Treatment response to unboosted atazanavir in combination with tenofovir disoproxil fumarate and lamivudine in human immunodeficiency virus-1-infected patients who have achieved virological suppression: A therapeutic drug monitoring and pharmacogenetic study

Association between the UGT1A1*28 allele and hyperbilirubinemia in HIV-positive patients receiving atazanavir: a meta-analysis

Objectives The uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1)*28 allele in HIV-positive patients receiving atazanavir (ATV) might be associated with the risk of hyperbilirubinemia. Owing to mixed and inconclusive results, a meta-analysis was conducted to systematically summarize and clarify this association.

Methods Based on a comprehensive search of PubMed, Embase and Web of Science databases, studies investigating the association between UGT1A1 alleles and hyperbilirubinemia was retrieved. We evaluated the strength of this relationship using odds ratios (ORs) with 95% confidence intervals (CIs). Sensitivity analysis was performed by removing each study one at a time and calculating the pooled ORs of the remaining studies to test the robustness of the meta-analysis results. The Q statistic and the I² index statistic were used to assess heterogeneity. Publication bias was evaluated using Orwin’s fail-safe N test.

Results A total of six individual studies were included in this meta-analysis. A significantly increased risk of hyperbilirubinemia was observed in HIV-positive patients receiving ATV with the UGT1A1*1/*28 or UGT1A1*28/*28 genotype, and the risk was higher with the UGT1A1*28/*28 genotype than with the UGT1A1*1/*28 genotype. (UGT1A1*28/*28 versus UGT1A1*1/*28: OR = 3.69, 95%CI = 1.82–7.49; UGT1A1*1/*28 versus UGT1A1*1/*1: OR = 3.50, 95%CI = 1.35–9.08; UGT1A1*28/*28 versus UGT1A1*1/*1: OR = 10.07, 95%CI = 4.39–23.10). All of the pooled ORs were not significantly affected by the remaining studies and different modeling methods, indicating robust results.

Conclusions This meta-analysis suggests that the UGT1A1*28 allele represents a biomarker for an increased risk of hyperbilirubinemia in HIV-positive patients receiving ATV.

Effectiveness of switching from protease inhibitors to dolutegravir in combination with nucleoside reverse transcriptase inhibitors as maintenance antiretroviral therapy among HIV-positive patients

Prolonged exposure to regimens containing protease inhibitors (PIs) as second-line therapy for human immunodeficiency virus (HIV) infection may have a negative impact on metabolic profiles and increase the risk of cardiovascular diseases. Real-world experience with dolutegravir (DTG)-based regimens as alternatives to PI-based regimens is limited in antiretroviral-experienced patients with previous failure or intolerance to first-line therapy. The current study included HIV-positive patients receiving PI-containing regimens with viral suppression for ≥6 months. Virological response and lipid profiles were compared between patients who were subsequently switched to DTG-based therapy plus nucleoside reverse transcriptase inhibitors (NRTIs) and those remaining on their PI-containing regimen at Week 48. In total, 189 patients were switched to DTG-based regimens and 313 remained on PI-containing regimens during the observation period. Patients in the DTG group were younger (mean age 40.0 years vs. 44.6 years) and were more likely to have a previous history of virological failure (44.4% vs. 19.5%) than those in the PI group. At Week 48, 1.1% of the DTG group and 3.8% of the PI group had virological non-response (HIV-RNA load >50 copies/mL) (difference, -2.7%, 95% CI -5.5% to 0.5%). The presence of M184V/I mutation and other NRTI resistance-associated mutations (RAMs) did not increase the risk of virological failure in either group. Patients switched to DTG-based therapy had statistically significant improvement of lipid profiles. Among virally suppressed HIV-positive patients, a switch to DTG-based therapy was non-inferior to continuation of PI-based therapy in virological effectiveness at Week 48, even in the presence of NRTI RAMs.

Antiretroviral Drug Metabolism in Humanized PXR-CAR-CYP3A-NOG Mice

Antiretroviral drug (ARV) metabolism is linked largely to hepatic cytochrome P450 activity. One ARV drug class known to be metabolized by intestinal and hepatic CYP3A are the protease inhibitors (PIs). Plasma drug concentrations are boosted by CYP3A inhibitors such as cobisistat and ritonavir (RTV). Studies of such drug-drug interactions are limited since the enzyme pathways are human specific. While immune-deficient mice reconstituted with human cells are an excellent model to study ARVs during human immunodeficiency virus type 1 (HIV-1) infection, they cannot reflect human drug metabolism. Thus, we created a mouse strain with the human pregnane X receptor, constitutive androstane receptor, and CYP3A4/7 genes on a NOD.Cg-Prkdcscid Il2rgtm1Sug /JicTac background (hCYP3A-NOG) and used them to evaluate the impact of human CYP3A metabolism on ARV pharmacokinetics. In proof-of-concept studies we used nanoformulated atazanavir (nanoATV) with or without RTV. NOG and hCYP3A-NOG mice were treated weekly with 50 mg/kg nanoATV alone or boosted with nanoformulated ritonavir (nanoATV/r). Plasma was collected weekly and liver was collected at 28 days post-treatment. Plasma and liver atazanavir (ATV) concentrations in nanoATV/r-treated hCYP3A-NOG mice were 2- to 4-fold higher than in replicate NOG mice. RTV enhanced plasma and liver ATV concentrations 3-fold in hCYP3A-NOG mice and 1.7-fold in NOG mice. The results indicate that human CYP3A-mediated drug metabolism is reduced compared with mouse and that RTV differentially affects human gene activity. These differences can affect responses to PIs in humanized mouse models of HIV-1 infection. Importantly, hCYP3A-NOG mice reconstituted with human immune cells can be used for bench-to-bedside translation.