You may have hear about the recent approval by the Food and Drug Administration (FDA) of the first gene therapy treatment in the United States. It’s now available to treat some pediatric patients with acute lymphoblastic leukemia (ALL).
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ALL is a blood and bone marrow cancer in children. It causes immature white blood cells to grow out of control. This condition progresses quickly and can be fatal within months if left untreated.
ALL is the most common childhood cancer in the United States, and affects up to 5,000 children each year.
The new treatment, called tisagenlecleucel and sold under the brand name Kymriah™, can treat patients up to age 25 who have not responded to initial chemotherapy or who have had a relapse after treatment. This occurs in up to 20 percent of those with ALL. Until now, there have been few treatment options for these patients.
The FDA approval applies to a fairly small group of patients. But oncologists view it as an important beginning.
“This therapy is truly remarkable,” says oncologist Mikkael Sekeres, MD. “This is a vanguard of cancer therapy that we’re going to see more and more of in the future.”
How does this therapy work?
Kymriah™ is an immunotherapy treatment that focuses on patients whose ALL affects B-cells, a type of white blood cell.
The therapy works by genetically modifying immune cells collected from a patient’s blood, adding a gene with a protein called chimeric antigen receptor (CAR).
The treatment team then returns the modified blood to the patient to do its job of finding and destroying leukemia cells..
“This is a paradigm shift, a real step forward in personalized treatments for cancer,” Dr. Sekeres says. Physicians, he says, “are very hopeful that this is just the beginning.”
Trial sees impressive success rates
The treatment’s clinical trial was a small one, with only 63 pediatric patients. But the results were impressive: Within three months of treatment, patients had an overall remission rate of 83 percent, Dr. Sekeres says.
The follow-up on patients was short — only about five months after treatment. The drugmaker, Novartis, is continuing with a long-term observational study of the participants. Doctors consider ALL cured when patients are free of the condition for four years after treatment ends.
What are potential side effects?
Though Kymriah™ appears to be highly effective, it comes with potential serious side effects, Dr. Sekeres says.
It can cause a condition called cytokine release syndrome (CRS), which produces high fever and flu-like symptoms. CRS is sometimes life-threatening.
In response, the FDA has expanded the use of tocilizumab, which is sold under the brand name Actemra® to treat CRS in children ages 2 and older. Studies show that Actemra® can eliminate CRS within two weeks for many patients.
Kymriah™ can also cause potentially life-threatening neurological problems. More minor side effects, which may occur within a month of treatment, include:
- Low blood pressure
- Kidney damage
- Decreased oxygen levels
Gene therapy like Kymriah™, which uses a person’s own cells to fight cancer, is a new and promising approach to ALL, Dr. Sekeres says. It holds promise for many other challenging health conditions as well. Your child’s pediatrician can help you determine whether he or she is a candidate for the therapy.