A new and convenient test for breast cancer patients to identify potential candidates for Trastuzumab therapy more easily has been devised. The HER2 gene can be stained and seen under a standard microscope.
FDA Clears Improved HER2 Test in Breast Cancer
The FDA has approved a new quantitative test for HER2 genes in breast tumor samples that can be performed under a standard microscope, potentially making it easier to identify patients who would benefit from trastuzumab (Herceptin) therapy.
Called Inform Dual ISH, the test allows clinical lab personnel to count the number of HER2 gene copies on chromosome 17 visually under a microscope. It is based on a staining system that colors chromosome 17 red and the HER2 gene black.
Such assessments are possible with previous methods but they require fluorescence microscopes, the FDA explained in announcing the approval. Also, the Dual ISH system makes the HER2 and chromosome 17 copies visible for longer periods.
The agency said the approval was based on a U.S. study involving tumor samples from 510 patients with breast cancer.
It showed that the test was 96% sensitive in identifying HER2-positive tumor samples and 92.3% specific in ruling out HER2 positivity in samples that had the normal number of copies of the HER2 gene. Patients with more than the normal number of copies of the HER2 gene are considered candidates for trastuzumab therapy, whereas those with the normal number are not.
The Inform Dual ISH test is manufactured by Ventana Medical Systems of Tucson, Ariz.