Chimeric antigen receptor (CAR) T-cell therapy

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science at CTCA.

This page was reviewed on April 29, 2022.

Chimeric antigen receptor (CAR) T-cell therapy is a kind of immunotherapy, which uses your body’s immune system to fight cancer. It involves changing some of the immune cells in your body so they can better fight and kill cancer cells. It may be a treatment option if you have certain blood cancers or multiple myeloma and other therapies aren’t working.

T-cells and B cells are the two main types of white blood cells, called lymphocytes, that help your immune system fight off invaders. T-cells do this by identifying proteins on the surface of invading cells. These proteins are called antigens. T-cells have receptors that latch onto the antigens and destroy the invading cells. The T-cell has to have the right receptor—one that fits the antigen on the invading cell—to latch on and destroy it.

Cancer cells have antigens, and CAR T-cell therapy re-engineers the body’s T-cells to add receptors that latch on and destroy the cancer cells. CAR T-cell therapy removes T-cells from the blood and changes them in the lab by inserting genetic information that tells them to make the receptors for specific types of cancer cells. The re-engineered T-cells are then put back in your body so they can identify and kill the cancer cells.

FDA-approved CAR T-cell therapies

CAR T-cell therapy has been available since the U.S. Food and Drug Administration (FDA) first approved the therapy in 2017. To date, the FDA has approved six versions of CAR T-cell therapy to treat several types of blood cancer, including:

Different types of cancer cells have different antigens, so each version of CAR T-cell therapy contains receptors that are engineered for a specific type of cancer cells. CAR T-cell therapy may also be used to treat mediastinal large B-cell lymphoma, high-grade B-cell lymphoma and follicular lymphoma.

Timeframe for CAR T-cell therapy

It may take several weeks to undergo CAR T-cell therapy.

In the first step, doctors remove T-cells from the blood, then connect two intravenous (IV) lines to the body, usually in the arms. One line removes the blood, while the other returns it to your body. After it is removed, the blood passes through a machine that separates out the white cells (which include T-cells) before returning the blood to the body. In some cases, a patient may have a central line or catheter leading into the heart’s main artery instead of two IV lines.

The process of collecting the cells is called leukapheresis.It can take two or three hours. You may experience muscle spasms, numbness or tingling because of low calcium levels, which may be treated by replacing the calcium through an IV or by mouth.

Before the T-cells are returned to the body, chemotherapy may be used to kill additional cancer cells. Once back in the body, the T-cells begin reproducing and increasing their attack.

How to prepare for CAR T-cell therapy

You should arrange for a ride to your treatment, and you’ll likely be staying in a hospital afterward. You may need to avoid driving, operating heavy equipment or other potentially risky activities for a few weeks, due to potential side effects. Your doctors will schedule follow-up visits with lab tests, imaging and exams.

Understanding potentially serious side effects

While it’s provided new hope for some patients, CAR T-cell therapy also has limitations. The cancer may not respond well to treatment, or the cancer may recur—or come back —later on. In some cases, the cancer cells may stop making the antigen targeted by the therapy, which means the T-cells that were engineered for that specific antigen won’t work. This is called antigen loss.

CAR T-cell therapy may also cause potentially serious side or even life-threatening effects. One such side effect is called cytokine release syndrome (CRS), which happens when CAR T-cells release lots of chemicals called cytokines in the blood. Cytokines help ramp up the immune system, but they also cause inflammation. Symptoms of CRS range from flu-like symptoms to organ failure and even death. In mild cases, patients may experience:

  • Fever
  • Headache
  • Fatigue
  • Body aches
  • Vomiting
  • Diarrhea
  • Rash.

In serious cases, blood pressure may drop and fever increase, and some patients may have severe inflammatory reactions, such as:

  • Irregular heartbeat (arrhythmia) and other cardiovascular problems, including possible heart failure
  • Liver and kidney failure
  • Fluid in the lungs (pulmonary edema) and lung failure

Your doctors will monitor you for CRS. Severe cases may be treated with a drug called tocilizumab.

Some patients also have side effects that affect the nervous system, or neurological side effects. These may include:

  • Confusion and disorientation
  • Trouble speaking or understanding
  • Tremors or seizure-like activity
  • Lack of awareness
  • Loss of balance

Your doctors will watch for these neurological side effects, too. They may go away in a few days. If they don’t or if they’re severe, talk to your doctor about available treatments for these side effects.

Other possible side effects of CAR T-cell therapy include:

  • Allergic reaction to the infusion
  • A weakened immune system, which raises risk of infection
  • Low blood cell levels, which increases risk of fatigue, bruises and bleeding
  • Changes in blood levels of minerals, including potassium, phosphorus and sodium

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