Preliminary results from the Fred Hutchinson Cancer Research Center’s ongoing study into an experimental, ‘living’ immunotherapy found that it achieved sustained remission in 27 of 29 patients with advanced blood cancer. The results were presented at the recent annual meeting of the American Association for the Advancement of Science (AAAS 2016) in Washington, D.C.
Dr. Stanley Riddell, an immunotherapy researcher and oncologist at the Seattle research center who has studied the immune system’s role in disease treatment for over two decades, said the results were particularly impressive because some of the study’s participants were cancer relapse or treatment resistant cancer patients with poor survival odds.
He told the association that the progress seen finally places immunotherapy as a pillar of cancer therapy. Nonetheless, “Much like chemotherapy and radiotherapy, it’s not going to be a save-all,” he said, a press release reported, and some patients may need different approaches.
The Phase 1/2 trial, “Laboratory Treated T Cells in Treating Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia, Non-Hodgkin Lymphoma, or Acute Lymphoblastic Leukemia,” was designed to evaluate the safety and dosing of the latest version of experimental immunotherapy, in which a patient’s own T-cells are reprogrammed using genetically engineering to create T-cells that include synthetic molecules called chimeric antigen receptors, or CARs, that enable the T-cells to target and eliminate tumor cells. Participants in the trial, which began in 2013, included lymphoblastic leukemia, non-Hodgkin’s lymphoma and lymphocytic leukemia patients.
Since T-cells can multiply and replicate after being administered into patients, the therapy does not have to be delivered repeatedly. Researchers also found that introducing CARs into two specific subsets of T-cells could achieve more powerful and longer-lasting immune responses.
One arm of the study, led by Dr. David Maloney and Dr. Cameron Turtle, found that 27 of 29 acute lymphoblastic leukemia patients showed no evidence of cancer in their bone marrow after the infusions, Dr. Riddell reported. Nineteen out of the 30 non-Hodgkin lymphoma patients also reported partial or complete responses, and, in some patients, considerable amounts of tumor cells were eliminated after just one dose of the engineered T-cells.
The results have been submitted for publication in a scientific journal, he said.
The process will continue to be refined and Dr. Riddell has recently reformulated CAR T-cell therapy protocols to attempt a more effective approach and reduce the worst adverse effects, which can be severe and include neurological symptoms as well as ‘cytokine release syndrome,’ or drops in blood pressure and fever. In all participants, the risk of serious side effects was reduced if lower doses of T-cells were administered, even to the patients with the highest tumor burdens.