How CAR T-Cell Therapy Affects the Body
- CAR T-cell therapy is a treatment for some people with non-Hodgkin lymphoma that hasn’t responded or has come back after other therapies
- The CAR T cells can produce inflammation that causes a fever, low blood pressure, and other symptoms
- This treatment can also affect the brain, leading to headache, confusion, and difficulty talking
“CAR T-cell therapy has some toxicities and downsides,” Dr. Michael Jain, medical oncologist at Moffitt Cancer Center, tells SurvivorNet.
Read MoreA Flood of Cytokines
Once the CAR T cells are infused into someone’s body, they multiply over the first week. While the CAR T cells are killing cancer cells, they also produce inflammation and a collection of symptoms known as cytokine release syndrome.One of the main symptoms is a fever, which can spike as high as 104 degrees Fahrenheit. Some people will develop more serious symptoms such as low blood pressure, difficulty breathing, or damage to organs such as their heart, lungs, kidneys, or liver.
The good news is, cytokine release syndrome is usually short-lived, Dr. Jain says. “Once the cells have increased to the number they are going to peak at, the number starts to go down and the cytokine release syndrome goes away.”
Doctors will monitor a person’s vital signs, such as their temperature, breathing, blood pressure, oxygen levels, and heart rate, very carefully during cytokine release syndrome. Treatment often involves supportive care such as oxygen, blood pressure medicines, and IV fluids in a hospital. Those with severe cytokine release syndrome may get drugs to bring down inflammation, such as corticosteroids or immune-suppressing medications.
Fortunately, now doctors are better equipped to manage the response to CAR T-cell therapy, so the rate of severe cytokine release syndrome is only around 7%, Dr. Jain says. “It’s really a minority of patients who are going to have significant amounts of the cytokine release syndrome, although almost every patient will get a fever.”
Mental Fog
More concerning is a side effect that doctors call neurological toxicity, or neurotoxicity. The process of the CAR T cells multiplying activates certain immune cells that lead to damage in the brain known as encephalopathy.
Symptoms usually start gradually. At first, someone with this condition might struggle with what was previously a simple task, such as switching on the TV or changing the channel with the remote control. “But it may progress to the point where patients have difficulty talking and seem extremely confused,” Dr. Jain says.
Other symptoms of neurotoxicity include:
- Headache
- Confusion
- Weakness
- Mental changes
- Seizures
- Difficulty balancing
- Trouble talking
About 30% of patients are not able to talk at all, says Dr. Jain. “We call that severe neurological toxicity, and it may progress, even in very rare cases to patients needing to go onto a ventilator because they have trouble protecting themselves from swallowing their saliva and getting pneumonia.”
Fortunately, because these symptoms are all a direct response to the CAR T cells, the condition shouldn’t last for more than a few weeks. “When we looked out to 90 days, three months after the CAR T-cell therapy, almost everyone was back to normal, reported very few symptoms and in some cases, were even better than they were before the therapy because their lymphoma was under better control,” he adds.
Although many side effects of CAR T-cell therapy are short-lived, some can persist. If your symptoms continue weeks after you finish treatment, talk with your doctor about next steps.
Reviewed by Dr. Sairah Ahmed, associate professor, Department of Lymphoma/Myeloma, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center
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