Efavirenz Pharmacogenetics and Weight Gain Following Switch to Integrase Inhibitor-Containing Regimens.

BACKGROUND: Unwanted weight gain affects some people living with human immunodeficiency virus (HIV) who are prescribed integrase strand transfer inhibitors (INSTIs). Mechanisms and risk factors are incompletely understood. METHODS: We utilized 2 cohorts to study pharmacogenetics of weight gain following switch from efavirenz- to INSTI-based regimens. In an observational cohort, we studied weight gain at 48 weeks following switch from efavirenz- to INSTI-based regimens among patients who had been virologically suppressed for at least 2 years at a clinic in the United States. Associations were characterized with CYP2B6 and UGT1A1 genotypes that affect efavirenz and INSTI metabolism, respectively. In a clinical trials cohort, we studied weight gain at 48 weeks among treatment-naive participants who were randomized to receive efavirenz-containing regimens in AIDS Clinical Trials Group studies A5095, A5142, and A5202 and did not receive INSTIs. RESULTS: In the observational cohort (n = 61), CYP2B6 slow metabolizers had greater weight gain after switch (P = .01). This was seen following switch to elvitegravir or raltegravir, but not dolutegravir. UGT1A1 genotype was not associated with weight gain. In the clinical trials cohort (n = 462), CYP2B6 slow metabolizers had lesser weight gain at week 48 among participants receiving efavirenz with tenofovir disoproxil fumarate (P = .001), but not those receiving efavirenz with abacavir (P = .65). Findings were consistent when stratified by race/ethnicity and by sex. CONCLUSIONS: Among patients who switched from efavirenz- to INSTI-based therapy, CYP2B6 genotype was associated with weight gain, possibly reflecting withdrawal of the inhibitory effect of higher efavirenz concentrations on weight gain. The difference by concomitant nucleoside analogue is unexplained.

Race/ethnicity difference in the pharmacogenetics of bilirubin-related atazanavir discontinuation.

BACKGROUND: Atazanavir causes plasma indirect bilirubin to increase. We evaluated associations between Gilbert's polymorphism and bilirubin-related atazanavir discontinuation stratified by race/ethnicity. PATIENTS AND METHODS: Patients had initiated atazanavir/ritonavir-containing regimens at an HIV primary care clinic in the southeastern USA, and had at least 12 months of follow-up data. Metabolizer group was defined by UGT1A1 rs887829 C→T. Genome-wide genotype data were used to adjust for genetic ancestry in combined population analyses. RESULTS: Among 321 evaluable patients, 15 (4.6%) had bilirubin-related atazanavir discontinuation within 12 months. Homozygosity for rs887829 T/T was present in 28.1% of Black, 21.4% of Hispanic, and 8.6% of White patients. Among all patients the hazard ratio (HR) for bilirubin-related discontinuation with T/T versus C/C genotype was 7.3 [95% confidence interval (CI): 1.7-31.5; P=0.007]. Among 152 White patients the HR was 14.4 (95% CI: 2.6-78.7; P=0.002), but among 153 Black patients the HR was 0.8 (95% CI: 0.05-12.7; P=0.87). CONCLUSION: Among patients who initiated atazanavir/ritonavir-containing regimens, UGT1A1 slow metabolizer genotype rs887829 T/T was associated with increased bilirubin-related discontinuation of atazanavir in White but not in Black patients, this despite T/T genotype being more frequent in Black patients.

Pharmacogenetics of efavirenz discontinuation for reported central nervous system symptoms appears to differ by race.

BACKGROUND: Efavirenz frequently causes central nervous system (CNS) symptoms. We evaluated genetic associations with efavirenz discontinuation for CNS symptoms within 12 months of treatment initiation. METHODS: Patients had initiated efavirenz-containing regimens at an HIV primary care clinic in the Southeastern United States and had at least 12 months of follow-up data. Polymorphisms in CYP2B6 and CYP2A6 defined efavirenz metabolizer categories. Genome-wide genotyping enabled adjustment for population stratification. RESULTS: Among 563 evaluable patients, 99 (17.5%) discontinued efavirenz within 12 months, 29 (5.1%) for CNS symptoms. The hazard ratio (HR) for efavirenz discontinuation for CNS symptoms in slow versus extensive metabolizers was 4.9 [95% confidence interval (CI): 1.9-12.4; P=0.001]. This HR in Whites was 6.5 (95% CI: 2.3-18.8; P=0.001) and 2.6 in Blacks (95% CI: 0.5-14.1; P=0.27). Considering only slow metabolizers, the HR in Whites versus Blacks was 3.1 (95% CI: 0.9-11.0; P=0.081). The positive predictive value of slow metabolizer genotypes for efavirenz discontinuation was 27% in Whites and 11% in Blacks. CONCLUSION: Slow metabolizer genotypes were associated significantly with efavirenz discontinuation for reported CNS symptoms. This association was considerably stronger in Whites than in Blacks.

Genetic and non-genetic determinants of raltegravir penetration into cerebrospinal fluid: a single arm pharmacokinetic study.

BACKGROUND: Antiretroviral drugs vary in their central nervous system penetration, with better penetration possibly conferring neurocognitive benefit during human immunodeficiency virus (HIV) therapy. The efflux transporter gene ABCB1 is expressed in the blood-brain barrier, and an ABCB1 variant (3435C → T) has been reported to affect ABCB1 expression. The integrase inhibitor raltegravir is a substrate for ABCB1. We examined whether ABCB1 3435C → T affects raltegravir disposition into cerebrospinal fluid (CSF), and explored associations with polymorphisms in other membrane transporter genes expressed in the blood-brain barrier. METHODS: Forty healthy, HIV-negative adults of European descent (20 homozygous for ABCB1 3435 C/C, 20 homozygous for 3435 T/T, each group divided equally between males and females) were given raltegravir 400 mg twice daily for 7 days. With the final dose, plasma was collected for pharmacokinetic analysis at 9 timepoints over 12 hours, and CSF collected 4 hours post dose. RESULTS: The 4-hour CSF concentration correlated more strongly with 2-hour (r(2)=0.76, P=1.12 x 10(-11)) than 4-hour (r(2)=0.47, P=6.89 x 10(-6)) single timepoint plasma concentration, and correlated strongly with partial plasma area-under-the-curve values (AUC0-4h r(2)=0.86, P=5.15 x 10(-16)). There was no significant association between ABCB1 3435C → T and ratios of CSF-to-plasma AUC or concentration (p>0.05 for each comparison). In exploratory analyses, CSF-to-plasma ratios were not associated with 276 polymorphisms across 16 membrane transporter genes. CONCLUSIONS: Among HIV-negative adults, CSF raltegravir concentrations do not differ by ABCB1 3435C → T genotype but strongly correlate with plasma exposure. TRIAL REGISTRATION: ClinicalTrials.gov NCT00729924 http://clinicaltrials.gov/show/NCT00729924.

An association between adiposity and serum levels of macrophage inflammatory protein-1α and soluble CD14 in HIV-infected adults: results from a cross-sectional study.

BACKGROUND: Greater adipose tissue is associated with increased circulating high-sensitivity C-reactive protein (hsCRP) levels in HIV-infected adults on antiretroviral therapy (ART), but the relationship between adiposity and other inflammation biomarkers is not well-characterized. METHODS: We measured total and regional adipose tissue deposits using dual energy X-ray absorptiometry (DXA) and serum levels of interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) receptor 1 and 2, macrophage inflammatory protein-1α (MIP-1α), macrophage chemotactic protein-1 (MCP-1), soluble CD14 and hsCRP in a cohort of adults on long-term ART. Regression models were adjusted for age, sex, CD4(+) T-cell count, smoking status, protease-inhibitor-use and daily use of either non-steroidal anti-inflammatory drugs or aspirin. RESULTS: The majority (77%) of the 85 study participants were male, median CD4(+) T-cell count was 500 cells/µl (IQR 315-734) and median BMI was 25.1 kg/m(2) (IQR 22.7-28.1). DXA measurements of total fat mass were positively associated with serum hsCRP (ß=1.82, P<0.01) and MIP-1α (ß=1.36, P<0.01), but negatively associated with soluble CD14 (ß=0.90, P<0.01). Results were similar for trunk fat, limb fat and serum leptin level. The positive relationship between DXA measurements and TNF-α receptor 1 approached significance (P≤0.07 for all). There was no consistent relationship between adiposity and serum IL-6, TNF-α receptor 2 or MCP-1 levels. CONCLUSIONS: Total and regional adiposity was associated with serum hsCRP, but not other inflammatory cytokines shown to predict morbidity and mortality in treated HIV. Greater adiposity is associated with higher MIP-1α and lower soluble CD14 levels, possibly reflecting an important role for cells of the monocyte/macrophage lineage.

Sex differences in urinary biomarkers of vascular and endothelial function in HIV-infected persons receiving antiretroviral therapy.

BACKGROUND: Cardiovascular disease (CVD) risk can be underestimated in HIV-infected patients receiving antiretroviral therapy (ART). Novel CVD risk markers in this population are needed. We hypothesized that eicosanoid metabolite production is increased with metabolic complications of ART. Our objective was to determine relationships between urine eicosanoids and traditional CVD risk factors in a cohort of HIV-infected persons receiving ART. METHODS: Cross-sectional analysis of 107 individuals from a prospective cohort study with urine eicosanoids (isoprostane [15-F(2t)-IsoP], prostaglandin-E metabolite [PGE-M], thromboxane metabolite [11dTxB(2)], prostacyclin metabolite [PGI-M]) determined by gas or liquid chromatography-mass spectrometry. RESULTS: 15-F(2t)-IsoP was higher (P=0.003), 11dTxB(2) tended to be higher (P=0.07) and PGE-M was lower (P=0.003) in females than in males. The overall median Framingham score was 4 (IQR 1-7). In multivariable analyses adjusting for age, CD4(+) T-cells, smoking status, non-steroidal anti-inflammatory drug use, aspirin use and body mass index (BMI), associations included: higher 15-F(2t)-IsoP with female sex (P=0.004) and current smoking (P=0.04), lower PGE-M with female sex (P=0.005) and higher BMI (P=0.03), higher 11dTxB(2) with increasing age (P=0.02) and current smoking (P=0.04), lower 11dTxB(2) with higher BMI (P=0.02), and higher PGI-M with current smoking (P=0.04). CONCLUSIONS: In this pilot study of predominantly virologically suppressed HIV-infected individuals on ART, there were sex-specific differences in urinary eicosanoids, with females having more risk-associated parameters despite a low Framingham score. Eicosanoids might be useful CVD biomarkers in ART-treated, HIV-infected patients. Future studies should examine eicosanoids while assessing effects of specific ART regimens and targeted interventions on CVD outcomes.

Serum leptin level mediates the association of body composition and serum C-reactive protein in HIV-infected persons on antiretroviral therapy.

Higher body mass index (BMI) is associated with increased serum C-reactive protein (CRP) levels in HIV-infected individuals on antiretroviral therapy (ART), but the relationship of adipose tissue mass to systemic inflammation is not well described in this population. We hypothesized that serum adipokine levels (i.e., hormones produced by adipocytes) are a superior predictor of CRP compared to anthropometric or radiographic measures of body composition in patients on effective, stable ART. We evaluated the relationship of serum leptin, adiponectin, and resistin, BMI, and dual energy x-ray absorptiometry (DEXA) measurements with serum highly sensitive CRP (hsCRP) in a cross-sectional cohort of 106 predominantly virologically suppressed, HIV-infected adults on ART for ≥24 weeks using multivariable linear regression and formal criteria to assess statistical mediation. Median BMI, hsCRP, and leptin values were 25.2 kg/m(2), 3.0 mg/liter, and 3.8 ng/ml, respectively. BMI and DEXA limb fat, body fat, and trunk fat measurements were significantly associated with both serum leptin and hsCRP levels (all p≤0.02). Leptin was also associated with hsCRP (p<0.01). The regression coefficient for the effect of BMI or DEXA measurements on hsCRP was reduced, and the relationship was no longer statistically significant, after adjusting for leptin, indicating leptin functioned as a mediating variable within these relationships. Adiponectin and resistin levels did not demonstrate similar effects. Serum leptin was a superior predictor of hsCRP compared to BMI and DEXA body fat measurements, which may reflect alterations in body composition in treated HIV infection and the important contribution of adipose tissue to inflammation in this population.

Enhanced PD-1 expression by T cells in cerebrospinal fluid does not reflect functional exhaustion during chronic human immunodeficiency virus type 1 infection.

During chronic viral infections, T cells are exhausted due to constant antigen exposure and are associated with enhanced programmed death 1 (PD-1) expression. Deficiencies in the PD-1/programmed death-ligand 1 (PD-L1) pathway are associated with autoimmune diseases, including those of the central nervous system (CNS). To understand the role of PD-1 expression in regulating T-cell immunity in the CNS during chronic infection, we characterized PD-1 expression in cerebrospinal fluid (CSF) and blood of individuals with chronic human immunodeficiency virus type 1 (HIV-1) infection. PD-1 expression was higher on HIV-specific CD8(+) T cells than on total CD8(+) T cells in both CSF and blood. PD-1 expression on CSF T cells correlated positively with CSF HIV-1 RNA and inversely with blood CD4(+) T-cell counts, suggesting that HIV-1 infection drives higher PD-1 expression on CSF T cells. However, in every HIV-positive individual, PD-1 expression was higher on T cells in CSF than on those in blood, despite HIV-1 RNA levels being lower. Among healthy HIV-negative controls, PD-1 expression was higher in CSF than in blood. Furthermore, frequencies of the senescence marker CD57 were lower on CSF T cells than on blood T cells, consistent with our prior observation of enhanced ex vivo functional capacity of CSF T cells. The higher PD-1 expression level on CSF T cells therefore does not reflect cellular exhaustion but may be a mechanism to downregulate immune-mediated tissue damage in the CNS. As inhibition of the PD-1/PD-L1 pathway is pursued as a therapeutic option for viral infections, potential effects of such a blockade on development of autoimmune responses in the CNS should be considered.

Clinical factors associated with plasma F2-isoprostane levels in HIV-infected adults.

PURPOSE: Oxidant stress may be an effect of antiretroviral therapy (ART) or chronic HIV infection. Plasma F2-isoprostanes (F2-IsoP) reflect lipid peroxidation and oxidant stress and have been described in ART-associated toxicities. We explored factors associated with F2-IsoP in HIV-infected adults. METHODS: HIV-infected adults enrolled in this cross-sectional study were (a) on ART including zidovudine or stavudine but not non-nucleoside reverse transcriptase inhibitors (NNRTI), (b) on ART including NNRTI, or (c) not on ART. Plasma F2-IsoP levels were quantified by GC/MS, and clinical and laboratory data were collected at enrollment. RESULTS: Among 285 participants, 24% were female, 37% were African American, and 194 (68%) were on ART; 44 (23%) of whom were receiving efavirenz, 45 (23%) nevirapine, and 85 (44%) protease inhibitors. Median F2-IsoP was lower in those on NNRTI than those on ART without NNRTI (p = .02). In a multivariable model, factors independently associated with increased F2-IsoP were female sex (p = .002), higher BMI (p = .01), and heavy smoking (p = .004). There was a trend toward lower F2-IsoP among nevirapine users (p = .054). CONCLUSIONS: Among HIV-infected adults, oxidant stress status differs by sex, BMI, smoking status, and perhaps specific ART. Prospective studies should better define relationships between oxidant stress and complications of HIV infection and its therapy.

Increased detectability of plasma HIV-1 RNA after introduction of a new assay and altered specimen-processing procedures.

After changes to assay and specimen-processing methods, plasma human immunodeficiency virus type 1 (HIV-1) RNA was frequently detectable in patients who previously had well-suppressed HIV-1 RNA levels. This artifact is attributable to shipping frozen plasma in primary plasma preparation tubes and is not caused by the HIV-1 RNA detection assay; it can be avoided by shipping plasma in a secondary tube.

Enhancement of human immunodeficiency virus (HIV)-specific CD8+ T cells in cerebrospinal fluid compared to those in blood among antiretroviral therapy-naive HIV-positive subjects.

During untreated human immunodeficiency virus type 1 (HIV-1) infection, virus-specific CD8(+) T cells partially control HIV replication in peripheral lymphoid tissues, but host mechanisms of HIV control in the central nervous system (CNS) are incompletely understood. We characterized HIV-specific CD8(+) T cells in cerebrospinal fluid (CSF) and peripheral blood among seven HIV-positive antiretroviral therapy-naïve subjects. All had grossly normal brain magnetic resonance imaging and spectroscopy and normal neuropsychometric testing. Frequencies of epitope-specific CD8(+) T cells by direct tetramer staining were on average 2.4-fold higher in CSF than in blood (P = 0.0004), while HIV RNA concentrations were lower. Cells from CSF were readily expanded ex vivo and responded to a broader range of HIV-specific human leukocyte antigen class I restricted optimal peptides than did expanded cells from blood. HIV-specific CD8(+) T cells, in contrast to total CD8(+) T cells, in CSF and blood were at comparable maturation states, as assessed by CD45RO and CCR7 staining. The strong relationship between higher T-cell frequencies and lower levels of viral antigen in CSF could be the result of increased migration to and/or preferential expansion of HIV-specific T cells within the CNS. This suggests an important role for HIV-specific CD8(+) T cells in control of intrathecal viral replication.

Implications of T-cell P-glycoprotein activity during HIV-1 infection and its therapy.

OBJECTIVES: P-glycoprotein (P-gp) may reduce antiretroviral efficacy by decreasing disposition of HIV-1 protease inhibitors into tissues and cells. In contrast, P-gp overexpression in vitro can inhibit HIV-1 replication, and some drugs induce P-gp expression. To explore which of these mechanisms predominate in vivo, this study characterized relationships between T-cell P-gp activity and clinical parameters in HIV-infected adults. METHODS: P-gp activity was quantified in total and naive CD4+ and CD8+ T cells of HIV-infected adults by flow cytometry using the substrate dye DiOC2(3). Demographic, virologic, immunologic, and treatment factors were obtained from medical records. Factors associated with P-gp activity were identified using multivariate linear regression. RESULTS: A total of 185 subjects (22% female; 34% African American) were studied, of whom 131 (71%) were receiving antiretroviral treatment. There was marked interindividual variability in P-gp activity. By multivariate analysis, higher CD4+ T-cell P-gp activity was associated with lower log10 HIV-1 RNA (P = 0.005), but not treatment or demographic factors. P-gp activity was correlated across T-cell subsets. CONCLUSIONS: The inverse relationship between P-gp activity and plasma HIV-1 RNA is most consistent with an inhibitory effect on viral replication rather than drug disposition. Antiretroviral drug class did not independently predict P-gp activity.