The FDA has approved a new genetic test that will help health-care professionals determine whether women with breast cancer are HER2-positive and, therefore, candidates for trastuzumab (Herceptin). The test, called Inform Dual ISH, allows for measurement of the number of copies of the HER2 gene in tumor tissue.
The FDA based its approval of the Inform Dual ISH on a U.S. study involving tumor samples from 510 patients with breast cancer. This study showed that the test was effective in confirming that a patient’s tumor sample contained more than the normal number of copies of the HER2 gene in 96% of the HER2-positive tumor samples. Patients with more than the normal number of copies of the HER2 gene are considered candidates for trastuzumab therapy.
The study also showed that the test was effective at excluding the possibility that more than the normal number of copies of the HER2 gene were present in 92.3% of the HER2-negative tumor samples. Patients who do not have more than the normal number of copies of the HER2 gene are typically not candidates for trastuzumab therapy. ■
