How CAR T-Cell Therapy 'Cured' 2 Cancer Patients

Researchers have announced that two patients who had chronic lymphocytic leukemia (CLL) in 2010 are still cancer-free a decade later after receiving a promising cancer treatment called CAR T-cell therapy.

The details of the patients’ cases were published in the journal Nature in early February 2022.

What Is CAR T-Cell Therapy?

Chimeric antigen receptor T-cell treatment is more commonly called CAR T-cell therapy. It’s a type of cancer treatment that uses T cells—white blood cells that are an important part of the immune system.

In CAR T-cell therapy, a sample of a patient’s T-cells is taken to a lab. Some genes in the cells are changed to make them better at finding proteins on cancer cells called antigens.

During this process, a chimeric antigen receptor (CAR) for the type of cancer a person has is added to the T-cells. From start to finish, it takes a couple of weeks to get the cells ready.

When the changed cells are better equipped to fight cancer cells, they are put back into the patient’s body through an IV (infusion).

However, CAR T-cell therapy also has some side effects such as fever, chills, vomiting, dizziness, agitation, and seizures. Therefore, patients usually have the treatment at a medical center that is specially trained to give it.

Lasting Effects CAR T-Cell Therapy 

In the case of the Nature study, the researchers followed three patients with chronic lymphocytic leukemia (CLL)—one of the most common leukemias in adults. This type of cancer starts in the bone marrow and moves into the blood.

J. Joseph Melenhorst, PhD, a coauthor of the study and an immunologist at the University of Pennsylvania, told Verywell that two of the patients went into complete remission after receiving the treatment in 2010.

The researchers analyzed the patient’s CAR T-cells over time. Ten years later, the cells were still destroying and attacking cancer in the patient's body. No leukemia cells were found.

“Subjects treated on this therapy had no functioning B cells (a lymphocyte that produces antibodies to fight bacteria and viruses) anymore,” said Melenhorst. “On the one hand, it’s a cure and on the other hand, the cells managed relatively well with the therapy.”

In the initial treatment phase, the subjects’ immune response was dominated by CD8+ cells, which directly attack cancerous cells. Later, an unusual form of cytotoxic (i.e., cancer-killing) CD4+ helper T cells came to dominate the immune response and continued to attack cancerous cells and maintain cancer remission.

“It certainly is a breakthrough. The subjects were diagnosed with chronic lymphocytic leukemia a long time ago, two or three decades ago, and multiple therapies failed,” Melenhorst said. “Because of CAR T-cell therapy, they could now do what they always wanted to do and pick up new hobbies.”

Barriers to Treatment

The patients received CAR T-cell therapy in 2010 as part of a trial at the Abramson Cancer Center and the Perelman School of Medicine at the University of Pennsylvania in Philadelphia.

The trial led to the approval of the first CAR T-cell therapy called Kymriah (tisagenlecleucel) in 2017 for children and young adults with refractory or relapsed B-cell acute lymphoblastic leukemia.

In 2018, the treatment was approved for certain adult patients with refractory or relapsed large B-cell lymphoma.

According to Melenhorst, CAR T-cell therapy is currently not approved by the FDA to treat CLL, but it is approved to treat other kinds of cancers.

“We have the same therapy available via commercial entities for acute lymphocytic leukemia (ALL), non-Hodgkin’s lymphoma, and multiple myeloma,” Melenhorst said. “But for CLL, we have a little bit more work to do.” 

There are other barriers to getting CAR T-cell therapy, one of which is the cost. Melenhorst said that the price for the therapy itself can be $300,000 to over $400,000.

While the cost could certainly keep people from accessing the therapy, Melenhorst said that some patients are able to receive the treatment because they’re taking part in clinical trials. 

“There’s a big database of registered trials in the United States and elsewhere. You’ll find hundreds, if not thousands at this point, of trials that have CAR T-cell as the main therapy,” said Melenhorst, adding that CAR T-cells “are now being developed for immune diseases” as well.

CAR T-Cell for Other Cancers 

While CAR T-cell therapy can provide long-lasting immunity against certain types of cancers, the therapy does not work for all patients or for all types of cancers.

Based on the findings of the study, Melenhorst is now planning to look at whether similar strategies and treatments may apply to other blood cancers.

“We are also evaluating how this treatment and strategy can apply to solid tumors, which are far more complicated to treat compared to liquid tumors, the blood cancers,” Melenhorst said. “This work really caused an opportunity to inspire additional work using this approach in other cancers.”

Melenhorst adds that several types of cancers produce solid tumors surrounded by proteins and other cells that CAR T-cells are unable to get to and attack.

Other cellular therapies that are being studied include:

• T-Cell Receptor (TCR) Therapy: Harvests T cells from the patient and engineers them to target specific proteins inside a cancer cell, then infuses the modified cells back into the patient
• Tumor-Infiltrating Lymphocyte (TIL) Therapy: Uses T cells harvested from the patient and cultured in a lab with a substance produced by lymphocytes (lymphokines), then infuses the modified cells back into the patient to attack tumor cells
• Natural Killer (NK) Cell Therapy: Uses donor lymphocytes to attack abnormal cells