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Tanner JA, Tyndale RF. Variation in CYP2A6 Activity and Personalized Medicine. J Pers Med 2017; 7:jpm7040018. [PMID: 29194389 PMCID: PMC5748630 DOI: 10.3390/jpm7040018] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/17/2017] [Accepted: 11/27/2017] [Indexed: 12/16/2022] Open
Abstract
The cytochrome P450 2A6 (CYP2A6) enzyme metabolizes several clinically relevant substrates, including nicotine-the primary psychoactive component in cigarette smoke. The gene that encodes the CYP2A6 enzyme is highly polymorphic, resulting in extensive interindividual variation in CYP2A6 enzyme activity and the rate of metabolism of nicotine and other CYP2A6 substrates including cotinine, tegafur, letrozole, efavirenz, valproic acid, pilocarpine, artemisinin, artesunate, SM-12502, caffeine, and tyrosol. CYP2A6 expression and activity are also impacted by non-genetic factors, including induction or inhibition by pharmacological, endogenous, and dietary substances, as well as age-related changes, or interactions with other hepatic enzymes, co-enzymes, and co-factors. As variation in CYP2A6 activity is associated with smoking behavior, smoking cessation, tobacco-related lung cancer risk, and with altered metabolism and resulting clinical responses for several therapeutics, CYP2A6 expression and enzyme activity is an important clinical consideration. This review will discuss sources of variation in CYP2A6 enzyme activity, with a focus on the impact of CYP2A6 genetic variation on metabolism of the CYP2A6 substrates.
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Affiliation(s)
- Julie-Anne Tanner
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Rachel F Tyndale
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada.
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Brief Report: Late Efavirenz-Induced Ataxia and Encephalopathy: A Case Series. J Acquir Immune Defic Syndr 2017; 75:577-579. [PMID: 28520619 DOI: 10.1097/qai.0000000000001451] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND WHO treatment guidelines recommend efavirenz in first-line antiretroviral therapy (ART). Efavirenz commonly causes early transient neuropsychiatric adverse events. We present 20 cases with severe encephalopathy accompanied by ataxia due to efavirenz toxicity. METHODS Consecutive HIV-infected adults taking efavirenz-containing ART admitted to Tshepong hospital, Klerksdorp, South Africa with ataxia and encephalopathy were included in this case series. RESULTS We identified 20 women admitted to hospital with severe ataxia. All received efavirenz-based ART for a median of 2 years. All had severe ataxia and none had nystagmus. Eleven had features of encephalopathy. Median weight was 34 kg [interquartile range (IQR): 29.7-35.3]; median CD4 count 299 cells/mm (IQR: 258-300) and most (18 of 19) were virally suppressed. Eight patients had a record of prior weights and 7 of 8 showed significant weight loss with a median weight loss of 10.8 kg (IQR: 8-11.6). All cases had plasma efavirenz assays, 19 were supratherapeutic (more than twice the upper level of therapeutic range), and 15 had concentrations above the upper limit of assay detection. Ataxia resolved after withdrawal of efavirenz at a median time of 2 months (IQR: 1.25-4) and recurred in 2 of 3 patients when rechallenged. Admissions before diagnosis were frequent with 10 cases admitted previously. Three women died. CONCLUSIONS Efavirenz toxicity may present with severe reversible ataxia often with encephalopathy years after its initiation, likely in genetic slow metabolizers. We recommend that patients whose weight is <40 kg receive lower doses of efavirenz and that therapeutic drug monitoring be considered, and efavirenz stopped in patients presenting with ataxia. Eight patients had a record of prior subsequent weights and 7 of 8 showed significant weight loss gain; median gain of 10.8 kg (IQR: 8-11.6).
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Soeria-Atmadja S, Österberg E, Gustafsson LL, Dahl ML, Eriksen J, Rubin J, Navér L. Genetic variants in CYP2B6 and CYP2A6 explain interindividual variation in efavirenz plasma concentrations of HIV-infected children with diverse ethnic origin. PLoS One 2017; 12:e0181316. [PMID: 28886044 PMCID: PMC5590735 DOI: 10.1371/journal.pone.0181316] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 06/29/2017] [Indexed: 12/13/2022] Open
Abstract
Background Approximately 2.6 million children live with HIV globally, and efavirenz (EFV) is one of the most widely used antiretroviral agents for HIV treatment in children and adults. There are concerns about the appropriateness of current EFV dosing and it has been discussed whether EFV dosing should be adapted according to genotype in children as suggested for adults. Aim To investigate if pediatric EFV dosing should be guided by genetic variation in drug metabolizing enzymes rather than by body weight. Method EFV plasma concentrations measured for clinical purposes from all children less than 18 years old at Karolinska University Hospital, Stockholm, Sweden, treated with EFV were collected retrospectively. They were genotyped for eleven polymorphisms in genes coding for drug-metabolizing enzymes and P-glycoprotein, of potential importance for EFV disposition. Data on country of origin, sex, age, weight, HIV RNA, viral resistance patterns, CD4 cells, adherence to treatment, subjective health status and adverse events were collected from their medical records. Results Thirty-six patients and 182 (mean 5 samples/patient) EFV plasma concentration measurements from children of African, Asian and Latin American origin were included. EFV plasma concentration varied 21-fold between measurements (n = 182) (0.85–19.3 mg/L) and 9-fold measured as mean EFV plasma concentration across the subjects (1.55–13.4 mg/L). A multivariate mixed-effects restricted maximum likelihood regression model, including multiple gene polymorphisms, identified CYP2B6*6 T/T (p < 0.0005), CYP2B6*11 G/G (p < 0.0005), CYP2A6*9 A/C (p = 0.001) genotypes, age at treatment initiation (p = 0.002) and time from treatment initiation (p < 0.0005) as independent factors significantly related to loge concentration/(dose/weight). The contribution of the model to the intra- and interindividual variation were 6 and 75%, respectively (Bryk/Raudenbush R-squared level). Conclusion Genetic polymorphisms in CYP2B6 and CYP2A6 explained a significant proportion of variability in EFV plasma concentration in HIV-infected children in a multi-ethnic outpatient clinic. Knowledge about individual variants in key drug metabolizing enzyme genes could improve clinical safety and genotype directed dosing could achieve more predictable EFV plasma concentrations in HIV-infected children.
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Affiliation(s)
- Sandra Soeria-Atmadja
- Department of Pediatrics, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm, Sweden
| | - Emma Österberg
- Department of Pediatrics, Karolinska University Hospital, Stockholm, Sweden
| | - Lars L Gustafsson
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Marja-Liisa Dahl
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Jaran Eriksen
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Johanna Rubin
- Department of Pediatrics, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm, Sweden
| | - Lars Navér
- Department of Pediatrics, Karolinska University Hospital, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm, Sweden
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54
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Medeiros RMD, Menti CF, Benelli JL, Matte MCC, Melo MGD, Almeida SEDM, Fiegenbaum M. Association of NR1I2 gene polymorphisms and time of progression to AIDS. Mem Inst Oswaldo Cruz 2017; 112:269-274. [PMID: 28327790 PMCID: PMC5354613 DOI: 10.1590/0074-02760160382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 12/27/2016] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The time of progression towards AIDS can vary greatly among seropositive patients, and may be associated with host genetic variation. The NR1I2 (PXR) gene, a ligand-activated transcription factor, regulates the transcription immune pathway genes and can therefore be targets of viral replication mechanisms influencing time of progression to AIDS. OBJECTIVE To verify the association of single nucleotide polymorphisms (SNPs) rs3814057, rs6785049, rs7643645, and rs2461817 in the NR1I2 (PXR) gene with progression to AIDS in HIV-1 infected patients. METHODS Blood samples were obtained from 96 HIV-1 positive individuals following informed consent. DNA was isolated and genotyped through real time polymerase chain reaction (PCR) for the presence of SNPs in the NR1I2. Questionnaires on socio-demographic features and behaviors were answered and time of progression to AIDS was estimated based on medical chart analysis. FINDINGS Patients with the GG genotype for rs7643645 were shown to be related with a more rapid disease progression when compared to GA and AA genotypes. This result was maintained by the Multivariate Cox Regression considering sex, ethnicity, and presence of HLA-B*57, HLA-B*27, and CCR5del32 polymorphisms. MAIN CONCLUSIONS Recent studies reported the expression of the nuclear receptors in T-Lymphocytes, suggesting their possible role in the immune response. In addition, nuclear receptors have been shown to inhibit the HIV replication, although no such mechanism has been thoroughly elucidated to date. This is the first time an association between NR1I2 polymorphism and time of progression to AIDS is reported and supports an apparent relationship between the gene in the immune response and identifies another genetic factor influencing AIDS progression.
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Affiliation(s)
- Rúbia Marília de Medeiros
- Fundação Estadual de Produção e Pesquisa, Centro de Desenvolvimento Científico e Tecnológicos, Porto Alegre, RS, Brasil.,Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brasil
| | - Carolina Fialho Menti
- Universidade Federal de Ciências da Saúde de Porto Alegre, Faculdade de Biomedicina, Porto Alegre, RS, Brasil
| | - Jéssica Louise Benelli
- Universidade Federal de Ciências da Saúde de Porto Alegre, Programa de Pós-Graduação em Patologia, Porto Alegre, RS, Brasil
| | - Maria Cristina Cotta Matte
- Fundação Estadual de Produção e Pesquisa, Centro de Desenvolvimento Científico e Tecnológicos, Porto Alegre, RS, Brasil.,Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brasil
| | | | - Sabrina Esteves de Matos Almeida
- Fundação Estadual de Produção e Pesquisa, Centro de Desenvolvimento Científico e Tecnológicos, Porto Alegre, RS, Brasil.,Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brasil.,Universidade Feevale, Novo Hamburgo, Brasil
| | - Marilu Fiegenbaum
- Universidade Federal de Ciências da Saúde de Porto Alegre, Programa de Pós-Graduação em Patologia, Porto Alegre, RS, Brasil
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55
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Gallien S, Journot V, Loriot MA, Sauvageon H, Morlat P, Reynes J, Reliquet V, Chêne G, Molina JM. Cytochrome 2B6 polymorphism and efavirenz-induced central nervous system symptoms : a substudy of the ANRS ALIZE trial. HIV Med 2017; 18:537-545. [PMID: 28145050 DOI: 10.1111/hiv.12488] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2016] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Single nucleotide polymorphisms in the cytochrome P450 (CYP) 2B6 gene have been associated with high interindividual variation in efavirenz pharmacokinetics. However, clinical data on the relationship of CYP2B6 polymorphisms with the occurrence of efavirenz-induced central nervous system (CNS) symptoms are limited. METHODS We analysed four polymorphisms in the CYP2B6 (516 G>T), CYP3A5 (6986 A>G) and ATP-binding cassette, sub-family B, member 1 (ABCB1) (2677 G>T/A and 3435 C>T) genes in HIV-infected adults virologically suppressed on a protease inhibitor-based regimen who switched to a regimen containing emtricitabine, didanosine and efavirenz in the setting of the ANRS ALIZE trial. Kaplan-Meier methods and Cox regression analysis were used to investigate their association with efavirenz plasma levels and CNS events up to 48 months after switching. RESULTS In total, 191 patients with a median age of 41 years, who were 87% male and 85% Caucasian, were enrolled in the study. Variant allelic frequencies were 0.49, 0.93, 0.59 and 0.63 for CYP2B6 516, CYP3A5 392, ABCB1 2677 and ABCB1 3435, respectively. The median efavirenz plasma concentration (MEPC) was 2.2 mg/L [interquartile range (IQR) 1.7-2.8 mg/L] and was significantly higher in patients with the deficient CYP2B6 516T. Overall, 242 CNS events were reported in 104 individuals (54%). No correlation was found between MEPC and CNS events. The occurrence of a first CNS event was lower in patients with the CYP2B6 516 G/G genotype vs. CYP2B6 516 T genotypes [50% (IQR: 40-60%) vs. 66% (IQR: 56-75%), respectively; P = 0.02]. In an adjusted Cox regression model, there was a tendency towards a higher risk of a first CNS event among carriers of the variant CYP2B6 516 T allele (relative risk 1.4 [95% CI, 0.99-2.1]; P?=?.06), compared with noncarriers. CONCLUSIONS The deficient CYP2B6 516 T allele is associated with higher efavirenz plasma drug levels and more frequent CNS-related symptoms.
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Affiliation(s)
- S Gallien
- Sorbonne Paris Cité, Université Paris Diderot Paris 7, Paris, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Service de Maladies Infectieuses, Hôpital Saint-Louis, Paris, France
| | | | - M-A Loriot
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,INSERM UMR_S1147, Centre Universitaire des Saints-Pères, Paris, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Service de Biochimie, Hôpital Européen Georges Pompidou, Paris, France
| | - H Sauvageon
- Assistance Publique-Hôpitaux de Paris (AP-HP), Pharmacie, Hôpital Saint-Louis, Paris, France
| | - P Morlat
- Service de médecine interne, Hôpital Saint-André, Bordeaux, France
| | - J Reynes
- Département des Maladies Infectieuses et Tropicales, Centre Hospitalier Universitaire Montpellier, Montpellier, France
| | - V Reliquet
- Service de Maladies Infectieuses, CHU Nantes, Nantes, France
| | - G Chêne
- INSERM U1219, Bordeaux, France
| | - J-M Molina
- Sorbonne Paris Cité, Université Paris Diderot Paris 7, Paris, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Service de Maladies Infectieuses, Hôpital Saint-Louis, Paris, France
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56
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Pharmacokinetic, Pharmacogenetic, and Other Factors Influencing CNS Penetration of Antiretrovirals. AIDS Res Treat 2016; 2016:2587094. [PMID: 27777797 PMCID: PMC5061948 DOI: 10.1155/2016/2587094] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/21/2016] [Indexed: 12/22/2022] Open
Abstract
Neurological complications associated with the human immunodeficiency virus (HIV) are a matter of great concern. While antiretroviral (ARV) drugs are the cornerstone of HIV treatment and typically produce neurological benefit, some ARV drugs have limited CNS penetration while others have been associated with neurotoxicity. CNS penetration is a function of several factors including sieving role of blood-brain and blood-CSF barriers and activity of innate drug transporters. Other factors are related to pharmacokinetics and pharmacogenetics of the specific ARV agent or mediated by drug interactions, local inflammation, and blood flow. In this review, we provide an overview of the various factors influencing CNS penetration of ARV drugs with an emphasis on those commonly used in sub-Saharan Africa. We also summarize some key associations between ARV drug penetration, CNS efficacy, and neurotoxicity.
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57
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Evans J, Swart M, Soko N, Wonkam A, Huzair F, Dandara C. A Global Health Diagnostic for Personalized Medicine in Resource-Constrained World Settings: A Simple PCR-RFLP Method for Genotyping CYP2B6 g.15582C>T and Science and Policy Relevance for Optimal Use of Antiretroviral Drug Efavirenz. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2016; 19:332-8. [PMID: 26415139 DOI: 10.1089/omi.2015.0039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The use of pharmacogenomics (PGx) knowledge in treatment of individual patients is becoming a common phenomenon in the developed world. However, poorly resourced countries have thus far been constrained for three main reasons. First, the cost of whole genome sequencing is still considerably high in comparison to other (non-genomics) diagnostics in the developing world where both science and social dynamics create a dynamic and fragile healthcare ecosystem. Second, studies correlating genomic differences with drug pharmacokinetics and pharmacodynamics have not been consistent, and more importantly, often not indexed to impact on societal end-points, beyond clinical practice. Third, ethics regulatory frames over PGx testing require improvements based on nested accountability systems and in ways that address the user community needs. Thus, CYP2B6 is a crucial enzyme in the metabolism of antiretroviral drugs, efavirenz and nevirapine. More than 40 genetic variants have been reported, but only a few contribute to differences in plasma EFV and NVP concentrations. The most widely reported CYP2B6 variants affecting plasma drug levels include c.516G>T, c.983T>C, and to a lesser extent, g.15582C>T, which should be considered in future PGx tests. While the first two variants are easily characterized, the g.15582C>T detection has been performed primarily by sequencing, which is costly, labor intensive, and requires access to barely available expertise in the developing world. We report here on a simple, practical PCR-RFLP method with vast potentials for use in resource-constrained world regions to detect the g.15582C>T variation among South African and Cameroonian persons. The effects of CYP2B6 g.15582C>T on plasma EFV concentration were further evaluated among HIV/AIDS patients. We report no differences in the frequency of the g.15582T variant between the South African (0.08) and Cameroonian (0.06) groups, which are significantly lower than reported in Asians (0.39) and Caucasians (0.31). The g.15582C/T and T/T genotypes were associated with significantly reduced EFV levels (p=0.006). This article additionally presents the policy relevance of the PGX global health diagnostics and therefore, collectively makes an original interdisciplinary contribution to the field of integrative biology and personalized medicine in developing world. Such studies are, in fact, broadly important because resource-constrained regions exist not only in developing world but also in major geographical parts of the G20 nations and the developed countries.
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Affiliation(s)
- Jonathan Evans
- 1 Pharmacogenetics and Cancer Research Group, Division of Human Genetics, Department of Clinical Laboratory Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town , Cape Town, South Africa
| | - Marelize Swart
- 1 Pharmacogenetics and Cancer Research Group, Division of Human Genetics, Department of Clinical Laboratory Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town , Cape Town, South Africa
| | - Nyarai Soko
- 1 Pharmacogenetics and Cancer Research Group, Division of Human Genetics, Department of Clinical Laboratory Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town , Cape Town, South Africa
| | - Ambroise Wonkam
- 1 Pharmacogenetics and Cancer Research Group, Division of Human Genetics, Department of Clinical Laboratory Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town , Cape Town, South Africa
| | - Farah Huzair
- 2 Science, Technology and Innovation Studies, School of Social and Political Science, University of Edinburgh , Edinburgh, United Kingdom
| | - Collet Dandara
- 1 Pharmacogenetics and Cancer Research Group, Division of Human Genetics, Department of Clinical Laboratory Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town , Cape Town, South Africa
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Röhrich CR, Drögemöller BI, Ikediobi O, van der Merwe L, Grobbelaar N, Wright GE, McGregor N, Warnich L. CYP2B6*6 and CYP2B6*18 Predict Long-Term Efavirenz Exposure Measured in Hair Samples in HIV-Positive South African Women. AIDS Res Hum Retroviruses 2016; 32:529-38. [PMID: 26655325 DOI: 10.1089/aid.2015.0048] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Long-term exposure to efavirenz (EFV) measured in hair samples may predict response to antiretroviral treatment (ART). Polymorphisms in CYP2B6 are known to alter EFV levels. The aim of this study was to assess the relationship between CYP2B6 genotype, EFV levels measured in hair, and virological outcomes on ART in a real-world setting. We measured EFV levels in hair from HIV-positive South African females who had been receiving EFV-based treatment for at least 3 months from the South African Black (SAB) (n = 81) and Cape Mixed Ancestry (CMA) (n = 53) populations. Common genetic variation in CYP2B6 was determined in 15 individuals from each population using bidirectional Sanger sequencing. Prioritized variants (n = 16) were subsequently genotyped in the entire patient cohort (n = 134). The predictive value of EFV levels in hair and selected variants in CYP2B6 on virological treatment outcomes was assessed. Previously described alleles (CYP2B6*2, CYP2B6*5, CYP2B6*6, CYP2B6*17, and CYP2B6*18), as well as two novel alleles (CYP2B6*31 and CYP2B6*32), were detected in this study. Compared to noncarriers, individuals homozygous for CYP2B6*6 had ∼109% increased EFV levels in hair (p = .016) and CYP2B6*18 heterozygotes demonstrated 82% higher EFV hair levels (p = .0006). This study confirmed that alleles affecting CYP2B6 metabolism and subsequent EFV exposure are present at significant frequencies in both the SAB and CMA populations. Furthermore, this study demonstrated that the use of hair samples for testing EFV concentrations may be a useful tool in determining long-term drug exposure in resource-limited countries.
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Affiliation(s)
- Carola R. Röhrich
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
| | | | - Ogechi Ikediobi
- Departments of Pharmacy, University of California San Francisco, UCSF, San Francisco, California
| | - Lize van der Merwe
- Department of Molecular Biology and Human Genetics, Stellenbosch University, Tygerberg, South Africa
- Department of Statistics, University of Western Cape, Bellville, South Africa
| | | | - Galen E.B. Wright
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
| | - Nathaniel McGregor
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
- Department of Psychiatry, Stellenbosch University, Tygerberg, South Africa
| | - Louise Warnich
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
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59
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Orrell C, Bienczak A, Cohen K, Bangsberg D, Wood R, Maartens G, Denti P. Effect of mid-dose efavirenz concentrations and CYP2B6 genotype on viral suppression in patients on first-line antiretroviral therapy. Int J Antimicrob Agents 2016; 47:466-72. [PMID: 27211824 DOI: 10.1016/j.ijantimicag.2016.03.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/14/2016] [Accepted: 03/28/2016] [Indexed: 01/11/2023]
Abstract
The therapeutic range for efavirenz plasma concentrations is unclear and some studies found no correlation with viral non-suppression. Efavirenz concentrations are variable, driven in part by polymorphisms in CYP2B6. We hypothesised that efavirenz mid-dosing concentrations, together with CYP2B6 metaboliser genotype, could predict viral non-suppression. Participants starting first-line efavirenz-based antiretroviral therapy were monitored for 48 weeks. HIV-RNA and efavirenz mid-dose interval concentrations were determined at Weeks 16 and 48. CYP2B6 metaboliser genotype status was determined by 516G→T and 983T→C polymorphisms. Cox proportional hazards modelling was used to predict viral non-suppression and to determine the most predictive efavirenz mid-dosing concentration threshold. In total, 180 participants were included. Median efavirenz concentrations were 2.3 mg/L (IQR 1.6-4.6 mg/L) and 2.2 mg/L (IQR 1.5-3.9 mg/L) at Weeks 16 and 48, respectively. Moreover, 49 (27.2%), 84 (46.7%) and 39 (21.7%) participants had extensive, intermediate or slow CYP2B6 metaboliser genotype, respectively. Log2 efavirenz concentrations [adjusted hazard ratio (aHR) = 0.77, 95% CI 0.67-0.89] and baseline CD4 cell count (aHR = 0.994, 95% CI 0.989-0.998), but not CYP2B6 genotype, were predictive of viral non-suppression. For every doubling of efavirenz concentration there was a 23% decrease in the hazard of non-suppression. A threshold of 0.7 mg/L was found to be the efavirenz mid-dosing concentration that was most predictive of non-suppression. Mid-dosing efavirenz concentrations are predictive of viral non-suppression, but the currently recommended lower therapeutic limit (1 mg/L) is higher than our finding. Knowledge of CYP2B6 metaboliser genotype is not required for prediction of virological outcomes.
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Affiliation(s)
- Catherine Orrell
- Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine and Department of Medicine, University of Cape Town, Cape Town, South Africa.
| | - Andrzej Bienczak
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Karen Cohen
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - David Bangsberg
- Harvard Medical School, Boston, MA, USA; Massachusetts General Hospital Center for Global Health, Boston, MA, USA; Ragon Institute of Massachusetts General Hospital, Boston, MA, USA
| | - Robin Wood
- Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine and Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Gary Maartens
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Paolo Denti
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
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60
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Bienczak A, Cook A, Wiesner L, Olagunju A, Mulenga V, Kityo C, Kekitiinwa A, Owen A, Walker AS, Gibb DM, McIlleron H, Burger D, Denti P. The impact of genetic polymorphisms on the pharmacokinetics of efavirenz in African children. Br J Clin Pharmacol 2016; 82:185-98. [PMID: 26991336 PMCID: PMC4917805 DOI: 10.1111/bcp.12934] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/07/2016] [Accepted: 03/10/2016] [Indexed: 01/11/2023] Open
Abstract
Aims Using a model‐based approach, the efavirenz steady‐state pharmacokinetics in African children is characterized, quantifying demographic and genotypic effects on the drug's disposition. Simulations are also conducted allowing prediction of optimized doses of efavirenz in this population. Methods We modelled the steady‐state population pharmacokinetics of efavirenz in Ugandan and Zambian children using nonlinear mixed‐effects modelling. Individual mid‐dose efavirenz concentrations were derived and simulations explored genotype‐based dose optimization strategies. Results A two‐compartment model with absorption through transit compartments well described 2086 concentration‐time points in 169 children. The combined effect of single nucleotide polymorphisms (SNPs) 516G>T and 983T>C explained 44.5% and 14.7% of the variability in efavirenz clearance and bioavailability, respectively. The detected frequencies of composite CYP2B6 genotype were 0.33 for 516GG|983TT, 0.35 for 516GT|983TT, 0.06 for 516GG|983TC, 0.18 for 516TT|983TT, 0.07 516GT|983TC and 0.01 for 516GG|983CC. The corresponding estimated clearance rates were 6.94, 4.90, 3.93, 1.92, 1.36, and 0.74 l h−1 for a 15.4 kg child and median (95% CI) observed mid‐dose concentrations 1.55 (0.51–2.94), 2.20 (0.97–4.40), 2.03 (1.19–4.53), 7.55 (2.40–14.74), 7.79 (3.66–24.59) and 18.22 (11.84–22.76) mg l−1, respectively. Simulations showed that wild‐type individuals had exposures at the bottom of therapeutic range, while slower metabolizers were overexposed. Conclusions Dosage guidelines for African children should take into consideration the combined effect of SNPs CYP2B6 516G>T and 983T>C.
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Affiliation(s)
- Andrzej Bienczak
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Adrian Cook
- MRC Clinical Trials Unit at University College London, London, UK
| | - Lubbe Wiesner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Adeniyi Olagunju
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Veronica Mulenga
- University Teaching Hospital, Department of Paediatrics and Child Health, Lusaka, Zambia
| | - Cissy Kityo
- Joint Clinical Research Centre, Kampala, Uganda
| | - Addy Kekitiinwa
- Baylor College of Medicine Bristol Myers Squibb Children's Clinical Centre of Excellence, Kampala, Uganda / Gulu Regional Centre of Excellence, Gulu, Uganda
| | - Andrew Owen
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - A Sarah Walker
- MRC Clinical Trials Unit at University College London, London, UK
| | - Diana M Gibb
- MRC Clinical Trials Unit at University College London, London, UK
| | - Helen McIlleron
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - David Burger
- Department of Pharmacy, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Paolo Denti
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
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Kim MH, Zhou A, Mazenga A, Ahmed S, Markham C, Zomba G, Simon K, Kazembe PN, Abrams EJ. Why Did I Stop? Barriers and Facilitators to Uptake and Adherence to ART in Option B+ HIV Care in Lilongwe, Malawi. PLoS One 2016; 11:e0149527. [PMID: 26901563 PMCID: PMC4762691 DOI: 10.1371/journal.pone.0149527] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 02/02/2016] [Indexed: 01/11/2023] Open
Abstract
Causes for loss-to-follow-up, including early refusals of and stopping antiretroviral therapy (ART), in Malawi's Option B+ program are poorly understood. This study examines the main barriers and facilitators to uptake and adherence to ART under Option B+. In depth interviews were conducted with HIV-infected women who were pregnant or postpartum in Lilongwe, Malawi (N = 65). Study participants included women who refused ART initiation (N = 10), initiated ART and then stopped (N = 26), and those who initiated ART and remained on treatment (N = 29). The barriers to ART initiation were varied and included concerns about partner support, feeling healthy, and needing time to think. The main reasons for stopping ART included side effects and lack of partner support. A substantial number of women started ART after initially refusing or stopping ART. There were several facilitators for re-starting ART, including encouragement from community health workers, side effects subsiding, decline in health, change in partner, and fear of future sickness. Amongst those who remained on ART, desire to prevent transmission and improve health were the most influential facilitators. Reasons for refusing and stopping ART were varied. ART-related side effects and feeling healthy were common barriers to ART initiation and adherence. Providing consistent pre-ART counseling, early support for patients experiencing side effects, and targeted efforts to bring women who stop treatment back into care may improve long term health outcomes.
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Affiliation(s)
- Maria H. Kim
- Baylor College of Medicine Department of Pediatrics, Section of Global Health and Retrovirology, Texas Children’s Hospital, Houston, Texas, United States of America
- Baylor College of Medicine—Abbott Fund Children's Clinical Centre of Excellence, Lilongwe, Malawi
| | - Amy Zhou
- Department of Sociology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Alick Mazenga
- Baylor College of Medicine—Abbott Fund Children's Clinical Centre of Excellence, Lilongwe, Malawi
| | - Saeed Ahmed
- Baylor College of Medicine Department of Pediatrics, Section of Global Health and Retrovirology, Texas Children’s Hospital, Houston, Texas, United States of America
- Baylor College of Medicine—Abbott Fund Children's Clinical Centre of Excellence, Lilongwe, Malawi
| | - Christine Markham
- Health Promotion and Behavioral Sciences, The University of Texas School of Public Health, Houston, Texas, United States of America
| | - Gerald Zomba
- HIV Unit, Malawi Ministry of Health, Lilongwe, Malawi
| | - Katie Simon
- Baylor College of Medicine—Abbott Fund Children's Clinical Centre of Excellence, Lilongwe, Malawi
| | - Peter N. Kazembe
- Baylor College of Medicine—Abbott Fund Children's Clinical Centre of Excellence, Lilongwe, Malawi
| | - Elaine J. Abrams
- ICAP, Mailman School of Public Health and College of Physicians & Surgeons, Columbia University, New York, New York, United States of America
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Swart M, Evans J, Skelton M, Castel S, Wiesner L, Smith PJ, Dandara C. An Expanded Analysis of Pharmacogenetics Determinants of Efavirenz Response that Includes 3'-UTR Single Nucleotide Polymorphisms among Black South African HIV/AIDS Patients. Front Genet 2016; 6:356. [PMID: 26779253 PMCID: PMC4703773 DOI: 10.3389/fgene.2015.00356] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/10/2015] [Indexed: 01/11/2023] Open
Abstract
Introduction: Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor prescribed as part of first-line highly active antiretroviral therapy (HAART) in South Africa. Despite administration of fixed doses of EFV, inter-individual variability in plasma concentrations has been reported. Poor treatment outcomes such as development of adverse drug reactions or treatment failure have been linked to EFV plasma concentrations outside the therapeutic range (1–4 μg/mL) in some studies. The drug metabolizing enzyme (DME), CYP2B6, is primarily responsible for EFV metabolism with minor contributions by CYP1A2, CYP2A6, CYP3A4, CYP3A5, and UGT2B7. DME coding genes are also regulated by microRNAs through targeting the 3′-untranslated region. Expanded analysis of 30 single nucleotide polymorphisms (SNPs), including those in the 3′-UTR, was performed to identify pharmacogenetics determinants of EFV plasma concentrations in addition to CYP2B6 c.516G>T and c.983T>C SNPs. Methods: SNPs in CYP1A2, CYP2B6, UGT2B7, and NR1I2 (PXR) were selected for genotyping among 222 Bantu-speaking South African HIV-infected patients receiving EFV-containing HAART. This study is a continuation of earlier pharmacogenetics studies emphasizing the role of genetic variation in the 3′-UTR of genes which products are either pharmacokinetic or pharmacodynamic targets of EFV. Results: Despite evaluating thirty SNPs, CYP2B6 c.516G>T and c.983T>C SNPs remain the most prominent predictors of EFV plasma concentration. Conclusion: We have shown that CYP2B6 c.516G>T and c.983T>C SNPs are the most important predictors of EFV plasma concentration after taking into account all other SNPs, including genetic variation in the 3′-UTR, and variables affecting EFV metabolism.
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Affiliation(s)
- Marelize Swart
- Division of Human Genetics, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Jonathan Evans
- Division of Human Genetics, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Michelle Skelton
- Division of Human Genetics, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Sandra Castel
- Division of Clinical Pharmacology, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Lubbe Wiesner
- Division of Clinical Pharmacology, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Peter J Smith
- Division of Clinical Pharmacology, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Collet Dandara
- Division of Human Genetics, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
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Sinxadi PZ, McIlleron HM, Dave JA, Smith PJ, Levitt NS, Haas DW, Maartens G. Plasma Efavirenz Concentrations Are Associated With Lipid and Glucose Concentrations. Medicine (Baltimore) 2016; 95:e2385. [PMID: 26765416 PMCID: PMC4718242 DOI: 10.1097/md.0000000000002385] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Efavirenz-based antiretroviral therapy (ART) has been associated with dyslipidemia and dysglycemia, risk factors for cardiovascular disease. However, the pathogenesis is not well understood. We characterized relationships between plasma efavirenz concentrations and lipid and glucose concentrations in HIV-infected South Africans.Participants on efavirenz-based ART were enrolled into a cross-sectional study. The oral glucose tolerance test was performed after an overnight fast, and plasma drawn for mid-dosing interval efavirenz, fasting total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, and triglycerides concentrations.Among 106 participants (77 women), median age was 38 years, median CD4 + T-cell count was 322 cells/μL, median duration on ART was 18 months, and median (interquartile range) efavirenz concentration was 2.23 (1.66 to 4.10) μg/mL. On multivariable analyses (adjusting for age, sex, body mass index, and ART duration) doubling of efavirenz concentrations resulted in mean changes in mmol/L (95%CI) of: total cholesterol (0.40 [0.22 to 0.59]), LDL cholesterol (0.19 [0.04 to 0.30]), HDL cholesterol (0.14 [0.07 to 0.20]), triglycerides (0.17 [0.03 to 0.33]), fasting glucose (0.18 [0.03 to 0.33]), and 2-h glucose concentrations (0.33 [0.08 to 0.60]). Among 57 participants with CYP2B6 genotype data, associations between slow metabolizer genotypes and metabolic profiles were generally consistent with those for measured efavirenz concentrations.Higher plasma efavirenz concentrations are associated with higher plasma lipid and glucose concentrations. This may have implications for long-term cardiovascular complications of efavirenz-based ART, particularly among populations with high prevalence of CYP2B6 slow metabolizer genotypes.
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Affiliation(s)
- Phumla Zuleika Sinxadi
- From the Division of Clinical Pharmacology, Department of Medicine, University of Cape Town (PZS, HMM, PJS, GM); Division of Endocrinology and Diabetic Medicine, Department of Medicine, University of Cape Town. Cape Town, South Africa (JAD, NSL); Vanderbilt University School of Medicine, Departments of Medicine, Pharmacology, Pathology, Microbiology & Immunology (DWH); Meharry Medical College, Department of Internal Medicine, Nashville, TN, United States of America (DWH)
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Cainelli F, Vento S. Liver disease in patients with HIV in sub-Saharan Africa. Lancet HIV 2015; 2:e412-3. [PMID: 26423647 DOI: 10.1016/s2352-3018(15)00179-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/26/2015] [Indexed: 01/11/2023]
Affiliation(s)
- Francesca Cainelli
- Department of Internal Medicine, Faculty of Medicine, University of Botswana, Gaborone, Botswana
| | - Sandro Vento
- Department of Internal Medicine, Faculty of Medicine, University of Botswana, Gaborone, Botswana.
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Asensi V, Collazos J, Valle-Garay E. Can antiretroviral therapy be tailored to each human immunodeficiency virus-infected individual? Role of pharmacogenomics. World J Virol 2015; 4:169-177. [PMID: 26279978 PMCID: PMC4534808 DOI: 10.5501/wjv.v4.i3.169] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 05/07/2015] [Accepted: 06/11/2015] [Indexed: 02/05/2023] Open
Abstract
Pharmacogenetics refers to the effect of single nucleotide polymorphisms (SNPs) within human genes on drug therapy outcome. Its study might help clinicians to increase the efficacy of antiretroviral drugs by improving their pharmacokinetics and pharmacodynamics and by decreasing their side effects. HLAB*5701 genotyping to avoid the abacavir-associated hypersensitivity reaction (HSR) is a cost-effective diagnostic tool, with a 100% of negative predictive value, and, therefore, it has been included in the guidelines for treatment of human immunodeficiency virus (HIV) infection. HALDRB*0101 associates with nevirapine-induced HSR. CYP2B6 SNPs modify efavirenz plasma levels and their genotyping help decreasing its central nervous system, hepatic and HSR toxicities. Cytokines SNPs might influence the development of drug-associated lipodystrophy. APOA5, APOB, APOC3 and APOE SNPs modify lipids plasma levels and might influence the coronary artery disease risk of HIV-infected individuals receiving antiretroviral therapy. UGT1A1*28 and ABCB1 (MDR1) 3435C > T SNPs modify atazanavir plasma levels and enhance hyperbilirubinemia. Much more effort needs to be still devoted to complete large prospective studies with multiple SNPs genotyping in order to reveal more clues about the role played by host genetics in antiretroviral drug efficacy and toxicity.
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