Immunotherapy has been in the science and health news a lot recently, but it is not a new treatment for cancer. Immunotherapy drugs work by stimulating the immune system to recognise and fight cancer and is already being used to tackle certain cancers. However, the response rate is still relatively low, and is a treatment that is in constant development and trials to improve its use.
New trials in using immunotherapy for more complicated cancer diagnoses are proving to be successful. One trial has shown that immunotherapy treatment could halt the spread of otherwise untreatable prostate cancer, as after one year over a third of the men participating were still alive, and one-in-ten had not had any further cancer growth one year on. Previous trials using immunotherapy for prostate cancer patients were unsuccessful, but recent research has examined the genetics of tumours and found how particular groups of patients may benefit. It is the first time immunotherapy has been shown to benefit some men with prostate cancer, the researchers said.
All the men on this trial were given the drug pembrolizumab, which is an immune checkpoint inhibitor. Checkpoints are used by cells to protect against immune attack, but cancer cells can use this to evade the immune system, causing cancer cells to spread. Checkpoint inhibitors allow the immune system to go around this system and hone in on cancer cells and attack them. The drawback to this is the immune system could get overactivated and attack normal, healthy cells but this only occurs in a minority of patients. A report presented at the 2018 meeting of the American Society of Clinical Oncology also identified that patients with non-small cell lung cancer who were given pembrolizumab alongside chemotherapy had a reduced risk of death by 36%.
Another case which has been circulating the media is of Judy Perkins, a woman in Florida who has been successfully treated of her advanced metastatic breast cancer after doctors tweaked her immune system to enable it to destroy the tumours that had spread through her body. Judy had already recovered from a malignant tumour only for her cancer to return more aggressively 10 years later, which is fairly common with breast cancer. Several chemotherapy sessions had failed to kill her cancer, and she was given three years to live.
Immunotherapy was previously thought to be ‘off-limits’ for her type of cancer, but a form of personalised treatment proved otherwise. This tailored treatment consisted of extracting T-cells from within the tumours. These cells try to identify and destroy cancerous cells but are ineffective on their own as the cancerous cells can evade their checkpoints. Researchers sequenced DNA and RNA from one of her tumours and from some of her normal tissue to see which mutated proteins were made by cancerous cells but not by healthy cells. They then programmed the T-cells to target the mutations and infused large cultures of them back in Judy’s immune system.
For the first time, this process was administered alongside pembrolizumab. Judy has now remained cancer-free for three years, and unprecedented outcome for such advanced breast cancer. This new approach to immunotherapy is dependent on mutations and not on cancer type, so it is more of a blueprint that can hopefully be used to treat other types of cancer. It is still in the experimental stages, but cancer specialists are hopeful this new approach to immunotherapy could succeed where others have failed.