A combination drug, Tykerb, known generically as lapatinib, appears to be able to fight breast cancer that has spread to the brain, media reported Tuesday.

For the first time, researchers have shown that the drug can slash the number of cancer stem cells in women with breast cancer, curbing tumor growth.

The latest theory of what causes cancer namely is that stem cells hiding within tumors drive their growth. Conventional treatments fail to cure cancer, according to the theory, because they are targeting the wrong cells.

Six weeks of Tykerb treatment slashed the number of breast cancer stem cells by more than half in 30 women studied, and two-thirds were cancer-free after follow-up treatment, says Jenny Chang, MD, of Baylor University in Houston.

The finding is significant because up to one third of women with HER2-positive advanced breast cancer may develop brain metastases.

(Agencies via Xinhua December 19, 2007)