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WASHINGTON -- An FDA advisory committee unanimously affirmed the safety and efficacy of a DNA stool test for colorectal cancer screening.

The Molecular and Clinical Genetics Panel also agreed by a 10-0 vote that the benefits of the Cologuard test outweigh any risks.

The panel's favorable review was based primarily on data from the pivotal DeeP-C trial, which showed the DNA test had significantly greater sensitivity for undiagnosed colon cancer, as compared with fecal immunochemical testing (FIT). The trial involved almost 10,000 patients scheduled for screening colonoscopy, which subsequently identified colorectal cancer in 65 patients and advanced precancerous lesions in 757.

Stool samples from each patient were analyzed by the DNA test and FIT. The DNA test had a 92.3% sensitivity for all 65 malignancies and 93.3% for the 60 cancers deemed clinically relevant (stages I-III). FIT evaluation of the specimens resulted in sensitivity values of 73.3% and 73.8%. The DNA test had a 42.4% specificity for detection of the precancerous lesions compared with 23.8% for FIT.

In contrast to conventional stool tests that identify evidence of occult bleeding, the Cologuard test is used to analyze stool specimens for the presence of DNA methylation and mutation markers, total DNA, and hemoglobin. The test takes advantage of the recognition that colorectal cancer arises from genetic and epigenetic changes that leave behind DNA evidence.

Manufacturer Exact Sciences is seeking FDA approval of the test as an adjunct to colonoscopy for average-risk patients ≥50.

The FDA is not bound by the panel's decision but usually follows the recommendations of its advisory committees.

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