestinal adverse effects of HIV PIs remain unknown. This study investigated whether HIV PIs disrupt intestinal epithelial barrier integrity by activating endoplasmic reticulum (ER) stress.. The most commonly used HIV PIs (lopinavir, ritonavir, and amprenavir) were used; their effects on ER stress activation and epithelial paracellular permeability were examined in vitro as well as in vivo using wild-type and CHOP(-)/(-) mice.. Treatment with lopinavir and ritonavir, but not amprenavir, induced ER stress, as indicated by a decrease in secreted alkaline phosphatase activities and an increase in the unfolded protein response. This activated ER stress partially impaired the epithelial barrier integrity by promoting intestinal epithelial cell apoptosis. CHOP silencing by specific small hairpin RNA prevented lopinavir- and ritonavir-induced barrier dysfunction in cultured intestinal epithelial cells, whereas CHOP(-)/(-) mice exhibited decreased mucosal injury after exposure to lopinavir and ritonavir.. HIV PIs induce ER stress and activate the unfolded protein response in intestinal epithelial cells, thus resulting in disruption of the epithelial barrier integrity.

Topics: Animals; Apoptosis; Carbamates; Cell Line; Cell Membrane Permeability; Endoplasmic Reticulum; Furans; HIV Infections; HIV Protease Inhibitors; Intestinal Mucosa; Lopinavir; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Pyrimidinones; Ritonavir; Stress, Physiological; Sulfonamides; Transcription Factor CHOP

A major problem in the antiretroviral treatment of HIV-infections with protease-inhibitors is the emergence of resistance, resulting from the occurrence of distinct mutations within the protease molecule. In the present work we investigated the structural properties of a triple mutant (I54V-V82A-L90M) and a double mutant (V82A-L90M) that both confer strong resistance to ritonavir (RTV), but not to amprenavir (APV). For the unliganded double mutant protease molecular dynamics simulations revealed a contraction of the ligand binding pocket, which is enhanced by the I54V mutation. The observed displacement of backbone atoms of the 80s loops (residues 80-85 and 80'-85' of the dimer) was found to primarily affect binding of the larger RTV molecule. The pocket contraction detected for the unbound protease upon mutation is also observed in the presence of APV, but not of RTV. As a consequence, the protein-ligand contacts lost upon the V82A mutation are restored by 80s loop motions for the APV-bound, but not for the RTV-bound form. RTV binding is therefore both hampered in the initial recognition step due to the poor fit of the bulky inhibitor into the small pocket of the mutant free protease and by the loss of protein-ligand interactions in the RTV-bound protease. The synergistic nature of both effects offers an explanation for the high level of resistance observed. These findings demonstrate that large inhibitors, which tightly bind to wild-type protease, may nevertheless be prone to the emergence of resistance in the presence of particular patterns of mutations. This information should be helpful for the design of novel and more effective drugs, e.g., by targeting different residues or by developing allosteric inhibitors that are capable of regulating protease dynamics.

Topics: Amino Acid Substitution; Binding Sites; Carbamates; Drug Resistance, Viral; Furans; HIV Protease; HIV Protease Inhibitors; Ligands; Models, Molecular; Mutation; Protein Structure, Tertiary; Ritonavir; Sulfonamides

Patients treated with highly active antiretroviral therapy may develop metabolic side effects such as hyperlipidemia, insulin resistance, lipoatrophy and lactic acidosis. The pathophysiology of these metabolic abnormalities is unknown, although some, e.g., lactic acidosis and lipoatrophy, are more associated with nucleoside use while protease inhibitors (PIs) have been shown to contribute to hyperlipidemia and insulin resistance. Identifying new PIs that are not associated with dyslipidemia has been hindered by the lack of mechanistic information and the unavailability of relevant animal models. In order to understand the molecular mechanism behind the hyperlipidemia associated with other protease inhibitors, and to develop a more effective, faster screen for compounds with this liability, we have analyzed expression profiles from PI-treated animals. Previously, we have shown that treatment of rats with ritonavir results in increases in the expression of proteasomal subunit genes in the liver. We show this increase is similar in rats treated with bortezomib, a proteasome inhibitor. In addition, we have treated rats with additional protease inhibitors, including atazanavir, which is associated with lower rates of lipid elevations in the clinic when administered in the absence of ritonavir. Our results indicate a strong correlation between proteasomal induction and lipid elevations, and have allowed us to develop a rapid screen for identifying novel PIs that do not induce the proteasome.

Topics: Animals; Atazanavir Sulfate; Carbamates; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Furans; Gene Expression Profiling; Gene Expression Regulation, Enzymologic; HIV Protease Inhibitors; Hyperlipidemias; Male; Oligonucleotide Array Sequence Analysis; Oligopeptides; Proteasome Endopeptidase Complex; Pyridines; Rats; Rats, Sprague-Dawley; Ritonavir; Sulfonamides

Hepatotoxicity has been reported as a side-effect in some patients on HIV protease inhibitors (PI). Since transporter interaction has been implicated as a mechanism underlying drug-mediated hepatotoxicity and drug-drug interactions, the interaction of PI with the hepatic canalicular efflux transporter ABCC2 (MRP2; multidrug resistance associated protein-2) was studied. Interaction with ABCC2/Abcc2 was evaluated in human and rat sandwich-cultured hepatocytes using 5(6)-carboxy-2',7'-dichlorofluorescein (CDF) as substrate. In rat hepatocytes, interaction with estradiol-17-beta-D-glucuronide (E17G) efflux was also studied. In human hepatocytes, saquinavir, ritonavir and atazanavir were the most efficient inhibitors of ABCC2-mediated biliary excretion of CDF, whereas in rat hepatocytes indinavir, lopinavir and nelfinavir were the most efficient. No species-similarity was found for ABCC2/Abcc2 inhibition. In rat hepatocytes, the effects on Abcc2 were substrate-dependent as inhibition of biliary excretion of E17G was most pronounced for saquinavir (completely blocked), amprenavir (82% inhibition) and indinavir (68% inhibition). In conclusion, several HIV PI showed substantial ABCC2 inhibition, which, combined with the effects of PI on other hepatobiliary disposition mechanisms, will determine the clinical relevance of these in vitro interaction data.

Topics: Animals; Anti-HIV Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Carbamates; Cells, Cultured; Fluoresceins; Furans; Hepatocytes; HIV Protease Inhibitors; Humans; Indinavir; Liver; Multidrug Resistance-Associated Protein 2; Multidrug Resistance-Associated Proteins; Nelfinavir; Rats; Rats, Wistar; Ritonavir; Saquinavir; Sulfonamides

The role of exposure to specific antiretroviral drugs on risk of myocardial infarction in human immunodeficiency virus (HIV)-infected patients is debated in the literature.. To assess whether we confirmed the association between exposure to abacavir and risk of myocardial infarction (MI) and to estimate the impact of exposure to other nucleoside reverse transcriptase inhibitors (NRTIs), protease inhibitors (PIs), and non-NRTIs on risk of MI, we conducted a case-control study nested within the French Hospital Database on HIV. Cases (n = 289) were patients who, between January 2000 and December 2006, had a prospectively recorded first definite or probable MI. Up to 5 controls (n = 884), matched for age, sex, and clinical center, were selected at random with replacement among patients with no history of MI already enrolled in the database when MI was diagnosed in the corresponding case. Conditional logistic regression models were used to adjust for potential confounders.. Short-term/recent exposure to abacavir was associated with an increased risk of MI in the overall sample (odds ratios [ORs], 2.01; 95% confidence interval [CI], 1.11-3.64) but not in the subset of matched cases and controls (81%) who did not use cocaine or intravenous drugs (1.27; 0.64-2.49). Cumulative exposure to all PIs except saquinavir was associated with an increased risk of MI significant for amprenavir/fosamprenavir with or without ritonavir (OR, 1.53; 95% CI, 1.21-1.94 per year) and lopinavir with ritonavir (1.33; 1.09-1.61 per year). Exposure to all non-NRTIs was not associated with risk of MI.. The risk of MI was increased by cumulative exposure to all the studied PIs except saquinavir and particularly to amprenavir/fosamprenavir with or without ritonavir and lopinavir with ritonavir, whereas the association with abacavir cannot be considered causal.

Topics: Adult; Anti-HIV Agents; Carbamates; Case-Control Studies; Cohort Studies; Confidence Intervals; Dideoxynucleosides; Female; France; Furans; HIV Infections; Hospitals, Isolation; Humans; Logistic Models; Male; Middle Aged; Myocardial Infarction; Odds Ratio; Organophosphates; Regression Analysis; Risk; Ritonavir; Sulfonamides

HIV protease inhibitors (HIV PI) reduce morbidity and mortality of HIV infection but cause multiple untoward effects. Because certain HIV PI evoke production of reactive oxygen species (ROS) and volume-sensitive Cl(-) current (I(Cl,swell)) is activated by ROS, we tested whether HIV PI stimulate I(Cl,swell) in ventricular myocytes. Ritonavir and lopinavir elicited outwardly rectifying Cl(-) currents under isosmotic conditions that were abolished by the selective I(Cl,swell)-blocker DCPIB. In contrast, amprenavir, nelfinavir, and raltegravir, an integrase inhibitor, did not modulate I(Cl,swell) acutely. Ritonavir also reduced action potential duration, but amprenavir did not. I(Cl,swell) activation was attributed to ROS because ebselen, an H(2)O(2) scavenger, suppressed ritonavir- and lopinavir-induced I(Cl,swell). Major ROS sources in cardiomyocytes are sarcolemmal NADPH oxidase and mitochondria. The specific NADPH oxidase inhibitor apocynin failed to block ritonavir- or lopinavir-induced currents, although it blocks I(Cl,swell) elicited by osmotic swelling or stretch. In contrast, rotenone, a mitochondrial e(-) transport inhibitor, suppressed both ritonavir- and lopinavir-induced I(Cl,swell). ROS production was measured in HL-1 cardiomyocytes with C-H(2)DCFDA-AM and mitochondrial membrane potential (ΔΨ(m)) with JC-1. Flow cytometry confirmed that ritonavir and lopinavir but not amprenavir, nelfinavir, or raltegravir augmented ROS production, and HIV PI-induced ROS production was suppressed by rotenone but not NADPH oxidase blockade. Moreover, ritonavir, but not amprenavir, depolarized ΔΨ(m). These data suggest ritonavir and lopinavir activated I(Cl,swell) via mitochondrial ROS production that was independent of NADPH oxidase. ROS-dependent modulation of I(Cl,swell) and other ion channels by HIV PI may contribute to some of their actions in heart and perhaps other tissues.

Topics: Action Potentials; Animals; Carbamates; Chloride Channels; Furans; HIV Integrase Inhibitors; HIV Protease Inhibitors; Ion Channel Gating; Lopinavir; Membrane Potential, Mitochondrial; Mitochondria; Myocytes, Cardiac; Nelfinavir; Pyrimidinones; Pyrrolidinones; Rabbits; Raltegravir Potassium; Reactive Oxygen Species; Ritonavir; Sulfonamides; Time Factors

Pulmonary hypertension (PH) is among the complications of HIV infection. Combination antiretroviral therapy may influence the progression of HIV-related PH. Because Akt signaling is a potential molecular target of HIV protease inhibitors (HPIs), we hypothesized that these drugs altered monocrotaline- and hypoxia-induced PH in rats by downregulating the Akt pathway, thereby inhibiting pulmonary artery smooth muscle cell proliferation.. Daily treatment with each of 3 first-generation HPIs (ritonavir 30 mg/kg, amprenavir 100 mg/kg, and nelfinavir 500 mg/kg) started 3 weeks after a subcutaneous monocrotaline injection (60 mg/kg) substantially diminished pulmonary artery pressure, right ventricular hypertrophy, number of muscularized pulmonary vessels, pulmonary arterial wall thickness, and proliferating pulmonary vascular Ki67-labeled cells without affecting vessel caspase 3 staining. HPI treatment partially prevented the development of hypoxia- and monocrotaline-induced PH. Monocrotaline-induced PH was associated with marked activation of Akt signaling in the lungs and proximal pulmonary arteries, with increases in phosphorylated Akt, phosphorylated glycogen-synthase-kinase-3β (GSK3), and phosphorylated endothelial nitric oxide synthase, all of which decreased markedly after treatment with each HPI. In contrast, PH-associated increases in phosphorylated extracellular signal-related kinase 1/2 and myosin light-chain phosphatase were unaltered by the HPIs. The 3 HPIs and the phosphatidylinositol 3-kinase inhibitor LY294002 inhibited platelet-derived growth factor-induced phosphorylation of Akt and GSK3 in cultured pulmonary artery smooth muscle cells and blocked cell proliferation; this last effect was abolished by the GSK3 inhibitor SB216763.. These results support an effect of HPIs on pulmonary vascular remodeling mediated by inhibition of Akt phosphorylation and consequently of pulmonary artery smooth muscle cell proliferation.

Topics: Animals; Animals, Newborn; Antiretroviral Therapy, Highly Active; Antiviral Agents; Blood Pressure; Carbamates; Cell Division; Furans; Hemodynamics; HIV Protease Inhibitors; Hypertension, Pulmonary; Hypoxia; Male; Monocrotaline; Nelfinavir; Pulmonary Artery; Rats; Rats, Wistar; Ritonavir; Sulfonamides

The importance of the active site region aspartyl residues 25 and 29 of the mature HIV-1 protease (PR) for the binding of five clinical and three experimental protease inhibitors [symmetric cyclic urea inhibitor DMP323, nonhydrolyzable substrate analog (RPB) and the generic aspartic protease inhibitor acetyl-pepstatin (Ac-PEP)] was assessed by differential scanning calorimetry. DeltaT(m) values, defined as the difference in T(m) for a given protein in the presence and absence of inhibitor, for PR with DRV, ATV, SQV, RTV, APV, DMP323, RPB, and Ac-PEP are 22.4, 20.8, 19.3, 15.6, 14.3, 14.7, 8.7, and 6.5 degrees C, respectively. Binding of APV and Ac-PEP is most sensitive to the D25N mutation, as shown by DeltaT(m) ratios [DeltaT(m)(PR)/DeltaT(m)(PR(D25N))] of 35.8 and 16.3, respectively, whereas binding of DMP323 and RPB (DeltaT(m) ratios of 1-2) is least affected. Binding of the substrate-like inhibitors RPB and Ac-PEP is nearly abolished (DeltaT(m)(PR)/DeltaT(m)(PR(D29N)) > or = 44) by the D29N mutation, whereas this mutation only moderately affects binding of the smaller inhibitors (DeltaT(m) ratios of 1.4-2.2). Of the nine FDA-approved clinical HIV-1 protease inhibitors screened, APV, RTV, and DRV competitively inhibit porcine pepsin with K(i) values of 0.3, 0.6, and 2.14 microM, respectively. DSC results were consistent with this relatively weak binding of APV (DeltaT(m) 2.7 degrees C) compared with the tight binding of Ac-PEP (DeltaT(m) > or = 17 degrees C). Comparison of superimposed structures of the PR/APV complex with those of PR/Ac-PEP and pepsin/pepstatin A complexes suggests a role for Asp215, Asp32, and Ser219 in pepsin, equivalent to Asp25, Asp25', and Asp29 in PR in the binding and stabilization of the pepsin/APV complex.

Topics: Atazanavir Sulfate; Binding Sites; Binding, Competitive; Calorimetry, Differential Scanning; Carbamates; Crystallography, X-Ray; Darunavir; Furans; HIV Protease; HIV Protease Inhibitors; Humans; Indinavir; Kinetics; Lopinavir; Models, Molecular; Molecular Structure; Mutation; Nelfinavir; Oligopeptides; Pepsin A; Protein Binding; Protein Structure, Tertiary; Pyridines; Pyrimidinones; Pyrones; Ritonavir; Saquinavir; Sulfonamides

Most HPLC-UV methods for therapeutic drug monitoring of anti-HIV drugs have long run times, which reduce their applicability for high-throughput analysis. We developed an ultra-performance liquid chromatography (UPLC)-diode array detection method for the simultaneous quantification of the HIV-protease inhibitors (PIs) amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and tipranavir (TPV), and the nonnucleoside reverse transcriptase inhibitors (NNRTIs) efavirenz and nevirapine.. Solid-phase extraction of 1 mL plasma was performed with Waters HLB cartridges. After 3 wash steps, we eluted the drugs with methanol, evaporated the alcohol, and reconstituted the residue with 50 microL methanol. We injected a 4-microL volume into the UPLC system (Waters ACQUITY UPLC BEH C8 column maintained at 60 degrees C) and used a linear gradient of 50 mmol/L ammonium acetate and 50 mmol/L formic acid in water versus acetonitrile to achieve chromatographic separation of the drugs and internal standard (A-86093). Three wavelengths (215, 240, and 260 nm) were monitored.. All drugs were eluted within 15 min. Calibration curves with concentrations of 0.025-10 mg/L (1.875-75 mg/L for TPV) showed coefficients of determination (r(2)) between 0.993 and 0.999. The lower limits of quantification were well below the trough concentrations reported in the literature. Inter- and intraassay CVs and the deviations between the nominal and measured concentrations were <15%. The method was validated by successful participation in an international interlaboratory QC program.. This method allows fast and simultaneous quantification of all commercially available PIs and NNRTIs for therapeutic drug monitoring.

Topics: Alkynes; Atazanavir Sulfate; Benzoxazines; Carbamates; Chromatography, High Pressure Liquid; Cyclopropanes; Furans; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Nelfinavir; Nevirapine; Oligopeptides; Pyridines; Pyrimidinones; Pyrones; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sensitivity and Specificity; Solid Phase Extraction; Sulfonamides

We report here the first case to add amprenavir to the growing list of antiretroviral drugs associated with urinary stones. The first reported case of a nelfinavir urinary stone was reported in 2002 in a 37-year-old HIV-infected woman. In September 2007, the same female patient was referred to our department with recent onset of right flank pain and recurrent urinary tract infections. Abdominal computed tomography revealed three obstructing stones in the distal right ureter, another stone in the right renal pelvis with hydronephrosis and a stone in the left kidney. After stone retrieval, analysis of the stone by liquid chromatography with mass spectrometry revealed a stone composition of 95% unmodified amprenavir and 5% ritonavir.

Topics: Adult; Anti-HIV Agents; Carbamates; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Ritonavir; Sulfonamides; Tomography, X-Ray Computed; Urinary Calculi

Topics: Carbamates; Darunavir; Drug Resistance, Viral; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Mutation; Reverse Transcriptase Inhibitors; Ritonavir; Sulfonamides; Treatment Failure; Treatment Outcome

The influence of nevirapine or efavirenz co-administration on ritonavir-boosted amprenavir pharmacokinetics was investigated in HIV-infected patients with a population pharmacokinetic approach. The analysis was performed with a population of 61 patients treated with fosamprenavir/ritonavir (700 mg/100 mg twice daily) combined with nucleoside/nucleotide reverse transcriptase inhibitors +/- enfuvirtide and no other antiretroviral drugs (group A, n = 46) or nevirapine (group B, n = 10) or efavirenz (group C, n = 5). No significant increase in amprenavir clearance [mean +/- standard deviation: 22.49 +/- 10.32 (group A) vs. 21.57 +/- 9.62 (group B) vs. 20.15 +/- 5.18 (group C) L/h] and no significant decrease in trough amprenavir plasma concentrations [1.75 +/- 0.95 (group A) vs. 1.82 +/- 0.72 (group B) vs. 1.55 +/- 0.66 (group C) mg/L] were found in groups B and C in comparison with group A, although nevirapine and efavirenz are inductors of protease inhibitors metabolism. These results suggest that fosamprenavir/ritonavir should be used at standard doses of 700 mg/100 mg twice daily when combined with efavirenz or nevirapine.

Topics: Adult; Alkynes; Anti-HIV Agents; Bayes Theorem; Benzoxazines; Carbamates; Cyclopropanes; Drug Therapy, Combination; Female; France; Furans; HIV Infections; Humans; Male; Models, Biological; Nevirapine; Organophosphates; Reverse Transcriptase Inhibitors; Ritonavir; Sulfonamides

Topics: Adult; Anti-HIV Agents; Carbamates; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Male; Middle Aged; Organophosphates; Pyrimidinones; Ritonavir; Sulfonamides

A simple, accurate and fast method was developed for determination of the commonly used HIV protease inhibitors (PIs) amprenavir, indinavir, atazanavir, ritonavir, lopinavir, nelfinavir, M8-nelfinavir metabolite and saquinavir in human plasma. Liquid-liquid extraction was used with hexane/ethylacetate from buffered plasma samples with a borate buffer pH 9.0. Isocratic chromatographic separation of all components was performed on an Allsphere hexyl HPLC column with combined UV and fluorescence detection. Calibration curves were constructed in the range of 0.025-10 mg/l. Accuracy and precision of the standards were all below 15% and the lowest limit of quantitation was 0.025 mg/l. Stability of quality control samples at different temperature conditions was found to be below 20% of nominal values. The advantages of this method are: (1) inclusion and determination of the newly approved atazanavir, (2) simultaneous isocratic HPLC separation of all compounds and (3) increased specificity and sensitivity for amprenavir by using fluorescence detection. This method can be used for therapeutic drug monitoring of all PIs currently commercialised and is now part of current clinical practice.

Topics: Atazanavir Sulfate; Calibration; Carbamates; Chromatography, High Pressure Liquid; Drug Monitoring; Drug Stability; Fluorescence; Furans; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Nelfinavir; Oligopeptides; Pyridines; Pyrimidinones; Reproducibility of Results; Ritonavir; Saquinavir; Sensitivity and Specificity; Sulfonamides; Ultraviolet Rays

An efficient, isocratic high performance liquid chromatography (HPLC) method for determining human immunodeficiency virus (HIV) non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs) in plasma is advantageous for laboratories participating in clinical trials and therapeutic drug monitoring (TDM) programs, or conducting small animal research. The combination of isocratic reversed phase chromatography using an S-3, 3.0 mm x 150 mm column along with low plasma volume (200 microl), rapid liquid-liquid extraction, and detection at a single wavelength (212 nm) over a short run time makes this method valuable. Within and between assay variability ranges from 0.8 to 3.5% and 1.2-6.2%, respectively. Accuracy ranges from 91.0 to 112.8% for four quality controls (50, 100, 1000, and 10,000 ng/ml) for all drugs measured (efavirenz, nevirapine, amprenavir, atazanavir, indinavir, lopinavir, nelfinavir, ritonavir, and saquinavir).

Topics: Alkynes; Atazanavir Sulfate; Benzoxazines; Carbamates; Chromatography, High Pressure Liquid; Cyclopropanes; Furans; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Nelfinavir; Nevirapine; Oligopeptides; Pyridines; Pyrimidinones; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Spectrophotometry, Ultraviolet; Sulfonamides

An accurate, sensitive and simple reverse-phase (RP) high-performance liquid chromatography (HPLC) assay has been developed and validated for the simultaneous quantitative determination of tipranavir with nine other antiretroviral drugs in plasma. A liquid-liquid extraction of the drugs in tert-butylmethylether (TBME) from 200 microL of plasma is followed by a reversed phase gradient HPLC assay with UV detection at 210 nm. The standard curve for the drug was linear in the range of 80-80,000 ng/mL for tipranavir; 10-10,000 ng/mL for nevirapine, indinavir, efavirenz, and saquinavir; and 25-10,000 ng/mL for amprenavir, atazanavir, ritonavir, lopinavir, and nelfinavir. The regression coefficient (r(2)) was greater than 0.998 for all analytes. This method has been fully validated and shown to be specific, accurate and precise. Due to an excellent extraction procedure giving good recovery and a clean baseline, this method is simple, rapid, accurate and provides excellent resolution and peak shape for all analytes. Thus this method is very suitable for therapeutic drug monitoring.

Topics: Alkynes; Anti-HIV Agents; Atazanavir Sulfate; Benzoxazines; Carbamates; Chromatography, High Pressure Liquid; Cyclopropanes; Drug Stability; Furans; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Molecular Structure; Nelfinavir; Nevirapine; Oligopeptides; Oxazines; Pyridines; Pyrimidinones; Pyrones; Reproducibility of Results; Ritonavir; Saquinavir; Sensitivity and Specificity; Spectrophotometry, Ultraviolet; Sulfonamides; Time Factors

In highly experienced HIV-1-infected patients, a ritonavir-boosted darunavir-containing regimen was associated with dramatic immunological and virological efficacy. Patients harbouring viruses with amprenavir-specific resistance profiles, such as I50V or V32I + I47V, failed on a darunavir/ritonavir-containing regimen. These key amprenavir mutations were also selected at the time of failure, suggesting their impact on darunavir efficacy.

Topics: Carbamates; CD4 Lymphocyte Count; Darunavir; Drug Resistance, Viral; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Reverse Transcriptase Inhibitors; Risk Factors; Ritonavir; Sulfonamides; Treatment Failure; Viral Load

The purpose of this study was to evaluate the steady-state pharmacokinetics of amprenavir and ritonavir in HIV-infected patients with different degrees of hepatic impairment.. HIV-positive patients receiving fosamprenavir/ritonavir (700/100 mg twice daily) were included. Patients were classified into three groups: (i) chronic hepatitis; (ii) liver cirrhosis; (iii) normal liver function. Serial blood samples for steady-state amprenavir and ritonavir pharmacokinetics (>14 days on treatment) were collected in the fasting state before the morning dose (C(trough)) and then 1, 2, 3, 4, 6, 8, 10 and 12 h after drug intake. Amprenavir and ritonavir plasma concentrations were determined by HPLC.. Twenty-one HIV-infected patients were included. Seven had chronic hepatitis, eight had liver cirrhosis and six patients were in the control group. Amprenavir AUC(0-12), AUC(0-infinity), C(max) and C(ss) were increased by 50% to 60% in the cirrhotic group when compared with controls, whereas CL/F was decreased by 40%. Patients with chronic hepatitis showed a significant increase in AUC(0-12), C(max) and C(ss) values when compared with controls. Ritonavir pharmacokinetics was different only in cirrhotic patients when compared with controls. Liver function parameters at weeks 4, 12 and 24 were not different from baseline in any of the groups. Overall, a significant correlation between amprenavir AUC(0-12) and total bilirubin values on the day of pharmacokinetic analysis was found (r = 0.64, P = 0.003).. On the basis of these data and also of data available in the literature, it seems reasonable to adapt the dose of fosamprenavir and/or ritonavir exclusively in the presence of adverse events, possibly related to protease inhibitors (i.e. liver toxicity), in subjects with high drug plasma levels. Therapeutic drug monitoring is advised in the management of these patients.

Topics: Adult; Anti-HIV Agents; Area Under Curve; Attention; Bilirubin; Carbamates; Chromatography, High Pressure Liquid; Female; Furans; HIV Infections; Humans; Liver Diseases; Male; Middle Aged; Organophosphates; Plasma; Ritonavir; Sulfonamides; Time Factors

Acute liver toxicity is a frequent adverse event that occurs during antiretroviral therapy and was observed in 6-30% of the patients on treatment, especially in presence of HCV coinfection (Cooper et al., 2002, Maida et al., 2006, Sulkowski et al., 2000). A correlation between HCV-associated liver-fibrosis severity and the risk of HAART associated hepatoxicity has been demonstrated (Aranzabal et al., 2005, Sulkowski et al., 2004). This high liver toxicity rate might be due to increased drug exposure in patients with liver disease (Veronese et al., 2000). It has been reported that patients with chronic hepatitis C show significantly reduced CPY3A4 and CYP2D6 activity in comparison with healthy volunteers (Becquemont et al., 2002). The aim of this study was to evaluate the liver function tests in HCV-co-infected patients treated with fos-amprenavir and ritonavir.

Topics: Adult; Antiviral Agents; Carbamates; Chromatography, High Pressure Liquid; Furans; Hepacivirus; Hepatitis B virus; Hepatitis C, Chronic; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Liver Cirrhosis; Middle Aged; Ritonavir; Sulfonamides; Treatment Outcome

The effects of five HIV protease inhibitors (amprenavir, indinavir, nelfinavir, ritonavir and saquinavir) on cytochrome P450 (CYP) 3A4, 3A5 and 3A7 activities were studied in vitro using testosterone 6beta-hydroxylation in recombinant CYP3A4, CYP3A5 and CYP3A7 enzymes. The protease inhibitors showed differential inhibitory effects on the three CYP3A forms. Ritonavir and saquinavir were non-selective and preferential inhibitors of CYP3A4 and CYP3A5 (K(i) 0.03 microM and 0.6-0.8 microM for ritonavir and saquinavir, respectively), and weaker inhibitors of CYP3A7 (K(i) 0.6 microM and 1.8 microM, respectively). Nelfinavir was a potent and non-selective inhibitor of all three CYP3A forms (K(i) 0.3-0.4 microM). Amprenavir and indinavir preferentially inhibited CYP3A4 (K(i) 0.1 microM and 0.2 microM, respectively), with weaker inhibitory effects on CYP3A5 (K(i) 0.5 microM and 2.2 microM, respectively) and CYP3A7 (K(i) 2.1 microM and 10.6 microM, respectively). In conclusion, significant differences exist in the inhibitory potency of protease inhibitors for different CYP3A forms. Ritonavir, nelfinavir, saquinavir and amprenavir seem to be prone to drug-drug interactions by inhibiting both CYP3A4 and CYP3A5. Especially nelfinavir and ritonavir also have a potential to inhibit foetal CYP3A7-mediated drug metabolism and some endogenous pathways that may be crucial to normal foetal development, while indinavir has the lowest potential to inhibit CYP3A5 and CYP3A7.

Topics: Aryl Hydrocarbon Hydroxylases; Carbamates; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Dose-Response Relationship, Drug; Drug Interactions; Furans; HIV Protease Inhibitors; Humans; Hydroxylation; In Vitro Techniques; Indinavir; Isoenzymes; Kinetics; Nelfinavir; Recombinant Proteins; Ritonavir; Saquinavir; Sulfonamides; Testosterone

Mutation proI47A has recently been associated with lopinavir/ritonavir (LPV/r) resistance. Only four out of 1859 specimens (0.2%) sent for drug resistance testing (219 drug-naive and 1650 antiretroviral-experienced) showed I47A. All belonged to patients failing LPV/r. The prevalence among protease inhibitor-experienced patients was 0.6%. Phenotypic testing showed that proI47A caused high-level lopinavir resistance (> 100-fold) and cross-resistance to amprenavir, whereas it caused hypersusceptibility to saquinavir. ProI47A should thus be considered the primary lopinavir resistance mutation.

Topics: Carbamates; Codon; Drug Resistance, Viral; Furans; Genotype; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Lopinavir; Mutation; Nelfinavir; Phenotype; Pyrimidinones; Ritonavir; Saquinavir; Sulfonamides

To evaluate the drug interaction between fosamprenavir (FPV) and esomeprazole (ESO) after repeated doses in healthy adults.. Subjects received ESO 20 mg once daily (qd) for 7 days followed by either ESO 20 mg qd + FPV 1400 mg twice daily (bid) or ESO 20 mg qd + FPV 700 mg bid + ritonavir (RTV) 100 mg bid for 14 days in arms 1 and 2, respectively. After a 21- to 28-day washout, subjects received either FPV 1400 mg bid for 14 days (arm 1) or FPV 700 mg bid + RTV 100 mg bid for 14 days (arm 2). Pharmacokinetic sampling was conducted on the last day of each treatment.. Simultaneous coadministration of ESO 20 mg qd with either FPV 1400 mg bid or FPV 700 mg bid + RTV 100 mg bid had no effect on steady-state amprenavir pharmacokinetics. The only effect on plasma ESO exposure was a 55% increase in area under the plasma concentration-time curve during a dosing interval, tau[AUC0-tau], after coadministration of ESO 20 mg qd with FPV 1400 mg bid.. FPV 1400 mg bid or FPV 700 mg bid + RTV 100 mg bid may be coadministered simultaneously with ESO without dose adjustment. However, the impact of staggered administration of proton pump inhibitors (PPI) on plasma amprenavir exposure is unknown at present.

Topics: Administration, Oral; Adolescent; Adult; Carbamates; Diarrhea; Drug Administration Schedule; Drug Combinations; Esomeprazole; Female; Furans; Headache; Humans; Male; Middle Aged; Nausea; Organophosphates; Ritonavir; Sulfonamides

To investigate the effects of various HIV protease inhibitors on the function of pancreatic beta-cells.. Rat insulinoma INS-1 cells were incubated with different concentrations of ritonavir or amprenavir for 48 h and stimulated with 20 mmol/L D-glucose for 30 min. The rate of insulin release was measured in the supernatant by ELISA, normalized to cellular DNA contents. Cells were counted with trypan blue and MTT test were determined to evaluate the effect of protease inhibitors on cell viability.. Ritonavir treatment significantly decreased baseline insulin release and glucose-stimulated insulin release in a dose-dependent manner (r=-0.861, -0.839, both P<0.01). For 10 micromol/L of ritonavir, the decrease rate of baseline insulin secretion and glucose-stimulated insulin secretion was 46% and 47%, respectively. Amprenavir had no effect on the rate of insulin release.. Various HIV protease inhibitors present different effect on the insulin release of pancreatic beta-cells.

Topics: Animals; Carbamates; Furans; HIV Protease Inhibitors; Insulin; Insulin Secretion; Insulinoma; Islets of Langerhans; Pancreatic Neoplasms; Rats; Ritonavir; Sulfonamides

Cross-contamination among wells of a high-throughput, high-density assay is a risk that cannot be detected or controlled by the performance of calibration standards and quality control samples. In the current practice, carryover and cross-contamination is detected only when analytes are detected in blank, zero, placebo, pre-dose samples, in a low standard or low quality control sample. There is no mechanism that allows bioanalytical scientists to determine if cross-contamination has occurred among other samples. As a result, erroneous results can be released to clients even though a batch meets the acceptance criteria. We tested a new approach that quantifies the cross-contamination of each sample and allows the scientist to make quality decisions with documentation. The approach will also detect carryover in over 90% of the wells. Briefly, two additional analytes were added as contamination markers. The markers were added to a multi-well plate alternatively creating a pattern of a checkerboard. The spiked multi-well plate was then used to perform the assay. If both markers were detected in a well, the sample was considered contaminated. The amount of the unexpected marker detected in a well measures the degree of contamination and may be used to make deactivation decisions. Depending on the relative impact of the contamination, a scientist can choose to tolerate the bias, reject the sample, reject the batch or raise the lower limit of quantitation for the batch. A guideline for rejection decisions is presented for discussion.

Topics: Biomarkers; Carbamates; Chemistry Techniques, Analytical; Chromatography, High Pressure Liquid; Drug Contamination; Furans; Humans; Lopinavir; Pyrimidinones; Quality Control; Reproducibility of Results; Ritonavir; Saquinavir; Sensitivity and Specificity; Sulfonamides; Tandem Mass Spectrometry

The need for a potent HIV protease inhibitor (PI) to combat emerging PI-resistant viruses is anticipated. Analogs formulated from the combination of structural fragments of Ritonavir, Lopinavir, and Amprenavir were synthesized. Analogs containing the oxime pharmacophore were found to have improved activities against both wild type and resistant (A17) viruses. The synthesis and structure-activity relationships (SAR) based upon the in vitro IC50 of this series of compounds are reported.

Topics: Binding Sites; Carbamates; Drug Design; Furans; HIV Protease; HIV Protease Inhibitors; Kinetics; Lopinavir; Models, Molecular; Molecular Conformation; Pyrimidinones; Ritonavir; Sulfonamides

Several studies suggest that therapeutic drug monitoring of protease inhibitors and nonnucleoside reverse transcriptase inhibitors may contribute to the clinical outcome of HIV-infected patients. Because of the growing number of antiretroviral drugs and of drug combinations than can be administered to these patients, an accurate high-performance liquid chromatographic (HPLC) method allowing the simultaneous determination of these drugs may be useful. To date, the authors present the first simultaneous HPLC determination of the new protease inhibitor atazanavir with all the others currently in use (M8 nelfinavir metabolite included) and the 2 widely used nonnucleoside reverse transcriptase inhibitors efavirenz and nevirapine. This simple HPLC method allows the analysis all these drugs at a single ultraviolet wavelength following a 1-step liquid-liquid extraction procedure. A 500-muL plasma sample was spiked with internal standard and subjected to liquid-liquid extraction using by diethyl ether at pH 10. HPLC was performed using a Symmetry Shield RP18 and gradient elution. All the drugs of interest and internal standard were detected with ultraviolet detection at 210 nm. Calibration curves were linear in the range 50-10,000 ng/mL. The observed concentrations of the quality controls at plasma concentrations ranging from 50 to 5000 ng/mL for these drugs showed that the overall accuracy varied from 92% to 104% and 92% to 106% for intraday and day-to-day analysis, respectively. No metabolites of the assayed compounds or other drugs commonly coadministered to HIV-positive patients were found to coelute with the drugs of interest or with the internal standard. This assay was developed for the purpose of therapeutic monitoring (TDM) in HIV-infected patients.

Topics: Alkynes; Atazanavir Sulfate; Benzoxazines; Calibration; Carbamates; Chromatography, Liquid; Cyclopropanes; Drug Stability; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Nelfinavir; Nevirapine; Oligopeptides; Oxazines; Pyridines; Pyrimidinones; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Specimen Handling; Spectrophotometry, Ultraviolet; Sulfonamides

Intensification therapy adding a boosted protease inhibitor (PI) to a failing regimen has the potential to worsen the resistance profile. Sixty-six patients included in four different boosted PI intensification studies were assessed and resistance mutations in the reverse transcriptase and protease genes were evaluated at baseline and 4 weeks after the initiation of the intensification strategy. Only one of the 66 patients developed changes in their pattern of mutations able to generate or increase resistance to new drugs.

Topics: Antiretroviral Therapy, Highly Active; Carbamates; Drug Resistance, Multiple, Viral; Follow-Up Studies; Furans; HIV Infections; HIV Protease; HIV Protease Inhibitors; HIV Reverse Transcriptase; HIV-1; Humans; Indinavir; Lopinavir; Mutation; Pyrimidinones; Ritonavir; Saquinavir; Sulfonamides; Treatment Failure; Viral Load

We report a case of small cell lung cancer in a patient with human immunodeficiency virus (HIV) infection. The patient was a 51-year-old man diagnosed 8 years previously as seropositive for HIV, who was admitted to our hospital for re-evaluation of antiretroviral medications due to multidrug resistance. Chest radiograph revealed an abnormal hilar shadow subsequently confirmed to be small cell lung cancer. He received chemotherapy concurrently with highly active antiretroviral therapy (HAART), and lived for 14 months after the diagnosis. The prognosis of lung cancer in HIV-seropositive patients is very poor, and adverse effects of chemotherapy occur more frequently than in other patients. However, the simultaneous antiretroviral agents and combination chemotherapy was successful. Such treatment may be effective despite an otherwise poor prognosis, including HIV infection.

Topics: Alkynes; Anti-HIV Agents; Antineoplastic Combined Chemotherapy Protocols; Antiretroviral Therapy, Highly Active; Benzoxazines; Camptothecin; Carbamates; Carboplatin; Carcinoma, Small Cell; Cisplatin; Cyclopropanes; Didanosine; Dideoxynucleosides; Drug Administration Schedule; Furans; HIV Infections; HIV Long-Term Survivors; Humans; Irinotecan; Lung Neoplasms; Male; Middle Aged; Oxazines; Ritonavir; Sulfonamides; Tomography, X-Ray Computed

HIV protease inhibitors (PIs) have been implicated to cause cardiovascular complications. Previous studies demonstrated that the PI ritonavir (RTV) caused endothelial dysfunction in porcine arteries. This study investigated and compared the effects of 5 commonly used PIs on vasomotor function, endothelial nitric oxide synthase (eNOS) expression, and oxidative stress in porcine coronary arteries. Vessel rings were incubated with 15 microM of RTV, amprenavir (APV), saquinavir (SQV), indinavir (IDV), or nelfinavir (NFV) for 24 hours. Vasomotor function was studied using a myograph system. The contractility of the rings was significantly reduced for RTV and SQV. In response to bradykinin at 10(-5) M, the endothelium-dependent relaxation was significantly reduced for RTV, APV, and SQV. The eNOS mRNA levels were significantly reduced for RTV, APV, and SQV. Furthermore, the superoxide anion (O(2)(-)) levels of the vessels were significantly increased for RTV and APV. It was found that nitric oxide production was decreased, whereas the level of nitrotyrosine proteins was increased in RTV-treated vessels. Furthermore, antioxidant seleno-L-methionine (SeMet) reversed RTV-induced O(2)(-) production and vasomotor dysfunction. Thus, the HIV PIs RTV, APV, and SQV at 15 microM have more potent in vitro effects on vasomotor dysfunction, eNOS downregulation, and O(2)(-) production than IDV and NFV. The antioxidant SeMet can block these adverse effects of RTV. The results suggest that antioxidant therapy may have applications for controlling PI-associated cardiovascular complications.

Topics: Animals; Bradykinin; Carbamates; Coronary Vessels; Down-Regulation; Furans; HIV Protease Inhibitors; Indinavir; Methionine; Muscle Contraction; Muscle, Smooth, Vascular; Myography; Nelfinavir; Nitric Oxide Synthase; Organ Culture Techniques; Ritonavir; RNA, Messenger; Saquinavir; Selenium Compounds; Sulfonamides; Superoxides; Swine; Vasomotor System

The clinical use of HIV protease inhibitors (PIs) is associated with the development of peripheral insulin resistance. The incidence and degree of impaired glucose tolerance observed in treated patients vary considerably between drugs, however. To compare the ability of HIV PIs to alter peripheral glucose disposal acutely in a genetically identical model system at therapeutically relevant drug levels, healthy lean male rats previously naive to PI exposure were given ritonavir, amprenavir, lopinavir/ritonavir (4:1), or atazanavir by continuous intravenous infusion to achieve steady state drug levels of 10 or 25 muM rapidly. Under euglycemic hyperinsulinemic clamp conditions, a dose-dependent reduction in the peripheral glucose disposal rate (Rd) was observed with all the PIs except atazanavir. The rank order of sensitivity was ritonavir, lopinavir, and then amprenavir. Changes in skeletal muscle and heart 2-deoxyglucose (2-DOG) uptake correlated with reductions in Rd. All 3 of these PIs also produced significant reductions in 2-DOG uptake into primary rat adipocytes in vitro. Atazanavir had no effect on glucose uptake in vitro or in vivo. The in vivo potency of PIs to impair peripheral glucose disposal acutely correlates with the degree of insulin resistance observed in HIV-infected patients receiving these drugs. Preclinical testing of novel candidate PIs in a rodent model system may be useful in identifying the future risk of altering glucose homeostasis.

Topics: Adipocytes; Animals; Atazanavir Sulfate; Carbamates; Deoxyglucose; Dose-Response Relationship, Drug; Furans; Glucose; Glucose Clamp Technique; HIV Protease Inhibitors; Infusions, Intravenous; Insulin Resistance; Lopinavir; Male; Models, Animal; Muscle, Skeletal; Myocardium; Oligopeptides; Pyridines; Pyrimidinones; Rats; Ritonavir; Sulfonamides

Genotypes in nine highly protease inhibitor (PI)-experienced patients were studied before and after lopinavir/ritonavir (LPV/r) treatment. Resistance to amprenavir was the rule both before and after LPV/r treatment. Treatment with LPV/r can select for the 50 V mutation. In this setting, significant differences in the inference of the amprenavir phenotype from genotype were observed when using different algorithms.

Topics: Adult; Anti-Retroviral Agents; Carbamates; CD4 Lymphocyte Count; Drug Resistance, Viral; Drug Therapy, Combination; Female; Furans; Genotype; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Male; Middle Aged; Mutation; Pyrimidinones; Retrospective Studies; Ritonavir; RNA, Viral; Sulfonamides

Amprenavir (APV) is an HIV protease inhibitor (PI) used for the treatment of either naive or PI-experienced HIV-infected patients. Several genotypic resistance pathways in protease gene have been described to be associated to unboosted APV failure (I50V, V32I + I47V, I54L/M, or less commonly I84V, which may be accompanied by one ore more accessory mutations such as L10F, L33F, M46I/L). The aims of this study were to investigate the efficacy up to week 24 of an APV plus ritonavir containing regimen in PI experienced patients and to determine the genotypic resistance profiles emerging in patients failing to this therapy. Forty-nine, PI experienced but APV naïve patients were treated with APV (600 mg bid) plus ritonavir (100 mg bid). By intent-to-treat analysis, the median decrease in viral load (VL) was -1.32 log10 (min +0.6; max -2.8) and -1.46 log10 (min +0.5; max -2.8) 12 and 24 weeks after initiating APV plus ritonavir regimen, respectively. Twelve patients harboured a VL >200 copies/ml at week 24. Among these patients, the selection of mutations previously described with the use of APV as first PI (V32I, L33F, M46I/L, I50V, 54M/L, and I84V) was observed. However, in some cases, mutations classically described after the use of other PIs (V82F and L90M) were selected but always with APV-specific mutations. There was no relation between the resistance pathways selected with either APV or ritonavir plasma minimal concentration, but higher APV plasma minimal concentration were associated with a lower rate of resistance mutations selection.

Topics: Adult; Amino Acid Substitution; Carbamates; Drug Resistance, Viral; Drug Therapy, Combination; Female; Furans; HIV; HIV Infections; HIV Protease; HIV Protease Inhibitors; Humans; Male; Middle Aged; Mutation, Missense; Ritonavir; Selection, Genetic; Sulfonamides; Treatment Failure; Viral Load; Viremia

The purpose of this study was to investigate placental transfer and amniotic fluid concentrations of protease inhibitors when they are given to pregnant women who are infected with human immunodeficiency virus.. Fifty-eight mothers who received antiretroviral therapy that included > or =1 protease inhibitors for clinical indications at the time of delivery were enrolled in the study. Maternal blood samples and amniotic fluid were obtained during delivery or cesarean delivery, and paired cord blood samples were obtained by venipuncture immediately after the delivery. Drug concentrations were measured with high performance liquid chromatography.. Most maternal protease inhibitor plasma concentrations (38/66 concentrations) were below the trough concentrations that are recommended for therapeutic drug monitoring. Cord blood concentrations were below the assay limit of detection in 10 of 40 samples for nelfinavir and 25 of 40 samples for its metabolite M8, 9 of 11 samples for ritonavir, 4 of 6 samples for indinavir, 5 of 6 samples for saquinavir but were detectable in 3 of 3 samples for amprenavir. Among the 24 amniotic fluid samples that were available, the concentrations below the detection limit were 10 of 16 samples for nelfinavir, 11 of 16 samples for M8, 1 of 3 samples for indinavir, 4 of 4 samples for ritonavir, and 0 of 1 samples for amprenavir. There were significant correlations between cord blood and maternal concentrations of nelfinavir and its metabolite M8.. Placental transfer of the human immunodeficiency virus protease inhibitors is generally low; however, it may differ greatly according to the molecule.

Topics: Adult; Amniotic Fluid; Carbamates; Drug Therapy, Combination; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Maternal-Fetal Exchange; Nelfinavir; Pregnancy; Pregnancy Complications, Infectious; Ritonavir; Saquinavir; Sulfonamides

To determine the safety and effectiveness of a once-daily highly active antiretroviral therapy (HAART) regimen in patients at risk for poor adherence using directly observed therapy (DOT) for 24 weeks followed by weekly phone contact for another 24 weeks.. A prospective, open-label pilot study was carried out. Antiretroviral-naïve patients with advanced HIV disease were treated with once-daily amprenavir 1200 mg, ritonavir 200 mg, didanosine 400 mg and lamivudine 300 mg. After 24 weeks, DOT was substituted by weekly phone contact. Measurements of viral load and CD4 cell count, and safety laboratory measurements, were taken regularly for 48 weeks.. Twenty-two patients were enrolled in the study, of whom 19 completed at least 4 weeks of treatment. Seventeen patients completed 24 weeks and 13 completed 48 weeks. None discontinued treatment as a result of adverse events. The median baseline HIV viral load was 5.29 log(10) HIV-1 RNA copies/mL and the median CD4 cell count was 20 cells/microL. At weeks 24 and 48, 74% of the patients had viral loads <400 copies/mL. At 48 weeks, the median decrease in viral load from baseline was 3.06 log(10) copies/mL, and the median increase in CD4 cell count was 118 cells/microL. The median trough plasma amprenavir concentrations at weeks 1 and 24 were 1.87 and 1.42 microg/mL, respectively.. This study suggests that DOT followed by weekly patient contact results in good treatment outcome in this challenging population. The median trough plasma amprenavir concentrations were above the effective concentration of drug that resulted in 90% inhibition of viral load in vivo (EC(90)) for wild-type HIV.

Topics: Adult; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Carbamates; Directly Observed Therapy; Drug Administration Schedule; Female; Furans; HIV Infections; Humans; Male; Middle Aged; Pilot Projects; Ritonavir; Statistics, Nonparametric; Sulfonamides; Treatment Outcome; Viral Load

The mechanism by which chronic treatment with HIV (human immunodeficiency virus)-1 protease inhibitors leads to a deterioration of glucose metabolism appears to involve insulin resistance, and may also involve impaired insulin secretion. Here we investigated the long-term effects of HIV-1 protease inhibitors on glucose-stimulated insulin secretion from beta cells and explored whether altered insulin secretion might be related to altered insulin signaling. INS-1 cells were incubated for 48 h with different concentrations of amprenavir, indinavir, nelfinavir, ritonavir or saquinavir, stimulated with 20 mM d-glucose, and insulin determined in the supernatant. To evaluate insulin signaling, cells were stimulated with 100 nM insulin for 2 min, and insulin-receptor substrate (IRS)-1, -2 and Akt phosphorylation determined. Incubation for 48 h with ritonavir, nelfinavir and saquinavir resulted in impaired glucose-induced insulin secretion at 2.5, 5 and 5 microM respectively, whereas amprenavir or indinavir had no effects even at 20 and 100 microM respectively. The impaired insulin secretion by ritonavir, nelfinavir and saquinavir was associated with decreased insulin-stimulated IRS-2 phosphorylation, and, for nelfinavir and saquinavir, with decreased insulin-stimulated IRS-1 and Thr308-Akt phosphorylation. No such effects on signaling were observed with amprenavir or indinavir. In conclusion, certain HIV-1 protease inhibitors, such as ritonavir, nelfinavir and saquinavir, not only induce peripheral insulin resistance, but also impair glucose-stimulated insulin secretion from beta cells. With respect to the long-term effect on beta-cell function there appear to be differences between the protease inhibitors that may be clinically relevant. Finally, these effects on insulin secretion after a 48 h incubation with protease inhibitor were associated with a reduction of the insulin-stimulated phosphorylation of insulin signaling parameters, particularly IRS-2, suggesting that protease inhibitor-induced alterations in the insulin signaling pathway may contribute to the impaired beta-cell function.

Topics: Carbamates; Cell Line; Furans; Glucose; HIV Protease Inhibitors; Humans; Indinavir; Insulin; Insulin Receptor Substrate Proteins; Insulin Secretion; Intracellular Signaling Peptides and Proteins; Islets of Langerhans; Nelfinavir; Phosphoproteins; Phosphorylation; Ritonavir; Saquinavir; Signal Transduction; Stimulation, Chemical; Sulfonamides; Time Factors

The increasing interest in applying therapeutic drug monitoring (TDM) to antiretroviral therapy is related to the observed interindividual variation in antiretroviral pharmacokinetics that results in a wide range of drug exposure from fixed-dosing regimens and the rapid evolution in the availability of phenotypic assays that generate a target 50% inhibitory concentration (e.g., IC(50)) as a basis for adjusting individual antiretroviral dosages. To facilitate the application of TDM, a method for the simultaneous determination of eight species has been developed. This method is used to quantitate efavirenz and the following protease inhibitors: amprenavir, indinavir, lopinavir, nelfinavir and its active metabolite (M8), ritonavir, and saquinavir. The method using reversed-phase high-performance liquid chromatography (RP-HPLC) was validated. Detection is effected using a photodiode-array detector (PDA) scanning at four different wavelengths. This method allows for detection of all analytes to a lower limit of quantitation of 0.1 to 0.2 microg/mL with an interday variation in CV ranging from 3.5% to 10.4%. The method is being applied to a TDM program that is currently being implemented in the authors' laboratory.

Topics: Alkynes; Anti-HIV Agents; Benzoxazines; Carbamates; Chromatography, High Pressure Liquid; Cyclopropanes; Furans; Heparin; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Nelfinavir; Oxazines; Pyrimidinones; Ritonavir; Saquinavir; Sulfonamides

HIV protease inhibitors (PIs) acutely and reversibly inhibit the insulin-responsive glucose transporter Glut 4, leading to peripheral insulin resistance and impaired glucose tolerance. Minimal modeling analysis of glucose tolerance tests on PI-treated patients has revealed an impaired insulin secretory response, suggesting additional pancreatic beta-cell dysfunction. To determine whether beta-cell function is acutely affected by PIs, we assayed glucose-stimulated insulin secretion in rodent islets and the insulinoma cell line MIN6. Insulin release from MIN6 cells and rodent islets was significantly inhibited by the PI indinavir with IC(50) values of 1.1 and 2.1 micro mol/l, respectively. The uptake of 2-deoxyglucose in MIN6 cells was similarly inhibited (IC(50) of 2.0 micro mol/l), whereas glucokinase activity was unaffected at drug levels as high as 1 mmol/l. Glucose utilization was also impaired at comparable drug levels. Insulin secretogogues acting downstream of glucose transport mostly reversed the indinavir-mediated inhibition of insulin release in MIN6 cells. Intravenous infusion of indinavir during hyperglycemic clamps on rats significantly suppressed the first-phase insulin response. These data suggest that therapeutic levels of PIs are sufficient to impair glucose sensing by beta-cells. Thus, together with peripheral insulin resistance, beta-cell dysfunction likely contributes to altered glucose homeostasis associated with highly active antiretroviral therapy.

Topics: Animals; Carbamates; Cells, Cultured; Furans; Glucose; HIV Protease Inhibitors; Indinavir; Insulin; Insulin Secretion; Islets of Langerhans; Kinetics; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Nelfinavir; Ritonavir; Sulfonamides

The objective of this study was to investigate the long-term effects of anti-retroviral protease inhibitors (PIs) on 2-deoxy-d -glucose (2-DG) transport in L6 cells in vitro. Exposure of L6 cells to saquinavir, ritonavir, indinavir and amprenavir resulted in significant increases in 2-DG transport using PI concentrations of 1-10 microM with continual exposure to PI. After removal of the PI for up to 48 h, 2-DG transport increases did not change and remained at pre-reversal levels. These changes in 2-DG transport were not related to stress-induced sugar transport or to apoptosis. The examination of glucose transporter (GLUT) 1, 3 or 4 translocation with subcellular fractionation indicated that insulin (i.e. 67 nM) could induce the translocation of all the GLUTs to the plasma membrane. Also, ritonavir (10 microM), which leads to a 2-fold increase in 2-DG transport, demonstrated increased GLUT (i.e. 1, 3 or 4) presence in the plasma membrane fraction, in the presence or absence of insulin. This increased 2-DG transport involved transporter presence in plasma membrane preparations and did not affect the ability of insulin to stimulate 2-DG transport with continual PI exposure. The mechanism(s) involved indicates ready reversibility of PI effects on transporters. The mechanism(s) why reversibility of PI-induced 2-DG transport was similar plus or minus PI was not apparent.

Topics: Biological Transport; Blotting, Western; Carbamates; Cell Membrane; Cells, Cultured; Deoxyglucose; Furans; Glucose Transporter Type 1; Glucose Transporter Type 3; Glucose Transporter Type 4; HIV Protease Inhibitors; Humans; Indinavir; Insulin; Monosaccharide Transport Proteins; Muscle Proteins; Myoblasts; Nerve Tissue Proteins; Ritonavir; Saquinavir; Sulfonamides

Lipodystrophy is a major side effect of HIV protease inhibitor (PI) antiretroviral therapy. It has been shown that protease inhibitors interfere in vitro with adipocyte differentiation. However, there is no evidence that PIs accumulate into preadipocytes and adipocytes and that intra-cellular accumulation is sufficient to alter differentiation. We assessed the effect of six different PIs on the differentiation of cells from four clonal lines. We also studied the capacity of ritonavir to accumulate both into drug-sensitive and drug-resistant cultured adipocytes.. Adipocyte differentiation of mouse 3T3-F442A, 3T3-L1 and Ob1771 cells as well as embryonic stem cells were investigated at pharmacological concentrations of indinavir, saquinavir, ritonavir, amprenavir, nelfinavir and lopinavir. We used a sensitive ELISA to determine intracellular concentration of ritonavir from 3T3-L1 and Ob1771 preadipocytes.. Nelfinavir and lopinavir inhibited adipocyte differentiation whereas amprenavir was ineffective. Indinavir, saquinavir and ritonavir inhibited differentiation of 3T3-L1 and 3T3-F442A cells but did not alter differentiation of either Ob1771 or embryonic stem cells. We showed that ritonavir accumulated in preadipocytes and fully differentiated 3T3-L1 adipocytes as a function of its extracellular concentration. Although Ob1771 cells were resistant and 3T3-L1 cells were sensitive to ritonavir, the drug accumulated to similar levels in both cases.. Protease inhibitors inhibit adipocyte differentiation depending on the cell model used. We showed for the first time that ritonavir accumulates into preadipocytes and adipocytes, suggesting a direct effect on intracellular targets. However, intracellular accumulation was clearly not sufficient as Ob1771 cells remained resistant to the inhibitory effect of ritonavir.

Topics: 3T3 Cells; Adipocytes; Animals; Carbamates; Cell Differentiation; Cell Line; Enzyme-Linked Immunosorbent Assay; Furans; HIV Protease Inhibitors; Indinavir; Lopinavir; Mice; Mice, Inbred Strains; Nelfinavir; Pyrimidinones; Ritonavir; Saquinavir; Sulfonamides

We compared seminal plasma pharmacokinetic data for the investigational amprenavir prodrug GW433908 with those for amprenavir and an amprenavir-ritonavir combination regimen. All 3 regimens resulted in detectable blood plasma and seminal plasma concentrations of amprenavir. The majority of these concentrations were greater than the plasma protein-corrected 50% inhibitory concentration for wild-type human immunodeficiency virus type 1.

Topics: Adult; Anti-HIV Agents; Carbamates; Chemistry, Pharmaceutical; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Male; Organophosphates; Prodrugs; Ritonavir; Semen; Sulfonamides

A sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS-MS) method has been developed to measure the levels of five HIV protease inhibitors nelfinavir (NFV), indinavir (IDV), ritonavir (RTV), saquinavir (SQV) and amprenavir (APV) in human plasma. The analytes and internal standard are isolated from plasma by a simple acetonitrile precipitation of plasma proteins followed by centrifugation. LC-MS-MS in positive mode used pairs of ions at m/z of 568.4/330.0, 614.3/421.2, 720.9/296.0, 671.1/570.2 and 505.9/245.0 for NFV, IDV, RTV, SQV and APV, respectively and 628/421 for the internal standard. Two 1/x weighted linear calibration curves for each analyte were established for quantitation with the low curve ranging from 5 to 1000 ng/ml and while the high curve ranging from 1000 to 10,000 ng/ml. Mean inter- and intra-assay coefficients of variation (CVs) over the ranges of the standard curves were less than 10%. The overall recovery of NFV, IDV, RTV, SQV and APV were 88.4, 91.4, 92.2, 88.9 and 87.6%, respectively.

Topics: Carbamates; Chromatography, Liquid; Furans; Gas Chromatography-Mass Spectrometry; HIV Protease Inhibitors; Indinavir; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides

The efficacy of an amprenavir (APV)-containing therapy without (group A) or with (group B) ritonavir was assessed in patients with failure of previous protease inhibitor therapy for human immunodeficiency virus (HIV) infection. The mean minimal plasma APV concentrations in groups A and B were 58 and 1,320 ng/ml, respectively, corresponding to APV inhibitory quotients of 0.2 (range, 0.03 to 0.70) and 7.0 (range, 1.4 to 145), respectively. At week 24, 2 of 8 and 13 of 14 patients in groups A and B, respectively, had <200 HIV RNA copies/ml of plasma, including 4 of 5 patients infected with APV-resistant viruses.

Topics: Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Carbamates; Drug Therapy, Combination; Furans; HIV; HIV Infections; Humans; Ritonavir; RNA, Viral; Sulfonamides

Topics: Carbamates; Drug Synergism; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Male; Pilot Projects; Pyrimidinones; Ritonavir; Sulfonamides

Topics: Anti-HIV Agents; Blood; Carbamates; Cerebrospinal Fluid; Drug Resistance, Viral; Drug Therapy, Combination; Female; Furans; Genitalia; Genotype; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Male; Mutation; Phenotype; Randomized Controlled Trials as Topic; Retrospective Studies; Ritonavir; Sulfonamides; Time Factors; Viral Load

A sensitive and selective liquid chromatographic assay has been developed for the determination of the six currently protease inhibitors approved by the U.S. Food & Drug Administration (amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, and saquinavir) plus the M8 active metabolite of nelfinavir and the nonnucleoside reverse transcription inhibitor efavirenz in a single run. Pretreatment of 1-mL plasma sample spiked with internal standard was made by a solid-phase extraction procedure using a polymeric reversed-phase sorbent. Liquid chromatography was performed using a narrow-bore C18 reversed-phase column and gradient elution. Double ultraviolet detection at 265 nm (amprenavir) and at 210 nm (all other assayed drugs and internal standard) was used. Calibration curves were linear in the range 25 to 10,000 ng/mL, and the assay has been validated over the range 25 to 5,000 ng/mL. Average accuracies at four concentrations were in the range 92.4% to 103.0% and 94.4% to 103.0% for within-day and between-day, respectively, and the coefficients of variation were less than 8%. Mean absolute recoveries varied from 72.8% (ritonavir) to 93.7% (indinavir). No metabolite of the protease inhibitors was found to coelute with the drugs of interest or with the internal standard. At this time, among the tested drugs, especially all the currently licensed nucleosides and the other nonnucleoside reverse transcription inhibitor nevirapine that can be used in combination with the protease inhibitors, none was found to interfere with the assay.

Topics: Alkynes; Benzoxazines; Carbamates; Chromatography, Liquid; Cyclopropanes; Drug Monitoring; Furans; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Nelfinavir; Oxazines; Pyrimidinones; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sulfonamides

Human immunodeficiency virus (HIV) therapies have been associated with alterations in fat metabolism and bone mineral density. This study examined the effects of HIV protease inhibitors (PIs) on bone resorption, bone formation, and adipocyte differentiation using ex vivo cultured osteoclasts, osteoblasts, and adipocytes, respectively. Osteoclast activity, measured using a rat neonatal calvaria assay, increased in the presence of nelfinavir (NFV; 47.2%, p = 0.001), indinavir (34.6%, p = 0.001), saquinavir (24.3%, p = 0.001), or ritonavir (18%, p < 0.01). In contrast, lopinavir (LPV) and amprenavir did not increase osteoclast activity. In human mesenchymal stem cells (hMSCs), the PIs LPV and NFV decreased osteoblast alkaline phosphatase enzyme activity and gene expression significantly (p < 0.05). LPV and NFV diminished calcium deposition and osteoprotegrin expression (p < 0.05), whereas the other PIs investigated did not. Adipogenesis of hMSCs was strongly inhibited by saquinavir and NFV (>50%, p < 0.001) and moderately inhibited by ritonavir and LPV (>40%, p < 0.01). Expression of diacylglycerol transferase, a marker of adipocyte differentiation, decreased in hMSCs treated with NFV. Amprenavir and indinavir did not affect adipogenesis or lipolysis. These results suggest that bone and fat formation in hMSCs of bone marrow may be coordinately down-regulated by some but not all PIs.

Topics: Adipocytes; Animals; Animals, Newborn; Bone and Bones; Calcium; Carbamates; Cells, Cultured; Down-Regulation; Fats; Furans; Glycoproteins; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Mesoderm; Nelfinavir; Osteoblasts; Osteoclasts; Osteoprotegerin; Pyrimidinones; Rats; Rats, Wistar; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Ritonavir; Saquinavir; Skull; Stem Cells; Sulfonamides

Topics: Carbamates; Dose-Response Relationship, Drug; Drug Interactions; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Pyrimidinones; Ritonavir; Salvage Therapy; Sulfonamides

Topics: Carbamates; Drug Evaluation; Furans; HIV Protease Inhibitors; Humans; Indinavir; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides

Topics: Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Carbamates; Delavirdine; Drug Synergism; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Pyrimidinones; Reverse Transcriptase Inhibitors; Ritonavir; Sulfonamides

Topics: Carbamates; Drug Approval; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Ritonavir; Sulfonamides; United States; United States Food and Drug Administration

Topics: Carbamates; Drug Administration Schedule; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Ritonavir; Sulfonamides

A selective and sensitive high-performance liquid chromatographic (HPLC) method has been developed for the determination of the six human immunodeficiency virus (HIV)-protease inhibitors (amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, and saquinavir) and the non-nucleoside reverse transcriptase inhibitors (efavirenz and nevirapine) in a single run. After a liquid-liquid extraction with diethyl ether, the six protease inhibitors and the two non-nucleoside reverse transcriptase inhibitors are separated on a Stability RP18 column eluted with a gradient of acetonitrile and phosphate buffer 50 mmol/L pH 5.65. A sequential ultraviolet detection (5-minute sequence set at 240 nm for nevirapine acquisition, 22-minute sequence set at 215 nm for other antiretroviral drugs acquisition followed by a sequence set at 260 nm for internal standard acquisition) allowed for simultaneous quantitation of the six protease inhibitors, nevirapine, and efavirenz. Calibration curves were linear in the range 100 ng/mL to 10,000 ng/mL. The limit of quantitation was 50 ng/mL for all drugs except nevirapine (100 ng/mL). Average accuracy at four concentrations ranged from 88.2% to 110.9%. Both interday and intraday coefficients of variation were less than 11% for all drugs. The extraction recoveries were greater than 62%. This method is simple and shows a good specificity with respect to commonly co-prescribed drugs. This method allows accurate therapeutic monitoring of amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, efavirenz, and nevirapine.

Topics: Alkynes; Benzoxazines; Carbamates; Chromatography, High Pressure Liquid; Cyclopropanes; Drug Monitoring; Furans; HIV Infections; Humans; Indinavir; Lopinavir; Nelfinavir; Nevirapine; Oxazines; Protease Inhibitors; Pyrimidinones; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sulfonamides

To investigate the involvement of P-glycoprotein (Pgp) and the multidrug resistance-associated protein (MRP) on the active transport of the HIV protease inhibitors amprenavir, ritonavir and indinavir.. The transport behaviour of ritonavir, indinavir and amprenavir in the presence and absence of Pgp modulators and probenecid was investigated in an in vitro blood--brain barrier (BBB) co-culture model and in monolayers of LLC-PK1, LLC-PK1:MDR1, LLC-PK1:MRP1 and Caco-2 cells.. All three HIV protease inhibitors showed polarized transport in the BBB model, LLC-PK1:MDR1 and Caco-2 cell line. The Pgp modulators SDZ-PSC 833, verapamil and LY 335979 inhibited polarized transport, although their potency was dependent on both the cell model and the HIV protease inhibitor used. Ritonavir and indinavir also showed polarized transport in the LLC-PK1 and LLC-PK1:MRP1 cell line, which could be inhibited by probenecid. HIV protease inhibitors were not able to inhibit competitively polarized transport of other HIV protease inhibitors in the LLC-PK1:MDR1 cell line.. Amprenavir, ritonavir and indinavir are mainly actively transported by Pgp, while MRP also plays a role in the transport of ritonavir and indinavir. This indicates that inhibition of Pgp could be useful therapeutically to increase HIV protease inhibitor concentrations in the brain and in other tissues and cells expressing Pgp. The HIV protease inhibitors were not able to inhibit Pgp-mediated efflux when given simultaneously, suggesting that simultaneous administration of these drugs will not increase the concentration of antiretroviral drugs in the brain.

Topics: Animals; Astrocytes; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP-Binding Cassette Transporters; Biological Transport, Active; Blood-Brain Barrier; Caco-2 Cells; Carbamates; Cattle; Cell Line, Transformed; Cells, Cultured; Coculture Techniques; Cyclosporins; Dibenzocycloheptenes; Endothelium, Vascular; Furans; HIV Protease Inhibitors; Humans; Indinavir; LLC-PK1 Cells; Multidrug Resistance-Associated Proteins; Probenecid; Quinolines; Rats; Rats, Wistar; Ritonavir; Sulfonamides; Swine; Verapamil

A reversed-phase high-performance liquid chromatographic method for the simultaneous quantitative determination of five HIV protease inhibitors (i.e. indinavir, amprenavir, saquinavir, ritonavir and nelfinavir) in human plasma is described. An aliquot of 500 microl plasma was extracted with 0.5 ml of 0.1 M NH4OH and 5 ml of methyl tert.-butyl ether. After evaporating, the residue was dissolved in eluent mixture of acetonitrile and 50 mM KH2PO4 adjusted to pH 5.6 with 50 mM Na2HPO4 (43:57, v/v). Subsequently, the eluent was washed with hexane. Chromatography was performed using a C18 reversed-phase column. Ultraviolet detection at 215 nm was used. Linearity of the method was obtained in the concentration range of 0.05-20 microg ml(-1) for all five protease inhibitors. Our method is now in use to analyse plasma samples from patients treated with co-administration of HIV protease inhibitors.

Topics: Adult; Calibration; Carbamates; Chromatography, High Pressure Liquid; Furans; HIV Protease Inhibitors; Humans; Indinavir; Male; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides

A rapid, simple and sensitive high-performance liquid chromatographic (HPLC) assay has been developed for the simultaneous quantification of the HIV-protease inhibitors indinavir, amprenavir, ritonavir, saquinavir and nelfinavir in human plasma. The method involved the solid-phase extraction of the five drugs and the internal standard (I.S., verapamil) from 400 microl of human plasma. The HPLC analysis used a reversed-phase C18 analytical column and a mobile phase consisting of a gradient with 15 mM phosphate buffer (pH 5.75)-acetonitrile and UV monitoring. The method was linear over the therapeutic concentration range for the five HIV-protease inhibitors. The accuracy of the method ranged from 98.2 to 106.7% and the precision values ranged from 1.4 to 8.1% for intra-day precision and from 3.1 to 6.4% for the inter-day values.

Topics: Carbamates; Chromatography, High Pressure Liquid; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Nelfinavir; Reference Standards; Reproducibility of Results; Ritonavir; Saquinavir; Sensitivity and Specificity; Spectrophotometry, Ultraviolet; Sulfonamides

An analytical technique using liquid chromatography (LC) coupled with electrospray-mass spectrometry (ESI--MS) has been developed for the simultaneous determination of five protease inhibitors (PIs): saquinavir, indinavir, ritonavir, nelfinavir, and amprenavir; and three non-nucleoside reverse transcriptase inhibitors (NNRTIs): nevirapine, delavirdine, and efavirenz, in human plasma. This assay allows the elution and identification of these drugs in a single run (10 minutes) using a linear gradient with water and acetonitrile. The procedure involves liquid--liquid extraction. High-performance liquid chromatography (HPLC) separation was achieved on a C18 reversed-phase column, with a linear gradient elution followed by mass spectrometry detection. The calibration curves, obtained by automatic process peak area integration, show a good linearity in a range of concentrations between 20 and 10,000 ng/mL (40--10,000 ng/mL for efavirenz). The limit of detection was approximately 10 ng/mL for seven drugs (25 ng/mL for efavirenz). The coefficients of variation (CV) were always less than 15% for both intraday and interday precision for each compound. The recovery of the eight drugs ranged from 88.5% to 100%. This novel LC/ESI--MS assay provides an excellent method for simultaneous quantitative monitoring of different components of the highly active antiretroviral treatments (HAARTs) in patients treated simultaneously with PIs and NNRTIs, and it has been successfully applied to therapeutic drug monitoring and pharmacokinetic studies.

Topics: Alkynes; Benzoxazines; Carbamates; Chromatography, Liquid; Cyclopropanes; Delavirdine; Drug Monitoring; Furans; HIV Protease Inhibitors; Humans; Indinavir; Mass Spectrometry; Nelfinavir; Nevirapine; Oxazines; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sensitivity and Specificity; Sulfonamides

A single HPLC assay was developed for therapeutic drug monitoring of 5 HIV protease inhibitors (indinavir, amprenavir, saquinavir, ritonavir, nelfinavir) and a non-nucleoside reverse transcriptase inhibitor (nevirapine) in human plasma. After liquid-liquid extraction in a mixture ethyl acetate-hexane, compounds are separated on a C18 column with a gradient elution of solvent A [acetonitrile and 0.025 M tetramethylammonium perchlorate in 0.2% aqueous trifluoroacetic acid (55:45 (v/v))] and solvent B [methanol and 0.025 M tetramethylammonium perchlorate in 0.2% aqueous trifluoroacetic acid (55:45 (v/v))]. The compounds are detected at various wavelengths: 320 nm (nevirapine), 259 nm (indinavir), 254 nm (amprenavir, nelfinavir, saquinavir) and 239 nm (ritonavir). The intra-day and inter-day precision and accuracy are lower than 15%. The limits of quantitation are 0.05 mg/l (amprenavir), 0.2 mg/l (indinavir, saquinavir, nelfinavir) and 0.4 mg/l (ritonavir, nevirapine). This method which allows to estimate simultaneously plasma levels of protease inhibitors and nevirapine can be used for therapeutic drug monitoring.

Topics: Calibration; Carbamates; Chromatography, High Pressure Liquid; Furans; HIV Protease Inhibitors; Humans; Indinavir; Nelfinavir; Nevirapine; Reference Standards; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sensitivity and Specificity; Sulfonamides

Topics: Anti-HIV Agents; Carbamates; CD4 Lymphocyte Count; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Ritonavir; Sulfonamides; Viral Load

Protease inhibitors are known by their inhibition of a viral protease that leads to production of immature and non-infectious virus particles. The novel protease inhibitor KALETRA is a co-formulation of lopinavir and ritonavir. Ritonavir reduces the metabolization of lopinavir by the cytochrome P450 3A4 isoenzyme which leads to markedly increased plasma levels of lopinavir(4). A new rapid and sensitive HPLC method for the simultaneous determination of lopinavir, indinavir, amprenavir, saquinavir, ritonavir and nelfinavir in human plasma has been developed. An aliquot of 500 microl plasma, spiked with internal standard, was extracted with 500 microl 0.1 M ammonium hydroxide solution and 5 ml tert. -butyl ether. After drying under a nitrogen stream, the residue was redissolved in an eluent consisting of 50 mM phosphate buffer, pH 5.40 and acetonitrile (50:50, v/v). Chromatographic separation was accomplished on a C-18 column using a non-linear gradient elution and ultraviolet detection at 215 nm.

Topics: Carbamates; Chromatography, High Pressure Liquid; Drug Interactions; Drug Monitoring; Drug Therapy, Combination; Furans; HIV Protease Inhibitors; Humans; Indinavir; Lopinavir; Nelfinavir; Pyrimidinones; Reproducibility of Results; Ritonavir; Saquinavir; Sulfonamides

Topics: Aged; Carbamates; CD4 Lymphocyte Count; Dideoxynucleosides; Drug Resistance, Microbial; Drug Therapy, Combination; Furans; HIV Infections; Humans; Lopinavir; Male; Patient Compliance; Pyrimidinones; Ritonavir; Stavudine; Sulfonamides; Viral Load

As part of an on-going study on the suitability of a formal therapeutic drug monitoring (TDM) of antiviral drugs for improving the management of HIV infection, a high-performance liquid chromatography method has been developed to quantify simultaneously in plasma five HIV protease inhibitors (PIs) (i.e., indinavir, amprenavir, saquinavir, ritonavir, nelfinavir) and the novel non-nucleoside reverse transcriptase inhibitor efavirenz. After viral inactivation by heat (60 degrees C for 60 min), plasma (600 microl), with clozapine added as internal standard, is diluted 1:1 with phosphate buffer, pH 7 and subjected to a solid-phase extraction on a C18 cartridge. Matrix components are eliminated with 2 x 500 microl of a solution of 0.1% H3PO4 neutralised with NaOH to pH 7. PIs and efavirenz are eluted with 3 x 500 microl MeOH. The resulting eluate is evaporated under nitrogen at room temperature and is reconstituted in 100 microl 50% MeOH. A 40-microl volume is subjected to HPLC analysis onto a Nucleosil 100, 5 microm C18 AB column, using a gradient elution of MeCN and phosphate buffer adjusted to pH 5.15 and containing 0.02% sodium heptanesulfonate: 15:85 at 0 min-->30:70 at 2 min-->32:68 at 8 min-->42:58 at 18 min-->46:54 at 34 min, followed by column cleaning with MeCN-buffer, pH 5.15 (90:10), onto which 0.3% AcOH is added. Clozapine, indinavir, amprenavir, saquinavir, ritonavir, efavirenz and nelfinavir are detected by UV at 201 nm at a retention time of 8.2, 13.0, 16.3, 21.5, 26.5, 28.7 and 31.9 min, respectively. The total run time for a single analysis is 47 min, including the washing-out and reequilibration steps. The calibration curves are linear over the range 100-10,000 ng/ml. The absolute recovery of PIs/efavirenz is always higher than 88%. The method is precise with mean inter-day relative standard deviations within 2.5-9.8% and accurate (range of inter-day deviations -4.6 to +4.3%). The in vitro stability of plasma spiked with PIs/efavirenz at 750, 3000 and 9000 ng/ml has been studied at room temperature, -20 degrees C and +60 degrees C. The method has been validated and is currently applied to the monitoring of PIs and efavirenz in HIV patients. This HPLC assay may help clinicians confronted to questionable compliance, side effects or treatment failure in elucidating whether patients are exposed to adequate circulating drug levels. The availability of such an assay represents an essential step in elucidating the utility of a formal TDM for the opt

Topics: Alkynes; Benzoxazines; Calibration; Carbamates; Chromatography, High Pressure Liquid; Cyclopropanes; Drug Stability; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Nelfinavir; Oxazines; Reproducibility of Results; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sulfonamides

Topics: Adenocarcinoma; ATP Binding Cassette Transporter, Subfamily B, Member 1; Carbamates; Cell Line, Transformed; Colonic Neoplasms; Drug Resistance, Multiple; Furans; Gene Expression Regulation, Neoplastic; HIV Protease Inhibitors; Humans; Indinavir; Ivermectin; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides; Tumor Cells, Cultured; Verapamil; Vinblastine

A sensitive and selective liquid chromatographic assay has been developed for the determination of the five protease inhibitors currently approved by the Food and Drug Administration (FDA) (amprenavir, indinavir, nelfinavir, ritonavir, and saquinavir) in a single run. Pretreatment of a 1-mL plasma sample spiked with internal standard was made by a solid-phase extraction procedure using a polymeric reversed-phase sorbent. Liquid chromatography was performed using a narrowbore C18 reversed-phase column and gradient elution. A double ultraviolet detection at 265 nm (amprenavir) and at 210 nm (indinavir, nelfinavir, ritonavir, saquinavir and internal standard) was used. Calibration curves were linear in the range 25-10000 ng/mL and the assay has been validated over the range 25-5000 ng/mL. Average accuracy at four concentrations was in the range of 100.5-104.2% and 96.9-100.5% for within-day and between-day, respectively. The coefficients of variation were less than 10%. Mean absolute recoveries varied from 85.4% (ritonavir) to 98.8% (saquinavir). No metabolite of the protease inhibitors was found to coelute with the drugs of interest or with the internal standard. At this time, among the tested drugs, especially all the presently licensed nucleoside and nonnucleoside reverse transcriptase inhibitors that can be used in combination with the protease inhibitors, none was found to interfere with the assay. This method is now in use in the authors' laboratory for the therapeutic monitoring of the HIV-protease inhibitors.

Topics: Carbamates; Chromatography, Liquid; Drug Monitoring; Furans; HIV Protease Inhibitors; Humans; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides

The effect on humoral immune responses of highly active antiretroviral therapy (HAART) commenced during primary or chronic human immunodeficiency virus type 1 (HIV-1) infection was investigated. HAART inhibited the development of anti-gp120 antibodies when initiated during primary infection and could sometimes reduce antibody titers in patients treated within 2 years of HIV-1 infection. Conversely, antibody responses in patients infected for several years were less sensitive to HAART. Administering HAART during primary infection usually did not substantially affect the development of weak neutralizing antibody responses against autologous virus. However, 2 patients treated very early after infection did not develop neutralizing responses. In contrast, 3 of 4 patients intermittently adherent to therapy developed autologous neutralizing antibodies of unusually high titer, largely coincident with brief viremic periods. The induction of strong neutralizing antibody responses during primary HIV-1 infection might require the suppression of virus replication by HAART, to allow for the recovery of immune competency, followed by exposure to native envelope glycoproteins.

Topics: Anti-HIV Agents; Carbamates; Dideoxynucleosides; Furans; HIV Antibodies; HIV Core Protein p24; HIV Envelope Protein gp120; HIV Infections; HIV-1; Humans; Lamivudine; Neutralization Tests; Ritonavir; Sulfonamides; Zidovudine

Biotransformation of triazolam to its alpha-hydroxy and 4-hydroxy metabolites by human liver microsomes in vitro was used as an index of human cytochrome P450 3A (CYP3A) activity.. The reaction was strongly inhibited by co-incubation with the viral protease inhibitors ritonavir (IC50 = 0.14 microM) and amprenavir (IC50 = 2.5 2.9 microM), and by the azole derivative ketoconazole (IC50 = 0.07 microM). Pre-incubation of microsomes with ritonavir or amprenavir increased inhibitory potency (IC50 reduced to 0.07 microM and 1.4 microM, respectively). This was not the case with ketoconazole.. Thus, ritonavir and amprenavir are highly potent mechanism-based inhibitors of human CYP3A isoforms.

Topics: Aryl Hydrocarbon Hydroxylases; Carbamates; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Enzyme Inhibitors; Furans; Humans; Hydroxylation; Ketoconazole; Oxidoreductases, N-Demethylating; Ritonavir; Sulfonamides; Triazolam

Although numerous mutations that confer resistance to protease inhibitors (PRI) have been mapped for HIV-1 subtype B, little is known about such substitutions for the non-B viruses, which globally cause the most infections.. To determine the prevalence of PRI-associated mutations in PRI-naive individuals worldwide.. Using the polymerase chain reaction, protease sequences were amplified from 301 individuals infected with HIV-1 subtypes A (79), B (95), B' (19), C (12), D (26), A/E (23), F (26), A/G (11), and H (3) and unclassifiable HIV-1 (7). Amplified DNA was directly sequenced and translated to amino acids to analyze PRI-associated major and accessory mutations.. Of the 301 sequences, 85% contained at least one codon change giving substitution at 10, 20, 30, 36, 46, 63, 71, 77, or 82 associated with PRI resistance; the frequency of these substitutions was higher among non-B (91%) than B (75%) viruses (P < 0.0005). Of these, 25% carried dual and triple substitutions. Two major drug resistance-conferring mutations, either 20M or 30N, were identified in only three specimens, whereas drug resistance accessory mutations were found in 252 isolates. These mutations gave distinct prevalence patterns for subtype B, 63P (62%) > 77I (19%) > 10I/V/R (6%) = 361 (6%) = 71T/V (6%) > 20R (2%), and non-B strains, 36I (83%) > 63P (17%) > 10I/V/R (13%) > 20R (10%) > 77I (2%), which differed statistically at positions 20, 36, 63, 71, and 77.. The high prevalence of PRI-associated substitutions represent natural polymorphisms occurring in PRI-naive patients infected with HIV-1 strains of subtypes A-H. The significance of distinct mutation patterns identified for subtype B and non-B strains warrants further clinical evaluation. A global HIV-1 protease database is fundamental for the investigation of novel PRI.

Topics: Amino Acid Sequence; Amino Acid Substitution; Carbamates; Codon; Drug Resistance, Microbial; Furans; Global Health; HIV Protease; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Molecular Sequence Data; Mutation; Nelfinavir; Phylogeny; Ritonavir; Saquinavir; Sulfonamides

AIDS therapies employing HIV protease inhibitors (PIs) are associated with changes in fat metabolism. However, the cellular mechanisms affected by PIs are not clear. Thus, the affects of PIs on adipocyte differentiation were examined in vitro using C3H10T1/2 stem cells. In these cells the PIs, nelfinavir, saquinavir, and ritonavir, reduced triglyceride accumulation, lipogenesis, and expression of the adipose markers, aP2 and LPL. Histological analysis revealed nelfinavir, saquinavir and ritonavir treatment decreased oil red O-staining of cytoplasmic fat droplets. Inhibition occurred in the presence of the RXR agonist LGD1069, indicating the inhibitory effects were not due to an absence of RXR ligand. Moreover, these three PIs increased acute lipolysis in adipocytes. In contrast, two HIV PIs, amprenavir and indinavir, had little effect on lipolysis, lipogenesis, or expression of aP2 and LPL. Although, saquinavir, inhibited ligand-binding to PPARgamma with an IC(50) of 12.7+/-3.2 microM, none of the other PIs bound to the nuclear receptors RXRalpha or PPARgamma, (IC(50)s>20 microM), suggesting that inhibition of adipogenesis is not due to antagonism of ligand binding to RXRalpha or PPARgamma. Taken together, the results suggest that some, but not all, PIs block adipogenesis and stimulate fat catabolism in vitro and this may contribute to the effects of PIs on metabolism in the clinic.

Topics: Adipocytes; Animals; Azo Compounds; Bexarotene; Carbamates; Carrier Proteins; Cell Differentiation; Cells, Cultured; Coloring Agents; Fatty Acid-Binding Proteins; Furans; HIV Protease Inhibitors; Indinavir; Insulin; Lipolysis; Lipoprotein Lipase; Nelfinavir; Neoplasm Proteins; Receptors, Cytoplasmic and Nuclear; Receptors, Retinoic Acid; Retinoid X Receptors; Ritonavir; RNA, Messenger; Rosiglitazone; Saquinavir; Stem Cells; Sulfonamides; Tetrahydronaphthalenes; Thiazoles; Thiazolidinediones; Transcription Factors; Triglycerides

Topics: Alkynes; Anti-HIV Agents; Aryl Hydrocarbon Hydroxylases; Benzoxazines; Carbamates; Cyclopropanes; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Drug Interactions; Drug Therapy, Combination; Furans; HIV Infections; Humans; Oxazines; Oxidoreductases, N-Demethylating; Ritonavir; Sulfonamides

The therapeutic success of an antiretroviral salvage regimen containing protease inhibitors (PI) is limited by PI-resistant viral strains exhibiting various degrees of resistance and cross-resistance. To evaluate the extent of cross-resistance to the new PI amprenavir, 155 samples from 132 human immunodeficiency virus type 1-infected patients were analyzed for viral genotype by direct sequencing of the protease gene. Concomitantly, drug sensitivity to indinavir, saquinavir, ritonavir, nelfinavir, and amprenavir was analyzed by a recombinant virus assay. A total of 111 patients had been pretreated with 1-4 PI, but all were naive to amprenavir. A total of 105 samples (67.7%) were sensitive to amprenavir; 25 samples (16.1%) were intermediately resistant, and another 25 samples were highly resistant (4- to 8-fold- and >8-fold-reduced sensitivity, respectively). The mutations 46I/L, 54L/V, 84V, and 90M showed the strongest association with amprenavir resistance (P < 0. 0001). The scoring system using 84V and/or any two of a number of mutations (10I/R/V/F, 46I/L, 54L/V, and 90M) predicted amprenavir resistance with a sensitivity of 86.0% and a specificity of 81.0% within the analyzed group of samples. Of 62 samples with resistance against 4 PI, 23 (37.1%) were still sensitive to amprenavir. In comparison, only 2 of 23 samples (8.7%) from nelfinavir-naive patients with resistance against indinavir, saquinavir, and ritonavir were still sensitive to nelfinavir. Amprenavir thus appears to be an interesting alternative for PI salvage therapy.

Topics: Carbamates; Drug Resistance, Microbial; Drug Resistance, Multiple; Furans; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Indinavir; Ritonavir; Saquinavir; Sulfonamides

Topics: Acquired Immunodeficiency Syndrome; Acute Disease; Anti-HIV Agents; Carbamates; Coronary Disease; Dideoxynucleosides; Drug Therapy, Combination; Furans; Hepatitis B; HIV Protease Inhibitors; Humans; Hyperlipoproteinemias; Male; Middle Aged; Pancreatitis; Risk Factors; Ritonavir; Sulfonamides

To optimize the conditions for determining Caco-2 permeation of HIV protease inhibitors and other lipophilic compounds, and to compare cyclic urea HIV protease inhibitors with marketed compounds.. Absorptive and secretory Caco-2 membrane permeation studies were performed with HIV protease inhibitors and various reference compounds, examining the effects of adding the solubilizing agents dimethylacetamide (DMAC) and albumin in donor and reservoir compartments, respectively.. DMAC was useful as an additive in the donor vehicles, increasing the dissolved concentrations of poorly water-soluble HIV protease inhibitors, and enabling more reliable determination of P(app) values. Donor vehicles containing up to 5% DMAC could be used without altering Caco-2 barrier function, as indicated by the lack of effect on permeabilities of reference compounds with diverse absorption characteristics. The utilization of a reservoir containing albumin resulted in marked increases in absorptive Papp values for some HIV protease inhibitors as well as other lipophilic, highly protein bound compounds, consistent with albumin increasing the release of these compounds from the cell monolayer.. Poorly soluble, lipophilic, highly bound compounds may require using solubilizing agents in the donor and reservoir compartments of Caco-2 permeation experiments for estimating in vivo absorption potential. If the reservoir does not provide adequate sink conditions, cellular retention could over-emphasize the contributions of secretory transport. The cyclic ureas, DMP 450, DMP 850, and DMP 851, have Caco-2 permeabilities suggestive of moderate-to-high oral absorption potential in humans.

Topics: Acetamides; Albumins; Azepines; Caco-2 Cells; Carbamates; Cell Membrane Permeability; Furans; HIV Protease Inhibitors; Humans; Indinavir; Intestinal Absorption; Nelfinavir; Ritonavir; Solvents; Structure-Activity Relationship; Sulfonamides; Urea

Topics: Alkynes; Antiretroviral Therapy, Highly Active; Benzoxazines; Carbamates; Cyclopropanes; Drug Interactions; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Oxazines; Reverse Transcriptase Inhibitors; Ritonavir; Sulfonamides; Viral Load

Topics: Adult; Anti-HIV Agents; Carbamates; Drug Therapy, Combination; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lamivudine; Male; Middle Aged; Reverse Transcriptase Inhibitors; Ritonavir; Salvage Therapy; Saquinavir; Sulfonamides; Zidovudine

To determine the role of P-glycoprotein (Pgp) on the CNS penetration of the HIV protease inhibitor (PI) amprenavir (141W94) and to test the hypothesis that co-administration of a second HIV PI (ritonavir) could enhance amprenavir's brain penetration in vivo.. Pgp-mediated efflux was investigated in vitro with Caco-2 cells and in vivo by whole-body autoradiography (WBA). "Genetic" mdr1a/1b double knockout mice, "chemical" Pgp knockout mice generated by administration of the Pgp inhibitor GF120918, and mice pretreated with ritonavir were used in WBA studies to investigate the effects of Pgp modulation on the CNS penetration of amprenavir.. Amprenavir, indinavir, ritonavir, and saquinavir had 2- to 23-fold higher transport rates from the basolateral to apical direction than from the apical to basolateral direction across Caco-2 monolayers. Incubation with GF120918 negated this difference, suggesting that the efflux was Pgp-mediated. WBA studies demonstrated a 13- and 27-fold increase in the brain and a 3.3-fold increase in the CSF concentrations of amprenavir in mice pretreated with GF120918 and in mdr1a/1b double knockout mice. In contrast, pretreatment with ritonavir did not alter the CNS exposure of amprenavir.. These results provide evidence that amprenavir and other HIV PIs are Pgp substrates and that co-administration of a specific Pgp inhibitor will enhance amprenavir's CNS penetration in vivo. These results will have an important therapeutic impact in the treatment of AIDS dementia.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Autoradiography; Biological Transport; Caco-2 Cells; Carbamates; Cattle; Central Nervous System; Drug Interactions; Furans; HIV Protease Inhibitors; Humans; Male; Mice; Mice, Knockout; Ritonavir; Sulfonamides; Whole-Body Irradiation

Patients with AIDS who are receiving therapy with HIV protease inhibitors have been widely reported to be afflicted with a syndrome characterized by lipodystrophy (fat redistribution favoring the accumulation of abdominal and cervical adipose tissue), hyperlipidemia, and insulin resistance. HIV protease inhibitors have been suggested to have a direct role in modulating adipocyte differentiation. To address this hypothesis, several HIV protease inhibitors were studied for their ability to either augment or inhibit the differentiation of murine 3T3-L1 preadipocytes. Dose-responsive inhibition of adipogenesis by several protease inhibitors was noted as measured by reduced triglyceride accumulation and attenuated induction of three differentiation marker genes -- aP2, lipoprotein lipase, and Adipo Q. Potential mechanisms for altered adipocyte function, including direct binding to PPARgamma or inhibition of PPARgamma-mediated gene transcription were effectively excluded.

Topics: 3T3 Cells; Adipocytes; Adiponectin; Animals; Carbamates; Carrier Proteins; Cell Differentiation; Dose-Response Relationship, Drug; Fatty Acid-Binding Protein 7; Fatty Acid-Binding Proteins; Furans; Gene Expression; Glycoproteins; HIV Protease Inhibitors; Humans; Indinavir; Intercellular Signaling Peptides and Proteins; Lipoprotein Lipase; Mice; Myelin P2 Protein; Nelfinavir; Neoplasm Proteins; Nerve Tissue Proteins; Proteins; Receptors, Cytoplasmic and Nuclear; Recombinant Proteins; Ritonavir; Stem Cells; Sulfonamides; Transcription Factors; Triglycerides; Tumor Suppressor Proteins

Updates are provided for new anti-HIV drugs currently in development. ABT-378, Tipranavir, and DMP-450 are among the new protease inhibitors discussed. Drugs from other classes that are discussed include emivirine (Coactinon, formerly MKC-442), FTC (emtricitabine, Coviracil), adefovir (Preveon), and pentafuside (T-20). A small study has found that women using Ritonavir (Norvir) may be at a greater risk for anemia (a decrease in red blood cells), caused by excessive menstrual bleeding or hypermenorrhea. New formulations of Ritonavir and ddI (Didanosine, Videx) are described.

Topics: Adverse Drug Reaction Reporting Systems; Anti-HIV Agents; Capsules; Carbamates; Chemistry, Pharmaceutical; Didanosine; Drug Synergism; Drug Therapy, Combination; Drugs, Investigational; Female; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lopinavir; Menorrhagia; Pyrimidinones; Reverse Transcriptase Inhibitors; Ritonavir; Sulfonamides

Recent experimental findings with HIV-1 protease (HIV-1 PR) mutants containing variations at four residues, M46I, L63P, V82T and I84V, have shown that only mutants containing the latter two exhibit cross resistance to the inhibitors ABT-538 and VX-478. The V82T and I84V modifications in fact concern residues in the active site while the other two are in the flap (M46I) and hinge (L63P) domains of the enzyme. We have modelled the M46I/L63P, V82T/I84V and M46I/L63P/ V82T/I84V (4X) mutants of HIV-PR and computed their complexation energies with these two inhibitors. A good correlation was found between these complexation energies and the trend in published inhibition constants for these inhibitors. Reasons for the decrease in binding affinities with the two critical mutants (V82T/I84V and 4X) have also been elucidated in detail. Based on these findings, we have designed several analogues of ABT-538 and VX-478, some of which show a better calculated binding affinity towards both mutant and wild type PR.

Topics: Binding Sites; Carbamates; Computer Simulation; Drug Design; Drug Resistance; Furans; HIV Protease; HIV Protease Inhibitors; Models, Molecular; Molecular Conformation; Mutagenesis, Site-Directed; Protein Binding; Ritonavir; Sulfonamides

Amprenavir (141W94, VX-478, KVX-478) is metabolized primarily by CYP3A4 (cytochrome P450 3A4) in recombinant systems and human liver microsomes (HLM). The effects of ketoconazole, terfenadine, astemizole, rifampicin, methadone, and rifabutin upon amprenavir metabolism were examined in vitro using HLM. Ketoconazole, terfenadine, and astemizole were observed to inhibit amprenavir depletion, consistent with their known specificity for CYP3A4. The HIV protease inhibitors, indinavir, saquinavir, ritonavir, and nelfinavir, were included in incubations containing amprenavir to examine the interactions of HIV protease inhibitors in vitro. The order of amprenavir metabolism inhibition in human liver microsomes was observed to be: ritonavir > indinavir > nelfinavir > saquinavir. The Ki value for amprenavir-mediated inhibition of testosterone hydroxylation in human liver microsomes was found to be approximately 0.5 microM. Studies suggest that amprenavir inhibits CYP3A4 to a greater extent than saquinavir, and to a much lesser extent than ritonavir. Amprenavir, nelfinavir, and indinavir appear to inhibit CYP3A4 to a moderate extent, suggesting a selected number of coadministration restrictions.

Topics: Anti-HIV Agents; Carbamates; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Interactions; Enzyme Inhibitors; Furans; HIV Protease Inhibitors; Humans; Isoenzymes; Microsomes, Liver; Mixed Function Oxygenases; Ritonavir; Saquinavir; Sulfonamides

To examine the relationship between HIV protease genotype and altered protease inhibitor sensitivity of isolates from patients after therapy with saquinavir (SQV) in its hard gelatin formulation.. Forty-one post-therapy isolates and corresponding baseline samples were obtained from 37 patients in four different clinical trials after therapy with SQV for 16-147 weeks. Post-therapy isolates were selected on the basis of preliminary sequence or drug sensitivity data.. Fifteen out of 17 isolates without detectable Val-48 or Met-90 mutations retained sensitivity to SQV. (The remaining isolates showed only a marginal increase in median inhibitory concentration.) In addition, three out of 15 isolates with Met-90 retained sensitivity to all other protease inhibitors tested (indinavir, ritonavir, amprenavir, nelfinavir). Of the isolates showing reduced sensitivity to SQV, six out of 22 retained sensitivity to all other protease inhibitors, whereas only four out of 22 showed broad cross-resistance to all protease inhibitors tested. The reduction in sensitivity correlated closely with the presence of Val-48 or Met-90. Subsequent accessory substitutions were also linked to reduced sensitivity. However, significant linkage was observed only between mutations at residues 48 and 82 and between those at residues 82 and 74.. Recruitment of Val-48/Met-90 mutations was not found to be synonymous with cross-resistance. Indeed, the majority of isolates with these mutations retained sensitivity to at least one protease inhibitor (Val-48, 86%; Met-90, 77%). The recruitment of accessory mutations may occur only after the selection of key resistance mutations. Furthermore, Met-90 was found to be a poor marker of cross-resistance in SQV-treated patients.

Topics: Amino Acid Substitution; Carbamates; Clinical Trials as Topic; Databases, Factual; DNA, Viral; Furans; Genetic Linkage; Genotype; HIV Infections; HIV Protease; HIV Protease Inhibitors; Humans; Indinavir; Methionine; Nelfinavir; Phenotype; Polymerase Chain Reaction; Ritonavir; Saquinavir; Sulfonamides; Valine

Topics: Acquired Immunodeficiency Syndrome; Anti-HIV Agents; Carbamates; Dideoxynucleosides; Drug Therapy, Combination; Furans; HIV Protease Inhibitors; Humans; Indinavir; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides; Viral Load

Protein binding can impair the potency of human immunodeficiency virus (HIV) protease inhibitors. Therefore, the activity of a novel compound, CGP 61755, was studied in the absence or presence of alpha1-acid glycoprotein (alpha1AGP). In MT-2 cells, the activity loss was 4-fold (EC90 without alpha1AGP, 29 nM vs. 122 nM with alpha1AGP). In primary lymphocytes, the loss was 8-fold (EC90, 45 nM vs. 364 nM). In identical experiments, the activity loss in MT-2 cells and lymphocytes was 2- and 3-fold, respectively, for indinavir, 11- and 10-fold for saquinavir, and 11- and 48-fold for ritonavir. For SC-52151, a 17-fold loss was seen in MT-2 cells, whereas no EC90 with alpha1AGP was reached in lymphocytes. This study demonstrates that the impact of alpha1AGP on in vitro activity varies greatly among different HIV protease inhibitors. The magnitude of such differences is greater in human lymphocytes than in a standard cell line.

Topics: Anti-HIV Agents; Carbamates; Cell Line; Cells, Cultured; Ethylenes; Furans; HIV Protease Inhibitors; HIV Seronegativity; HIV-1; Humans; Indinavir; Kinetics; Lymphocytes; Orosomucoid; Ritonavir; Saquinavir; Sulfonamides; Urea; Virus Replication

Site-specific substitutions of as few as four amino acids (M46I/L63P/V82T/I84V) of the human immunodeficiency virus type 1 (HIV-1) protease engenders cross-resistance to a panel of protease inhibitors that are either in clinical trials or have recently been approved for HIV therapy (Condra, J. H., Schleif, W. A., Blahy, O. M. , Gadryelski, L. J., Graham, D. J., Quintero, J. C., Rhodes, A., Robbins, H. L., Roth, E., Shivaprakash, M., Titus, D., Yang, T., Teppler, H., Squires, K. E., Deutsch, P. J., and Emini, E. A. (1995) Nature 374, 569-571). These four substitutions are among the prominent mutations found in primary HIV isolates obtained from patients undergoing therapy with several protease inhibitors. Two of these mutations (V82T/I84V) are located in, while the other two (M46I/L63P) are away from, the binding cleft of the enzyme. The functional role of these mutations has now been delineated in terms of their influence on the binding affinity and catalytic efficiency of the protease. We have found that the double substitutions of M46I and L63P do not affect binding but instead endow the enzyme with a catalytic efficiency significantly exceeding (110-360%) that of the wild-type enzyme. In contrast, the double substitutions of V82T and I84V are detrimental to the ability of the protease to bind and, thereby, to catalyze. When combined, the four amino acid replacements institute in the protease resistance against inhibitors and a significantly higher catalytic activity than one containing only mutations in its active site. The results suggest that in raising drug resistance, these four site-specific mutations of the protease are compensatory in function; those in the active site diminish equilibrium binding (by increasing Ki), and those away from the active site enhance catalysis (by increasing kcat/KM). This conclusion is further supported by energy estimates in that the Gibbs free energies of binding and catalysis for the quadruple mutant are quantitatively dictated by those of the double mutants.

Topics: Carbamates; Clinical Trials as Topic; Furans; Fusion Proteins, gag-pol; HIV Protease; HIV Protease Inhibitors; Humans; Hydrolysis; Indinavir; Kinetics; Mutagenesis; Ritonavir; Sulfonamides

Mutations in the human immunodeficiency virus (HIV) protease (L90M, G48V, and L90M/G48V) arise when HIV is passaged in the presence of the HIV protease inhibitor saquinavir. These mutations yield a virus with less sensitivity to the drug (L90M > G48V >> L90M/G48V). L90M, G48V, and L90M/G48V proteases have 1/20, 1/160, and 1/1000 the affinity for saquinavir compared to WT protease, respectively. Therefore, the affinity of mutant protease for saquinavir decreased as the sensitivity of the virus to saquinavir decreased. Association rate constants for WT and mutant proteases with saquinavir were similar, ranging from 2 to 4 x 10(7) M-1 s-1. In contrast, the dissociation rate constants for WT, L90M, G48V, and L90M/G48V proteases complexed with saquinavir were 0.0014, 0.019, 0.128, and 0. 54 s-1, respectively. This indicated that the reduced affinity for mutant proteases and saquinavir is primarily the result of larger dissociation rate constants. The increased dissociation rate constants may be the result of a decrease in the internal equilibrium between the bound inhibitor with the protease flaps up and the bound inhibitor with the flaps down. Interestingly, the affinity of these mutant proteases for VX-478, ABT-538, AG-1343, or L-735,524 was not reduced as much as that for saquinavir. Finally, the catalytic constants of WT and mutant proteases were determined for eight small peptide substrates that mimic the viral cleavage sites in vivo. WT and L90M proteases had similar catalytic constants for these substrates. In contrast, G48V and L90M/G48V proteases had catalytic efficiency (kcat/Km) values with TLNF-PISP, RKIL-FLDG, and AETF-YVDG that were 1/10 to 1/20 the value of WT protease. The decreased catalytic efficiencies were primarily the result of increased Km values. Thus, mutations in the protease decrease the affinity of the enzyme for saquinavir and the catalytic efficiency with peptide substrates.

Topics: Antiviral Agents; Carbamates; Drug Resistance, Microbial; Furans; HIV Protease; HIV Protease Inhibitors; Humans; Indinavir; Isoquinolines; Kinetics; Mutagenesis; Nelfinavir; Ritonavir; Saquinavir; Sulfonamides; Sulfonic Acids

Research topics presented at the 36th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) are highlighted. Topics include the clinical benefits of 3TC (lamivudine), combination ritonavir/saquinavir therapy, and results of an initial study of a new protease inhibitor, 141W94, under development by Glaxo Wellcome.

Topics: Acetamides; Acetophenones; Anti-HIV Agents; Carbamates; CD4 Lymphocyte Count; Clinical Trials as Topic; Disease Progression; Drug Therapy, Combination; Drugs, Investigational; Furans; HIV Infections; HIV Protease Inhibitors; Humans; Lamivudine; Reverse Transcriptase Inhibitors; Ritonavir; Saquinavir; Sulfonamides; Viral Load

An overview of the Fourth International Workshop on HIV Drug Resistance held in 1995 is presented. Topics concern the dual resistance to AZT and 3TC, viral resistance to protease inhibitors, and recent laboratory findings on viral resistance patterns that have provided impetus for the design of clinical studies to evaluate rational combinations of protease inhibitors. VX-478, indinavir, and ritonavir study data are presented.

Topics: Antiviral Agents; Carbamates; CD4 Lymphocyte Count; Drug Resistance, Microbial; Furans; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Isoquinolines; Lamivudine; Pyridines; Quinolines; Ritonavir; Saquinavir; Sulfonamides; Thiazoles; Valine; Viremia; Zalcitabine; Zidovudine