Critical study sheds light on deadly cancer
Patients suffering from acute lymphoblastic leukemia (ALL) may soon find relief thanks to modified T-cells in their immune system. So reveals a study published in the New England Journal of Medicine (NEJM) by a team lead by Dr. Carl June – an immunotherapist at the University of Pennsylvania – on Oct. 16.
The process involved modifying normal, healthy T-cells to attack patients’ leukemia. Once the T-cells were infused with a CTL019 antigen receptor that targeted the CD19 molecule found on the surface of cancerous B-cells, the T-cells were injected back into patients’ veins to carry out their mission.
B- and T-cells are lymphocytes part of the immune system. T-cells are responsible for destroying foreign bodies, while B-cells are responsible for storing information on foreign bodies to produce antigens for future encounters. Whereas T-cells are like soldiers, attempting to eliminate all foreign intruders, B-cells take a more methodical approach ensuring that the body is protected in the future.
Of the 30 children and adults who received the CTL019-infused T-cells, complete remission was achieved in 27 patients. This included 15 patients who had already undergone stem cell transplantation. Especially exciting is that sustained remission was achieved with a six-month event-free survival rate of 67 per cent, an overall survival rate of 78 per cent, and a 73 per cent chance of avoiding relapse at six months.
“Chimeric antigen receptor modified T-cell therapy against CD19 was effective in treating relapsed and refractory ALL,” concluded the study published in the NEJM. “CTL019 was associated with a high remission rate, even among patients for whom stem-cell transplantation had failed, and durable remissions up to 24 months were observed.”
Researchers pointed out that all of the patients had already undergone extensive therapy, and had failed conventional treatments.
“Initially, we didn’t know if we were just lucky with the first patients,” explained June in an excerpt from the The Verge.
However, June and his team are quick to explain that this is not a perfect solution for ALL. The modified T-cells target anything with the CD19 molecule; because all B-cells contain a CD19 molecule on their surface, this means that the modified cells destroy all of the body’s B-cells, cancerous or otherwise.
As a result, patients receive immunoglobulin replacements to boost their immune systems to normal levels.
Like all forms of leukemia, ALL is the cancer of white blood cells. ALL results in an overproduction of lymphoblasts – immature white blood cells – which prevents the production of normal cells like mature red and white blood cells, as well as platelets. The “acute” in ALL refers to the relatively short time it takes to differentiate it from chronic lymphocytic leukemia (CLL).
Unlike CLL, which is a disease that is most often diagnosed in adults, ALL is most common in children aged two- to five-years-old.
ALL is normally treated with a bone marrow transplant, but according to June, the side effects of this kind of treatment can be disastrous. June’s therapy avoids conventional treatment by utilizing patients’ own cells for treatment.