Cancer is the world’s second-biggest killer. The disease is responsible for around one in six deaths globally; 9.6 million people succumbed to it in 2018, while 18.1 million new cases were diagnosed. In 2025 there will be more than 20 million new cases, according to the World Health Organisation’s International Agency for Research on Cancer, and 29.5 million in 2040. To reduce cancer deaths we need new treatments beyond the conventional options of surgery, radiotherapy, chemotherapy and drugs discovered years ago. Fortunately, the last few years have seen a breakthrough in cancer treatments as a new field of research has developed: immunotherapy.
A new approach
Cancer immunotherapy is a new method of fighting cancer that uses the body’s own immune system to kill cancer cells where they are growing. This doesn’t happen naturally. The immune system is wired to conduct safety checks that prevent it attacking normal body cells. Cancer cells cleverly use these checks to fool the immune system into thinking tumour cells are just like normal cells – in other words, the cancer cells make themselves invisible to the body’s T-cells (white cells tasked to deal with disease carriers). That means T-cells cannot recognise cancer cells and therefore cannot attack them. The techniques of immunotherapy are all based on various ways of removing this cloak of invisibility from cancer cells and helping the immune system work better at destroying them.
The first immunotherapy drug to consistently improve survival, Yervoy (from Bristol-Myers Squibb), was approved in 2010 for treating metastatic melanoma (one that has spread to other parts of the body) and there are now at least ten immunotherapies approved for treating cancer with several approved for many different cancers. The fast pace of research is clear from the 2,000 or so ongoing clinical trials of new immunotherapy drugs. That will drive growth of the global cancer immunotherapy market from $40bn in 2017 to $170bn by 2028.
Miraculous results with some cancers
Immunotherapy can have miraculous results for particular kinds of cancer. One famous case is Philadelphia’s Stefanie Joho. Her colon cancer was raging out of control, with a massive tumour appearing in her abdomen despite surgery and chemotherapy. Her oncologist said there were no more treatment options left. However, Stefanie’s sister Jess discovered a clinical trial at Johns Hopkins University and Stefanie joined it. It was a trial of Keytruda, a drug not then approved for colon cancer, but which had helped treat former president Jimmy Carter’s brain and liver cancer. The results on Stefanie were remarkable: her tumour shrank and then disappeared, leaving her free from all signs of cancer. Further investigation showed that Stefanie had a genetic glitch called MMR deficiency; her cancer had many more mutations than usual and it was therefore more likely her immune system would recognise it and attack it with the assistance of Keytruda. In 2017, America’s Food and Drug Administration (FDA) approved Keytruda to treat colon cancers of Stefanie’s type. There are many similar stories of patients with advanced cancer whose lives have been saved by immunotherapy drugs.
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