New dual-target therapy offers hope for better breast cancer treatment

Researchers, led by the University of Melbourne's Professor Laura Mackay, a Laboratory Head and Immunology Theme Leader at the Peter Doherty Institute of Infection and Immunity (Doherty Institute), in collaboration with Pfizer, have discovered new insights into possible future treatments for breast cancer. 

A new dual-target drug that has been shown to supercharge cancer-fighting immune cells in mice may support a new treatment approach for patients, potentially paving the way for improved outcomes in breast cancer care. 

Breast cancer is the fifth most common cause of cancer death in Australia, with more than 20,000 Australians diagnosed per year. Over 1,000 of those diagnosed are young Australian women under 40. There is an urgent need to discover more effective treatments for breast cancer. 

Immunotherapy represents one of the most promising new treatments for cancer, by boosting the body's own immune cells to kill cancer cells. However, only a small proportion of breast cancer patients respond to existing immunotherapy treatments. 

Results from a new study published in Clinical and Translational Immunology found that dual-target antibody therapy can enhance cancer-fighting T cells more effectively than current single-target therapy in mice. Professor Mackay explained the importance of this research for cancer patients. 

We need to find new ways to instruct the immune system to fight cancer. 

Our research shows that a two-pronged strategy can better ignite cancer-fighting immune cells, which is the goal of immunotherapy." 

Professor Laura Mackay, Laboratory Head and Immunology Theme Leader at the Peter Doherty Institute of Infection and Immunity

Some cancer cells are coated with proteins that allow them to hide from immune cells and continue to grow. In a research collaboration with Pfizer Inc. two such proteins, CD47 and PD-L1, were 'unmasked', exposing the cancer cells to the immune system for destruction. 

While therapies targeting CD47 and PD-L1 have been tested individually, they both present limitations such as toxicity to patients or poor response rates. Therefore, dual-target antibody therapy that can maximize their anti-cancer functions while minimizing these obstacles was explored. 

Lead author of the study, the University of Melbourne's Dr. Susan Christo, Senior Research Officer at the Doherty Institute, described how this research may influence treatment approaches for breast cancer patients in the future. 

"The idea that cancer-fighting immune cells can gain more power when we target multiple key proteins at once may be a real game-changer in the field of immunotherapy," said Dr Christo. 

"Our work opens up new opportunities to explore how different combinations of drugs can supercharge the immune system to beat cancer. 

"The advantage of a dual-target approach is that it can be used for a wide range of solid cancers. This means that more patients could benefit from its anti-cancer function, inspiring us to do more research with the hopes of going to clinical trials." 

This research study was made possible with thanks to funding from Pfizer Inc. and the National Health and Medical Research Council (NHMRC).