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Vorthunju Nakhonsri,1 Shobana John,2,3 Hathaichanok Panumasmontol,4,5 Manassanan Jantorn,4,5 Pongpipat Chanthot,4,5 Nuntachai Hanpramukkun,6 Supaporn Meelarp,7 Chonlaphat Sukasem,2,3 Sissades Tongsima,1 Sukhontha Hasatsri,4 Abhisit Prawang,8 Thanawat Thaingtamtanha,9,10 Natchaya Vanwong,11,12 Chalirmporn Atasilp,13 Monpat Chamnanphon,14 Pimonpan Jinda,2,3 Patompong Satapornpong4,5 1National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand; 2Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center (SDMC), Ramathibodi Hospital, Bangkok, Thailand; 4Division of General Pharmacy Practice, Department of Pharmaceutical Care, College of Pharmacy, Rangsit University, Pathum Thani, Thailand; 5Excellence Pharmacogenomics and Precision Medicine Centre, College of Pharmacy, Rangsit University, Pathum Thani, Thailand; 6Division of Pharmaceutical Technology, Department of Industrial Pharmacy, College of Pharmacy, Rangsit University, Pathum Thani, Thailand; 7Ounjai Medical Clinic, Bangsue, Bangkok, Thailand; 8Division of Pharmacy Practice, Department of Pharmaceutical Care, College of Pharmacy, Rangsit University, Pathum Thani, Thailand; 9Department of Chemistry and Biology, University of Siegen, Siegen, Germany; 10Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada; 11Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand; 12Department of Clinical Chemistry, SYstems Neuroscience of Autism & PSychiatric Disorders (SYNAPS) Research Unit, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand; 13Chulabhorn International College of Medicine, Thammasat University, Pathumthani, Thailand; 14Department of Pathology, Faculty of Medicine, Srinakharinwirot University, Nakornnayok, ThailandCorrespondence: Patompong Satapornpong, Director of Excellence Pharmacogenomics and Precision Medicine Centre, College of Pharmacy, Rangsit University, Pathum Thani, Thailand, Tel +66- 2-791-6000 1420, Fax +66- 2-791-6000 1403, Email patompong.s@rsu.ac.thIntroduction: CYP2C19 plays a major role in the metabolism of various drugs. The most common genetic variants were the CYP2C19&ast;2 and &ast;3 alleles (rs4244285 and rs4986893, non-functional variants). In previous studies, we found that genetic polymorphisms in CYP2C19 variants influenced the active metabolites of clopidogrel and caused major adverse cardiovascular and cerebrovascular effects. However, the distribution of CYP2C19 varies among ethnic groups and according to adverse drug reactions. This study aimed to investigate the frequency of CYP2C19 genetic polymorphisms in the Thai population and analyze the differences in the frequency of CYP2C19 genetic polymorphisms between Thai and other populations.Methods: This study enrolled 211 unrelated healthy Thai individuals in total. We performed a real-time polymerase chain reaction to genotype CYP2C19&ast;2 (681G > A) and CYP2C19&ast;3 (636G > A).Results: In the Thai population, the CYP2C19&ast;1 allele was the most prevalent at 70.14%, while the CYP2C19&ast;2 and &ast;3 alleles were found at frequencies of 25.36% and 4.50%, respectively. Conversely, the CYP2C19&ast;3 allele was not detected in Caucasian, Hispanic, African, Italian, Macedonian, Tanzanian, or North Indian populations. The phenotypic profile of this gene revealed that the frequency of intermediate metabolizers (IMs) is nearly equal to that of extensive metabolizers (EMs), at 42.65% and 48.82% respectively, with genotypes &ast;1/&ast;2 (36.02%) and &ast;1/&ast;3 (6.63%). Likewise, poor metabolizers (PMs) with genotypes &ast;2/&ast;2 (6.16%), &ast;2/&ast;3 (2.37%), and &ast;3/&ast;3 (< 1%) are more prevalent in our population as well.Conclusion: The distribution of CYP2C19 genotype and phenotype influenced by non-functional alleles has potential as a pharmacogenomics biomarker for precision medicine and is dependent on an ethnic-specific genetic variation database.Keywords: CYP2C19 gene, genetic diversity, Thai population, interethnic differences

Saowalak Turongkaravee,1 Naiyana Praditsitthikorn,2 Thundon Ngamprasertchai,3 Jiraphun Jittikoon,4 Surakameth Mahasirimongkol,5 Chonlaphat Sukasem,6– 9 Wanvisa Udomsinprasert,4 Olivia Wu,10 Usa Chaikledkaew11,12 1Social, Economic and Administrative Pharmacy (SEAP) Graduate Program, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand; 2Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand; 3Department of Clinical Tropical Medicine, Faculty of Tropical Medicine; Mahidol University, Bangkok, Thailand; 4Department of Biochemistry, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand; 5Department of Medical Sciences, Medical Genetics Center, Medical Life Sciences Institute, Ministry of Public Health, Nonthaburi, Thailand; 6Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 7Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center (SDMC), Ramathibodi Hospital, Bangkok, Thailand; 8Pharmacogenomics and Precision Medicine, The Preventive Genomics & Family Check-Up Services Center, Bumrungrad International Hospital, Bangkok, Thailand; 9MRC Centre for Drug Safety Science, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 3GL, UK; 10Health Economics and Health Technology Assessment (HEHTA), Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK; 11Social and Administrative Pharmacy Division, Department of Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand; 12Mahidol University Health Technology Assessment (MUHTA) Graduate Program, Mahidol University, Bangkok, ThailandCorrespondence: Usa Chaikledkaew, Social and Administrative Pharmacy Division, Department of Pharmacy, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhaya Road, Rajathevi, Bangkok, 10400, Thailand, Tel +662-644-8679 ext 5317, Fax +662-644-8694, Email usa.chi@mahidol.ac.thPurpose: Pharmacogenetics (PGx) testing is one of the methods for determining whether individuals are at risk of adverse drug reactions (ADRs). It has been reported that multiple-PGx testing, a sequencing technology, has a higher predictive value than single-PGx testing. Therefore, this study aimed to determine the most cost-effective PGx testing strategies for preventing drug-induced serious ADRs in human immunodeficiency virus (HIV)-infected patients.Patients and Methods: Potential strategies, including 1) single-PGx esting (ie, HLA-B&ast;57:01 testing before prescribing abacavir, HLA-B&ast;13:01 testing before prescribing co-trimoxazole and dapsone, and NAT2 testing before prescribing isoniazid) and 2) multiple-PGx testing as a combination of four single-gene PGx tests in one panel, were all compared to no PGx testing (current practice). To evaluate total cost in Thai baht (THB) and quality-adjusted life years (QALYs) for each strategy-based approach to a societal perspective, a hybrid decision tree and Markov model was constructed. Incremental cost-effectiveness ratios (ICERs) were estimated. Uncertainty, threshold, and scenario analyses were all performed.Results: Before prescribing HIV therapy, providing single or multiple-PGx testing might save roughly 68 serious ADRs per year, and the number needed to screen (NNS) to avoid one serious ADR was 40. Consequently, approximately 35% and 40% of the cost of ADR treatment could be avoided by the implementation of single- and multiple-PGx testing, respectively. Compared with no PGx testing strategy, the ICERs were 146,319 THB/QALY gained for single-PGx testing and 152,014 THB/QALY gained for multiple-PGx testing. Moreover, the probability of multiple-PGx testing being cost-effective was 45% at the Thai willingness to pay threshold of 160,000 THB per QALY. Threshold analyses showed that multiple-PGx testing remained cost-effective under the range of cost, sensitivity at 0.95– 1.00 and specificity at 0.98– 1.00.Conclusion: Single and multiple-PGx testing might be cost-effective options for reducing the incidence of drug-induced serious ADRs in people living with HIV.Keywords: pharmacogenetic, adverse drug reactions, HIV, cost-utility analysis, economic evaluation

Natchaya Vanwong,1,2 Sayanit Tipnoppanon,1 Chalitpon Na Nakorn,3 Pornpen Srisawasdi,4 Punyanuch Rodcharoen,4 Sadeep Medhasi,5 Pajaree Chariyavilaskul,2,6,7 Sarawut Siwamogsatham,2,8,9 Yongkasem Vorasettakarnkij,2,9 Chonlaphat Sukasem10– 12 1Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand; 2Cardiovascular Precision Medicine Research Group, Special Task Force of Activating Research (STAR), Chulalongkorn University, Bangkok, Thailand; 3Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Songkhla, Thailand; 4Division of Clinical Chemistry, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 5Department of Transfusion Medicine and Clinical Microbiology, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand; 6Department of Pharmacology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 7Clinical Pharmacokinetics and Pharmacogenomics Research Unit, Chulalongkorn University, Bangkok, Thailand; 8Chula Clinical Research Center, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 9Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 10Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 11Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center (SDMC), Ramathibodi Hospital, Bangkok, Thailand; 12Pharmacogenomics and Precision Medicine, The Preventive Genomics & Family Check-up Services Center, Bumrungrad International Hospital, Bangkok, ThailandCorrespondence: Chonlaphat Sukasem, Division of Pharmacogenetics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand, Tel +66-2-200-4331, Fax +66-2-200-4332, Email chonlaphat.suk@mahidol.ac.thPurpose: Statins are increasingly widely used in the primary and secondary prevention of cardiovascular disease. However, there is an inter-individual variation in statin response among patients. The study aims to determine the association between genetic variations in drug-metabolizing enzyme and transporter (DMET) genes and lipid-lowering response to a statin in Thai patients with hyperlipidemia.Patients and Methods: Seventy-nine patients who received statin at steady-state concentrations were recruited. Serum lipid profile was measured at baseline and repeated after 4-month on a statin regimen. The genotype profile of 1936 DMET markers was obtained using Affymetrix DMET Plus genotyping microarrays.Results: In this DMET microarray platform, five variants; SLCO1B3 (rs4149117, rs7311358, and rs2053098), QPRT (rs13331798), and SLC10A2 (rs188096) showed a suggestive association with LDL-cholesterol-lowering response. HDL-cholesterol-lowering responses were found to be related to CYP7A1 gene variant (rs12542233). Seven variants, SLCO1B3 (rs4149117, rs7311358, and rs2053098); SULT1E1 (rs3736599 and rs3822172); and ABCB11 (rs4148768 and rs3770603), were associated with the total cholesterol-lowering response. One variant of the ABCB4 gene (rs2109505) was significantly associated with triglyceride-lowering response.Conclusion: This pharmacogenomic study identifies new genetic variants of DMET genes that are associated with the lipid-lowering response to statins. Genetic polymorphisms in DMET genes may impact the pharmacokinetics and lipid-lowering response to statin. The validation studies confirmations are needed in future pharmacogenomic studies.Keywords: drug-metabolizing enzymes, drug transporters, gene polymorphisms, statin

Monpat Chamnanphon,1,2,&ast; Rattanaporn Sukprasong,3,4,&ast; Andrea Gaedigk,5,6 Weerawat Manosuthi,7 Pajaree Chariyavilaskul,2 Supeecha Wittayalertpanya,2 Napatrupron Koomdee,3,4 Thawinee Jantararoungtong,3,4 Apichaya Puangpetch,3,4 Chonlaphat Sukasem3,4 1Department of Pathology, Faculty of Medicine, Srinakharinwirot University, Nakornnayok, Thailand; 2Clinical Pharmacokinetics and Pharmacogenomics Research Unit, Department of Pharmacology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 3Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 4Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center (SDMC), Ramathibodi Hospital, Bangkok, Thailand; 5Division of Clinical Pharmacology, Toxicology & Therapeutic Innovation, Children’s Mercy Kansas City, Kansas City, MO, USA; 6School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA; 7Bamrasnaradura Infectious Diseases Institute, Ministry of Public Health, Nonthaburi, Thailand&ast;These authors contributed equally to this workCorrespondence: Chonlaphat SukasemDivision of Pharmacogenetics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, ThailandTel +66-2-200-4331Fax +66-2-200-4332Email chonlaphat.suk@mahidol.ac.thPurpose: Plasma efavirenz (EFV) concentrations within therapeutic levels are essential to successfully treat patients suffering from human immunodeficiency virus (HIV) type 1. In addition to the drug-metabolizing enzyme CYP2B6, other phase II drug-metabolizing enzymes and transporters may have an important role in the pharmacokinetics of EFV. Thus, the influence of phase II drug-metabolizing enzymes and drug transporters on plasma EFV levels was investigated in Thai HIV patients receiving EFV.Patients and Methods: Genotyping was performed by TaqMan® real-time PCR in 149 HIV-infected Thai adults, and plasma efavirenz concentration was measured by a validated high-performance liquid chromatography in 12 hours after dosing steady-state plasma samples at week 12 and 24.Results: Patients with three or more copies of SULT1A1 had significantly lower median plasma EFV concentrations than those carrying two copies at week 12 (p=0.046) and SULT1A1&ast;2 (c.638G>A) carriers had significantly lower median plasma EFV concentrations compared to those not carrying the variant at week 24 (p=0.048). However, no significant association was found after adjusting for CYP2B6 genotype.Conclusion: Genetic variation in a combination of SULT1A1&ast;2 and SULT1A1 copy number may contribute to variability in EFV metabolism and thereby may impact drug response. The influence of a combination between the SULT1A1 and CYP2B6 genotype on EFV pharmacokinetics should be further investigated in a larger study population.Keywords: phase II drug-metabolizing enzymes, transporter genes, efavirenz, HIV-1, Thai

Tran Thu Ha Pham,1 Quang Binh Tran,2 Chonlaphat Sukasem,3– 5 Van Dinh Nguyen,6,7 Chi Hieu Chu,8 Thi Quynh Nga Do,9 Ngoc Phuong Mai Tran,9 Thanh Huong Phung1 1Hanoi University of Pharmacy, Hanoi, Vietnam; 2National Institute of Nutrition, Hanoi, Vietnam; 3Division of Pharmacogenomics and Personalized Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 4Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center (SDMC), Ramathibodi Hospital, Bangkok, Thailand; 5The Thai Severe Cutaneous Adverse Drug Reaction (THAI-SCAR) Research Group, Bangkok, Thailand; 6Respiratory, Allergy and Clinical Immunology Unit, Internal Medicine Department, Vinmec Times City International Hospital, Vinmec Healthcare System, Hanoi, Vietnam; 7College of Health Sciences, VinUniversity, Hanoi, Vietnam; 8Center of Allergology and Clinical Immunology, Bach Mai Hospital, Hanoi, Vietnam; 9National Institute of Hygiene and Epidemiology, Hanoi, VietnamCorrespondence: Thanh Huong Phung; Quang Binh Tran Tel +84 904112588; +84 904470844Email huongpt@hup.edu.vn; tranquangbinh@dinhduong.org.vnBackground: Allopurinol, a common anti-hyperuricemia drug, is well known as an inducer of severe cutaneous adverse drug reactions (SCARs). One of the most well-defined risk factors of allopurinol-induced SCARs is the presence of polymorphic alleles of human leukocyte antigen (HLA) genes, such as HLA-B*58:01 and HLA-C*03:02 alleles. There is no commercial test or published in-house protocol for the specific detection of the HLA-C*03:02 allele. In this article, we established for the first time a simple allele-specific (AS) PCR method to identify HLA-C*03:02 allele carriers, and at the same time, determine their zygosities.Methods: A two-step AS-PCR protocol, using four primer sets, was designed to specifically amplify and differentiate the HLA-C*03:02 allele from 17 other HLA-C alleles found in Vietnamese people. The protocol was validated with PCR-sequencing-based typing (SBT) of 100 samples of unknown genotypes.Results: The PCR protocol can detect the HLA-C*03:02 allele and determine the zygosity. The results of this protocol were highly consistent with those of the SBT (ĸ = 0.98, p < 0.001). Regarding the specific detection of the HLA-C*03:02 allele, the PCR protocol had a sensitivity of 100% (95% CI: 91.61– 100%) and specificity of 98.3% (95% CI: 90.9– 99.7%). The protocol was used to determine the distribution of the HLA-C*03:02 allele in 810 unrelated Vietnamese Kinh people, 14.2% of which were HLA-C*03:02 carriers, the allele frequency was 7.5%.Conclusion: A novel AS-PCR protocol with a sensitivity of 100% for the detection of the HLA-C*03:02 allele was established. The protocol can be used for personalized treatment with allopurinol in order to minimize the risk of SCARs in Vietnamese people as well as in other Asian populations with similar genetic characteristics.Keywords: severe cutaneous adverse reactions, HLA-C*03:02, allopurinol, HLA genotyping, AS-PCR

Pornpen Srisawasdi,1 Punyanuch Rodcharoen,1 Somlak Vanavanan,1 Anchalee Chittamma,1 Chonlaphat Sukasem,2 Chalitpon Na nakorn,2 Charungthai Dejthevaporn,3 Martin H Kroll4 1Division of Clinical Chemistry, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 2Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 4Quest Diagnostics, Secaucus, NJ 07094, United States of AmericaCorrespondence: Pornpen Srisawasdi Division of Clinical Chemistry, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Rama VI Road, Ratchathewi, Bangkok 10400, ThailandTel +66-2-201-0008Fax +66-2-354-7266Email srisawasdip@yahoo.comObjective: Patients treated with statins for dyslipidemia may still have a residual risk of atherosclerotic cardiovascular disease (ASCVD). To determine whether genetic variants in the cholesteryl ester transport protein (CETP), rs3764261 (C>A), rs708272 (G>A), and rs12149545 (G>A) affect ASCVD risk, we studied the association of these variants with dyslipidemia in statin-treated patients.Patients and Methods: We included 299 adult Thai patients treated with a statin (95 men and 204 women). Genotyping was performed by conducting a TaqMan real-time polymerase chain reaction-based analysis. We used logistic regression models adjusted for potential confounders of age, body mass index, blood pressure, insulin resistance, and statin dosage to analyze the association between CETP variants and atherogenic lipoprotein patterns.Results: CETP polymorphisms of rs3764261 and rs708272, but not rs12149545, were significantly associated with high-density lipoprotein cholesterol (HDL-C), apoA-I, triglycerides, very low-density lipoprotein (VLDL)-C, and large LDL (LDL1-C) levels as well as mean LDL particle size (all p < 0.020). However, no significant difference was observed in total cholesterol, LDL-C, or apoB levels by CETP variants. Regardless of sex, the combination of rs3764261 (CC genotype) and rs708272 (GG or GA genotypes) showed a stronger association with atherogenic dyslipidemia, including features of decreased HDL-C, elevated triglycerides, and LDL subclass pattern B (odds ratio [OR] =  2.99, 95% confidence interval [CI]: 1.78– 5.02) compared with the single variant rs3764261 (OR =  2.11, 95% CI: 1.27– 3.50) or rs708272 (OR =  2.12, 95% CI: 1.29– 3.49).Conclusion: The polymorphisms of CETP rs3764261 (CC genotype) and rs708272 (GG and GA genotypes) may have a higher susceptibility to atherogenic dyslipidemia. Testing for CETP rs3764261 and rs708272 may serve as a surrogate marker for lipid management in statin-treated patients, which may help individualize treatment for reducing the residual risk of ASCVD.Keywords: residual atherosclerotic risk, statin treatment, cholesteryl ester transport protein, genetic polymorphisms, genetic risk

Monpat Chamnanphon,1 Sorawit Wainipitapong,2 Teeravut Wiwattarangkul,3 Phenphichcha Chuchuen,2 Kunathip Nissaipan,1,4 Weeraya Phaisal,1,4 Sookjaroen Tangwongchai,2 Chonlaphat Sukasem,5 Supeecha Wittayalertpanya,1,4 Andrea Gaedigk,6 Daruj Aniwattanapong,2 Pajaree Chariyavilaskul1,4 1Clinical Pharmacokinetics and Pharmacogenomics Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 2Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 3Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 4Department of Pharmacology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; 5Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 6Division of Clinical Pharmacology, Toxicology & Therapeutic Innovation, Children’s Mercy Kansas City and School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USACorrespondence: Daruj AniwattanapongDepartment of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, ThailandTel +66 2 256 4298Email daruj.a@chula.ac.thPajaree ChariyavilaskulDepartment of Pharmacology, Faculty of Medicine, Chulalongkorn University, Bangkok, ThailandTel +66 2 256 4481 ext. 3020Email pajaree.l@chula.ac.thPurpose: Donepezil, a drug frequently used to treat dementia, is mainly metabolized by cytochrome P450 2D6 (CYP2D6). This study investigated the relationships between CYP2D6 genotype and activity scores as well as predicted phenotype of plasma donepezil concentrations in 86 Thai dementia participants.Materials and Methods: CYP2D6 was genotyped using bead-chip technology (Luminex xTAG® v.3). Steady-state trough plasma donepezil concentrations were measured using high-performance liquid chromatography.Results: Sixteen genotypes were found but the most frequent genotypes detected among our participants were CYP2D6*10/*10 (27.9%) and *1/*10 (26.7%). One-third of the participants had an activity score of 1.25 which predicted that they were normal metabolizers. The overall median (interquartile range) of plasma donepezil concentration was 51.20 (32.59– 87.24) ng/mL. Normal metabolizers (NMs) had lower plasma donepezil concentrations compared to intermediate metabolizers (IMs) (41.15 (28.44– 67.65) ng/mL vs 61.95 (35.25– 97.00) ng/mL). Multivariate analysis showed that CYP2D6 activity score (r2 = 0.50) and the predicted phenotype (independent of dose) could predict the plasma donepezil concentration (r2 = 0.49).Conclusion: Plasma donepezil concentration in NMs was lower compared to IMs. Additional studies with larger sample size and use of next-generation sequencing as well as its outcomes are warranted to confirm the benefit of using pharmacogenetic-guided treatment for donepezil.Keywords: CYP2D6, Luminex xTAG®, donepezil, dementia, pharmacogenetics

Monpat Chamnanphon, 1 Andrea Gaedigk, 2 Apichaya Puangpetch, 3, 4 Ekawat Pasomsub, 5 Wasun Chantratita, 6 Rhea J Longley, 7, 8 Jetsumon Sattabongkot, 7 Pajaree Chariyavilaskul, 1 Chonlaphat Sukasem 3, 4 1Clinical Pharmacokinetics and Pharmacogenomics Research Unit, Department of Pharmacology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; 2Division of Clinical Pharmacology, Toxicology & Therapeutic Innovation, Children’s Mercy Kansas City, and School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA; 3Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 4Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center (SDMC), Ramathibodi Hospital, Bangkok, Thailand; 5Division of Virology, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 6Center of Genomics Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 7Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; 8Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC, AustraliaCorrespondence: Chonlaphat SukasemDivision of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, ThailandTel +66 22004330-2Fax +66 22004332Email chonlaphat.suk@mahidol.ac.thPurpose: Pharmacogenes have an influence on biotransformation pathway and clinical outcome of primaquine and chloroquine which are often prescribed to treat Plasmodium vivax infection. Genetic variation may impact enzyme activity and/or transporter function and thereby contribute to relapse. The aim of the study was to assess allele, genotype frequencies and the association between pharmacogenes variation and primaquine response in Thai patients infected with Plasmodium vivax.Patients and Methods: Fifty-one patients were genotyped for 74 variants in 18 genes by Sequenom MassARRAY® and Taqman® SNP Real-Time PCR.Results: SNP frequencies were not significantly different between relapse (n=4) and non-relapse (n=47) patients. However, the CYP2C19 c.681G>A, the frequency of the A-allele that defines the non-functional CYP2C19*2 haplotype was significantly higher compared to the G-allele (OR=5.14, p=0.021). Patients heterozygous for ABCG2 c.421C>A had a higher odds ratio (OR=8.75, p=0.071) and the frequency of the G-allele of UGT2B7 c.372G>A was higher compared to the A-allele (OR=3.75, p=0.081). CYP2C19, ABCG2 and UGT2B7 emerged as potential high priority genes.Conclusion: Decreased activity of CYP2C19, ABCG2 and UGT2B7 in combination with CYP2D6 intermediate or poor metabolizer status may expose patients to a higher risk of Plasmodium vivax relapse. Further investigations are warranted to substantiate these findings.Keywords: primaquine, chloroquine, Plasmodium vivax, relapse, pharmacogenes

Apichaya Puangpetch,1 Pornpen Srisawasdi,2 Weerapon Unaharassamee,3 Napa Jiratjintana,3 Somlak Vanavanan,2 Suweejuk Punprasit,2 Chalitpon Na Nakorn,1 Chonlaphat Sukasem,1 Martin H Kroll41Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 2Division of Clinical Chemistry, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Department of Psychiatry, Somdet Chaopraya Institute of Psychiatry, Bangkok, Thailand; 4Quest Diagnostics, Secaucus, NJ 07094, USAObjective: To determine whether genetic polymorphisms related to pharmacodynamics with metabolic adverse effects, namely leptin promoter (LEP) rs7799039, leptin receptor rs1137101, dopamine D2 rs4436578, serotonin 5-HT2A rs6313, and serotonin 5-HT2C rs518147 and rs12836771, are associated with hyperglycemia induced by risperidone or clozapine in adult Thai patients with psychosis.Methods: A total of 180 patients treated with risperidone-based (n=130) or clozapine-based (n=50) regimens were included in this study. Blood samples were analyzed for genotyping of the candidate genes and biochemical testing. Genotyping was performed by conducting a TaqMan real-time polymerase chain reaction-based analysis.Results: The prevalence of hyperglycemia was higher in patients receiving clozapine (64.0%) than in those receiving risperidone (30.8%). Among the candidate genes, only the LEP rs7799039 polymorphism demonstrated a significant association with hyperglycemia (χ2=9.879, P=0.008) in patients treated with risperidone; patients with the AA genotype had the highest risk (41.1%), followed by those with AG (20.8%) and GG (0%) genotypes. Using the recessive genetic model (AA vs AG + GG), the odds ratio and 95% CI were 3.28 and 1.44 −7.50, respectively. None of the genes were associated with hyperglycemia in patients treated with clozapine. A binary logistic regression revealed that the LEP rs7799039 polymorphism demonstrated a significant association with hyperglycemia, independent of body-mass index (BMI) in patients receiving risperidone; the odds ratio (95% CI) was 3.188 (1.399–7.262), P=0.006. By contrast, none of the pharmacodynamic genetic factors, except for BMI, were significantly associated with hyperglycemia in patients receiving clozapine.Conclusion: The risk of type 2 diabetes mellitus is associated with the LEP rs7799039 polymorphism in Thai adults receiving risperidone but not in those receiving clozapine. Clarifying underlying mechanisms and risk of hyperglycemia provides an opportunity to prevent impaired glucose metabolism in patients receiving risperidone or clozapine.Keywords: atypical antipsychotics, leptin promoter, leptin receptor, dopamine D2, serotonin 5-HT2A, serotonin 5-HT2C, diabetes mellitus

Apichaya Puangpetch,1 Natchaya Vanwong,1 Nopphadol Nuntamool,2 Yaowaluck Hongkaew,1 Monpat Chamnanphon,1 Chonlaphat Sukasem1 1Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, 2Molecular Medicine, Faculty of Science, Mahidol University, Bangkok, Thailand Abstract: Cytochrome P450 enzyme especially CYP2D6 plays a major role in biotransformation. The interindividual variations of treatment response and toxicity are influenced by the polymorphisms of this enzyme. This review emphasizes the effect of CYP2D6 polymorphisms in risperidone treatment in terms of basic knowledge, pharmacogenetics, effectiveness, adverse events, and clinical practice. Although the previous studies showed different results, the effective responses in risperidone treatment depend on the CYP2D6 polymorphisms. Several studies suggested that CYP2D6 polymorphisms were associated with plasma concentration of risperidone, 9-hydroxyrisperidone, and active moiety but did not impact on clinical outcomes. In addition, CYP2D6 poor metabolizer showed more serious adverse events such as weight gain and prolactin than other predicted phenotype groups. The knowledge of pharmacogenomics of CYP2D6 in risperidone treatment is increasing, and it can be used for the development of personalized medication in term of genetic-based dose recommendation. Moreover, the effects of many factors in risperidone treatment are still being investigated. Both the CYP2D6 genotyping and therapeutic drug monitoring are the important steps to complement the genetic-based risperidone treatment. Keywords: CYP2D6, risperidone, polymorphisms, adverse drug reaction, pharmacogenetics, pharmacokinetics, pharmacodynamics

Asalaysa Bushyakanist,1 Apichaya Puangpetch,2,3 Chonlaphat Sukasem,2,3 Sasisopin Kiertiburanakul11Department of Medicine, 2Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 3Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center (SDMC), Ramathibodi Hospital, Bangkok, ThailandObjectives: The objectives of this study were to describe the use of pharmacogenetics in clinical practice for the treatment of individuals with human immunodeficiency virus (HIV) infection and to determine the treatment outcomes of HIV-infected patients in whom pharmacogenetic testing was performed.Methods: This study involves a retrospective collection of medical records of HIV-infected patients who attended Ramathibodi Hospital during January 2011 to November 2014 and in whom pharmacogenetic testing was performed. We reviewed patients' characteristics, reasons for pharmacogenomic testing, results of human leukocyte antigen-B* (HLA-B*) 5701, HLA-B*3505, HLA-B*4001, CYP2B6, and antiretroviral drug (ARV) levels, treatment planning after the physicians were informed the results, and outcome after changing the treatment.Results: A total of 103 HIV-infected patients with a median age of 46 (range, 20–85) years were enrolled, and 68.9% of them were male. The reasons for pharmacogenomic testing were having adverse drug reactions besides rash (37.9%), screening before prescribing ARV (36.9%), choice of next ARV (19.4%), and confirmation of the cause of skin rash (5.8%). After the physicians knew the results, they adjusted the treatment plan including changing the regimens, changing the ARV dose for avoiding toxicity, and stopping ARV. Among 45 patients, side effects, such as dizziness from efavirenz or rash from abacavir, were improved in 96.4%. Among 27 patients, abnormal laboratory results, such as renal insufficiency from tenofovir or anemia from zidovudine, were improved and some returned to normal in 59.3%. HIV RNA was undetectable after treatment adjustment in 94.9%.Conclusion: The benefits of pharmacogenetic testing are either guiding the initial drug regimen or individualizing regimen, increasing efficacy, and simultaneously avoiding adverse drug reactions. Use of pharmacogenetic testing in HIV-infected Thai adults should be considered.Keywords: adverse drug reaction, antiretroviral drugs, clinical practice, HIV, pharmacogenetics, Thailand

Pansachee Damronglerd,1 Chonlaphat Sukasem,2,4 Wilawan Thipmontree,3 Apichaya Puangpetch,2,4 Sasisopin Kiertiburanakul1 1Deparment of Medicine, 2Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, 3Department of Medicine, Faculty of Medicine, Maharat Nakhon Ratchasima Hospital, Nakhon Ratchasima, 4Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand Objective: We aimed at comparing clinical/immunological outcomes in human immunodeficiency virus (HIV)-infected patients who were treated with CYP2B6-guided and conventional efavirenz (EFV) therapy. Methods: This study was a 24-week prospective randomized controlled trial. Eligible patients were HIV-infected adults yet to start antiretroviral therapy. Twenty-four HIV-infected patients were recruited and randomly assigned to genotype CYP2B6 polymorphism before ART initial dose. Patients with CYP2B6 *6/*6 received 400 mg EFV-based regimen and those with other genotypes received 600 mg EFV-based therapy. Results: For CYP2B6 polymorphism, 12 patients were extensive metabolizers, ten patients were intermediate metabolizers, and only two patients were poor metabolizers (*6/*6). The overall mean EFV plasma concentrations were similar in both groups. The mean drug concentrations (standard deviation) were 1.675 (0.963), 1.445 (0.778), and 1.899 (0.808) µg/mL at week 4, 12, and 24, respectively. The CYP2B6 *6/*6 patient who received low dose of EFV had lower mean EFV level than those who received a normal dose, 1.916 versus 3.915 µg/mL (P

Satariya Trakulsrichai,1,2 Korbtham Sathirakul,3,4 Saranya Auparakkitanon,5 Jatupon Krongvorakul,5 Jetjamnong Sueajai,5 Nantida Noumjad,5 Chonlaphat Sukasem,5 Winai Wananukul2,6 1Department of Emergency Medicine, Faculty of Medicine Ramathibodi Hospital, 2Ramathibodi Poison Center, Faculty of Medicine Ramathibodi Hospital, 3Department of Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand; 4Center for Drug Research Discovery and Development, Thammasat Univerisity, Prathumthani, Thailand; 5Department of Pathology, Faculty of Medicine Ramathibodi Hospital, 6Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand Background: Kratom, known botanically as Mitragyna speciosa (Korth.), is an indigenous tree in Southeast Asia. Kratom is currently easily available worldwide via special shops and the Internet to use as a drug of abuse, opioid alternative, or pain killer. So far, the pharmacokinetics of this plant has been studied only in animals, and there is no such study in humans. The major abundant active alkaloid in Kratom, mitragynine, is one of the promising new chemical substances to be developed as a new drug. The aim of this study was to examine the pharmacokinetics of mitragynine and assess the linearity in pharmacokinetics in chronic users.Methods: Since Kratom is illegal in Thailand, studies in healthy subjects would be unethical. We therefore conducted a prospective study by enrolling ten chronic, regular, healthy users. We adjusted the steady state in each subject by giving a known amount of Kratom tea for 7 days before commencement of the experiment. We admitted and gave different oral doses to subjects to confirm linearity in pharmacokinetics. The mitragynine blood concentrations at 17 times points and the urine concentrations during the 24-hour period were collected and measured by liquid chromatography-tandem mass spectrometry method. Results: Ten male subjects completed the study without adverse reactions. The median duration of abuse was 1.75 years. We analyzed one subject separately due to the abnormal behavior of blood concentration. From data of nine subjects, the pharmacokinetic parameters established were time to reach the maximum plasma concentration (0.83±0.35 hour), terminal half-life (23.24±16.07 hours), and the apparent volume of distribution (38.04±24.32 L/kg). The urine excretion of unchanged form was 0.14%. The pharmacokinetics were observed to be oral two-compartment model. Conclusion: This was the first pharmacokinetic study in humans, which demonstrated linearity and was consistent with the oral two-compartment model with a terminal half-life of about 1 day. The pharmacokinetic linearity and parameters reported are necessary pharmacological information of Kratom, and there is a possibility for it to be developed medically as a pain killer or better opioid substitute in the future. Keywords: kratom, human, pharmacokinetics

Yaowaluck Hongkaew,1,2 Nattawat Ngamsamut,3 Apichaya Puangpetch,1,2 Natchaya Vanwong,1,2 Pornpen Srisawasdi,4 Montri Chamnanphon,1,2 Bhunnada Chamkrachchangpada,3 Teerarat Tan-kam,3 Penkhae Limsila,3 Chonlaphat Sukasem1,2 1Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine, 2Laboratory for Pharmacogenomics, Somdech Phra Debaratana Medical Center (SDMC), Ramathibodi Hospital, Mahidol University, 3Yuwaprasart Waithayopathum Child and Adolescent Psychiatric Hospital, Department of Mental Health Services, Ministry of Public Health, 4Division of Clinical Chemistry, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand Abstract: Hyperprolactinemia is a common adverse effect observed in children with autism spectrum disorder (ASD) during pharmacotherapy with risperidone. The main aim of this study was to investigate important clinical factors influencing the prolactin response in risperidone-treated Thai ASD. A total of 147 children and adolescents (127 males and 20 females) aged 3–19 years with ASD received risperidone treatment (0.10–6.00 mg/day) for up to 158 weeks. Prolactin levels were measured by chemiluminescence immunoassay. The clinical data of patients collected from medical records – age, weight, height, body mass index, dose of risperidone, duration of treatment, and drug-use pattern – were recorded. Hyperprolactinemia was observed in 66 of 147 (44.90%) subjects. Median prolactin level at the high doses (24.00, interquartile range [IQR] 14.30–29.20) of risperidone was significantly found to be higher than at the recommended (16.20, IQR 10.65–22.30) and low (11.70, IQR 7.51–16.50) doses of risperidone. There was no relationship between prolactin levels and duration of risperidone treatment. Dose-dependence is identified as a main factor associated with hyperprolactinemia in Thai children and adolescents with ASD treated with risperidone. This study suggests that risperidone treatment causes prolactin elevations and the effects of risperidone on prolactin are probably dose-related in pediatric patients. Keywords: prolactin level, risperidone, autism spectrum disorders, Thai, hyperprolactinemia

Insee Sensorn,1 Ekaphop Sirachainan,2 Montri Chamnanphon,3 Ekawat Pasomsub,4 Narumol Trachu,5 Porntip Supavilai,1 Chonlaphat Sukasem,3 Darawan Pinthong11Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand; 2Division of Medical Oncology, Department of Medicine, 3Division for Pharmacogenomics and Personalized Medicine, 4Division for Virology, Department of Pathology, 5Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, ThailandBackground: Pharmacogenetic study of cytochrome P450 (CYP) gene CYP2D6 and tamoxifen outcomes remain controversial. Apart from CYP2D6, other drug-metabolizing enzymes and transporters also play a role in tamoxifen metabolic pathways. The aim of this study is to investigate the impact of CYP3A4/5, ABCB1, and ABCC2 polymorphisms on the risk of recurrence in Thai patients who received tamoxifen adjuvant therapy.Methods: Patients with early-stage breast cancer who received tamoxifen adjuvant therapy were recruited in this study. All six single-nucleotide polymorphisms (SNPs), including CYP3A4*1B (-392 A>G)/*18(878 T>C), CYP3A5*3(6986 G>A), ABCB1 3435 C>T, ABCC2*1C (-24 C>T), and ABCC2 68231 A>G, were genotyped using real-time polymerase chain reaction assays. The impacts of genetic variants on disease-free survival (DFS) were analyzed using the Kaplan–Meier method and Cox regression analysis.Results: The ABCB1 3435 C>T was found to have the highest allele frequency among other variants; however, CYP3A4*1B/*18 could not be found in this study. Patients with heterozygous ABCB1 3435 CT genotype showed significantly shorter DFS than those with homozygous 3435 CC genotype (P = 0.041). In contrast, patients who carried homozygous 3435 TT genotype showed no difference in DFS from wild-type 3435 CC patients. Cox regression analysis showed that the relative risk of recurrence was increased by five times (P = 0.043; hazard ratio = 5.11; 95% confidence interval: 1.05–24.74) in those patients carrying ABCB1 3435 CT genotype compared to those with ABCB1 3435 CC.Conclusion: ABCB1 3435 C>T is likely to have a clinically significant impact on recurrence risk in Thai patients with breast cancer who receive tamoxifen adjuvant therapy.Keywords: breast cancer, CYP3A4/5, drug transporters, pharmacogenetics, disease-free survival, tamoxifen

Chonlaphat Sukasem,1 Ramaimon Tunthong,2 Montri Chamnanphon,1 Siwalee Santon,1 Thawinee Jantararoungtong,1 Napatrupron Koomdee,1 Santirhat Prommas,1 Apichaya Puangpetch,1 Prin Vathesatogkit21Division of Pharmacogenetics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 2Division of Cardiology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, ThailandAbstract: Genetic variation in the cytochrome P450 2C19 (CYP2C19) gene has been documented gradually as the determinant conversion and variability in the antiplatelet effect of clopidogrel. The aims of this study were to determine the prevalence of clinically relevant allele variants (CYP2C19*2, CYP2C19*3, and CYP2C19*17) in a Thai study population, and finally determine whether the allele distributes and predicts metabolic phenotypes in clopidogrel treated patients. A total of 1,051 Thai patients participated in this study. Genotypes for CYP2C19 polymorphisms were detected by the microarray-based technique. Furthermore, results of genotyping and platelet aggregation in 96 cardiovascular disease patients on 75 mg clopidogrel maintenance daily dose therapy also were analyzed. Among 1,051 samples, the allele frequencies of CYP2C19 *1/*1, *1/*2, *1/*3, *2/*2, *2/*3, and *1/*17 were found in 428 (40.72%), 369 (35.10%), 72 (6.85%), 77 (7.32%), 59 (5.61%), and 45 (4.30%) of the patients, respectively. Homozygous CYP2C19 *3/*3 was found in one patient (0.10%). Therefore, 40.72% of the patients were predicted as extensive metabolizers, 41.95% as intermediate metabolizers, 13.03% as poor metabolizers, and 4.30% as ultra-rapid metabolizers. Among 96 patients, the frequency of poor metabolizers was significantly higher in the clopidogrel non-responder group than in the responder group (36.0% and 15.5%, respectively, P = 0.03). CYP2C19*1/*17 was observed in responders (n = 2; 2.8%). As a result, CYP2C19 variants were associated with clopidogrel non-responders. However, there is a need for further elucidation of the clinical importance and use of this finding to make firm and cost-effective recommendations for drug treatment in the future.Keywords: CYP2C19 polymorphisms, Thai population, clopidogrel, responders, non-responders

Montri Chamnanphon,1 Khunthong Pechatanan,2 Ekapob Sirachainan,3 Narumol Trachu,4 Wasun Chantratita,5 Ekawat Pasomsub,5 Wilai Noonpakdee,6 Insee Sensorn,1,7 Chonlaphat Sukasem11Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 2Department of Medicine, Phramongkutklao College of Medicine, 3Division of Medical Oncology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 4Research Center, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 5Division of Virology, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 6Department of Biochemistry, Faculty of Science, Mahidol University, 7Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, ThailandPurpose: To investigate the impact of CYP2D6 and CYP2C19 polymorphisms in predicting tamoxifen efficacy and clinical outcomes in Thai breast cancer patients.Methods: Polymorphisms of CYP2D6 and CYP2C19 were genotyped by the AmpliChip™ CYP450 Test (Roche Molecular Diagnostics, Branchburg, NJ, USA) for 57 patients, who were matched as recurrent versus nonrecurrent breast cancers (n = 33 versus n = 24, respectively, with a 5-year follow-up).Results: Based on the genotype data, five CYP2D6 predicted phenotype groups were identified in this study including homozygous extensive metabolizer (13 of 57, 22.80%), extensive/intermediate metabolizer (23 of 57, 40.40%), extensive/poor metabolizer (3 of 57, 5.30%), homozygous intermediate metabolizer (14 of 57, 24.50%), and intermediate/poor metabolizer (4 of 57, 7.00%), and three CYP2C19 genotype groups including homozygous extensive metabolizer (27 of 57, 47.40%), extensive/intermediate metabolizer (27 of 57, 47.40%), and homozygous poor metabolizer (3 of 57, 5.30%). The CYP2D6 variant alleles were *10 (52 of 114, 45.60%), *5 (5 of 114, 4.40%), *41 (2 of 114, 1.80%), *4 (1 of 114, 0.90%), and *36 (1 of 114, 0.90%); the CYP2C19 variant alleles were *2 (27 of 114, 23.70%) and *3 (6 of 114, 5.30%). Kaplan–Meier estimates showed significantly shorter disease-free survival in patients with homozygous TT when compared to those with heterozygous CT or homozygous CC at nucleotides 100C>T and 1039C>T (CYP2D6*10) post-menopausal (log-rank test; P = 0.046). They also had increased risk of recurrence, but no statistically significant association was observed (hazard ratio 3.48; 95% confidence interval 0.86–14.07; P = 0.080).Conclusion: The CYP2D6 and CYP2C19 polymorphisms were not involved in tamoxifen efficacy. However, in the subgroup of post-menopausal women, the polymorphisms in CYP2D6 and CYP2C19 might be useful in predicting tamoxifen efficacy and clinical outcomes in breast cancer patients receiving adjuvant tamoxifen treatment. As the number of breast cancer patients was relatively small in this study, results should be confirmed in a larger group of prospective patients.Keywords: CYP2D6, CYP2C19, disease-free survival, tamoxifen, pharmacogenetics, breast cancer

Teerarat Tan-kam,1 Chutamanee Suthisisang,2 Chosita Pavasuthipaisit,1 Penkhae Limsila,1 Apichaya Puangpetch,3 Chonlaphat Sukasem31Yuwaprasart Waithayopathum Child and Adolescent Psychiatric Hospital, Department of Mental Health Services, Ministry of Public Health, 2Department of Pharmacology, Faculty of Pharmacy, Mahidol University, 3Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, ThailandAbstract: This case report highlights the importance of pharmacogenetic testing in the treatment of attention deficit hyperactive disorder (ADHD). A 6-year-old boy diagnosed with ADHD was prescribed methylphenidate 5 mg twice daily (7 am and noon) and the family was compliant with administration of this medication. On the first day of treatment, the patient had an adverse reaction, becoming disobedient, more mischievous, erratic, resistant to discipline, would not go to sleep until midnight, and had a poor appetite. The All-In-One PGX (All-In-One Pharmacogenetics for Antipsychotics test for CYP2D6, CYP2C19, and CYP2C9) was performed using microarray-based and real-time polymerase chain reaction techniques. The genotype of our patient was identified to be CYP2D6*2/*10, with isoforms of the enzyme consistent with a predicted cytochrome P450 2D6 intermediate metabolizer phenotype. Consequently, the physician adjusted the methylphenidate dose to 2.5 mg once daily in the morning. At this dosage, the patient had a good response without any further adverse reactions. Pharmacogenetic testing should be included in the management plan for ADHD. In this case, cooperation between the medical team and the patients' relatives was key to successful treatment.Keywords: attention deficit hyperactive disorder, pharmacogenomics, CYP2D6, adverse drug reactions, dose adjustment, intermediate metabolizer

Ekaphop Sirachainan,1 Sureerat Jaruhathai,1 Narumol Trachu,2 Ravat Panvichian,1 Thitiya Sirisinha,1 Touch Ativitavas,1 Vorachai Ratanatharathorn,1 Montri Chamnanphon,3 Chonlaphat Sukasem31Division of Medical Oncology, Department of Medicine, 2Research Center, Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand, 3Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, ThailandAim: We evaluated single nucleotide polymorphisms (SNPs) of CYP2D6 to identify those that influence the efficiency of tamoxifen in adjuvant treatment of breast cancer through a matched case–control study.Methods: Peripheral blood DNA was collected from 20 patients with disease recurrence during adjuvant tamoxifen treatment and from 19 patients who had completed 5 years of tamoxifen therapy without recurrence of breast cancer. CYP2D6*4 (1846G > A; rs3892097), CYP2D6*10 (100C > T, rs1065852), and CYP2D6*5 (deletion) were genotyped. The correlation between disease-free survival (DFS) and genotype and clinical outcome were assessed using Kaplan–Meier analysis and a log-rank test.Results: We found the allelic frequency of CYP2D6*10 during this study. Patients with the CYP2D6*10 homozygous variant T/T genotype had a significantly shorter median of DFS than those with C/T (P = 0.036), but DFS was not significantly different from that of patients with the C/C genotype (P = 0.316). One patient who was a carrier both of CYP2D6 G/A (1846G > A) and T/T (100C > T) had DFS of 22.7 months.Conclusions: This study demonstrated that CYP2D6*10/*10 was significantly associated with shorter DFS in Thai breast cancer patients receiving tamoxifen. This was a pilot study investigating the correlation of CYP2D6 polymorphisms and their influence on clinical outcomes in Thai estrogen receptor-positive breast cancer patients.Keywords: breast cancer, CYP2D6 polymorphism, pharmacogenetics, single-nucleotide polymorphism (SNP), tamoxifen

Abstract: Background: The lymphocyte transformation test (LTT) is a standard laboratory method to identify culprit drugs in patients with a history of drug‐induced non‐immediate hypersensitivity and is mainly performed during the recovery phase. The measurement of drug‐specific interferon γ (IFN‐γ)‐releasing cells has been introduced to confirm culprit drugs, even during the acute phase of drug allergy. Objectives: This study aimed to evaluate the capability of the enzyme‐linked immunospot assay (ELISpot) to detect drug‐specific IFN‐γ‐releasing cells during the acute phase and the capability of LTT to identify culprit drugs during the recovery phase in patients presenting with severe cutaneous adverse reactions (SCARs). Methods: Peripheral blood mononuclear cells (PBMCs) from 23 SCAR patients were collected during the acute and recovery phases and assayed for drug‐specific IFN‐γ‐releasing cells and lymphocyte proliferation, respectively. Results: Drug‐specific IFN‐γ‐releasing cells were detectable in 73.9% of SCAR subjects (55.6% and 85.7% in patients who were and were not taking systemic steroids, respectively), whereas LTT results were positive in 52.2% of SCAR subjects. The frequencies of drug‐specific IFN‐γ‐releasing cells were significantly higher in patients with positive LTT than in those with negative LTT (260.1 ± 110.0 and 46.6 ± 20.7 cells/106 PBMCs, P = 0.01). A significant correlation between the results of the IFN‐γ ELISpot assay and LTT was demonstrated (r = 0.65, P value <0.01). Conclusion: The IFN‐γ ELISpot assay could be a useful tool to identify culprit drugs in SCAR patients when culprit drug identification is urgently needed during the acute phase of drug allergy. [ABSTRACT FROM AUTHOR]

This study explores genomic alterations in cholangiocarcinoma (CCC) tissues in Thai patients. We identified and reviewed the records of patients who had been diagnosed with CCC and for whom sufficient tumor samples for DNA and RNA extraction were available in our database. The specimens were explored for EGFR, KRAS, BRAF, and PIK3CA mutations and ROS1 translocation in 81 samples. Immunohistochemistry staining for HER2, ALK, and Ki-67 expression was tested in 74 samples. Prevalence of EGFR, KRAS, and PIK3CA mutations in this study was 21%, 12%, and 16%, respectively. No BRAF V600 mutation or ROS1 translocation was found. Patients with T790M mutation had a significantly longer overall survival (18.84 months) than those with the other types of EGFR mutations (4.08 months; hazard ratio [HR]: 0.26, P=0.038) and also had a significantly lower median Ki-67 (22.5% vs 80%, P=0.025). Furthermore, patients with PIK3CA mutations had a significantly longer median progression-free survival (15.87 vs 7.01 months; HR: 0.46, P=0.043). Strongly positive HER2 expression was found in only 1 patient, whereas ALK expression was not found. The presence of EGFR and/or PIK3CA mutations implies that targeted drugs may provide a feasible CCC treatment in the future. [ABSTRACT FROM AUTHOR]

Background Allopurinol is a frequent cause of severe cutaneous adverse reactions ( SCARs), such as drug reaction with eosinophilia and systemic symptoms ( DRESS), Stevens-Johnson syndrome ( SJS) and toxic epidermal necrolysis ( TEN). The reactions can potentially be fatal. As drug rechallenge in patients with a history of drug-induced SCARs is contraindicated, in vitro testing may have a diagnostic role as a confirmation test. Objectives To study the diagnostic value of interferon ( IFN)-γ enzyme-linked immunospot ( ELISpot) assay as a confirmatory test in patients with a history of allopurinol-induced SCARs. Methods Peripheral blood mononuclear cells ( PBMCs) from 24 patients with a history of allopurinol-induced SCAR (13 DRESS, 11 SJS/ TEN) and 21 control subjects were incubated with allopurinol or oxypurinol in the presence or absence of antiprogrammed death ligand 1 antibody (anti- PD-L1). The numbers of IFN-γ-releasing cells after stimulation in each group were subsequently measured with ELISpot. Results The numbers of IFN-γ-releasing cells in allopurinol-allergic subjects were significantly higher than in control subjects when stimulating PBMCs with oxypurinol 100 μg mL−1, especially when adding anti- PD-L1 supplementation. According to the receiver operating characteristic curve results, the optimal discriminatory power of IFN-γ ELISpot in confirming diagnosis of allopurinol-induced SCARs can be obtained using 16 spot-forming cells per 106 PBMCs as a cut-off value upon oxypurinol/anti- PD-L1 stimulation (79·2% sensitivity and 95·2% specificity). Conclusions The measurement of oxypurinol/anti- PD-L1-inducing IFN-γ-releasing cells yields a high diagnostic value in distinguishing between allopurinol-allergic and control subjects. This technique is beneficial in confirming diagnosis of allopurinol-induced SCARs in patients whose reaction develops while taking multiple drugs. [ABSTRACT FROM AUTHOR]