‘Personalized’ Vaccines Help Treat Chronic Leukemia
Friday, August 9, 2013
Patients with advanced chronic lymphocytic leukemia (CLL) often receive donor transplants that effectively “reboot” their own immune defenses, which then attack and potentially cure the hard-to-treat disease. However, these patients have a high rate of relapse, and the transplanted immune cells may also harm normal tissues, causing graft-versus-host disease (GVHD).
Now, scientists at Harvard-affiliated Dana-Farber Cancer Institutereport in the Journal of Clinical Investigation that they observed a strong and selective immune response in some patients who received, shortly after the transplant, several doses of a “personalized” tumor vaccine composed of their own inactivated leukemia cells combined with an immune stimulant, granulocyte-macrophage colony-stimulating factor (GM-CSF). Thus the vaccine boosted the power of the transplanted immune system’s ability to attack the cancer— known as the graft-versus-leukemia (GvL) effect.
“Our studies suggest that autologous tumor cell vaccination is an effective strategy to advance long-term leukemia control” following transplants from donors, says senior author Catherine Wu, a Harvard Medical School associate professsor of medicine. “Although this was a phase 1 study and not powered to look at questions of clinical efficacy, we did see promising clinical activity.”
There are few treatment options for advanced CLL. Standard transplants, which involve powerful doses of pre-transplant chemotherapy to wipe out as much of the leukemia as possible, have proven too toxic for older patients and those with co-existing diseases. Over the past decade, researchers have developed reduced-intensity conditioning (RIC) regimens, using lower chemotherapy doses that are more tolerable but rely entirely on the activity of the transplanted immune cells to battle the leukemia. Usually this is insufficient to keep the cancer at bay long-term and the disease progresses.
- Health Care