Pharmacogenomics in Asia: a systematic review on current trends and novel discoveries

Pharmacogenetic DPYD allele variant frequencies: A comprehensive analysis across an ancestrally diverse Iranian population

BACKGROUND

Cancer treatment has improved over the past decades, but many cancer patients still experience adverse drug reactions (ADRs). Pharmacogenomics (PGx), known as personalized treatment, is a pillar of precision medicine that aims to optimize the efficacy and safety of medications by studying the germline variations. Germline variations in the DPYD lead to significant ADRs. The present cross-sectional study aims to evaluate the allele frequency of the DPYD gene variations in the Iranian population to provide insights into personalized treatment decisions in the Iranian population.

METHODS

The allele frequency of 51 pharmacogenetic variations in the clinically relevant DPYD was assessed in a representative sample set of 1142 unrelated Iranian individuals and subpopulations of different ethnic groups who were genotyped using the Infinium Global Screening Array-24 BeadChip.

RESULTS

The genotyping assay revealed eight pharmacogenetic variants including DPYD rs1801265 (c.85T > C; DPYD*9A), rs2297595 (c.496A > G), rs1801158 (c.1601G > A; DPYD*4), rs1801159 (c.1627A > G; DPYD*5), rs1801160 (c.2194G > A; DPYD*6), rs17376848 (c.1896T > C), rs56038477 (c.1236G > A; HapB3), and rs75017182 (c.1129-5923C > G; HapB3) with minor allele frequency (MAF) ≥ 1%.

CONCLUSION

The results of the study reveal significant genetic variations among Iranian population that could significantly influence clinical decision-making. These variants, with their potential to explain the substantial variability in drug response phenotypes among different populations, shed light on a crucial aspect of pharmacogenomics. These findings not only provide valuable insights but also inspire the design and implementation of future pharmacogenomic clinical trials, motivating further research in this crucial area.

Pharmacogenomics in Sri Lanka: a comprehensive systematic review of the research landscape and clinical implications

Aim: Pharmacogenomics is emerging in South Asia, including Sri Lanka, with potential to optimize drug therapy and reduce adverse effects. This review evaluates the state of pharmacogenomics research in Sri Lanka, emphasizing population-specific factors to guide future advancements.Materials & methods: A literature search was performed across PubMed/Web-of-Science/SciVerse-Scopus/Embase, and Sri Lanka Journals Online, along with searches for relevant theses in local health repositories/university databases. Studies were categorized into clinical correlational, descriptive or novel assay development studies.Results: Eleven published articles and eight theses were included. One study examined somatic variants (KRAS gene), while all others focused on germline variants. There were two clinical correlational studies: tamoxifen adverse effects and CYP2D6 variants and FTO gene rs9939609 variants and weight gain caused by second-generation antipsychotics. Eight descriptive studies evaluated prevalence of CYP2D6 variants, HLA-B*15:02 allele, KRAS gene mutations and variants related to statin, warfarin and anticancer drug metabolism. Additionally, nine studies developed, validated and tested novel assays for detecting key pharmacogenomically important variants.Conclusion: While pharmacogenomics research in Sri Lanka has made strides, more clinical studies and broader genomic research are needed. Overcoming challenges related to funding, public awareness and regional collaboration is essential to advance personalized medicine and improve therapeutic outcomes in Sri Lanka and South Asia.

Status of the implementation of pharmacogenetics in clinical practice in Spain: from regional to national initiatives

INTRODUCTION

Pharmacogenetics (PGx) has the potential to improve patient care, allowing to transform medical interventions by providing personalized therapeutic strategies. Scientific evidence supports the use of PGx in clinical practice and international organizations are developing clinical guidelines to facilitate the utilization of PGx testing. However, clinical implementation of PGx is limited and unequal worldwide.

CONTENT

This review summarizes regional and national Spanish initiatives to implement PGx in the clinical practice.

SUMMARY AND OUTLOOK

Diverse strategies to implement PGx in healthcare are applied across countries or even in the different regions of a specific country. Such was the case of Spain, a European country with 17 Autonomous Regions and two Autonomous Cities, each one with capacity to manage their own healthcare systems. Nevertheless, during the past years, many initiatives and strategies have been launched in Spain to develop different aspects of PGx. Importantly, the National Healthcare System has approved a PGx testing catalogue. This review highlights the crucial work and efforts of scientific societies (like the Spanish Society of Pharmacogenetics and Pharmacogenomics), of experts in PGx, of healthcare providers and of governmental parties in the implementation of PGx to personalize patient therapy, focused in Spain.

Genetic ancestry in population pharmacogenomics unravels distinct geographical patterns related to drug toxicity

Genetic ancestry plays a major role in pharmacogenomics, and a deeper understanding of the genetic diversity among individuals holds immerse promise for reshaping personalized medicine. In this pivotal study, we have conducted a large-scale genomic analysis of 1,136 pharmacogenomic variants employing machine learning algorithms on 3,714 individuals from publicly available datasets to assess the risk proximity of experiencing drug-related adverse events. Our findings indicate that Admixed Americans and Europeans have demonstrated a higher risk of experiencing drug toxicity, whereas individuals with East Asian ancestry and, to a lesser extent, Oceanians displayed a lower risk proximity. Polygenic risk scores for drug-gene interactions did not necessarily follow similar assumptions, reflecting distinct genetic patterns and population-specific differences that vary depending on the drug class. Overall, our results provide evidence that genetic ancestry is a pivotal factor in population pharmacogenomics and should be further exploited to strengthen even more personalized drug therapy.

Clinical Decision Support for Precision Dosing: Opportunities for Enhanced Equity and Inclusion in Health Care

Precision dosing aims to tailor doses to individual patients with the goal of improving treatment efficacy and avoiding toxicity. Clinical decision support software (CDSS) plays a crucial role in mediating this process, translating knowledge derived from clinical trials and real-world data (RWD) into actionable insights for clinicians to use at the point of care. However, not all patient populations are proportionally represented in clinical trials and other data sources that inform CDSS tools, limiting the applicability of these tools for underrepresented populations. Here, we review some of the limitations of existing CDSS tools and discuss methods for overcoming these gaps. We discuss considerations for study design and modeling to create more inclusive CDSS, particularly with an eye toward better incorporation of biological indicators in place of race, ethnicity, or sex. We also review inclusive practices for collection of these demographic data, during both study design and in software user interface design. Because of the role CDSS plays in both recording routine clinical care data and disseminating knowledge derived from data, CDSS presents a promising opportunity to continuously improve precision dosing algorithms using RWD to better reflect the diversity of patient populations.

Implementation of HLA-B*15:02 Genotyping as Standard-of-Care for Reducing Carbamazepine/Oxcarbazepine Induced Cutaneous Adverse Drug Reactions in Thailand

Objective: This study aimed to investigate the clinical impact of HLA-B*15:02 pharmacogenomics (PGx) testing before carbamazepine (CBZ)/oxcarbazepine (OXC) prescriptions and to determine whether this PGx testing was associated with the reduction of CBZ/OXC-induced cutaneous adverse drug reactions (CADRs) in Thailand.

Methods: This retrospective observational cohort study was conducted by obtaining relevant HLA-B*15:02 PGx-testing and clinical data from electronic medical records during 2011–2020. 384 patient data were included in this study to investigate the clinical decision on CBZ/OXC usage before and after the HLA-B*15:02 PGx testing, and 1,539 patient data were included in this study to demonstrate the incidence of CBZ/OXC-induced SCARs and SJS between HLA-B*15:02 tested and non-tested patients. To analyze and summarize the results, descriptive statistics were employed, and Fisher exact test was used to compare the clinical difference between the HLA-B*15:02 positive and negative groups and to compare the differences of SCARs incidence.

Results: 384 patients were included in this study as per the inclusion criteria. Of these, 70 patients carried HLA-B*15:02, of which 63 and 65 patients were not prescribed with CBZ/OXC before and after the availability of genotyping results, respectively. In the remaining HLA-B*15:02 non-carriers, 48, and 189 patients were prescribed CBZ/OXC before and after genotyping results were available, respectively. The findings of this study showed that the incidence of SCARs of CBZ/OXC was significantly lower (p < 0.001) in the HLA-B*15:02 screening arm than in the non-screening arm.

Conclusion:HLA-B pharmacogenetics testing influenced the selection of appropriate AEDs. The presence of mild rash in the HLA-B*15:02 negative group indicates that other genetic biomarker (HLA-A*31:01) and/or non-genetic variables are involved in CBZ/OXC-induced CADRs, emphasizing that CBZ/OXC prescriptions necessitate CADR monitoring. The hospital policy and clinical decision support (CDS) alert system is essential to overcome the barriers associated with the utilization of PGx guidelines into clinical practice.

Evolution of HLA-B Pharmacogenomics and the Importance of PGx Data Integration in Health Care System: A 10 Years Retrospective Study in Thailand

Background: The HLA-B is the most polymorphic gene, play a crucial role in drug-induced hypersensitivity reactions. There is a lot of evidence associating several risk alleles to life-threatening adverse drug reactions, and a few of them have been approved as valid biomarkers for predicting life-threatening hypersensitivity reactions.

Objectives: The objective of this present study is to present the progression of HLA-B pharmacogenomics (PGx) testing in the Thai population during a 10‐year period, from 2011 to 2020.

Methods: This was a retrospective observational cohort study conducted at the Faculty of Medicine Ramathibodi Hospital. Overall, 13,985 eligible patients who were tested for HLA-B risk alleles between periods of 2011–2020 at the study site were included in this study.

Results: The HLA PGx testing has been increasing year by year tremendously, 94 HLA-B testing was done in 2011; this has been raised to 2,880 in 2020. Carbamazepine (n = 4,069, 33%), allopurinol (n = 4,675, 38%), and abacavir (n = 3,246, 26%) were the most common drugs for which the HLA-B genotyping was performed. HLA-B*13:01, HLA-B*15:02 and HLA-B*58:01 are highly frequent, HLA-B*51:01 and HLA-B*57:01 are moderately frequent alleles that are being associated with drug induced hypersensitivity. HLA-B*59:01 and HLA-B*38:01 theses alleles are rare but has been reported with drug induced toxicity. Most of the samples were from state hospital (50%), 36% from private clinical laboratories and 14% from private hospitals.

Conclusion: According to this study, HLA-B PGx testing is increasing substantially in Thailand year after year. The advancement of research in this field, increased physician awareness of PGx, and government and insurance scheme reimbursement assistance could all be factors. Incorporating PGx data, along with other clinical and non-clinical data, into clinical decision support systems (CDS) and national formularies, on the other hand, would assist prescribers in prioritizing therapy for their patients. This will also aid in the prediction and prevention of serious adverse drug reactions.

Examining key factors impact on health science students' intentions to adopt genetic and pharmacogenomics testing: a comparative path analysis in two different healthcare settings

BACKGROUND

There is an increasing interest worldwide in investigating healthcare stakeholders' perceptions and intentions to adopt pharmacogenomics (PGx) into clinical practice. However, the existing inquiries based on well-established theories and models that interpret their intentions to implement PGx are scarce. This study is the first that examines the impact of selected factors on health science students' intention to adopt genetic testing applications using the technology acceptance model while it compares two different cultural groups: Greeks (Europe; Christian) and Malays (Asia; Muslim).

RESULTS

Malay students were more persuaded about benefits of genomics for drug management compared to their Greek counterparts. However, participants from both countries appear to be particularly convinced about the benefits of genomics on disease management. Moreover, students from both countries considered the potential misuse of genetic information by corporate or government bodies as their most important concern; Greek students appeared to be considerably less worried than Malay about other probable hazards such as the deficient protection of privacy and confidentiality, which could be attributed to their religious background. Participants from both samples expressed very positive attitudes towards genetic research and testing and their favourable intentions to adopt genetic testing for personal use. Exploratory factors analysis and path analysis yielded quite similar results for both samples. Path analysis revealed that the factors of attitudes, concerns, drug management benefits and disease management benefits significantly influenced students' intentions to adopt genetic testing for personal use, with attitudes being the most inspirational factor with rather high impact, while training did not seem to affect participant's intentions. The squared multiple correlation of both models was quite satisfactory reaching to 0.55 for the Malaysian sample.

CONCLUSION

Similarities in the results of the two groups along with the relevant validity and reliability tests indicate that the proposed model is a good fit for future studies to interpret stakeholders' intentions to adopt genetic testing. Therefore, it can provide a promising and reliable basis for future model development to explain the relationships between intentions to adopt genetic testing and its predictors.

Effective early diagnosis for NSCLC: an algorithm

INTRODUCTION

Lung cancer still remains undiagnosed for most patients until the disease is inoperable.

AREAS COVERED

We performed search on PubMed with the keywords: EBUS, radial-EBUS, bronchoscopy, lung cancer, electromagnetic navigation, ct-biopsy, transthoracic biopsy. We present diagnostic equipment and imaging techniques such as positron emission tomography, endoscopical navigation systems, endobronchial ultrasound, radial-endobronchial ultrasound, transthoracic ultrasound biopsy, and computed tomography guided biopsies.

EXPERT OPINION

However, lack of early disease symptoms remains the most important issue and therefore we should direct our efforts to screening and early disease diagnosis. An algorithm is proposed for biopsy upon initial disease diagnosis.

Pharmacogenomics research and its clinical implementation in Thailand: Lessons learned from the resource-limited settings

Several barriers present challenges to implementing pharmacogenomics into practice. This review will provide an overview of the current pharmacogenomics practices and research in Thailand, address the challenges and lessons learned from delivering clinical pharmacogenomic services in Thailand, emphasize the pharmacogenomics implementation issues that must be overcome, and identify current pharmacogenomic initiatives and plans to facilitate clinical implementation of pharmacogenomics in Thailand. Ever since the pharmacogenomics research began in 2004 in Thailand, a multitude of pharmacogenomics variants associated with drug responses have been identified in the Thai population, such as HLA-B∗15:02 for carbamazepine and oxcarbazepine, HLA-B∗58:01 for allopurinol, HLA-B∗13:01 for dapsone and cotrimoxazole, CYP2B6 variants for efavirenz, CYP2C9∗3 for phenytoin and warfarin, CYP3A5∗3 for tacrolimus, and UGT1A1∗6 and UGT1A1∗28 for irinotecan, etc. The future of pharmacogenomics guided therapy in clinical settings across Thailand appears promising because of the availability of evidence of clinical validity of the pharmacogenomics testing and support for reimbursement of pharmacogenomics testing.

Review on Databases and Bioinformatic Approaches on Pharmacogenomics of Adverse Drug Reactions

Pharmacogenomics has been used effectively in studying adverse drug reactions by determining the person-specific genetic factors associated with individual response to a drug. Current approaches have revealed the significant importance of sequencing technologies and sequence analysis strategies for interpreting the contribution of genetic variation in developing adverse reactions. Advance in next generation sequencing and platform brings new opportunities in validating the genetic candidates in certain reactions, and could be used to develop the preemptive tests to predict the outcome of the variation in a personal response to a drug. With the highly accumulated available data recently, the in silico approach with data analysis and modeling plays as other important alternatives which significantly support the final decisions in the transformation from research to clinical applications such as diagnosis and treatments for various types of adverse responses.

What Do Students in Pharmacy and Medicine Think About Pharmacogenomics and Personalized Medicine Education? Awareness, Attitudes, and Perceptions in Malaysian Health Sciences

This study reports on the attitudes and perceptions toward pharmacogenomics (PGx) and personalized medicine (PM) education among pharmacy and medical students in Malaysian health sciences. Importantly, the survey was developed through a codesign approach, with field pretesting/design with users before the actual survey, and based on collaboration between institutions in Greece and Malaysia. The study addressed eight key areas of interest to education in health sciences: (1) General awareness about genetics and PGx, (2) Attitude toward genetic testing usefulness, (3) Benefits of direct-to-consumer personal genome testing as a "diagnostic" tool, (4) Concerns (risks) about genetics, (5) Effectiveness of genetic testing in PM, (6) Benefits of PGx on disease management, (7) Benefits of PGx on drug management, and (8) Attitudes toward genetic testing public endorsement. We observed that Malaysian students appear aware of the term PGx, but there are areas of critical knowledge gap such as the need for greater familiarity with the concept of PGx implementation science, and the availability of genetic testing in clinical practice. This is one of the first studies on perceptions and attitudes toward PGx testing in Southeast Asia. The present findings provide a map of the views and perspectives of medicine and pharmacy students regarding PGx and implementation of PM in Malaysia and should assist toward facilitating the integration of genomics into the medical decision-making process. To this end, it is necessary to enhance collaboration between universities, health care institutions, and governing bodies to incorporate further training and additional education topics related to PGx and genetic testing. This is the first study that assesses the level of PGx and genomics knowledge of pharmacy and medicine students in Southeast Asia, Malaysia in particular, and thus paves the way to guide future global PGx implementation science.

Pharmacogenomics in Asian Subpopulations and Impacts on Commonly Prescribed Medications

Asians as a group comprise > 60% the world's population. There is an incredible amount of diversity in Asian and admixed populations that has not been addressed in a pharmacogenetic context. The known pharmacogenetic differences in Asian subgroups generally represent previously known variants that are present at much lower or higher frequencies in Asians compared with other populations. In this review we summarize the main drugs and known genes that appear to have differences in their pharmacogenetic properties in certain Asian populations. Evidence-based guidelines and summary statistics from the US Food and Drug Administration and the Clinical Pharmacogenetics Implementation Consortium were analyzed for ethnic differences in outcomes. Implicated drugs included commonly prescribed drugs such as warfarin, clopidogrel, carbamazepine, and allopurinol. The majority of these associations are due to Asians more commonly being poor metabolizers of cytochrome P450 (CYP) 2C19 and carriers of the human leukocyte antigen (HLA)-B*15:02 allele. The relative risk increase was shown to vary between genes and drugs, but could be > 100-fold higher in Asians. Specifically, there was a 172-fold increased risk of Stevens-Johnson syndrome and toxic epidermal necrolysis with carbamazepine use among HLA-B*15:02 carriers. The effects ranged from relatively benign reactions such as reduced drug efficacy to severe cutaneous skin reactions. These reactions are severe and prevalent enough to warrant pharmacogenetic testing and appropriate changes in dose and medication choice for at-risk populations. Further studies should be done on Asian cohorts to more fully understand pharmacogenetic variants in these populations and to clarify how such differences may influence drug response.

Conference report: pharmacogenomics in special populations at WCP2018

The 18th World Congress of Basic and Clinical Pharmacology (WCP2018), coordinated by IUPHAR and hosted by the Japanese Pharmacological Society and the Japanese Society of Clinical Pharmacology and Therapeutics, was held in July 2018 at the Kyoto International Conference Center, in Kyoto, Japan. Having as its main theme 'Pharmacology for the Future: Science, Drug Development and Therapeutics', WCP2018 was attended by over 4500 delegates, representing 78 countries. The present report is an overview of a symposium at WCP2018, entitled Pharmacogenomics in Special Populations, organized by IUPHAR´s Pharmacogenetics/Genomics (PGx) section. The PGx section congregates distinguished scientists from different continents, covering expertise from basic research, to clinical implementation and ethical aspects of PGx, and one of its major activities is the coordination of symposia and workshops to foster exchange of PGx knowledge (https://iuphar.org/sections-subcoms/pharmacogenetics-genomics/). The symposium attracted a large audience to listen to presentations covering various areas of research and clinical adoption of PGx in Oceania, Africa, Latin America and Asia.

Polymorphism Of The APM1 Gene In Subjects With Central Obesity Related To Lower High-Density Lipoprotein Cholesterol

BACKGROUND

Central obesity is a risk factor for metabolic syndrome. Subjects with central obesity have a higher risk of developing type 2 diabetes and cardiovascular disease. Many conditions affect the prevalence of central obesity, including energy expenditure, aging, proinflammatory conditions, and hormonal, genetic, and ethnic differences. Polymorphism of the APM1 gene, encoding the protein adiponectin, is closely related to metabolic syndrome. Adiponectin influences fatty acid oxidation and glucose intake in muscle. Therefore, variation in the APM1 gene is associated with diabetes and obesity.

PURPOSE

The aim of the present study was to investigate the correlation of the single-nucleotide polymorphism (SNP) of the APM1 SNP rs2241766 with body mass index (BMI) and lipid profiles in Indonesian (Bandung) subjects.

PATIENTS AND METHODS

Genotyping of the APM1 gene was performed using the Amplification Refractory Mutation System. Whole blood and serum of 54 subjects with central obesity (waist circumference [WC] ≥90 cm) and 53 healthy subjects (WC <90 cm) were collected. Measurements of the lipid profile (low-density lipoprotein [LDL], high-density lipoprotein [HDL], and total cholesterol [TC]) and BMI were examined.

RESULTS

The TT and GT genotype were observed (no GG genotype) in all subjects. The TC, LDL, fasting blood glucose, and BMI did not show a significant correlation between genotype variations of APM1 with central obesity. Otherwise, subjects with central obesity with the TT genotype had lower HDL levels than those with the GT genotype (p = 0.014, significant OR 1.045; 95% CI).

CONCLUSION

This finding suggests that the T allele of the APM1 SNP rs2241766 is dominant in the Bandung population, and subjects with the homozygous TT genotype have a higher incidence of metabolic disorder.

Allelic frequencies of 60 pharmacogene variants assessed within a Burmese population residing in northeast Indiana, USA

AIM

The aim of this study was to investigate 60 SNPs pertaining to drug metabolism and pharmacodynamics in the Burmese refugee population in the Fort Wayne, Indiana area to better inform patient care.

MATERIALS & METHODS

Sixty-two self-identified Burmese refugees were genotyped for 60 common SNPs pertaining to pharmacokinetic and pharmacodynamic pharmacogenes. The resulting allelic frequencies were compared with Ensembl's database for surrounding populations to Myanmar and America.

RESULTS

The frequency of OPRM1, CYP2D6, SLCO1B1, MTHFR and VKORC1 were approximately 20% different in the Burmese refugee population as compared with the Ensembl populations.

CONCLUSION

Our study demonstrates that genetic differences are expected to affect drug efficacy in patients with a Burmese background.