23 July 2018 - The companion diagnostic plays a significant role in precision medicine.
As a predictive biomarker assay, often in vitro, it is linked to a drug’s indication, but can also be tied to multiple indications and drugs. Companion diagnostics provide information considered “necessary for the safe and effective use of a corresponding therapeutic.” Nearly 20 years ago, Dako’s HER2 FISH test was the first companion diagnostic to be approved by the FDA.
However, fewer than 5% of all in vitro diagnostics are companion diagnostics. And, most are used in oncology. Specifically, 30 companion diagnostics are officially designated by FDA as required for the use of 25 drugs in at least one indication. Twenty out of 25 of these are cancer drugs.