New, effective and less toxic therapeutic option for patients with HER2-positive breast cancer

Patients with HER2-positive breast cancer, a particularly aggressive form of breast cancer, now have a new, effective and less toxic therapeutic option.

On Friday, Feb., 22, the Food and Drug Administration (FDA) approved the new treatment drug, Kadcyla (trastuzumab emtansine), also known as TDM-1, which combines Traztuzumab, also called Herceptin, with the powerful chemotherapy drug emtansine.

The drug therapy is developed by Roche-owned Genentech, which funded the study.

Results from clinical trials of the drug TDM-1, known as "Super Herceptin", showed that it was more effective and less toxic than the standard regimen for this type of tumor. The medication kept patients free of disease for longer than the standard chemotherapy regimen.

Rush was one of only two medical centers in Illinois and a small number across the country studying the treatment.

HER-2 positive breast cancer patients have been found to be positive for carrying a protein that promotes the growth of cancer cells. TDM-1 is taken directly to cells that have the HER2 protein on the membrane, such as the cancer cells, while sparing normal cells. This results in less toxicity from the chemotherapy drug.

"TDM-1 works like the original drug Herceptin by hunting down and interfering with the cancer cells," said Dr. Melody Cobleigh, Director of the Comprehensive Breast Center at Rush and lead investigator of the TDM-1 clinical trials at Rush. "But this newer version, called TDM-1, is Herceptin with a chemotherapy drug attached. The combination delivers a one-two punch, seeking out the cancer cells and not only stopping growth but delivering the chemo right to the cell."

"The tumor cell basically eats the TDM-1 and then, the TDM-1 gets released and destroys the tumor cell from the inside out," said Cobleigh.

"The best part for patients is that it is very tolerable and does not have the debilitating side effects characteristic of other cancer drugs," said Cobleigh.

With TDM-1, patients did not even lose their hair and experienced far fewer other side effects.

"This really can have an impact on patient's lives," said Cobleigh.

About 1,000 patients with HER-2 positive breast cancer were enrolled in the Phase III, randomized, multicenter, trial of TDM-1. One group of patients received TDM-1 and the other group received two standard chemotherapy drugs. The TDM-1 patients remained cancer-free for 9.6 months - progression-free survival - while the standard treatment group was cancer-free for 6.4 months. Progression-free survival is the time that elapses between the start of a treatment and the time the cancer gets worse.

"This therapy has shown to be effective when other standards treatments have stopped working," said Cobleigh. "For men and women, the treatment gave them the opportunity to lead normal lives."

Source: Genentech