Published on
Updated
Reading 2 mins.
Gene-editing technology CRISPR could be a new form of cancer treatment, according to a new study. However, this would involve risks according to Dr Ivan Pourmir, oncologist and researcher in immunotherapy at the European Georges-Pompidou Hospital.
For the first time, scientists have used CRISPR technology to increase the levels of T cells inside the body, allowing them to destroy the cells responsible for cancer. The results of this new study, carried out by researchers at PACT Pharma, are available in the journal Nature.
modified immune cells
This isn’t the first time the CRISPR technique has been used in humans to knock out specific genes – it’s already been used in blood cancer treatments. But the novelty of this early trial concerns the modification of certain immune cells in the context of targeted cancers: colon, breast, lung…
“In France, this practice is called adoptive therapy. The principle is to add a receptor to the surface of cancer cells to allow blood cells to destroy them.“, confides Dr. Pourmir. “But the big difference between hematological cancers and those targeted is that, in the second category of cancer, the cells are very different from each other and express the antigens differently. It is therefore very difficult to modify each white blood cell, of each patient“.
Once reintroduced into the patient’s body, the modified cells naturally move towards the tumor and take over from the T lymphocytes to destroy the cancerous cells.
“This is a leap forward in the development of personalized cancer treatment, where the isolation of immune receptors that specifically recognize mutations in the patient’s own cancer are used to treat the tumor“, says Dr. Ribas, corresponding author of the article.
However, this experimental technique has only been tested in 16 patients – with colon, breast or lung cancer and whose previous treatments had ended in failure.
The volunteers received modified T cell receptors and benefited, in parallel, from conditioning chemotherapy. A total of 37 T cell receptors were transfused through blood.
Each patient also had to take a drug to reduce the number of immune cells produced, so that the modified ones replaced them.
Results ? Out of 16 patients, 5 of them saw their condition improve and stabilize after only one month of treatment.
The number of modified immune cells navigating close to the tumors was also significantly higher than that of the unmodified cells.
CRISPRP technology: an expensive and cumbersome therapy
Results that are not enough to convince Dr. Pourmir, who judges the therapy “very sophisticated, but also very long and very heavy.”
“The participants’ cancer grew despite the treatment. At best, it remained stable. It is therefore questionable whether the therapy really had any positive effects on the patients or whether it is simply a natural evolution of the cancer..”
In addition, CRISPR therapy triggered a severe immune reaction (encephalitis) in one of the patients. His immune system attacked his brain.
Finally, any modification of the white blood cells can induce cancerization.
“ We must therefore be very careful about the safety of this long-term treatment.“, concludes Dr. Pourmir.