Nexavar Slows the Progression of Breast Cancer

A drug that treats liver and kidney cancers delayed locally recurrent or metastatic HER2-negative breast cancer in two phase 2 studies presented Friday at the San Antonio Breast Cancer Symposium.

Nexavar (sorafenib), when tested in patients with newly diagnosed advanced disease, slightly extended median progression-free survival—the amount of time the cancer did not progress—from 5.6 months with Taxol (paclitaxel) alone to 6.9 months with Nexavar plus Taxol, which translates to a 21 percent reduction in the risk of progression or death.

Of the 20 deaths seen in the trial, 17 were in patients from India. Although most were unrelated to treatment, the deaths skewed progression-free survival data for the Nexavar arm, said lead investigator William Gradishar, MD, during a press briefing. Gradishar, of Robert H. Lurie Comprehensive Cancer Center at Northwestern University, told reporters it wouldn’t be feasible to tease out the patients from India since they made up the majority of the 237 study participants.

The second study compared a combination of Nexavar plus the chemotherapy drug Xeloda (capecitabine) to Xeloda alone in patients who had received no more than one prior chemotherapy treatment for advanced disease. Median progression-free survival for patients in the Nexavar group reached 6.4 months versus 4.1 months in the Xeloda-only group, translating to a 42 percent reduction in disease progression or death. The benefit became more pronounced when researchers analyzed patients who had no prior therapy: progression-free survival hit 7.6 months with Nexavar compared with 4.1 months without the drug. A phase 3 trial testing Nexavar and Xeloda in advanced breast cancer is scheduled to start next year, said investigators.

Data on overall survival were not available for either study.

Hand-foot syndrome—pain, swelling, or numbness of the hands or feet—is a common side effect of Nexavar that may require dose reductions or treatment delays. Other side effects can include diarrhea and rash.

Nexavar is an oral agent that inhibits the formation of new blood vessels to the tumor, a process known as angiogenesis. Less impressive were studies presented Friday testing two other angiogenesis inhibitors in HER2-negative advanced breast cancer. Sutent (sunitinib), a drug approved for advanced kidney cancer and gastrointestinal stromal tumor, proved less effective than Xeloda in previously treated patients, and the experimental drug motesanib failed to outperform Avastin (bevacizumab) as a first-line treatment.

This article is a part of CURE’s 2009 San Antonio Breast Cancer Symposium coverage. To read more articles from SABCS 2009, visit sabcs2009.curetoday.com.