By Jana Soeldner Danger
City & Shore Magazine
A recently approved type of immunotherapy is offering new hope and help for some leukemia and lymphoma patients for whom other treatments have failed. The new CAR T cell therapy strengthens and mobilizes the patient’s own immune system to fight these life-threatening cancers, says Dr. Krishna Komanduri, professor of medicine, microbiology & immunology and director of the adult stem-cell transplant program at the University of Miami Sylvester Cancer Center. “It’s really an evolutionary leap,” he says. “It represents a completely different paradigm for fighting these diseases.”
Sylvester conducted clinical trials for the new therapy and is one of fewer than 20 centers around the country offering it. It is currently the only center in South Florida.
Here’s how it works: An antigen called CD19 occurs on the surface of B-lymphocytes, a kind of white blood cell. The uncontrolled proliferation of cancer cells that also have CD19 on their surfaces results in leukemia and lymphoma. The new therapy mobilizes the body’s T cells, which play an important role in the body’s general immune response, to search out B cells and kill them.
How it begins
The process begins with removing a broad range of healthy T cells from the patient, Dr. Komanduri says. They are then sent to a central laboratory where they are genetically modified to express a new receptor called a Chimeric Antigen Receptor (CAR).
The number of genetically modified T cells, which now express the CAR that recognizes and targets the CD19 antigen on both cancer cells and healthy B cells, is expanded in the laboratory until there are millions of them, a process that takes about two weeks, Dr. Komanduri says. They are then sent back to the clinic treating the patient.
Next, the patient receives a dose of chemotherapy to destroy cells that would otherwise compete with further expansion of the genetically modified T cells. Then the T cells are reintroduced into the patient’s bloodstream, where their engineered receptors allow them to recognize, pursue and kill cancer cells with the CD19 antigen. “It’s like giving the patient a living drug,” Dr. Komanduri says.
The therapy is not without side effects. In addition to destroying cancerous B cells, it also kills healthy ones. When the T cells multiply, it can also cause inflammation and possible neurological symptoms, Dr. Komanduri says. But while the side effects can be serious, they are most often manageable.
The new therapy is used in patients for whom at least two prior courses of treatment have failed. With current treatments, only 20 to 30 percent of these individuals would respond to additional chemotherapy, and less than 10 percent would have a complete remission.
Dramatically different results
Results for the CAR T therapy are dramatically different. In clinical trials, 80 percent of patients responded favorably, and more than 45 percent had a complete remission. Because the treatment is so new, patients have been tracked for a relatively short time. But many remain in remission, results that are much different than would have been expected for a patient population that had failed chemotherapy, Dr. Komanduri says.
The therapy is one more weapon in the arsenal for fighting blood cancers, and for some patients, it brings the possibility of living longer and even a possible cure. “I’ve had personal experiences with patients who have had dramatic responses to CAR T cell therapy,” Dr. Komanduri says. “They might otherwise not have been expected to live.”