Dec. 10, 2007 -- An experimental new leukemia treatment that boosts the body's own immune system to fight disease may prolong life.
Early clinical trials show some people who responded to the vaccine experienced event-free survival that was three times longer than those who didn't respond to the leukemia treatment.
But researchers are quick to point out that this is not a leukemia cure, as only about half of the people with active leukemia in the study experienced an immune response to the vaccine. Even so, researchers were impressed by these early results and plan further clinical trials to evaluate the effectiveness of this new approach to leukemia treatment.
"We did not expect dramatic responses in this clinical trial, and were pleasantly surprised to see the clinical responses and improved event-free survival," says researcher Muzaffar Qazilbash, MD, in a news release. Qazilbash is associate professor in the department of stem cell transplantation and cellular therapy at the University of Texas M.D. Anderson Cancer Center.
The results of the study were presented this week at the American Society of Hematology conference.
New Approach in Leukemia Treatment
The phase I/II clinical trial evaluated the effect and safety of the leukemia vaccine in 66 people with acute myeloid leukemia over three years of follow-up. Of the 53 patients with active leukemia, 25 (47%) had an immune response to the treatment (as determined by lab tests) and 28 did not.
Those that had an immune response experienced a longer period of event-free survival from their disease during the study, an average of 8.7 months compared with 2.4 months among those who didn't respond to the vaccine.
The leukemia vaccine is derived from two leukemia-associated antigens and works by stimulating the immune system to selectively kill leukemia cells.
"Immunotherapy works best for low level of disease," says Qazilbash. "So patients with low leukemia burden may get the maximum benefit."