When you think about cancer treatment, you may immediately envision chemotherapy, which acts to stop the growth and reproduction of tumor cells. While chemotherapy has been very successful at treating many forms of cancer, it isn’t without possible complications. Sometimes, in the process of targeting cancer cells, chemotherapy can also damage or kill healthy cells.
Scientists may have found a way to get around that by using a new method of treatment that works, not by targeting cancer cells, but instead by targeting the mechanics of T cells, the body’s natural immune response to cancer. The treatment, which uses drugs known as checkpoint inhibitors, has been in the news recently for its growing rate of success in treating things like melanoma and lung cancer.
T Cells and Cancer
T Cells are a type of white blood cell that the immune system sends out in response to a perceived threat (like infection or disease). In order for a T cell to be successful, it needs to be able to recognize the difference between normal, healthy cells, and those that need to be attacked. These cells rely on “checkpoints” which are molecules that can be found on certain immune cells. Depending on what the T cell finds it will either activate or inactive the cell as part of the immune response.
When T cells encounter cancer cells, they can sometimes be tricked into believing they’re normal, healthy cells. That’s something doctors are using checkpoint inhibitors to change. The inhibitors work by releasing the breaks on the T cells’ immune response and allowing them to get back to work on finding and killing cancer cells.
Success Rooted in T Cell Presence
Checkpoint inhibitors may be having great success with some forms of cancer, but that doesn’t mean that they will be as effective with others. Elizabeth Mittendorf, MD, Ph.D., the Director of the Breast Immuno-Oncology Program at the Dana-Farber/Brigham and Women’s Cancer Center, explains to Parentology the treatment is only beneficial in cancers with a high T cell count. “If we consider that checkpoint inhibitors work by taking the brakes off of T cells, generally we would think that they work best in tumors (such as melanoma and lung cancer) that have the most T cells in them.” This makes them a less effective treatment for some tumors that are found in breast cancer, where there are fewer T cells.
Those receiving treatment with checkpoint inhibitors will mainly be doing so through intravenous (IV) applications, however, Cicely K. Johnson, Ph.D., explains to Parentology there’s an oral version of the drug currently awaiting approval by the Food and Drug Administration (FDA). Anyone interested in seeing if this type of treatment would be a good fit for their cancer diagnosis should check with their doctor or oncologist.
There are certain things that will make patients good candidates for the use of checkpoint inhibitors, and Johnson says ultimately your medical team will be the best ones to help you make that decision.
A Bright Future For Checkpoint Inhibitors
Mittendorf believes checkpoint inhibitors are just the beginning, explaining there’s approval for using it on patients with metastatic triple-negative breast cancer (TNBC), but they don’t yet know enough to determine the biomarkers for success. She says there’s a lot to learn, but there are many opportunities for studying the use of the treatment in the early stages of the disease to determine how to make other breast cancer subtypes (like hormone receptor-positive or HER2 positive) susceptible to checkpoint blockade.