What’s the Real CAR-T Therapy Success Rate for Cancer?
Scott McIntyre became one of the first people treated with CAR-T therapy in the state of Illinois, back in 2016. When he was first diagnosed with diffuse large B-cell lymphoma (DLBCL), he was told he had just a few months to live. McIntyre received a stem cell transplant, multiple rounds of chemotherapy, radiation therapy and multiple clinical trials. Nothing worked.
After the lymphoma spread to his lungs, McIntyre heard about the promising immunotherapy treatment that utilizes chimeric antigen receptor T-cells (CAR-T). He signed up for a trial at the University of Chicago Medicine, and six years after receiving CAR-T therapy, he’s still alive and cancer free. It’s success stories like these about CAR-T therapy that make this one of the most sought-after cancer treatments by patients worldwide. But how successful is it really?
CAR-T therapy begins with the harvesting of white blood cells from a cancer patient. The T-cells are separated out, so that they can be altered at a genetic level to fight cancer cells. Once this genetic engineering process is complete, the patient’s T-cells are readministered to them in a process that takes about 10 minutes. The modified T-cells have now been reprogrammed to target and kill cancer cells within the body, based on specific genetic antigen receptors on these cells.
In Scott McIntyre’s case, he ran a fever for a few weeks after CAR-T therapy, which most patients do. But then he gradually started feeling better. When a doctor from UC Medicine called to update him on his latest bone marrow biopsy, he was informed that the cancer was gone. Other than the initial fever, McIntyre has never had any other side effects from his treatment. He still needs an immunoglobin infusion at the doctor’s office every few months, which helps his immune system to fight off infections, but that’s the only ongoing treatment he receives.
McIntyre’s doctor at UChicago Medicine was oncologist and researcher Sonali Smith, MD. McIntyre has been a lifelong fan of Notre Dame football, and the first year that he was cancer-free, he texted Smith a photo of himself and his family at a Notre Dame game. He texted her, “Because of you, I’m living my dream.” The annual “selfie” sent to Dr. Smith from a Notre Dame football game has continued every year since then.
But not all patients experience the same level of success as Scott McIntyre. The Director of UChicago Medicine’s cellular therapy program, Dr. Michael Bishop, estimates that the success rate of CAR-T therapy is somewhere between 30 and 40 percent of patients. While that means that CAR-T therapy is unsuccessful in more than half of patients, it is still one of the most promising cancer treatments to be developed in years. When clinical trials for CAR-T therapy are announced, they immediately fill up with cancer patients.
To date, five separate CAR-T therapy drugs have been approved for use by the US Food and Drug Administration (FDA). Two serious side effects associated with the treatment are cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome. Because of these possible effects, a patient must have undergone at least one prior type of cancer treatment that was unsuccessful before attempting CAR-T therapy.
This innovative treatment is allowed for diffuse large B-cell lymphoma (DLBCL), B-cell acute lymphoblastic leukemia (ALL), follicular lymphoma, multiple myeloma and mantle myeloma. Clinical trials are under way to improve the efficacy of CAR-T therapy, and to find new treatment methods for additional types of cancer.