Objective.

 Nevirapine is metabolized by cytochrome P450 (CYP) 2B6 and CYP3A4, We characterized relationships between clinical parameters, human genetics, pharmacokinetics, and HIV-1 drug resistance mutations in pregnant women following single-dose intrapartum nevirapine.Methods. In AIDS Clinical Trials Group study A5207, women received nevirapine at onset of labor, and were randomized to lamivudine/zidovudine, emtricitabine/tenofovir, or lopinavir/ritonavir, for 7 or 21 days. Plasma nevirapine was quantified at post-partum day 1 and weeks 1, 3 and 5. We assayed 214 polymorphisms in CYP2B6 and other genes and evaluated associations with pharmacokinetic parameters included elimination constant, time to protein-adjusted 50% inhibitory concentration (IC50), and week 5 nevirapine below quantification limit.

Results.

 Among 301 women with evaluable pharmacokinetic and genotype data, lower body mass index and randomization to lopinavir/ritonavir were associated with more rapid nevirapine elimination. Among those of African ancestry, longer time to IC50 was associated with CYP2B6 983T→C (p=0.004) but not with CYP2B6 516G→T (p=0.8). Among Indians, slower nevirapine elimination was associated with CYP2B6 516G→T (p=0.04). Emergent resistance was infrequent and not associated with pharmacokinetics or CYP2B6 genotype.

Conclusions.

 Effects on plasma drug exposure following single-dose nevirapine may be greater for CYP2B6 983T→C than 516G→T, and are less pronounced than at steady state.

OBJECTIVES:

This study evaluates the impact of specific HIV-1 protease-compensatory mutations (wild-type amino acids in non-B subtypes) on virological response to a first-line lopinavir/ritonavir-containing regimen in an HIV-1 subtype B-infected population.

PATIENTS AND METHODS:

The prevalence of protease-compensatory mutations from 1997 to 2011 was calculated in 3063 drug-naive HIV-1 B-infected patients. The role of these mutations on virological outcome is estimated in a subgroup of 201 patients starting their first lopinavir/ritonavir-containing regimen by covariation and docking analyses.

RESULTS:

The number of HIV-1 B-infected patients with at least one protease-compensatory mutation increased over time (from 86.4% prior to 2001 to 92.6% after 2009, P = 0.02). Analysing 201 patients starting first-line lopinavir/ritonavir, the median time to virological failure was shorter in patients with at least one protease-compensatory mutation than in patients with no protease-compensatory mutations. By covariation and docking analyses, specific mutations were found to affect lopinavir affinity for HIV-1 protease and to impact virological failure. Specifically, the L10V + I13V + L63P + I93L cluster, related to fast virological failure, correlated with a decreased drug affinity for the enzyme in comparison with wild-type (ΔGmut = -30.0 kcal/mol versus ΔGwt = -42.3 kcal/mol).

CONCLUSIONS:

Our study shows an increased prevalence of specific protease-compensatory mutations in an HIV-1 B-infected population and confirms that their copresence can affect the virological outcome in patients starting a lopinavir/ritonavir-containing regimen.

A major proportion of the HIV infections worldwide is caused by group M of HIV-1 genotype and to date approximately nine subtypes and 50 circulating recombinant forms (CRFs) in the group M have been recognized. Recombinants between different HIV-1 group M subtypes are designated as CRF. The objective of this study was to present, for the first time, a HIV-1 positive case infected with CRF08_BC subtype in Turkey. In beginning of 2011, a sailor, 48-year-old male was admitted to hospital with fever, loss of appetite, weight loss, 15 days lasting diarrhea and bilateral axillary lymphadenitis. The laboratory tests yielded anti-HIV positivity, HIV-RNA positivity (129.000 copies/ml) and CD4+ T-cell count of 11 cells/mm3 (1.3%). He had a history of multiple unprotected sexual contacts during his journey to various far-east countries. His clinical level was defined as C3 according to CDC classification. Since drug resistance analysis done before the initiation of antiretroviral therapy indicated no antiretroviral resistance, tenofovir/emtricitabin + efavirenz therapy was initiated. In the 16th months of the therapy, decreasing CD4+ T-cell count, HIV-RNA positivity and worsening of clinical condition (development of herpes lesions and pulmonary tuberculosis) suggested an unresponsiveness to therapy, efavirenz was replaced with tenofovir/emtricitabin + lopinavir/ritonavir. The patient was also treated with quadruple anti-tuberculous treatment based on the clinical and radiological findings of pulmonary tuberculosis. The protease domain (codon 1-99, 330 bp) of pol gene of HIV-1 strain obtained from pretreatment plasma sample, had been amplified by nested PCR and sequenced. This HIV-1 strain was then subtyped as CRF08_BC after phylogenetic analysis with neighbor-joining method (GenBank accession number: JX536763.1). In the world, HIV-1 CRF08_BC is substantially prevalent in southwestern China among injecting drug users. Our data suggested that the CRF08_BC subtype is also present in Turkey. Molecular epidemiologic studies are important tools for tracking transmission patterns, spread and for the control of the HIV infections in a given area. Therefore, HIV molecular research should be expanded in HIV-1 infected Turkish patients. The determination of subtype CRF08_BC of HIV-1 in Turkey may be contribute to global HIV surveillance systems.

The ARTEMIS trial compared first-line antiretroviral therapy (ART) with lopinavir/ritonavir (LPV/r) to darunavir plus ritonavir (DRV + RTV) for HIV-1-infected subjects. In order to fully assess the implications of this study, economic modelling extrapolating over a longer term is required.The aim of this study was to simulate the course of HIV and its management, including the multiple factors known to be of importance in ART.A comprehensive discrete event simulation was created to represent, as realistically as possible, ART management and HIV outcomes. The model was focused on patients for whom clinicians believed that LPV/r or DRV + RTV were good options as a first regimen. Prognosis was determined by the impact of initial treatment on baseline CD4+ T-cell count and viral load, adherence, virological suppression/failure/rebound, acquired resistance mutations, and ensuing treatment changes. Inputs were taken from trial data (ARTEMIS), literature and, where necessary, stated assumptions. Clinical measures included AIDS events, side effects, time on sequential therapies, cardiovascular events, and expected life-years lost as a result of HIV infection. The model underwent face, technical and partial predictive validation. Treatment-naive individuals similar to those in the ARTEMIS trial were modelled over a lifetime, and outcomes with first-line DRV + RTV were compared with those with LPV/r, both paired with tenofovir and emtricitabine. Up to three regimen changes were permitted. Drug prices were based on wholesale acquisition cost. Outcomes were lifetime healthcare costs (in 2011 US dollars) from the US healthcare system perspective and quality-adjusted life-years (QALYs) (discounted at 3 % per annum).Choice of LPV/r over DRV + RTV as initial ART resulted in nearly identical clinical outcomes, but distinctly different economic consequences. Starting with an LPV/r regimen potentially results in approximately US$25,000 discounted lifetime savings. Accumulated QALYs for LPV/r and DRV + RTV were 12.130 and 12.083, respectively (a 19-day difference). In sensitivity analyses, net monetary benefit ranged from US$12,000 to US$31,000, favouring LPV/r (base case US$27,762).A comprehensive simulation of lifetime course of HIV in the USA indicated that using LPV/r as first-line therapy compared with DRV + RTV may result in cost savings, with similar clinical outcomes.

OBJECTIVES:

Atazanavir has been associated with kidney stones and renal failure. We measured urine and plasma concentrations of recent protease inhibitors (PIs) and searched for PI crystals in the urine of asymptomatic patients.

METHODS:

A cross-sectional analysis of HIV-infected patients taking ritonavir-boosted atazanavir 300 mg/day (ATV300/r), unboosted atazanavir 400 mg/day (ATV400), ritonavir-boosted darunavir at either 800 mg/day (DRV800/r) or 1200 mg/day (DRV1200/r) or ritonavir-boosted lopinavir 800 mg/day was performed. Plasma and urine were collected and PI levels measured using HPLC. Crystals were detected and identified in urine using polarized microscopy.

RESULTS:

PI levels were measured in 266 patients, 142 of whom were assessed for urinary crystals. Their mean age was 46 years. The mean duration of HIV infection was 10.5 years and the mean duration of the current PI-containing regimen was 22.5 months. The mean CD4 cell count was 494 cells/mm(3); 74% showed controlled HIV replication. Median urinary PI levels were 22.3, 14.3, 26.9 and 29.7 mg/L for ATV300/r, ATV400, DRV800/r and DRV1200/r, respectively, significantly higher than plasma levels, which were all <5 mg/L (P < 0.001). In contrast, median urinary lopinavir concentrrations did not significantly differ from plasma concentrations (4.2 and 6.4 mg/L, respectively; P = 0.7) and were significantly lower than those of other PIs (P < 0.001). Atazanavir crystals were found in 7/78 patients receiving ATV300/r (8.9%; 95% CI = 2.6%-15.2%) and darunavir crystals were found in 4/51 patients receiving darunavir (7.8%; 95% CI = 0.4%-15.2%). Longer exposure to atazanavir was the only risk factor associated with the presence of atazanavir crystalluria (P = 0.04).

CONCLUSIONS:

Unlike lopinavir, atazanavir and darunavir reached high concentrations in urine. Urinary crystals were found in a few patients receiving ritonavir-boosted atazanavir or darunavir and may favour nephrolithiasis.

OBJECTIVE:

African potato (Hypoxis obtusa) is commonly used in Sub-Saharan Africa as a complementary herbal remedy for HIV-infected patients. It is unknown whether or not co-administration of African potato alters the pharmacokinetics of protease inhibitor antiretrovirals. The objective of this study was to investigate the impact of the African potato on the steady-state pharmacokinetics of ritonavir-boosted lopinavir (LPV/r).

METHODS:

Sixteen adult volunteers were administered LPV/r 400/100mg twice a day for 14 days, followed by concomitant administration with African potato given once daily for 7 days. Lopinavir plasma exposure as estimated by the area under the concentration-time curve over the 12-h dosing interval (AUC0-12h, AUCτ) was determined on day 14 and again on day 21. Lopinavir in plasma was analyzed using a validated liquid chromatography with tandem mass spectrometry (LC-MS/MS) method. Steady-state AUCτ and the maximum concentration following dose administration (Cmax) were determined using non-compartmental methods using WinNonlin Professional version 5.2.1. Statistical analyses were performed using Stata version 12.1.

RESULTS:

Co-administration of African potato was not associated with any change in lopinavir AUCτ, Cmax, or Ctrough.

CONCLUSIONS:

African potato when taken concomitantly with LPV/r is well-tolerated and not associated with clinically significant changes in lopinavir pharmacokinetics.

Protease inhibitor (PI)-based antiretroviral therapy (ART) can effectively suppress HIV-2 plasma load and increase CD4 counts; however, not all PIs are equally active against HIV-2, and few data exist to support second-line therapy decisions. To identify therapeutic options for HIV-2 patients failing ART, we evaluated the frequency of PI resistance-associated amino acid changes in HIV-2 sequences from a cohort of 43 Senegalese individuals receiving unboosted indinavir (n = 18 subjects)-, lopinavir/ritonavir (n = 4)-, or indinavir and then lopinavir/ritonavir (n = 21)-containing ART. Common protease substitutions included V10I, V47A, I54M, V71I, I82F, I84V, L90M, and L99F, and most patients harbored viruses containing multiple changes. Based on genotypic data, we constructed a panel of 15 site-directed mutants of HIV-2ROD9 containing single- or multiple-treatment-associated amino acid changes in the protease-encoding region of pol. We then quantified the susceptibilities of the mutants to the HIV-2 "active" PIs saquinavir, lopinavir, and darunavir using a single-cycle assay. Relative to wild-type HIV-2, the V47A mutant was resistant to lopinavir (6.3-fold increase in the mean 50% effective concentration [EC50]), the I54M variant was resistant to darunavir and lopinavir (6.2- and 2.7-fold increases, respectively), and the L90M mutant was resistant to saquinavir (3.6-fold increase). In addition, the triple mutant that included I54M plus I84V plus L90M was resistant to all three PIs (31-, 10-, and 3.8-fold increases in the mean EC50 for darunavir, saquinavir, and lopinavir, respectively). Taken together, our data demonstrate that PI-treated HIV-2 patients frequently harbor viruses that exhibit complex patterns of PI cross-resistance. These findings suggest that sequential PI-based regimens for HIV-2 treatment may be ineffective.

Pharmacokinetics of drugs may differ between small and large mammals (including humans); therefore, drug testing in animal models must be carefully designed. Sprague-Dawley rats were used in cardiac experiments, during which the lopinavir concentration in serum had to match human therapeutic levels (4-10 μg/mL). Lopinavir was administered as a co-formulated drug of lopinavir and ritonavir. It was found that after a single administration of a standard human peroral dose (lopinavir 13.3 mg/kg of body weight), the serum concentration of lopinavir was only one-tenth of the target level. It remained below the minimum target level even after 10-fold the standard dose was administered. After initial pilot tests, a dose escalation study was conducted with oral doses 10- and 15-fold the standard clinical dose of lopinavir (i.e. 133 and 200 mg/kg, respectively). A second administration 2 h later effectively increased and maintained higher concentrations during the experimental ischaemia and reperfusion periods. A dose-dependent increase in serum concentration of the drug was observed. Thus, the target therapeutic serum level of lopinavir in the rats was achieved by administrating 10- to 15-fold the standard human dose twice, separated by a 2 h interval.