NEW YORK (GenomeWeb News) – Monogram Biosciences said today that the Dana-Farber Cancer Institute has agreed to evaluate its HERmark breast cancer assay in metastatic breast cancer.
The goal of the project is to test HERmark cutoff values and determine whether the assay is better than conventional methods for identifying metastatic breast cancer patients who are susceptible to Genentech’s Herceptin (trastuzumab) treatment.
The researchers will use HERmark, an assay that measures total HER2 protein and HER2 homodimer levels, to analyze roughly 600 tissue samples from breast cancer patients — half of whom are believed to be eligible for Herceptin treatment based on HER2 immunohistochemistry and/or fluorescence in situ hybridization tests. The researchers will then compare the HERmark measurements with IHC and FISH results and with Herceptin treatment response.
Monogram believes that the HERmark assay could lead to a reclassification of as many of 15 to 20 percent of patients currently classified as HER2-negative and that it may also uncover HER2-positive patients with varying Herceptin treatment response.
“Results from prior studies in metastatic breast cancer have suggested that HERmark can identify subsets of patients with different responses to Herceptin even though they had all been previously assessed as ‘HER2-positive’ by IHC and/or FISH, tested centrally,” Michael Bates, Monogram’s vice president of clinical research, said in a statement.
Bates noted that the researchers also plan to measure HER3 expression levels in breast cancer tumors and determine whether they relate to clinical outcomes. And, he said, the tissue obtained for the study may facilitate testing of newer assays currently in advanced development at Monogram — for instance, tests that gauge HER1 or p95 expression and tests for HER2 heterodimers.