Hematopoietic progenitor cell mobilization is more robust in healthy African American compared to Caucasian donors and is not affected by the presence of sickle cell trait.

Transfusion. 2016 May;56(5):1058-1065

Authors: Panch SR, Yau YY, Fitzhugh CD, Hsieh MM, Tisdale JF, Leitman SF

Abstract
BACKGROUND: Granulocyte-colony-stimulating factor (G-CSF)-stimulated hematopoietic progenitor cells (HPCs) collected by apheresis have become the predominant graft source for HPC transplantation in adults. Among healthy allogeneic donors, demographic characteristics (age, sex, body mass index [BMI]) and baseline hematologic counts affect HPC mobilization, leading to variability in CD34+ apheresis yields. Racial differences in HPC mobilization are less well characterized.
STUDY DESIGN AND METHODS: We retrospectively analyzed data from 1096 consecutive G-CSF-stimulated leukapheresis procedures in healthy allogeneic African American (AA) or Caucasian donors.
RESULTS: In a multivariate analysis, after adjusting for age, sex, BMI, baseline platelet and mononuclear cell counts, and daily G-CSF dose, peak CD34+ cell mobilization was significantly higher among AAs (n = 215) than Caucasians (n = 881; 123 ± 87 × 10(6) cells/L vs. 75 ± 47 × 10(6) cells/L; p < 0.0001). A ceiling effect was observed with increasing G-CSF dose (10 µg/kg/day vs. 16 µg/kg/day) in AAs (123 ± 88 × 10(6) cells/L vs. 123 ± 87 × 10(6) cells/L) but not in Caucasians (74 ± 46 × 10(6) cells/L vs. 93 ± 53 × 10(6) cells/L; p < 0.001). In AA donors, the presence of sickle cell trait (SCT; n = 41) did not affect CD34+ mobilization (peak CD34+ 123 ± 91 × 10(6) cells/L vs. 107 ± 72 × 10(6) cells/L, HbAS vs. HbAA; p = 0.34). Adverse events were minimal and similar across race.
CONCLUSIONS: AAs demonstrated significantly better CD34 mobilization responses to G-CSF than Caucasians. This was independent of other demographic and hematologic variables. Studying race-associated pharmacogenomics in relation to G-CSF may improve dosing strategies. Adverse event profile and CD34 mobilization were similar in AA donors with and without SCT. Our findings suggest that it would be safe to include healthy AA donors with SCT in unrelated donor registries.

PMID: 27167356 [PubMed - as supplied by publisher]

Clinical Management of Head and Neck Cancer Cases: Role of Pharmacogenetics of CYP2 and GSTs.

Oncol Res Treat. 2016;39(4):221-6

Authors: Ruwali M, Dhawan A, Pant MC, Rahman Q, Khurana SM, Parmar D

Abstract
Head and neck squamous cell carcinoma (HNSCC) describes a wide range of malignant tumors which originate in the upper aerodigestive tract and have a multifactorial origin involving both genetic and lifestyle risk factors. The clinical management of head and neck cancer involves surgery, radiotherapy, and chemotherapy. With the advances in treatment strategies for HNSCC, newer targeted therapies are adding to the progress already achieved in the multimodality management of patients although the problems of differences in drug response and adverse drug reactions are still grave concerns. Cancer pharmacogenomics has fast emerged as a new and promising field for the early identification of genetic markers that can predict drug response or toxicity. This could greatly help in identifying genetic markers useful for the selection of optimal drugs, dose, and treatment duration on an individual basis resulting in improved drug efficacy and decreased toxicity. This review focuses on the various treatment modalities available for the clinical management of HNSCC followed by a description of the contribution of genetic variations to chemotherapeutic toxicity and response. Furthermore, studies addressing the association of genetic variants of drug-metabolizing enzymes with treatment response in head and neck cancer are also discussed.

PMID: 27160276 [PubMed - in process]

Use of Pharmacogenomics and Biomarkers in the Development of New Drugs for Alzheimer Disease in Japan.

Clin Ther. 2015 Aug;37(8):1627-31

Authors: Otsubo Y

Abstract
PURPOSE: Pharmacogenomics (PGx) and biomarkers have been utilized for improving the benefit/risk ratios of drugs and the efficiency of drug development. In the development of drugs for Alzheimer disease (AD), a number of clinical trials have failed to demonstrate clinical efficacy. To overcome this circumstance, the importance of using PGx/biomarkers for enhancing recruitment into clinical trials and for evaluating the efficacy of treatments has been increasingly recognized. In this article, the current status and examples of the use of PGx/biomarkers in Japan for drug development are explained.
METHODS: Guidelines, notifications, and administrative notices related to PGx/biomarkers were downloaded from the Web sites of the Pharmaceuticals and Medical Devices Agency (PMDA), the US Food and Drug Administration, and the European Medicines Agency. Data from clinical studies of AD drugs were obtained from the review reports of the PMDA. To analyze the current status of the use of PGx/biomarkers in Japan, "Issues to Consider in the Clinical Evaluation and Development of Drugs for Alzheimer's Disease (Interim Summary)" was also downloaded from PMDA Web site.
FINDINGS: There are 2 major measures of utilizing PGx/biomarkers for drug development: (1) biomarker qualification and (2) companion diagnostics. Recently, the PMDA issued a number of guidelines and notifications for their practical use. Although examples of qualified PGx/biomarkers and approved companion diagnostics are limited at present, it is expected that the use of PGx/biomarkers for the development of drugs against AD would increase.
IMPLICATIONS: For promoting the use of PGx/biomarkers in the development of drugs against AD, PGx/biomarkers should be qualified as early as possible. To that end, accumulating data on PGx/biomarkers from nonclinical or clinical trials and the concurrent development of reliable diagnostics in the early stage of the development process are indispensable. It is important to strengthen collaboration among the academia, industries, and regulatory agencies, followed by the establishment of an effective guideline in the area of AD.

PMID: 25963998 [PubMed - indexed for MEDLINE]

Integrating pharmacogenomics into clinical practice: promise vs reality.

Am J Med. 2016 May 4;

Authors: St Sauver JL, Bielinski SJ, Olson JE, Bell EJ, Mc Gree ME, Jacobson DJ, McCormick JB, Caraballo PJ, Takahashi PY, Roger VL, Rohrer Vitek CR

Abstract
BACKGROUND: Limited information is available regarding primary care clinicians' response to pharmacogenomic Clinical Decision Support (PGx-CDS) alerts integrated in the electronic health record.
METHODS: In February 2015, 159 clinicians in the Mayo Clinic primary care practice were sent e-mail surveys to understand their perspectives on the implementation and use of pharmacogenomic testing in their clinical practice. Surveys assessed how the clinicians felt about pharmacogenomics and whether they thought electronic PGx-CDS alerts were useful. Information was abstracted on the number of CDS alerts the clinicians received between October, 2013 and the date their survey was returned. CDS alerts were grouped into two categories: alert recommended caution using the prescription or the alert recommended an alternate prescription. Finally, data were abstracted regarding whether the clinician changed their prescription in response to the alert recommendation.
RESULTS: The survey response rate was 57% (n=90). Overall, 52% of the clinicians did not expect to use or did not know whether they would use pharmacogenomic information in their future prescribing practices. Additionally, 53% of the clinicians felt that the alerts were confusing, irritating, frustrating, or that it was difficult to find additional information. Finally, only 30% of the clinicians that received a CDS alert changed their prescription to an alternative medication.
CONCLUSIONS: Our results suggest a lack of clinician comfort with integration of pharmacogenomic data into primary care. Further efforts to refine PGx-CDS alerts to make them as useful and user-friendly as possible are needed to improve clinician satisfaction with these new tools.

PMID: 27155109 [PubMed - as supplied by publisher]

Personalized asthma therapy in blacks-the role of genetic ancestry.

J Allergy Clin Immunol. 2016 May;137(5):1370-1372

Authors: Dunn RM, Wechsler ME

PMID: 27155033 [PubMed - as supplied by publisher]

Toward precision medicine and health: Opportunities and challenges in allergic diseases.

J Allergy Clin Immunol. 2016 May;137(5):1289-1300

Authors: Galli SJ

Abstract
Precision medicine (also called personalized, stratified, or P4 medicine) can be defined as the tailoring of preventive measures and medical treatments to the characteristics of each patient to obtain the best clinical outcome for each person while ideally also enhancing the cost-effectiveness of such interventions for patients and society. Clearly, the best clinical outcome for allergic diseases is not to get them in the first place. To emphasize the importance of disease prevention, a critical component of precision medicine can be referred to as precision health, which is defined herein as the use of all available information pertaining to specific subjects (including family history, individual genetic and other biometric information, and exposures to risk factors for developing or exacerbating disease), as well as features of their environments, to sustain and enhance health and prevent the development of disease. In this article I will provide a personal perspective on how the precision health-precision medicine approach can be applied to the related goals of preventing the development of allergic disorders and providing the most effective diagnosis, disease monitoring, and care for those with these prevalent diseases. I will also mention some of the existing and potential challenges to achieving these ambitious goals.

PMID: 27155026 [PubMed - as supplied by publisher]

Predicting the Unpredictable: Drug-Induced QT Prolongation and Torsades de Pointes.

J Am Coll Cardiol. 2016 Apr 5;67(13):1639-50

Authors: Schwartz PJ, Woosley RL

Abstract
Drug-induced long QT syndrome (diLQTS) and congenital LQTS (cLQTS) share many features, and both syndromes can result in life-threatening torsades de pointes (TdP). Our understanding of their mechanistic and genetic similarities has led to their improved clinical management. However, our inability to prevent diLQTS has resulted in removal of many medicines from the market and from development. Genetic and clinical risk factors for diLQTS and TdP are well known and raise the possibility of TdP prevention. Clinical decision support systems (CDSS) can scan the patient's electronic health records for clinical risk factors predictive of diLQTS and warn when a drug that can cause TdP is prescribed. CDSS have reduced prescriptions of QT-prolonging drugs, but these relatively small changes lack the power to reduce TdP. The growing genetic evidence linking diLQTS to cLQTS suggests that prevention of TdP in the future may require inclusion of both genetic and clinical predictors into CDSS.

PMID: 27150690 [PubMed - in process]

Clinical Evaluation of Cisplatin Sensitivity of Germline Polymorphisms in Neoadjuvant Chemotherapy for Urothelial Cancer.

Clin Genitourin Cancer. 2016 Mar 10;

Authors: O'Donnell PH, Alanee S, Stratton KL, Garcia-Grossman IR, Cao H, Ostrovnaya I, Plimack ER, Manschreck C, Ganshert C, Smith ND, Steinberg GD, Vijai J, Offit K, Stadler WM, Bajorin DF

Abstract
BACKGROUND: Level 1 evidence has demonstrated increased overall survival with cisplatin-based neoadjuvant chemotherapy for patients with muscle-invasive urothelial cancer. Usage remains low, however, in part because neoadjuvant chemotherapy will not be effective for every patient. To identify the patients most likely to benefit, we evaluated germline pharmacogenomic markers for association with neoadjuvant chemotherapy sensitivity in 2 large cohorts of patients with urothelial cancer.
PATIENTS AND METHODS: Patients receiving neoadjuvant cisplatin-based chemotherapy for muscle-invasive urothelial cancer were eligible. Nine germline single nucleotide polymorphisms (SNPs) potentially conferring platinum sensitivity were tested for an association with a complete pathologic response to neoadjuvant chemotherapy (pT0) or elimination of muscle-invasive cancer (<pT2).
RESULTS: The data from 205 patients were analyzed-59 patients were included in the discovery set and 146 in an independent replication cohort-from 3 institutions. The stage pT0 (26%) and < pT2 (50%) rates were consistent across the discovery and replication populations. Using a multivariate recessive genetic model, rs244898 in RARS (odds ratio, 6.8; 95% confidence interval, 1.8-28.9; P = .006) and rs7937567 in GALNTL4 (odds ratio, 4.8; 95% confidence interval, 1.1-22.6; P = .04) were associated with pT0 in the discovery set. Despite these large effects, neither were associated with achievement of pT0 in the replication set. A third SNP, rs10964552, was associated with stage < pT2 in the discovery set but also failed to replicate.
CONCLUSION: Germline SNPs previously associated with platinum sensitivity were not associated with the neoadjuvant chemotherapy response in a large replication cohort of patients with urothelial cancer. These results emphasize the need for replication when evaluating pharmacogenomic markers and demonstrate that multi-institutional efforts are feasible and will be necessary to achieve advances in urothelial cancer pharmacogenomics.

PMID: 27150640 [PubMed - as supplied by publisher]

The Pharmacogenomics of Bipolar Disorder study (PGBD): identification of genes for lithium response in a prospective sample.

BMC Psychiatry. 2016;16(1):129

Authors: Oedegaard KJ, Alda M, Anand A, Andreassen OA, Balaraman Y, Berrettini WH, Bhattacharjee A, Brennand KJ, Burdick KE, Calabrese JR, Calkin CV, Claasen A, Coryell WH, Craig D, DeModena A, Frye M, Gage FH, Gao K, Garnham J, Gershon E, Jakobsen P, Leckband SG, McCarthy MJ, McInnis MG, Maihofer AX, Mertens J, Morken G, Nievergelt CM, Nurnberger J, Pham S, Schoeyen H, Shekhtman T, Shilling PD, Szelinger S, Tarwater B, Yao J, Zandi PP, Kelsoe JR

Abstract
BACKGROUND: Bipolar disorder is a serious and common psychiatric disorder characterized by manic and depressive mood switches and a relapsing and remitting course. The cornerstone of clinical management is stabilization and prophylaxis using mood-stabilizing medications to reduce both manic and depressive symptoms. Lithium remains the gold standard of treatment with the strongest data for both efficacy and suicide prevention. However, many patients do not respond to this medication, and clinically there is a great need for tools to aid the clinician in selecting the correct treatment. Large genome wide association studies (GWAS) investigating retrospectively the effect of lithium response are in the pipeline; however, few large prospective studies on genetic predictors to of lithium response have yet been conducted. The purpose of this project is to identify genes that are associated with lithium response in a large prospective cohort of bipolar patients and to better understand the mechanism of action of lithium and the variation in the genome that influences clinical response.
METHODS/DESIGN: This study is an 11-site prospective non-randomized open trial of lithium designed to ascertain a cohort of 700 subjects with bipolar I disorder who experience protocol-defined relapse prevention as a result of treatment with lithium monotherapy. All patients will be diagnosed using the Diagnostic Interview for Genetic Studies (DIGS) and will then enter a 2-year follow-up period on lithium monotherapy if and when they exhibit a score of 1 (normal, not ill), 2 (minimally ill) or 3 (mildly ill) on the Clinical Global Impressions of Severity Scale for Bipolar Disorder (CGI-S-BP Overall Bipolar Illness) for 4 of the 5 preceding weeks. Lithium will be titrated as clinically appropriate, not to exceed serum levels of 1.2 mEq/L. The sample will be evaluated longitudinally using a wide range of clinical scales, cognitive assessments and laboratory tests. On relapse, patients will be discontinued or crossed-over to treatment with valproic acid (VPA) or treatment as usual (TAU). Relapse is defined as a DSM-IV manic, major depressive or mixed episode or if the treating physician decides a change in medication is clinically necessary. The sample will be genotyped for GWAS. The outcome for lithium response will be analyzed as a time to event, where the event is defined as clinical relapse, using a Cox Proportional Hazards model. Positive single nucleotide polymorphisms (SNPs) from past genetic retrospective studies of lithium response, the Consortium on Lithium Genetics (ConLiGen), will be tested in this prospective study sample; a meta-analysis of these samples will then be performed. Finally, neurons will be derived from pluripotent stem cells from lithium responders and non-responders and tested in vivo for response to lithium by gene expression studies. SNPs in genes identified in these cellular studies will also be tested for association to response.
DISCUSSION: Lithium is an extraordinarily important therapeutic drug in the clinical management of patients suffering from bipolar disorder. However, a significant proportion of patients, 30-40 %, fail to respond, and there is currently no method to identify the good lithium responders before initiation of treatment. Converging evidence suggests that genetic factors play a strong role in the variation of response to lithium, but only a few genes have been tested and the samples have largely been retrospective or quite small. The current study will collect an entirely unique sample of 700 patients with bipolar disorder to be stabilized on lithium monotherapy and followed for up to 2 years. This study will produce useful information to improve the understanding of the mechanism of action of lithium and will add to the development of a method to predict individual response to lithium, thereby accelerating recovery and reducing suffering and cost.
TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01272531 Registered: January 6, 2011.

PMID: 27150464 [PubMed - in process]

Genome-wide association study identifies common variants associated with pharmacokinetics of psychotropic drugs.

J Psychopharmacol. 2015 Aug;29(8):884-91

Authors: Athanasiu L, Smorr LL, Tesli M, Røssberg JI, Sønderby IE, Spigset O, Djurovic S, Andreassen OA

Abstract
Individual variation in pharmacokinetics of psychotropic drugs, particularly metabolism, is an important factor to consider in pharmacological treatment in psychiatry. A large proportion of this variance is still not accounted for, but evidence so far suggests the involvement of genetic factors. We performed a genome-wide association study (GWAS) with concentration dose ratio (CDR) as sub-phenotype to assess metabolism rate of psychotropic drugs in a homogenous Norwegian sample of 1334 individuals diagnosed with a severe mental disorder. The GWAS revealed one genome-wide significant marker (rs16935279, p-value=3.95×10(-10), pperm=7.5×10(-4)) located in an intronic region of the lncRNA LOC100505718. Carriers of the minor allele have a lower metabolism rate of antiepileptic drugs compared to major allele carriers. In addition, several nominally significant associations between single nucleotide polymorphisms (SNPs) and CDR for antipsychotic, antidepressant and antiepileptic drugs were disclosed. We consider standardised CDR to be a useful measure of the metabolism rate of a drug. The present findings indicate that common gene variants could affect the metabolism of psychotropic drugs. This warrants further investigations into the functional mechanisms involved as it may lead to identification of predictive markers as well as novel drug targets.

PMID: 25944848 [PubMed - indexed for MEDLINE]

Pharmacological, Pharmacokinetic, and Pharmacogenomic Aspects of Functional Gastrointestinal Disorders.

Gastroenterology. 2016 Feb 18;

Authors: Camilleri M, Bueno L, Andresen V, De Ponti F, Choi MG, Lembo A

Abstract
This article reviews medications commonly used for the treatment of patients with functional gastrointestinal disorders. Specifically, we review the animal models that have been validated for the study of drug effects on sensation and motility; the preclinical pharmacology, pharmacokinetics, and toxicology usually required for introduction of new drugs; the biomarkers that are validated for studies of sensation and motility endpoints with experimental medications in humans; the pharmacogenomics applied to these medications and their relevance to the FGIDs; and the pharmacology of agents that are applied or have potential for the treatment of FGIDs, including psychopharmacologic drugs.

PMID: 27144621 [PubMed - as supplied by publisher]

Functional Gastrointestinal Disorders: History, Pathophysiology, Clinical Features and Rome IV.

Gastroenterology. 2016 Feb 19;

Authors: Drossman DA

Abstract
Functional gastrointestinal disorders (FGIDs), the most common diagnoses in gastroenterology are recognized by morphological and physiological abnormalities that often occur in combination including motility disturbance, visceral hypersensitivity, altered mucosal and immune function, altered gut microbiota and altered central nervous system processing. Research on these gut-brain interaction disorders is based on using specific diagnostic criteria. The Rome Foundation has played a pivotal role in creating diagnostic criteria thus operationalizing the dissemination of new knowledge in the field of FGIDs. Rome IV is a compendium of the knowledge accumulated since Rome III was published 10 years ago. It improves upon Rome III by: 1) updating the basic and clinical literature, 2) offering new information on gut microenvironment, gut-brain interactions, pharmacogenomics, biopsychosocial, gender and cross cultural understandings of FGIDs, 3) reduces the use of imprecise and occassionally stigmatizing terms when possible, 4) uses updated diagnostic algorithms, 5) incorporates information on the patient illness experience, and physiological subgroups or biomarkers that might lead to more targeted treatment. This introductory article sets the stage for the remaining 17 articles that follow and offers an historical overview of the FGIDs field, differentiates FGIDs from motility and structural disorders, discusses the changes from Rome III, reviews the Rome committee process, provides a biopsychosocial pathophysiological conceptualization of FGIDs, and offers an approach to patient care.

PMID: 27144617 [PubMed - as supplied by publisher]

Ligand cluster-based protein network and ePlatton, a multi-target ligand finder.

J Cheminform. 2016;8:23

Authors: Du Y, Shi T

Abstract
BACKGROUND: Small molecules are information carriers that make cells aware of external changes and couple internal metabolic and signalling pathway systems with each other. In some specific physiological status, natural or artificial molecules are used to interact with selective biological targets to activate or inhibit their functions to achieve expected biological and physiological output. Millions of years of evolution have optimized biological processes and pathways and now the endocrine and immune system cannot work properly without some key small molecules. In the past thousands of years, the human race has managed to find many medicines against diseases by trail-and-error experience. In the recent decades, with the deepening understanding of life and the progress of molecular biology, researchers spare no effort to design molecules targeting one or two key enzymes and receptors related to corresponding diseases. But recent studies in pharmacogenomics have shown that polypharmacology may be necessary for the effects of drugs, which challenge the paradigm, 'one drug, one target, one disease'. Nowadays, cheminformatics and structural biology can help us reasonably take advantage of the polypharmacology to design next-generation promiscuous drugs and drug combination therapies.
RESULTS: 234,591 protein-ligand interactions were extracted from ChEMBL. By the 2D structure similarity, 13,769 ligand emerged from 156,151 distinct ligands which were recognized by 1477 proteins. Ligand cluster- and sequence-based protein networks (LCBN, SBN) were constructed, compared and analysed. For assisting compound designing, exploring polypharmacology and finding possible drug combination, we integrated the pathway, disease, drug adverse reaction and the relationship of targets and ligand clusters into the web platform, ePlatton, which is available at http://www.megabionet.org/eplatton.
CONCLUSIONS: Although there were some disagreements between the LCBN and SBN, communities in both networks were largely the same with normalized mutual information at 0.9. The study of target and ligand cluster promiscuity underlying the LCBN showed that light ligand clusters were more promiscuous than the heavy one and that highly connected nodes tended to be protein kinases and involved in phosphorylation. ePlatton considerably reduced the redundancy of the ligand set of targets and made it easy to deduce the possible relationship between compounds and targets, pathways and side effects. ePlatton behaved reliably in validation experiments and also fast in virtual screening and information retrieval.Graphical abstractCluster exemplars and ePlatton's mechanism.

PMID: 27143991 [PubMed]

Potential utility of precision medicine for older adults with polypharmacy: a case series study.

Pharmgenomics Pers Med. 2016;9:31-45

Authors: Finkelstein J, Friedman C, Hripcsak G, Cabrera M

Abstract
Pharmacogenomic (PGx) testing has been increasingly used to optimize drug regimens; however, its potential in older adults with polypharmacy has not been systematically studied. In this hypothesis-generating study, we employed a case series design to explore potential utility of PGx testing in older adults with polypharmacy and to highlight barriers in implementing this methodology in routine clinical practice. Three patients with concurrent chronic heart and lung disease aged 74, 78, and 83 years and whose medication regimen comprised 26, 17, and 18 drugs, correspondingly, served as cases for this study. PGx testing identified major genetic polymorphisms in the first two cases. The first case was identified as "CYP3A4/CYP3A5 poor metabolizer", which affected metabolism of eleven prescribed drugs. The second case had "CYP2D6 rapid metabolizer" status affecting three prescribed medications, two of which were key drugs for managing this patient's chronic conditions. Both these patients also had VKORC1 allele *A, resulting in higher sensitivity to warfarin. All cases demonstrated a significant number of potential drug-drug interactions. Both patients with significant drug-gene interactions had a history of frequent hospitalizations (six and 23, respectively), whereas the person without impaired cytochrome P450 enzyme activity had only two acute episodes in the last 5 years, although he was older and had multiple comorbidities. Since all patients received guideline-concordant therapy from the same providers and were adherent to their drug regimen, we hypothesized that genetic polymorphism may represent an additional risk factor for higher hospitalization rates in older adults with polypharmacy. However, evidence to support or reject this hypothesis is yet to be established. Studies evaluating clinical impact of PGx testing in older adults with polypharmacy are warranted. For practical implementation of pharmacogenomics in routine clinical care, besides providing convincing evidence of its clinical effectiveness, multiple barriers must be addressed. Introduction of intelligent clinical decision support in electronic medical record systems is required to address complexities of simultaneous drug-gene and drug-drug interactions in older adults with polypharmacy. Physician training, clear clinical pathways, evidence-based guidelines, and patient education materials are necessary for unlocking full potential of pharmacogenomics into routine clinical care of older adults.

PMID: 27143951 [PubMed]

History repeats itself: the family medication history and pharmacogenomics.

Pharmacogenomics. 2016 May 4;

Authors: Smith TR, Kearney E, Hulick PJ, Kisor DF

Abstract
Related to many drug gene-product interactions, application of pharmacogenomics can lead to improved medication efficacy while decreasing or avoiding adverse drug reactions. However, utilizing pharmacogenomics without other information does not allow for optimal medication therapy. Currently, there is a lack of documentation of family medication history, in other words, inefficacy and adverse reactions across family members throughout generations. The family medication history can serve as an impetus for pharmacogenomic testing to explain lack of medication efficacy or an adverse drug reaction and pre-emptive testing can drive recognition and documentation of medication response in family members. We propose combining the family medication history via pedigree construction with pharmacogenomics to further optimize medication therapy. We encourage clinicians to combine family medication history with pharmacogenomics.

PMID: 27143300 [PubMed - as supplied by publisher]

[Pharmacogenomics study of 620 whole-exome sequencing: focusing on aspirin application].

Zhonghua Er Ke Za Zhi. 2016 May;54(5):332-6

Authors: Yang L, Lu YL, Wang HJ, Zhou WH

Abstract
OBJECTIVE: To investigate the allele frequencies of aspirin-response-related variants in different population.
METHOD: The allele frequencies of reported clinically significant aspirin-response-related variants were evaluated based on 620 whole exome sequencing (WES) data collected from 2013 to 2016 in Children's Hospital of Fudan University.Then the local allele frequencies were compared with 1 000 Genomes project database, and χ(2) test was used.
RESULT: Thirty-eight aspirin-response-related variants that had clinical significance had been detected in the 620 WES data.Ten (26%) of them were related with drug efficacy while 28 (74%) were related with toxicity or adverse drug reaction (ADR). These variants were distributed in 33 genes.There were 23 aspirin-related variants further analysised, and the frequency of 7 (rs1050891, rs6065, rs7862221, rs1065776, rs3818822, rs3775291 and rs1126643) had no significant difference compared with frequency of European and East Asian population of 1 000 Genome project (P>0.01 for both), 10 (rs2228079, rs1613662, rs4523, rs28360521, rs1131882, rs1047626, rs3856806, rs2768759, rs7572857 and rs1126510) of them had no significant difference compared with East Asian but were significantly different from European population, 1 (rs2075797) had no significant difference compared with frequency of European and different with frequency of East Asian, and 5 variants(rs10279545, rs730012, rs16851030, rs1353411, rs1800469)were different from frequency of both East Asian(0.019, 0.058, 0.167, 0.452, 0.340 vs. 0.100, 0.151, 0.396, 0.568, 0.453, χ(2)=21.798, 20.400, 67.543, 16.531, 15.807, P all<0.01) and European population(0.531, 0.312, 0.037, 0.179, 0.688, χ(2)=325.799, 92.877, 144.811, 156.471, 174.533, P all<0.01).
CONCLUSION: Most variants that have clinical significance in aspirin response are related with drug efficacy or drug toxicity or ADR, indicating the urgency of variants screen in clinical practice.Significant population-specificity is detected in local 620 WES data in aspirin-response-related variants.

PMID: 27143073 [PubMed - in process]

Invasive Aspergillus infection requiring lobectomy in a CYP2C19 rapid metabolizer with subtherapeutic voriconazole concentrations.

Pharmacogenomics. 2016 May 4;

Authors: Hicks JK, Gonzalez BE, Zembillas AS, Kusick K, Murthy S, Raja S, Gordon SM, Hanna R

Abstract
Individuals who carry the CYP2C19*17 gain-of-function allele have lower voriconazole exposure and are therefore at risk of failing therapy. Utilizing CYP2C19 genotype to optimize voriconazole dosage may be a cost-effective method of improving treatment outcomes. However, there are limited data describing what initial voriconazole dosage should be used in those with increased CYP2C19 metabolic capacity. Herein, we present a case report of a pediatric CYP2C19 rapid metabolizer (i.e., CYP2C19*1/*17) requiring a voriconazole dosage of 14 mg/kg twice daily (usual pediatric dosage ranges from 7 to 9 mg/kg twice daily). This case report supports the clinical utility of using CYP2C19 genotype to guide voriconazole dosing, and provides data for establishing an initial voriconazole dose in pediatric CYP2C19 rapid metabolizers.

PMID: 27143031 [PubMed - as supplied by publisher]

Differences in genetic variants in lopinavir disposition among HIV-infected Bantu Africans.

Pharmacogenomics. 2016 May 4;

Authors: Mpeta B, Kampira E, Castel S, Mpye KL, Soko ND, Wiesner L, Smith P, Skelton M, Lacerda M, Dandara C

Abstract
INTRODUCTION: Variability in lopinavir (LPV) plasma concentration among patients could be due to genetic polymorphisms. This study set to evaluate significance of variants in CYP3A4/5, SLCO1B1 and ABCC2 on LPV plasma concentration among African HIV-positive patients.
MATERIALS & METHODS: Eighty-six HIV-positive participants on ritonavir (LPV/r) were genetically characterized and LPV plasma concentration determined.
RESULTS & DISCUSSION: LPV plasma concentrations differed >188-fold (range 0.0206-38.6 µg/ml). Both CYP3A4*22 and SLCO1B1 rs4149056G (c.521C) were not observed in this cohort. CYP3A4*1B, CYP3A5*3, CYP3A5*6 and ABCC2 c.1249G>A which have been associated with LPV plasma concentration, showed no significant association.
CONCLUSION: These findings highlight the need to include African groups in genomics research to identify variants of pharmacogenomics significance.

PMID: 27142945 [PubMed - as supplied by publisher]

Pharmacogenomics in Pediatric Patients: Towards Personalized Medicine.

Paediatr Drugs. 2016 May 3;

Authors: Maagdenberg H, Vijverberg SJ, Bierings MB, Carleton BC, Arets HG, de Boer A, Maitland-van der Zee AH

Abstract
It is well known that drug responses differ among patients with regard to dose requirements, efficacy, and adverse drug reactions (ADRs). The differences in drug responses are partially explained by genetic variation. This paper highlights some examples of areas in which the different responses (dose, efficacy, and ADRs) are studied in children, including cancer (cisplatin), thrombosis (vitamin K antagonists), and asthma (long-acting β2 agonists). For childhood cancer, the replication of data is challenging due to a high heterogeneity in study populations, which is mostly due to all the different treatment protocols. For example, the replication cohorts of the association of variants in TPMT and COMT with cisplatin-induced ototoxicity gave conflicting results, possibly as a result of this heterogeneity. For the vitamin K antagonists, the evidence of the association between variants in VKORC1 and CYP2C9 and the dose is clear. Genetic dosing models have been developed, but the implementation is held back by the impossibility of conducting a randomized controlled trial with such a small and diverse population. For the long-acting β2 agonists, there is enough evidence for the association between variant ADRB2 Arg16 and treatment response to start clinical trials to assess clinical value and cost effectiveness of genotyping. However, further research is still needed to define the different asthma phenotypes to study associations in comparable cohorts. These examples show the challenges which are encountered in pediatric pharmacogenomic studies. They also display the importance of collaborations to obtain good quality evidence for the implementation of genetic testing in clinical practice to optimize and personalize treatment.

PMID: 27142473 [PubMed - as supplied by publisher]

2017 Mar 23 [updated 2025 Jun 23]. In: Pratt VM, Scott SA, Pirmohamed M, Esquivel B, Kattman BL, Malheiro AJ, editors. Medical Genetics Summaries [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2012–.

ABSTRACT

Amitriptyline is a tricyclic antidepressant used in the treatment of several psychiatric disorders, including major depression, obsessive-compulsive disorder, panic attacks, generalized anxiety disorder, post-traumatic stress disorder, and bulimia. Amitriptyline also has different off-label uses, including migraine prevention, neuropathic pain management, fibromyalgia, and enuresis (bedwetting) (1).

Tricyclic antidepressants (TCAs) primarily mediate their therapeutic effect by inhibiting the reuptake of both serotonin and norepinephrine, leaving more neurotransmitter in the synaptic cleft stimulating the neuron. Given that the tricyclics can also block different receptors (H1 histamine, α1-adrenergic, and muscarinic receptors), side effects are common. As such, selective serotonin reuptake inhibitors (SSRIs) have largely replaced the use of TCAs; however, TCAs still have an important use in specific types of depression and other conditions.

Amitriptyline is metabolized mainly via CYP2C19 and CYP2D6 pathways. Metabolism by CYP2C19 results in active metabolites, including nortriptyline, which is also a tricyclic antidepressant. Metabolism catalyzed by CYP2D6 results in the formation of the less active 10-hydroxy metabolite. Both the CYP2D6 and CYP2C19 genes are highly polymorphic, resulting in proteins with different enzyme activity or expression levels. Individuals who are CYP2D6 “ultrarapid metabolizers” (UM) have more than 2 normal function alleles (multiple copies), whereas CYP2C19 UM have 2 increased function alleles. Individuals who are CYP2D6 or CYP2C19 “poor metabolizers” (PM) have 2 no function alleles for CYP2D6 or CYP2C19.

The FDA-approved drug label for amitriptyline states that CYP2D6 PM have higher than expected plasma concentrations of tricyclic antidepressants when given usual doses. The FDA recommendations also include monitoring tricyclic antidepressant plasma levels whenever a tricyclic antidepressant is co-administered with another drug known to be an inhibitor of CYP2D6 (Table 1) (1).

The Dutch Pharmacogenetic Working Group (DPWG) of the Royal Dutch Association for the Advancement of Pharmacy (KNMP) have issued recommendations for altered dosing based on CYP2D6 metabolizer phenotype (Table 2) (2, 3). Individuals who are CYP2D6 UM may require up to 1.6 times the normal dose, though cardiac toxicity risk may indicate use of an antidepressant that is less dependent upon CYP2D6 metabolism, such as citalopram or sertraline. Dose reductions are recommended for CYP2D6 intermediate metabolizer (IM) individuals (75% of normal dose) and CYP2D6 PM individuals (60% of normal dose), along with monitoring for side effects and plasma drug levels. (3). The DPWG does not recommend any changes in dosing based on CYP2C19 metabolizer status, since the combined dose of amitriptyline and the active metabolite nortriptyline are not significantly impacted. (2)

In 2016, the Clinical Pharmacogenetics Implementation Consortium (CPIC) published dosing recommendations for tricyclic antidepressants based on CYP2C19 and CYP2D6 metabolizer status, either individually or in combination (Table 3, Table 4) (4). For CYP2D6 UM, CPIC recommends avoiding the use of a tricyclic due to the potential lack of efficacy, and to consider an alternative drug not metabolized by CYP2D6. If a TCA is still warranted, CPIC recommends considering titrating the TCA to a higher target dose (compared with CYP2D6 normal metabolizers, “NM”) and using therapeutic drug monitoring to guide dose adjustments. For CYP2D6 IM, CPIC recommends considering a 25% reduction of the starting dose, and for CYP2D6 PM, to avoid the use of tricyclics because of the potential for side effects. If a tricyclic is still warranted for CYP2D6 PM, CPIC recommends considering a 50% reduction of the starting dose while monitoring drug plasma concentrations to avoid side effects.

For CYP2C19 UM, CPIC recommends avoiding the use of tertiary amines (for example, amitriptyline) due to the potential for a sub-optimal response, and to consider an alternative drug not metabolized by CYP2C19, such as the secondary amines nortriptyline or desipramine. For CYP2C19 PMs, CPIC recommends avoiding tertiary amine use due to the potential for sub-optimal response, and to consider an alternative drug not metabolized by CYP2C19. If a tertiary amine is still warranted for CYP2C19 PMs, CPIC recommends considering a 50% reduction of the starting dose while monitoring drug plasma concentrations to avoid side effects (4). For gene-based dosing of TCAs for neuropathic pain, where the initial doses are lower, CPIC does not recommend dose modifications for PMs or IMs (either CYP2D6 or CYP2C19). For CYP2D6 UM individuals, CPIC optionally recommends considering an alternative medication due to a higher risk of therapeutic failure of TCAs for neuropathic pain (4).

PMID:28520380 | Bookshelf:NBK425165