The drug lapatinib shrank tumors and slowed progression of brain metastases in some patients with advanced breast cancer, according to results of a clinical trial presented by Dana-Farber Cancer Institute scientists at the annual meeting of the American Society of Clinical Oncology.
Researchers said the drug, also known as Tykerb, should undergo further testing in combination with other drugs as a treatment for breast cancer that has spread to the brain.
"Results of this study indicate that lapatinib, when given alone, has modest but real activity against brain metastases in women who have had multiple prior treatments for their breast cancer," said Dana-Farber's Nancy Lin, MD, the study's lead author.
The trial examined the tolerability and efficacy of lapatinib in a Phase II study that included 241 patients who had been treated with the drug Herceptin for stage IV HER2-positive breast cancer, and had developed metastases to the brain. About 30 to 40 percent of women treated with Herceptin for stage IV breast cancer are diagnosed with brain metastases.
Brain tumors shrank significantly in what was termed a ,partial response, in 15 patients (6 percent). Across all 241 patients, there was a period averaging 15 weeks before the disease progressed again. About one-fifth of patients did not experience any worsening of their disease for 6 months or longer.
Eric Winer, MD, of Dana-Farber, is the study's senior author. Other authors are from centers in several European countries, and from GlaxoSmithKline.
Data from all 241 patients was to be presented at the ASCO meeting.
"Our data provides evidence that lapatinib has activity based on tumor volume reductions in some patients with progressive HER2-positive disease of the central nervous system after being treated with Herceptin and radiation," the researchers said.