SABCS 2011: Dual HER2 Blockade Significantly Extends Progression-Free Survival
Results of the CLEOPATRA (CLinical Evaluation Of Pertuzumab And TRAstuzumab) trial will be presented today at the 34th Annual CTRC-AACR San Antonio Breast Cancer Symposium and are also published in the New England Journal of Medicine. These findings suggest that the combination of two HER2 blocking agents, trastuzumab and pertuzumab, when used with docetaxel, prolongs progression-free survival compared to treatment with trastuzumab and docetaxel alone.
In the CLEOPATRA trial, researchers randomly assigned 808 patients with HER2-positive metastatic breast cancer to receive placebo plus trastuzumab plus docetaxel (control group) or pertuzumab plus trastuzumab plus docetaxel (pertuzumab group) as first-line treatment until the time of disease progression or the development of unmanagable toxic effects. The median (independently assessed) progression-free survival was prolonged by 6.1 months with the addition of pertuzumab, from 12.4 months in the control group to 18.5 months in the pertuzumab group. The objective response rate, measured by tumor shrinkage of at least 30%, was 69.3% in the control group, as compared with 80.2% in the pertuzumab group. No additional cardiac toxicity was observed in the pertuzumab group. It is too early for an overall survival analysis, which is estimated to be performed in late 2013.
According to first author José Baselga, M.D., Ph.D. of Harvard Medical School, “Most metastatic patients with HER2-positive breast cancer eventually stop responding to trastuzumab, so the fact that we now have an agent that can be added to current treatment to delay progression is very exciting.”