The addition of carboplatin to a standard neoadjuvant chemotherapy regimen boosted pathologic complete response in patients with triple negative breast cancer, according to the results of a study presented at the 2013 San Antonio Breast Cancer Symposium.
Breast cancers that are not stimulated to grow from exposure to estrogen or progesterone and are HER2-negative are called triple-negative breast cancers. Triple-negative breast cancers tend to be more aggressive than other breast cancers and have fewer treatment options.
Standard neoadjuvant treatment for triple-negative breast cancer consists of anthracycline- and taxane-based chemotherapy; however, researchers continue to evaluate whether additional drugs can improve response rates.
The Cancer and Leukemia Group B (CALGB)/Alliance 40603 study included 454 patients with stage II/III triple-negative breast cancer. Patients were randomly assigned to standard neoadjuvant chemotherapy or standard therapy plus carboplatin, Avastin® (bevascizumab), or both. The primary endpoint was pathologic complete response in the breast, and a secondary endpoint was pathologic complete response in the breast and the axillary nodes.
The results indicated that the addition of carboplatin significantly increased the pathologic complete response in the breast and in the breast plus axillary nodes.
Among patients receiving carboplatin, 60 percent achieved a pathologic complete response in the breast, compared to 46 percent of patients who did not receive carboplatin. What’s more, 54 percent of those receiving carboplatin experienced complete pathologic response in the breast and axillary nodes, compared with 41 percent of those not receiving carboplatin. This represented a 71 percent increase.
Avastin was active also and showed a significantly improved response in the breast, but not in the breast plus axillary nodes. Avastin proved to be more toxic; however. The total number of patients with serious adverse events was 46 in the chemotherapy plus carboplatin/Avastin group and 39 in the chemotherapy plus Avastin group, compared with 29 in the chemotherapy plus carboplatin group and 15 in the chemotherapy alone group.
The researchers concluded that carboplatin is a reasonable addition to standard neoadjuvant chemotherapy for triple-negative breast cancer. It increases the likelihood of response in the breast and axillary nodes, with acceptable toxicity levels.
Sikov WM, Berry DA, Perou CM, et al: Impact of the addition of carboplatin and/or bevacizumab to neoadjuvant weekly paclitaxel followed by dose-dense AC on pathologic complete response rates in triple-negative breast cancer. 2013 San Antonio Breast Cancer Symposium. Abstract S5-01. Presented December 13, 2013.