This step by the FDA is to align itself with Japan and the European Union, by issuing its own definition for comment.

The basis of the document contains "definitions of key terms in the discipline of pharmacogenomics and pharmacogenetics, namely genomic biomarkers, pharmacogenomics, pharmacogenetics, and genomic data and sample coding categories," according to the report.

The reason for the guidance is the lack of consistently applied definitions of commonly used terminology which raises the potential for conflicting terms in documentation or inconsistent interpretation. The aim of the paper is to be able to fully integrate the international discipline of pharmacogenomics and pharmacogentics, as well as take into account the global drug development and approval processes.

The harmonised approach is an attempt by the FDA "to ensure that consistent definitions of terminology are being applied across all constituents of the International Conference on Harmonisation (ICH)".

The guideline also gives definitions and information regarding aspects covered by the definitions itself and notes that certain principles discussed in the document may also be applicable to related disciplines, such as proteomics and metabolomics.

From the guidance, the FDA gives definitions of genomic biomarker as a measurable DNA or RNA characteristic that is an indicator of normal biologic, pathogenic processes, a response to therapeutic or other interventions.

It also defines pharmacogenomics as the study of variations of DNA and RNA characteristics as related to drug response, while the discipline of pharmacogenetics is defined as the study of variations in DNA sequence as related to drug response.

There are also notes that offers harmonised definitions for the four general coding categories of biological samples used to generate data in pharmacogenomic and pharmacogenetic studies.

Pharmacogenomics has become more and more significant in the science of drug discovery. The discipline allows the identification of an individual's profile of drug response and predicts the best possible treatment option for that person. Genomic tests are also helping to identify cancers that have a better chance of responding to a particular medication or regimen.

The FDA also makes clear the guidance, titled E15 Definitions for Genomic Biomarkers, Pharmacogenomics, Pharmacogenetics, Genomic Data and Sample Coding Categories , is not definitive and as new scientific knowledge is discovered, then the FDA will expand and review the current guidance when necessary.