Researchers led by Dr Ian Krop from Dana-Farber Cancer Institute have found that a new hybrid agent - called T-DM1 – can play a vital role in either stalling the growth of metastatic HER2 positive breast cancer in women or, at least, shrinking the tumor in most patients.

Noting the positive effect of the new antibody drug on most patients whose metastatic HER2-positive cancer had become resistant to standard therapies, the researchers found that the total clinical benefit rate of T-DM1 was approximately 53 percent.

Specifically speaking, the researchers, presenting their study at the 32nd annual CTRC-AACR San Antonio Breast cancer Symposium, said that while the T-DM1 helped shrink tumors by over 30 percent in nearly 40 percent patients, it led to at least six-month stability of the cancer in another 13 percent.

Elaborating about T-DM1, the researchers said that the hybrid agent consisted of the cell-killing drug, DM1. It is chemically linked to the monoclonal antibody ‘trastuzumab,’ which discriminatingly attaches itself to the HER2 growth signal receptor that is highly over-expressed in HER2-positive breast tumors.

About the role of T-DM1, Krop said: “The antibody binds to the HER2 protein on tumor cells and delivers DM1 selectively to them – but not to normal cells. This allows us to deliver high doses of the chemotherapy directly to tumor cells. And at the same time, the antibody continues to block the HER2 growth signals.”