All About Car T-Cell Therapy

While tried and true methods of treating cancer such as cancer and radiation therapy work effectively for most patients, there are new methods of cancer treatment that can often be more successful for patients than the old school treatment methods. CAR T-Cell Therapy is a new and upcoming treatment that many oncologists have started using to treat blood cancers (leukemia, lymphoma, etc).

Chimeric Antigen Receptor T-Cell Therapy, or CAR T-Cell Therapy, is the latest immunology cancer treatment which uses a patient’s own immune cells for their treatment. CAR molecules are medically engineered molecules that recognize and destroy lymphoma or leukemia cells.

Steps of CAR T-Cell Treatments

There are 6 steps to making CAR T-Cells: Leukapheresis, T-Cell Engineering, CAR T-Cell transport, Chemotherapy, CAR T-Infusion, and CAR T-Attack.

The first step is Leukapheresis. This is the process in which the T-Cells are obtained from the patient’s body. The patient’s blood is removed from the patient’s IV, then the blood is passed into a machine which separates the T-Cells from the blood. The non T-Cells are returned to the patient’s body.

The second step is T-Cell Engineering. In this step, T-Cells are genetically engineered to specifically target lymphoma cells in the patient’s body. The T-Cells are engineered to have chimeric antigen receptors (CAR). The CAR receptors on the T-Cells connect to a protein on the lymphoma cells.

The third step is the transportation of the CAR T-Cells. Once the engineering of the CAR T-cells is finished at the processing center, the CAR T-Cells are frozen to be transported to the patient’s specific treatment center.

The fourth step is Chemotherapy. The patient has to undergo low dose chemotherapy three-four days prior to the CAR T-Cell treatment. The low dose chemotherapy suppresses the immune system’s reaction to the CAR T-Cells entering the body and attacking the lymphoma cells.

The fifth step and sixth step are CAR T-Infusion and CAR T-Attack. These steps occur simultaneously in the patient’s body. The CAR T-Cells are infused into the patient’s body through an IV, and most of the time the T-Cell infusion takes less than an hour. Upon entry of the CAR T-Cells in the body, the T-Cells begin to attack the lymphoma cells using the receptors. In these steps of the CAR T-Cell treatment, the patient has to be continuously observed by their oncologist for side effects.

FDA Approved CAR T-Cell Therapies

There are about five types of approved CAR T-Cell Treatments that are used frequently: Yescarta, Tecartus, Abecma, Kymriah, and Actemra.

Yescarta is used for treatment of adult patients with relapsed large B-cell lymphoma after two or more rounds of high dose chemotherapy.

Tecartus is used for the treatment of adult patients who have a relapse of lymphoma. This treatment tends to have an overall accelerated response rate in the patient’s body (compared to other types of CAR T-Cell treatments).

Abecma is used for the treatment of adult patients who have a relapse of multiple myeloma after four or more rounds of high dose chemotherapy.

Kymriah is used for the treatment of patients up to the age of 25. This treatment is mainly used for patients who have had a second (or third, fourth, etc) relapse of large B-Cell lymphoma.

Actemra can be used for adult and pediatric patients (who are 2 years or older). To be used on pediatric patients, the patient has to have a life threatening disease (caused by CAR T-Cell receptors), such as cytokine release syndrome (CRS).

Drawbacks of CAR T-Cell Therapy

Although CAR T-Cell Therapy is as efficient as chemotherapy as a cure for cancer, CAR T-Cell Therapy is known to have multiple life-threatening side effects.

For example, the most common side effect of CAR T-Cell Therapy is Cytokine Release Syndrome (CRS). CRS is where the body releases too much Cytokines (chemical messengers that help the T-Cells carry out their function) in order to make up for the CAR T-Cells furiously attacking the lymphoma cells in the patient’s body. CRS can cause low blood pressure, cardiac arrest, cardiac failure, etc. Patients who have CRS need to be constantly monitored in the Intensive Care Unit (ICU).

Some other life-threatening diseases that are potential side effects of CAR T-Cell Therapy are Macrophage Activation Syndrome), Neurologic Toxicities (can cause language impairment, brain damage, etc), Tumor Lysis Syndrome (causes organ damage due to the breakdown of dying cancer cells in the body), and many other life threatening conditions as well.

The Uncertainty of CAR T-Cell Treatment

Some statistics of CAR T-Cell treatment are very promising. For example, the Leukemia and Lymphoma Society states that “in some studies, up to 90 percent of children and adults..whose disease had relapsed multiple times, or failed to respond to standard treatments and therapies, achieved remission after receiving CAR T-Cell Therapy.”

However, other studies and clinical trials have shown that CAR T-Cell Therapy is the cause of many other life-threatening conditions on top of cancer, which can further hinder a cancer patient’s recovery. Furthermore, most patients involved in CAR T-Cell Therapy trials have only been evaluated for a short amount of time after receiving treatment. This does not show future implications of CAR T-Cell Therapy on patients in the future, including when they fully recover from cancer after receiving chemotherapy.

What to do next?

Before a patient decides to undergo CAR T-Cell Therapy, it is important for the patient and his/her family to do research. Although CAR T-Cell Therapy can be an efficient treatment, its future implications have not been studied enough for it to be considered a “normal” cancer treatment, such as chemotherapy. In the end, the patient should do whichever treatment that he/she feels comfortable with and that their oncologist recommends.

Sources:

https://www.cancer.gov/about-cancer/treatment/research/car-t-cells

https://www.lls.org/treatment/types-treatment/immunotherapy/chimeric-antigen-receptor-car-t-cell-therapy

https://lymphoma.org/aboutlymphoma/treatments/cartcell/