CAR-T Cancer Therapy: Supercharging a Patient’s Own Cells to Battle Cancer
CAR-T Cancer Therapy: Supercharging a Patient’s Own Cells to Battle Cancer
The U.S. Food and Drug Administration has approved a novel cancer treatment that resulted in 83% of patients with resistant leukemia going into remission, and the majority remaining cancer free after a year. The treatment is called CAR-T therapy, and it uses a patient’s own white blood cells that have been genetically re-engineered to specifically target and kill cancer cells. The freshly licensed therapy, called Kymriah, is produced by Novartis and has been approved to treat children and youthful adults with relapsed acute lymphoblastic leukemia.
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Alexis Bonilla participated in the Novartis CAR-T trial and has now been leukemia-free for almost twenty months. (Photo: Business Wire)
“Despite the almost continuous advances that have been made in the treatment of leukemia, this malignancy remains a leading cause of death in childhood,” says Alan Wayne, MD, director of the Children’s Center for Cancer and Blood Diseases at Children’s Hospital Los Angeles and professor of Pediatrics and Medicine at the Keck School of Medicine of the University of Southern California. “At CHLA, we can now suggest potent immunotherapies, like CAR-T, to children with the most resistant cancers.”
Children’s Hospital Los Angeles was one of a petite number of sites that participated in the trial that led the FDA to approve Kymriah, and it is one of thirty two hospitals in the U.S. that have been approved to treat patients with this therapy.
At CHLA, the Novartis CAR-T trial is being led by Michael Pulsipher, MD, section head of Blood and Marrow Transplantation. He and Wayne are leading a number of other CAR-T studies to determine the effectiveness of the treatment in different types of patients.
Treatment with CAR-T
Ninety percent of children diagnosed with acute lymphoblastic leukemia are cured. However, of those who relapse, only a minority sustain long-term. So when Alexis Bonilla was eleven years old and his disease returned for the third time, his doctor instantly referred him to CHLA.
“I told Alexis’ parents that the good news is we have a fresh therapy, and after being treated with it, your son has almost a ninety percent chance of remission,” says Pulsipher. “The not-so-good news is that it might primarily make him very sick.” Pulsipher told the duo about a clinical trial for chimeric antigen receptor T cell (CAR-T) therapy.
Alexis’ mom, Daysi Bonilla, and his stepdad, Jorge, agreed right away to have their son in the probe.
T cells are a type of white blood cell that is part of our defense against viruses, bacteria and to a lesser extent, cancer. CAR-T therapy harnesses the immune system by engineering the T cells to specifically attack cancer cells. The opposite of a “one size fits all” strategy, this treatment is individually created for each patient using his or her own cells.
A sample of Alexis’ blood was taken and sent to the lab so that his T cells could be genetically engineered to produce a chimeric antigen receptor (CAR) on their surface. The receptor directs the T cells to a protein, called CD19, present on leukemia cells. When the CAR-T cell connects with the CD19 protein, the leukemia cell is ruined.
Alexis received several weeks of high-dose chemotherapy to kill as many leukemia cells as possible. Then his modified T cells were re-infused.
Waiting to see what happens
“Ninety percent of patients develop a fever after the cells are infused,” says Pulsipher. “It’s a side effect that we want to see because it indicates that the CAR-T cells are functioning appropriately.”
He explains that the greater number of tumor cells a patient has, the greater their immune response. Sometimes, the battle inbetween the supercharged T cells and the large number of cancer cells becomes extreme, causing the patient’s blood pressure to plummet.
This reaction, known as cytokine release syndrome, or “cytokine storm,” occurred in Alexis. He was moved to the intensive care unit so that his response could be securely managed. “It was scary,” says Daysi.
What’s next for CAR-T?
When an experimental therapy is introduced into the clinic at the earliest stage of investigation, it is tested in people who have disease that is resistant to all other treatments—basically, the sickest patients.
“As we build up practice with CAR-T and trials are open to a broader multiplicity of patients, I anticipate that we will see less-severe side effects in people with earlier-stage disease,” says Pulsipher, who is also a professor of Pediatrics at the Keck School of Medicine of USC. Until then, he and his colleagues are glad to have this truly life-changing therapy to suggest their most gravely ill patients.
Alexis made a rapid recovery. Two months after embarking treatment at CHLA, he was ready to come back home. He always bounces back, Daysi says.
“He wants life,” adds Jorge.
Alexis has been in remission from leukemia for almost twenty months.