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Pharmacokinetic Outcomes of the Interactions of Antiretroviral Agents with Food and Supplements: A Systematic Review and Meta-Analysis. Nutrients 2022; 14:nu14030520. [PMID: 35276881 PMCID: PMC8840371 DOI: 10.3390/nu14030520] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/19/2022] [Accepted: 01/23/2022] [Indexed: 12/04/2022] Open
Abstract
Because pharmacokinetic changes in antiretroviral drugs (ARV), due to their concurrent administration with food or nutritional products, have become a clinical challenge, it is necessary to monitor the therapeutic efficacy of ARV in people living with the human immunodeficiency virus (PLWH). A systematic review and meta-analysis were conducted to clarify the pharmacokinetic outcomes of the interaction between supplements such as food, dietary supplements, and nutrients, and ARV. Twenty-four articles in both healthy subjects and PLWH were included in the qualitative analysis, of which five studies were included in the meta-analysis. Food−drug coadministration significantly increased the time to reach maximum concentration (tmax) (p < 0.00001) of ARV including abacavir, amprenavir, darunavir, emtricitabine, lamivudine, zidovudine, ritonavir, and tenofovir alafenamide. In addition, the increased maximum plasma concentration (Cmax) of ARV, such as darunavir, under fed conditions was observed. Area under the curve and terminal half-life were not significantly affected. Evaluating the pharmacokinetic aspects, it is vital to clinically investigate ARV and particular supplement interaction in PLWH. Educating patients about any potential interactions would be one of the effective recommendations during this HIV epidemic.
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Lin YS, Thummel KE, Thompson BD, Totah RA, Cho CW. Sources of Interindividual Variability. Methods Mol Biol 2021; 2342:481-550. [PMID: 34272705 DOI: 10.1007/978-1-0716-1554-6_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The efficacy, safety, and tolerability of drugs are dependent on numerous factors that influence their disposition. A dose that is efficacious and safe for one individual may result in sub-therapeutic or toxic blood concentrations in others. A significant source of this variability in drug response is drug metabolism, where differences in presystemic and systemic biotransformation efficiency result in variable degrees of systemic exposure (e.g., AUC, Cmax, and/or Cmin) following administration of a fixed dose.Interindividual differences in drug biotransformation have been studied extensively. It is recognized that both intrinsic factors (e.g., genetics, age, sex, and disease states) and extrinsic factors (e.g., diet , chemical exposures from the environment, and the microbiome) play a significant role. For drug-metabolizing enzymes, genetic variation can result in the complete absence or enhanced expression of a functional enzyme. In addition, upregulation and downregulation of gene expression, in response to an altered cellular environment, can achieve the same range of metabolic function (phenotype), but often in a less predictable and time-dependent manner. Understanding the mechanistic basis for variability in drug disposition and response is essential if we are to move beyond the era of empirical, trial-and-error dose selection and into an age of personalized medicine that will improve outcomes in maintaining health and treating disease.
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Affiliation(s)
- Yvonne S Lin
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA.
| | - Kenneth E Thummel
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Brice D Thompson
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Rheem A Totah
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Christi W Cho
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
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Rodrigues AD, Rowland A. Profiling of Drug-Metabolizing Enzymes and Transporters in Human Tissue Biopsy Samples: A Review of the Literature. J Pharmacol Exp Ther 2019; 372:308-319. [DOI: 10.1124/jpet.119.262972] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 12/19/2019] [Indexed: 12/13/2022] Open
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Alqahtani S, Bukhari I, Albassam A, Alenazi M. An update on the potential role of intestinal first-pass metabolism for the prediction of drug–drug interactions: the role of PBPK modeling. Expert Opin Drug Metab Toxicol 2018; 14:625-634. [DOI: 10.1080/17425255.2018.1482277] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Saeed Alqahtani
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
- Clinical Pharmacokinetics and Pharmacodynamics Unit, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Ishfaq Bukhari
- Department of Pharmacology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed Albassam
- Department of Clinical Pharmacy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Maha Alenazi
- Pharmacy Department, Prince Sultan Cardiac Center, Riyadh, Saudi Arabia
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Arab-Alameddine M, Décosterd LA, Buclin T, Telenti A, Csajka C. Antiretroviral drug toxicity in relation to pharmacokinetics, metabolic profile and pharmacogenetics. Expert Opin Drug Metab Toxicol 2016; 7:609-22. [PMID: 21500966 DOI: 10.1517/17425255.2011.562891] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Besides therapeutic effectiveness, drug tolerability is a key issue for treatments that must be taken indefinitely. Given the high prevalence of toxicity in HIV therapy, the factors implicated in drug-induced morbidities should be identified in order to improve the safety, tolerability and adherence to the treatments. Current approaches have focused almost exclusively on parent drug concentrations; whereas recent evidence suggests that drug metabolites resulting from complex genetic and environmental influences can also contribute to treatment outcome. Pharmacogenetic variations have shown to play a relevant role in the variability observed in antiretroviral drug exposure, clinical response and sometimes toxicity. The integration of pharmacokinetic, pharmacogenetic and metabolic determinants will more probably address current therapeutic needs in patients. AREAS COVERED This review offers a concise description of three classes of antiretroviral drugs. The review looks at the metabolic profile of these drugs and gives a comprehensive summary of the existing literature on the influence of pharmacogenetics on their pharmacokinetics and metabolic pathways, and the associated drug or metabolite toxicity. EXPERT OPINION Due to the high prevalence of toxicity and the related risk of low adherence to the treatments, association of kinetic, genetic and metabolic markers predictive of therapeutic or toxicity outcomes could represent a more complete approach for optimizing antiretroviral therapy.
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Affiliation(s)
- Mona Arab-Alameddine
- Department of Clinical Pharmacology and Toxicology, University Hospital and University of Lausanne, Beaumont, Lausanne, Switzerland
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Hernández Arroyo MJ, Cabrera Figueroa SE, Valverde Merino MP, Hurlé ADG. A pharmacist’s role in the individualization of treatment of HIV patients. Per Med 2016; 13:169-188. [DOI: 10.2217/pme.15.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pharmacological treatment of HIV is complex and varies considerably among patients, as does the response of patients to therapy, requiring treatment plans that are closely tailored to individual needs. Pharmacists can take an active role in individualizing care by employing their knowledge of pharmacokinetics and pharmacogenetics and by interacting directly with patients in counseling sessions. These strategies promote the following: maintenance of plasma concentrations of antiretroviral agents within therapeutic ranges, prediction of pharmacological response of patients with certain genetic characteristics, and clinical control of HIV through the correct use of antiretroviral treatments. Together, these strategies can be used to tailor antiretroviral therapy to individual patients, thus improving treatment efficacy and safety.
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Affiliation(s)
| | - Salvador Enrique Cabrera Figueroa
- Pharmacy Institute, University Austral of Chile, Valdivia, Chile
- Pharmacy Service, University Hospital of Salamanca, Paseo de San Vicente 58, 37007 Salamanca, Spain
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Aceti A, Gianserra L, Lambiase L, Pennica A, Teti E. Pharmacogenetics as a tool to tailor antiretroviral therapy: A review. World J Virol 2015; 4:198-208. [PMID: 26279982 PMCID: PMC4534812 DOI: 10.5501/wjv.v4.i3.198] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 01/20/2015] [Accepted: 07/27/2015] [Indexed: 02/05/2023] Open
Abstract
Highly active antiretroviral therapy (HAART) has substantially changed human immunodeficiency virus (HIV) infection from an inexorably fatal condition into a chronic disease with a longer life expectancy. This means that HIV patients should receive antiretroviral drugs lifelong, and the problems concerning with a chronic treatment (tolerability, side effects, adherence to treatment) have now become dominant. In this context, strategies for the treatment personalization have taken a central role in optimizing the therapeutic response and prevention of adverse drug reactions. In this setting, the study of pharmacogenetics features could be a very useful tool in clinical practice; moreover, nowadays the study of genetic profiles allows optimizations in the therapeutic management of People Living With HIV (PLWH) through the use of test introduced into clinical practice and approved by international guidelines for the adverse effects prevention such as the genetic test HLA-B*5701 to detect hypersensitivity to Abacavir. For other tests further studies are needed: CYP2B6 516 G > T testing may be able to identify patients at higher risk of Central Nervous System side effects following standard dosing of Efavirenz, UGT1A1*28 testing before initiation of antiretroviral therapy containing Atazanavir may aid in identifying individuals at risk of hyperbilirubinaemia. Pharmacogenetics represents a research area with great growth potential which may be useful to guide the rational use of antiretrovirals.
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Pu QH, Shi L, Yu C. Time-dependent inhibition of CYP3A4 by gallic acid in human liver microsomes and recombinant systems. Xenobiotica 2014; 45:213-7. [PMID: 25322914 DOI: 10.3109/00498254.2014.973470] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
1.Gallic acid is a main polyphenol in various fruits and plants. Inhibitory characteristics of gallic acid on CYP3A4 were still unclear. The objective of this work is hence to investigate inhibitory characteristics of gallic acid on CYP3A4 using testosterone as the probe substrate in human liver microsomes (HLMs) and recombinant CYP3A4 (rCYP3A4) systems. 2.Gallic acid caused concentration-dependent loss of CYP3A4 activity with IC50 values of 615.2 μM and 669.5 μM in HLM and rCYP3A4 systems, respectively. IC50-shift experiments showed that pre-incubation with gallic acid in the absence of NADPH contributed to 12- or 14-fold reduction of IC50 in HLM and rCYP3A4 systems, respectively, supporting a time-dependent inhibition. In HLM, time-dependent inactivation variables KI and Kinact were 485.8 μM and 0.05 min(-1), respectively. 3.Compared with the presence of NADPH, pre-incubation of gallic acid in the absence of NADPH markedly increased its inhibitory effects in HLM and rCYP3A4 systems. Those results indicate that CYP3A4 inactivation by gallic acid was independent on NADPH and was mainly mediated its oxidative products. 4.In conclusion, we showed that gallic acid weakly and time-dependently inactivated CYP3A4 via its oxidative products.
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Affiliation(s)
- Qiang-Hong Pu
- Institute of Life Science, Chongqing Medical University , Chongqing , P. R. China
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López Aspiroz E, Santos Buelga D, Cabrera Figueroa SE, Valverde Merino MDLP, Cordero Sánchez M, Domínguez-Gil Hurlé A, Carracedo Á, García Sánchez MJ. Population pharmacokinetic/pharmacogenetic model of lopinavir/ritonavir in HIV-infected patients. Per Med 2014; 11:693-704. [PMID: 29764054 DOI: 10.2217/pme.14.58] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
AIM This study aims to develop a population pharmacokinetic/pharmacogenetic model for lopinavir/ritonavir (LPV/r) in European HIV-infected patients. MATERIALS & METHODS A total of 693 LPV/r plasma concentrations were assessed and 15 single-nucleotide polymorphisms were genotyped. The population pharmacokinetic/pharmacogenetic model was created using a nonlinear mixed-effect approach (NONMEM® v.7.2.0., ICON Development Solutions, Dublin, Ireland). RESULTS Covariates significantly related to LPV/r apparent clearance (CL/F) were ritonavir trough concentration (RTC), BMI, high-density lipoprotein cholesterol (HDL-C) and certain single-nucleotide polymorphisms in genes encoding for metabolizing enzymes, which are representable as follows: CL/F = (0.216BMI + 0.0125HDL-C) × 0.713RTC × 1.26rs28371764[C/T] × 0.528rs6945984[C/C] × 0.302 CYP3A4[1461insA/del] Conclusion: The LPV/r standard dose appears to be appropriate for the rs28371764[C/T] genotype. However, lower doses should be recommended for the rs6945984[C/C] and CYP3A4[1461insA/del] genotypes and even for those patients without any of these variants, as the standard dose seems to be higher than that which is required in order to achieve therapeutic levels.
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Affiliation(s)
- Elena López Aspiroz
- Pharmacy Service, University Hospital of Salamanca, Paseo de San Vicente 58, 37007 Salamanca, Spain
| | - Dolores Santos Buelga
- Department of Pharmacy & Pharmaceutical Technology, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Salvador Enrique Cabrera Figueroa
- Pharmacy Service, University Hospital of Salamanca, Paseo de San Vicente 58, 37007 Salamanca, Spain.,Instituto de Farmacia, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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- Tormes Team: Carmen Bustos Bernal, Aurelio Fuertes Martín, María Jesús Hernández Arroyo, Alicia Iglesias Gómez and Guillermo Luna Rodrigo
| | | | - Alfonso Domínguez-Gil Hurlé
- Pharmacy Service, University Hospital of Salamanca, Paseo de San Vicente 58, 37007 Salamanca, Spain.,Department of Pharmacy & Pharmaceutical Technology, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Ángel Carracedo
- Grupo de Medicina Xenómica. Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Universidad de Santiago de Compostela, Spain.,Fundación Pública Galega de Medicina Xenómica, Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), SERGAS (Servicio Galega de Saude), Santiago de Compostela, Spain.,Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - María José García Sánchez
- Department of Pharmacy & Pharmaceutical Technology, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
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Berno G, Zaccarelli M, Gori C, Tempestilli M, Antinori A, Perno CF, Pucillo LP, D'Arrigo R. Analysis of single-nucleotide polymorphisms (SNPs) in human CYP3A4 and CYP3A5 genes: potential implications for the metabolism of HIV drugs. BMC MEDICAL GENETICS 2014; 15:76. [PMID: 24986243 PMCID: PMC4083125 DOI: 10.1186/1471-2350-15-76] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 06/25/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Drug metabolism via the cytochrome P450 (CYP450) system has emerged as an important determinant in the occurrence of several drug interactions (adverse drug reactions, reduced pharmacological effect, drug toxicities). In particular, CYP3A4 and CYP3A5 (interacting with more than 60% of licensed drugs) exhibit the most individual variations of gene expression, mostly caused by single nucleotide polymorphisms (SNPs) within the regulatory region of the CYP3A4 and CYP3A5 genes which might affect the level of enzyme production.In this study, we sought to improve the performance of sensitive screening for CYP3A polymorphism detection in twenty HIV-1 infected patients undergoing lopinavir/ritonavir (LPV/r) monotherapy. METHODS The study was performed by an effective, easy and inexpensive home-made Polymerase Chain Reaction Direct Sequencing approach for analyzing CYP3A4 and CYP3A5 genes which can detect both reported and unreported genetic variants potentially associated with altered or decreased functions of CYP3A4 and CYP3A5 proteins. Proportions and tests of association were used. RESULTS Among the genetic variants considered, CYP3A4*1B (expression of altered function) was only found in 3 patients (15%) and CYP3A5*3 (expression of splicing defect) in 3 other patients (15%). CYP3A5*3 did not appear to be associated with decreased efficacy of LPV/r in any patient, since none of the patients carrying this variant showed virological rebound during LPV/r treatment or low levels of TDM. In contrast, low-level virological rebound was observed in one patient and a low TDM level was found in another; both were carrying CYP3A4*1B. CONCLUSIONS Our method exhibited an overall efficiency of 100% (DNA amplification and sequencing in our group of patients). This may contribute to producing innovative results for better understanding the inter-genotypic variability in gene coding for CYP3A, and investigating SNPs as biological markers of individual response to drugs requiring metabolism via the cytochrome P450 system.
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Affiliation(s)
| | | | | | | | | | | | | | - Roberta D'Arrigo
- Clinical Biochemistry and Pharmacology Laboratory, National Institute for Infectious Diseases "L, Spallanzani", Via Portuense 292, Rome, 00149, Italy.
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To avoid muscle-related adverse events, choose statins carefully in patients receiving antiviral protease inhibitors. DRUGS & THERAPY PERSPECTIVES 2014. [DOI: 10.1007/s40267-014-0122-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Chauvin B, Drouot S, Barrail-Tran A, Taburet AM. Drug-drug interactions between HMG-CoA reductase inhibitors (statins) and antiviral protease inhibitors. Clin Pharmacokinet 2014; 52:815-31. [PMID: 23703578 DOI: 10.1007/s40262-013-0075-4] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The HMG-CoA reductase inhibitors are a class of drugs also known as statins. These drugs are effective and widely prescribed for the treatment of hypercholesterolemia and prevention of cardiovascular morbidity and mortality. Seven statins are currently available: atorvastatin, fluvastatin, lovastatin, pitavastatin, pravastatin, rosuvastatin and simvastatin. Although these drugs are generally well tolerated, skeletal muscle abnormalities from myalgia to severe lethal rhabdomyolysis can occur. Factors that increase statin concentrations such as drug-drug interactions can increase the risk of these adverse events. Drug-drug interactions are dependent on statins' pharmacokinetic profile: simvastatin, lovastatin and atorvastatin are metabolized through cytochrome P450 (CYP) 3A, while the metabolism of the other statins is independent of this CYP. All statins are substrate of organic anion transporter polypeptide 1B1, an uptake transporter expressed in hepatocyte membrane that may also explain some drug-drug interactions. Many HIV-infected patients have dyslipidemia and comorbidities that may require statin treatment. HIV-protease inhibitors (HIV PIs) are part of recommended antiretroviral treatment in combination with two reverse transcriptase inhibitors. All HIV PIs except nelfinavir are coadministered with a low dose of ritonavir, a potent CYP3A inhibitor to improve their pharmacokinetic properties. Cobicistat is a new potent CYP3A inhibitor that is combined with elvitegravir and will be combined with HIV-PIs in the future. The HCV-PIs boceprevir and telaprevir are both, to different extents, inhibitors of CYP3A. This review summarizes the pharmacokinetic properties of statins and PIs with emphasis on their metabolic pathways explaining clinically important drug-drug interactions. Simvastatin and lovastatin metabolized through CYP3A have the highest potency for drug-drug interaction with potent CYP3A inhibitors such as ritonavir- or cobicistat-boosted HIV-PI or the hepatitis C virus (HCV) PI, telaprevir or boceprevir, and therefore their coadministration is contraindicated. Atorvastatin is also a CYP3A substrate, but less potent drug-drug interactions have been reported with CYP3A inhibitors. Non-CYP3A-dependent statin concentrations are also affected although to a lesser extent when coadministered with HIV or HCV PIs, mainly through interaction with OATP1B1, and treatment should start with the lowest available statin dose. Effectiveness and occurrence of adverse effects should be monitored at regular time intervals.
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Affiliation(s)
- Benoit Chauvin
- Clinical Pharmacy Department, Assistance Publique Hôpitaux de Paris, Hôpital Bicêtre, Hôpitaux Universitaires Paris Sud AP/HP, 78 rue du Général Leclerc, 94270, Kremlin Bicêtre, France
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Tseng E, Walsky RL, Luzietti RA, Harris JJ, Kosa RE, Goosen TC, Zientek MA, Obach RS. Relative Contributions of Cytochrome CYP3A4 Versus CYP3A5 for CYP3A-Cleared Drugs Assessed In Vitro Using a CYP3A4-Selective Inactivator (CYP3cide). Drug Metab Dispos 2014; 42:1163-73. [DOI: 10.1124/dmd.114.057000] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Kaneko S, Yoshida S, Kanai K, Yasui-Furukori N, Iwasa H. Development of individualized medicine for epilepsy based on genetic information. Expert Rev Clin Pharmacol 2014; 1:661-81. [DOI: 10.1586/17512433.1.5.661] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Zhang X, Tierney C, Albrecht M, Demeter LM, Morse G, DiFrancesco R, Dykes C, Jiang H, Haas DW. Discordant associations between SLCO1B1 521T→C and plasma levels of ritonavir-boosted protease inhibitors in AIDS clinical trials group study A5146. Ther Drug Monit 2013; 35:209-16. [PMID: 23503447 DOI: 10.1097/ftd.0b013e318280d0ad] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Among HIV-positive patients prescribed ritonavir-boosted lopinavir, SLCO1B1 521T→C (rs4149056) is associated with increased plasma lopinavir exposure. Protease inhibitors (PIs) are also substrates for cytochrome P450 (CYP) 3A and ABCB1, which are induced by NR1I2. We characterized relationships between ABCB1, CYP3A4, CYP3A5, NR1I2, and SLCO1B1 polymorphisms and trough PI concentrations among AIDS Clinical Trials Group study A5146 participants. METHODS At study entry, subjects with virologic failure on PI-containing regimens initiated new ritonavir-boosted PI regimens. We studied associations between week 2 PI plasma trough concentrations and 143 polymorphisms in these genes, including 4 targeted polymorphisms. RESULTS Among 275 subjects with both drug concentrations and genetic data, allelic frequencies of SLCO1B1 521T→C were 15%, 1%, and 8% in whites, blacks, and Hispanics, respectively. Further analyses were limited to 268 white, black, or Hispanic subjects who initiated ritonavir-boosted lopinavir (n = 98), fosamprenavir (n = 69), or saquinavir (n = 99). Of targeted polymorphisms, SLCO1B1 521T→C tended to be associated with higher lopinavir concentrations, with a 1.38-fold increase in the mean per C allele (95% confidence interval, 0.97-1.96; n = 98; P = 0.07). With fosamprenavir, SLCO1B1 521T→C was associated with lower amprenavir concentrations, with a 35% decrease in the mean per C allele (geometric mean ratio 0.65; 95% confidence interval, 0.44-0.94; n = 69; adjusted P = 0.02). There was no significant association with saquinavir concentrations, and none of the remaining 139 exploratory polymorphisms were statistically significant after correcting for multiple comparisons. CONCLUSIONS With ritonavir-boosted PIs, a SLCO1B1 polymorphism that predicts higher lopinavir trough concentrations seems to predict lower amprenavir trough concentrations. The mechanism underlying this discordant association is uncertain.
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Affiliation(s)
- Xinyan Zhang
- Center for Biostatistics in AIDS Research, Harvard School of Public Health, Boston, Massachusetts, USA
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Zhang YP, Zuo XC, Huang ZJ, Cai JJ, Wen J, Duan DD, Yuan H. CYP3A5 polymorphism, amlodipine and hypertension. J Hum Hypertens 2013; 28:145-9. [DOI: 10.1038/jhh.2013.67] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Revised: 06/12/2013] [Accepted: 06/13/2013] [Indexed: 11/09/2022]
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Developmental Changes in the Expression and Function of Cytochrome P450 3A Isoforms: Evidence from In Vitro and In Vivo Investigations. Clin Pharmacokinet 2013; 52:333-45. [DOI: 10.1007/s40262-013-0041-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Won CS, Oberlies NH, Paine MF. Mechanisms underlying food-drug interactions: inhibition of intestinal metabolism and transport. Pharmacol Ther 2012; 136:186-201. [PMID: 22884524 DOI: 10.1016/j.pharmthera.2012.08.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 07/23/2012] [Indexed: 12/21/2022]
Abstract
Food-drug interaction studies are critical to evaluate appropriate dosing, timing, and formulation of new drug candidates. These interactions often reflect prandial-associated changes in the extent and/or rate of systemic drug exposure. Physiologic and physicochemical mechanisms underlying food effects on drug disposition are well-characterized. However, biochemical mechanisms involving drug metabolizing enzymes and transport proteins remain underexplored. Several plant-derived beverages have been shown to modulate enzymes and transporters in the intestine, leading to altered pharmacokinetic (PK) and potentially negative pharmacodynamic (PD) outcomes. Commonly consumed fruit juices, teas, and alcoholic drinks contain phytochemicals that inhibit intestinal cytochrome P450 and phase II conjugation enzymes, as well as uptake and efflux transport proteins. Whereas myriad phytochemicals have been shown to inhibit these processes in vitro, translation to the clinic has been deemed insignificant or undetermined. An overlooked prerequisite for elucidating food effects on drug PK is thorough knowledge of causative bioactive ingredients. Substantial variability in bioactive ingredient composition and activity of a given dietary substance poses a challenge in conducting robust food-drug interaction studies. This confounding factor can be addressed by identifying and characterizing specific components, which could be used as marker compounds to improve clinical trial design and quantitatively predict food effects. Interpretation and integration of data from in vitro, in vivo, and in silico studies require collaborative expertise from multiple disciplines, from botany to clinical pharmacology (i.e., plant to patient). Development of more systematic methods and guidelines is needed to address the general lack of information on examining drug-dietary substance interactions prospectively.
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Affiliation(s)
- Christina S Won
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7569, USA
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Michaud V, Bar-Magen T, Turgeon J, Flockhart D, Desta Z, Wainberg MA. The Dual Role of Pharmacogenetics in HIV Treatment: Mutations and Polymorphisms Regulating Antiretroviral Drug Resistance and Disposition. Pharmacol Rev 2012; 64:803-33. [DOI: 10.1124/pr.111.005553] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Reed K, Parissenti AM. The effect of ABCB1 genetic variants on chemotherapy response in HIV and cancer treatment. Pharmacogenomics 2012; 12:1465-83. [PMID: 22008050 DOI: 10.2217/pgs.11.84] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Despite their clearly distinct pathophysiologies, HIV and cancer are diseases whose response to chemotherapy treatment varies substantially amongst patients, in particular for those with prior drug exposure. This has been attributed, in part, to elevated expression of the ABCB1 drug transporter in some patients, which results in reduced drug accumulation in target tissues. Many mechanisms have been identified for this elevated expression of ABCB1, including variations in the sequence of the gene coding for the transporter (ABCB1). Over 50 SNPs within ABCB1 have been identified. Associations have been made between the presence of specific ABCB1 SNPs/haplotypes and both ABCB1 expression and the efficacy or toxicity of certain chemotherapy regimens. If these associations are strong and reproducibly demonstrated, then this would greatly aid in the development of individualized therapy regimes for specific cancer or HIV patients, based on their ABCB1 genotypes. This article highlights the significant recent progress made in this direction, but cautions that the utility of ABCB1 gene variants as biomarkers of chemotherapy drug response remains unclear to date.
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Affiliation(s)
- Kerry Reed
- Regional Cancer Program, Sudbury Regional Hospital, 41 Ramsey Lake Rd, Sudbury, Ontario, Canada
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CYP3A5, ABCB1, and SLCO1B1 polymorphisms and pharmacokinetics and virologic outcome of lopinavir/ritonavir in HIV-infected children. Ther Drug Monit 2012; 33:417-24. [PMID: 21743379 DOI: 10.1097/ftd.0b013e318225384f] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE CYP3A5, MDR1 (ABCB1), and OATP1 (SLCO1B1) polymorphisms have been associated with variability in the pharmacokinetics (PK) of protease inhibitors. The aim of this study was to investigate the influence of CYP3A5 A6986G, ABCB1 (C3435T and G2677T), and SLCO1B1 (T521C and A388AG) polymorphisms on the PK and virologic outcome of lopinavir/ritonavir (LPV/RTV) in HIV-infected children. DESIGN AND METHODS We conducted a prospective cohort study in children (4-18 years old) on stable antiretroviral therapy with LPV/RTV. CYP3A5, ABCB1, and SLCO1B1 genotypes were determined using polymerase chain reaction amplification with allelic discrimination assays. The 12-hour plasma area under the concentration-time curves (AUC) and clearances (CL) of LPV and RTV were estimated using noncompartmental models. HIV RNA viral load was evaluated every 12 weeks for a total study period of 52 weeks. Analysis of covariance models with adjustment for age and adherence and allometric adjustment of CL were used to assess associations between studied polymorphisms and AUC, CL, and HIV RNA. RESULTS Fifty children (median age 11.2 years) were enrolled. Allele frequencies of the genotypes studied were in Hardy-Weinberg equilibrium. There was no statistically significant association between LPV or RTV AUC or CL, and CYP3A5, ABCB1, or SLCO1B1 A388G polymorphisms. There was a significant association between SLCO1B1 T521C genotype and increased LPV AUC (P = 0.042) and a nearly significant association with decreased LPV CL (P = 0.063). None of the studied polymorphisms, including SLCO1B1 T521C, were associated with virologic outcome during 52 weeks of study follow-up. CONCLUSIONS There was no statistically significant influence of the CYP3A5, ABCB1, or SLCO1B1 A388AG polymorphisms on the PK and virologic outcome of LPV/RTV in HIV-infected children. SLCO1B1 T521C polymorphism was significantly associated with an increase in LPV AUC but was not associated with undetectable HIV RNA during the study period.
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Interplay of pharmacogenetic variations in ABCB1 transporters and cytochrome P450 enzymes. Arch Pharm Res 2011; 34:1817-28. [DOI: 10.1007/s12272-011-1104-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 08/28/2011] [Accepted: 09/05/2011] [Indexed: 01/11/2023]
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Genetically Polymorphic Cytochrome P450s and Transporters and Personalized Antimicrobial Chemotherapy. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch52] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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van Waterschoot RAB, Schinkel AH. A critical analysis of the interplay between cytochrome P450 3A and P-glycoprotein: recent insights from knockout and transgenic mice. Pharmacol Rev 2011; 63:390-410. [PMID: 21490128 DOI: 10.1124/pr.110.002584] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
CYP3A is one of the most important drug-metabolizing enzymes, determining the first-pass metabolism, oral bioavailability, and elimination of many drugs. It is also an important determinant of variable drug exposure and is involved in many drug-drug interactions. Recent studies with CYP3A knockout and transgenic mice have yielded a number of key insights that are important to consider during drug discovery and development. For instance, studies with tissue-specific CYP3A-transgenic mice have highlighted the importance of intestinal CYP3A-dependent metabolism. They also revealed that intestinal CYP3A plays an important role in the regulation of various drug-handling systems in the liver. Intestinal CYP3A activity can thus have far-reaching pharmacological effects. Besides CYP3A, the active drug efflux transporter P-glycoprotein also has a strong effect on the pharmacokinetics of numerous drugs. CYP3A and P-glycoprotein have an extensive overlap in their substrate spectrum. It has been hypothesized that for many drugs, the combined activity of CYP3A and P-glycoprotein makes for efficient intestinal first-pass metabolism of orally administered drugs as a result of a potentially synergistic collaboration. However, there is only limited in vitro and in vivo evidence for this hypothesis. There has also been some confusion in the field about what synergy actually means in this case. Our recent studies with Cyp3a/P-glycoprotein combination knockout mice have provided further insights into the CYP3A-P-glycoprotein interplay. We here present our view of the status of the synergy hypothesis and an attempt to clarify the existing confusion about synergy. We hope that this will facilitate further critical testing of the hypothesis and improve communication among researchers. Above all, the recent findings and insights into the interplay between CYP3A and P-glycoprotein may have implications for improving oral drug bioavailability and reducing adverse side effects.
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Affiliation(s)
- Robert A B van Waterschoot
- Division of Molecular Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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Barter ZE, Perrett HF, Yeo KR, Allorge D, Lennard MS, Rostami-Hodjegan A. Determination of a quantitative relationship between hepatic CYP3A5*1/*3 and CYP3A4 expression for use in the prediction of metabolic clearance in virtual populations. Biopharm Drug Dispos 2010; 31:516-32. [DOI: 10.1002/bdd.732] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Crutchley RD, Ma Q, Sulaiman A, Hochreitter J, Morse GD. Within-Patient Atazanavir Trough Concentration Monitoring in HIV-1-Infected Patients. J Pharm Pract 2010; 24:216-22. [DOI: 10.1177/0897190010380923] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Objective: Protease inhibitors (PIs) exhibit considerable interpatient pharmacokinetic variability in plasma trough concentrations. Therapeutic drug monitoring (TDM) is occasionally used to guide chronic dosing to achieve target trough concentrations, but its clinical success assumes minimal intrasubject variability. Therefore, our primary objective was to evaluate intrapatient variability in atazanavir (ATV) plasma trough concentrations in HIV-1-infected patients. Design/Methods: In a single-site, prospective, cohort study, patients on atazanavir with or without ritonavir (ATV/r or ATV) for 2 clinic visits were enrolled. Adherence and time since last dose (TSLD) were verified at each visit. ATV was assayed with high-performance liquid chromatography. Intra- and interpatient variation was evaluated using the median intraindividual percentage coefficient of variation (ICV). Results: The mean 24-hour ATV trough concentrations for the first and second visit for the ATV/r group (n = 10) was 598 (CV 84%) and 525 ng/mL (CV 66%), respectively ( P = .511), and 300 (CV 81%) and 434 ng/mL (CV 106%) for the ATV group (n = 4), respectively ( P = .369). Median ICV was 43.1% for all patients (range: 0.6%-107.6%), 38.1% (0.6%-107.6%) for the ATV/r group, and 33.1% (2.3%-87.6%) for the ATV group. Conclusions: Potential intrapatient variability in ATV troughs suggests that repeated measurements may be required to ensure that target values are maintained.
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Affiliation(s)
- Rustin D. Crutchley
- Department of Clinical Sciences and Administration, University of Houston, College of Pharmacy, Houston, TX, USA
| | - Qing Ma
- Department of Pharmacy Practice, University at Buffalo School of Pharmacy and Pharmaceutical Sciences, Buffalo, NY, USA
- Translational Pharmacology Research Core, New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY, USA
| | - Adel Sulaiman
- Immunodeficiency Services Clinic, Erie County Medical Center, Buffalo, NY, USA
- University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, NY, USA
| | - Jill Hochreitter
- Immunodeficiency Services Clinic, Erie County Medical Center, Buffalo, NY, USA
| | - Gene D. Morse
- Department of Pharmacy Practice, University at Buffalo School of Pharmacy and Pharmaceutical Sciences, Buffalo, NY, USA
- Translational Pharmacology Research Core, New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY, USA
- Immunodeficiency Services Clinic, Erie County Medical Center, Buffalo, NY, USA
- University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, NY, USA
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Weiss J, Haefeli WE. Impact of ATP-binding cassette transporters on human immunodeficiency virus therapy. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 280:219-79. [PMID: 20797684 DOI: 10.1016/s1937-6448(10)80005-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Even though potent antiretrovirals are available against human immunodeficiency virus (HIV)-1 infection, therapy fails in a significant fraction of patients. Among the most relevant reasons for treatment failure are drug toxicity and side effects, but also the development of viral resistance towards the drugs applied. Efflux by ATP-binding cassette (ABC-) transporters represents one major mechanism influencing the pharmacokinetics of antiretroviral drugs and particularly their distribution, thus modifiying the concentration within the infected cells, that is, at the site of action. Moreover, drug-drug interactions may occur at the level of these transporters and modulate their activity or expression thus influencing the efficacy and toxicity of the substrate drugs. This review summarizes current knowledge on the interaction of antiretrovirals used for HIV-1 therapy with ABC-transporters and highlights the impact of ABC-transporters for cellular resistance and therapeutic success. Moreover, the suitability of different cell models for studying the interaction of antiretrovirals with ABC-transporters is discussed.
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Affiliation(s)
- Johanna Weiss
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
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Lakhman SS, Ma Q, Morse GD. Pharmacogenomics of CYP3A: considerations for HIV treatment. Pharmacogenomics 2010; 10:1323-39. [PMID: 19663676 DOI: 10.2217/pgs.09.53] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The understanding of the cytochrome P450 3A SNP in antiretroviral therapy is important, because it is highly inducible, extremely polymorphic and metabolizes many of the drugs that are key components of highly active antiretroviral therapy regimens. This enzyme is prolific and promiscuous towards drug and xenobiotic substrate selection and it is also unpredictable among individuals, having a 5- to 20-fold variability in its ability to contribute to drug clearance. The importance of human CYP3A pharmacogenetics is also gaining attention in other established areas of pharmacotherapy as it may contribute to the goal of predicting efficacy and/or toxicity, specifically with the discovery of null allele CYP3A4*20. This review summarizes the current understanding, implications of genetic variation in the CYP3A enzymes, the central role of CYP3A in linking human genetics, the pharmacokinetics and resulting pharmacodynamic responses to certain antiretroviral drugs, and their eventual place in applied clinical pharmacotherapy.
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Affiliation(s)
- Sukhwinder S Lakhman
- Department of Pharmaceutical Sciences, DYC School of Pharmacy, Buffalo, NY 14201 USA
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Niwa T, Murayama N, Yamazaki H. Comparison of the Contributions of Cytochromes P450 3A4 and 3A5 in Drug Oxidation Rates and Substrate Inhibition. ACTA ACUST UNITED AC 2010. [DOI: 10.1248/jhs.56.239] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Toshiro Niwa
- Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University
| | - Norie Murayama
- Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University
| | - Hiroshi Yamazaki
- Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University
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Abstract
PURPOSE OF REVIEW The past year has seen the first whole genome association study for determinants of host control of HIV, as well as a number of hypothesis-driven candidate gene studies defining determinants of pharmacokinetics and toxicity of antiretroviral drugs. This review summarizes some of these findings, but it must be noted that the field is moving with unprecedented speed. RECENT FINDINGS A number of novel polymorphisms have been reported in the CYP2B6 locus that influence pharmacokinetics of non-nucleoside reverse transcriptase inhibitors. Among these are some novel nonsynonomous single nucleotide polymorphisms such as 983T > C (CYP2B6 18) and 499C > G (CYP2B6 26), as well as a partial deletion (CYP2B6 29). In addition, the concept of dose reduction according to CYP2B6 genotype has now been tested with some promising but preliminary results. Some other important advances in our knowledge have also been made, such as the association of TA repeats in the UGT1A1 regulatory region (UGT1A1 28) with atazanavir-related hyperbilirubinaemia and the association of ABCC2 and ABCC4 single nucleotide polymorphisms with tenofovir-associated renal toxicity. SUMMARY Treatment response to antiretrovirals is governed by genetic and environmental factors as well as adherence to therapy. Variability exists within pharmacological, immune and viral genes, and future studies must co-ordinate these issues.
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la Porte CJL. Saquinavir, the pioneer antiretroviral protease inhibitor. Expert Opin Drug Metab Toxicol 2009; 5:1313-22. [DOI: 10.1517/17425250903273160] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Anderson PL, Aquilante CL, Gardner EM, Predhomme J, McDaneld P, Bushman LR, Zheng JH, Ray M, MaWhinney S. Atazanavir pharmacokinetics in genetically determined CYP3A5 expressors versus non-expressors. J Antimicrob Chemother 2009; 64:1071-9. [PMID: 19710077 DOI: 10.1093/jac/dkp317] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVES The objective of this study was to compare atazanavir pharmacokinetics in genetically determined CYP3A5 expressors versus non-expressors. METHODS HIV-negative adult volunteers were pre-screened for CYP3A5 *3, *6 and *7 polymorphisms and enrollment was balanced for CYP3A5 expressor status, gender and race (African-American versus non-African-American). Participants received atazanavir 400 mg daily for 7 days followed by atazanavir/ritonavir 300 mg/100 mg daily for 7 days with pharmacokinetic studies on days 7 and 14. Other measures collected were bilirubin, UGT1A1 *28, and ABCB1 1236C > T, 2677G > T/A and 3435C > T genotypes. Data analyses utilized least squares regression. RESULTS Fifteen CYP3A5 expressors and 16 non-expressors participated. The day 7 atazanavir oral clearance (CL/F) was 1.39-fold faster (0.25 versus 0.18 L/h/kg; P = 0.045) and the C(min) was half (87 versus 171 ng/mL; P = 0.044) in CYP3A5 expressors versus non-expressors. Non-African-American CYP3A5 expressor males had 2.1-fold faster CL/F (P = 0.003) and <20% the C(min) (P = 0.0001) compared with non-African-American non-expressor males. No overall CYP3A5 expressor effects were observed during the ritonavir phase. One or two copies of wild-type ABCB1 haplotype (1236C/2677G/3435C) was predictive of slower atazanavir and ritonavir CL/F compared with zero copies (P < 0.06). Indirect bilirubin increased 1.6- to 2.8-fold more in subjects with UGT1A1 *28/*28 versus *1/*28 or *1/*1. CONCLUSIONS CYP3A5 expressors had faster atazanavir CL/F and lower C(min) than non-expressors. The effect was most pronounced in non-African-American men. Ritonavir lessened CYP3A5 expressor effects. The wild-type ABCB1 CGC haplotype was associated with slower CL/F and the UGT1A1 *28 genotype was associated with increased bilirubin. Thus, CYP3A5, ABCB1 and UGT1A1 polymorphisms are associated with atazanavir pharmacokinetics and pharmacodynamics in vivo.
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Affiliation(s)
- Peter L Anderson
- Department of Pharmaceutical Sciences, University of Colorado-Denver, Aurora, CO 80045, USA.
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Influence of CYP3A and CYP2C19 Genetic Polymorphisms on the Pharmacokinetics of Cilostazol in Healthy Subjects. Clin Pharmacol Ther 2009; 86:281-4. [DOI: 10.1038/clpt.2009.90] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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35
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van Herwaarden AE, van Waterschoot RA, Schinkel AH. How important is intestinal cytochrome P450 3A metabolism? Trends Pharmacol Sci 2009; 30:223-7. [DOI: 10.1016/j.tips.2009.02.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 02/25/2009] [Accepted: 02/25/2009] [Indexed: 10/21/2022]
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Mahungu TW, Johnson MA, Owen A, Back DJ. The impact of pharmacogenetics on HIV therapy. Int J STD AIDS 2009; 20:145-51. [DOI: 10.1258/ijsa.2008.008369] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Summary The use of highly active antiretroviral therapy in the treatment of HIV infection has resulted in significant reductions in mortality and morbidity worldwide. However, there is considerable interindividual variability in patient outcomes in terms of drug disposition, drug efficacy and adverse events. The basis of these differences is multifactorial, but host genetics are believed to play a significant part. To date, most attempts to explain this variability have focused on isolated single nucleotide polymorphisms. The most exciting development to date is the discovery of human leukocyte antigen subtype B*5701 (HLA B*5701) as a strong predictor of the abacavir hypersensitivity reaction. There is a gradual move away from single candidate gene analyses towards a high throughput whole genome approach. These studies must be performed on well characterized cohorts and reported associations must be validated in independent, ethnically diverse populations.
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Affiliation(s)
- T W Mahungu
- Department of HIV Medicine, Royal Free NHS Trust, Pond Street, London NW3 2QG
- Department of Pharmacology and Therapeutics, University of Liverpool, 70 Pembroke Place, Liverpool L69 3GF, UK
| | - M A Johnson
- Department of HIV Medicine, Royal Free NHS Trust, Pond Street, London NW3 2QG
| | - A Owen
- Department of Pharmacology and Therapeutics, University of Liverpool, 70 Pembroke Place, Liverpool L69 3GF, UK
| | - D J Back
- Department of Pharmacology and Therapeutics, University of Liverpool, 70 Pembroke Place, Liverpool L69 3GF, UK
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Ritonavir Greatly Impairs CYP3A Activity in HIV Infection With Chronic Viral Hepatitis. J Acquir Immune Defic Syndr 2008; 49:358-68. [DOI: 10.1097/qai.0b013e31818c7efe] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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van Waterschoot RAB, Rooswinkel RW, Wagenaar E, van der Kruijssen CMM, van Herwaarden AE, Schinkel AH. Intestinal cytochrome P450 3A plays an important role in the regulation of detoxifying systems in the liver. FASEB J 2008; 23:224-31. [PMID: 18794335 DOI: 10.1096/fj.08-114876] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
CYP3A4 is an important xenobiotic metabolizing enzyme. We previously found that CYP2C55 is highly up-regulated in Cyp3a(-/-) mice. Here, we have further investigated the mechanism of regulation of CYP2C55 and other detoxifying systems in Cyp3a(-/-) mice. Induction studies with prototypical inducers demonstrated an important role for the nuclear receptors PXR and CAR in the up-regulation of CYP2C55. Subsequent diet-switch experiments revealed that food-derived xenobiotics are primarily responsible for the increased induction of CYP2C55, as well as of several other primary detoxifying systems in Cyp3a(-/-) mice. Our data suggest that CYP3A normally metabolizes food-derived activators of PXR and/or CAR, explaining the increased levels of such activators in Cyp3a(-/-) mice and subsequent up-regulation of a range of detoxifying systems. Interestingly, our studies with tissue-specific CYP3A4 transgenic Cyp3a(-/-) mice revealed that not only hepatic but also intestinal expression of CYP3A4 could reduce the hepatic expression of detoxifying systems to near wild-type levels. Apparently, intestinal CYP3A4 can limit the hepatic exposure to food-derived activators of nuclear receptors, thereby regulating the expression of a range of detoxifying systems in the liver. This broad biological effect further emphasizes the importance of intestinal CYP3A activity and could have profound implications for the prediction of drug exposure.
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Affiliation(s)
- Robert A B van Waterschoot
- Division of Experimental Therapy, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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Impact of MDR1 and CYP3A5 on the oral clearance of tacrolimus and tacrolimus-related renal dysfunction in adult living-donor liver transplant patients. Pharmacogenet Genomics 2008; 18:413-23. [PMID: 18408564 DOI: 10.1097/fpc.0b013e3282f9ac01] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The potential influence of the multidrug resistance 1 (MDR1) gene and the cytochrome P450 (CYP) genes, CYP3A4 and CYP3A5, on the oral clearance (CL/F) of tacrolimus in adult living-donor liver transplant patients was examined. Furthermore, the development of renal dysfunction was analyzed in relation to the CYP3A5 genotype. METHODS Sixty de novo adult liver transplant patients receiving tacrolimus were enrolled in this study. The effects of various covariates (including intestinal and hepatic mRNA levels of MDR1 and CYP3A4, measured in each tissue taken at the time of transplantation, and the CYP3A5*3 polymorphism) on CL/F during the first 50 days after surgery were investigated with the nonlinear mixed-effects modeling program. RESULTS CL/F increased linearly until postoperative day 14, and thereafter reached a steady state. The initial CL/F immediately after liver transplantation was significantly affected by the intestinal MDR1 mRNA level (P<0.005). Furthermore, patients carrying the CYP3A5*1 allele in the native intestine, but not in the graft liver, showed a 1.47 times higher (95% confidence interval, 1.17-1.77 times, P<0.005) recovery of CL/F with time than patients having the intestinal CYP3A5*3/*3 genotype. The cumulative incidence of renal dysfunction within 1 year after transplantation, evaluated by the Kaplan-Meier method, was significantly associated with the recipient's but not donor's CYP3A5 genotype (*1/*1 and *1/*3 vs. *3/*3: recipient, 17 vs. 46%, P<0.05; donor, 35 vs. 38%, P=0.81). CONCLUSION These findings suggest that the CYP3A5*1 genotype as well as the MDR1 mRNA level in enterocytes contributes to interindividual variation in the CL/F of tacrolimus in adult recipients early after living-donor liver transplantation. Furthermore, CYP3A5 in the kidney may play a protective role in the development of tacrolimus-related nephrotoxicity.
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Freeman C, Spelman K. A critical evaluation of drug interactions withEchinaceaspp. Mol Nutr Food Res 2008; 52:789-98. [DOI: 10.1002/mnfr.200700113] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Roberts PJ, Rollins KD, Kashuba ADM, Paine MF, Nelsen AC, Williams EE, Moran C, Lamba JK, Schuetz EG, Hawke RL. The influence of CYP3A5 genotype on dexamethasone induction of CYP3A activity in African Americans. Drug Metab Dispos 2008; 36:1465-9. [PMID: 18490434 DOI: 10.1124/dmd.107.020065] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The CYP3A5(*)1 allele has been associated with differences in the metabolism of some CYP3A substrates. CYP3A5 polymorphism may also influence susceptibility for certain drug interactions. We have previously noted a correlation between basal CYP3A activity and the inductive effects of dexamethasone using the erythromycin breath test (ERBT). To determine whether CYP3A5 polymorphism influences induction of CYP3A activity, we examined the effect of an antiemetic regimen of dexamethasone, and the prototypical inducer rifampin, on the ERBT in African American volunteers prospectively stratified by CYP3A5(*)1 allele carrier status. Mean basal ERBTs were significantly higher in CYP3A5(*)1 carriers (2.71 +/- 0.53%) versus noncarriers (2.12 +/- 0.37%, P = 0.006). Rifampin increased ERBTs in CYP3A5(*)1 carriers (4.68 versus 2.60%, P = 0.0008) and noncarriers (3.55 versus 2.11%, P = 0.0017), whereas dexamethasone increased ERBTs only in CYP3A5(*)1 noncarriers (3.03 versus 2.14%, P = 0.031). CYP3A5 polymorphism appears to influence susceptibility to induction-type drug interactions for some inducers, and CYP3A5(*)1 noncarriers may be more susceptible to the inductive effects of dexamethasone as a result of lower basal CYP3A activity.
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Affiliation(s)
- Patrick J Roberts
- Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina, Chapel Hill, NC, USA
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Ma Q, Brazeau D, Forrest A, Morse GD. Advances in pharmacogenomics of antiretrovirals: an update. Pharmacogenomics 2008; 8:1169-78. [PMID: 17924832 DOI: 10.2217/14622416.8.9.1169] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Recent developments in the pharmacogenomics of antiretroviral drugs provide new prospects for predicting the efficacy of treatment and potential adverse effects. HIV/AIDS is a serious but treatable infectious disease, yet current treatment is limited by high rates of adverse drug reactions and development of resistance due to suboptimal drug concentrations in a significant proportion of patients. Antiretroviral therapy is especially suitable for pharmacogenomic investigation as both drug exposure and treatment response can be quantified and certain adverse effects can be assessed with validated measures. Additionally, there is increasing knowledge of the pharmacokinetics and dynamics of antiretroviral drugs, and some candidate genes implicated in the metabolism, transport and adverse effects have been identified. However, recent studies of the association of particular genes and their genetic variants with HIV management and adverse drug reactions have not provided unifying conclusions. This article reviews the most recently published work and summarizes the state of research in this area. Future directions for research and the application of this technology to the clinical practice of individualizing treatment for HIV management are discussed.
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Affiliation(s)
- Qing Ma
- Pharmacotherapy Research Center, University at Buffalo, Department of Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, Buffalo, NY 14260, USA.
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Katz DA, Murray B, Bhathena A, Sahelijo L. Defining drug disposition determinants: a pharmacogenetic-pharmacokinetic strategy. Nat Rev Drug Discov 2008; 7:293-305. [PMID: 18382463 DOI: 10.1038/nrd2486] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In preclinical and early clinical drug development, information about the factors influencing drug disposition is used to predict drug interaction potential, estimate and understand population pharmacokinetic variability, and select doses for clinical trials. However, both in vitro drug metabolism studies and pharmacogenetic association studies on human pharmacokinetic parameters have focused on a limited subset of the proteins involved in drug disposition. Furthermore, there has been a one-way information flow, solely using results of in vitro studies to select candidate genes for pharmacogenetic studies. Here, we propose a two-way pharmacogenetic-pharmacokinetic strategy that exploits the dramatic recent expansion in knowledge of functional genetic variation in proteins that influence drug disposition, and discuss how it could improve drug development.
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Affiliation(s)
- David A Katz
- Abbott Global Pharmaceutical Research & Development, 100 Abbott Park Road, Abbott Park, Illinois 60064-3500, USA.
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Decrease of atazanavir and lopinavir plasma concentrations in a boosted double human immunodeficiency virus protease inhibitor salvage regimen. Antimicrob Agents Chemother 2008; 52:2273-5. [PMID: 18411323 DOI: 10.1128/aac.01565-07] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human immunodeficiency virus protease inhibitor combination of atazanavir (ATV)-lopinavir-ritonavir was reported to exhibit a mutual pharmacoenhancement of plasma lopinavir and ATV concentrations which may be beneficial for salvage patients. We identified 17 patients in our pharmacokinetic database taking this combination and found conflicting results. Plasma concentrations of both ATV and lopinavir were modestly, although not significantly, decreased when the drugs were coadministered. Therefore, patients should be selected carefully for this regimen and frequent clinical and therapeutic drug monitoring is strongly advised.
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Paine MF, Widmer WW, Pusek SN, Beavers KL, Criss AB, Snyder J, Watkins PB. Further characterization of a furanocoumarin-free grapefruit juice on drug disposition: studies with cyclosporine. Am J Clin Nutr 2008; 87:863-71. [PMID: 18400708 DOI: 10.1093/ajcn/87.4.863] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND We previously established furanocoumarins as mediators of the interaction between grapefruit juice (GFJ) and the model CYP3A4 substrate felodipine in healthy volunteers using a GFJ devoid of furanocoumarins. It remains unclear whether furanocoumarins mediate drug-GFJ interactions involving CYP3A4 substrates that are also P-glycoprotein substrates. OBJECTIVE The effects of furanocoumarin-free GFJ on drug disposition were further characterized by using the dual CYP3A4/P-glycoprotein substrate cyclosporine. DESIGN By randomized crossover design, 18 healthy volunteers received cyclosporine (5 mg/kg) with 240 mL orange juice (control), GFJ, or furanocoumarin-free GFJ. Blood was collected over 24 h. Juice treatments were separated by > or = 1 wk. The effects of diluted extracts of each juice and of purified furanocoumarins on [3H]cyclosporine translocation in Caco-2 cells were then compared. RESULTS The median (range) dose-corrected cyclosporine area under the curve and the maximum concentration with GFJ (P < or = 0.007), but not with furanocoumarin-free GFJ (P > or = 0.50), were significantly higher than those with orange juice [15.6 (6.7-33.5) compared with 11.3 (4.8-22.0) x 10(-3) h/L and 3.0 (1.6-5.8) compared with 2.4 (1.1-3.1) mL(-1), respectively]. The median time to reach maximum concentration and terminal elimination half-life were not significantly different between the juices (2-3 and 7-8 h, respectively; P > or = 0.08). Relative to vehicle, the GFJ extract, orange juice extract, and purified furanocoumarins partially increased apical-to-basolateral and decreased basolateral-to-apical [3H]cyclosporine translocation in Caco-2 cells, whereas the furanocoumarin-free GFJ extract had negligible effects. Reanalysis of the clinical juices identified polymethoxyflavones as candidate P-glycoprotein inhibitors in orange juice but not in GFJ. CONCLUSIONS Furanocoumarins mediate, at least partially, the cyclosporine-GFJ interaction in vivo. A plausible mechanism involves the combined inhibition of enteric CYP3A4 and P-glycoprotein.
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Affiliation(s)
- Mary F Paine
- School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599-7360, USA.
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Pharmacogenetics and the potential for the individualization of antiretroviral therapy. Curr Opin Infect Dis 2008; 21:16-24. [PMID: 18192781 DOI: 10.1097/qco.0b013e3282f42224] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE OF REVIEW Genetic associations highlighting differences in the response to HIV infection and treatment have significantly furthered our understanding of the pathogenesis, pharmacokinetics and pharmacodynamics of antiretroviral drug action and toxicities and HIV disease itself. This review focuses on the current knowledge of associations between polymorphisms and treatment outcomes in HIV with particular emphasis on clinically relevant relationships likely to lead to the individualization of antiretroviral therapy. RECENT FINDINGS Our understanding of the immunogenetic basis of drug toxicity has been furthered by human leucocyte antigen associations with hypersensitivities for the antiretroviral drugs abacavir and nevirapine. For abacavir in particular, the use of HLA-B*5701 as a screening test appears to be generalizable across racially diverse populations and has been supported by both observational, and blinded randomized controlled trials. SUMMARY Differences in HIV acquisition and progression as well as antiretroviral efficacy and toxicity will continue to provide the basis for research to define the genetic basis of such diversity. Despite the plethora of research in this area, numerous barriers exist to the successful operationalization of genetic testing to the clinic. HLA-B*5701 screening to prevent abacavir hypersensitivity is currently the most relevant to clinical practice and highlights that the promise of cost-effective testing can be facilitated by robust laboratory methodology and quality assurance programs that can be applied to diverse treatment settings.
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Abstract
Pharmacogenetics holds promise in HIV treatment because of the complexity and potential toxicity of multidrug therapies that are prescribed for long periods. Thus far, few candidate genes have been examined for a limited number of allelic variants, but a number of confirmed associations have already emerged. A change in paradigm emerges from the availability of the HapMap, the wealth of data on less-common genetic polymorphisms, and new genotyping technology. This review presents a comprehensive analysis of the existing literature on pharmacogenetic determinants of antiretroviral drug exposure, drug toxicity, as well as genetic markers associated with the rate of disease progression. It is expected that larger-scale comprehensive genome approaches will profoundly change the landscape of knowledge in the future.
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Affiliation(s)
- A Telenti
- Institute of Microbiology, University of Lausanne, Lausanne, Switzerland.
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Effect of an antiretroviral regimen containing ritonavir boosted lopinavir on intestinal and hepatic CYP3A, CYP2D6 and P-glycoprotein in HIV-infected patients. Clin Pharmacol Ther 2008; 84:75-82. [PMID: 18183034 DOI: 10.1038/sj.clpt.6100452] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This study aimed to quantify the inhibition of cytochrome P450 (CYP3A), CYP2D6, and P-glycoprotein in human immunodeficiency virus (HIV)-infected patients receiving an antiretroviral therapy (ART) containing ritonavir boosted lopinavir, and to identify factors influencing ritonavir and lopinavir pharmacokinetics. We measured activities of CYP3A, CYP2D6, and P-glycoprotein in 28 patients before and during ART using a cocktail phenotyping approach. Activities, demographics, and genetic polymorphisms in CYP3A, CYP2D6, and P-glycoprotein were tested as covariates. Oral midazolam clearance (overall CYP3A activity) decreased to 0.19-fold (90% confidence interval (CI), 0.15-0.23), hepatic midazolam clearance and intestinal midazolam availability changed to 0.24-fold (0.20-0.29) and 1.12-fold (1.00-1.26), respectively. In CYP2D6 extensive metabolizers, the plasma ratio AUC(dextromethorphan)/AUC(dextrorphan) increased to 2.92-fold (2.31-3.69). Digoxin area under the curve (AUC)(0-12) (P-glycoprotein activity) increased to 1.81-fold (1.56-2.09). Covariates had no major influence on lopinavir and ritonavir pharmacokinetics. In conclusion, CYP3A, CYP2D6, and P-glycoprotein are profoundly inhibited in patients receiving ritonavir boosted lopinavir. The covariates investigated are not useful for a priori dose selection.
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Poonkuzhali B, Lamba J, Strom S, Sparreboom A, Thummel K, Watkins P, Schuetz E. Association of breast cancer resistance protein/ABCG2 phenotypes and novel promoter and intron 1 single nucleotide polymorphisms. Drug Metab Dispos 2008; 36:780-95. [PMID: 18180275 DOI: 10.1124/dmd.107.018366] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The hypothesis was tested that sequence diversity in breast cancer resistance protein (BCRP)'s cis-regulatory region is a significant determinant of BCRP expression. The BCRP promoter and intron 1 were resequenced in lymphoblast DNA from the polymorphism discovery resource (PDR) 44 subset. BCRP single nucleotide polymorphisms (SNPs) were genotyped in donor human livers, intestines, and lymphoblasts quantitatively phenotyped for BCRP mRNA expression. Carriers of the -15622C>T SNP had lower BCRP expression in multiple tissues. The intron 1 SNP 16702C>T was associated with high expression in livers; 1143G>A was associated with low expression in intestine; 12283T>C was associated with higher expression in the PDR44 and White livers. The -15994C>T promoter SNP was significantly associated with higher BCRP expression in multiple tissues. Patients with the -15994C>T genotype had substantially higher clearance of p.o. imatinib. We next determined whether BCRP expression was related to polymorphic alternative splicing or alternative promoter use. Liver polymorphically expressed an alternatively spliced mRNA [splice variant (SV) 1] skipping exon 2. Although SV1+ livers did not uniformly carry the exon 2 G34A allele, 90% of G34A livers expressed SV1 (versus 4% of 34GG livers). BCRP mRNA was significantly lower among Hispanic livers with the G34A variant genotype and may be due, in part, to polymorphic exon 2 splicing. Analysis of allele expression imbalance (AEI) showed that PDR44 samples with AEI had lower BCRP mRNA expression; however, no linked cis-polymorphisms were identified. BCRP used multiple promoters, and livers differentially using alternative exon 1b had lower BCRP. In conclusion, BCRP expression in lymphoblasts, liver, and intestine is associated with novel promoter and intron 1 SNPs.
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Ma Q, Brazeau D, Zingman BS, Reichman RC, Fischl MA, Gripshover BM, Venuto CS, Slish JC, DiFrancesco R, Forrest A, Morse GD. Multidrug resistance 1 polymorphisms and trough concentrations of atazanavir and lopinavir in patients with HIV. Pharmacogenomics 2007; 8:227-35. [PMID: 17324111 DOI: 10.2217/14622416.8.3.227] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
INTRODUCTION HIV-infected patients receiving protease inhibitors may benefit from therapeutic drug monitoring-assisted dose adjustment to achieve target plasma concentrations. However, efflux pumps such as permeability-glycoprotein, which is encoded by the multidrug resistance (MDR)1 gene, may decrease intracellular drug concentrations, thus reducing the amount of drug at the site of action. Plasma concentrations of protease inhibitors and CD4 cell count response have been associated with the T allele at the MDR1 C3435T locus. We examined MDR1 single nucleotide polymorphisms in a cohort of patients in whom therapeutic drug monitoring is ongoing through a research protocol. METHODS In a multicenter study, genotypic analyses at two MDR1 loci, C3435T and G2677T, were performed by a real-time polymerase chain reaction method using DNA from 103 patients categorized as substance users or nonusers on atazanavir or lopinavir as the primary antiretrovirals. Allelic frequencies were determined as a function of racial/ethnic background, substance use status and trough concentrations of atazanavir and lopinavir. RESULTS The C/T and G/T alleles at the MDR1 C3435T and G2677T loci were equally frequent in the Caucasian population, but the wild-type alleles were more prevalent in the African-American population (59% homozygous [CC] and 32% heterozygous [CT] for C3435T; 80% homozygous [GG] and 16% heterozygous [GT] for G2677T). The frequencies in the Hispanic population were 46% CC and 38% CT for C3435T, and 58% GG and 38% GT for G2677T. No significant differences were seen in allele frequencies for MDR1 polymorphisms in substance user versus nonuser groups. Trough plasma concentrations of atazanavir or lopinavir were not correlated with the variant T allele. CONCLUSIONS These data confirm the higher prevalence of wild-type alleles of the MDR1 gene in African-Americans and the linkage disequilibrium between C3435T and G2677T loci. The T allele at the MDR1 C3435T and G2677T loci was not associated with higher atazanavir or lopinavir trough concentrations.
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Affiliation(s)
- Qing Ma
- University at Buffalo, Pharmacotherapy Research Center, School of Pharmacy and Pharmaceutical Sciences, NY, USA.
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