Abstract
The second international European Society of Pharmacogenomics and Theranostics (ESPT) conference was organized in Lisbon, Portugal, and attracted 250 participants from 37 different countries. The participants could listen to 50 oral presentations, participate in five lunch symposia and were able to view 83 posters and an exhibition. The first part of this Conference Scene will focus on the pharmacogenomics and biomarkers used in medical oncology, and in particular solid tumors. In addition, this article covers the two keynote conference introductory lectures by Ann K Daly and Magnus Ingelman-Sundberg. The second part of this article will discuss the clinical implementation of pharmacogenomic tests; the role of transports and pharmacogenomics; how stem cells and other new tools are helping the development of pharmacogenomics and drug discovery; and an update on the clinical translation of pharmacogenomics to personalized medicine. Part two of this Conference Scene will be featured in the next issue of Pharmacogenomics.
The meeting was organized by the European Society of Pharmacogenomics and Theranostics (ESPT) board members under the chairmanship of its president supported with the local help of CarolinoMonteiro, Sara Torgal, Luis Silva Santos and Pedro Gil, as well as help from the ESPT office in Nancy, France, Laurence Ben Rezig, the UMR INSERM U.1122 research team and Benjamin Richier for Com & Co, Marseille, France.
The meeting was held under the auspices of International and National Societies which were all represented at the opening ceremony : International Federation of Clincial Chemistry and Laboratory Medicine (IFCC); International Union of Basic and Clinical Pharmacology (IUPHAR); European Federation of Clinical Chemistry and Laboratory Medicine (EFLM); The Federation of European Pharmacological Societies (EPHAR); European Society of Predictive Medicine (EUSPM); European Society for Biopreservation and Biobanking (ESBB); Portuguese Society of Pharmacology (SPF); Portuguese Society of Clinical Chemistry (SPQC); Portuguese Association of Students of Pharmacy (APEF); Spanish Society of Clinical Biochemistry and Molecular Pathology (SEQC); Spanish Society of Pharmacogenetics and Pharmacogenomics (SEFF); Spanish Society of Clinical Pharmacology (SEFC); Ordemdos Farmacêuticos (OF); Ordemdos Médicos (OM); Ordemdos Biólogos (OB).
The 3 days of meeting were subdivided in five lecture sessions:
▪ Pharmacogenomics and biomarkers in medical oncology: across the spectrum of solid tumors
▪ Clinical implementation of pharmacogenomics tests
▪ Transporters and pharmacogenomics
▪ Stem cells and other new tools for pharmacogenomics and drug discovery
▪ From system pharmacogenomics to personalized medicine
Five lunch symposia were also organized, as outlined below:
Randox
▪ Application of Biochip array technology for multiplex pharmacogenomics profiling, John Lamont
▪ The ‘Rheumastrat‘ biochip array; a multiplex SNP array for the stratification of therapy response in rheumatoid arthritis patients, Cathy McGeough
▪ The importance of VEGF in pharmacogenomic, Sophie Visvikis-Siest
▪ Potential to enhance colorectal cancer patient pathways through multiplex mutational profiling of KRAS, BRAF and PIK3CA genes, Helena Murray
Affymetrix
▪ Right drug, right patient, right dose, right time: The translation of pharmacogenetics into practice, Johanne McGregor
▪ Development of pharmacogenetic guidelines by the Dutch pharmacogenetics Working Group, Jesse J Swen
Life Technologies
▪ Your new research companion for Pharmacogenomics, Dominique Dewolf
▪ Design and validation of a SNP Panel in the QuantStudio™ OpenArray® Platform for Pharmacogenetic Research in Psychiatry, Miquel Tuson
▪ Ion-Torrent Next-Generation Sequencing for cancer mutation detection, Marivi Carretero
Qiagen – Applications of molecular screening
▪ A new IDH1/2 PCR assay for one-step detection of 12 IDH1 and IDH2 mutations in glioma, Hélène Peyro-Saint-Paul
▪ From sample to insight: bringing next-generation sequencing into clinical routine, Fabienne Hermitte
Agilent
▪ Next Generation Thinking – Integrated Genomics Solutions for Human Disease Research, Didier Goidin
Advanced training course
An Advanced Training Course with six speakers was organized the day before the main meeting: attendees also participate in the full meeting. Two introductory lectures opened the meeting, as described below.
Opening lectures
The first opening lecture was presented by Ann K Daly (Newcastle University, Newcastle, UK) with a lecture entitled ‘Recent Progress in Molecular Methods for Pharmacogenomics Studies‘. She presented three groups of pharmacogenomics applications, and compared genotyping and phenotyping for TPMT deficiency screening in treating patients for cancer and for CYP2C19 genotyping by a new point-of-care test for clopidogrel. Furthermore, she focused on warfarin pharmacogenomics, with the genome-wide association studies (GWAS) confirming data from candidate gene studies. A third topic was the involvement of HLA in idiosyncratic adverse drug reactions – that is, for flucloxacilline and amoxicillin. Concluding, Prof. Daly addressed new technologies, with the exome analysis seeming to identify new genes involved in adverse reactions.
Magnus Ingelman-Sundberg (Karolinska Institute, Stockholm, Sweden) presented the second lecture on ‘Pharmacogenomics of Endogenous Metabolism and its Implication for Behavior, Psychopathology and Treatment‘. After an introduction on the different GWAS looking for drug-metabolizing enzymes (DME), he discussed epigenetic data on hepatic DME genes with DNA methylation landscapes. Only a small part of DME genes show differences in methylation, including promoter regions. The methylated amplicons are differently regulated and are at the origin of expression variations between fetal liver and adult liver, that is, for GST, ABC genes. Hydroxymethylations (5-hydroxymethylcytosine) are in the enhancers and in CpG islands and not in the intergenic regions. Interestingly, in the liver 30–40% of cytosine modifications are 5hmC, indicating that previous work using the bisulfite technique has missed the important distinction between the more inhibitory 5mC and the more activatory 5hmC in the liver. He showed how 3D cultures of hepatocytes are a better tool for studying drug-induced liver toxicity, with more expression of relevant genes.
However, the highlight of the presentation was the discussion of CYP2C19 expression in the brain of mice and the effect of differential expression on the formation of the hippocampus. The mouse model is bringing new hypotheses on the potential role of CYP2C19 in brain function. CYP2C19 was expressed in the fetal but not adult brain. The differences in the transgenic model compared with the adult type were that the hippocampus area decreased, whereas the behavior tests showed a greater stress, an increased activity and an increased anxiety. The molecular background seems to be a decreased number of immature neurons in the dentate gyrus. This demonstrates that CYP2C19 could have a future potential role in brain disorders.
First session: pharmacogenomics & biomarkers in medical oncology: across the spectrum of solid tumors
▪ Bohuslav Melichar (Olomouc, Czech Republic) & Rui Medeiros (Porto, Portugal)
Despite the advent of new therapies, cancer currently represents one of the most important public health problems. After decades of indiscriminate use of anticancer drugs, more personalized approaches have emerged that made the concept of targeting the right agent for the right patient a reality. Across the spectrum of different primary tumors, various strategies have evolved to predict the pharmacokinetics, toxicity and, most importantly, the activity of anticancer drugs. Although the topics discussed represent only a fraction of problems under active research, the spectrum of tumors and therapeutic approaches illustrates the possibility of universal utilization of pharmacogenetic and theranostic approaches in the pharmacotherapy of cancer.
Nucleoside analogues, including 5-fluorouracil or gemcitabine, represent the backbone of chemotherapy regimens used in the treatment of gastrointestinal malignancies. Although these agents are, in general, well tolerated, the instances of serious, sometimes even fatal complications represent a major issue in the management of patients with gastrointestinal cancers. The topic of predicting toxicity of 5-fluorouracil and gemcitabine and, most importantly, integrating the predictive testing into routine practice was introduced by J Ciccolini (Aix-Marseille University & CHU Timone, Marseille, France). Genetic polymorphisms of dihydropyrimidine dehydrogenase are responsible for more than 50% of cases of severe toxicity associated with the administration of fluoropyrimidines. In addition, there are clinical data demonstrating that the 5-fluorouracil dose adjustment based on dihydropyrimidine dehydrogenase activity results in reduction of toxicity and improved treatment delivery. However, the lack of standardization of the methods to assess dihydropyrimidine dehydrogenase activity has so far represented an obstacle in the widespread adoption of dihydropyrimidine dehydrogenase testing for all patients scheduled to be treated with fluoropyrimidine-based chemotherapy. Cytidine deaminase is the key enzyme responsible for gemcitabine elimination. Because of the unclear relationship between the genotype and phenotype, the measurement of enzymatic activity is used to assess cytidine deaminase status. It has been demonstrated that decreased cytidine deaminase activity is associated with toxicity in patients treated with gemcitabine. Interestingly, high cytidine deaminase activity is associated with toxicity of another anticancer drug, capecitabine, a fluoropyrimidine. Toxicity after administration of capecitabine has also been described in association with the polymorphism of the thymidylate synthase gene. The routine assessment of the genetic polymorphisms or activities of these enzymes would not only prevent most cases of severe toxicity, but would also result in better delivery of anticancer drugs using individually tailored dosing.
Lung cancer is the leading cause of cancer mortality in the EU. The targeted therapeutic approaches that emerged in patients affected with this tumor during the past decade have stressed the importance of predictive biomarkers. This topic was addressed by G Berchem (Luxembourg Hospital Center, Luxembourg). Mutations of the EGFR gene predict the sensitivity of tumor to the low-molecular-weight EGFR tyrosine kinase inhibitors gefinitib and erlotinib. Moreover, another targeted approach in non-small-cell lung cancer involves anaplastic lymphoma kinase inhibition using crizotinib. The identification of molecular biomarkers is crucial as these drugs are active only in a minority of patients, and indiscriminate use of these novel agents would not only mean wasting of resources, but, more importantly, wasting precious time for effective therapy while using an agent that cannot work in a given patient.
The association between glutathione S-transferase gene polymorphism, busulfan metabolism and therapeutic outcome was discussed by M Ansari (CANSEARCH, Foundation for Children‘s Cancer, Geneva, Switzerland). Busulfan is the principal component of myeloablative regimens used in pediatric patients undergoing hematopoietic stem cell transplantation. Marked interindividual differences in busulfan pharmacokinetics may result in complications or treatment failure. Glutathione S-transferase is the principal enzyme responsible for busulfan elimination. It has been demonstrated that polymorphisms in the genes coding for glutathione S-transferase isoforms may partly explain the pharmacokinetic variability after intravenous administration of busulfan.
Colorectal carcinoma is one of the most common tumors and one of the leading causes of mortality in the EU. Despite efforts aimed at screening, the tumors are still diagnosed late. In addition, distant metastases subsequently manifest in a significant proportion of patients treated for early colorectal carcinoma. Despite the advent of targeted agents, cure is not possible in most cases of metastatic colorectal carcinoma. Cytotoxic chemotherapy remains the main component of systemic therapy. However, in contrast to other tumors, only a limited spectrum of cytotoxic drugs has reproducible activity in colorectal carcinoma. Historically, many research efforts have been aimed at compensating the limited number of active agents available in colorectal carcinoma by identifying elaborate regimens of utilization of these drugs. The benefits of hepatic arterial infusion, prolonged continuous infusion, or administration using chronomodulated schemes have been explored. D Paez (Santa Creu i Sant Pau Hospital, Barcelona, Spain) presented another approach using pharmacodynamic parameters in defining the dose of irinotecan in patients with metastatic colorectal carcinoma. Gastrointestinal toxicity (diarrhea) is the dose-limiting toxicity of irinotecan. In clinical practice, gastrointestinal toxicity may become life-threatening when associated with myelosuppression. Uridine diphosphate glucuronosyltransferase is the key enzyme responsible for elimination of 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of irinotecan. Genetic polymorphism of uridine diphosphate glucuronosyltransferase is reflected in marked interindividual differences of pharmacokinetics of SN-38 that also result in marked differences in toxicity. A prospective study has demonstrated that, in fact, the majority of subjects receiving irinotecan are significantly under-dosed, with the maximum tolerated dose being more than twice higher than the currently recommended dose, while in a minority of patients with phenotype that results in slower SN-38 metabolism the maximum tolerated dose is 30% lower than currently recommended. Moreover, higher irinotecan dose resulted in a significantly increased response rate and in prolongation of time to disease progression. Given the limited number of active agents available for the management of metastatic colorectal carcinoma, pharmacogenetic-based dosing may be regarded as a major step forward.
Pancreatic cancer remains the tumor with probably the most dismal prognosis of all malignancies. The disease is diagnosed late in most cases and sensitivity to systemic chemotherapy is limited. In fact the administration of currently available agents results only in a modest prolongation of overall survival, while being associated with significant, sometimes even life-threatening, toxicity. One of the reasons behind the limited sensitivity or even primary resistance of pancreatic carcinoma is the lack of expression of molecules mediating transport of the drug into the cell, or even the presence of transporters mediating the elimination of cytotoxic drugs or metabolites from the cytoplasm. The research on the effect of the presence of membrane transport molecules on the outcome of systemic treatment in patients with pancreatic carcinoma was summarized by B Mohelnikova-Duchonova (National Institute of Public Health, Praha, Czech Republic). It was demonstrated that the expression of ABC efflux transporters is increased and the expression of SLC transporters responsible for anticancer drug uptake is decreased in pancreatic cancer cells. Moreover, a significant association of SLC polymorphism with the overall survival was evident even in patient cohorts of limited size. Still, the research on these biomarkers that might predict pancreatic cancer chemosensitivity is at the very beginning, and in many instances the data are inconclusive, or conflicting results have even been reported by different authors.
The incidence of prostate cancer increases with age, and with aging of the population in the EU, prostate cancer is becoming a major public health problem. The topic of pharmacogenomics of castration-resistant prostate cancer was introduced by R Medeiros (Instituto Portugues de Oncologia, Porto, Portugal). Hormonal castration therapy (HCT) has been the standard of care in advanced and metastatic prostate cancer. The proposed rationale is that androgen deprivation inhibits the proliferation of prostate tumoral cells leading to tumor regression. However, although patients benefit from the treatment, the inevitable progression will occur with a decrease in the mean overall survival. The establishment of new biomarkers to predict response to this treatment remains to be determined, and the molecular mechanisms involved in acquisition of resistance to hormonal castration have not been clarified. Genetic polymorphisms associated with prostate cancer aggressiveness may also be implicated in the process of resistance to hormonal castration. Several lines of evidence indicate that molecules implicated in androgen pathways are liable to prostate cancer refractoriness to hormonal castration. Therefore, functional polymorphisms in genes related to this pathway may impact androgen bioavailability and help predict resistance to hormonal castration. Previous studies on the androgen pathway found association between CYP19A1, HSD3B1 and HSD17B4 genetic variants with the efficacy of HCT. Recently, multivariate analysis showed an increased risk of developing resistance to hormonal castration under the influence of SHBG genetic polymorphism. Furthermore, to address the complexity of these mechanisms, with the involvement of several probably interconnected pathways, it has been also reported that patients under HCT and carrying the HIF1A +1772 T-allele (rs11549465) present an increased risk for developing distant metastasis and an independent sixfold increased risk for resistance to HCT. The acquisition of castration-resistant phenotype is also associated with the activation of signaling pathways mediated by growth factors. TGFβ1 and its receptors have an important role in tumor progression, being the pro-apoptotic function modulated by the expression of TGFBR2. Within this line of research, it was found that TGFBR2-875GG homozygous patients present lower expression levels of TGFBR2 mRNA. Furthermore, in these individuals, carriers of the GG genotype, a link was found with higher Gleason grade and the increased risk of an early relapse after HCT. The TGFBR2-875G>A contribution to an early relapse in HCT patients, due to changes in mRNA expression, supports the involvement of TGFβ1 pathway in CRPC.
We can conclude that there is now an increasing body of evidence to support the use of pharmacogenomic approaches in the management of patients with a wide range of malignant disorders, not only to identify patients at increased risk of side effects, but also to guide the selection of the right drug for the right patient.
After this session, four oral presentations described other pharmacogenomics tools and recommendations. Charles Cantor (Sequenom, San Diego, USA), in his presentation entitled ‘Personalized Pharmacogenetics‘, suggested the use of tumor-specific genetic and epigenetic biomarkers detectable in tissue biopsies and in plasma for the monitoring of cancer therapy and patient management. The use of DNA Mass Spectrometry was proposed as a sensitive, quantitative and cost-effective way of mutation identification and its application in the Sequenom Absorption, Distribution, Metabolism and Excretion (ADME) Pharmacogenetics Panel Genes was presented (it includes 192 assays in 36 genes). Furthermore, a novel approach for multiplex ultrasensitive detection assay of somatic mutations in tumor samples has been developed and it presents a high analytical sensitivity (93%) and specificity (99%). A preliminary panel of somatic mutations is already constructed. The use of OncoCarta™ panel was also proposed for the assessment of the tumor clonality, where tumor-specific mutations are described. Finally, an interesting application of plasma DNA sequencing for therapy monitoring of cancer patients was presented. Malin Lindqvist Appell (Linköping University, Sweden), in the presentation entitled ‘Formation of a TPMT Nomenclature Committee – Bringing Order and Consensus Around Known and Novel TPMT Sequence Variants‘, discussed the problem of nonstandard clinical nomenclature for the genetic variants of the DME TPMT. The related gene is polymorphic and many sequence variants cause a decreased enzyme activity. As TPMT metabolizes the thiopurines 6-mercaptopurine, 6-thioguanine and azathioprine, the pretreatment determination of TPMT genetic status is suggested in many countries for the dose optimization before the initiation of thiopurine treatment. To avoid the confusion, a panel of 16 scientists around the world has created a nomenclature committee to define nomenclature and numbering of novel variants for the TPMT gene. The available website was described during this talk. The other two presentations presented the results of research studies that could have some clinical implementation on pharmacogenomics. Maria Stathopoulou (University of Lorraine, Nancy, France) presented a work entitled ‘Synergy Between Clopidogrel and Calcium-Channel Blockers for Blood Pressure Regulation Possibly Involves CYP2C19 Polymorphism‘. In this study, a synergistic effect between clopidogrel and calcium-channel blockers on blood pressure levels was observed in a sample of 2322 patients with acute myocardial infarction or unstable angina. This synergy was protective as it was associated with significantly lower levels of diastolic blood pressure. Additionally, the effect of the CYP2C19*2 polymorphism (rs4244285), which is a known determinant of clopidogrel‘s activity, was also assessed in terms of blood pressure level modification in a healthy population of 2155 individuals. A significant lowering effect for both systolic and diastolic blood pressure was revealed for the carriers of the minor allele, thus indicating a possible link between clopidogrel and blood pressure regulation. Finally, Nádia Marques Grilo (NOVA University of Lisbon, Portugal), in her presentation ‘Relevance of CYP2C19 Genotypes in Neviperapine Biotransformation‘, described a study on the assessment of the influence of CYP2C19 variant alleles (*2 and *17) on nevirapine (NVP)/12-OH-NVP metabolic ratio. The NVP biotransformation was studied in a population of 51 HIV-infected patients who were in NVP-based combined antiretroviral therapy (400 mg) for more than 1 month. Significant differences were observed only between NVP concentrations and carriers of the CYP2C19*2, thus suggesting that this variant plays a role in NVP biotransformation and the underlying severe idiosyncratic hepatotoxicity and cutaneous hypersensitivity that have been observed with this treatment.
Full more information and a full list of ESPT conferences, please visit www.esptnet.eu.
Financial & competing interests disclosure
The second ESPT conference couldn‘t have been organized without the help of our sponsors, in particular our gold sponsors (Bühlmann Laboratories, Randox and Roche), our silver sponsors (Agilent Technologies, Life Technologies, Affymetrix, Qiagen and Roche Diagnostics), our bronze sponsors (Luminex, Teva and Sequenom) and other support we obtained from DNA Genotek, Future Medicine, De Gruyter and Genomic Industry. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
No writing assistance was utilized in the production of this manuscript.