While blood tests can be used to detect some cancers, the FDA said a San Diego company has no proof its blood test works in patients who have not already been diagnosed with some form of the disease. Photo by Shawn Hempel/Shutterstock
WASHINGTON, Sept. 25 (UPI) -- A San Diego company selling an early cancer detection test was notified by the U.S. Food and Drug Administration it can find no evidence the test actually works, and is concerned it could prove to be harmful for some people.
Pathway Genomics debuted its CancerIntercept test in early September with claims it can detect cancer cell DNA in the blood, picking up mutations linked to as many as 10 different cancers. The goal is to catch cancer early in people who are "otherwise healthy" and not showing symptoms of the disease.
"Based on our review of your promotional materials and the research publication cited above, we
believe you are offering a high risk test that has not received adequate clinical validation and may
harm the public health," said FDA Deputy Director James L. Woods in a letter to the company.
CancerIntercept is billed by the company as a blood test looking for DNA fragments in the bloodstream and testing them for 96 genomic markers it says are found in several specific tumor types.
The direct-to-consumer test can be purchased through the Pathway Genomics website, with programs ranging from a one-time test to a quarterly "subscription" for people who want regular testing.
The company states, in several sections of its website, "the presence of one or more of these genomic markers in a patient's bloodstream may indicate that the patient has a previously undetected cancer. However, the test is not diagnostic, and thus, follow-up screening and clinical testing would be required to confirm the presence or absence of a specific cancer in the patient."
The FDA is concerned that people may seek treatment for tumors that do not require medical attention, or spend money and possibly seek out treatment they do not need at all -- in either case, unnecessary treatment for cancer is potentially harmful to people, the agency said.
CancerIntercept has not been approved by the FDA for use as a medical device, nor has it been subjected to peer review as most tests of its type would be. The company published a white paper on its website which outlines how the test works, supporting its efficacy with references to several clinical trials on detection of mutated DNA in the bloodstream.
Glenn Braunstein, Chief Medical Officer at Pathway Genomics, told The Verge Pathway had validated its tests with "hundreds" of patients, though those patients had well-defined, often advanced cancers.
In the letter from the FDA, Woods requests the company provide a timeline for meeting with the agency to review plans for future longitudinal studies on the product and specific details on studies that have been conducted before it was made available to consumers.