Herceptin was the first, the US Food and Drug Administration says at its consumer updates page. In 1998, the agency approved the drug to treat certain breast cancers, but there had to be a diagnostic to determine what type of breast cancer a patient had. Now, the agency adds, there are 19 cleared or approved companion diagnostic tests for a range of drugs to treat certain diseases and conditions.
Since companion diagnostics are necessarily linked to a certain drug, FDA says that the development of both the diagnostic and the drug should be done in concert with the agency's device center as well as its drug center, and that the process goes more smoothly when the test is developed before the drug enters clinical testing.
The agency yesterday announced that it is releasing the final guidance on companion diagnostics; the draft version was released in 2011.
"The companion diagnostics guidance is intended to help companies identify the need for these tests during the earliest stages of drug development and to plan for the development of a drug and a companion test at the same time," FDA says. "The ultimate goal of the final guidance is to stimulate early collaborations that will result in faster access to promising new treatments for patients living with serious and life-threatening diseases."