What is CAR T-Cell Therapy and how does it work?

CAR (Chimeric Antigen Receptor)-T
cell therapy is a type of immunotherapy drug that changes the patient’s
own T cells so they are able to recognize and attack cancer cells.

 

The T cells are cells involved in the immune system and they play several important roles in the body’s fight against disease, and specifically against a number of cancers.  They help the immune system react to an invasive disease and directly kill those diseased cells.

CAR T-cell therapy has been extremely effective in many patients, and in some cases, the treatment have been able to eliminate all signs of cancer.

However, CAR T-cell therapy doesn’t work for every patient or every disease. Some have benefited for a short time before relapsing. Doctors are studying the reasons for these different responses within different patient’s populations.

The treatment is done by firstly taken blood from the patient’s body and in that special blood draw, certain blood components are extracted and the rest of the blood is pumped back into the patient.

Once the patients T cells are removed, they are sent to a specific laboratory  where they undergo a genetic modification so they can produce a protein to  recognize another protein  on the surface of cancer cells, and this recognition allows the modified T cells to identify and attack the cancer.

These modified T cells multiply by the hundreds of millions and then they are infused back into the patient to fight the disease

 After many years of medical and laboratory research as well as specific clinical trials, in 2017 the USA Food and Drug Administration approved the use of two CAR T-cell therapies ( Kymriah and  Yescarta).  

Both of these compounds use genetically modified cells that recognize a protein (called CD-19) on the surface of cancerous B cells.

  • Kymriah is given to pediatric as well as young adult patients age 25 or younger with B-cell acute lymphoblastic leukemia. It has also been approved for adult patients with certain types of large B-cell non-Hodgkin lymphoma who have relapsed on haven’t not responded to standard treatments.
  • Yescarta has been approved for patients with large B-cell non-Hodgkin lymphoma that has relapsed or does not respond to standard treatments.

To be eligible for either treatment, patients must have been treated unsuccessfully with at least two other cancer therapies.

Removing the specific blood products and modifying and expanding a patient’s T cell population takes a few weeks..

When the CAR T cells are ready for use, they are sent back to the hospital for an infusion. Before the infusion, patients are usually given a short course of chemotherapy. This weakens their existing immune system, giving the engineered T cells a better chance of expanding and fighting the cancer.

The infusion of the modified T cells is quick, typically lasting less than an hour. Afterwards, patients must remain in the hospital for several days for monitoring. After they are discharged, patients must stay near the hospital for several weeks. 

CAR T-cell therapy’s side effects can be serious and even life-threatening, especially if left untreated.

A serious side effect is called cytokine release syndrome, when too many cytokines are produced, leading to a dangerously high fever, low blood pressure, difficulty breathing and even organ failure. Doctors and medical staff monitor for this condition very carefully and have effective treatments to control it in those patients who develop it.

CAR T-cell therapies can also have temporary but serious neurological effects, including confusion, slurred speech and seizures.

Other side effects might include:

  • low counts of red and white blood cells and platelets
  • chills and shaking
  • nausea, vomiting and diarrhea.

Although these side effects are reasonable known, we must remember that  CAR T-cell therapy is a new treatment and doctors continue monitoring patients to uncover any long-term impact on their bodies.