Immunotherapy and cancer treatment
The power of the immune system can play a vital role in the development of new cancer treatments. Professor Stuart Tangye from the Garvan Institute explains.
What does ‘immunotherapy’ actually mean?
Immunotherapy simply refers to the ability to harness or manipulate the natural power and capacity of the immune system to improve the body’s response to infections or cancer.
Vaccination could be viewed as one early example of immunotherapy. This tricks the body into thinking we’ve already been infected by a particular microbe so that when we actually are exposed to this bacteria or virus, our immune system is fully armed and ready to fight it.
What role can harnessing our immune system have in fighting cancer?¨
There has been a long history of experimental science suggesting an important role for the immune system in protecting us against some types of cancer. There has also been some skepticism about this possibility! But now, clinical trials using drugs called ‘check point inhibitors’ have finally confirmed the critical function of our immune system in the process of tumour surveillance.
It is now known and accepted that mechanisms normally exist to restrain the function of immune cells. This typically happens at the end of an infection, or can be caused by cancer cells themselves. They act as something like a handbrake – they slow the cells down, keep them in check but stop them from functioning.
Check point inhibitors essentially release this hand brake, thereby allowing these immune cells to be completely functional again. And in the setting of some malignancies, the destructive power of these immune cells can be focused on cancer cells, thereby destroying them.
"Now we are seeing the use of a new class of drugs, which target our immune cells to fire up their function, rather than non-specifically targeting the cancer itself."
How does our knowledge about cancer today differ from what we knew a decade or two ago?¨
In the past, and still today to some extent, cancer was treated with chemotherapies that generally kill cells that undergo a lot of cell divisions.
While this targets cancer cells, it also targets many normal cells that also proliferate a lot – such as cells that line our stomachs, or hair follicles. So these cells are killed off as well. That's why people who are treated with chemotherapy develop nausea and lose their hair (to mention a few of many possible side effects).
Now we are seeing the use of a new class of drugs, which target our immune cells to fire up their function, rather than non-specifically targeting the cancer itself.
Immunotherapy has had a lot of success in treating melanoma and some types of lung cancer, and I think it will open up avenues for treating many different types of cancers – perhaps even those where we didn’t consider the immune system to have much of a role.
What role is the Garvan Institute playing in driving research in this area?
There is some really excellent research going on at Garvan that addresses the role of the immune system in both preventing and contributing to the development of different types of cancers – such as breast cancer, melanoma, lymphoma and sarcoma.
Garvan has significant strength in researching both cancer and immunology, so it is only natural that both of these divisions are in regular discussion and collaboration.
This enables us to make those breakthroughs and improve our understanding of mechanisms that cause and prevent cancer, and how these can be exploited or circumvented to develop new therapies for patient treatment and management.