Immunotherapy is a new type of treatment for cancer that works by stimulating the body’s own immune system to fight cancer cells. This happens naturally, but once a cancer has taken hold the immune cannot cope any more and stops fighting the cancer. A series of drugs have been developed that use ‘checkpoint inhibitors’ which allow the body’s immune system to kick into action again and start fighting the cancer cells.
Unlike other treatments for cancer such as chemotherapy and radiation therapy, immunotherapy has a longer lasting effect and trials of the new treatment have seen around 60% of cases of advanced melanoma respond with tumours shrinking in size. The trial involved a combination of two drugs – Ipilimumab and Nivolumab – given to a group of 945 patients around the world, and 58% of these patients saw their tumours stop growing or shrink over just under a year.
Another benefit of the new treatment is fewer side effects than more conventional approaches, although some side effects have been reported, such as fatigue, rashes and diarrhoea, which affect 25% of patients being treated with one drug and half of all patients being treated with a combination of two drugs.
Although immunotherapy is showing great promise, at the moment the high cost of these drugs is a major drawback. A year’s supply of Ipilimumab, which needs to be injected into the bloodstream four times a year, costs nearly $200,000. And combinations of immunotherapy drugs, which can be more effective in some cases, of course will cost more.
Immunotherapy is currently used to treat both melanoma and lung cancers. Cancer Council of Australia statistics show that melanoma is the fourth most common cancer in Australia.