Exciting results from an immunotherapy trial of patients with advanced blood cancers were announced during the American Association for the Advancement of Science Annual Meeting in Washington, DC. Stanley Riddell, MD, lead immunotherapy researcher and oncologist from Fred Hutchinson Cancer Research Center, shared the results as an update on new adoptive T-cell therapies.
The trial was designed to test the safety of an experimental immunotherapy in which a patient’s own T cells are reprogrammed. Reprogramming involves genetically engineering the T cells with synthetic molecules called chimeric antigen receptors (CAR), which help to target and destroy tumor cells. Clinical trial participants included patients with acute lymphoblastic leukemia (ALL), non-Hodgkin lymphoma (NHL), and chronic lymphocytic leukemia (CLL).
Twenty-seven out of 29 patients with ALL received a “living” immunotherapy treatment as part of one arm of the clinical trial and showed no trace of disease in their bone marrow following the infusions. Nineteen out of 30 patients with NHL experienced partial or complete responses. During his presentation, Dr. Riddell showed examples of patients whose tumors disappeared from imaging scans within weeks of the infusion, literally pounds of tumors—gone.
The patients in this small study experienced sustained remissions, according to preliminary results of the ongoing study. Some of the patients in the trial, which began in 2013, were not expected to survive for more than a few months because their disease had relapsed or became resistant to other treatments, said Dr. Riddell. Today, there is no sign of disease in these patients.
But, Dr. Riddell cautioned in a Fred Hutch news release, “Much like chemotherapy and radiotherapy, it’s not going to be a save-all.” Some patients may require additional or different treatments.
Recently, they revised their CAR T-cell therapy protocols to try to reduce severe side effects such as neurological symptoms and cytokine release syndrome (fevers, nausea, hypotension, and dyspnea)—especially in those patients with the highest tumor burdens. Giving the lowest doses of T cells to the patients with the highest tumor burdens reduced the risks of serious side effects.
Dr. Riddell and his team continue to refine ways to harness the human immune system to overcome cancer and other diseases. Researchers at his lab and other labs at Fred Hutch are developing the next generation of engineered T cells, which are expected to be safer.