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Aim. The purpose of this work is to emphasize the importance and practical benefits of pharmacogenetics in medicine, demonstrating how the integration of pharmacogenetics into clinical practice can improve treatment outcomes and enhance the safety of therapies. Pharmacogenetics is a rapidly developing branch of pharmacology that studies how genetic variation affects an individual’s response to drugs. By understanding these genetic differences, healthcare providers can tailor drug therapy to maximize efficacy and minimize adverse drug reactions. The field aims to move away from the traditional one-size-fits-all approach and instead personalize medical treatment based on a person’s genetic makeup. The ability to predict a person’s response to medication based on their genetic profile has profound implications. For example, pharmacogenetic testing can identify patients at risk for life-threatening adverse drug reactions, such as drug-induced liver injury. This proactive approach can prevent adverse events, improving patient safety and the overall quality of care. In addition, pharmacogenetics aids in the development of new drugs by identifying genetic markers associated with drug responses, optimizing the drug development process, and reducing the time and costs associated with bringing new drugs to market. Key advances in pharmacogenetics include the identification of genetic polymorphisms in enzymes, such as cytochrome P450, that affect drug metabolism, thereby influencing both safety and efficacy. Pharmacogenetic testing allows doctors to predict the best drug and dosage for a patient, improving treatment outcomes and reducing the risk of adverse drug events. Despite its potential, the integration of pharmacogenetics into clinical practice faces challenges, including a lack of reliable clinical evidence, inadequate physician education, and the need for a comprehensive health IT infrastructure to support the use of genetic data. Ethical and legal issues, such as patient privacy and the risk of genetic discrimination, also present significant obstacles. However, continued research, the development of genetic testing technologies, and interdisciplinary collaborations are paving the way for more widespread adoption of pharmacogenetics, which promises to significantly improve patient care and healthcare efficiency. Key resources such as PharmGKB, CPIC, and the NIH provide valuable information and guidance for clinicians, researchers, and students, helping bridge the gap between genetics research and clinical application. Conclusions. Pharmacogenetics represents a significant advancement in personalized medicine, offering the potential to tailor drug therapies to individual genetic profiles. Although the field has made substantial progress, challenges remain in the form of insufficient clinical evidence, implementation barriers, and ethical concerns. Continued research and collaboration among stakeholders are essential to fully realize the benefits of pharmacogenetic testing in clinical practice.

Abstract Background In clinical practice, family medication history is not routinely assessed as part of a patient’s family health history (FHH). The information is self-reported and can depend on the individual’s subjective perception. To illustrate how pharmacogenetic (PGx) testing results could be used to validate self-reported family medication history on drug-related problems (DRP), as well as to inform medication-related decisions, we herein present a case involving ten members of the same family. Case Presentation Prior to a planned surgery, a preemptive PGx panel test was performed for a nine-year-old girl due to self-reported family medication history. The PGx panel test was also performed for her three siblings, parents, and grandparents. The focus was directed to the paternal grandmother, as she reported DRP from the hypnotic agent propofol, and to the maternal grandmother, as she described DRP after the administration of codeine and tramadol. A commercial PGx panel test of 100 variations in 30 different genes was conducted and analyzed focusing on genetic variants in cytochrome P450 enzyme 2B6 (CYP2B6), and CYP2D6 as they are involved in the biotransformation of propofol and the bioactivation of codeine and tramadol, respectively. The girl was identified as (1) CYP2B6 intermediate metabolizer (IM) with reduced enzyme activity and (2) CYP2D6 poor metabolizer (PM) with no enzyme activity. Regarding the planned surgery, it was recommended (1) to carefully titrate propofol dosage with increased monitoring of potential DRP and (2) to avoid opioids whose activation is mediated by CYP2D6 (e.g. codeine and tramadol). Further PGx testing revealed (1) the paternal grandmother as CYP2B6 normal metabolizer (NM) and (2) the maternal grandmother as CYP2D6 NM. Conclusion The original trigger for PGx testing was the self-reported, conspicuous family medication history of DRP reported by the grandmothers. However, the girl’s genotype predicted phenotypes of CYP2B6 IM and CYP2D6 PM, differed from the grandmothers’. With this exemplary case, we propose that hereditary concerns based on self-reported information on DRP should be verified by a PGx panel test, when the respective drug exhibits a PGx association. Also, the girl’s PGx testing results provided important medication recommendations, which were considered perioperatively by the anesthetist suggesting to use PGx testing results preemptively to inform medication-related decisions.

Methotrexate (MTX) is an anti-folate chemotherapeutic agent that is considered to be a gold standard in Acute Lymphoblastic Leukemia (ALL) therapy. Nevertheless, toxicities induced mainly due to high doses of MTX are still a challenge for clinical practice. MTX pharmacogenetics implicate various genes as predictors of MTX toxicity, especially those that participate in MTX intake like solute carrier family 19 member 1 (SLC19A1). The aim of the present study was to evaluate the association between SLC19A1 polymorphisms and its regulatory miRNAs with MTX toxicity in children with ALL. A total of 86 children with ALL were included in this study and were all genotyped for rs2838958, rs1051266 and rs1131596 SLC19A1 polymorphisms as well as the rs56292801 polymorphism of miR-5189. Patients were followed up (48, 72 and 96 h) after treatment with MTX in order to evaluate the presence of MTX-associated adverse events. Our results indicate that there is a statistically significant correlation between the rs1131596 SLC19A1 polymorphism and the development of MTX-induced hepatotoxicity (p = 0.03), but there is no significant association between any of the studied polymorphisms and mucositis or other side effects, such as nausea, emesis, diarrhea, neutropenia, skin rash and infections. In addition, when genotype TT of rs1131596 and genotype AA of rs56292801 are both present in a patient then there is a higher risk of developing severe hepatotoxicity (p = 0.0104).

Yudisia Ausi,1,2 Melisa Intan Barliana,2,3 Maarten J Postma,3,4 Auliya A Suwantika3,5 1Doctor Program in Pharmacy, Faculty of Pharmacy, Universitas Padjadjaran, Jatinangor, Indonesia; 2Department of Biological Pharmacy, Faculty of Pharmacy, Universitas Padjadjaran, Jatinangor, Indonesia; 3Center of Excellence for Pharmaceutical Care Innovation, Universitas Padjadjaran, Bandung, Indonesia; 4Department of Health Sciences, University Medical Center Groningen, University of Groningen, Groningen, Netherlands; 5Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Universitas Padjadjaran, Jatinangor, IndonesiaCorrespondence: Auliya A Suwantika, Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Universitas Padjadjaran, Jalan Raya Bandung Sumedang KM 21 Jatinangor, Sumedang, 45363, Indonesia, Tel +62 22 84288828, Email auliya@unpad.ac.idAbstract: Pharmacogenetics is a promising approach in future personalized medicine. This field holds excellent prospects for healthcare quality acceleration. It promotes the transition to the precision medicine era, whereby a health treatment is driven by a deeper understanding of individual characteristics by interpreting the underlying genomic variation. Pharmacogenetics has been developing rapidly since the human genome project. Many pharmacogenetics studies have shown the association between genetic variants and therapy outcomes. Several pharmacogenetics working groups have recommended guidelines for the clinical application of pharmacogenetics. However, the development of pharmacogenetics in low- and middle-income countries (LMICs) is still retarded behind. The problems mainly include clinical evidence, technology, policy and regulation, and human resources. Currently, available genome and drug effect data in LMICs are scarce. Pharmacogenetics development should be escalated with evidence proof through research collaboration across countries. The challenges of pharmacogenetics implementation are discussed comprehensively in this article, along with the prospect of pharmacogenetics-guided personalized medicine in developed countries. Stepwise is expected to help the researchers and stakeholders define the problem that hindered the pharmacogenetics application.Keywords: pharmacogenetics, implementation, LMICs, personalized medicine

Abstract Background There is no doubt that genetic factors have the potential to predict the therapeutic outcomes of antidepressants in patients with major depressive disorder (MDD). This study investigated the association between genetic variants involved in serotonin signaling and brain-derived neurotrophic factor (BDNF) with the response to escitalopram treatment in patients with MDD. We focused on examining the influence of 5-HTTLPR (ins/del), HTR2A rs9316233, BDNF rs962369, CYP2C19 and CYP2D6 on the clinical response to escitalopram. Methods The patients were recruited from outpatient psychiatric clinics in Košice between 2020 and 2022. Patients received escitalopram for 12 weeks at a fixed dose of 10 mg daily. Clinical assessment was done at baseline and after 4, 8, and 12 weeks using the 21-item Hamilton Depression Rating Scale (HAMD-21). Results At the end of week 12, 57 (65%) patients were defined as responders to escitalopram treatment, while 31 (35%) patients were non-responders. Genotyping revealed that carriers of the short allele (S) of 5-HTTLPR exhibit a significantly lower therapeutic response to escitalopram measured by HAMD-21 than the long allele (L) carriers (p = 0.01). Adjusting for CYP2C19 and CYP2D6 metabolizer genotypes did not modify the observed relationship between 5-HTTLPR and treatment response. No significant associations were found for HTR2A rs9316233 or BDNF rs962369 variants and the treatment response. Conclusions These findings underscore the utility of 5-HTTLPR genotyping in guiding escitalopram therapy for MDD patients. Further research with larger cohorts is warranted to validate these results and elucidate additional genetic determinants of antidepressant efficacy.

Abstract While significant strides have been made in understanding pharmacogenetics (PGx) and gene-drug interactions, there remains limited characterization of population-level PGx variation. This study aims to comprehensively profile global star alleles (haplotype patterns) and phenotype frequencies in 58 pharmacogenes associated with drug absorption, distribution, metabolism, and excretion. PyPGx, a star-allele calling tool, was employed to identify star alleles within high-coverage whole genome sequencing (WGS) data from the 1000 Genomes Project (N = 2504; 26 global populations). This process involved detecting structural variants (SVs), such as gene deletions, duplications, hybrids, as well as single nucleotide variants and insertion-deletion variants. The majority of our PyPGx calls for star alleles and phenotype frequencies aligned with the Pharmacogenomics Knowledge Base, although notable population-specific frequencies differed at least twofold. Validation efforts confirmed known SVs while uncovering several novel SVs currently undefined as star alleles. Additionally, we identified 210 small nucleotide variants associated with severe functional consequences that are not defined as star alleles. The study serves as a valuable resource, providing updated population-level star allele and phenotype frequencies while incorporating SVs. It also highlights the burgeoning potential of cost-effective WGS for PGx genotyping, offering invaluable insights to improve tailored drug therapies across diverse populations.

Metabolic syndrome (MetS) presents a significant global health challenge, characterized by a cluster of metabolic alterations including obesity, hypertension, insulin resistance/dysglycemia, and atherogenic dyslipidemia. Advances in understanding and pharmacotherapy have added complexity to MetS management, particularly concerning drug interactions and pharmacogenetic variations. Limited literature exists on drug–drug–gene interactions (DDGIs) and drug–drug–transporter gene interactions (DDTGIs), which can significantly impact pharmacokinetics and pharmacodynamics, affecting treatment outcomes. This narrative review aims to address the following three key objectives: firstly, shedding a light on the PK metabolism, transport, and the pharmacogenetics (PGx) of medicines most commonly used in the MetS setting (relevant lipid-lowering drugs, antihypertensives and antihyperglycemics agents); secondly, exemplifying potential clinically relevant pharmacokinetic drug interactions, including drug–drug interactions, DDGIs, and DDTGIs; and, thirdly, describing and discussing their potential roles in clinical practice. This narrative review includes relevant information found with the use of interaction checkers, pharmacogenetic databases, clinical pharmacogenetic practice guidelines, and literature sources, guided by evidence-based medicine principles.

Genetic factors influence medication response (pharmacogenetics), affecting the pharmacodynamics and pharmacokinetics of many medicaments used in clinical care. The ability of medications to cross the blood–brain barrier (BBB) represents a critical putative factor in the effectiveness and tolerability of various medications relevant to central nervous system disorders (CNS), cancer, and broader medical conditions at a pharmacokinetic (dosing) level. Pharmacogenetics has the potential to personalise medicine to a greater extent than has been possible, with the potential to help reduce heuristic delays to effective tolerable pharmacotherapy. Here, we critically examine and summarise the evidence, particularly for ABCB1 polymorphisms associated with drug transportation and other clinical relevance. These transporters appear to have a role in BBB pharmacogenetics and may indicate new avenues of research that extend beyond the current paradigm of CYP450 polymorphisms. We identify some of the most promising variants for clinical translation while spotlighting the complexities of the involved systems and limitations of the current empirical literature.

Globally, cardio vascular diseases (CVD) remain the primary cause of morbidity and mortality. Pharmacogenomics (PGxs) has profoundly changed how various drug classes are managed in CVDs. For example, genetic polymorphisms in genes such as SLCO1B1 impact how a person responds to statins such as rosuvastatin and atorvastatin, where as the interindividual variability in the reaction to statins (Fluvastatin)used in lipid-lowering therapy can be partly explained by genetic variations in genes encoding drug-metabolizing enzymes such cytochrome P450 and transporters like OATP1B1. Similarly, in antiplatelet therapy, polymorphisms in CYP2C19 affect clopidogrel metabolism, influencing its efficacy in preventing thrombotic events. Genes such as CYP2C9 and VKORC1 are crucial for the metabolism and response to acenocoumarol and warfarin during anticoagulant therapy and monitoring bleeding risk. Genetic variations in CYP2D6 affect the metabolism and effectiveness of propafenone and metoprolol. Understanding the PGx presumptions of these cardiovascular drugs may help develop personalized treatment strategies that lower the possibility of adverse drug reactions, obtain desired therapeutic outcomes, and improve patient compliance and safety with respect to each patient’s unique genetic makeup.

Abstract Background The Alpe-DPD study (NCT02324452) demonstrated that prospective genotyping and dose-individualization using four alleles in DPYD (DPYD*2A/rs3918290, c.1236G > A/rs75017182, c.2846A > T/rs67376798 and c.1679 T > G/rs56038477) can mitigate the risk of severe fluoropyrimidine toxicity. However, this could not prevent all toxicities. The goal of this study was to identify additional genetic variants, both inside and outside DPYD, that may contribute to fluoropyrimidine toxicity. Methods Biospecimens and data from the Alpe-DPD study were used. Exon sequencing was performed to identify risk variants inside DPYD. In silico and in vitro analyses were used to classify DPYD variants. A genome-wide association study (GWAS) with severe fluoropyrimidine-related toxicity was performed to identify variants outside DPYD. Association with severe toxicity was assessed using matched-pair analyses for the exon sequencing and logistic, Cox, and ordinal regression analyses for GWAS. Results Twenty-four non-synonymous, frameshift, and splice site DPYD variants were detected in ten of 986 patients. Seven of these variants (c.1670C > T, c.1913 T > C, c.1925 T > C, c.506delC, c.731A > C, c.1740 + 1G > T, c.763 − 2A > G) were predicted to be deleterious. The carriers of either of these variants showed a trend towards a 2.14-fold (95% CI, 0.41–11.3, P = 0.388) increased risk of severe toxicity compared to matched controls (N = 30). After GWAS of 942 patients, no individual single nucleotide polymorphisms achieved genome-wide significance (P ≤ 5 × 10−8), however, five variants were suggestive of association (P

Abstract Background Human immunodeficiency virus (HIV) and tuberculosis (TB) are major contributors to morbidity and mortality in sub-Saharan Africa including Cameroon. Pharmacogenetic variants could serve as predictors of drug-induced hepatotoxicity (DIH), in patients with TB co-infected with HIV. We evaluated the occurrence of DIH and pharmacogenetic variants in Cameroonian patients. Methods Treatment-naïve patients with HIV, TB or TB/HIV co-infection were recruited at three hospitals in Cameroon, between September 2018 and November 2019. Appropriate treatment was initiated, and patients followed up for 12 weeks to assess DIH. Pharmacogenetic variants were assessed by allele discrimination TaqMan SNP assays. Results Of the 141 treatment naïve patients, the overall incidence of DIH was 38% (53/141). The highest incidence of DIH, 52% (32/61), was observed among HIV patients. Of 32 pharmacogenetic variants, the slow acetylation variants NAT2*5 was associated with a decreased risk of DIH (OR: 0.4; 95%CI: 0.17–0.96; p = 0.038), while NAT2*6 was found to be associated with an increased risk of DIH (OR: 4.2; 95%CI: 1.1–15.2; p = 0.017) among patients treated for TB. Up to 15 SNPs differed in ≥ 5% of allele frequencies among African populations, while 25 SNPs differed in ≥ 5% of the allele frequencies among non-African populations, respectively. Conclusions DIH is an important clinical problem in African patients with TB and HIV. The NAT2*5 and NAT2*6 variants were found to be associated with DIH in the Cameroonian population. Prior screening for the slow acetylation variants NAT2*5 and NAT2*6 may prevent DIH in TB and HIV-coinfected patients.

Asthma is a chronic inflammatory respiratory condition, characterized by variable airflow limitation, leading to clinical symptoms such as dyspnea and chest tightness. These symptoms result from an underlying inflammatory process. The β2 agonists are bronchodilators prescribed for the relief of the disease. Nevertheless, their efficacy exhibits substantial interindividual variability. Currently, there is widespread recognition of the association between specific genetic variants, predominantly located within the ADRB2 and ADCY9 genes and their efficacy. This association, usually represented by the presence of non-synonymous single nucleotide polymorphisms (SNPs) have a strong impact in the protein functionality. The prevalence of these mutations varies based on the ethnic composition of the population and thus understanding the profiles of variability in different populations would contribute significantly to standardizing the use of these medications. In this study, we conducted a sequence-based genotyping of the relevant SNPs within the ADRB2 and ADCY9 genes in patients undergoing treatment with bronchodilators and/or corticosteroids at two healthcare facilities in the state of Rio de Janeiro, Brazil. We investigated the presence of c.46A>G, c.79C>G, c.252G>A, and c.491C>T SNPs within the ADRB2, and c.1320018 A>G within the ADCY9. Our results were in line with existing literature data with both for individuals in Brazil and Latin American.

Abstract Pharmacogenetics investigates sequence of genes that affect drug response, enabling personalized medication. This approach reduces drug-induced adverse reactions and improves clinical effectiveness, making it a crucial consideration for personalized medical care. Numerous guidelines, drawn by global consortia and scientific organizations, codify genotype-driven administration for over 120 active substances. As the scientific community acknowledges the benefits of genotype-tailored therapy over traditionally agnostic drug administration, the push for its implementation into Italian healthcare system is gaining momentum. This evolution is influenced by several factors, including the improved access to patient genotypes, the sequencing costs decrease, the growing of large-scale genetic studies, the rising popularity of direct-to-consumer pharmacogenetic tests, and the continuous improvement of pharmacogenetic guidelines. Since EMA (European Medicines Agency) and AIFA (Italian Medicines Agency) provide genotype information on drug leaflet without clear and explicit clinical indications for gene testing, the regulation of pharmacogenetic testing is a pressing matter in Italy. In this manuscript, we have reviewed how to overcome the obstacles in implementing pharmacogenetic testing in the clinical practice of the Italian healthcare system. Our particular emphasis has been on germline testing, given the absence of well-defined national directives in contrast to somatic pharmacogenetics.

INTRODUCTION. The pathogenesis of antibiotic-associated drug-induced liver injury (DILI) in children has not been fully elucidated to date. Certain genotypes in patients increase the probability of developing DILI. Therefore, the identification of pharmacogenetic markers associated with DILI in children is essential.АIM. This study aimed to identify pharmacogenetic biomarkers of new-onset DILI associated with tigecycline and meropenem in children.MATERIALS AND METHODS. This prospective observational study was conducted in the Morozov Children’s City Clinical Hospital from 1 February 2020 to 1 September 2021. The study analysed the incidence and types of antibiotic-associated adverse drug reactions (ADRs) in 100 critically ill children aged 0 to 17 years (44 boys and 56 girls). Pharmacogenetic testing was performed in children with ADRs (n=30) to identify potential mechanisms involved in the development of their ADRs. The authors isolated and tested DNA from buccal epithelium swabs using the Agena Bioscience iPLEX® PGx Pro-based VeriDose® Core Panel covering 68 single nucleotide polymorphisms (SNPs) or short insertions and deletions (INDELs) and 5 copy number variants (CNVs).RESULTS. The odds of developing DILI associated with meropenem and tigecycline were higher in carriers of the homozygous cytochrome genotype CYP3A5*3/*3 (OR: 12.6; 95% CI: 1.9–79.4, r=6.54, p=0.011) than in patients with the heterozygous genotype CYP3A5*1A/*3. The odds were even higher in patients not carrying the CYP3A5*1A/*3 genotype (OR: 17.14; 95% CI: 1.79–16.3, r=6.24, p=0.013). The detection of the CYP3A5*3/*3 ge­notype had a prognostic accuracy of 76.7%, a sensitivity of 82%, and a specificity of 74% in predicting the risk of DILI associated with meropenem and tigecycline. Moreover, children with DILI carried the heterozygous ge­notype SLCO1B1*1/*5 (rs4149056 polymorphism) more often than children with other adverse reactions ­associated with meropenem and tigecycline (r=9.8, p=0.002).CONCLUSION. The results of this study prove the prognostic significance of the homozygous cytochrome genotype CYP3A*3/*3 as an indicator of a potential risk for developing DILI associated with meropenem and tigecycline in children in critical conditions.The study was registered at ClinicalTrials.gov under No. NCT04141657 on 24 October 2019.

Identification of the genetic features that determine a patient’s individual response to a medicinal product and provision of this information to a doctor helps to predict the effectiveness of therapy and the risk of adverse drug reactions. Dmitry A. Sychev — Academician of the Russian Academy of Sciences, Doctor of Medical Sciences, Full Professor, Rector of the Russian Medical Academy of Continuous Professional Education — talks about the importance of a personalised approach to selecting medicinal products and methods for their efficacy and safety control.

Background: Tacrolimus therapy is standard of care for immunosuppression after lung transplantation. However, tacrolimus exposure variability during the early postoperative period may contribute to poor outcomes in this population. Few studies have examined tacrolimus pharmacokinetics (PK) during this high-risk period. Methods: We conducted a retrospective pharmacokinetic study in lung transplant recipients at the University of Pennsylvania who were enrolled in the Lung Transplant Outcomes Group cohort. We used nonlinear mixed-effects regression to derive a population PK model in 270 patients and examined validity in a separate cohort of 114 patients. Covariates were examined with univariate analysis and a multivariable model was developed using forward and backward stepwise selection. The performance of the final model in the validation cohort was examined with calculation of prediction error (PE). Results: We developed a 1-compartment base model with a fixed rate absorption constant. Covariates improving model fit were postoperative day, hematocrit, transplant type, CYP3A5 genotype, weight, and exposure to cytochrome p450 enzyme (CYP) inhibitor drugs. The strongest predictor of tacrolimus clearance was postoperative day, with median predicted clearance increasing more than 3-fold over the 14-day study period. In the validation cohort, the final model showed a mean PE of 36.4% (95% confidence interval 30.8%-41.9%) and a median PE of 7.2% (interquartile range −29.3% to 70.53%). Conclusions: Tacrolimus clearance is highly dynamic during the early postlung transplant period. Population PK models that include lung-transplant–specific covariates may enable precision dosing algorithms that account for this highly dynamic clearance. Future multicenters studies including a broader set of covariates are warranted.

BackgroundAntiseizure medications (ASM) exhibit considerable interindividual variability in terms of efficacy and adverse events. Genetic variation is thought to contribute to these differences in clinical outcomes. Specifically, the response to valproic acid (VPA), a widely used ASM, is influenced by multiple pharmacogenetic factors. However, and in contrast to other ASMs such as phenytoin and carbamazepine, there is a paucity of data on the association between VPA and various gene variants. The aim of this study was hence to evaluate the influence of candidate pharmacogenetic variants on VPA efficacy, toxicity and serum concentrations in a homogeneous cohort of patients newly diagnosed with genetic generalized epilepsies (GGE).MethodsIn this prospective cohort study, demographic, clinical and treatment outcomes of GGE patients were retrieved from their medical records. Whole exome sequencing was performed in collaboration with Epi25. Gene variants associated with VPA efficacy, metabolism and toxicities were retrieved from PharmGKB. An analysis was then conducted to explore potential associations between these gene variants and VPA clinical outcomes.ResultsOf the 166 patients included, 60 (36.1%) experienced treatment failure while 106 (63.9%) achieved treatment success. After adjusting for VPA maintenance dose, carriers of the rs3892097 (CYP2D6) variant were 2.5 times more likely to experience treatment failure compared to wildtype (p = 0.026). The rs1057910 variant (CYP2C9*3) was associated with increased serum VPA concentrations (p = 0.034). Moreover, the rs1137101 variant (LEPR gene, a metabolism regulator) was significantly associated with a higher risk of weight gain (regression coefficient of 3.430 [0.674; 6.186], p = 0.015) and a higher frequency of hair loss (OR = 3.394 [1.157; 9.956], p = 0.026), while the rs4480 variant (SOD2 gene, encoding for a mitochondrial scavenging enzyme) was correlated with a lower frequency of hair loss (OR = 0.276 [0.089; 0.858], p = 0.026).ConclusionThese findings highlight the role of genetic factors in VPA treatment and underscore the potential for developing therapeutic strategies to enhance patient outcomes and minimize adverse effects.

Abstract Background and Aim Among the cardiovascular diseases (CVDs), heart failure, hypertension, and myocardial infarction are associated with the greatest number of disability‐adjusted life years due to lifestyle changes and the failure of therapeutic approaches, especially the one‐size‐fits‐all interventions. As a result, there has been advances in defining genetic variants responsible for different responses to cardiovascular drugs such as antiplatelets, anticoagulants, statins, and beta‐blockers, which has led to their usage in guiding treatment plans. This study comprehensively reviews the current state‐of‐the‐art potential of pharmacogenomics in dramatically altering CVD treatment. It stresses the applicability of pharmacogenomic technology, the threats associated with its adoption in the clinical setting, and proffers relevant solutions. Methods Literature search strategies were used to retrieve articles from various databases: PubMed, Google Scholar, and EBSCOhost. Articles with information relevant to pharmacogenomics, DNA variants, cardiovascular diseases, sequencing techniques, and drug responses were reviewed and analyzed. Results DNA‐based technologies such as next generation sequencing, whole genome sequencing, whole exome sequencing, and targeted segment sequencing can identify variants in the human genome. This has played a substantial role in identifying different genetic variants governing the poor response and adverse effects associated with cardiovascular drugs. Thus, this has reduced patients' number of emergency visits and hospitalization. Conclusion Despite the emergence of pharmacogenomics, its implementation has been threatened by factors including patient compliance and a low adoption rate by clinicians. Education and training programs targeting both healthcare professionals and patients should be established to increase the acceptance and application of the emerging pharmacogenomic technologies in reducing the burden of CVDs.

IntroductionEzetimibe inhibits cholesterol uptake by modulation of intestinal sterol absorption. Currently, although some studies have shown alterations in ezetimibe levels caused by alterations in the ABCG5, ABCG8, NPC1L1 or UGT1A1 genes, there are no pharmacogenetic guidelines to confirm these biomarkers. The aim of this work was to evaluate the effect of 49 variants in 22 pharmacogenes related to metabolism and transport.MethodsA total of 96 healthy volunteers from four bioequivalence clinical trials of ezetimibe as monotherapy or in combination with simvastatin were studied. Blood samples were extracted for unconjugated ezetimibe plasma quantification and genotyping.Results and DiscussionNo association of metabolizing enzyme variants with ezetimibe pharmacokinetic parameters was found. The results show some trends in the univariate analysis for ABCB1 rs2032582 or ABCC2 rs2273697 and Cmax (p univariate (puv) = 0.056 and 0.087, respectively), which finally reach significance in the multivariate analysis (p multivariate (pmv) = 0.049 and 0.048, respectively). Nevertheless, these results need to be validated in future studies.

Objective: This study explores the frequency of human leukocyte antigen (HLA) genes, particularly HLA-B alleles, within the Kuwaiti population. We aim to identify alleles with known associations to adverse drug reactions (ADRs) based on existing literature. We focus on the HLA-B gene due to its well-documented associations with severe cutaneous adverse reactions and the extensive pharmacogenetic research supporting its clinical relevance.MethodsWe utilized the HLA-HD tool to extract, annotate, and analyse HLA-B alleles from the exome data of 561 Kuwaiti individuals, sequenced on the Illumina HiSeq platform. HLA typing was conducted using the HLA-HD tool with a reference panel from the IPD-IMGT/HLA database. The major HLA-B pharmacogenetic markers were obtained from the HLA Adverse Drug Reaction Database, focusing on alleles with significant ADR associations in published literature.ResultsThe distribution of HLA-B alleles in the Kuwaiti population revealed that the most frequent alleles were HLA-B*50:01 (10.52%), HLA-B*51:01 (9.89%), HLA-B*08:01 (6.06%), HLA-B*52:01 (4.55%), HLA-B*18:01 (3.92%), and HLA-B*41:01 (3.65%). Notably, alleles HLA-B*13:01, HLA-B*13:02, HLA-B*15:02, HLA-B*15:13, HLA-B*35:02, HLA-B*35:05, HLA-B*38:01, HLA-B*40:02, HLA-B*44:03, HLA-B*51:01, HLA-B*57:01 and HLA-B*58:01 were identified with known associations to various ADRs. For example, HLA-B*51:01 was associated with clindamycin, phenobarbital, and phenytoin, and was found in 18% of individuals.ConclusionOur study enriches the regional genetic landscape by delineating HLA-B allele variations within Kuwait and across the Arabian Peninsula. This genetic insight, along with the identification of markers previously linked to drug hypersensitivity, provides a foundation for future pharmacogenetic research and potential personalized medicine strategies in the region.

IntroductionInflammatory factors released during severe coronavirus disease-19 (COVID-19) caused by acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are known to influence drug exposure, but data on the effect of mild infection are few. Here we describe for the first time an increase in plasma imatinib and norimatinib concentrations observed in a series of 5 patients treated with imatinib for gastrointestinal stromal tumor (GIST) after mild COVID-19.MethodsThe patients were undergoing routine therapeutic drug monitoring (TDM) and pharmacogenetic (PGx) analyses of polymorphisms in genes involved in imatinib metabolism and transport (CYP3A4, CYP3A5, ABCB1, and ABCG2) when SARS-CoV-2 infection occurred. Imatinib and its active metabolite norimatinib concentrations were determined at Ctrough using a validated LC-MS/MS method. PGx analyses were performed by KASP genotyping assays on a Real-Time PCR system. All patients received imatinib 400 mg/day. Case 1 was prospectively monitored. Cases 2-5 were identified retrospectively.ResultsOn average, imatinib Ctrough increased significantly by 70% during COVID-19, whereas norimatinib showed a 44% increase compared with pre-COVID-19 levels. Elevated plasma imatinib concentrations persisted up to 6 months after infection remission. In 3 cases, this increase reflected the occurrence or worsening of imatinib side effects.ConclusionThis case-series highlights the clinical impact of SARS-CoV-2 infection on the management of patients with GIST treated with imatinib.

IntroductionIn collaboration with the Minnesota Hmong community, we have previously discovered significant differences in allele frequencies for key Single Nucleotide Variations (SNVs) within Very Important Pharmacogenes (VIPs) between Hmong and East Asians. Recognizing the potential clinical implications of these observed differences, we sought to validate these observations in a Hmong cohort residing in California, the state with the largest Hmong population in the US. Robust validation of these differences would affect motivation for clinicians treating individuals who identify as Hmong to consider pharmacogenomic (PGx) testing as a means to improve clinical decision making when using therapeutic agents in this unique population.MethodGuided by California Hmong community leaders and utilizing the basic approach of community-based participatory research, demographic, clinical information and a buccal swab was obtained from Hmong adults residing in California. A commercial PGx testing panel was performed on these samples and specific allele frequencies of interest were compared between California and Minnesota Hmong. Allele frequency differences between California Hmong, East Asians and Europeans, were also compared. Return-of-PGx-results and presentations of group data were made to members of the Hmong along with PGx educational sessions to help interpret the observations.ResultsIn 118 California Hmong who completed the study, the allele frequencies for SNV’s were similar to previous Minnesota Hmong results. Furthermore, out of the 18 SNVs that were not previously reported in Hmong, allele frequencies were statistically different in 38% (7/18) of SNVs comparing California Hmong to East Asians, and in 77.8% (14/18) SNVs comparing California Hmong to Europeans.ConclusionThese results validate the original study’s findings that Hmong people living in different US locations have similar allele frequencies for key PGx genes. Further, for many of these PGx genes, their allele frequencies are significantly different compared to either East Asians or Europeans. Clinicians should consider these important differences when prescribing medications for people who identify as Hmong.

BackgroundIn the context of the cytokine storm the takes place in severe COVID-19 patients, the Interleukin 6 (IL6) pathway emerges as one of the key pathways involved in the pathogenesis of this hyperinflammatory state. The strategy of blocking the inflammatory storm by targeting the IL6 is a promising therapy to mitigate mortality. The use of Tocilizumab was recommended by the World Health Organization (WHO) to treat severe COVID-19 patients. However, the efficacy of Tocilizumab is variable. We hypothesize that the genetic background could be behind the efficacy of Tocilizumab in terms of mortality.MethodsWe performed a targeted-next generation sequencing of 287 genes, of which 264 belong to a community panel of ThermoFisher for the study of genetic causes of primary immunodeficiency disorders, and 23 additional genes mostly related to inflammation, not included in the original community panel. This panel was sequenced in an initial cohort of 425 COVID-19 patients, of which 232 were treated with Tocilizumab and standard therapy, and 193 with standard therapy only. Selected genetic variants were genotyped by single base extension in additional 245 patients (95 treated with Tocilizumab and 150 non-treated with Tocilizumab). Appropriate statistical analyses and internal validation, including logistic regression models, with the interaction between Tocilizumab and genetic variants, were applied to assess the impact of these genetic variants in the efficacy of Tocilizumab in terms of mortality.ResultsAge (p < 0.001) and cardiovascular disease (p < 0.001) are risk factors for mortality in COVID-19 patients. The presence of GG and TT genotypes at IL10Rβ (rs2834167) and IL1β (rs1143633) genes significantly associates with a reduced risk of mortality in patients treated with Tocilizumab (OR = 0.111; 95%CI = 0.015–0.829; p = 0.010 and OR = 0.378; 95%CI = 0.154–0.924; p = 0.028 respectively). The presence of CC genotype at IL1RN (rs2234679) significantly associates with an increased risk of mortality, but only in patients not treated with Tocilizumab (OR = 3.200; 95%CI = 1.512–6.771; p = 0.002). Exhaustive internal validation using a bootstrap method (B = 500 replicates) validated the accuracy of the predictive models.ConclusionWe developed a series of predictive models based on three genotypes in genes with a strong implication in the etiopathogenesis of COVID-19 disease capable of predicting the risk of mortality in patients treated with Tocilizumab.

Tamsulosin is a first-line drug in the treatment of lower urinary tract symptoms (LUTS) in benign prostatic hyperplasia (BPH). Despite high estimates of its efficacy and safety, it rates may vary due to genetic polymorphisms of genes for the enzymes involved in the drugs metabolism.The aim of the work was to evaluate the carriage influence of genes polymorphisms of the CYP3A enzymes group of tamsulosin metabolizers on the efficacy and safety of therapy in patients with LUTS in BPH.Materials and methods. A total of 142 patients with LUTS, with an established BPH diagnosis (N40 according to ICD-10) were included in the study and underwent all stages. All patients received monotherapy with tamsulosin 0.4 mg/day for at least 8 weeks. An IPSS questionnaire with the definition of quality of life, a prostate ultrasound with the determination of the prostate volume and residual urine, as well as uroflowmetry, were used to evaluate the results of the treatment. Controls were performed at 2, 4 and 8 weeks from the start of the therapy. The carriage of polymorphic markers CYP3A4 (*1B, *22) and CYP3A5*3 was determined in patients; HPLC was used to determine drug concentrations in blood plasma and levels of cortisol and its metabolite 6-beta-hydroxycortisol in urine to assess the phenotypic activity of CYP3A.Results. No statistically significant associations between CYP3A phenotype (defined by CYP3A4 and CYP3A5 genotypes) and clinical parameters of the tamsulosin therapy efficacy and the safety assessment in the studied sample of patients were found (p >0.05). Similar data were obtained for individual variants of CYP3A4*1B, CYP3A4*22, CYP3A5*3 (p >0.05). The comparison of the tamsulosin residual equilibrium concentration values in patients in the study sample with respect to the carriers of CYP3A4 and CYP3A5 gene variants did not reveal the presence of significant differences in either CYP3A phenotypes and carriers and non-carriers of individual CYP3A4*1B (p=0.57), CYP3A4*22 (p=0.37) and CYP3A5*3 (p=0.76) variants. No association was found between the metabolic ratio of 6-beta-hydroxycortisol / cortisol in urine and the CYP3A phenotype encoded by a combination of genotypes of CYP3A4 and CYP3A5 gene variants (p >0.05).Conclusion. A possible association between the carriage of CYP3A4*1B, CYP3A4*22, CYP3A5*3 variants, a CYP3A activity assessed by the content of an endogenous substrate of this isoenzyme and its metabolite in urine, the level of plasma concentration of the drug, and the efficacy and safety of tamsulosin, has not been confirmed. The contribution of CYP3A4 and CYP3A5 genetic polymorphisms to clinical parameters of the tamsulosin therapy requires a further study.

Background: Allelic variants of genes encoding enzymes of the esterase system (CES1) and P-glycoprotein (ABCB1) can change the metabolism and pharmacokinetics of dabigatran. Therefore, they act as determining factors in the development of side effects, especially bleeding. We analyzed the genotype–phenotype relationship of ABCB1 (rs1045642, rs4148738, rs2032582, and rs1128503) and CES1 (rs8192935, rs71647871, and rs2244613) polymorphisms in patients with atrial fibrillation who had been treated with dabigatran. Methods: A total of 150 patients were recruited for this study. TaqMan technology was used for SNP genotyping. Results: Patients with the rs2244613 GG genotype had a lower concentration (55.27 ± 34.22 ng/ml) compared to those with the TT genotype (63.33 ± 52.25 ng/ml) (additive model, P = 0.000). Individuals with the rs8192935 AA genotype had a lower concentration (52.72 ± 30.45 ng/ml) compared to those with the GG genotype (79.78 ± 57 ng/ml) (additive model, P = 0.001). The APTT values among the different genotypes of the ABCB1 SNPs, rs4148738 and rs1045642, were significantly different (P = 0.035 and P = 0.024, respectively). Conclusion: Our research demonstrates that the CES1 polymorphisms, rs8192935 and rs2244613, are associated with the pharmacodynamics and pharmacokinetics of dabigatran in the Kazakh subpopulation.

Background. Side effects of endocrine therapy with tamoxifen (TAM) reduce the quality of life of patients with breast cancer (BC) and adversely affect treatment compliance. Against the background of treatment of BC with TAM, the risk of developing endometrial hyperplasia (EH) increases. At the moment, algorithms for monitoring patients receiving TAM by an obstetrician-gynecologist have not been developed and approved. There are also divergent opinions of experts regarding the diagnosis and management of patients in the detection of EH. This article presents the results of the final stage of the study in 2017–2022 – a survey study. The purpose of this study was to assess adherence to endocrine therapy and satisfaction with observation by a gynecologist of women with BC after 5 years of observation and their relationship with the identified early associated polymorphisms of the CYP2D6, CYP3A5, CYP2C9 and ABCB1 genes. Materials and methods. 54 patients with BC, out of 120 who had previously passed the first pharmacogenetic stage of the study, were interviewed with specially designed questionnaire. Due to the small sample size, delta percentages (∆%) were used in each comparison group with a difference threshold of 5%. To assess associations with the studied genetic polymorphisms, previously obtained significant associations of adverse drug reactions with pharmacogenetics in the same patients were used. Results. The prevalence of all adverse drug reactions (ADRs), with the exception of EH, was higher in the group of patients who canceled TAM. Over 5 years of follow-up, 57.4% of patients were regularly observed by an obstetrician-gynecologist, 42.59% of patients visited a gynecologist less than once a year. Of all the respondents, 53.7% of patients are satisfied with the regularity and quality of dispensary observation by an oncologist, 33.33% of patients are satisfied with the regularity and quality of dispensary observation by an obstetrician-gynecologist. All studied ADRs (EH, hot flashes, asthenia, bone pain and dyspepsia) associated with various genetic polymorphisms, prevailed in the group of patients who stopped taking TAM due to drug intolerance (∆%: 25.72, 6.97, 4.81, 6.97 and 24.52 respectively) compared with the TAM-group. Conclusion. The results obtained confirm the role of the studied genetic polymorphisms in the development of ADRs of TAM, but only systemic (hot flashes, asthenia, bone pain and dyspepsia). With regard to endometrial hyperplasia, no significant differences were obtained, which requires more extensive studies.

Introduction Smoking cessation is the best strategy for reducing tobacco-related morbimortality. The goal of this randomized controlled trial was to test whether using the genetically favorable markers to choose a smoking cessation drug treatment (precision medicine) was superior to using the most effective drug (varenicline) in terms of abstinence rates. Additionally, combination therapy was tested when monotherapy failed. Methods This partially blind, single-center study randomized (1:1) 361 participants into two major groups. In the genetic group (n=184), CYP2B6 rs2279343 (genotype AA) participants started treatment with bupropion, and CHRNA4 rs1044396 (genotype CT or TT) participants started treatment with varenicline; when genetic favorable to both, participants started treatment with bupropion, and when favorable to neither, on both drugs. In the control group (n=177), participants started treatment with varenicline, regardless of genetic markers. Drug treatment lasted 12 weeks. Efficacy endpoints were abstinence rates at Weeks 4, and Weeks 8–12, biochemically validated by carbon monoxide in exhaled air. Participants who did not achieve complete abstinence at Week 4, regardless of group, were given the choice to receive combination therapy. Results Abstinence rates were 42.9% (95% CI: 36–64) in the control group versus 30.4% (95% CI: 23–37) in the genetic group at Week 4 (p=0.01); and 74% (95% CI: 67–80) versus 52% (95% CI: 49–64) at Week 12 (p

Kidney transplantation stands as the ultimate recourse for restoring vital organ functions, particularly in cases of end-stage kidney disease where alternative treatments, such as dialysis, prove less effective. With over 102,000 kidney transplants conducted globally in 2022, the demand for organ transplantation is ever-increasing, fueled by a rising incidence of end-stage renal disease attributed to causes like diabetes and hypertension. Despite significant advancements in kidney transplantation, immunosuppressive therapy remains crucial to preventing graft rejection. Tacrolimus (TAC), a calcineurin inhibitor, plays a pivotal role in this regard. Discovered in 1984, TAC inhibits T-lymphocyte activation, preventing acute rejection by disrupting the transcription of crucial genes involved in early T-cell activation. However, the use of TAC is not without challenges. The drug exhibits serious side effects, a narrow therapeutic index, and unpredictable pharmacokinetics. Therapeutic drug monitoring (TDM) becomes imperative in daily practice to maintain TAC blood concentrations within the therapeutic range. This literature review delves into the genetic aspects influencing TAC metabolism, focusing on key polymorphisms in CYP3A5, CYP3A4, and ABCB1 genes. Genetic variations in CYP3A5, a major enzyme in TAC metabolism, impact enzyme activity, necessitating personalized dosing strategies. CYP3A4 polymorphisms, especially CYP3A4*22, demonstrate associations with altered TAC clearance and dose requirements. The ABCB1 gene, encoding P-glycoprotein, another player in TAC pharmacokinetics, also exhibits polymorphisms influencing drug absorption and distribution. The ABCB1 3435C>T variant, in particular, shows potential implications on Tacrolimus bioavailability. Understanding these genetic variations aids in the development of personalized dosing regimens. Studies suggest that tailoring TAC doses based on CYP3A5 genotypes significantly improves the proportion of patients achieving therapeutic concentrations. Additionally, incorporating genetic information, particularly CYP3A4*22, into dosing strategies enhances the precision of TAC therapy, reducing the risk of adverse effects.

Abstract Background CYP2C8 is responsible for the metabolism of 5% of clinically prescribed drugs, including antimalarials, anti-cancer and anti-inflammatory drugs. Genetic variability is an important factor that influences CYP2C8 activity and modulates the pharmacokinetics, efficacy and safety of its substrates. Results We profiled the genetic landscape of CYP2C8 variability using data from 96 original studies and data repositories that included a total of 33,185 unrelated participants across 44 countries and 43 ethnic groups. The reduced function allele CYP2C8*2 was most common in West and Central Africa with frequencies of 16–36.9%, whereas it was rare in Europe and Asia ( 2.3-fold) between neighboring countries and even between geographically overlapping populations. Overall, we found that 20–60% of individuals in Africa and Europe carry at least one CYP2C8 allele associated with reduced metabolism and increased adverse event risk of the anti-malarial amodiaquine. Furthermore, up to 60% of individuals of West African ancestry harbored variants that reduced the clearance of pioglitazone, repaglinide, paclitaxel and ibuprofen. In contrast, reduced function alleles are only found in

Recently, a large number of studies have been conducted to investigate the variability of response in the treatment of diabetes mellitus (T2DM), which make personalized medicine possible. However, the available data are insufficient to decide on the choice of sugar-lowering drugs in T2DM. The search for phenotypic and clinical factors of pharmacogenetic response to therapy continues. Aim of the study was to investigate the relationship between the effectiveness of sulfonylurea therapy and structural variants of the ABCC8 (rs757110) and KCNJ11 (rs5219) genes in T2DM patients with clinical phenotypes. Material and methods. A cross-sectional clinical and pharmacogenetic study of 1271 patients with T2DM receiving sulfonylurea monotherapy (SU) or in combination with metformin and divided into three clinical phenotypes: with insulin deficiency (insulinopenic phenotype), with obesity and moderate insulin resistance (classical phenotype) and with severe insulin resistance (insulin-resistant phenotype) was performed. A glycated hemoglobin content of less than 7% was considered as a good response to SU therapy. Results. Patients with a good response to SU therapy with a classic phenotype had a longer duration of diabetes compared to patients with absence of good response (5.68 ± 5.22 vs 9.12 ± 6.10 years, respectively, p < 0.001) and a later age at diagnosis of T2DM (54.05 ± 7.18 vs 49.37 ± 7.65 years, respectively, p < 0.001); patients with an insulin-resistant phenotype had T2DM established at an older age (54.35 ± 7.91 vs 50.10 ± 7.51 years, respectively, p = 0.001). Logistic regression analysis did not reveal a statistically significant association of the genotype of the structural variant of the ABCC8 gene (rs757110) with the effectiveness of SU in clinical phenotypes. The T/T genotype of the KCNJ11 gene (rs5219) was associated with a better response to SU therapy only in the group of T2DM patients with the classic phenotype (odds ratio 1.85, 95% confidence interval 1.05–3.25, p = 0.041). Conclusions. In patients with type 2 diabetes, predictors of a good response to SU with a classic phenotype were a later age of T2DM diagnosis, a shorter duration of diabetes, and the presence of the T/T genotype of the structural variant of the KCNJ11 gene (rs5219); with an insulin-resistant phenotype, a later age of T2DM diagnosis; with the insulinopenic phenotype no clinical and genetic predictors of the SU effectiveness were identified.

Fluoropyrimidines, crucial in cancer treatment, often cause toxicity concerns even at standard doses. Toxic accumulation of fluoropyrimidine metabolites, culminating in adverse effects, can stem from impaired dihydropyrimidine dehydrogenase (DPYD) enzymatic function. Emerging evidence underscores the role of single nucleotide polymorphisms (SNPs) in DPYD gene, capable of inducing DPYD activity deficiency. Consequently, DPYD genotyping’s importance is on the rise in clinical practice before initiating fluoropyrimidine treatment. Although polymerase chain reaction (PCR) followed by Sanger sequencing (SS; PCR-SS) is a prevalent method for DPYD genotyping, it may encounter limitations. In this context, there is reported a case in which a routine PCR-SS approach for genotyping DPYD SNP rs55886062 failed in a proband of African descent. The Clinical Pharmacogenetics Implementation Consortium (CPIC) categorizes the guanine (G) allele of this SNP as non-functional. The enforcement of whole genome sequencing (WGS) approach led to the identification of two adenine (A) insertions near the PCR primers annealing regions in the proband, responsible for a sequence frameshift and a genotyping error for rs55886062. These SNPs (rs145228578, 1-97981199-T-TA and rs141050810, 1-97981622-G-GA) were extremely rare in non-Finnish Europeans (0.05%) but prevalent in African populations (16%). Although limited evidence was available for these SNPs, they were catalogued as benign variants in public databases. Notably, these two SNPs exhibited a high linkage disequilibrium [LD; squared correlation coefficient (R2) = 0.98]. These findings highlighted the importance to consider the prevalence of genetic variants within diverse ethnic populations when designing primers and probes for SNP genotyping in pharmacogenetic testing. This preventive measure is essential to avoid sequence frameshifts or primer misalignments arising from SNP occurrences in the genome, which can compromise PCR-SS and lead to genotyping failures. Furthermore, this case highlights the significance of exploring alternative genotyping approaches, like WGS, when confronted with challenges associated with conventional techniques.

Abstract Background Dyslipidemia, a significant risk factor for atherosclerotic cardiovascular disease (ASCVD), is influenced by genetic variations, particularly those in the low-density lipoprotein receptor (LDLR) gene. This study aimed to elucidate the effects of LDLR polymorphisms on baseline serum lipid levels and the therapeutic efficacy of atorvastatin in an adult Han population in northern China with dyslipidemia. Methods In this study, 255 Han Chinese adults receiving atorvastatin therapy were examined and followed up. The 3’ untranslated region (UTR) of the LDLR gene was sequenced to identify polymorphisms. The associations between gene polymorphisms and serum lipid levels, as well as changes in lipid levels after intervention, were evaluated using the Wilcoxon rank sum test, with a P

Abstract Introduction Androgenetic alopecia (AGA) is a prevalent, multifactorial form of hair loss involving complex aetiological factors, such as altered androgen regulation and energy metabolism. Existing treatments offer limited success, thus highlighting the need for advanced, personalised therapeutic strategies. This study focuses on correlating the genetic mechanisms of AGA with molecular targets involved in the response to current treatment modalities. Methods An anonymised database including 26,607 patients was subjected to analysis. The dataset included information on patients’ genotypes in 26 single nucleotide polymorphisms (SNPs), specifically, and diagnosed AGA grades, representing a broad range of ethnic backgrounds. Results In our sample, 64.6% of males and 35.4% of females were diagnosed with female pattern hair loss. This distribution aligns well with prior studies, thus validating the representativeness of our dataset. AGA grading was classified using the Hamilton–Norwood and Ludwig scales, although no association was found to the grade of the disease. SNP association analysis revealed eight SNPs, namely rs13283456 (PTGES2), rs523349 (SRD5A2), rs1800012 (COL1A1), rs4343 (ACE), rs10782665 (PTGFR), rs533116 (PTGDR2), rs12724719 (CRABP2) and rs545659 (PTGDR2), to be statistically significant with a p-value below 0.05. Conclusions The study establishes a preliminary association between eight specific SNPs and AGA. These genetic markers offer insights into the variability of therapeutic responses, thus underlining the importance of personalised treatment approaches. Our findings show the potential for more targeted research to understand these SNPs’ and further roles in AGA pathophysiology and in modulating treatment response.

Aim. The aim of our study was to investigate the influence of polymorphic markers of CYP3A4*22 CYP3A4*22 (c.522-191C>T, rs35599367), CYP3A5*3 (c.219237A>G, rs776746), ABCB1 rs1045642 (c.3435T>C) and rs4148738 (c.2692-2236C>T) genes on the plasma concentration of apixaban, on changes in prothrombin time (PT), activated partial thromboplastin time (APTT), and bleeding development in patients taking apixaban.Material and methods. The study included 108 patients with non-valvular atrial fibrillation and deep vein thrombosis receiving apixaban in therapeutic doses. Genotyping was performed by real-time polymerase chain reaction. Apixaban concentrations were measured using an electrospray ionization mass spectrometer in positive ionization mode. Because the daily dose of apixaban was different (5, 10, and 20 mg daily), the residual equilibrium concentration (Cmin,ss) of apixaban was adjusted relative to the daily drug dose (Cmin,ss/D). PT and APTT were determined using an automatic coagulometer analyzer Destiny Max (Tcoag, Ireland). Statistical processing was performed in SPSS Statistics 20.0 program.Results. We found that patients with CT ABCB1 (rs4148738) C>T genotype had higher Cmin,ss /D value than patients with TT genotype (6.23 [4;13] vs 5.77 [4;17], p=0.018). No statistically significant associations were found between carriage of CYP3A4*22 (rs35599367) C>T, CYP3A5*3 A>G, ABCB1 (rs1045642) C>T gene polymorphisms and Cmin,ss /D value of apixaban. Also, there was no significant effect of carrying polymorphisms rs35599367, rs776746, rs4148738,rs4148642, and the above genes on the risks of hemorrhagic complications. However, the influence of ABCB1 (rs1045642) C>T polymorphism on the PT value was found (TT ABCB1 (rs1045642) C>T genotype carriers the CT value wassignificantly higher than in CT genotype (17.0 [40;112] vs. 14.9 [35;132]) p=0.044).Conclusion. It was found that the Cmin,ss /D value was higher in patients with CT ABCB1 (rs4148738) C>T genotype than in patients with TT genotype. At the same time, carriage of polymorphisms of CYP3A4*22 (rs35599367) C>T, CYP3A5*3 A>G, ABCB1 (rs1045642) C>T genes did not affect the pharmacokinetics of apixaban and the risk of bleeding. We also identified the effect of ABCB1 (rs1045642) C>T gene polymorphism on the PT value.

Abstract Background SLCO1B1 plays an important role in mediating hepatic clearance of many different drugs including statins, angiotensin-converting enzyme inhibitors, chemotherapeutic agents and antibiotics. Several variants in SLCO1B1 have been shown to have a clinically significant impact, in relation to efficacy of these medications. This study provides a comprehensive overview of SLCO1B1 variation in Saudi individuals, one of the largest Arab populations in the Middle East. Methods The dataset of 11,889 (9,961 exomes and 1,928 pharmacogenetic gene panel) Saudi nationals, was used to determine the presence and frequencies of SLCO1B1 variants, as described by the Clinical Pharmacogenetic Implementation Consortium (CPIC). Results We identified 141 previously described SNPs, of which rs2306283 (50%) and rs4149056 (28%), were the most common. In addition, we observed six alleles [*15 (24.7%) followed by *20 (8.04%), *14 (5.86%), *5 (3.84%), *31 (0.21%) and *9 (0.03%)] predicted to be clinically actionable. Allele diplotype to phenotype conversion revealed 41 OATP1B1 diplotypes. We estimated the burden of rare, and novel predicted deleterious variants, resulting from 17 such alterations. Conclusions The data we present, from one of the largest Arab cohorts studied to date, provides the most comprehensive overview of SLCO1B1 variants, and the subsequent OATP1B1 activity of this ethnic group, which thus far remains relatively underrepresented in available international genomic databases. We believe that the presented data provides a basis for further clinical investigations and the application of personalized statin drug therapy guidance in Arabs.

Prostate cancer remains a significant public health concern in sub-Saharan Africa, particularly impacting South Africa with high mortality rates. Despite many years of extensive research and significant financial expenditure, there has yet to be a definitive solution to prostate cancer. It is not just individuals who vary in their response to treatment, but even different nodules within the same tumor exhibit unique transcriptome patterns. These distinctions extend beyond mere differences in gene expression levels to encompass the control and networking of individual genes. Escalating chemotherapy resistance in prostate cancer patients has prompted increased research into its underlying mechanisms. The heterogeneous nature of transcriptomic organization among men makes the pursuit of universal biomarkers and one-size-fits-all treatments impractical. This study delves into the expression of drug resistance-associated genes, ABCB1 and CYP1B1, in cancer cells. Employing bioinformatics, we explored the molecular pathways and cascades linked to drug resistance following upregulation of these genes. Samples were obtained from archived prostate cancer patient specimens through pre-treatment biopsies of two categories: good vs. poor responders, with cDNAs synthesized from isolated RNAs subjected to qPCR analysis. The results revealed increased ABCB1 and CYP1B1 expression in tumor samples of the poor responders. Gene enrichment and network analysis associated ABCB1 with ABC transporters and LncRNA-mediated therapeutic resistance (WP3672), while CYP1B1 was linked to ovarian steroidogenesis, tryptophan metabolism, steroid hormone biosynthesis, benzo(a)pyrene metabolism, the sulindac metabolic pathway, and the estrogen receptor pathway, which are associated with drug resistance. Both ABCB1 and CYP1B1 correlated with microRNAs in cancer and the Nuclear Receptors Meta-Pathway. STRING analysis predicted protein–protein interactions of ABCB1 and CYP1B1 with Glutathione S-transferase Pi, Catechol O-methyltransferase, UDP-glucuronosyltransferase 1-6, Leucine-rich Transmembrane and O-methyltransferase (LRTOMT), and Epoxide hydrolase 1, with scores of 0.973, 0.971, 0.966, 0.966, and 0.966, respectively. Furthermore, molecular docking analysis of the chemotherapy drug, docetaxel, with CYP1B1 and ABCB1 revealed robust molecular interactions, with binding energies of −20.37 and −15.25 Kcal/mol, respectively. These findings underscore the susceptibility of cancer patients to drug resistance due to increased ABCB1 and CYP1B1 expression in tumor samples from patients in the poor-responders category that affects associated molecular pathways. The potent molecular interactions of ABCB1 and CYP1B1 with docetaxel further emphasize the potential basis for chemotherapy resistance.

Clopidogrel, is a standard treatment in the prevention of major adverse cardiovascular events (MACE) in patients with coronary artery disease (CAD). Clopidogrel response is highly variable, mainly due to the presence of polymorphisms in the genes involved in drug metabolism. The aim of this study was to evaluate the association between the presence of the ABCB1 C3435T and CYP2C19*2 polymorphism and the clinical outcome in patients with CAD treated with clopidogrel. A total of 96 patients with CAD were included in the study. Genomic DNA from peripheral blood was extracted from all patients with standard phenol/chloroform protocol. The genotyping was performed by Real-Time PCR using TagMan assays. The frequency of the reduced-function allele, in both genes, was higher in patients with negative outcome (36.36% vs 21.15%). A negative clinical outcome and an increased risk for MACE was observed in patients with concomitant inheritance of the CYP2C19 *1/*2 and ABCB1 CT genotype vs patients with other genotypes (22.73% vs 9.62%; OR 3.455; 95% CI= [0.936–12.743], p=0.05722. A trend towards higher risk of MACE was also noted in carriers of the CYP2C19*1/*1 and ABCB1 CC/CT genotype. Our results support the data on the association of the CYP2C19 *2 alone, or in combination with the ABCB1 C polymorphism with the increased risk of MACE. The results also indicate that the presence of ABCB1 C343T polymorphism might be potentially considered as independent predictor of MACE in patients on clopidogrel. However, these results are preliminary and should be confirmed on a larger number of patients.

The cytochrome P450 superfamily consists of hemeproteins involved in the detoxication of different xenobiotics, including drugs. The CYP2 gene family is responsible for the metabolism of 80% of the drugs in clinical use. There are considerable interindividual and interethnic variabilities in the rate of drug metabolism as a result of genetic polymorphisms. The goal of our study was to determine the frequency of 10 genetic polymorphisms in CYP2 family genes to give light on the pharmacogenetic defects of the main CYPs, involved in drug metabolism, in Bulgarian individuals. We detected high allele frequency for CYP2D6*10 (0.27), CYP2D6*4 (0.22), and CYP2B6*9 (0.24), followed by CYP2C19*2 (0.14), CYP2C9*3 (0.11) and CYP2C9*2 (0.09). The genotype frequencies were also determined for all investigated variants. In total 47.2% of the analyzed individuals carried CYP2D6 genetic polymorphisms – 5.6% carried a single variant and 41.6% were found to have two or more such variants. Homozygotes for CYP2D6 variants were established among 14% of Bulgarian individuals. Determination of the prevailing pharmacogenetic polymorphisms of the CYPs, most responsible for drug metabolism, will lead to a lower risk of drug toxicity, increased drug efficacy, and drug dose optimization.

Resumen: Antecedentes y justificación: La estrategia de la aproximación concentración-dosis (C/D) y los distintos perfiles del tacrolimus (Tac), según los polimorfismos del citocromo P450 (CYPs) se centran en el metabolismo de Tac y se plantean como herramientas para el seguimiento de los pacientes trasplantados. El objetivo de este estudio es comparar la exposición al Tac analizado según ambas estrategias. Materiales y métodos: Se han incluido 425 pacientes trasplantados renales. El cálculo del cociente concentración Tac/dosis (C/D) permitió dividir la población en terciles y clasificar los pacientes según su tasa de metabolismo del Tac en tres grupos (rápida, intermedia y lenta). Con base en los polimorfismos del CYP3A4 y A5, los pacientes se agruparon en metabolizadores rápidos (portadores del CYP3A5*1 y CYP34A *1/*1), intermedios (CYP3A5*3/3 y CYP3A4*1/*1) y lentos (CYP3A5 *3/*3 y portadores del CYP3A4*22). Resultados: Al comparar los pacientes de cada grupo metabolizador según los dos criterios, coincidieron 47% (65/139) de los metabolizadores rápidos, 85% (125/146) de los intermedios y solo 12% (17/140) de los lentos. Se observaron concentraciones de Tac estadísticamente menores en los metabolizadores rápidos y concentraciones mayores en los lentos, comparándolos con el grupo intermedio según el cociente C/D o según polimorfismos. Los metabolizadores rápidos requirieron alrededor de 60% más de dosis de Tac que los intermedios a lo largo del seguimiento, mientras que los lentos aproximadamente 20% menos de dosis que los intermedios. Los metabolizadores rápidos clasificados por ambos criterios presentan un porcentaje mayor de veces con valores de concentración de Tac en sangre infraterapéuticos. Conclusión: La determinación del fenotipo metabolizador según los polimorfismos del CYP o bien cociente C/D permite distinguir los pacientes según su exposición al Tac. Probablemente la combinación de ambos criterios de clasificación sería una buena herramienta en el manejo de la dosificación de Tac para los pacientes trasplantados. Abstract: Background and justification: The strategy of the concentration–dose (C/D) approach and the different profiles of tacrolimus (Tac) according to the cytochrome P450 polymorphisms (CYPs) focus on the metabolism of Tac and are proposed as tools for the follow-up of transplant patients. The objective of this study is to analyse both strategies to confirm whether the stratification of patients according to the pharmacokinetic behaviour of C/D corresponds to the classification according to their CYP3A4/5 cluster metabolizer profile. Materials and methods: Four hundred and twenty-five kidney transplant patients who received Tac as immunosuppressive treatment have been included. The concentration/dose ratio (C/D) was used to divided patients in terciles and classify them according to their Tac metabolism rate (fast, intermediate, and slow). Based on CYP3A4 and A5 polymorphisms, patients were classified into three metabolizer groups: fast (CYP3A5*1 and CYP34A*1/*1 carriers), intermediate (CYP3A5*3/3 and CYP3A4*1/*1) and slow (CYP3A5*3/*3 and CYP3A4*22 carriers). Results: When comparing patients included in each metabolizer group according to C/D ratio, 47% (65/139) of the fast metabolizers, 85% (125/146) of the intermediate and only 12% (17/140) of the slow also fitted in the homonym genotype group. Statistically lower Tac concentrations were observed in the fast metabolizers group and higher Tac concentrations in the slow metabolizers when compared with the intermediate group both in C/D ratio and polymorphisms criteria. High metabolizers required approximately 60% more Tac doses than intermediates throughout follow-up, while poor metabolizers required approximately 20% fewer doses than intermediates. Fast metabolizers classified by both criteria presented a higher percentage of times with sub-therapeutic blood Tac concentration values. Conclusion: Determination of the metabolizer phenotype according to CYP polymorphisms or the C/D ratio allows patients to be distinguished according to their exposure to Tac. Probably the combination of both classification criteria would be a good tool for managing Tac dosage for transplant patients.

Background and aims: Statin-associated muscle symptoms (SAMS) is a prevalent cause of statin discontinuation. It is challenging and time-consuming for clinicians to assess whether symptoms are caused by the statin or not, and diagnostic biomarkers are requested. Atorvastatin metabolites have been associated with SAMS. We aimed to compare atorvastatin pharmacokinetics between coronary heart disease (CHD) patients with and without clinically statin intolerance and statin-dependent histopathological alterations in muscle tissue. Secondarily we aimed to assess genetic variants relevant for the observed pharmacokinetic variables. Methods: Twenty-eight patients with CHD and subjective SAMS were included in the exploratory MUSE biomarker study in 2020. Participants received atorvastatin 40 mg/day for seven weeks followed by no statins for eight weeks. Muscle biopsies and blood were collected at the end of each period. Four patients were categorized as clinically intolerant to ≥3 statins prior to study start whereas four patients had signs of muscle cell damage during treatment. Results: We found significantly lower levels of atorvastatin acids, and higher lactone/acid ratios in the statin intolerant, both in muscle and plasma. With optimal cut-off, the combination of 2-OH-atorvastatin acid and the 2-OH-atorvastatin lactone/acid ratio provided sensitivity, specificity, and predictive values of 100 %. Patients with variants in UGT1A1 and UGT1A3 had higher lactone metabolite levels than those with wild type, both in muscle and plasma. Conclusion: Atorvastatin metabolites appear promising as biomarkers for the identification of clinical statin intolerance in patients with self-perceived SAMS, but the findings have to be confirmed in larger studies.

Background Pharmacogenetic testing improves the efficacy and safety of antidepressant pharmacotherapy for moderate-severe major depressive disorder by identifying genetic variations that influence medication metabolism, and adjusting treatment regimens accordingly. This study aims to assess the cost-effectiveness of implementing a pharmacogenetic testing approach to guide the prescription of antidepressants.Methods From the public hospital perspective, we developed a two-stage decision tree diagram of a short-term 6-week follow up, and a lifetime Markov model with 3-month cycles. The analysis compared the current standard of care with the alternative strategy of Pharmacogenetic-guided (multi-gene panel) testing in adult patients with moderate-severe major depressive disorder. Clinical outcomes and utilities were obtained from published studies, while healthcare costs were locally available. The short-term incremental cost-effectiveness ratio was against treatment response without side effects and without relapse, and against treatment response with/without side effects and without relapse. The long-term incremental cost-effectiveness ratio was against the quality-adjusted life year gained and years of life saved.Results Adopting the pharmacogenetic-guided therapy for adult patients with moderate-severe major depressive disorder in Qatar resulted in cost savings of Qatari Riyal 2,289 (95% confidence interval, −22,654–26,340) for the health system. In the short term, the pharmacogenetic-guided testing was associated with higher response rates without side effects and without relapse (mean difference 0.10, 95% confidence interval 0.09–0.15) and higher response rates with or without side effects and without relapse (mean difference 0.05, 95% confidence interval 0.04–0.06). For long term, the pharmacogenetic-guided testing resulted in 0.13 years of life saved and 0.06 quality-adjusted life year gained, per person, along with cost savings of Qatari Riyal 46,215 (95% confidence interval-15,744–101,758). The sensitivity analyses confirmed the robustness of the model results.Conclusion Implementing pharmacogenetic testing to guide antidepressant use was found to improve population health outcomes, while also significantly reducing health system costs.

Abstract Background Sacituzumab govitecan (sacituzumab) emerged as an important agent in metastatic and locally recurrent HER2‐negative breast cancer treatment. UGT1A1 polymorphisms have also been shown to predict sacituzumab toxicity. Methods In this retrospective study, we sought to evaluate the associations between UGT1A1 status, toxicity, and therapeutic outcomes in sacituzumab recipients with advanced breast cancer who underwent genotype testing for UGT1A1 alleles (N = 68). Results We found 17 (25%) of our patients to be homozygous for UGT1A1*28 and 24 (35.3%) were heterozygous. Of seven African American patients with triple‐negative breast cancer, five were homozygous for UGT1A1*28 and two were heterozygous. Patients with a homozygous UGT1A1*28 genotype were significantly more likely to have treatment terminated because of adverse effects. However, the polymorphism was not associated with treatment discontinuation because of disease progression. Conclusion This retrospective, real‐world analysis suggests potential clinical utility in UGT1A1 testing for patients receiving sacituzumab, but future trials are needed to confirm the association between genotypes and treatment outcomes.

ABSTRACT Objective The use of acetylsalicylic acid, even in low doses, may be associated with the onset of upper gastrointestinal bleeding as an idiosyncratic response. Considering the role of the genetic background in inter-individual responses to pharmacotherapy, we aimed to investigate the role of seven variants in the TNF-α, IL-β, and IL-1RN genes in association with the risk of upper gastrointestinal bleeding in users of low-dose acetylsalicylic acid for the prevention of cardiovascular events. Methods A case-control study was conducted in a Brazilian hospital complex. The Case Group comprised patients diagnosed with upper gastrointestinal bleeding who were administered a low dose of acetylsalicylic acid (n=50). Two Control Groups were recruited: 1) low-dose acetylsalicylic acid users without gastrointestinal complaints and under the supervision of a cardiologist (n=50) and 2) healthy controls (n=189). Sociodemographic, clinical, pharmacotherapeutic, and lifestyle data were recorded through face-to-face interviews. Genomic DNA from all participants was genotyped for rs16944 and rs1143634 (IL-β gene), rs4251961 (IL-1RN gene), and rs1799964, rs1799724, rs361525, and rs1800629 (TNF-α gene). Results No significant difference was noted in the genotypic frequencies of TNF-α, IL-β, and IL-1RN variants between the Case and Control Groups of low-dose acetylsalicylic acid users (p>0.05). The frequency of rs1800629 genotypes (TNF-α gene) differed significantly between the Case Group and healthy controls (p=0.003). None of the evaluated variants were associated with a risk of upper gastrointestinal bleeding. Conclusion This study aimed to explore pharmacogenomics biomarkers in low-dose acetylsalicylic acid users. Our data suggest that the presence of IL-1β, IL-1RN, and TNF-α variants was not associated with an increased risk of upper gastrointestinal bleeding.

BackgroundPharmacogenomics (PGx) is a well-established concept of how genes impact medication response, with many studies demonstrating reductions in medication side effects, improved efficacy and cost effectiveness. Despite these benefits, implementation of PGx in daily practice remains limited. Studies on the implementation of PGx in clinical practice have previously found that inadequate knowledge is one of the main barriers. Details regarding specifically which educational needs exist among family medicine clinicians requires further study.ObjectiveThe aim of this study was to identify both the perceived role that pharmacogenomics (PGx) could play in primary care practice, the knowledge gaps that family medicine clinicians experience, and the skills they require to use PGx in their daily practice.MethodsTo achieve this aim, the attitudes, knowledge, barriers, skills needed, and preferred educational program were explored in a family medicine clinician focus group study via a semi-structured interview and knowledge quiz. Second, multidisciplinary focus groups provided information on the level of knowledge and necessary skills to use PGx in patient care. After gathering key recorded information from both focus groups, the perceived role pharmacogenomics could possibly play in primary care, the predominant knowledge gaps, and the most appropriate educational program was determined by qualitative analysis.ResultsFour themes emerged regarding the PGx educational needs and the role of PGx in family medicine: 1) need for PGx competences, 2) insight into the roles and responsibilities of PGx services, 3) optimization of PGx workflow through artificial intelligence integrated in the electronic health record, and 4) the ethical dilemmas and psychological effects related to PGx. These themes reflect a shift in the role of PGx in family medicine with implications for education.ConclusionThe results obtained from this study will help improve the implementation of PGx in daily practice, and consequently, may result in increased utilization of PGx, thereby resulting in improved medication efficacy and reduced side effects.

Background: Several opioids have pharmacogenetic and drug-drug interactions which may compromise their analgesic effectiveness, but are not routinely implemented into supportive pain management. We hypothesized that CYP2D6 phenotypes and concomitant use of CYP2D6 substrates or inhibitors would correlate with opioid analgesic outcomes. Materials and Methods: An observational cross-sectional study was conducted with 263 adult chronic non cancer pain (CNCP) patients from a real-world pain unit under long-term CYP2D6-related opioid treatment (tramadol, hydromorphone, tapentadol or oxycodone). Metabolizer phenotype (ultrarapid [UM], normal [NM], intermediate [IM] or poor [PM]) was determined by the CYP2D6 genotype. The socio-demographic (sex, age, employment status), clinical (pain intensity and relief, neuropathic component, quality of life, disability, anxiety and depression), pharmacological (opioid doses and concomitant pharmacotherapy) and safety (adverse events) variables were recorded. Results: The whole population (66 % female, 65 (14) years old, 70 % retired and 63 % attended for low back pain) were classified as PM (5 %), IM (32 %), NM (56 %) and UM (6 %). Multiple linear and logistic regressions showed higher pain intensity and neuropathic component at younger ages when using any CYP2D6 substrate (p = 0.022) or inhibitor (p = 0.030) drug, respectively, with poorer pain relief when CYP2D6 inhibitors (p=0.030) were present. Conclusion: The concomitant use of CYP2D6 substrates or inhibitors during opioid therapy for CNCP may result in lack of analgesic effectiveness. This aspect could be relevant for pharmacological decision making during CNCP management.

Background: Current treatments for chronic hepatitis B management include orally administered nucleos(t)ide analogues, such as tenofovir (TDF), which is an acyclic adenine nucleotide analogue used both in HBV and human immune deficiency virus (HIV). The course of HBV infection is mainly dependent on viral factors, such as HBV genotypes, immunological features and host genetic variables, but a few data are available in the context of HBV, in particular for polymorphisms of genes encoding proteins involved in drug metabolism and elimination.Consequently, the aim of this study was to evaluate the potential impact of genetic variants on TDF plasma and urine concentrations in patients with HBV, considering the role of HBV genotypes. Methods: A retrospective cohort study at the Infectious Disease Unit of Amedeo di Savoia Hospital, Torino, Italy, was performed. Pharmacokinetic analyses were performed through liquidi chromatography, whereas pharmacogenetic analyses through real-time PCR. Findings: Sixty - eight patients were analyzed: ABCC4 4976 C>T genetic variant showed an impact on urine TDF drug concentrations (p = 0.014). In addition, SLC22A6 453 AA was retained in the final regression multivariate model considering factors predicting plasma concentrations, while ABCC4 4976 TC/CC was the only predictor of urine concentrations in the univariate model. Interpretation: In conclusion, this is the first study showing a potential impact of genetic variants on TDF plasma and urine concentrations in the HBV context, but further studies in different and larger cohorts of patients are required.