Advances in immunotherapy research to combat cancer has provided unprecedented treatment success due to the discoveries of two different Nobel Laureates, Dr. James P. Allison (U.S.) and Dr. Tasuku Honjo (Japan). Working independently, they each discovered immune system proteins that are important in self-tolerance and that can be harnessed to kill cancer cells. Checkpoint molecules prevent the immune system from killing the body’s own healthy cells. When checkpoint molecules are encountered by T cells, the cells bearing these molecules are spared attack. However, some cancer cells wear checkpoint molecules, acting as imposters of normal cells to evade attack by T cells.
Dr. Allison discovered the checkpoint molecule cytotoxic T lymphocyte–associated protein 4 (CTLA-4), and Dr. Honjo discovered the programmed cell death protein 1 (PD-1). Based on the Nobel Laureates’ findings, drugs that work as checkpoint inhibitors have been developed that allow T cells to recognize and attack cancer cells. Various checkpoint inhibitors are available including, PD-1 inhibitors pembrolizumab (Keytruda®), nivolumab (Opdivo®) and atezolizumab (Tenectriq®), and the CTLA-4 inhibitor Ipilimumab (Yervoy®).
Notable examples of patients successfully treated with checkpoint inhibitors include former President Jimmy Carter who received the PD-1 checkpoint inhibitor Keytruda in 2015 for metastatic melanoma. By his follow-up several months later, there was no cancer found. Another example is that of a woman who was dying of melanoma but found to be free of the cancer after 4 treatments with a checkpoint inhibitor developed by Dr. Allison. This and other positive patient outcomes were possible with the checkpoint inhibitor immunotherapy strategy.
Before the discoveries, the only options for cancer therapy were chemotherapy, radiotherapy, surgery, and hormonal treatments. Now, there is a new immunotherapy paradigm that is offering successful patient outcomes. Checkpoint inhibitors do not work for everyone, and there is still risk of severe side effects including death. However, continued research can help unveil more knowledge of immune checkpoints and other mechanisms related to the action of T cells in cancer treatment, as well as contribute to the development of immunotherapies that can treat more types of cancer without debilitating and serious side effects.
Check out HemaCare’s product offerings, including T cells to support your immunotherapy research.
Reference: 2018 Nobel Prize in Medicine Awarded to 2 Cancer Immunotherapy Researchers. (2018). Nytimes.com. Retrieved 19 November 2018, from https://www.nytimes.com/2018/10/01/health/nobel-prize-medicine.html