CAR-T Cell Therapy: A “Revolution” in Cancer Treatment

Our immune system was designed to fight off foreign invaders such as viruses, bacteria — and cancer. But sometimes cancers can evade detection and continue to grow. A new treatment called CAR T-cell therapy retrains the immune system to make it a more efficient, and more effective cancer fighter.

“CAR-T is a revolution in cancer therapy. It is paradigm changing,” Dr. Siddhartha Ganguly, director of the Lymphoma/Myeloma Program at the University of Kansas, tells SurvivorNet.

How it Works

The immune system has its own way of tracking down harmful invaders like germs or cancer. It looks for proteins called antigens on the surface of these cells. Then it sends out an army of white blood cells — leukocytes — to destroy the invaders.

But sometimes the immune system can’t find the cancer on its own. Cancer cells can devise tricky ways of cloaking themselves and hiding.

That’s where chimeric antigen receptor (CAR) T-cell therapy comes in. It re-engineers your immune cells to help them track down your cancer. Like the fire-breathing monster in Greek mythology made from the head of a lion, the body of a goat, and the tail of a serpent, this chimera combines a T cell with a man-made receptor to recognize cancer.

What You Can Expect

The process starts when your doctor removes a sample of your blood through an IV. With a procedure called leukapheresis, your blood flows into a machine that separates out the T cells and then returns the other blood components (red blood cells, platelets, etc.) to you. Your T cells are sent out to a lab, where technicians insert an anti-cancer gene into them.

That new gene causes special receptors called chimeric antigen receptors to pop up on the surface of the T cells. Those receptors are like homing devices that will lock onto the matching antigen on the surface of your cancer cells.

You’ll first need treatment to prepare your body to receive the new, genetically modified T-cells. “Patients are primed with three to four days of a mild form of chemotherapy, so that their body does not reject those genetically modified cells,” Dr. Ganguly says. “And then those cells are infused, just like a blood transfusion.”

Life After CAR T-Cell Therapy

Once inside your body, the modified T cells will go to work against your cancer. “If you think about the previous immune system that was naïve, not doing anything and living happily in harmony with the cancer, and now those genes inserted are virulent,” Dr. Ganguly says. “They’re like the Pac-Man of the video game, if you remember from your childhood.”

CAR-T cells hunt down all of the cancer cells that carry the specific antigen they’ve been “trained” to target. Once they reach the cancer cells, they release toxins called chemokines. CAR T-cells both attack cancer cells directly, and signal your immune system to go after these cells. If all works as planned, the treatment should reduce or eliminate the cancer in your body.

Unlike chemotherapy and other traditional cancer drugs, CAR T-cell therapy is a living treatment. And it has had dramatic effects, leading to high rates of remission in some people with B-cell lymphoma.

One downside to this treatment is a cluster of side effects called cytokine release syndrome (CRS). When T cells attack the cancer, they trigger your body to release a flood of chemicals, called cytokines. In large enough numbers, cytokines can cause symptoms like a fever, low blood pressure, or a drop in oxygen level.

Another possible side effect is nerve damage (neurotoxicity), which can cause symptoms such as confusion, headache, problems with language, and rarely, more severe side effects such as seizures. CRS and nerve damage can range from mild to severe. People with the most severe cases will need to receive care in a hospital, but these side effects are usually treatable.

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