Shining new light on immunotherapy for breast cancer

Immunotherapy that enhances the body’s immune response has transformed the landscape for cancer treatment.

These treatments have led to unprecedented survival outcomes in some cancer types, but not all patients are seeing the same benefits.

In a recent review published in Cancers, Dr Maggie Cheang and Dr Milana Bergamino Sirvén from The Institute of Cancer Research, highlight the challenges and opportunities in developing new and more tailored immunotherapy drugs, including for breast cancer.

A central challenge with immunotherapy treatment is that it’s hard to predict which patients will respond. Some patients have immunogenic, or ‘hot’, tumours that are more likely to respond to immunotherapy than ‘colder’ ones.

“With immunotherapy there are lights and shadows,” review co-author Dr Bergamino Sirvén, Clinical Research Fellow in Integrative Genomic Analysis at the ICR’s Clinical Trials and Statistics Unit (ICR-CTSU), explains. “We’ve seen incredible success in treating inherently immunogenic tumours. However, other cancer types may have a more nuanced connection with the immune system that is more difficult to unpick. These are the shadows.”

Immunotherapy for cancer

Immunotherapy includes treatments ranging from cancer vaccines and oncolytic viruses to antibody-based targeted therapies. One of the most prevalent forms of immunotherapy is immune checkpoint inhibitors, protein-blocking drugs which allow T-cells to perceive cancer cells as targets and attack them.

These drugs have been especially successful in more immunogenic cancers such as melanoma, non-small cell lung cancer and kidney cancer.

However, there is still hope that some patients with less immunogenic cancers may also benefit from immunotherapy. These cancers, including some types of breast cancer, are considered ‘colder’ tumours because of the low numbers of tumour-infiltrating types of white blood cells.

But there are some patients with these cancers who could benefit from immunotherapy, the review says – and some new immunotherapy drugs have either not progressed from early phase trials or have failed in late-phase trials as they have been applied to unselected populations of less-immunogenic cancer types.

The secret to finding these patients could lie in creating better clinical trials.