Drugs to Block CD73 Successfully Target Chemo-Resistant TNBC

A news release from Centre hospitalier de l'Université de Montréal (edited by Pat to eliminate fearful language]:

MONTREAL, June 26, 2013 /CNW Telbec/ - An international research team of Canadian and Australian scientists have found that an enzyme in triple-negative breast cancer makes patients less responsive to chemotherapy. 

Triple negative breast cancer accounts for 15% of all breast cancers and is characterized by the absence of three key receptors (oestrogen receptor, progesterone receptor and the human epidermal growth factor receptor 2). Standard treatment, such as hormone therapy, cannot be used for triple negative breast cancer.

In a study published in the online version of the Proceedings of the National Academy of Sciences of the United States, the team found that CD73 made the breast cancer more resistant to chemotherapy with anthracyclines. This drug works not only by killing the tumour cells, but also by activating the body's anti-tumour immune response.

The research revealed that the overexpression of CD73 inhibits the body's immune response to cancer. Moreover, the heightened presence of CD73 is associated with a higher risk of distant metastases, the principal cause of death in breast cancer.

"These results are quite encouraging," says John Stagg, M.D,  assistant professor in the Faculty of Pharmacy at the University of Montreal and a researcher affiliated with Montreal Cancer Institute. "Because they suggest that therapies specifically designed to block the action of CD73 could make it possible to enhance the beneficial effects of anthracycline-based therapies." Indeed, in experiments with laboratory animals, Stagg's team showed that combining standard anthracycline treatment with anti-CD73 therapy prolonged survival by over 50%. More research is required to determine whether anti CD73 therapies can also be effective with other chemotherapeutic agents.

Human trials of inhibitors of CD73 could begin within five years, meaning that there is hope on the horizon for triple negative breast cancer patients.