What Is CAR T-Cell Therapy?

Medically Reviewed by Sabrina Felson, MD on February 22, 2024
5 min read

Chimeric antigen receptor (CAR) T-cell therapy is a kind of cancer treatment that uses cells from your own immune system. Doctors take a type of white blood cell from your body and genetically change the cells in a lab so they can better find your cancer. Then millions of these target-seeking cells are put back into your body.

The treatment is fairly new, so doctors don't know how well it works or how long it lasts. The price is also quite high, and some insurance companies haven't figured out how to pay for it.

You'll need to talk with your doctor about the pros and cons of the therapy before you decide if it's right for you.

CAR T is approved to treat acute lymphocytic leukemia (ALL) in kids and young adults and certain types of adult non-Hodgkin's lymphoma. Doctors are testing it for other types of blood cancer in clinical trials.

Chemotherapy (chemo) and stem cell transplants are the first choices for treating these diseases. But if they don't work after at least two tries, or cancer comes back after treatment, CAR T may be an option. For some people, it could be the last chance for a cure.

Normally, T cells in your body hunt down and destroy cancer cells. They look for things on cells called antigens that don't match the ones of your body. The T cells flag that bad cell as "Trouble here!" and work on killing it.

But sometimes T cells miss the cancer because it's too much like your normal cells, or they don't launch a full-on attack, which lets the cancer grow. That's where CAR T comes in. It powers up your immune system by adding a specific receptor so it's easier for T cells to find and latch onto your cancer cells.

This kind of treatment is known as autologous immunotherapy because it's using your body's immune system and you don't need a donor.

There are two CAR T medicines: axicabtagene ciloleucel (Yescarta) and tisagenlecleucel (Kymriah). The treatment is done in a similar way no matter which medicine you get or the type of cancer you have.

Step 1: T-cell collection. A special machine collects T cells from your blood. During this process, called leukapheresis, you'll have two intravenous (IV) lines in veins in your arms. One IV sends your blood to the machine, and the other returns your blood to your body.

This doesn't hurt, but it can take a few hours. You can lie in bed or sit in a reclining chair while you have it. And you can read, listen to music, work on your computer, or do some other calm activity to pass the time.

Step 2: T-cell changes. Your cells are sent to a lab where a new gene is added to them. This makes the cells sprout special proteins on their surface. These chimeric antigen receptors, or CARs, allow the T cells to spot and attach to antigens on tumor cells.

The lab grows hundreds of millions of these new cells, now called CAR T cells. This usually takes a few weeks, though the time can be different for each person.

Step 3: Low-dose chemo. While you wait for the cells to grow, you may get a low dose of chemo for a few days to cut back on other immune cells in your body. Your doctor might call this lymphodepleting chemotherapy. With less competition, it will be easier for the new CAR T cells to do their job and spread.

Step 4: Infusion. The CAR T cells are frozen and shipped to the hospital or cancer center where you're being treated. They're put back in your body through an IV in a vein in your arm, like a blood transfusion.

The hope is that the CAR T cells will do a better job finding your cancer. And once they start attacking it, they'll multiply so they can find more cancer cells.

Step 5: Recovery. It takes 2-3 months to recover from CAR T. After you leave the hospital, you must stay near the treatment center for at least the first month so your doctor can watch for side effects. You'll need a full-time caregiver with you, too. You might end up back in the hospital to deal with complications.

As you recover, you're likely to feel very tired and won't want to eat much. And you'll need to ease back into normal life slowly.

CAR T has mainly been used in clinical trials. In one trial, all signs of cancer disappeared in about one-third of the people. For others, tumors got smaller but didn't go away.

CAR T-cells are supposed to keep working for years, so cancer shouldn't come back. But some experts say it's too early to know if that will happen.

Because it's affecting your immune system, CAR T can cause other changes in your body, too.

Cytokine release syndrome (CRS). This happens when CAR T-cells begin attacking cancer and trigger an immune response in your body. For some people, CRS may feel like a bad case of flu. In others, it can cause very low blood pressure, high fevers, and trouble breathing.

Doctors are still learning the best ways to handle these symptoms. One is with an arthritis medicine called tocilizumab (Actemra). If the doctor gives it soon enough, it can stop CRS.

Brain and nervous system problems. These usually happen in the first 2 months after your infusion. The most common ones are headache and feeling anxious. You might also be confused, have seizures, or not be able to talk at all for a few days.

Most of these go away, but they can be life-threatening for some people.

Serious infections. CAR T can also kill off B cells, another kind of white blood cell you need to fight germs and foreign invaders, so you're more likely to get sick. Also, if you had hepatitis B before, it could start up again.

New cancer. You could get a new type of cancer after CAR T, or your old cancer might come back. You should have your doctors watch for signs of cancer for the rest of your life.

CAR T-cell therapy is a one-time treatment, but it costs hundreds of thousands of dollars. And when you add in related costs, like hospital stays and home health care, the total may be closer to $1.5 million.

Talk to your insurance company. Be sure you know exactly what they cover.