New drug combination may overcome breast tumors’ Herceptin resistance

A new drug combination has been shown to overcome breast cancer tumors’ resistance to the targeted drug Herceptin.

An MD Anderson Cancer Center study at the University of the Texas found that the drug saracatinib, when added to Herceptin treatment, shrinks previously resistant tumors by cutting off at least five different pathways to cancer growth.

Saracatinib inhibits SRC, a known cancer-promoting protein, from thriving and allows Herceptin to work again in tumors that have a high amount of the HER2 protein. Only about 26 percent of women with HER2-positive breast cancer respond to Herceptin as single therapy, while 40 to 60 percent of women respond to the drug when combined with other chemotherapy.

“Scientists have identified so many ways by which a tumor resists Herceptin that it raises an important issue for treatment,” says senior study author Diana Yu. “This combination is a promising therapy for those with Herceptin-resistant breast cancer.”

Yu said saracatinib has been tested in phase I and phase II clinical trials as a single treatment against late-stage cancers and has a favorable side effects profile. Combining Herceptin and saracatinib to treat resistant tumors in mice reduced tumor volume by 90 percent in 25 days.

The complete study appears in the journal Nature Medicine. Additional information on this drug combination is available through this article at Science Newsline.

April 21, 2011