Biomarker

A biomarker is a defined characteristic that is measured as an indicator of a normal biological process, a disease-related process, or a biological response to an exposure or intervention, including treatment. Biomarkers may include molecular measurements, tissue characteristics, imaging findings, or physiological measurements such as blood pressure .^1,2

Biomarker is a broad category rather than a single type of test. Biomarkers may be used for different purposes, including detecting or confirming a disease, estimating the likelihood of future disease or progression, monitoring a condition, predicting whether a person is likely to respond to a particular treatment, measuring a biological response, or assessing safety .¹

A biomarker is not the same as a clinical outcome. A clinical outcome describes how a person feels, functions, or survives, whereas a biomarker measures an underlying biological characteristic. A laboratory or imaging measurement can therefore change in response to treatment without necessarily showing that the person feels better or has an improved health outcome .¹

A biomarker is also not automatically a surrogate endpoint. A surrogate endpoint is a biomarker used in a clinical trial as a substitute for a direct measure of clinical benefit and is expected to predict that benefit or harm based on supporting scientific evidence. Being measurable and biologically informative does not by itself establish that a biomarker can reliably substitute for a clinical outcome .¹