Dr. Doug Mahoney’s lab is one of three in the world looking at a new immunotherapy combination that is showing promise for killing cancer.

Immunotherapy is a promising new arena in the global fight against cancer, where scientists and clinicians search for ways to harness the body’s own immune system to attack and kill cancer. Thanks to your support, a Calgary research team has made an important discovery in immunotherapy that uses existing drugs in a whole new way.

“What we found is a combination of cancer therapies that complement each other to help the immune system clear the cancer,” says Dr. Doug Mahoney, a Kids Cancer Care-funded researcher at the University of Calgary’s Cumming School of Medicine and the Alberta Children’s Hospital Research Institute. “Our results suggest that we’ve been looking at these cancer drugs the wrong way — as tumour-targeting drugs — instead of what we now feel is their most important biological role: as immune stimulating therapy.”

Ramping up the immune system to kill cancer

Cancer cells are able to survive because they know how to hide from the body’s immune system. They also know how to control certain immune cells. Some cancerous tumours can reprogram immune cells to block other immune cells from attacking, leaving the tumour free to grow.

Treatments aimed at revving up the immune system’s attack on the cancer may be the most promising approach to cancer therapy since the evolution of combination chemotherapy. Research shows that single therapies, targeting only one part of the immune system, are effective in treating only a small percentage of patients. Results from Dr. Mahoney’s research are consistent with other recent findings, which suggest that smart combinations of therapies are even more effective in battling some cancers.

A two-pronged approach

In Dr. Mahoney’s study, researchers combined two therapies, each targeting a different part of the immune system. The first one boosts the immune system, followed by a second one, which stops the tumour from reprogramming immune cells.

“This combination of drugs allowed the immune cells to do what they’re supposed to do,” says Dr. Mahoney. “We were able to cure cancer in 20 to 60 per cent of our animal models. It’s a very promising result against two very deadly forms of cancer: an aggressive breast cancer and a rare pediatric muscle cancer.”

When the researchers added a third complementary immunotherapy, the cure rate went as high as 80 to 100 per cent. Results of the study are published in Nature Communications.

Drugs seen in a new light

“These results change a lot,” says Dr. Mahoney. “What’s interesting is that neither drug was developed as an immunotherapy. For nearly two decades they have been studied for their ability to directly kill cancer cells. Viewing these drugs through the lens of immunotherapy, will impact the way we study them and try to figure out how to make them work better. From a clinical perspective, it changes the way we will try to translate these drugs.”

Mahoney says we’ll know more about the impact this study will have on cancer patients in the next five years. His lab is one of three in the world looking at this immunotherapy combination. In the other two locations, clinical trials are about to start based on a similar results.

This research study was supported by the Canadian Cancer Society, the Alliance for Cancer Gene Therapy, and the Cancer Research Society. Doug Mahoney’s lab, the Trican Childhood Cancer Therapeutics Lab, is supported by Trican Well Service, Kids Cancer Care Foundation of Alberta, Alberta Children’s Hospital Foundation and Believe in the Gold Foundation.

Dr. Doug Mahoney (PhD) is an assistant professor in the Departments of Microbiology, Immunology and Infectious Diseases; and Biochemistry and Molecular Biology at the University of Calgary Cumming School of Medicine, a member of Arnie Charbonneau Cancer and Alberta Children’s Hospital Research Institutes and a member of the Experimental and Applied Therapeutics research effort at the Childhood Cancer Research Program.

~ Revised with permission from the University of Calgary’s Cumming School of Medicine