The accepted definition of 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 definition was derived from a 2016 partnership between the U.S. FDA and the National Institutes of Health (NIH). Biomarkers are not diagnostic tools—they do not assess how a patient feels, functions or survives—they are simply indicators. At present, seven categories of biomarkers provide various indications:
Monitoring: measured continuously to assess disease status.
Response: demonstrating a beneficial or harmful biological response.
Predictive: identifying individuals more likely to have a disease than similar individuals.
Safety: measuring the presence or extent of toxicity before or after exposure to a drug.