A new approach to immunotherapy developed by researchers at the National Cancer Institute (NCI), the US, has led to the complete regression of breast cancer in a patient with advanced metastatic cancer, who was previously unresponsive to all other treatments and was given just months to live.

The new immunotherapy approach is a modified form of adoptive cell transfer (ACT). ACT has been effective in treating melanoma, which has high levels of somatic mutations. The treatment works by targeting genetic mutations that are acquired by cancer cells as they grow and multiply. These mutations are different in each patient, and some bring in modifications to the proteins that sit on the cell surface. These surface proteins can be identified well by the immune system, prompting it to attack the cancer cells.

The findings in this particular woman’s case show how naturally-occurring tumour infiltrating lymphocytes (TILs) were extracted from the patient’s tumour, grown outside of her body to grow their numbers and injected back into the patient’s body to handle the cancer cells. The patient had previously received several treatments including hormone therapies and chemotherapy, but the cancer still progressed. After this new treatment, all the tumours disappeared and 22 months later, she is still in remission!

Researchers are now enthusiastic about the potential of these TILs to similarly treat a whole group of cancers called ‘common epithelial cancers’ – colon, rectum, pancreas, breasts and lungs, together accounting for 90% of all deaths due to cancer in the U.S, around 540,000 people annually.

“I think it’s an extremely exciting and promising strategy”, says Charles Swanton of the Francis Crick Institute, London.

These results are also very promising when considering the low levels of toxicity, the patient experienced compared to chemotherapy treatment. Now, what is immediately required is for the results to be tested on larger scale clinical trials, that are already underway. The team is also working on improving their methods for multiple steps of the treatment.

References:

1. New immunotherapy treatment removes all tumors in woman with advanced metastatic breast cancer, June 2018, Forbes.
2. New approach to immunotherapy leads to complete response in breast cancer patient unresponsive to other treatments, June 2018, National Institutes of Health.
3. Woman survives metastatic breast cancer thanks to new treatment, June 2018, NewScientist.