Reporting at the annual San Antonio Breast Cancer Symposium, researchers say the experimental drug, Tykerb, halted the growth of inflammatory breast cancer.
If the findings can be repeated in larger studies, the experimental cancer drug may offer a new targeted approach to fighting highly deadly breast tumors, says Eric Winer, MD, head of breast cancer at the Dana-Farber Cancer Institute in Boston and moderator of the session at which the research was presented.
Symptoms of Inflammatory Breast Cancer
While it represents only about 1% of breast cancer diagnosed in the U.S., inflammatory breast cancer is extremely aggressive, says researcher Massimo Cristofanilli, MD, associate professor in the department of breast medical oncology at the University of Texas M.D. Anderson Cancer Center in Houston.
Unlike other breast tumors that are characterized by a lump, symptoms of inflammatory breast cancer include redness, swelling, and warmth in the breast.
The skin may appear reddish, purple, or bruised, and have ridges. Other symptoms include burning, aching or tenderness, an increase in breast size, and an inverted nipple.
Due to both its rapid growth and unusual symptoms, inflammatory breast cancer is often not diagnosed until after the disease has spread to other parts of the body, Cristofanilli tells WebMD. About 60% of women are dead five years later.
The new study is the first to test a treatment specifically for this condition, according to Cristofanilli.
Developed by GlaxoSmithKline, Tykerb zeroes in on two related proteins -- HER2 and EGFR -- that sit on the surface of inflammatory breast cancer cells and play a critical role in the growth and spread of the cancer.
In excess, both HER2 and EGFR are some of the worst culprits instigating cancer spread. They have a direct effect on cancer cells, stimulating the cells to proliferate, migrate, and spread.
Tykerb attaches to these proteins, thereby blocking their action and slowing or stopping the growth of tumor cells.
GlaxoSmithKline is a WebMD sponsor, and the company supported this research.
Breast Tumors Shrink
The researchers studied two groups of women: 30 women whose tumors had high levels of HER2, and five women whose tumors had high levels of EGFR but not HER2.
All took one Tykerb pill once a day for at least two weeks. Then, for three months, they added a common chemotherapy drug, paclitaxel, once a week. That was followed by surgery.
Results showed that tumors shrank by at least 50% in 30 of the 35 women. The disease progressed in only one woman.
Of the 21 women who had completed surgery, three showed no evidence of breast cancer under the microscope. According to Cristofanilli, this indicates a good response and possibly improved inflammatory breast cancer survival.
Tykerb was generally well-tolerated. Side effects included mild skin rashes and diarrhea that could be easily treated with over-the-counter medications, he says.
"While preliminary, the findings are encouraging, suggesting that in this group of women, [Tykerb] plus paclitaxel is a very effective and easy therapy," Dana-Farber's Winer tells WebMD.
SOURCES: San Antonio Breast Cancer Symposium, Dec. 14-17, 2006. Massimo Cristofanilli, MD, associate professor, department of breast medical oncology, University of Texas M.D. Anderson Cancer Center, Houston. Eric Winer, MD, head of breast cancer, Dana-Farber Cancer Institute, Boston.
By Charlene Laino
Reviewed by Michael Smith