The U.S. Food and Drug Administration has approved a test that helps in assessing the risk of tumor recurrence and long-term survival for patients with relatively high-risk breast cancer. The TOP2A FISH pharmDx is the first approved device to test for the TOP2A (topoisomerase 2 alpha) gene in cancer patients.
The TOP2A gene plays a role in DNA replication. The TOP2A FISH pharmDx test uses fluorescently labeled DNA probes to detect or confirm gene or chromosome abnormalities, a technology known as fluorescent in situ hybridization (FISH).
The recurrence of cancer depends partly on certain genes whose activity may be altered by changes in the number of gene copies in the tumor. Changes in the TOP2A gene in breast cancer cells mean there is an increased likelihood that the tumor will recur or that long-term survival will be decreased.
"When used with other clinical information and laboratory tests, this test can provide health care professionals with additional insight on the likely clinical course for breast cancer patients," said Daniel Schultz, M.D., director of FDA's Center for Devices and Radiological Health. "It can also provide valuable information to assist health care providers and patients in better understanding the biology of breast cancer disease."
The test is suitable for breast cancer patients who are premenopausal or for whom tumor characteristics, such as tumor size or lymph node involvement, suggest a higher likelihood of tumor recurrence or decreased survival.
The FDA reviewed evidence that the test has been properly validated for its intended use.
The product was studied in Danish patients who were treated with chemotherapy after removal of a breast tumor. The test is conducted on a small piece of the removed tumor. The removed piece is stained with the FISH chemicals and studied under a microscope.
The company submitted data from a study using tumor samples and clinical data from 767 patients with high risk tumors at 21 centers in Denmark. These studies confirmed that the test was useful in estimating time to local or distant recurrence and overall survival in women who received certain chemotherapy regimens assisting in the treatment of the disease.
The product is manufactured by Dako Denmark A/S (Glostrup, Denmark).