What is CAR T-cell therapy and how does it work?

CAR T-cell therapy is a personalized treatment that uses a patient's own immune cells to fight certain cancers and autoimmune diseases. By harnessing and reprogramming a patient’s own immune cells, this therapy offers a new option for those who have not responded to conventional treatments. While mainly used for blood cancers, recent research is also exploring its potential in severe autoimmune diseases like lupus.

What Is CAR T-Cell Therapy?

Chimeric Antigen Receptor (CAR) T-cell therapy is an advanced form of immunotherapy that has transformed the treatment landscape for several hard-to-treat blood cancers. CAR T-cell therapy involves the use of T cells—specialized white blood cells—engineered in the lab to express chimeric antigen receptors (CARs) that enable them to recognize and attack specific cancer or disease cells. Scientists collect T cells from a patient and genetically modify them to produce CARs on their surface. These synthetic receptors are designed to target specific proteins (antigens) found on cancer cells or, in some cases, malfunctioning immune cells

Unlike traditional chemotherapy, which attacks rapidly dividing cells indiscriminately, or standard immunotherapy, which boosts the immune system in general, CAR T-cell therapy gives T cells a precise “homing device” to seek out and destroy disease cells.

How CAR T-Cell Therapy Works

CAR T-cell therapy is a multi-step process that transforms a patient’s own immune cells into powerful cancer-fighting agents. By collecting, engineering, and reintroducing T cells equipped with synthetic receptors, this therapy enables the immune system to specifically target and destroy disease cells that were previously able to evade detection. The entire process can take several weeks. Each stage of this innovative treatment is outlined below.

Step-by-Step Overview

1. Leukapheresis: Blood is drawn from the patient, and T cells are separated out.
2. Genetic Modification: In the lab, a gene for the CAR is inserted into the T cells, enabling them to recognize a specific antigen on the target cells.
3. Cell Expansion: The modified T cells are multiplied until there are millions to billions of cells ready for infusion.
4. Preconditioning Chemotherapy: Before the CAR T cells are returned, the patient receives chemotherapy to reduce other immune cells and help the new cells work effectively.
5. Re-infusion: The engineered CAR T cells are infused back into the patient, where they seek out and destroy target cells.
6. Immune Attack: Once inside the body, CAR T cells patrol for cells bearing the target antigen, bind to them, and trigger a powerful immune response to eliminate them.

FDA-Approved CAR T-Cell Therapies

The FDA has approved several CAR T-cell therapies for various hematologic malignancies:

• Kymriah (tisagenlecleucel): Approved for pediatric and young adult acute lymphoblastic leukemia (ALL), and certain lymphomas.
• Yescarta (axicabtagene ciloleucel): Used for large B-cell lymphoma and follicular lymphoma.
• Tecartus (brexucabtagene autoleucel): Indicated for mantle cell lymphoma (MCL) and ALL.
• Breyanzi (lisocabtagene maraleucel): Approved for large B-cell lymphoma and follicular lymphoma.
• Abecma (idecabtagene vicleucel) & Carvykti (ciltacabtagene autoleucel): Both target BCMA for treatment of multiple myeloma.

What Conditions Does It Treat?

Originally developed for certain blood cancers, CAR T-cell therapy applications are rapidly expanding as research uncovers its potential benefits in other conditions, including autoimmune disorders. The following section outlines the cancers and emerging diseases where CAR T-cell therapy is currently used or under investigation, highlighting its growing impact in modern medicine.

Blood Cancers:

• Acute Lymphoblastic Leukemia (ALL)
• Diffuse Large B-Cell Lymphoma (DLBCL)
• Follicular Lymphoma (FL)
• Mantle Cell Lymphoma (MCL)
• Multiple Myeloma (MM)

Emerging Uses (currently being investigated in clinical trials, not yet FDA-approved for these indications):

• Systemic lupus erythematosus (lupus)
• Myositis
• Scleroderma

Related questions

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How Long Does It Take to Work?

After getting the CAR T-cells infused, it takes 1-2 weeks for them to reach peak levels in the body. During this time, the T-cells work to fight cancer cells. Most patients begin to see results within weeks to a few months after infusion. Factors influencing response include disease burden, patient profile, and the specific CAR construct used.

How Effective Is CAR T-Cell Therapy?

CAR T-cell therapy has transformed outcomes for many patients with difficult-to-treat cancers, offering hope where other treatments have failed. Its effectiveness is measured by high remission rates and durable responses in several blood cancers, though results can vary depending on the disease and patient factors. A recent study showed that 56% of patients taking CAR T-cell therapy for a blood cancer such as lymphoma or multiple myeloma had a complete response. While generally not curative, CAR T-cell therapy can help patients achieve remission for many months.

Remission Rates:

• ALL: Complete remission rates of 55–90% in clinical trials.
• DLBCL: Remission rates of 30–80%, with some patients remaining cancer-free for years.
• MM: In patients with relapsed/refractory MM, complete remission rates of 13%-78% have been observed.

In ALL, relapse occurs in about 40-50% of patients. In MM patients, the response can last years. In a long-term study of Carvykti, median progression-free survival was found to be 35 months, with 63% overall survival at 36 months.

Side Effects and Safety

CAR T-cell therapy can cause significant side effects that require careful management. Because this treatment activates the immune system, patients may experience unique reactions not typically seen with standard cancer therapies. Understanding these potential risks and the safety measures in place is essential for anyone considering or undergoing CAR T-cell therapy. Below we outline the most common side effects, how they are monitored, and the strategies used to ensure patient safety throughout the treatment process.

• Cytokine Release Syndrome (CRS): A potentially serious immune reaction causing fever, low blood pressure, and organ dysfunction; usually managed with medications like tocilizumab.
• Neurotoxicity: A condition called immune effector cell-associated neurotoxicity syndrome (ICANS) can cause confusion, seizures, and speech difficulties; typically reversible with prompt treatment.
• Infections and Low Blood Counts: Due to immune suppression, patients are at increased risk for infections and may experience anemia or low platelets.

Patients are closely monitored in specialized centers for several weeks after therapy to manage side effects. Other side effects may occur. Discuss all possible side effects with your healthcare provider, and ways to manage them.

What Is the Cost of CAR T-Cell Therapy?

The cost of CAR T-cell therapy is a major consideration for patients, families, and healthcare systems. As a highly personalized and complex treatment, it involves not only the engineering of immune cells but also specialized medical care and monitoring.

The average cost range of CAR T-cell therapy is $373,000 to $475,000 per treatment in the U.S.; total costs (including care and complications) can exceed $1 million per patient. Most insurance plans cover FDA-approved uses, but access can be limited by cost and treatment center availability. Some manufacturers offer financial assistance programs for eligible patients that meet financial and other requirements.

CAR T-Cell Therapy in Autoimmune Diseases

Early clinical trials in lupus and other autoimmune diseases such as idiopathic inflammatory myositis and systemic sclerosis have shown remarkable rates of remission, with some patients achieving drug-free remission for months to years. In autoimmune settings, CAR T cells target and eliminate malfunctioning immune cells (often B cells) that drive disease, rather than cancer cells. Currently, CAR T-cell therapies are not FDA-approved for autoimmune diseases, and are only available in clinical trials at this time.

Conclusion

CAR T-cell therapy represents a major advance in the treatment of certain blood cancers, offering a lifeline to patients who have exhausted other options. While it comes with significant risks and high costs, its ability to induce lasting remissions—and its emerging promise in autoimmune diseases—make it one of the most exciting areas of modern medicine. Treatment takes several weeks followed by long-term monitoring, as side effects may include cytokine release syndrome and nervous system toxicity.

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