FDA Medical Bulletin * June 1996 * Volume 26 Number 2

FDA APPROVES FIRST BLOOD TEST
FOR BREAST CANCER RECURRENCE

The test measures CA 27.29, a tumor marker similar to CA 15-3 antigen, found in the blood of patients with breast cancer and certain other types of cancer. As breast cancer progresses, the level of CA 27.29 antigen in the blood rises. In clinical studies, the new test accurately detected the breast cancer antigen in 58 percent of women who had a recurrence.

Currently, recurrence is monitored through such procedures as mammography, magnetic resonance imaging, and x-ray.

The new test is not intended as the sole basis for a diagnosis of cancer, which can be made only after the results are verified by other procedures, but rather gives doctors an additional tool to help detect the recurrence of breast cancer in the earliest stages.

A blood sample is tested using the Truquant BR Radioimmunoassay (RIA) test kit made by Biomira Diagnostics, Inc., of Rexdale, Ontario, and the results can be analyzed in a few hours at a hospital laboratory.

FDA's decision to approve the test was based on a review of safety and effectiveness data submitted by the manufacturer and on the recommendation of the Immunology Devices Panel of FDA's Medical Devices Advisory Committee.

Biomira used the test on blood specimens from 166 women who had had breast cancer previously and who were studied in clinical trials at five sites in the United States. The women were also evaluated with radiographic procedures. The test found cancer antigen in 15 of 26 women (58 percent) who had a recurrence. It also indicated cancer in 8 of 140 patients who did not have it.

Because the test did not detect the cancer antigen in all cases and detected it falsely in others, FDA based its approval on use of the test in conjunction with other procedures to monitor the recurrence of Stage II or Stage III breast cancer.

REPORT SERIOUS ADVERSE EVENTS AND PRODUCT PROBLEMS TO MEDWATCH
1-800-FDA-1088