Biomarker

Key facts

Standard vocabulary

FDA-NIH BEST (Biomarkers, EndpointS, and other Tools) Resource

Qualification program

FDA Biomarker Qualification Program (CDER)

Legal basis for qualification

21st Century Cures Act of 2016

Measurement types

Molecular, histologic, radiographic or physiologic

What is a biomarker?

A biomarker is something that can be measured objectively and that tells you about biology. Blood glucose, tumor HER2 status, blood pressure and a variant in the BRCA1 gene are all biomarkers. A biomarker is distinct from a clinical outcome, which measures how a patient feels, functions or survives.

The FDA and the National Institutes of Health (NIH) publish a shared glossary called the BEST Resource so that drug developers, regulators and researchers use biomarker terms in the same way.

Types of biomarkers

The BEST Resource sorts biomarkers by what they are used for. One biomarker can fall into more than one category depending on context:

• Susceptibility or risk: indicates the chance of developing a disease.
• Diagnostic: detects or confirms a disease or a disease subtype.
• Monitoring: measured repeatedly to track disease status or exposure.
• Prognostic: indicates the likely course of disease regardless of treatment.
• Predictive: identifies who is more likely to respond to a specific treatment.
• Response: shows that a biological response has occurred after an intervention.
• Safety: indicates the likelihood, presence or extent of toxicity.

Why biomarkers matter

Biomarkers decide who gets enrolled in trials and who is eligible for a drug. Predictive biomarkers often appear in the Indications and Usage section of labeling, which ties drug demand to diagnostic testing volume. Some biomarkers serve as surrogate endpoints that can support approval before long-term outcome data exist.

For analysts, biomarker status is a join point between datasets: companion diagnostic approvals, drug labels, clinical trial eligibility criteria and variant databases such as ClinVar all refer to the same markers.

Qualified vs accepted biomarkers

FDA qualification through the Biomarker Qualification Program means a biomarker can be used for a stated context of use in any drug development program without being re-justified each time. Most biomarkers used in drug development are never formally qualified; they are accepted case by case within a single application.