One of the drawbacks of cancer therapies is that sometimes the cure itself also can damage the patient’s body. People are familiar with this scenario when they consider treatment options such as surgery, chemotherapy or radiation therapy.
This provides context for the recent announcement by some Toronto researchers of their work investigating CAR-T therapy for eliminating lung and blood cancers while avoiding a condition known as graft-versus-host disease.
How Does CAR-T Therapy Work?
In a laboratory setting, chimeric antigen receptor or CAR-T therapy is a tool that scientists are investigating to improve patients’ outcomes in cancer immunotherapy.
Chimeric antigen receptor therapy boosts the ability of the body’s T cells (that stands for “T lymphocytes”), to help a patient’s own immune system work more effectively against an invading cancer.
After doctors authorize CAR-T treatment for cancer patients, it’s time for technicians to extract T cells from the individuals’ blood samples. Then, it’s time to use CAR-T to modify the cells. The changed T cells must be reinfused into the patient’s body so they can start circulating through the blood system to identify cancer cells.
The enhanced T cells now have an ability to find a particular targeted antigen located on the cancer cells, to lock on and destroy them before they can grow more and potentially kill the patient.
Potential Role of CAR-T Therapy in New Cancer Treatments
Toronto researcher Li Zhang, M.D., Ph.D. has a lab where researchers are looking into off-the-shelf allogeneic CAR-T treatments. They want allogeneic solutions because today’s autologous cell treatments are complex and take a long time to produce, which isn’t ideal when you are dealing with the spread of cancer and do not want any delays.
Zhang and his colleagues have determined that double negative CAR-T cells, called DNTs are capable of removing lung and blood cancer tumors in a mouse model, yet without the unpleasant complicating factor of the host rejecting the graft.
Because the CAR-T cells under investigation are not able to express CD4 or CD8 proteins, they receive the name “double negative,” according to a report from Fierce Biotech, and they appear to be suitable alternatives in mouse cancer preliminary research that will eventually be applied to human cancers if work continues to go well in the Toronto laboratory.
The current research work is taking place as a follow-up to previous work that Zhang had conducted in China during the world’s first human phase 1 trial to test DNT CAR-T treatment on patients who had acute myeloid leukemia and who had experienced relapses after undergoing the aforementioned allogeneic stem cell treatments.
Then, of 10 patients, five died, and four stayed in remission for 16 months at a minimum. But the scientists saw that patients relapsed after stem cell infusions, and so they stopped giving them immunosuppresants. The idea is that in future experiments with CAR-T, Zhang and colleagues will be able to test the therapy without immunosuppression.
More Use of CAR-T Therapy on the Horizon?
With so much potential for scientists to harness CAR-T therapy in the field of cancer research, the developments in Toronto are worth keeping an eye on.
Remember that initial medical studies are done in steps far removed from actual work in living people. Scientists conduct computer modeling tests and make experiments in the lab with test tubes and other equipment before they expand their efforts with animals.
So after more mouse model experiments are conducted, with peer-reviewed journal reports to follow up to see if other researchers can replicate the results, scientists may get closer to using this in a widespread approach to treating cancer in humans with CAR-T therapy.