The first-of-its-kind drug, called Kadcyla from Roche, combines the established drug Herceptin with a powerful chemotherapy drug and a third chemical that links the two medicines together. That chemical keeps the mixture intact until it binds to a cancer cell, delivering a strong dose of anti-tumor poison.
Researchers say the drug is a crucial step forward, since it delivers more medication while reducing the unpleasant side effects of chemotherapy.
Dr. Melody Cobleigh of Rush University Medical Center says the new drug seeks out tumor cells, gets internalized and explodes from within.
"It's a revolutionary way of treating cancer," said Cobleigh, who helped conduct the key studies of the drug at the Chicago facility.
The FDA approved the new drug for about 20 percent of breast cancer patients with a more aggressive form of the disease that is typically less responsive to hormone therapy.
According to the National Cancer Institute, breast cancer is the second most deadly form of cancer in U.S. women, and is expected to kill more than 39,000 Americans this year.
Roche's Genentech said Friday that Kadcyla will cost $9,800 per month, compared to $4,500 per month for regular Herceptin. The company estimates a full course of Kadcyla, about nine months of medicine, will cost $94,000.
The FDA said it approved the drug based on company studies showing Kadcyla delayed the progression of breast cancer by several months. Overall, patients taking Kadcyla lived about 2.6 years, compared with 2 years for patients taking the other drugs.
Kadcyla will carry a boxed warning, the most severe type, alerting doctors and patients that the drug can cause liver toxicity, heart problems and potentially death. The drug can also cause severe birth defects and should not be used by pregnant women.
The Associated Press contributed to this report.