Pharmacogenomic Variation Research Articles

Pharmacogenomic Variation in Antiplatelet and Anticoagulant Medication Response: Data from the Multi-Ethnic New Zealand Study of Acute Coronary Syndromes

Pharmacogenomic Variation in Antiplatelet and Anticoagulant Medication Response: Data from the Multi-Ethnic New Zealand Study of Acute Coronary Syndromes

The Role of CYPs and Transporters in the Biotransformation and Transport of the Anti-hepatitis C Antiviral Agents Asunaprevir, Daclatasvir, and Beclabuvir: Impact of Liver Disease, Race and Drug-drug Interactions on Safety and Efficacy.

Asunaprevir, daclatasvir, and beclabuvir are direct-acting antiviral agents used in the treatment of patients infected with hepatitis C genotype 1b. This article reviews the biotransformation and disposition of these drugs in relation to the safety and efficacy of therapy. CYP3A4 and 3A5 catalyze the oxidative biotransformation of the drugs, while P-glycoprotein mediates their efflux from tissues. Asunaprevir is also a substrate for the influx transporters OATP1B1 and OATP2B1 and the efflux transporter MRP2, while beclabuvir is also a substrate for the efflux transporter BCRP. Liver disease decreases the expression of CYPs and transporters that mediate drug metabolism and disposition. Serum asunaprevir concentrations, but not those of daclatasvir or beclabuvir, are increased in patients with severe liver disease, which may produce toxicity. Pharmacogenomic variation in CYPs and transporters also has the potential to disrupt therapy with asunaprevir, daclatasvir and beclabuvir; some variants are more prevalent in certain racial groups. Pharmacokinetic drug-drug interactions, especially where asunaprevir, daclatasvir, and beclabuvir are victim drugs, are mediated by coadministered rifampicin, ketoconazole and ritonavir, and are attributable to inhibition and/or induction of CYPs and transporters. Conversely, there is also evidence that asunaprevir, daclatasvir and beclabuvir are perpetrators of drug interactions with coadministered rosuvastatin and dextromethorphan. Together, liver disease, pharmacogenomic variation and drug-drug interactions may disrupt therapy with asunaprevir, daclatasvir and beclabuvir due to the impaired function of important CYPs and transporters.

Pharmacogenomic Variation May Impact Cyclophosphamide Metabolism and Graft Status after HCT for Sickle Cell Disease

Pharmacogenomic Variation May Impact Cyclophosphamide Metabolism and Graft Status after HCT for Sickle Cell Disease

Cyclophosphamide Pharmacogenomic Variation in Cancer Treatment and Its Effect on Bioactivation and Pharmacokinetics.

Cyclophosphamide (Cy) is a prodrug that is mainly bioactivated by cytochrome P450 (CYP) 2B6 enzyme. Several other enzymes are also involved in its bioactivation and affect its kinetics. Previous studies have shown the effect of the enzymes' genetic polymorphisms on Cy kinetics and its clinical outcome. These results were controversial primarily because of the involvement of several interacting enzymes in the Cy metabolic pathway, which can also be affected by several clinical factors as well as other drug interactions. In this review article, we present the effect of CYP2B6 polymorphisms on Cy kinetics since it is the main bioactivating enzyme, as well as discussing all previously reported enzymes and clinical factors that can alter Cy efficacy. Additionally, we present explanations for key Cy side effects related to the nature and site of its bioactivation. Finally, we discuss the role of busulphan in conditioning regimens in the Cy metabolic pathway as a clinical example of drug-drug interactions involving several enzymes. By the end of this article, our aim is to have provided a comprehensive summary of Cy pharmacogenomics and the effect on its kinetics. The utility of these findings in the development of new strategies for Cy personalized patient dose adjustment will aid in the future optimization of patient specific Cy dosages and ultimately in improving clinical outcomes. In conclusion, CYP2B6 and several other enzyme polymorphisms can alter Cy kinetics and consequently the clinical outcomes. However, the precise quantification of Cy kinetics in any individual patient is complex as it is clearly under multifactorial genetic control. Additionally, other clinical factors such as the patient's age, diagnosis, concomitant medications, and clinical status should also be considered.

429 Impact of pharmacogenomic variation on elexacaftor-tezacaftorivacaftor concentrations in people with cystic fibrosis

429 Impact of pharmacogenomic variation on elexacaftor-tezacaftorivacaftor concentrations in people with cystic fibrosis

Population Pharmacogenomics for Health Equity.

Health equity means the opportunity for all people and populations to attain optimal health, and it requires intentional efforts to promote fairness in patient treatments and outcomes. Pharmacogenomic variants are genetic differences associated with how patients respond to medications, and their presence can inform treatment decisions. In this perspective, we contend that the study of pharmacogenomic variation within and between human populations-population pharmacogenomics-can and should be leveraged in support of health equity. The key observation in support of this contention is that racial and ethnic groups exhibit pronounced differences in the frequencies of numerous pharmacogenomic variants, with direct implications for clinical practice. The use of race and ethnicity to stratify pharmacogenomic risk provides a means to avoid potential harm caused by biases introduced when treatment regimens do not consider genetic differences between population groups, particularly when majority group genetic profiles are assumed to hold for minority groups. We focus on the mitigation of adverse drug reactions as an area where population pharmacogenomics can have a direct and immediate impact on public health.

Race, Ethnicity, and Pharmacogenomic Variation in the United States and the United Kingdom.

The relevance of race and ethnicity to genetics and medicine has long been a matter of debate. An emerging consensus holds that race and ethnicity are social constructs and thus poor proxies for genetic diversity. The goal of this study was to evaluate the relationship between race, ethnicity, and clinically relevant pharmacogenomic variation in cosmopolitan populations. We studied racially and ethnically diverse cohorts of 65,120 participants from the United States All of Us Research Program (All of Us) and 31,396 participants from the United Kingdom Biobank (UKB). Genome-wide patterns of pharmacogenomic variation-6311 drug response-associated variants for All of Us and 5966 variants for UKB-were analyzed with machine learning classifiers to predict participants' self-identified race and ethnicity. Pharmacogenomic variation predicts race/ethnicity with averages of 92.1% accuracy for All of Us and 94.3% accuracy for UKB. Group-specific prediction accuracies range from 99.0% for the White group in UKB to 92.9% for the Hispanic group in All of Us. Prediction accuracies are substantially lower for individuals who identified with more than one group in All of Us (16.7%) or as Mixed in UKB (70.7%). There are numerous individual pharmacogenomic variants with large allele frequency differences between race/ethnicity groups in both cohorts. Frequency differences for toxicity-associated variants predict hundreds of adverse drug reactions per 1000 treated participants for minority groups in All of Us. Our results indicate that race and ethnicity can be used to stratify pharmacogenomic risk in the US and UK populations and should not be discounted when making treatment decisions. We resolve the contradiction between the results reported here and the orthodoxy of race and ethnicity as non-genetic, social constructs by emphasizing the distinction between global and local patterns of human genetic diversity, and we stress the current and future limitations of race and ethnicity as proxies for pharmacogenomic variation.

Pharmacogenomic variation in the Malagasy population: implications for the antimalarial drug primaquine metabolism.

Aim: Antimalarial primaquine (PQ) eliminates liver hypnozoites of Plasmodium vivax.CYP2D6 gene variation contributes to PQ therapeutic failure. Additional gene variation may contribute to PQ efficacy. Information on pharmacogenomic variation in Madagascar, with vivax malaria and a unique population admixture, is scanty. Methods: The authors performed genome-wide genotyping of 55 Malagasy samples and analyzed data with a focus on a set of 28 pharmacogenes most relevant to PQ. Results: Mainly, the study identified 110 coding or splicing variants, including those that, based on previous studies in other populations, may be implicated in PQ responseand copy number variation, specifically in chromosomal regions that contain pharmacogenes. Conclusion: With this pilot information, larger genome-wide association analyses with PQ metabolism and response are substantially more feasible.

285 Genetic Variation in the SLC22A1-3 Genes Influence the Risk of Congenital Anomalies

OBJECTIVES/GOALS: Congenital anomalies (CA) are common, but the cause is often unknown. The interplay between known environmental teratogens, such as medication use in pregnancy, and genetic predisposition impacts CA risk, but such interactions are poorly understood. We test the hypothesis that pharmacogenomic (PGx) variation impacts CA risk. METHODS/STUDY POPULATION: We performed a drug absorption, distribution, metabolism, and excretion (ADME) gene-wide association study (GWAS), which tests for a possible association between ADME gene single nucleotide polymorphisms and individuals with CAs. This analysis was performed in BioVU and utilized billing codes to identify 5,845 cases, individuals with at least one CA, and 50,059 controls of genetically European ancestry. Using Plink software we analyzed 5,398 SNPs in 292 ADME genes across cases and controls. Results from this analysis drove us to further investigate the association between CA risk and SLC22A1-3. Next, we performed PrediXcan analyses to estimate the association between genetically predicted gene expression (GPGE) of SLC22A1-3 genes across all available tissues in the GTEx resource and CA risk. RESULTS/ANTICIPATED RESULTS: The ADME GWAS identified multiple variants on chromosome 6 in the region of SCL22A1-3 that were associated with the risk for CAs. The most significant variants were rs2048327, rs2292334, rs3088442, rs1810126, rs376563, and rs7758229, p DISCUSSION/SIGNIFICANCE: The combination of the known crucial pharmacological roles of OCT1-3 and the results of our ADME GWAS / PrediXcan analyses demonstrates that PGx burden, specifically variation in the SLC22A1-3 genes, influences the risk of developing CAs. This new understanding has the potential to personalize care for pregnant individuals to reduce the risk of CAs.

A population study of clinically actionable genetic variation affecting drug response from the Middle East

Clinical implementation of pharmacogenomics will help in personalizing drug prescriptions and alleviate the personal and financial burden due to inefficacy and adverse reactions to drugs. However, such implementation is lagging in many parts of the world, including the Middle East, mainly due to the lack of data on the distribution of actionable pharmacogenomic variation in these ethnicities. We analyzed 6,045 whole genomes from the Qatari population for the distribution of allele frequencies of 2,629 variants in 1,026 genes known to affect 559 drugs or classes of drugs. We also performed a focused analysis of genotypes or diplotypes of 15 genes affecting 46 drugs, which have guidelines for clinical implementation and predicted their phenotypic impact. The allele frequencies of 1,320 variants in 703 genes affecting 299 drugs or class of drugs were significantly different between the Qatari population and other world populations. On average, Qataris carry 3.6 actionable genotypes/diplotypes, affecting 13 drugs with guidelines for clinical implementation, and 99.5% of the individuals had at least one clinically actionable genotype/diplotype. Increased risk of simvastatin-induced myopathy could be predicted in ~32% of Qataris from the diplotypes of SLCO1B1, which is higher compared to many other populations, while fewer Qataris may need tacrolimus dosage adjustments for achieving immunosuppression based on the CYP3A5 diplotypes compared to other world populations. Distinct distribution of actionable pharmacogenomic variation was also observed among the Qatari subpopulations. Our comprehensive study of the distribution of actionable genetic variation affecting drugs in a Middle Eastern population has potential implications for preemptive pharmacogenomic implementation in the region and beyond.

Genetic Ancestry Inference for Pharmacogenomics.

Genetic ancestry inference can be used to stratify patient cohorts and to model pharmacogenomic variation within and between populations. We provide a detailed guide to genetic ancestry inference using genome-wide genetic variant datasets, with an emphasis on two widely used techniques: principal components analysis (PCA) and ADMIXTURE analysis. PCA can be used for patient stratification and categorical ancestry inference, whereas ADMIXTURE is used to characterize genetic ancestry as a continuous variable. Visualization methods are critical for the interpretation of genetic ancestry inference methods, and we provide instructions for how the results of PCA and ADMIXTURE can be effectively visualized.

The Apportionment of Pharmacogenomic Variation: Race, Ethnicity, and Adverse Drug Reactions.

Fifty years ago, Richard Lewontin found that the vast majority of human genetic variation falls within (~85%) rather than between (~15%) racial groups. This result has been replicated numerous times since and is widely taken to support the notion that genetic differences between racial groups are trivial and thus irrelevant for clinical decision-making. The aim of this study was to consider how the apportionment of pharmacogenomic variation within and between racial and ethnic groups relates to risk disparities for adverse drug reactions. We confirmed that the majority of pharmacogenomic variation falls within (97.3%) rather than between (2.78%) the three largest racial and ethnic groups in the United States: Black, Hispanic, and White. Nevertheless, pharmacogenomic variants showing far greater within than between-group variation can have high predictive value for adverse drug reactions, particularly for minority racial and ethnic groups. We predicted excess adverse drug reactions for minority Black and Hispanic groups, compared to the majority White group, and considered these results in light of the apportionment of genetic variation within and between groups. For 85% within and 15% between group variation, there are 700 excess adverse drug reactions per 1,000 patients predicted for a recessive effect model and 300 for a dominant model. We found high numbers of predicted Black and Hispanic excess adverse drug reactions for widely prescribed platinum chemotherapy compounds, such as cisplatin and oxaliplatin, as well as controlled narcotics, including fentanyl and tramadol. Our results indicate that race and ethnicity, while imprecise proxies for genetic diversity, correlate with patterns of pharmacogenomic variation in a way that is clearly relevant to medical treatment decisions. The effects of this variation is particularly pronounced for Black and Hispanic minority groups, owing to genetic differences from the majority White group. Treatment decisions that are made based on (assumed) White pharmacogenomic variant frequencies can be harmful for minority groups. Ignoring clinically relevant genetic differences among racial and ethnic groups, however well-intentioned, will exacerbate rather than ameliorate health disparities.

Dietary supplements, cytochrome metabolism, and pharmacogenetic considerations.

Dietary supplement use has continued to rise. In addition to supplement-drug interactions, it is prudent to consider how dietary supplements may interact with a patient's specific pharmacogenetics. Variations in genes associated with CYP 450 enzymes have evidence of impacting drug metabolism and adverse effects. This research was performed to evaluate CYP P450 enzyme activity of the top 15 dietary supplements used in the USA in order to initiate pharmacogenetic considerations specific to commonly used dietary supplements. The most common dietary supplements used in the USA were obtained from the National Health and Nutrition Examination Survey (NHANES). Primary literature detailing supplement CYP P450 activity was compiled from PubMed using MeSH search terms: supplement name(s), cytochrome P450 enzymes, metabolism, and pharmacokinetics. Additional resources utilized for documented CYP enzyme genotypes were the pharmacogenetic databases from Clinical Pharmacogenetics Implementation Consortium and The Pharmacogenomic Variation Consortium. Of the 15 most common dietary supplements used in the USA, 53% (cranberry, echinacea, garlic, ginkgo biloba, ginseng, melatonin, milk thistle, and valerian) exhibit CYP P450 metabolism, with some having possible induction activity as well. Melatonin and garlic are substrates of CYP1A2 and CYP2C19, respectively. Additionally, there is evidence of echinacea having possible CYP3A4 induction activity. CYP P450 activity is an important consideration for any patient but becomes increasingly critical if patients have certain CYP P450 phenotypes that impact metabolism. These popular supplements have the potential for changes in supplement exposure, and adverse effects based on pharmacogenetic profiles. Furthermore, these sites of metabolism are shared with many medications, setting the stage for possibly more profound interactions between medications and supplements. This paper highlights the mechanisms in which dietary supplements may constitute a risk for patients with certain CYP P450 phenotypes. Further research is needed in the area of dietary supplements and their pharmacogenomic implications.

127 Impact of CYP2D6, CYP3A4, and CYP2C9 pharmacogenomic profile on pain relief and adverse events in Canadian children treated with oxycodone and ibuprofen

Abstract Primary Subject area Clinical Pharmacology and Toxicology Background Genomic variation impacts drug pharmacokinetics for commonly used children’s pain medications such as oxycodone and ibuprofen. In order to personalize and best treat children’s pain, how cytochrome enzyme polymorphisms for CYP2D6, CYP3A4, and CYP2C9 impact clinical effectiveness and safety for oxycodone and ibuprofen were studied. Objectives Primary objectives were to evaluate if allelic variations of CYP2D6, CYP2C9, and CYP3A4 would a) alter clinical effectiveness of ibuprofen and oxycodone for pain relief, and b) impact the occurrence of adverse events. Secondary objectives were to determine the degree to which these genetic and other clinical factors influence analgesic effectiveness and safety. Design/Methods This prospective, observational cohort included children aged 4-16 years who were seen in a pediatric emergency department (between June 2010 - July 2014) with an acute fracture and used ibuprofen OR oxycodone for at-home pain management. Saliva samples were obtained prior to discharge, and daily telephone follow-up collected self-reported pain scores, medication use, adverse events, and functional limitations for 3 days. Genotyping identified allelic variants of CYP2D6, CYP3A4, and CYP2C9. Pain was measured using the Faces Pain Scale-Revised. CYP2D6 metabolic phenotypes were determined based on identified variants. Regression analyses were employed to determine relationships between clinical and genomic patient characteristics, pain relief, and adverse events. Results We included 210 children (n=140 ibuprofen, n=70 oxycodone); mean age was 11.1 (±3.5) years, 66.2% were male, and 79.5% self-identified as Caucasian. The median pain reduction in the ibuprofen group was 4 (±2.0) and 4 (±3.5) in the oxycodone group on Day 1 (p = 0.69). Adverse events were experienced by 53.2% of the ibuprofen group and 78.3% of the oxycodone group (p < 0.001). CYP2D6 Intermediate Metabolizers had significantly less pain relief using oxycodone than Extensive Metabolizers (p = 0.04). CYP3A4 variants did not significantly impact pain relief or adverse events. Those with the decreased functioning CYP2C9*2 allele experienced less adverse events compared to the normal functioning allele CYP2C9*1 (p = 0.003) when using ibuprofen. Males (p = 0.035) and all children using non-pharmacological pain strategies (p = 0.02) experienced less pain relief with oxycodone. Conclusion A better understanding of pharmacogenomic variation could help personalize medication choice. Sex and non-pharmacologic pain management impact pain relief with oxycodone, warranting further study to better understand their relationship with opioid pain relief in children.

54443 Pharmacogenomic Profiling of East and West African Populations

ABSTRACT IMPACT: Genomic variation likely plays a role in differences in rates of adverse reactions and efficacy for African populations, and this research will add to the understudied field of pharmacogenomics in African populations. OBJECTIVES/GOALS: We aim to characterize the frequency of variants in clinically relevant genes in East and West African populations to assess the prevalence of potential drug-gene interactions. METHODS/STUDY POPULATION: Our pilot study will consist of 100 Somali patients enrolled at Mayo Clinic Rochester and 100 Ghanaian patients recruited at Teaching Hospitals in Ghana. Germline DNA will be extracted from pre-existing blood samples. Sequencing will be performed using Admera Health’s PGxOne Plus test, interrogating a panel of 62 genes. Variants will be reported along with the predicted response for a list of drugs. Differences between frequencies of variants in East and West African populations will be analyzed. We will look for correlations with reported adverse reaction rates. We will then compare our findings with allele frequency data from publicly available data bases. Additionally, we will analyze the flanking regions of the panel for novel variants, using machine learning to predict gene-drug interactions. RESULTS/ANTICIPATED RESULTS: African populations are known to have more genetic diversity than any other population. Additionally, only African-Americans, African-Caribbeans from Barbados, Esan and Yoruba Nigerians, Gambians, Kenyans, and Sierra Leoneans are accounted for within the publicly available data bases most often used for variant studies. Thus, it is anticipated that we will find differences in the variant allele frequencies of our populations compared to European allele frequencies, and differences in frequencies between the East and West African populations. In the 200 base pair flanking regions that are sequenced in the assay along with the known variant regions, we may find novel previously unreported variants. DISCUSSION/SIGNIFICANCE OF FINDINGS: The lack of knowledge of pharmacogenomic variation in African populations contributes to ethnic disparities in patient outcomes. This study addresses this gap by adding to our comprehension of variants in clinically relevant genes, giving insight into underlying mechanisms of ethnicity-based drug responses.

Impact of Pharmacogenomic Information on Values of Care and Quality of Life Associated with Codeine and Tramadol-Related Adverse Drug Events

ObjectiveTo assess the potential impact of Pharmacogenomic (PGx) variation in cytochrome P450 2D6 (CYP2D6) enzyme function, using loss in quality-adjusted life years (QALYs) associated with treatment problems, and the willingness to pay to avoid treatment problems from patients’ and payers’ perspectives. Patients and MethodsThe study included patients prescribed tramadol or codeine, or both, between January 1, 2005, and December 31, 2017. Demographic information and adverse drug events, including adverse drug events and poor pain control, were collected from the electronic health records using natural language processing techniques and review by trained abstractors. Patients’ willingness to pay and QALY estimates were based on comprehensive literature review. The CYP2D6 phenotypes were divided into 4 groups: ultra-rapid metabolizers, normal metabolizers, intermediate metabolizers, and poor metabolizers. ResultsAmong the 2860 identified patients, 63 (2%) were ultrarapid metabolizers, 1449 (50%) were normal metabolizers, 1155 (40%) were intermediate metabolizers, and 193 (7%) were poor metabolizers. The patients’ average estimated willingness-to-pay value to avoid treatment problems was $23 per month; poor metabolizers developed problems with the highest estimated willingness-to-pay value ($32 per month). The mean QALY loss among all patients was 0.024 QALYs (8.8 healthy days); poor metabolizers had the highest loss (0.027 QALYs, 9.9 healthy days). ConclusionPatients with various phenotypes developed different treatment problem profiles. Poor CYP2D6 metabolizers developed problems with highest willingness to pay, and they might potentially benefit most from PGx-guided treatment and problem prevention.

Genetic variation in alcoholism and opioid addiction susceptibility and treatment: a pharmacogenomic approach

<abstract> <p>Alcohol and opioid abuse have pervasive and detrimental consequences from the individual to societal level. The extent of genetic contribution to alcoholism has been studied for decades, yielding speculative and often inconsistent results since the previous discovery of two pharmacokinetic variants strongly protective against alcoholism. The neurobiology of addiction involves innumerate genes with combinatorial and epistatic interactions, creating a difficult landscape for concrete conclusions. In contrast, pharmacogenomic variation in the treatment of alcoholism yields more immediate clinical utility, while also emphasizing pathways crucial to the progression of addiction. An improved understanding of genetic predisposition to alcohol abuse has inherent significance for opioid addiction and treatment, as the two drugs induce the same reward pathway. This review outlines current knowledge, treatments, and research regarding genetic predisposition to alcoholism, focusing on pharmacodynamic variation within the dopaminergic system and shared implications for opioid abuse. Multifaceted and highly polygenic, the phenotype of addiction seems to grow more complex as new research extends the scope of its impact on the brain, body, and progeny.</p> </abstract>

Evaluation of Tacrolimus Levels and Risk of Graft-Versus-Host Disease, Relapse and Non-Relapse Mortality after Haploidentical Transplantation with Post-Transplant Cyclophosphamide

Following haploidentical hematopoietic cell transplantation (haplo-HCT) with post-transplant cyclophosphamide (PTCy), the range of target tacrolimus blood levels is wide (5-15 ng/ml). This fact, combined with pharmacogenomic variation and effects of drug interactions, leads to significant variability in tacrolimus serum concentrations. In the setting of matched related or unrelated donor transplantation using conventional graft-versus-host disease (GVHD) prophylaxis, several published studies have correlated higher post-transplant tacrolimus levels with a lower risk of GVHD. Therefore, we hypothesized that early post-transplant tacrolimus levels following haplo-HCT might impact the incidence of GVHD and other post-transplant endpoints and that more precise tacrolimus level targeting may improve post-transplant outcomes. To this end, we analyzed the relationship between mean weekly tacrolimus levels and acute and chronic GVHD, relapse, non-relapse mortality (NRM) and survival in 158 consecutive patients with hematologic malignancies receiving haplo-HCT using PTCy, tacrolimus and mycophenolate for GVHD prophylaxis between 2013-2018. Transplanted patients had a median age of 51 years (range, 19-75) and comorbidity index was ≥3 in 97 (61%). Peripheral blood was the graft source in 142 (90%), and regimen intensity was myeloablative in 90 (57%). Mean weekly tacrolimus levels were calculated each week for the first 4 weeks starting on day +7 and ending day +35 post-transplant, as well as aggregate mean tacrolimus level for 2- and 4-week intervals. Table 1 depicts a summary of the univariate analysis of weekly mean tacrolimus levels and various clinical endpoints (hazard ratios are depicted for each 1 ng/ml increment in mean tacrolimus levels). In this analysis, there were no significant associations between higher mean weekly tacrolimus levels and acute GVHD, chronic GVHD, relapse, NRM, or survival. Using tertiles, mean tacrolimus levels during weeks 1-4 were divided into <10.9 ng/ml, 10.9-13 ng/ml, and ≥13 ng/ml subgroups. In univariate analysis, there were no significant differences between mean weekly tacrolimus level subgroups and cumulative incidence of acute GVHD, chronic GVHD, relapse or NRM (Figure 1). In conclusion, following haplo-HCT with PTCy, there were no significant associations found between serum tacrolimus concentrations and the incidence of GVHD or other post-transplant outcomes. Given the lack of an obvious detrimental effect of lower tacrolimus levels, combined with the known toxicities associated with tacrolimus use (i.e. renal, neurologic, cardiovascular, diabetes mellitus), we speculate that lower target tacrolimus serum concentrations may be preferable following PTCy-based haplo-HCT.

Pharmacogenomic Impact of CYP2C19 Variation on Clopidogrel Therapy in Precision Cardiovascular Medicine.

Variability in response to antiplatelet therapy can be explained in part by pharmacogenomics, particularly of the CYP450 enzyme encoded by CYP2C19. Loss-of-function and gain-of-function variants help explain these interindividual differences. Individuals may carry multiple variants, with linkage disequilibrium noted among some alleles. In the current pharmacogenomics era, genomic variation in CYP2C19 has led to the definition of pharmacokinetic phenotypes for response to antiplatelet therapy, in particular, clopidogrel. Individuals may be classified as poor, intermediate, extensive, or ultrarapid metabolizers, based on whether they carry wild type or polymorphic CYP2C19 alleles. Variant alleles differentially impact platelet reactivity, concentration of plasma clopidogrel metabolites, and clinical outcomes. Interestingly, response to clopidogrel appears to be modulated by additional factors, such as sociodemographic characteristics, risk factors for ischemic heart disease, and drug-drug interactions. Furthermore, systems medicine studies suggest that a broader approach may be required to adequately assess, predict, preempt, and manage variation in antiplatelet response. Transcriptomics, epigenomics, exposomics, miRNAomics, proteomics, metabolomics, microbiomics, and mathematical, computational, and molecular modeling should be integrated with pharmacogenomics for enhanced prediction and individualized care. In this review of pharmacogenomic variation of CYP450, a systems medicine approach is described for tailoring antiplatelet therapy in clinical practice of precision cardiovascular medicine.

Inherited Variation in Vitamin D Genes and Type 1 Diabetes Predisposition.

The etiology and pathophysiology of type 1 diabetes remain largely elusive with no established concepts for a causal therapy. Efforts to clarify genetic susceptibility and screening for environmental factors have identified the vitamin D system as a contributory pathway that is potentially correctable. This review aims at compiling all genetic studies addressing the vitamin D system in type 1 diabetes. Herein, association studies with case control cohorts are presented as well as family investigations with transmission tests, meta-analyses and intervention trials. Additionally, rare examples of inborn errors of vitamin D metabolism manifesting with type 1 diabetes and their immune status are discussed. We find a majority of association studies confirming a predisposing role for vitamin D receptor (VDR) polymorphisms and those of the vitamin D metabolism, particularly the CYP27B1 gene encoding the main enzyme for vitamin D activation. Associations, however, are tenuous in relation to the ethnic background of the studied populations. Intervention trials identify the specific requirements of adequate vitamin D doses to achieve vitamin D sufficiency. Preliminary evidence suggests that doses may need to be individualized in order to achieve target effects due to pharmacogenomic variation.