NEW YORK (GenomeWeb News) – The US Food and Drug Administration said today it has approved a genetic test to help healthcare professionals determine whether breast cancer patients are candidates for Herceptin (trastuzumab).
The test called Inform Dual ISH allows for the measurement of the number of copies of the HER2 gene in a small sample of breast tumor tissue. An excessive amount of the protein produced by the gene has been found in some cancers, including breast cancer. Detection of the number of copies of the HER2 gene enables lab personnel to count copies of chromosome 17 — where the HER2 gene is located — and HER2 genes on the same slide.
While fluorescence microscopes allow this same feature, the Inform Dual ISH enables the viewing of HER2 and chromosome 17 signals directly under a microscope for longer time periods, the FDA said.
Used with other clinical information and laboratory tests, the Inform Dual ISH test can provide clinicians additional information on which to base treatment decisions, said Alberto Gutierrez, director of the Office of In Vitro Diagnostic Device Evaluation and Safety in the FDA's Center for Devices and Radiological Health.
The test is manufactured by Ventana Medical Systems, which is part of the Roche Group. Herceptin is made by another Roche company, Genentech.
The FDA approved the test based on a study of tumor samples from 510 patients with breast cancer, which showed that the test could confirm a patient's tumor sample contained more than the normal copies of the HER2 gene in 96 percent of the HER2-positive tumor samples. Patients with high numbers of the copies of the HER2 gene are considered candidates for Herceptin therapy.
Inform Dual ISH also was shown to be effective in excluding the possibility that more than the normal copies of the HER2 gene were present in 92 percent of the HER2-negative tumor samples, FDA said. Patients with less than the normal number of copies of the HER2 gene are not typically considered candidates for Herceptin treatment.
In 2008 Invitrogen, now part of Life Technologies received PMA approval from FDA for its test for assessing which breast cancer patients are suitable for Herceptin. In October, FDA cleared Dako's tests for the use of Herceptin for metastatic gastric or gastroesophageal junction adenocarcinoma.
These two tests are among a handful already cleared by FDA for HER2 testing. Abbott Molecular's Vysis unit sells the PathVysion FISH assay, which has been on the market for several years for assessing HER2 status.
Dako was the first to receive such clearance in 1998, when FDA approved its HercepTest simultaneously with Herceptin.