Pharmacogenomics: what is next?

Oral Contraceptives and the Risk of Psychiatric Side Effects: A Review

Background

Oral contraceptives (OCs) are an essential medicine used by millions of people every day. Given the widespread usage of these medicines, even a small increase in psychiatric risk could be of clinical significance. Although mood-related side effects are a common reason for OC hesitancy and discontinuation, studies investigating psychiatric responses to OC treatment have had inconsistent results.

Summary

While OCs are beneficial for most users, there is evidence that a subgroup of users is susceptible to mood side effects. Randomized controlled trials have generally failed to find differences in mood symptoms between OC and placebo users, but observational studies comparing OC users to non-users have reported increases in symptoms of depression, anxiety, and eating disorders. Additionally, observational evidence suggests that OC users may be more likely to use prescription psychotropic medications and to attempt or die by suicide. However, responses to OC treatment are highly heterogeneous, and some users report mood improvement. A variety of factors may increase the likelihood of negative psychiatric side effects, including younger age, previous experience of side effects from OCs, and preexisting psychiatric disorders. Progestin-only pills may confer a higher psychiatric risk than combination pills.

Key Messages

Further research investigating factors that contribute to susceptibility to the mood-related side effects of OCs is clearly warranted. Genomic approaches may provide insight as to why some users experience side effects while others do not. Research elucidating who is most at risk and why will be essential to addressing prevalent concerns about the psychiatric risk of OCs.

Planning and Conducting a Pharmacogenetics Association Study

Pharmacogenetics (PGx) association studies are used to discover, replicate, and validate the association between an inherited genotype and a treatment outcome. The objective of this tutorial is to provide trainees and novice PGx researchers with an overview of the major decisions that need to be made when designing and conducting a PGx association study. The first critical decision is to determine whether the objective of the study is discovery, replication, or validation. Next, the researcher must identify a patient cohort that has all of the data necessary to conduct the intended analysis. Then, the investigator must select and define the treatment outcome, or phenotype, that will be analyzed. Next, the investigator must determine what genotyping approach and genetic data will be included in the analysis. Finally, the association between the genotype and phenotype is tested using some statistical analysis methodology. This tutorial is divided into five sections; each section describes commonly used approaches and provides suggestions and resources for designing and conducting a PGx association study. Successful PGx association studies are necessary to discover and validate associations between inherited genetic variation and treatment outcomes, which enable clinical translation to improve efficacy and reduce toxicity of treatment.

Translational paradigms in pharmacology and drug discovery

The translational sciences represent the core element in enabling and utilizing the output from the biomedical sciences and to improving drug discovery metrics by reducing the attrition rate as compounds move from preclinical research to clinical proof of concept. Key to understanding the basis of disease causality and to developing therapeutics is an ability to accurately diagnose the disease and to identify and develop safe and effective therapeutics for its treatment. The former requires validated biomarkers and the latter, qualified targets. Progress has been hampered by semantic issues, specifically those that define the end product, and by scientific issues that include data reliability, an overt reductionistic cultural focus and a lack of hierarchically integrated data gathering and systematic analysis. A necessary framework for these activities is represented by the discipline of pharmacology, efforts and training in which require recognition and revitalization.

V101L of human formyl peptide receptor 1 (FPR1) increases receptor affinity and augments the antagonism mediated by cyclosporins

Genetic variation plays a major role in drug response variability. CsA (cyclosporin A), a widely used immunosuppressive agent, is a specific antagonist for FPR1 (formyl peptide receptor 1), which is an important G-protein-coupled chemoattractant receptor in the innate immune system. In order to study the variable responses of cyclosporins to different FPR1 mutants, we investigated the distribution of human FPR1 haplotypes among 209 healthy Han Chinese subjects. The haplotype pattern in Han Chinese were characterized on the basis of five SNPs (single nucleotide polymorphisms), including rs5030878 (p.T11I), rs2070745 (p.V101L), rs5030880 (p.R190W), rs1042229 (p.N192K) and rs867228 (p.A346E). Receptor binding affinity of cyclosporins to FPR1 haplotypes was assessed using N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys–FITC in CHO-G_α16 cells stably transfected with cDNAs encoding the top 12 FPR1 haplotypes in the Han Chinese. Variants of FPR1 carrying a single amino acid substitution of leucine for valine at position 101 (p.Leu¹⁰¹) displayed significantly higher pK_i values for CsA and CsH (cyclosporin H), indicative of an improved receptor affinity. The polymorphism of FPR1 p.Leu¹⁰¹ also enhanced the inhibitory effects of cyclosporins on fMLF (N-formyl-methionyl-leucyl-phenylalanine)-induced activities, including calcium mobilization, cell chemotaxis and MAPK (mitogen-activated protein kinase) phosphorylation. These results point to a possible complication for clinical use of CsA in patients carrying the p.Leu¹⁰¹ allele of FPR1.

Pharmacogenomics and individualized medicine: translating science into practice

Research on genes and medications has advanced our understanding of the genetic basis of individual drug responses. The aim of pharmacogenomics is to develop strategies for individualizing therapy for patients, in order to optimize outcome through knowledge of the variability of the human genome and its influence on drug response. Pharmacogenomics research is translational in nature and ranges from discovery of genotype-phenotype relationships to clinical trials that can provide proof of clinical impact. Advances in pharmacogenomics offer significant potential for subsequent clinical application in individual patients; however, the translation of pharmacogenomics research findings into clinical practice has been slow. Key components to successful clinical implementation of pharmacogenomics will include consistent interpretation of pharmacogenomics test results, availability of clinical guidelines for prescribing on the basis of test results, and knowledge-based decision support systems.