Chimeric antigen receptor T-cell therapy, or CAR-T therapy, is a treatment that helps your T-cells fight certain types of cancer.

Your T-cells are the parts of your immune system that recognize and help kill foreign cells. CAR-T therapy gives your T-cells the right receptors to bind to cancer cells, so your immune system can destroy them.

Currently, CAR-T therapy is only used for blood cancers, but much research is being done on expanding its use. Read on to learn more about how this treatment works, its benefits and risks, and the outlook for CAR-T therapy.

T-cells are cells in your immune system. They bind to proteins on the surface of cells your body doesn’t recognize, also called foreign cells. Some T-cells destroy these cells themselves, while other types signal the rest of your immune system to destroy those foreign cells.

Each type of T-cell only bonds to one type of protein. So, to have your immune system fight cancer cells, you need T-cells with certain receptors. These receptors allow them to bind to the specific cancer cell protein. The process of making those cells to fight cancer is called CAR-T therapy.

Making these cancer-fighting T-cells involves the following steps:

  1. T-cells are collected from your blood.
  2. Your T-cells are then taken to a lab, where their genes are changed to produce what’s called chimeric antigen receptors specific to your type of cancer. These T-cells can now bind to cancer cells.
  3. After the lab grows lots of these new T-cells, they’re infused back into your bloodstream.
  4. You may also get low dose chemotherapy before your infusion to lower the number of other immune cells you have and allow T-cells to work better. According to 2021 research, your dose of T-cells will be carefully balanced to be as therapeutic as possible while limiting toxicity.
  5. After your infusion, the CAR T-cells bind to your cancer cells and destroy them. While this happens quickly, 2022 evidence suggests the CAR T-cells can continue to destroy cancer cells for months after the infusion.

CAR-T therapy is not approved as a first-line treatment for any type of cancer. That means you have to try at least two treatments (depending on your type of cancer) that do not work before trying CAR-T therapy.

Currently, it’s only approved for blood cancers like leukemia and lymphoma, including:

The main benefit of CAR-T therapy is that it can be curative for people whose blood cancer has not responded to other types of treatments. While CAR-T therapy is often considered a last resort, it is often an effective one.

CAR T-cell therapy response rates

According to the National Cancer Institute, response rate refers to the percentage of people whose cancer shrinks or disappears after treatment. In a 2020 research review, overall response rates for different cancers when treated with CAR-T include:

  • Relapsed/refractory diffuse large B-cell lymphoma: 52 to 82 percent
  • B-cell acute lymphoblastic leukemia: 80 percent
  • Chronic lymphocytic leukemia/small lymphocytic lymphoma: 82 percent

Many people in these clinical trials went into complete remission.

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CAR-T therapy has many benefits, but it also has some potential risks, including:

  • Treatment not working. Very few treatments work 100 percent of the time. It’s possible that CAR-T therapy won’t kill all your cancer cells. And because it’s often used as a last resort, you may not have other options if CAR-T therapy doesn’t work.
  • Relapse. Your cancer can come back even if the treatment works at first. How likely this is depends on your overall health and your type of cancer, so this can’t always be predicted. But 2020 research suggests that certain types of cancer, such as large B-cell lymphoma, seem more likely to come back after CAR-T therapy.
  • Side effects. There are also many potential side effects of CAR-T therapy, and some can be serious.
  • Lack of data. The first CAR-T therapy was approved in 2017. This means there’s still limited data on the long-term effects of the treatment, including its overall effectiveness.

Side effects of CAR-T therapy can be severe but usually get better with treatment.

Contact a doctor if you have any of the following symptoms, especially if they become more severe over time:

Many of these are symptoms of mild cytokine release syndrome, also known as CRS or cytokine storm. This is a common side effect of CAR-T therapy. It occurs when the CAR T-cells multiply in your body and cause your body to make too many cytokines — chemicals that can help T-cells function but also cause severe flu-like symptoms.

Side effects of severe cytokine release syndrome include:

A condition called immune effector cell-associated neurotoxicity syndrome (ICANS) is also a potential severe side effect of CAR-T therapy.

Symptoms include:

Well developed guidelines and protocols exist to diagnose and manage both CRS and ICANS. According to a 2019 review, management uses a combination of steroids and drugs such as tocilizumab (Actemra). Despite proper management, some cases may still be life threatening or fatal.

Other potential severe side effects of CAR-T therapy include anaphylaxis and extremely low blood cell counts.

A 2020 review suggests that “turning off” CAR T-cells after they kill cancer cells can reduce these severe side effects. This research is in its early stages, but there are some promising potential ways to turn off CAR T-cells.

CAR-T therapy can be very expensive. The main cost of treatment is the drug itself.

Axicabtagene ciloleucel (Yescarta) is a CAR-T option approved by the Food and Drug Administration (FDA) for treating large B-cell lymphoma. According to a 2018 study, this treatment costs $373,000. Another CAR-T drug, tisagenlecleucel (Kymriah), costs $475,000.

These numbers do not include other medical expenses surrounding treatments, including doctor’s appointments, tests, prescriptions, and more. Additionally, expenses vary depending on how long your course of treatment needs to be.

Treatment may be covered by insurance if it’s shown to be clinically appropriate for you and a doctor prescribes a medication approved by the FDA. Most private insurance companies cover CAR-T to some extent, but the amount they cover can vary.

Beginning on October 1, 2019, the Centers for Medicare and Medicaid Services (CMS) announced that CAR-T was covered by Medicare. The amount covered by Medicare will depend on whether you’ve met your deductible, and other individual factors. Some Medicaid programs also cover CAR-T.

CAR-T therapy can be a very successful, long-term treatment for people with blood cancers that have not responded to other treatments.

Treatment can be physically difficult and involves a hospital stay of at least 2 weeks. But many people who have undergone CAR-T cell therapy have added months or years to their lives.

CAR-T is currently only approved for blood cancers, but much research is being done on its use for other cancers. Research is also being done on making this therapy safer and even more effective, and the future of this therapy looks very promising.