EVENTS | VIEW CALENDAR
Companions in companion diagnostics
PLEASANTON, Calif.—Roche Molecular Systems Inc. recently announced a research collaboration with Merck Sharp & Dohme Corp., a subsidiary of Merck & Co. Inc., that provides Merck access to Roche's developmental microarray-based AmpliChip p53 Test.
The AmpliChip p53 Test is designed to detect mutations in the tumor suppressor gene p53, as the 53 protein is a critical component of normal cell response to various stress types including damaged genetic material. By identifying cancers that harbor a dysfunctional p53 gene, the companies aim to achieve better treatment outcomes in cancer patients by determining which patients are most likely to respond to certain investigational therapeutic candidates.
The p53 protein functions by activating DNA repair proteins, inducing growth arrest for repair of DNA damage, and by initiating apoptosis in the case of irreparable DNA damage. When p53 function is deficient, a cell's response to DNA damage is severely impaired, contributing to tumor growth and increasing tumor cells' resistance to chemotherapy. Roche's investigational AmpliChip p53 Test is designed to detect damage to p53 DNA in tumor cells in order to identify which cells carry dysfunctional p53 proteins that can lead to treatment resistance.
Roche's AmpliChip technology combines leading DNA amplification and detection technologies to screen for genetic mutations in cells: the Roche polymerase chain reaction to amplify or make copies of genetic material, and Affymetrix high-density microarray technology to capture and scan the amplified DNA. The combination of these two technologies in AmpliChip is intended to enable physicians and laboratories to determine when mutations are present and to predict the effect those mutations could have on patients' response to medical treatment.
According to Karin Bauer, a spokesperson for Roche, the AmpliChip p53 Test is only being offered for use by Merck and there are no arrangements to share access to the test with other companies at this time.
The development of the AmpliChip p53 Test is very much focused on the purpose of investigational use as a companion diagnostic test in cancer clinical trials, she says, adding, "it is possible that Roche's AmpliChip p53 Test could be used for other applications in the future; however, it is too soon to tell what those applications might be. The p53 gene mutation has wide-ranging effect in cells, so while Roche is developing the test as an investigational companion diagnostic together with therapeutic candidates in cancer clinical trials today, Roche wouldn't rule out investigating its applications in other areas in the future."
At this point, Bauer says, because of p53's wide-ranging effects, it is difficult to pinpoint precisely which cancers would be best suited for a p53 mutation test. But she notes that p53 mutations in breast cancer have been associated with poor patient outcomes, regardless of treatment. Similarly, patients with chronic lymphocytic leukemia who carry mutations in the p53 gene have been shown to have shorter survival time.
Because the AmpliChip p53 Test is being used as an investigational companion diagnostic in clinical trials, Roche would file the test for approval at the same time as the investigational therapeutic candidate that it was tested together with, Bauer explains.
"Until additional information becomes available from clinical trials in development, it is too early to say when Roche might file for approval of the test or an investigational therapeutic candidate," she adds. "For the same reason, it's too early to speculate about commercialization."