Medical Devices

Companion Diagnostics

A companion diagnostic is a medical device, often an in vitro device, which provides information that is essential for the safe and effective use of a corresponding drug or biological product. The test helps a health care professional determine whether a particular therapeutic product’s benefits to patients will outweigh any potential serious side effects or risks.

Companion diagnostics can:

  • identify patients who are most likely to benefit from a particular therapeutic product;
  • identify patients likely to be at increased risk for serious side effects as a result of treatment with a particular therapeutic product; or
  • monitor response to treatment with a particular therapeutic product for the purpose of adjusting treatment to achieve improved safety or effectiveness.

If the diagnostic test is inaccurate, then the treatment decision based on that test may not be optimal.

On July 31, 2014 the FDA issued “Guidance for Industry: In Vitro Companion Diagnostic Devices,” to help companies identify the need for companion diagnostics at an earlier stage in the drug development process and to plan for co-development of the drug and companion diagnostic test. The ultimate goal of the 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.

Page Last Updated: 07/31/2014
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