tipranavir and efavirenz

Dolutegravir (DTG) is an unboosted, integrase inhibitor for the treatment of HIV infection. Two studies evaluated the effects of efavirenz (EFV) and tipranavir/ritonavir (TPV/r) on DTG pharmacokinetics (PK) in healthy subjects.. The first study was an open-label crossover where 12 subjects received DTG 50 mg every 24 hours (q24h) for 5 days, followed by DTG 50 mg and EFV 600 mg q24h for 14 days. The second study was an open-label crossover where 18 subjects received DTG 50 mg q24h for 5 days followed by TPV/r 500/200 mg every 12 hours (q12h) for 7 days and then DTG 50 mg q24h and TPV/r 500/200 mg q12h for a further 5 days. Safety assessments and serial PK samples were collected. Non-compartmental PK analysis and geometric mean ratios and 90% confidence intervals were generated.. The combination of DTG with EFV or TPV/r was generally well tolerated. Four subjects discontinued the TPV/r study due to increases in alanine aminotransferase that were considered related to TPV/r. Co-administration with EFV resulted in decreases of 57, 39 and 75% in DTG AUC(0-τ), Cmax and Cτ, respectively. Co-administration with TPV/r resulted in decreases of 59, 46 and 76% in DTG AUC(0-τ), Cmax and Cτ, respectively.. Given the reductions in exposure and PK/pharmacodynamic relationships in phase II/III trials, DTG should be given at an increased dose of 50 mg twice daily when co-administered with EFV or TPV/r, and alternative regimens without inducers should be considered in integrase inhibitor-resistant patients.

Topics: Adult; Aged; Alkynes; Anti-HIV Agents; Area Under Curve; Benzoxazines; Cross-Over Studies; Cyclopropanes; Drug Combinations; Drug Interactions; Female; Heterocyclic Compounds, 3-Ring; HIV Integrase Inhibitors; Humans; Male; Middle Aged; Models, Biological; Oxazines; Piperazines; Pyridines; Pyridones; Pyrones; Ritonavir; Sulfonamides; Young Adult

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

In Brazil, where three distinct HIV-1 subtypes (B, F, and C) cocirculate, a significant portion of the HIV-infected population has been exposed to antiretroviral drugs. This study analyzes the antiretroviral resistance profiles of HIV-1-infected individuals failing antiretroviral therapy. Genotypic resistance profiles of 2474 patients presenting virologic failure to antiretroviral therapy in the city of São Paulo, Brazil, were generated and analyzed. Resistance mutations to protease inhibitors and nucleoside reverse transcriptase inhibitors were less common in subtype C viruses, whereas nonnucleoside reverse transcriptase inhibitor resistance mutations were less common in subtype F viruses. The thymidine analog mutation pathway known as pathway 1 was more prevalent in subtype B viruses than in subtype C viruses, whereas pathway 2 was more prevalent in subtype C viruses. Selected resistance mutations varied according to subtype for all three classes of antiretrovirals. We describe two distinct pathways of nonnucleoside reverse transcriptase inhibitor resistance (to nevirapine and efavirenz). Although cross-resistance to etravirine should occur more frequently among individuals failing nevirapine treatment, the prevalence of cross-resistance to etravirine, darunavir, and tipranavir was found to be low. We found that increases in the number of resistance mutations will be related to increases in the viral load. Special attention should be given to resistance profiles in non-B subtype viruses. The accumulation of knowledge regarding such profiles in the developing world is desirable.

Topics: Alkynes; Benzoxazines; Brazil; Cohort Studies; Cyclopropanes; Darunavir; Drug Resistance, Multiple, Viral; HIV Infections; HIV Protease Inhibitors; HIV-1; Humans; Mutation; Nevirapine; Nitriles; Pyridazines; Pyridines; Pyrimidines; Pyrones; Reverse Transcriptase Inhibitors; Sulfonamides; Treatment Failure; Viral Load

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

Previously it has been shown that tipranavir-ritonavir (TPV/r) does not affect efavirenz (EFV) plasma concentrations. This study investigates the effect of steady-state EFV on steady-state TPV/r pharmacokinetics. This was a single-center, open-label, multiple-dose study of healthy adult female and male volunteers. TPV/r 500/200 mg twice a day (BID) was given with food for 24 days. After dosing with TPV/r for 10 days, EFV 600 mg once a day was added to the regimen. Intensive pharmacokinetic (PK) sampling was done on days 10 and 24. Validated bioanalytical high-pressure liquid chromatography-tandem mass spectrometry methods were used to determine plasma tipranavir (TPV), ritonavir (RTV), and EFV concentrations. Thirty-four subjects were entered into the study, and 16 subjects completed it. The geometric mean ratios (90% confidence intervals) for TPV and RTV area under the curves, C(max)s, and C(min)s comparing TPV/r alone and in combination with EFV were 0.97 (0.87 to 1.09), 0.92 (0.81 to 1.03), and 1.19 (0.93 to 1.54) for TPV and 1.03 (0.78 to 1.38), 0.92 (0.65 to 1.30), and 1.04 (0.72 to 1.48) for RTV. Frequently observed adverse events were diarrhea, headache, dizziness, abnormal dreams, and rash. EFV had no effect on the steady-state PK of TPV or RTV, with the exception of a 19% increase in the TPV C(min), which is not clinically relevant. TPV/r can be safely coadministered with EFV and without the need for a dose adjustment.

Topics: Adolescent; Adult; Alkynes; Anti-HIV Agents; Benzoxazines; Cyclopropanes; Drug Interactions; Female; Humans; Male; Middle Aged; Pyridines; Pyrones; Ritonavir; Sulfonamides

The new non-peptidic protease inhibitor tipranavir is used boosted with ritonavir in a 500/200 mg bid scheme. Multiple drug interactions are described for both drugs because of their different action in CYP450 3A4 and p-glycoprotein. In this retrospective analysis of 22 patients during therapy with tipranavir/ritonavir (TPV) 500 mg/200 mg bid, we found significantly decreased TPV-trough levels in combination with tenofovir (15.32+/-5.22 microg/ml) in comparison to TPV trough levels without tenofovir (20.21+/-14.87 microg/ml). Therapeutic drug monitoring of TPV is recommended.

Topics: Adenine; Alkynes; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Benzoxazines; Cyclopropanes; Drug Interactions; Drug Monitoring; Enfuvirtide; HIV Envelope Protein gp41; HIV Infections; Humans; Organophosphonates; Peptide Fragments; Pyridines; Pyrones; Retrospective Studies; Ritonavir; Sulfonamides; Tenofovir

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

Metabolism of the antimalarial drug amodiaquine (AQ) into its primary metabolite, N-desethylamodiaquine, is mediated by CYP2C8. We studied the frequency of CYP2C8 variants in 275 malaria-infected patients in Burkina Faso, the metabolism of AQ by CYP2C8 variants, and the impact of other drugs on AQ metabolism. The allele frequencies of CYP2C8*2 and CYP2C8*3 were 0.155 and 0.003, respectively. No evidence was seen for influence of CYP2C8 genotype on AQ efficacy or toxicity, but sample size limited these assessments. The variant most common in Africans, CYP2C8(*)2, showed defective metabolism of AQ (threefold higher K(m) and sixfold lower intrinsic clearance), and CYP2C8(*)3 had markedly decreased activity. Considering drugs likely to be coadministered with AQ, the antiretroviral drugs efavirenz, saquinavir, lopinavir, and tipranavir were potent CYP2C8 inhibitors at clinically relevant concentrations. Variable CYP2C8 activity owing to genetic variation and drug interactions may have important clinical implications for the efficacy and toxicity of AQ.

Topics: Alkynes; Amodiaquine; Antimalarials; Aryl Hydrocarbon Hydroxylases; Benzoxazines; Burkina Faso; Chromatography, High Pressure Liquid; Cyclopropanes; Cytochrome P-450 CYP2C8; Dose-Response Relationship, Drug; Drug Interactions; Enzyme Inhibitors; Genotype; HIV Protease Inhibitors; Humans; Lopinavir; Malaria, Falciparum; Models, Biological; Polymorphism, Genetic; Pyridines; Pyrimidinones; Pyrones; Reverse Transcriptase Inhibitors; Saquinavir; Spectrophotometry, Ultraviolet; Sulfonamides; Treatment Outcome; Trimethoprim