What is a biomarker and what is biomarker analysis?
Biomarker is a term found within medicine, physiology, clinical analysis, pharmaceutical development and clinical diagnostics. In this post, we will look at biomarkers and what we mean when discussing biomarker analysis.
What is a biomarker?
So ‘what is a biomarker?’ According to the FDA / NIH working group, a biomarker is ‘a defined characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions.’
This means that biomarkers can differ depending on the application. So blood pressure and lung function are classified as biomarkers for physiological measurements. In the clinical laboratory, liver function tests and physiological electrolyte levels are examples of biomarkers. In biopharmaceutical development, cytokines, growth factors, neurological peptides, and gene expression are biomarkers or potential biomarkers.
To be recognized as a biomarker by regulatory agencies, biomarkers need to be ‘qualified’ as such. This is an activity that is determined by substantial clinical and pharmaceutical collaboration to confirm and demonstrate the role of the biomarker and that it fulfils the criteria above.
Many biomarkers have been well established for decades, and methods for their measurement are routine within the clinical setting, such as for hormones and inflammatory mediators, amongst several others.
Medical and pharmaceutical research is constantly evolving and deepening the understanding of many disease pathologies that have thus far eluded full definition. The identification of ‘new’ biomarkers greatly assists these endeavours and, importantly, the ability to quantify these biomarkers at meaningful levels that eventually can be used predictively, diagnostically and prognostically in relation to disease.
What is Biomarker Analysis?
As can be seen above, much effort in drug discovery and clinical development is conducted with the accompanying analysis of a multitude of potential biomarkers and confirmation of their usefulness is part of the process. The intended use of the data from such analyses is important in determining the level of assay development and validation required. It is worthy of note the distinction between biomarker qualification and qualification/validation of biomarker analysis. Biomarker qualification is described above. For biomarker analysis validation, this refers to the methods used to quantify the biomarkers. A full, comprehensive development and validation of a method for every exploratory biomarker would be impractical. It is important, therefore, to determine what is referred to as the ‘context of use’.
In short, if the analysis aims to be fact-finding and purely exploratory, an off-the-shelf kit may be used without in-depth validation. For exploratory biomarkers, a multiplex approach is a popular choice, where basic information can be derived on anything between 2 to 30 analytes at the same time in a cost and time -effective manner. If, however, the biomarker is established or intended to be used in decision-making steps in the progress of a clinical study, a full validation would be expected. There are a number of diverse analytical approaches that can be taken, including immunoassay, flow cytometry and LC-MS/MS, to name but a few.
Such is the importance of biomarker research a topical example of the utility of biomarkers made it to mainstream US news just last month, where the identification of a specific biomarker enabled lifesaving treatment for a young lung cancer patient due to the ability to treat the disease in a targeted manner.
In recent years attention to neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease has accelerated due to the increasing prevalence and previously intractable nature of these diseases. Although cures are still some way away, advances have been made in no small measure due to the identification of specific biomarkers.
Another identified plight of the modern age is the impact of mental health diseases, and within this field, potential biomarkers are under investigation.
In the broader outlook, the discovery of biomarkers and ascertaining their role in pathological conditions cannot be overestimated. The medical, technical and analytical advances are impressive and increasingly useful in the diagnosis of disease in its early stages and subsequent treatments.