CAR T-cell therapy changes your immune cells to help them hunt down and kill cancer cells in your body. It’s been approved to treat two types of cancer: B-cell precursor acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma.
CAR T-cell therapy may work when other treatments haven’t. In some people, it can get rid of all signs of cancer. This is called remission. But it also has side effects, and some of them can be serious. Your doctor can help you decide if it’s right for you.
Benefits of CAR T-Cell Therapy
The immune cells this treatment uses are called T cells. Each one that's changed and put in your body can multiply into thousands of new ones.
"Part of the magic of this therapy is that it not only signals the T cell to kill the tumor, it also signals the T cell to grow and divide," says David Porter, MD, the Jodi Fisher Horowitz Professor in Leukemia Care Excellence and director of blood and marrow transplantation at the Hospital of the University of Pennsylvania.
After one treatment, those cells stay in your body and keep killing cancer cells. That's why CAR T-cell therapy is called a "living drug."
"It can have long-lasting activity over many months or years," Porter says. "And because of that, it has the ability to work where standard, conventional treatment fails."
In one study of children with ALL that came back after treatment, 83% went into remission on CAR T-cell therapy. Only 25% to 50% of children who have ALL that has returned go into remission with chemotherapy and other standard treatments.
In some cases, remission from CAR T-cell therapy has lasted years.
Side Effects of CAR T-Cell Therapy
Cancer treatments like chemotherapy and radiation kill both cancer cells and healthy cells, which is why they can cause things like nausea, vomiting, and infections. Because CAR T-cell therapy targets only cancer cells, it doesn’t lead to those. But it can cause a few other health issues.
Cytokine release syndrome (CRS)
One of the main side effects of CAR T-cell therapy is also a sign that the treatment is working. As the cells grow and divide in your body, they make chemical messengers called cytokines that help launch the immune system’s attack against the cancer cells.
"The cytokines are necessary to kill tumor cells, but they also cause some of the side effects," explains Sattva Neelapu, MD, professor and deputy chair in the department of lymphoma/myeloma at the University of Texas M.D. Anderson Cancer Center.
This flood of cytokines into your blood causes a condition called cytokine release syndrome (CRS), or cytokine storm. It can bring on flu-like symptoms, such as:
- High fever
- Body aches
These symptoms typically start the first few days after treatment. They’re usually mild enough to manage with over-the-counter pain relievers and extra fluids and go away within 1 to 2 weeks.
Less often, people with CRS have more serious side effects, such as:
- Low blood pressure
- Fast heart rate (tachycardia)
- Irregular heart rhythm
- Heart failure
- Low oxygen in the blood
Medicines like steroids and tocilizumab (Actemra) can help with these symptoms, but a small number of people need to be treated in the hospital.
CAR T-cell therapy targets a protein called CD19 on the surface of cancer cells. This protein is also on the surface of B cells, which are immune cells that make the antibodies your body needs to fight off infections.
"One of the side effects is that patients lose their B cells. They lose their ability to make antibodies," Porter says. "One of the long-term risks we worry about is the risk of infection."
Doctors treat this side effect with immunoglobulin (IVIG) therapy, which replaces the antibodies you lose.
CAR-T-cell-related encephalopathy syndrome (CRES)
Sometimes CAR T-cell therapy can affect your brain and cause symptoms like:
- Trouble speaking
- Loss of balance
Doctors don't know what causes CRES, but it doesn’t typically last. "Very often, people just get better on their own," Porter says.
In very rare cases, it can lead to swelling in the brain.
Watching for Side Effects
Your doctor will want to keep a close eye on you while you’re getting CAR T-cell therapy. Many cancer centers ask people to stay close to the hospital for several weeks in case they need medical care right away.
But most side effects should be short-lived. "With chemotherapy, the side effects last much longer because it's given in cycles," Neelapu says. "CAR T-cell therapy is a one-time infusion. The side effects are all short-term. They happen in the first 1 to 2 weeks, and then they're done."