New Immunotherapy Could Save our 39th President
by Paul Karrell
An inspiring man and former president of the United States, Jimmy Carter, publicly revealed on August 20, 2015 that he had been diagnosed with melanoma, which is an advanced form of skin cancer that begins in the cells that give skin its pigment, called melanocytes. Developing typically near the surface of the skin, this cancer has the ability to spread to virtually anywhere in the body through the blood stream and, as in Carter’s case, metastasize to the brain. Since most skin cancers are visible on the surface of the skin, tumors can be usually removed through surgery during the early stages of melanoma. But if ignored, internal complications can occur.
Only a year ago, the average survival time for a person diagnosed with advanced stage melanoma would have been between six to 10 months. Now, however, there is hope for a far longer life expectancy for Carter due to the development of anti-PD-1 immunotherapy, a specific form of which called Pembrolizumab, will be given to the former president in the form of an injection. The drug was developed by the American pharmaceutical company Merck in 2006 and approved by the U.S. Food and Drug Administration (FDA) in 2014.
A closer look into how immunotherapy works is necessary to understand just how revolutionary this is. Carter has four different spots on his brain where the melanoma has metastasized. According to our understanding of oncology, both noncancerous and cancerous cells have receptors on their outer membranes that signal “Do not destroy me” to white blood cells, which are normally recruited by the immune system in order to detect and destroy cancerous cells, as well as other substances that are deemed to be foreign or dangerous by the body. While this signal prevents white blood cells, which are also called leukocytes, from destroying healthy, normal cells, it also causes the immune system to pass over cancerous cells, thus allowing a tumor to grow.
However, the immunotherapy drug anti-PD-1 has a clever way of seeing past this. PD-1 is a receptor on the surface of T-cells, a type of white blood cell, that when bound to by the cell’s ligand, specifically PD-L1, causes a series of chemical reactions that tell the T-cell to stop destroying foreign, or in Carter’s case, cancerous cells. To explain, a ligand is a molecule that when bound to by another specific molecule, triggers some type of cellular response, which in this case, is an immune response to destroy cancer cells. Pembrolizumab, or anti PD-1, works by blocking this PD-1 receptor on T-cells. As the PD-1 receptor is no longer bound to its ligand, the T-cell does not receive a signal to cease functioning and instead continues to destroy cancerous cells. In short, the drug works as a “brake release” on the immune system.
Despite having some slight side effects, including fatigue, aching and itching, which vary depending on the patient, the drug is quite tolerable for individuals. Along with immunotherapy, Carter will also be treated with something called focused radiation over the next couple of months. The procedure is a type of therapy that works well on small cancerous masses. It involves aiming a small and precise beam of radiation at a well-defined tumor. This barrage of electromagnetism is what destroys the cancerous cells. The tumor itself is located through magnetic resonance imaging (MRI) scans that delineate, through computer analysis, exactly where to aim the beams of radiation. Through focused radiation, physicians are able to accurately destroy cancer cells with minimal damage to surrounding tissue. Despite the advanced stage that Carter’s melanoma has reached, with the great amount of treatments he will be undergoing, there is reason to be optimistic.
As with any cancer, melanoma is a terrifying disease to be confronted with, and Carter’s story in dealing with it is nothing short of inspiring. A man who has witnessed the deaths of his father, mother and three siblings, all due to cancer, Carter initially believed that he only had a few weeks to live when first diagnosed. Despite receiving such devastating news, Carter did not fall victim to despair and declared that, "I'm perfectly at ease with whatever comes … I’m ready for anything. I'm looking forward to a new adventure.” Carter also expressed full trust in the medical team of Emory University in treating him.
It is a blessing that Carter has, as his oncologist put it, the “vanguard of cancer treatment” to assist his recovery, because he has a lot to live for. He has established the philanthropic organization the Carter Center with the mission to “prevent and resolve conflicts, enhance freedom and democracy, and improve health,” as well as been highly active in a myriad of other charitable organizations. This man has unarguably gone above and beyond what is expected of a president following the end of his term in office and has a far more hopeful prognosis than what would have been expected only a year before.
These treatments of immunotherapy and focused radiation treatment offer a ray of hope in the battle against melanoma and cancer as a whole. To illustrate just how fast medical research has come, CBS News medical contributor, Dr. David Agus, stated in an interview, "Several years ago if he [Carter] had been diagnosed with this, the prognosis would have been dismal and we probably wouldn't have treated him at all … But in today's world with this immunotherapy he's getting … the prognosis is actually somewhat optimistic.”
Carter’s struggle against melanoma is not a battle won just yet, but these advances in modern medicine demonstrate that there are still plenty of innovative treatments waiting to be discovered, and that research in the field of cancer treatment changes lives everyday and prolongs the ones that shape our world.