CAR-T Cell Therapy
CAR-T-cell immunotherapy is a type of immunotherapy. It is a way to get immune cells called T cells (a type of white blood cell) to fight cancer by modifying them in the laboratory so that they can identify and destroy cancer cells. CAR T-cell therapy is also sometimes referred to as a type of cell-based gene therapy, as it involves altering the genes within T cells to make them more effective at fighting cancer.
T cells are present in our bodies and typically move to locate and eliminate defective cells. When exposed to a new infection or disease, the body produces T cells to combat that particular infection or disease. The body then stores a portion of the antigen so that if it encounters the infection again, it can immediately recognize and destroy it. T cells are effective at combating infection. Nevertheless, it can be difficult for them to distinguish between cancer cells and healthy cells. So that cancer cells can hide and remain unidentified. However, scientists discovered a way to make T cells recognize cancer cells. CAR T-cell therapy is an option for achieving this goal. In CAR T-cell therapies, T cells are extracted from the patient’s blood and modified in the laboratory by adding a gene for a receptor (called a chimeric antigen receptor or CAR), which enables the T cells to attach to a specific antigen on cancer cells. The patient is then administered the CAR T cells.
Even when other treatments have ceased to be effective, this type of treatment can be very helpful in the treatment of certain types of cancer.
CAR T-cell is recommended for those up to the age of 25 who have a type of leukaemia called B cell ALL. It will also be available to certain adults with one of the following lymphoma types:
- diffuse large B cell lymphoma
- Mediastinal B-cell lymphoma of origin
- The disease known as mantle cell lymphoma
Therefore, this treatment is only appropriate for a small number of children and adolescents and approximately 200 adults per year. It is not used as a treatment for other types of cancer in children or adults outside of clinical trials.
Types of CAR-T Cell Therapy
The US Food and Drug Administration (FDA) has authorized CAR T-cell therapies to treat certain lymphomas, leukemias, and multiple myeloma. CAR T-cell therapy is typically administered after other treatments have failed.
Existing CAR T-cell therapies include the following:
- Tisagenlecleucel, commonly referred to as tisa-cel (Kymriah)
- Axicabtagene ciloleucel, commonly referred to as axi-cel (Yescarta)
- Brexucabtagene autoleucel, commonly referred to as brexu-cel (Tecartus)
- Liso-cel, or lisocabtagene maraleucel, is another name for lisocabtagene maraleucel (Breyanzi)
- Ide-cel, or idecabtagene vicleucel, is also known as ide-cel (Abecma)
- Ciltacabtegene autoleucel, also known as cilta-cel, is a genetic material (Carvykti)
Numerous other CAR T-cell therapies (and similar types of treatment) are currently being investigated in clinical trials with the hope of treating additional types of cancer.
There are also experimental combined therapies between CAR-T cells and drugs. For example, for the treatment of pediatric glioma. Researchers have identified a never-before-tested cancer therapy: a combination therapy of an experimental drug (linsitinib) and CAR-T cells.
Preparation for CAR-T Cell Therapy
CAR T-cell therapy can take several weeks to complete.
Your medical team obtains a T cell sample from your blood. This procedure is known as apheresis. During this procedure, patients typically recline in a bed or chair. Two lines are required because blood is removed through one line, separated into red and white blood cells, and then reintroduced through the other line. Occasionally, a special type of line called a central venous catheter is used, which contains both lines.
During the procedure, the patient will be required to remain seated or lying down for two to three hours. During leukapheresis, calcium levels in the blood can sometimes drop, resulting in numbness, tingling, or muscle spasms. After removing the white blood cells, the T cells are isolated, transported to a laboratory, and modified by adding the gene for the specific chimeric antigen receptor (CAR). Thus, they become CAR T cells. These cells are then multiplied and grown in the laboratory. It can take several weeks to produce the large quantity of CAR T cells required for this treatment.
CAR-T Cell Therapy Procedure
Once there are sufficient cells, they are infused back into the bloodstream via a drip. The objective is for the CAR T-cells to then identify and destroy cancer cells. The modifications they undergo in the laboratory allow them to remain in the body for extended periods of time, recognizing and attacking specific cancer cells. Researchers continue to investigate how long they may remain in the body.
A few days prior to the infusion of CAR T-cells, the patient may receive chemotherapy to reduce the number of other immune cells. This increases the likelihood that the CAR T cells will become activated and fight the cancer. This chemotherapy is typically weak because CAR T cells are most effective when there are still cancer cells to attack. Once the CAR T cells begin binding with cancer cells, they begin to multiply and can assist in the destruction of additional cancer cells.
After CAR T-cell therapy, your doctors and nurses must closely monitor you for two weeks. You may choose to stay in the hospital. Or, the hospital may pay for you to stay in a hotel or other nearby residence. You will then attend day care every day. If you develop complications, you must remain in the hospital. Typically, your healthcare team will advise you to remain not far away from the center for up to 28 days after treatment.
CAR T-cell therapy can be extremely effective against certain types of difficult-to-treat cancers, but it can also cause severe or even life-threatening side effects. Due to this, it must be administered in a medical center with specialized training in its use, and patients must be closely monitored for several weeks after receiving CAR T cells.
Benefits of CAR-T Cell Therapy
Prior to the introduction of CAR T-cell therapies, the majority of B-cell cancer patients relied on chemotherapy and stem cell transplants. While the decision regarding a patient’s treatment should remain with the patient and her/his healthcare provider, CAR T-cell therapy does offer certain benefits that may make it an attractive option. Among these advantages are the potential for shorter treatment times, increased durability, and fewer side effects.
Treatment Duration
CART T-cell therapies require extremely brief treatment durations, typically a single infusion and less than two weeks of hospitalization.
Durability
While the longevity of CAR T-cell therapy is the subject of ongoing research, remission following CAR T-cell therapy appears to be long-lasting and typically lasts for several years in many patients. CAR T-cell therapy, like stem cell therapy, may be curative for at least some patients. As CAR T-cells persist in the body, they may continue to treat relapses long after the initial cancer has become inactive. Traditional chemotherapy, on the other hand, only kills cancer cells during and shortly after administration. Therefore, relapses necessitate restarting chemotherapy (or an alternative regimen) in order to produce an effect.
Safety
CAR T-cell therapies do not require aggressive chemotherapy, and patients receiving CAR T-cells do not typically require immunosuppression unless there is an increase in cytokines following infusion. This represents a significant safety advantage over stem cell transplantation and chemotherapy. Sometimes the adverse effects of stem cell transplants and chemotherapy are so severe that patients choose to forego treatment, which worsens their prognosis.
