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Siemens A, Anderson SJ, Rassekh SR, Ross CJD, Carleton BC. A Systematic Review of Polygenic Models for Predicting Drug Outcomes. J Pers Med 2022; 12:jpm12091394. [PMID: 36143179 PMCID: PMC9505711 DOI: 10.3390/jpm12091394] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/21/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
Polygenic models have emerged as promising prediction tools for the prediction of complex traits. Currently, the majority of polygenic models are developed in the context of predicting disease risk, but polygenic models may also prove useful in predicting drug outcomes. This study sought to understand how polygenic models incorporating pharmacogenetic variants are being used in the prediction of drug outcomes. A systematic review was conducted with the aim of gaining insights into the methods used to construct polygenic models, as well as their performance in drug outcome prediction. The search uncovered 89 papers that incorporated pharmacogenetic variants in the development of polygenic models. It was found that the most common polygenic models were constructed for drug dosing predictions in anticoagulant therapies (n = 27). While nearly all studies found a significant association with their polygenic model and the investigated drug outcome (93.3%), less than half (47.2%) compared the performance of the polygenic model against clinical predictors, and even fewer (40.4%) sought to validate model predictions in an independent cohort. Additionally, the heterogeneity of reported performance measures makes the comparison of models across studies challenging. These findings highlight key considerations for future work in developing polygenic models in pharmacogenomic research.
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Affiliation(s)
- Angela Siemens
- Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1, Canada
- BC Children’s Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - Spencer J. Anderson
- Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1, Canada
- BC Children’s Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
| | - S. Rod Rassekh
- Division of Translational Therapeutics, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3V4, Canada
- Division of Oncology, Hematology and Bone Marrow Transplant, University of British Columbia, Vancouver, BC V6H 3V4, Canada
| | - Colin J. D. Ross
- Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1, Canada
- BC Children’s Hospital Research Institute, Vancouver, BC V5Z 4H4, Canada
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Bruce C. Carleton
- Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3N1, Canada
- Division of Translational Therapeutics, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6H 3V4, Canada
- Pharmaceutical Outcomes Programme, British Columbia Children’s Hospital, Vancouver, BC V5Z 4H4, Canada
- Correspondence:
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Varnai R, Sipeky C, Nagy L, Balogh S, Melegh B. CYP2C9 and VKORC1 in therapeutic dosing and safety of acenocoumarol treatment: implication for clinical practice in Hungary. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 56:282-289. [PMID: 29055218 DOI: 10.1016/j.etap.2017.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/29/2017] [Accepted: 10/07/2017] [Indexed: 06/07/2023]
Abstract
The purpose of this work was to investigate the contribution of CYP2C9 and VKORC1 to acenocoumarol (AC) dose variability, bleeding events in Hungary. The study recruited 117 patients on long-term AC therapy (INR 2-3), and 510 healthy individuals to model the findings. Patients were genotyped for alleles proved to affect lower AC overdose CYP2C9*2, CYP2C9*3, VKORC1*2. Additionally, we tested VKORC1*3, VKORC1*4 to examine their effect in patients with higher AC requirements. Most impact on dose reduction is accountable for CYP2C9*2/*3 (59%) and for VKORC1*2/*2 (45.5%), and on dose increase for newly evaluated VKORC1*3/*4 (22.5%) diplotypes. VKORC1*3 and *4 alleles seem to balance the dose-reducing effect of VKORC1*2 allele. Being a carrier of combination of VKORC1*2 and CYP2C9*2,*3 polymorphisms, rather than of one of these SNPs, is associated with higher risk of over-anticoagulation (up to 34.3%) in long-term AC treatment. The pharmacogenetic dosing algorithm involving VKORC1, CYP2C9 diplotypes and age explains 30.4% of AC dosing variability (p<6.10×10-9). Correlation between the studied diplotypes and bleeding events could not be revealed.
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Affiliation(s)
- Reka Varnai
- University of Pecs, Department of Primary Health Care, H-7623 Pecs, Rakoczi 2, Hungary; University of Pécs, Faculty of Health Sciences, Doctoral School of Health Sciences, H-7621 Pécs, Vörösmarty 4, Hungary
| | - Csilla Sipeky
- University of Pecs, Clinical Centre, Department of Medical Genetics, H-7624 Pecs, Szigeti 12, Hungary.
| | - Lajos Nagy
- University of Pecs, Department of Primary Health Care, H-7623 Pecs, Rakoczi 2, Hungary
| | - Sandor Balogh
- University of Pecs, Department of Primary Health Care, H-7623 Pecs, Rakoczi 2, Hungary
| | - Bela Melegh
- University of Pecs, Clinical Centre, Department of Medical Genetics, H-7624 Pecs, Szigeti 12, Hungary
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Genetic determinants of variability in warfarin response after the dose-titration phase. Pharmacogenet Genomics 2017; 26:510-516. [PMID: 27632229 DOI: 10.1097/fpc.0000000000000244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVES Genetic factors contribute considerably toward variability in warfarin dose requirements and are important in the dose-titration phase; their effects on the stability of anticoagulation later in therapy are not known. METHODS Using deidentified electronic medical records linked to a DNA-biobank, we studied 140 African-Americans and 943 European-Americans after the warfarin dose-titration phase. We genotyped 12 single nucleotide polymorphisms in genes (CYP2C9, VKORC1, CYP4F2, GGCX, EPHX1, CALU) associated with altered warfarin dose requirements and tested their associations with international normalized ratio variability (INRVAR) and percent time in therapeutic range in European-Americans and African-Americans. RESULTS One allele copy of rs2108622 in CYP4F2 was associated with a 15% [95% confidence interval (CI): 1-26, P=0.03] decrease in the median INRVAR in European-Americans. In African-Americans, GGCX variants rs11676382 and rs699664 were associated with 4.16-fold (95% CI: 1.45-11.97, P=0.009) and 1.50-fold (95% CI: 1.07-2.08, P=0.02) changes in the median INRVAR per variant allele copy, respectively; rs11676382 was also significantly associated with a 23.19% (95% CI: 5.89-40.48, P=0.01) decrease in time in therapeutic range. The total variation in INRVAR explained by both clinical factors and rs2108622 was 5.2% for European-Americans. In African-Americans, the inclusion of GGCX variants rs11676382 and rs699664, and the CYP2C9*8 variant rs7900194 explained ∼29% of the variation in INRVAR. CONCLUSION The stability of anticoagulation after the warfarin dose-titration phase is differentially affected by variants in CYP4F2 in European-Americans and GGCX loci in African-Americans.
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Jiménez-Varo E, Cañadas-Garre M, Garcés-Robles V, Gutiérrez-Pimentel MJ, Calleja-Hernández MÁ. Extrapolation of acenocoumarol pharmacogenetic algorithms. Vascul Pharmacol 2015; 74:151-157. [PMID: 26122664 DOI: 10.1016/j.vph.2015.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 06/01/2015] [Accepted: 06/23/2015] [Indexed: 01/29/2023]
Abstract
INTRODUCTION Acenocoumarol (ACN) has a narrow therapeutic range that is especially difficult to control at the start of its administration. Various dosing pharmacogenetic-guided dosing algorithms have been developed, but further work on their external validation is required. The aim of this study was to evaluate the extrapolation of pharmacogenetic algorithms for ACN as an alternative to the development of a specific algorithm for a given population. MATERIAL AND METHODS The predictive performance, deviation, accuracy, and clinical significance of five pharmacogenetic algorithms (EU-PACT, Borobia, Rathore, Markatos, Krishna Kumar) were compared in 189 stable ACN patients representing all indications for anticoagulant treatment. RESULTS The correlation between the dose predictions of the five pharmacogenetic models ranged from 7.7 to 70.6% and the percentage of patients with a correct prediction (deviation ≤20% from actual ACN dose) ranged from 5.9 to 40.7%. EU-PACT and Borobia pharmacogenetic dosing algorithms were the most accurate in our setting and evidenced the best clinical performance. CONCLUSIONS Among the five models studied, the EU-PACT and Borobia pharmacogenetic dosing algorithms demonstrated the best potential for extrapolation.
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Affiliation(s)
- Enrique Jiménez-Varo
- Pharmacogenetics Unit, UGC Provincial de Farmacia de Granada, Instituto de Investigación Biosanitaria de Granada, Complejo Hospitalario Universitario de Granada, Avda. Fuerzas Armadas, 2, 18014 Granada, Spain.
| | - Marisa Cañadas-Garre
- Pharmacogenetics Unit, UGC Provincial de Farmacia de Granada, Instituto de Investigación Biosanitaria de Granada, Complejo Hospitalario Universitario de Granada, Avda. Fuerzas Armadas, 2, 18014 Granada, Spain.
| | - Víctor Garcés-Robles
- Pharmacogenetics Unit, UGC Provincial de Farmacia de Granada, Instituto de Investigación Biosanitaria de Granada, Complejo Hospitalario Universitario de Granada, Avda. Fuerzas Armadas, 2, 18014 Granada, Spain.
| | - María José Gutiérrez-Pimentel
- Haematology Department, Complejo Hospitalario Universitario de Granada, Avda. Fuerzas Armadas, 2, 18014 Granada, Spain.
| | - Miguel Ángel Calleja-Hernández
- Pharmacogenetics Unit, UGC Provincial de Farmacia de Granada, Instituto de Investigación Biosanitaria de Granada, Complejo Hospitalario Universitario de Granada, Avda. Fuerzas Armadas, 2, 18014 Granada, Spain.
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Jiménez-Varo E, Cañadas-Garre M, Henriques CI, Pinheiro AM, Gutiérrez-Pimentel MJ, Calleja-Hernández MÁ. Pharmacogenetics role in the safety of acenocoumarol therapy. Thromb Haemost 2014; 112:522-36. [PMID: 24919870 DOI: 10.1160/th13-11-0941] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 04/23/2014] [Indexed: 11/05/2022]
Abstract
Vitamin K antagonists (VKAs) remain as the most prescribed drug for treatment and prevention of thrombotic disorders in many countries, despite the recent approval of the new oral anticoagulants (NOACs). Although effectiveness and safety of VKAs are tightly associated to maintaining the patient within the international normalised ratio (INR) therapeutic range (TWR), they have been likened to NOACs when patients are in good INR control (≥66% of TWR). Therefore, assessing the safety of patients should be a priority in the selection of the anticoagulation therapy. The aim of this study was to evaluate the association between CYP2C9*2, CYP2C9*3, VKORC1, CYP4F2*3, ABCB1 C3435T, APOE, CYP2C19*2 and CYP2C19*17 gene polymorphisms and treatment safety in 128 patients diagnosed with atrial fibrillation or venous thromboembolism during the initial first seven months of acenocoumarol therapy. After the first month, VKORC1-T-allele and APOE-E3/E3 genotype were independently associated to higher time above therapeutic range (TAR) and lower time below the therapeutic range (TBR). After seven months, VKORC1 T-allele predicted higher TAR, and was also associated to increased INR>4, particularly the TT-genotype (odds ratio [OR]: 32; 95% confidence interval [CI95%]: 6-175; p=810⁻⁵). C-alleles for CYP2C9*3 (OR: 5.5; CI95%: 1.8-17; p=0.003) and ABCB1 (OR: 8.9;CI95%: 1.1-70; p=0.039) independently influenced on INR>6 . Patients VKORC1-TT/ABCB1-C remained 26.8% [19.7-38.9] TAR, with associated relative risk (RR) for INR>4 1.8 higher (CI95%: 1.2-2.5; p=0.015). Patients VKORC1-TT also presented the highest risk of bleeding events (RR: 3.5;CI95%: 1.4-8.4; p=0,010). In conclusion, VKORC1, CYP2C9*3, APOE and ABCB1 genotypes should be considered in prevention of overanticoagulation and bleeding events in the initiation of acenocoumarol therapy.
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Affiliation(s)
| | - M Cañadas-Garre
- Marisa Cañadas-Garre, PhD, Pharmacogenetics Unit, UGC Provincial de Farmacia de Granada, Instituto de Investigación Biosanitaria de Granada, Complejo Hospitalario de Granada, Avda. Fuerzas Armadas, 2, 18014 Granada, Spain, Tel.: +34 958020108, Fax: +34 958020004, E-mail:
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Cerezo-Manchado JJ, Roldan V, Rosafalco M, Anton AI, Arroyo AB, Garcia-Barbera N, Martínez AB, Padilla J, Corral J, Vicente V, Gonzalez-Conejero R. Effect of VKORC1, CYP2C9 and CYP4F2 genetic variants in early outcomes during acenocoumarol treatment. Pharmacogenomics 2014; 15:987-96. [DOI: 10.2217/pgs.13.232] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aim: To analyze VKORC1, CYP2C9 and CYP4F2 polymorphisms in relation to the main outcomes in the first stages of acenocoumarol therapy. Patients & methods: Nine hundred and forty one patients who had started therapy and in whom time to stable dosage, time to over-anticoagulation and adverse events occurred during 3 first months were retrospectively analyzed. Results: VKORC1 AA patients needed fewer days to reach stable dosage (p = 0.017). International normalized ratio [INR] at 72 h, and VKORC1 and CYP2C9 genotypes conditioned INR values >2.5 (p < 0.001, p = 0.002 and p < 0.001, respectively), whereas CYP4F2 T carriers had a low risk of the same outcome (p = 0.009). In regards to combined genotypes, CYP4F2 had a significant effect on over-anticoagulation at the beginning of therapy except for the VKORC1 AA and CYP2C9*3 combination. Conclusion: In addition to VKORC1 and CYP2C9, CYP4F2 gene has a slight but significant role in reaching INR >2.5 during the first weeks of acenocoumarol therapy. Original submitted 22 July 2013; Revision submitted 14 November 2013
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Affiliation(s)
- Juan Jose Cerezo-Manchado
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | - Vanessa Roldan
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | | | - Ana Isabel Anton
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | - Ana Belen Arroyo
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | - Nuria Garcia-Barbera
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | - Ana Belen Martínez
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | - Jose Padilla
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | - Javier Corral
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | - Vicente Vicente
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
| | - Rocio Gonzalez-Conejero
- Hospital Universitario Morales Meseguer & Centro Regional de Hemodonacion, University of Murcia, Ronda de Garay s/n, 30003, IMIB, Murcia, Spain
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De T, Christopher R, Nagaraja D. Influence of CYP2C9 polymorphism and phenytoin co-administration on acenocoumarol dose in patients with cerebral venous thrombosis. Thromb Res 2014; 133:729-35. [DOI: 10.1016/j.thromres.2014.01.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/20/2014] [Accepted: 01/28/2014] [Indexed: 12/19/2022]
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CYP2C9, VKORC1, CYP4F2, ABCB1 and F5 variants: influence on quality of long-term anticoagulation. Pharmacol Rep 2014; 66:243-9. [PMID: 24911077 DOI: 10.1016/j.pharep.2013.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/19/2013] [Accepted: 09/06/2013] [Indexed: 11/22/2022]
Abstract
AIMS The study aims to evaluate the impact of genetic, demographic and clinical data on various measures of outcome of anticoagulation quality in patients. PATIENTS AND METHODS The study consisted of 310 patients receiving long-term oral anticoagulation therapy in our hospital. Apart from demographic and clinical variables, 21 SNPs (in 7 genes) were analyzed and compared with the outcomes of anticoagulation therapy. Various outcomes that were measured are; supra therapeutic INRs (INR >3, >6), anticoagulation stabilization, time taken to stabilize and proportion of INRs within (2-3), above (>3) and below (<2) therapeutic range. RESULTS Supra therapeutic INRs were influenced by CYP2C9*2, *3, CYP4F2 rs2108622, VKORC1-1639G>A, 1173C>T, rs55894764 along with concomitant drugs, smoking, body weight and height. Persistently fluctuating INRs/absolute instability correlated with VKORC1-1639G>A, gender, height and body mass index. The time taken to stabilize was associated with CYP4F2 rs2108622, CYP2C9*14, smoking, clinical indication and concomitant drugs. The overall distribution of INR was influenced by variants in CYP4F2 rs2108622, CYP2C9*3, rs9332230, VKORC1 1173C>T, -1639G>A, rs55894764, ABCB1 rs2032582, rs1128503, rs1045642 and F5 rs6025, age, smoking and concomitant drugs. CONCLUSIONS Knowledge of factors influencing the quality of long term anticoagulation can help clinicians to customize therapy either by dose variation, therapy with alternate choice of drug, concurrent heparin therapy and/or frequent INR monitoring.
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Grossi E, Podda GM, Pugliano M, Gabba S, Verri A, Carpani G, Buscema M, Casazza G, Cattaneo M. Prediction of optimal warfarin maintenance dose using advanced artificial neural networks. Pharmacogenomics 2014; 15:29-37. [PMID: 24329188 DOI: 10.2217/pgs.13.212] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND In recent years, pharmacogenetic algorithms were developed for estimating the appropriate dose of vitamin K antagonists. AIM To evaluate the performance of new generation artificial neural networks (ANNs) to predict the warfarin maintenance dose. METHODS Demographic, clinical and genetic data (CYP2C9 and VKORC1 polymorphisms) from 377 patients treated with warfarin were used. The final prediction model was based on 23 variables selected by TWIST® system within a bipartite division of the data set (training and testing) protocol. RESULTS The ANN algorithm reached high accuracy, with an average absolute error of 5.7 mg of the warfarin maintenance dose. In the subset of patients requiring ≤21 mg and 21-49 mg (45 and 51% of the cohort, respectively) the absolute error was 3.86 mg and 5.45 with a high percentage of subjects being correctly identified (71 and 73%, respectively). CONCLUSION ANN appears to be a promising tool for vitamin K antagonist maintenance dose prediction.
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Genotype-phenotype correlations in patients treated with acenocoumarol / Corelaţii genotip-fenotip la pacienţii trataţi cu acenocumarol. REV ROMANA MED LAB 2014. [DOI: 10.2478/rrlm-2014-0032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Hernandez W, Gamazon ER, Aquino-Michaels K, Patel S, O'Brien TJ, Harralson AF, Kittles RA, Barbour A, Tuck M, McIntosh SD, Douglas JN, Nicolae D, Cavallari LH, Perera MA. Ethnicity-specific pharmacogenetics: the case of warfarin in African Americans. THE PHARMACOGENOMICS JOURNAL 2013; 14:223-8. [PMID: 24018621 DOI: 10.1038/tpj.2013.34] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 07/18/2013] [Accepted: 07/22/2013] [Indexed: 01/05/2023]
Abstract
Using a derivation cohort (N=349), we developed the first warfarin dosing algorithm that includes recently discovered polymorphisms in VKORC1 and CYP2C9 associated with warfarin dose requirement in African Americans (AAs). We tested our novel algorithm in an independent cohort of 129 AAs and compared the dose prediction to the International Warfarin Pharmacogenetics Consortium (IWPC) dosing algorithms. Our algorithm explains more of the phenotypic variation (R(2)=0.27) than the IWPC pharmacogenomics (R(2)=0.15) or clinical (R(2)=0.16) algorithms. Among high-dose patients, our algorithm predicted a higher proportion of patients within 20% of stable warfarin dose (45% vs 29% and 2% in the IWPC pharmacogenomics and clinical algorithms, respectively). In contrast to our novel algorithm, a significant inverse correlation between predicted dose and percent West African ancestry was observed for the IWPC pharmacogenomics algorithm among patients requiring ⩾60 mg per week (β=-2.04, P=0.02).
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Affiliation(s)
- W Hernandez
- Department of Medicine, Section of Genetic Medicine, University of Chicago, Chicago, IL, USA
| | - E R Gamazon
- Department of Medicine, Section of Genetic Medicine, University of Chicago, Chicago, IL, USA
| | - K Aquino-Michaels
- Department of Medicine, Section of Genetic Medicine, University of Chicago, Chicago, IL, USA
| | - S Patel
- Department of Pharmacy, University of Illinois, Chicago, IL, USA
| | - T J O'Brien
- Department of Pharmacology and Physiology, The George Washington University, Washington DC, USA
| | - A F Harralson
- 1] Department of Pharmacology and Physiology, The George Washington University, Washington DC, USA [2] Department of Pharmacogenomics, Bernard J. Dunn School of Pharmacy, Shenandoah University, Ashburn, VA, USA
| | - R A Kittles
- Department of Medicine, Institute of Human Genetics, University of Illinois, Chicago, IL, USA
| | - A Barbour
- Department of Medicine, The George Washington University, Washington DC, USA
| | - M Tuck
- Department of Veterans Affairs, Uniformed Services University of the Health Sciences, Washington DC, USA
| | - S D McIntosh
- 1] Department of Medicine, The George Washington University, Washington DC, USA [2] Department of Veterans Affairs, Uniformed Services University of the Health Sciences, Washington DC, USA
| | - J N Douglas
- Department of Veterans Affairs, Uniformed Services University of the Health Sciences, Washington DC, USA
| | - D Nicolae
- Department of Medicine, Section of Genetic Medicine, University of Chicago, Chicago, IL, USA
| | - L H Cavallari
- Department of Pharmacy, University of Illinois, Chicago, IL, USA
| | - M A Perera
- Department of Medicine, Section of Genetic Medicine, University of Chicago, Chicago, IL, USA
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Samer CF, Lorenzini KI, Rollason V, Daali Y, Desmeules JA. Applications of CYP450 testing in the clinical setting. Mol Diagn Ther 2013; 17:165-84. [PMID: 23588782 PMCID: PMC3663206 DOI: 10.1007/s40291-013-0028-5] [Citation(s) in RCA: 218] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Interindividual variability in drug response is a major clinical problem. Polymedication and genetic polymorphisms modulating drug-metabolising enzyme activities (cytochromes P450, CYP) are identified sources of variability in drug responses. We present here the relevant data on the clinical impact of the major CYP polymorphisms (CYP2D6, CYP2C19 and CYP2C9) on drug therapy where genotyping and phenotyping may be considered, and the guidelines developed when available. CYP2D6 is responsible for the oxidative metabolism of up to 25% of commonly prescribed drugs such as antidepressants, antipsychotics, opioids, antiarrythmics and tamoxifen. The ultrarapid metaboliser (UM) phenotype is recognised as a cause of therapeutic inefficacy of antidepressant, whereas an increased risk of toxicity has been reported in poor metabolisers (PMs) with several psychotropics (desipramine, venlafaxine, amitriptyline, haloperidol). CYP2D6 polymorphism influences the analgesic response to prodrug opioids (codeine, tramadol and oxycodone). In PMs for CYP2D6, reduced analgesic effects have been observed, whereas in UMs cases of life-threatening toxicity have been reported with tramadol and codeine. CYP2D6 PM phenotype has been associated with an increased risk of toxicity of metoprolol, timolol, carvedilol and propafenone. Although conflicting results have been reported regarding the association between CYP2D6 genotype and tamoxifen effects, CYP2D6 genotyping may be useful in selecting adjuvant hormonal therapy in postmenopausal women. CYP2C19 is responsible for metabolising clopidogrel, proton pump inhibitors (PPIs) and some antidepressants. Carriers of CYP2C19 variant alleles exhibit a reduced capacity to produce the active metabolite of clopidogrel, and are at increased risk of adverse cardiovascular events. For PPIs, it has been shown that the mean intragastric pH values and the Helicobacter pylori eradication rates were higher in carriers of CYP2C19 variant alleles. CYP2C19 is involved in the metabolism of several antidepressants. As a result of an increased risk of adverse effects in CYP2C19 PMs, dose reductions are recommended for some agents (imipramine, sertraline). CYP2C9 is responsible for metabolising vitamin K antagonists (VKAs), non-steroidal anti-inflammatory drugs (NSAIDs), sulfonylureas, angiotensin II receptor antagonists and phenytoin. For VKAs, CYP2C9 polymorphism has been associated with lower doses, longer time to reach treatment stability and higher frequencies of supratherapeutic international normalised ratios (INRs). Prescribing algorithms are available in order to adapt dosing to genotype. Although the existing data are controversial, some studies have suggested an increased risk of NSAID-associated gastrointestinal bleeding in carriers of CYP2C9 variant alleles. A relationship between CYP2C9 polymorphisms and the pharmacokinetics of sulfonylureas and angiotensin II receptor antagonists has also been observed. The clinical impact in terms of hypoglycaemia and blood pressure was, however, modest. Finally, homozygous and heterozygous carriers of CYP2C9 variant alleles require lower doses of phenytoin to reach therapeutic plasma concentrations, and are at increased risk of toxicity. New diagnostic techniques made safer and easier should allow quicker diagnosis of metabolic variations. Genotyping and phenotyping may therefore be considered where dosing guidelines according to CYP genotype have been published, and help identify the right molecule for the right patient.
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Affiliation(s)
- C F Samer
- Clinical Pharmacology and Toxicology, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva, Switzerland.
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Kumar DK, Shewade DG, Surendiran A, Adithan C. Genetic variation and haplotype structure of the gene Vitamin K epoxide reductase complex, subunit 1 in the Tamilian population. J Pharmacol Pharmacother 2013; 4:53-8. [PMID: 23662025 PMCID: PMC3643344 DOI: 10.4103/0976-500x.107683] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE To study the genetic variation and haplotype structure of Vitamin K epoxide reductase complex, subunit 1 (VKORC1) gene in the Tamilian population. MATERIALS AND METHODS The study was performed on 210 unrelated, healthy volunteers of the Tamilian population, of either sex between the age group of 18-60 years. Five ml of venous blood sample was collected using sodium ethylene diamine tetra acetic acid (EDTA) as anticoagulant. DNA was extracted using phenol-chloroform extraction method. Eight single nucleotide polymorphisms (SNPs) VKORC1 rs9923231 (G), rs7196161 (T), rs2884737 (T), rs17708472 (C), rs9934438 (C), rs8050894 (G), rs23596121 (C), and rs7294 (A) were studied using real-time quantitative Polymerase Chain Reaction (qPCR) method and they were included for constructing five-major haplotype blocks of VKORC1 gene. RESULTS The major alleles of VKORC1 rs9923231 (G), rs7196161 (T), rs2884737 (T), rs17708472 (C), rs9934438 (C), rs8050894 (G), and rs23596121 (C), were found to be at frequencies of 90.0%, 89.2%, 90.9%, 94.1%, 90.7%, 89.5% and 91.2%, respectively. The variant allele of VKORC1 rs7294 (A) was more frequent (83.6%) in the Tamilian population. The frequencies of haplotypes HAP1 (GTTCCGCA), HAP2 (ACGCTCTG), HAP3 (GTTTCGCG), HAP4 (GTTCCGCG) and HAP5 (GCTCCCCG) were found to be 80.0%, 7.4%, 4.7%, 1.5% and 1.1%, respectively. CONCLUSION In the present study the allele- frequency distributions, genotype and haplotype frequencies of the VKORC1 gene was considered. The findings of this study provide the genetic information required for learning the association of VKORC1 genetic variation and oral anticoagulant dose variability among patients receiving oral anticoagulants in the Tamilian population.
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Affiliation(s)
- Dhakchinamoorthi Krishna Kumar
- Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, India
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Esmerian MO, Mitri Z, Habbal MZ, Geryess E, Zaatari G, Alam S, Skouri HN, Mahfouz RA, Taher A, Zgheib NK. Influence ofCYP2C9andVKORC1Polymorphisms on Warfarin and Acenocoumarol in a Sample of Lebanese People. J Clin Pharmacol 2013; 51:1418-28. [DOI: 10.1177/0091270010382910] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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A multiplex assay to detect variations in the CYP2C9, VKORC1, CYP4F2 and APOE genes involved in acenocoumarol metabolism. Clin Biochem 2013; 46:167-9. [DOI: 10.1016/j.clinbiochem.2012.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 07/24/2012] [Accepted: 08/01/2012] [Indexed: 01/26/2023]
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Carcas AJ, Borobia AM, Velasco M, Abad-Santos F, Díaz MQ, Fernández-Capitán C, Ruiz-Giménez N, Madridano O, Sillero PL. Efficiency and effectiveness of the use of an acenocoumarol pharmacogenetic dosing algorithm versus usual care in patients with venous thromboembolic disease initiating oral anticoagulation: study protocol for a randomized controlled trial. Trials 2012; 13:239. [PMID: 23237631 PMCID: PMC3543328 DOI: 10.1186/1745-6215-13-239] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 11/08/2012] [Indexed: 12/13/2022] Open
Abstract
Background Hemorrhagic events are frequent in patients on treatment with antivitamin-K oral anticoagulants due to their narrow therapeutic margin. Studies performed with acenocoumarol have shown the relationship between demographic, clinical and genotypic variants and the response to these drugs. Once the influence of these genetic and clinical factors on the dose of acenocoumarol needed to maintain a stable international normalized ratio (INR) has been demonstrated, new strategies need to be developed to predict the appropriate doses of this drug. Several pharmacogenetic algorithms have been developed for warfarin, but only three have been developed for acenocoumarol. After the development of a pharmacogenetic algorithm, the obvious next step is to demonstrate its effectiveness and utility by means of a randomized controlled trial. The aim of this study is to evaluate the effectiveness and efficiency of an acenocoumarol dosing algorithm developed by our group which includes demographic, clinical and pharmacogenetic variables (VKORC1, CYP2C9, CYP4F2 and ApoE) in patients with venous thromboembolism (VTE). Methods and design This is a multicenter, single blind, randomized controlled clinical trial. The protocol has been approved by La Paz University Hospital Research Ethics Committee and by the Spanish Drug Agency. Two hundred and forty patients with VTE in which oral anticoagulant therapy is indicated will be included. Randomization (case/control 1:1) will be stratified by center. Acenocoumarol dose in the control group will be scheduled and adjusted following common clinical practice; in the experimental arm dosing will be following an individualized algorithm developed and validated by our group. Patients will be followed for three months. The main endpoints are: 1) Percentage of patients with INR within the therapeutic range on day seven after initiation of oral anticoagulant therapy; 2) Time from the start of oral anticoagulant treatment to achievement of a stable INR within the therapeutic range; 3) Number of INR determinations within the therapeutic range in the first six weeks of treatment. Discussion To date, there are no clinical trials comparing pharmacogenetic acenocoumarol dosing algorithm versus routine clinical practice in VTE. Implementation of this pharmacogenetic algorithm in the clinical practice routine could reduce side effects and improve patient safety. Trial registration Eudra CT. Identifier: 2009-016643-18.
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Affiliation(s)
- Antonio J Carcas
- Clinical Pharmacology Department, La Paz University Hospital, Pharmacology Department, School of Medicine, Universidad Autónoma de Madrid, IdiPAZ, Paseo de la Castellana, 261, 28046, Madrid, Spain.
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Abstract
The objective of our present study was to develop a warfarin dosing algorithm for the Omani patients, as performances of warfarin dosing algorithms vary across populations with impact on the daily maintenance dose. We studied the functional polymorphisms of CYP2C9, CYP4F2 and VKORC1 genes to evaluate their impact on the warfarin maintenance dose in an admixed Omani patient cohort with Caucasian, African and Asian ancestries. We observed a 64-fold inter-patient variability for warfarin to achieve stable international normalized ratio in these patients. Univariate analysis revealed that age, gender, weight, atrial fibrillation, deep vein thrombosis/pulmonary embolism and variant genotypes of CYP2C9 and VKORC1 loci were significantly associated with warfarin dose in the studied patient population. However, multiple regression model showed that only the atrial fibrillation, and homozygous CYP2C9 variant genotypes (*2/*3 and *3/*3) and VKORC1 GA and AA genotypes remained significant. A multivariate model, which included demographic, clinical and pharmacogenetic variables together explained 63% of the overall inter-patient variability in warfarin dose requirement in this microgeographically defined, ethnically admixed Omani patient cohort on warfarin. This locally developed model performed much better than the International Warfarin Pharmacogenetics Consortium (IWPC) model as the latter could only explain 34% of the inter-patient variability in Omani patients. VKORC1 3673G>A polymorphism emerged as the single most important predictor of warfarin dose variability, even in this admixed population (partial R(2)=0.45).
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Borobia AM, Lubomirov R, Ramírez E, Lorenzo A, Campos A, Muñoz-Romo R, Fernández-Capitán C, Frías J, Carcas AJ. An acenocoumarol dosing algorithm using clinical and pharmacogenetic data in Spanish patients with thromboembolic disease. PLoS One 2012; 7:e41360. [PMID: 22911785 PMCID: PMC3401172 DOI: 10.1371/journal.pone.0041360] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 06/20/2012] [Indexed: 12/13/2022] Open
Abstract
Appropriate dosing of coumarins is difficult to establish, due to significant inter-individual variability in the dose required to obtain stable anticoagulation. Several genetic and other clinical factors have been associated with the coumarins dose, and some pharmacogenetic-guided dosing algorithms for warfarin and acenocoumarol have been developed for mixed populations. We recruited 147 patients with thromboembolic disease who were on stable doses and with an international normalized ratio (INR) between 2 and 3. We ascertained the influence of clinical and genetic variables on the stable acenocoumarol dose by multiple linear regression analysis in a derivation cohort (DC; n = 117) and developed an algorithm for dosing that included clinical factors (age, body mass index and concomitant drugs) and genetic variations of VKORC1, CYP2C9, CYP4F2 and APOE. For purposes of comparison, a model including only clinical data was created. The clinical factors explained 22% of the dose variability, which increased to 60.6% when pharmacogenetic information was included (p<0.001); CYP4F2 and APOE variants explained 4.9% of this variability. The mean absolute error of the predicted acenocoumarol dose (mg/week) obtained with the pharmacogenetic algorithm was 3.63 vs. 5.08 mg/week with the clinical algorithm (95% CI: 0.88 to 2.04). In the testing cohort (n = 30), clinical factors explained a mere 7% of the dose variability, compared to 39% explained by the pharmacogenetic algorithm. Considering a more clinically relevant parameter, the pharmacogenetic algorithm correctly predicted the real stable dose in 59.8% of the cases (DC) vs. only 37.6% predicted by the clinical algorithm (95% CI: 10 to 35). Therefore the number of patients needed to genotype to avoid one over- or under-dosing was estimated to be 5.
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Affiliation(s)
- Alberto M. Borobia
- Clinical Pharmacology Service, La Paz University Hospital, Pharmacology Department, School of Medicine, Universidad Autónoma de Madrid, IdiPAZ, Madrid, Spain
- * E-mail: (AJC); (AMB)
| | - Rubin Lubomirov
- Pharmacology Department, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Elena Ramírez
- Clinical Pharmacology Service, La Paz University Hospital, Pharmacology Department, School of Medicine, Universidad Autónoma de Madrid, IdiPAZ, Madrid, Spain
| | - Alicia Lorenzo
- Internal Medicine Department, La Paz University Hospital, Madrid, Spain
| | - Armando Campos
- Clinical Pharmacology Service, La Paz University Hospital, Pharmacology Department, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Raul Muñoz-Romo
- Clinical Pharmacology Service, La Paz University Hospital, Pharmacology Department, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Carmen Fernández-Capitán
- Internal Medicine Department, La Paz University Hospital, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jesús Frías
- Clinical Pharmacology Service, La Paz University Hospital, Pharmacology Department, School of Medicine, Universidad Autónoma de Madrid, IdiPAZ, Madrid, Spain
| | - Antonio J. Carcas
- Clinical Pharmacology Service, La Paz University Hospital, Pharmacology Department, School of Medicine, Universidad Autónoma de Madrid, IdiPAZ, Madrid, Spain
- * E-mail: (AJC); (AMB)
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Acenocoumarol sensitivity and pharmacokinetic characterization of CYP2C9 *5/*8,*8/*11,*9/*11 and VKORC1*2 in black African healthy Beninese subjects. Eur J Drug Metab Pharmacokinet 2011; 37:125-32. [PMID: 21811894 DOI: 10.1007/s13318-011-0056-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/14/2011] [Indexed: 10/17/2022]
Abstract
This study aimed at investigating the contribution of CYP2C9 and VKORC1 genetic polymorphisms to inter-individual variability of acenocoumarol pharmacokinetics and pharmacodynamics in Black Africans from Benin. Fifty-one healthy volunteers were genotyped for VKORC1 1173C>T polymorphism. All of the subjects had previously been genotyped for CYP2C9*5, CYP2C9*6, CYP2C9*8, CYP2C9*9 and CYP2C9*11 alleles. Thirty-six subjects were phenotyped with a single 8 mg oral dose of acenocoumarol by measuring plasma concentrations of (R)- and (S)-acenocoumarol 8 and 24 h after the administration using chiral liquid-chromatography tandem mass-spectrometry. International normalized ratio (INR) values were determined prior to and 24 h after the drug intake. The allele frequency of VKORC1 variant (1173C>T) was 1.96% (95% CI 0.0-4.65%). The INR values did not show statistically significant difference between the CYP2C9 genotypes, but were correlated with body mass index and age at 24 h post-dosing (P < 0.05). At 8 h post dose, the (S)-acenocoumarol concentrations in the CYP2C9*5/*8 and CYP2C9*9/*11 genotypes were about 1.9 and 5.1 fold higher compared with the CYP2C9*1/*1 genotype and 2.2- and 6.0-fold higher compared with the CYP2C9*1/*9 group, respectively. The results indicated that pharmacodynamic response to acenocoumarol is highly variable between the subjects. This variability seems to be associated with CYP2C9*5/*8 and *9/*11 variant and demographic factors (age and weight) in Beninese subjects. Significant association between plasma (S)-acenocoumarol concentration and CYP2C9 genotypes suggested the use of (S)-acenocoumarol for the phenotyping purpose. Larger number of subjects is needed to study the effect of VKORC1 1173C>T variant due to its low frequency in Beninese population.
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Genetic variation of VKORC1 and CYP4F2 genes related to warfarin maintenance dose in patients with myocardial infarction. J Biomed Biotechnol 2010; 2011:739751. [PMID: 21127708 PMCID: PMC2992873 DOI: 10.1155/2011/739751] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 10/06/2010] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to investigate whether the VKORC1*3 (rs7294/9041 G > A), VKORC1*4 (rs17708472/6009 C > T), and CYP4F2 (rs2108622/1347 C > T) polymorphisms were associated with elevated warfarin maintenance dose requirements in patients with myocardial infarction (n = 105) from the Warfarin Aspirin Reinfarction Study (WARIS-II). We found significant associations between elevated warfarin dose requirements and VKORC1*3 and VKORC1*4 polymorphisms (P = .001 and P = .004, resp.), whereas CYP4F2 (1347 C > T) showed a weak association on higher warfarin dose requirements (P = .09). However, analysing these variant alleles in a regression analysis together with our previously reported data on VKORC1*2, CYP2C9*2 and CYP2C9*3 polymorphisms, gave no significant associations for neither VKORC1*3, VKORC1*4 nor CYP4F2 (1347 C > T). In conclusion, in patients with myocardial infarction, the individual contribution to warfarin dose requirements from VKORC1*3, VKORC1*4, and CYP4F2 (1347 C > T) polymorphisms was negligible. Our results indicate that pharmacogenetic testing for VKORC1*2, CYP2C9*2 and CYP2C9*3 is more informative regarding warfarin dose requirements than testing for VKORC1*3, VKORC1*4, and CYP4F2 (1347 C > T) polymorphisms.
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Extending and evaluating a warfarin dosing algorithm that includes CYP4F2 and pooled rare variants of CYP2C9. Pharmacogenet Genomics 2010; 20:407-13. [PMID: 20442691 DOI: 10.1097/fpc.0b013e328338bac2] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Warfarin dosing remains challenging because of its narrow therapeutic window and large variability in dose response. We sought to analyze new factors involved in its dosing and to evaluate eight dosing algorithms, including two developed by the International Warfarin Pharmacogenetics Consortium (IWPC). METHODS we enrolled 108 patients on chronic warfarin therapy and obtained complete clinical and pharmacy records; we genotyped single nucleotide polymorphisms relevant to the VKORC1, CYP2C9, and CYP4F2 genes using integrated fluidic circuits made by Fluidigm. RESULTS When applying the IWPC pharmacogenetic algorithm to our cohort of patients, the percentage of patients within 1 mg/d of the therapeutic warfarin dose increases from 54% to 63% using clinical factors only, or from 38% using a fixed-dose approach. CYP4F2 adds 4% to the fraction of the variability in dose (R) explained by the IWPC pharmacogenetic algorithm (P<0.05). Importantly, we show that pooling rare variants substantially increases the R for CYP2C9 (rare variants: P=0.0065, R=6%; common variants: P=0.0034, R=7%; rare and common variants: P=0.00018; R=12%), indicating that relatively rare variants not genotyped in genome-wide association studies may be important. In addition, the IWPC pharmacogenetic algorithm and the Gage (2008) algorithm perform best (IWPC: R=50%; Gage: R=49%), and all pharmacogenetic algorithms outperform the IWPC clinical equation (R=22%). VKORC1 and CYP2C9 genotypes did not affect long-term variability in dose. Finally, the Fluidigm platform, a novel warfarin genotyping method, showed 99.65% concordance between different operators and instruments. CONCLUSION CYP4F2 and pooled rare variants of CYP2C9 significantly improve the ability to estimate warfarin dose.
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Orsi FA, Annichino Bizzacchi JM, de Paula EV, Ozelo MC, Langley MR, Weck KE. VKORC1 V66M mutation in African Brazilian patients resistant to oral anticoagulant therapy. Thromb Res 2010; 126:e206-10. [PMID: 20615525 DOI: 10.1016/j.thromres.2010.06.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/12/2010] [Accepted: 06/07/2010] [Indexed: 11/28/2022]
Abstract
Warfarin-based anticoagulant therapy is associated with large variability in dose response. Genetic variability in the VKORC1 and CYP2C9 genes is associated with increased warfarin sensitivity. In addition, rare coding region mutations in VKORC1 have been associated with resistance to warfarin. VKORC1 and CYP2C9 variability associated with altered warfarin response is less well characterized in African and mixed-raced populations such as Brazilians. To determine genetic variability associated with altered warfarin response among Brazilian patients, sixty-two adult patients with extreme resistance or sensitivity to warfarin were genotyped for variants in CYP2C9 and VKORC1. Of the 51 patients on low doses of warfarin, the VKORC1--1639 (3673) G>A polymorphism associated with warfarin sensitivity was present in 48 (94.1%), including 97% of Caucasians, 82% of African-descent patients, and all 7 (100%) patients of Indian descent. Additionally, 52.9% of warfarin sensitive patients had at least one CYP2C9*2 or CYP2C9*3 decreased metabolism allele, 63.6% of Caucasians and 54% of African-descent patients. Of the 11 patients on high doses of warfarin, sequencing of VKORC1 revealed a nonsynonymous V66M mutation in two warfarin resistant patients, both of African-descent. Brazilian patients requiring low doses of warfarin have a high frequency of VKORC1 and CYP2C9 variants associated with warfarin sensitivity. The presence of the rare VKORC1 V66M in two warfarin high dose outlier patients implies that this variant may be more frequent among African Brazilians and has implications for future warfarin studies in other populations of African descent.
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Affiliation(s)
- Fernanda A Orsi
- Hematology and Hemotherapy Center, State University of Campinas, Brazil.
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Pharmacogénétique et antivitamine K aujourd’hui : un débat ouvert. Rev Med Interne 2010; 31:361-8. [DOI: 10.1016/j.revmed.2009.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 06/03/2009] [Accepted: 07/08/2009] [Indexed: 11/22/2022]
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Lezhava A, Ishidao T, Ishizu Y, Naito K, Hanami T, Katayama A, Kogo Y, Soma T, Ikeda S, Murakami K, Nogawa C, Itoh M, Mitani Y, Harbers M, Okamoto A, Hayashizaki Y. Exciton Primer-mediated SNP detection in SmartAmp2 reactions. Hum Mutat 2010; 31:208-17. [PMID: 20052755 DOI: 10.1002/humu.21177] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Most commonly used intercalating fluorescent dyes in DNA detection are lacking any sequence specificity, whereas so-called Exciton Primers can overcome this limitation by functioning as "sequence-specific dyes." After hybridization to complementary sequences, the fluorescence of Exciton Primers provides sequence-specific signals for real-time monitoring of amplification reactions. Applied to the SmartAmp2 mutation detection process, Exciton Primers show high signal strength with low background leading to a superior specificity and sensitivity compared to SYBR Green I. Signal strength can be further enhanced using multiple dyes within one Exciton Primer or use of multiple Exciton Primers in the same amplification reaction. Here we demonstrate the use of Exciton Primers for genotyping a single nucleotide polymorphism (SNP) in the VKORC1 locus (-1639G>A) relevant for Warfarin dosing as an example for Exciton Primers mediated genotyping by SmartAmp2. The genotyping assay can use only one labeled Exciton Primer for endpoint detection, or simultaneously by real-time monitoring detect wild-type and mutant alleles in a one-tube reaction using two Exciton Primers having different dyes. Working directly from blood samples, Exciton Primer mediated genotyping by SmartAmp2 offers superior solutions for rapid point-of-care testing.
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Affiliation(s)
- Alexander Lezhava
- Technology Development Unit, Omics Science Center (OSC), RIKEN Yokohama Institute, Kanagawa, Japan
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Puehringer H, Loreth RM, Klose G, Schreyer B, Krugluger W, Schneider B, Oberkanins C. VKORC1 -1639G>A and CYP2C9*3 are the major genetic predictors of phenprocoumon dose requirement. Eur J Clin Pharmacol 2010; 66:591-8. [PMID: 20376629 DOI: 10.1007/s00228-010-0809-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Accepted: 02/24/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE Phenprocoumon, similar to other coumarin-derived anticoagulants, is associated with a large variation in the individual dose requirement to achieve stable anticoagulation. Polymorphisms in the vitamin K epoxide reductase complex subunit 1 (VKORC1) and the liver enzyme cytochrome P450 2C9 (CYP2C9) effectively account for the variability in warfarin and acenocoumarol response but are less well-defined pharmacogenetic predictors in phenprocoumon therapy. METHODS A retrospective study was performed on 185 outpatients attending anticoagulation clinics in Austria and Germany. These patients were genotyped for the VKORC1 -1639G>A and 3730G>A polymorphisms as well as for the CYP2C9 *2 and *3 polymorphisms using a reverse hybridisation-based teststrip assay. RESULTS The VKORC1 -1639A allele, which was present at a frequency of 41.4% in the study cohort, significantly reduced the mean weekly phenprocoumon dose by 3 mg (19%) in the heterozygous and by 6.7 mg (43%) in the homozygous state compared to wild-type carriers (15.5 +/- 6.8 mg, p < 0.0001). A stepwise multiple regression analysis revealed that VKORC1 -1639G>A, age and CYP2C9*3 were the major independent determinants of phenprocoumon dose, accounting for 14.2, 9.1 and 4.7% of its variability, respectively (p </= 0.0007). The CYP2C9*2 polymorphism had a marginal influence (1.4%) and failed to reach statistical significance (p = 0.062). The VKORC1 3730G>A genotype had no additional predictive power for individual dose variability. CONCLUSION Similar to warfarin and acenocoumarol, the VKORC1 -1639G>A polymorphism had the highest impact on the maintenance dose of phenprocoumon. The factor age was the second most important predictor and explained a greater percentage of the variability than CYP2C9 genotype.
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Affiliation(s)
- Helene Puehringer
- ViennaLab Diagnostics GmbH, Gaudenzdorfer Guertel 43-45, 1120, Vienna, Austria.
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Rombouts EK, Rosendaal FR, Van Der Meer FJM. Influence of dietary vitamin K intake on subtherapeutic oral anticoagulant therapy. Br J Haematol 2010; 149:598-605. [DOI: 10.1111/j.1365-2141.2010.08108.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Sunder-Plassmann R, Mannhalter C. Pharmacogenetics guided anticoagulation. Clin Chem Lab Med 2010; 48 Suppl 1:S119-27. [DOI: 10.1515/cclm.2010.370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Sipeky C, Csongei V, Jaromi L, Safrany E, Polgar N, Lakner L, Szabo M, Takacs I, Melegh B. Vitamin K epoxide reductase complex 1 (VKORC1) haplotypes in healthy Hungarian and Roma population samples. Pharmacogenomics 2009; 10:1025-32. [PMID: 19530970 DOI: 10.2217/pgs.09.46] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The aim of this work was to determine the VKORC1 haplotype profile in healthy Hungarian and Roma population samples, and to compare our data with other selected populations. Using haplotype tagging SNPs (G-1639A, G9041A and C6009T), we characterized Hungarian (n = 510) and Roma (n = 451) population samples with regard to VKORC1*1, *2, *3 and *4 haplotypes. In the Hungarian samples, the VKORC1*1, *2, *3 and *4 haplotypes accounted for 3, 39, 37 and 21%, respectively and by contrast, in the Roma population samples the VKORC1 variants were 5, 30, 46 and 19%, respectively. Comparing the genotypes of Roma and Hungarian populations, difference was found in the *2/*2 (6.87 vs 13.5%), *2/*4 (13.9 vs 19.2%) and *3*3 (21.9 vs 13.7%) VKORC1 haplotype combinations. Comparing each group with the others, and our data with findings published previously by other groups, the VKORC1 genetic profile in Hungarians was more similar to European Caucasians and Americans with European descent than to Roma samples. Clear differences could be detected between Roma versus Hungarians and European or American Caucasians; the Roma population had only minor similarities with data from India.
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Affiliation(s)
- Csilla Sipeky
- University of Pecs, Department of Medical Genetics and Child Development, H-7624 Pecs, Szigeti 12, Hungary
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Genotypes Associated With Reduced Activity of VKORC1 and CYP2C9 and Their Modification of Acenocoumarol Anticoagulation During the Initial Treatment Period. Clin Pharmacol Ther 2009; 85:379-86. [DOI: 10.1038/clpt.2008.294] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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