Two American patients with chronic lymphocytic leukemia received an innovative treatment using their own modified immune cells. The result is that 11 years later, both patients remain cancer-free after CAR T cell therapy.
Chronic lymphocytic leukemia is a blood cancer that primarily affects older people and accounts for about a quarter of new leukemia cases.
Reprogramming immune cells to eliminate cancer
The treatment involves extracting T cells, white blood cells that fight viruses, from a patient’s blood, and genetically modifying them to fight cancer. The modified cells are then re-infused into the patient’s circulation.
The result is that these cells manage to specifically attack the tumor, achieving, in some cases, its complete remission, as described by researchers from the University of Pennsylvania about the treatment immersed in their 10-year study called T-cell therapy with CAR, and published by the journal Nature.
experimental immunotherapy
While not everyone receiving this CAR-T cell treatment may have the same success, the results of this clinical trial of an experimental therapy can be considered a milestone in the field .
“We can now conclude that CAR T cells can cure leukemia patients,” explains Carl June of the University of Pennsylvania, who led the study.
Logically, the researchers do not know if the cancer will return to the patients at some point, but for the moment, they have been free of it for more than a decade. Since the start of the trial, more people have been treated, with an estimated 4 in 10 cancers going into remission .
What is special about CAR T cells?
CAR T cells are currently used for several types of blood cancers, such as leukemia and lymphomas, in patients who have not responded to other treatments . To do this, doctors take a blood sample and remove T cells, immune cells that normally attack tumor cells but have not been successful in people with cancer. The cells then have the gene for an artificial receptor added to their DNA by a virus, and are encouraged to multiply about 10 times. Weeks later, they are introduced back into the patient. These genetically modified cells track down and kill cancer cells.
A living drug that works against leukemia
Probably the only negative thing we can say about this medical milestone is that immunotherapy doesn’t work for everyone. Some people don’t respond to treatment, and other people can develop dangerous side effects (such as high fever, coma, dangerously low blood pressure, and even death). And it hasn’t yet worked with solid tumors in patients with breast or prostate cancer. Despite this, researchers are “starting to learn the mechanism of why and how it works, so we can start to learn how to make it work for more people,” said David Porter of the University of Pennsylvania and co-author of the paper.
Referencia: Melenhorst, J.J., Chen, G.M., Wang, M. et al. Decade-long leukaemia remissions with persistence of CD4+ CAR T cells. Nature (2022). DOI: https://doi.org/10.1038/s41586-021-04390-6
