Designing pharmacogenomic studies to be fit for purpose

Pharmacogenomics in the age of personalized medicine

The aim of personalized medicine is to offer the right treatment to the right person at the right dose, thus maximizing efficacy and minimizing toxicity for each individual patient. Pharmacogenomic approaches attempt to refine the aim of personalized medicine by utilizing an individual's germline and somatic DNA signatures to guide treatment. In this review, we highlight the current use of pharmacogenomic based biomarker information in drug labeling. We also present several case studies on the implementation of pharmacogenomic strategies in drug discovery and development. Lastly, we comment on current challenges to implementing pharmacogenomic based testing in the clinic.

Special populations and pharmacogenetic issues in tuberculosis drug development and clinical research

Special populations, including children and pregnant women, have been neglected in tuberculosis drug development. Patients in developing countries are inadequately represented in pharmacology research, and postmarketing pharmacovigilance activities tend to be rudimentary in these settings. There is an ethical imperative to generate evidence at an early stage to support optimal treatment in these populations and in populations with common comorbid conditions, such as diabetes and human immunodeficiency virus (HIV) infection. This article highlights the research needed to support equitable access to new antituberculosis regimens. Efficient and opportunistic pharmacokinetic study designs, typically using sparse sampling and population analysis methods, can facilitate optimal dose selection for children and pregnant women. Formulations suitable for children should be developed early and used in pharmacokinetic studies to guide dose selection. Drug-drug interactions between commonly coprescribed medications also need to be evaluated, and when these are significant, alternative approaches should be sought. A potent rifamycin-sparing regimen could revolutionize the treatment of adults and children requiring a protease inhibitor as part of antiretroviral treatment regimens for HIV infection. A sufficiently wide formulary of drugs should be developed for those with contraindications to the standard approaches. Because genetic variations may influence an individual's response to tuberculosis treatment, depending on the population being treated, it is important that samples be collected and stored for pharmacogenetic study in future clinical trials.

Pharmacogenomics in asthma therapy: where are we and where do we go?

The response to drug treatment in asthma is a complex trait and is markedly variable even in patients with apparently similar clinical features. Pharmaco-genomics, which is the study of variations of human genome characteristics as related to drug response, can play a role in asthma therapy. Both a traditional candidate-gene approach to conducting genetic association studies and genome-wide association studies have provided an increasing list of genes and variants associated with the three major classes of asthma medications: β2-agonists, inhaled corticosteroids, and leukotriene modifiers. Moreover, a recent integrative, systems-level approach has offered a promising opportunity to identify important pharmacogenomics loci in asthma treatment. However, we are still a long way away from making this discipline directly relevant to patients. The combination of network modeling, functional validation, and integrative omics technologies will likely be needed to move asthma pharmacogenomics closer to clinical relevance.

Pharmacogenetics: practices and opportunities for study design and data analysis

Pharmacogenetics (PGx) is increasingly used as a way to target treatment to patients who are most likely to benefit. To date, PGx has shown clinical significance across a few applications but widespread use has been limited by the need for further technical, methodological and practical advances and for educating clinical researchers on the value of PGx. Here, I describe the current scope of PGx research, including recent contributions to prospective study design. A case study is included to demonstrate the limitations of current practice and to describe some practical steps for improving the chances of identifying genetic effects. Additionally, I describe some opportunities for the integration and application of disparate data sources in exploratory PGx research.

Generating and weighing evidence in drug development and regulatory decision making: 5th US FDA-DIA workshop on pharmacogenomics

The 5th US FDA-Drug Industry Association (DIA) workshop in a series on pharmacogenomics entitled: 'Generating and Weighing Evidence in Drug Development and Regulatory Decision Making', contained four major topics (tracks): 'Learning from Labels and Label Changes: How to Build Pharmacogenomics into Drug Development Programs'; 'Enabling Pharmacogenomic Clinical Trials Through Sampling'; 'Designing Pharmacogenomics Studies to be Fit for Purpose'; and 'Co-Development of Drugs and Diagnostics'. The meeting was attended by approximately 200 professionals, primarily involved in drug development and healthcare delivery. Several critical elements drove the success of the meeting: it was recognized that the enriched conversation at this workshop between regulators and drug developers was driven with less inhibition than before and with a greater scientific focus on the issues. Multiple examples in the field and broader collective experience helped more in-depth thinking of the pros and cons of implementing pharmacogenetic/genetic approaches during drug development, in the current environment. It was also noted that this field is still developing and nascent as illustrated by the paucity of actual diagnostic-drug co-development examples. Furthermore, the complexities of conducting pharmacogenetic research in global drug-development programs was acknowledged as was the need for rigorous research designs and methodologies despite these challenges.