In early February 2022, researchers announced that two patients who had chronic lymphocytic leukemia (CLL) are still cancer-free 10 years later after previously undergoing CAR T-cell therapy; the news made headlines around the world and gave hope to cancer facilities everywhere, but what exactly does this treatment entail, and could it have the potential to help patients with other types of cancers?
Defining CAR T-cell Therapy
Chimeric antigen receptor therapy (CAR T-cell therapy) is a type of cancer treatment that utilizes T-cells, white blood cells that are vital to our immune system. A sample of a patient’s T-cells are taken to the lab, where some genes in said cells are then modified to ensure that they can better find proteins on cancer cells (antigens). During the process, the chimeric antigen receptor (CAR) for the type of cancer the patient has is added to the T-cells. All-in-all, this procedure takes about two weeks to prepare. Once the changed cells are ready to battle cancer cells, they are returned into the patient’s body via an IV (infusion).
Thus far, the treatment has been approved by the Food and Drug Administration (FDA) for a select number of cancers, including acute lymphocytic leukemia (ALL), non-Hodgkins lymphoma, and multiple myeloma; it has not yet been approved for CLL. However, like any other treatment, CAR T -cell therapy does have side effects, such as fever, chills, vomiting, dizziness, agitation, and seizures. As such, it is usually administered to patients at a medical center that is specifically trained to provide it.
A Study Reveals a Breakthrough
In the abovementioned study, the researchers observed 3 CLL patients that received the therapy as part of a clinical trial at the … Cancer Center and the Perelman School of Medicine at the University of Pennsylvania in Philadelphia. CLL is one of the most common leukemias in adults and starts in the bone marrow, before moving into the blood.
Co-author of the study and immunologist J. Joseph Melenhors PhD reported that two of the patients went into complete remission after undergoing the treatment in 2010. Over time, the researchers continued to analyze the CAR T-cells and found that a decade on, the cells were still finding and eliminating cancer cells; additionally, no leukemia cells were found.
Additionally, when the patients first began the treatment, their immune responses were dominated by CD8+ cells which directly targets cancer cells. Subsequently, unique cytotoxic (cancer-killing) CD4+ helper T-cells dominated the immune response of each patient and continued attacking the cancer cells, thus maintaining the cancer remission.
Essentially, this is a breakthrough finding; the patients were diagnosed with CLL 20-30 years ago, and multiple therapies failed. Thanks to CAR T-cell therapy, they can now go about their daily lives and find new hobbies.
The Big Question: Could This be a Possible Treatment for Other Cancers?
While CAR T-cell therapy can give a patient long-lasting immunity against some cancers, it unfortunately does not work for everyone or every type of cancer, although researchers in this field are now more hopeful and are studying whether similar strategies and treatments can address other types of blood cancers.
Another issue with the therapy is whether the treatment and strategy can deal with solid tumors, which are much more complicated than liquid tumors (blood cancers). In fact, several types of cancers do produce these solid tumors, which are surrounded by proteins and other cells that the CAR T-cells are unable to reach an attack. As such, other cellular therapies are currently being studied as alternatives:
- T-Cell Receptor (TCR) Therapy: This treatment harvests T-cells from patients and engineers them to target specific proteins within a cancer cell; the modified cells are then infused back into patients;
- Tumor-infiltrating Lymphocyte (TIL) Therapy: T-cells are harvested from patients and cultured in a lab with a substance produced by lymphocytes (lymphokines), the modified cells are then infused back into patients to attack tumor cells;
- Natural Killer (NK) Cell Therapy: Donor lymphocytes are used to attack abnormal cells.
The bottom line? While CAR T-cell therapy won’t work for everyone, these new findings serve as inspiration for researchers to refer to this strategy and treatment and search for ways to use them in a different form to tackle other cancers.
Source: https://www.verywellhealth.com/2-patients-cancer-free-after-immunotherapy-treatment-5218255
