Attendees at this year’s annual meeting of the American Association for the Advancement of Science in Washington, D.C. were astounded by what they heard. Dr. Stan Riddell, of the Fred Hutchinson Cancer Research Center, shared his ongoing research study and clinical trial results on immunotherapy, an experimental cancer treatment. To say the results are extraordinary is an understatement.
Attendees at this year’s annual meeting of the American Association for the Advancement of Science in Washington, D.C. were astounded by what they heard. Dr. Stan Riddell, of the Fred Hutchinson Cancer Research Center, shared his ongoing research study and clinical trial results on immunotherapy, an experimental cancer treatment. To say the results are extraordinary is an understatement. In the first trial, conducted with patients who had acute lymphoblastic leukemia, a surprising 94% of participants had no symptoms at all after treatment. The second trial, conducted on patients with Non-Hodgkin lymphoma, saw 80% positive responses and over half of those became free of symptoms. Clinical trial success rates like these are unprecedented. But how does immunotherapy work, and why, as this recent article by Alex Perdikis points out, is there reason for hope?
How Immunotherapy Works
Using the body’s own immune system to fight cancer is not a new idea. How to encourage the body to fight cancer cells without destroying healthy cells is one of the problems researchers have come up against. Dr. Riddell has studied ways to strengthen the immune system to fight disease for more than 25 years. The present trial uses a form of immunotherapy that involves reprogramming the patient’s own T-cells to target and destroy cancer cells. T-cells, a type of white blood cell, are produced by the thymus gland and are a critical part of the body’s natural immune response. The patient’s T-cells are engineered with chimeric antigen receptors (CARs) and programmed to find and fight specific targets. The engineered T-cells are then infused back into the patient where they multiply on their own without repeated administration. The addition of CARs into two different T-cell subsets made the cancer fighting cells in the current clinical trial more potent, longer lasting, and more effective than previous iterations.
In one segment of Dr. Riddell’s study, 27 of the 29 patients who suffered from acute lymphoblastic leukemia had no trace of cancer left after T-cell infusions. In the group of 30 Non Hodgkin lymphoma patients, 19 experienced complete or partial responses. A single dose of engineered T-cells was enough to eliminate pounds of cancer in some study patients.
What makes the clinical trial results even more extraordinary is that most of the patients were considered terminal and not expected to survive more than a few months. Those same patients show no sign of disease today.
Almost There
Dr. Riddell cautions that, “Much like chemotherapy and radiotherapy, it’s not going to be a save-all.” Patients respond to treatment in different ways and multiple therapies may be required. Riddell also explains that, at this time, immunotherapy is a last ditch method to treat terminal patients after other treatments have failed.
Still, Dr. James Gallagher, BBC News website health editor, says that the field of immunotherapy is coming of age. Dr. Riddell and his team constantly refine the process to make treatments more effective and reduce side effects. Another challenge researchers are working on is how to use immunotherapy as an agent against solid tumors, such as those present in breast and lung cancers. Clearly, exciting new and innovative treatments are coming that lend hope to the fight against cancer.
