July 10, 2017 | by Stephanie Smith
When viewed under a microscope, T cells — sentinels of the immune system whose job inside the body is to seek out foreign invaders — quiver as they surround and consume cancer cells.
“Soldiers of the immune system,” is how Christine Brown, Ph.D., Heritage Provider Network Professor in Immunotherapy at City of Hope, describes them. “They’re white blood cells whose normal job is to eradicate unwanted cells.”
But the T cells Brown is describing are not normal. They were genetically modified in a lab by City of Hope researchers and trained to target specific receptors on patients’ brain tumors — part of an emerging approach to cancer care called immunotherapy.
“We’re engineering the immune system to recognize and actually destroy a patient’s tumor,” said Brown, associate director of the T Cell Therapeutics Research Laboratory at City of Hope. “It’s a really exciting new approach to cancer therapy.”
Here is a glimpse of how that “engineering” process works:
Step 1: T cells are isolated from the patient by way of a specialized blood draw.
Step 2: The T cells are then reprogrammed (in a process involving the use of a harmless virus) to produce special receptors on their surface called chimeric antigen receptors, or CARs. This enables the T cells to better recognize tumor cells.
Step 3: The engineered CAR T cells are then grown in the laboratory until they number in the billions.
Step 4: CAR T cells are infused back into the patient.
Step 5: They multiply inside the patient’s body and, with guidance from their engineered receptors, are able to recognize and then kill cancer cells.
In a case study published recently in the New England Journal of Medicine, Brown and colleagues — including Behnam Badie, M.D., chief of the Division of Neurosurgery and director of the Brain Tumor Program, and Stephen J. Forman, M.D., the Francis & Kathleen McNamara Distinguished Chair in Hematology and Hematopoietic Cell Transplantation — describe promising results for a patient with an aggressive brain cancer, multifocal glioblastoma, who was treated with his own genetically modified CAR T cells.
It is one case among many being undertaken at City of Hope, whose programs in CAR T cell therapy are being used to treat blood cancers such as leukemia, lymphoma and multiple myeloma, and solid tumors including prostate and brain cancer.
For more information about the brain CAR T program, please visit www.cityofhope.org/brain-car t-cell.