CAR T-cell therapy is approved for some cancers but is still being researched as a treatment for small cell lung cancer (SCLC).

Chimeric antigen receptor (CAR) T-cell therapy is a cancer treatment that involves altering the body’s own immune cells so they are better equipped to target and eliminate cancer cells.

To date, the United States Food and Drug Administration (FDA) has approved CAR T-cell therapy to treat certain cancers of the blood and lymphatic system. However, clinical trials are underway to determine the safety and efficacy of CAR T-cell therapy as a treatment for SCLC.

This article describes what CAR T-cell therapy is and its success rate as a cancer treatment. We also outline the disadvantages of this therapy and provide information on costs and insurance coverage.

CAR T-cell therapy is so-called because it involves the use of a type of immune cell called “T-cells”. These white blood cells help fight infection and disease.

T-cells have proteins called receptors, which attach to antigens ― proteins that trigger the immune system to make antibodies. Cancer cells have antigens, but the body’s T-cells may lack the appropriate receptors to attach to these antigens. As a result, the T-cells will be unable to remove the cancer cells.

CAR T-cell therapy involves extracting a person’s own T-cells from their blood and adapting the cells in a laboratory. In the lab, the T-cells receive a gene for the chimeric antigen receptor (CAR), which helps the T-cells attach to a specific cancer cell antigen. Different cancers have different antigens, so the T-cells will receive a CAR that scientists have tailored to target a specific cancer’s antigen.

Over several weeks, the CAR-T cells grow and multiply in the lab. Once there is a sufficient number of T-cells, the person will receive them via an intravenous (IV) infusion. The CAR-T cells can then begin targeting and destroying the cancer cells.

According to the American Cancer Society (ACS), the United States FDA has so far approved CAR T-cell therapy for treating multiple myeloma, and certain types of lymphoma and leukemia.

A 2021 review notes that while T-cells show promise in treating certain cancers of the blood and lymph, they have shown less success in treating solid tumors, such as those that develop in SCLC. This is because the blood vessels and cells surrounding solid tumors suppress the immune system, leading to a state called “T-cell exhaustion”. This is where the T-cells no longer function effectively against cancer.

However, scientists are working to identify ways to increase the effectiveness of T-cells against solid tumors.

Scientists have found that SCLCs feature an antigen called delta-like protein 3 (DLL3). A 2023 pre-clinical trial investigated the efficacy of a CAR T-cell therapy designed to target DLL3 in mice with SCLC.

The researchers further adapted the CAR T-cells to express a protein called “interleukin-18 (IL-18)”, which is involved in regulating the immune system’s response to disease. They hoped this may protect against T-cell exhaustion.

The study found that the DLL3-targeting CAR T-cells significantly increased anti-tumor activity. Moreover, the addition of IL-18 also:

  • reduced T-cell exhaustion
  • increased CAR T-cell multiplication and longevity
  • produced more T-cells capable of “remembering” the DLL3 antigen so that they could target this antigen in the future
  • activated immune cells called “tumor-infiltrating lymphocytes” (TILs), which enter tumors to kill them from within

Research into the use of CAR T-cell therapy for SCLC is ongoing. As of 2020, there were more than 250 clinical trials worldwide evaluating the safety and efficacy of CAR T-cell therapy for the treatment of solid tumors.

Get involved

If you or a loved one has SCLC, you may be able to participate in clinical trials involving CAR T-cell therapy. The best place to start is by speaking with your doctor or oncology team. They’ll be able to inform you of any local trials that you may qualify for and make sure it won’t interfere with your current treatment.

You can also visit to learn about trials that are looking for participants.

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According to the ACS, CAR T-cell therapy can cause serious and potentially life threatening side effects. For this reason, a person must receive this therapy in a medical center that is specially trained in its use. People should also undergo regular monitoring for several months following the therapy.

Some potential side effects of CAR T-cell therapy are outlined below:

Cytokine release syndrome (CRS)

When CAR T-cells multiply within your body, they can release large numbers of chemicals called “cytokines” into your blood. This can increase the activity of your immune system, resulting in a serious and potentially life threatening condition called cytokine release syndrome (CRS).

According to a 2022 review, CRS is the most common adverse health effect associated with CAR T-cell therapy.

Mild symptoms of CRS include:

Severe signs and symptoms include:

Nervous system problems

CAR T-cell therapy can affect your nervous system, which may lead to the following symptoms:

Due to the above risks, individuals should avoid the following activities for several weeks after receiving CAR T-cell therapy:

  • driving
  • operating heavy machinery
  • any other potentially dangerous activities

Other serious side effects

Other serious side effects that may occur as a result of CAR T-cell therapy include:

  • allergic reactions during the infusion
  • abnormal levels of minerals in the blood
  • weakening of the immune system
  • low blood cell counts, which can increase the risk of the following:
    • infections
    • bruising or bleeding
    • fatigue

A 2022 review notes that CAR T-cell therapy is an expensive treatment, costing between $373,000–$475,000 per infusion. The authors add that a person can expect to pay an additional $79,466–$85,267 for continued monitoring in a hospital setting. Your insurance may cover part of this cost, but it will vary by plan.

According to the Dana-Faber Cancer Institute (DFCI), insurance providers may consider coverage for CAR T-cell therapies on a case-by-case basis. They add that this is the typical procedure for newer therapies.

As noted, the United States FDA has not yet approved CAR T-cell therapy for the treatment of SCLC. In the meantime, you can ask your doctor if you may be eligible to enroll in any clinical trials.

CAR T-cell therapy is a cancer treatment that involves extracting and altering the body’s T-cells so that they are better equipped to target and destroy cancer cells.

The United States FDA has so far approved CAR T-cell therapy for treating certain blood and lymphatic cancers. However, researchers are conducting ongoing clinical trials to determine the safety and efficacy of CAR T-cell therapy for the treatment of SCLC. Some of this early research appears promising.

CAR T-cell therapy can cause serious and potentially life threatening adverse health effects. Anyone who is considering participating in a clinical trial should discuss the potential risks and benefits with their doctor and the treatment team leading the research.