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FDA clears test that detects patients’ risk of adverse reactions to irinotecan
The FDA cleared a new test for patients with colorectal cancer who are being considered for, or are currently taking, irinotecan (Camptosar, Genzyme).
The UGT1A1 molecular assay (Invader, Genzyme), developed by Third Wave Technologies Inc., detects variations in the UGT1A1 gene that have been associated with an increased risk for severe adverse reactions to irinotecan.
A prospective clinical study indicated that patients with one of these variations have greater than a ninefold risk of experiencing increased white blood cell counts from irinotecan than patients without a variation. Irinotecan labeling was recently updated to include dosing recommendations based on a patient’s UGT1A1 status.
“This [assay] will help doctors treat their colorectal cancer patients with the appropriate dose of Camptosar,” said Mara Aspinall, president of Genzyme Genetics. The company is beginning an education program to teach physicians about the risk of adverse events for certain patients.
The UGT1A1 test relies on the accuracy and scalability of Third Wave’s patented chemistry. In a study submitted to the FDA as part of the company’s clearance application, the UGT1A1 test was 100% accurate compared with DNA sequencing, the standard for genotype determination.
The American Cancer Society estimated that there would be about 104,950 new cases of colon cancer and 40,340 new cases of rectal cancer diagnosed in 2005. There are approximately 1 million survivors of colorectal cancer in the United States today, due largely to earlier detection and improved treatment options.