WHEN THE U.S. FOOD & DRUG ADMINISTRATION approved the use of Herceptin to treat advanced breast cancer 11 years ago, Dennis Slamon, M.D., predicted that the new therapy would someday become one arrow in a quiver of molecularly focused drugs that target tumor cells, while leaving healthy cells alone. It appears that he was right.
Dr. Slamon has a good vantage point from which to view recent developments. His research at UCLA directly led to the development of Herceptin, and has earned him worldwide recognition, including more than two-dozen national and international awards. Today, Herceptin is accepted as the standard of care for the 20 percent of women with breast cancer who have the HER2 mutation. And Dr. Slamon is confident that new treatments deriving from clinical trials now underway will offer even more potent therapies. “The one-size-fits-all approach for the major cancers, including and especially for breast cancer, was not as effective as it could have been,” says Dr. Slamon, who is the director of clinical/translational research at UCLA’s Jonsson Comprehensive Cancer Center. “What we’ve been doing here is trying to design therapies very specifically for what’s driving the cancer and develop something that is more effective and less toxic.”
In the 11 years since it was approved, Herceptin has been tested against breast cancer in clinical trials with different chemotherapy combinations. In two studies, one pairing Herceptin with Avastin, a drug that attacks tumors by inhibiting the growth of new blood vessels, and one combining it with an inhibitor of the epidermal growth factor receptor, Tarceva, chemotherapy was removed from the mix entirely. And Herceptin is currently being tested in a large international trial paired with chemotherapy and Avastin.
In early-stage breast cancer trials, Herceptin paired with chemotherapy significantly increased disease-free survival time. The study also tested Herceptin with a chemotherapy combination that eliminated Adriamycin, an anthracycline that is commonly used to treat breast cancer but which, when used with Herceptin, can cause heart damage. That altered regimen also significantly improved disease-free survival.
Oncologists have been reluctant to remove Adriamycin from their arsenal, but Dr. Slamon says that his study definitively proved it is possible to get the same result without it, which may lead to yet another paradigm shift in treatment for breast cancer.
The Herceptin-Avastin and Herceptin-Tarceva studies also have been promising. But UCLA oncologists are most excited to see results from the large international study.
Ultimately, Dr. Slamon says, “we hope these studies will lead to another very effective treatment option for women with breast cancer.”