Companion diagnostic
A companion diagnostic is a diagnostic test used as a companion to a therapeutic drug to determine its applicability to a specific person.
Companion diagnostics are co-developed with drugs to aid in selecting or excluding patient groups for treatment with that particular drug on the basis of their biological characteristics that determine responders and non-responders to the therapy.
Companion diagnostics are developed based on companion biomarkers, biomarkers that prospectively help predict likely response or severe toxicity.
