Risk Class May Be Linked to Response to Breast Cancer Treatments
Posted: Thursday, December 13, 2018
New results from the I-SPY 2 trial, which were presented at the 2018 EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics (Abstract 2), concluded that stratifying patient gene signatures into ‘high-risk’ and ‘ultra–high-risk’ groups may help predict sensitivity to chemotherapy agents and treatment combinations in patients with early breast cancer. “This will allow us to tailor treatment further so that the right anticancer [treatments] can be given to the right patients who have the highest chance of response and that patients who are unlikely to respond can be prioritized to receive another therapy,” said Laura J. van ‘t Veer, PhD, of the University of California, San Francisco, in a press release from the European Organisation for Research and Treatment of Cancer (EORTC), the National Cancer Institute (NCI), and the American Association for Cancer Research (AACR).
A total of 986 patients were classified as high risk (MP1) or ultra–high risk (MP2) using the 70-gene prognostic signature. Half of these patients were identified as being MP2. The MP2 group was made up primarily of those with triple-negative breast cancer. The majority of the MP1 group had hormone receptor–positive HER2-negative disease and hormone receptor–positive, HER2-positive disease.
Patients designated as being MP2 were 2.62 times more likely to have a pathologic complete response than were those ranked as MP1. When the results were adjusted based on which treatment patients had received and whether or not their cancer was driven by hormones or HER2 receptors, MP2 patients had a pathologic complete response rate that was 2.43 times higher than did MP1 patients.
In a further analysis, the investigators found that treatment choice seemed to affect outcomes as well. For instance, MP2 patients were more likely to achieve pathologic complete response if they were taking veliparib/carboplatin, neratinib, ganitumab, ado-trastuzumab emtansine/pertuzumab, or pembrolizumab in addition to the standard paclitaxel treatment alone or in combination with trastuzumab.
In addition, the type of receptor also appeared to impact response to treatment. For example, MP2 patients with hormone receptor–positive and HER2-positive disease were 3.62 times more likely to achieve pathologic complete response than MP1 patients; however, MP2 patients who had hormone receptor–positive and HER2-negative disease were 3.2 times more likely to achieve pathologic complete response than MP1 patients. However, this was not found in those with hormone receptor–positive and HER2-negative disease.
