A combination of a "targeted" therapy and chemotherapy shrank metastatic brain tumors by at least 50 percent in one-fifth of patients with aggressive HER2-positive breast cancer, according to data presented by Dana-Farber Cancer Institute investigators at the San Antonio Breast Cancer Symposium.
Lapatinib (Tykerb) and capecitabine (Xeloda) were paired in an extension of a Phase 2 clinical trial in which lapatinib given alone shrank brain metastases significantly in six percent of 241 patients.
In the extension trial, capecitabine was added to lapatinib in 49 patients whose metastases -- cancerous colonies in the brain spread from their primary cancer -- had progressed while on treatment. With the combination therapy, brain metastases shrank by 20 percent or more in 18 patients (37 percent) and shrank by at least 50 percent in 10 patients (20 percent), reported Nancy Lin, MD, of Dana-Farber's Breast Oncology Center.
"Very few medications have shown activity in the treatment of brain metastases, particularly in HER-2-positive metastatic breast cancer patients," said Lin, who led the study with Eric Winer, MD, director of the Dana-Farber Breast Oncology Center. "Therefore, these data are quite encouraging, and further studies are warranted."
The data (abstract 6076) will be presented on Sunday, Dec. 16 at 7 a.m. CT.
Lapatinib is an oral small-molecule drug from GlaxoSmithKline that is approved along with capecitabine for treating patients with advanced or metastatic breast cancer whose tumors are driven by the abnormal growth signal, HER-2, and who have already undergone therapy including trastuzumab (Herceptin), a taxane drug, and an anthracycline compound. Lapatinib, like trastuzumab, blocks the HER-2 signal.
Up to one-third of women with advanced, HER-2-positive breast cancer may develop metastases to the brain.
"Although radiation treatment is often effective, as women live longer with metastatic cancer, some develop worsening of brain metastases despite radiation," said Lin. "Because cancer in the brain can have a major impact on quality of life, it is important to have treatment options to address this problem."