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Steve Halasey, chief editor, CLP.

At the beginning of December, FDA issued a draft guidance on the use of class labeling for companion diagnostics that could make it easier for labs and IVD manufacturers to work with the developers of cancer therapeutics.The proposed guidance addresses the situation that occurs when a companion diagnostic is tested only with a particular drug candidate, and then becomes linked to that drug to the exclusion of broader class labeling. As explained by FDA Commissioner Scott Gottlieb, MD:2

When an in vitro diagnostic test gets approved, it’s often based on the results of studies with one specific drug. As a consequence, the labeling of the test often reflects the use of that diagnostic in conjunction with just one drug. And, in turn, the drug can reflect the use of that medicine in conjunction with just one diagnostic test.

But this often isn’t the way medicine is practiced and the way patients receive care.

This sometimes narrow labeling that ties a drug to a specific diagnostic test happens even in cases where the diagnostic test is applicable to all drugs in a specific class of cancer medicines. This is a challenge given the way cancer care is emerging. Increasingly, new drugs are targeting specific molecular markers that drive the growth and spread of cancer. Sometimes, multiple drugs in a class of medicines target the same marker in a largely similar fashion.

As a remedy to the unintentionally restrictive labeling that can result from this situation, the draft guidance provides a framework and process for broadening the labeling of a companion diagnostic when supported by relevant scientific evidence. According to the agency, “if evidence is sufficient to conclude that the companion diagnostic is appropriate for use with a specific group or class of therapeutic products, the companion diagnostic’s intended use should name the specific group or class of therapeutic products, rather than specific products.” Gottlieb adds:

When it’s scientifically appropriate, the FDA supports developers of companion diagnostics to develop their products (or pursue broader labeling for approved companion diagnostics) in a way that results in broader labeling for their diagnostic products. This includes, for example, labeling that identifies a specific group or class of oncology therapeutic products. This new policy will help advance these goals, by making it more efficient to achieve class labeling for diagnostic tests used in oncology.

The 60-day public comment period for the guidance will last until February 5, 2019. Electronic comments can be submitted via


  1. Developing and Labeling In Vitro Companion Diagnostic Devices for a Specific Group or Class of Oncology Therapeutic Products: Guidance for Industry [draft guidance]. Silver Spring, Md: FDA, 2018. Available at: Accessed December 6, 2018.
  1. Statement from FDA Commissioner Scott Gottlieb, MD, on the FDA’s new effort for developing and class labeling of in vitro companion diagnostics for classes of oncology therapeutic products [online]. Silver Spring, Md: FDA, 2018. Available at: Accessed December 6, 2018.

Steve Halasey

Chief Editor, CLP

[email protected]

(626) 219-0199