Following a stem cell transplant with a cancer vaccine just weeks later appears to reduce complications for patients with a particularly hard-to-treat form of acute myeloid leukemia while significantly improving the immune system's ability to fight the disease. And transplant rejection rates for the combo approach were no higher than what patients typically experience when getting the transplant alone.
To make the vaccine, cancerous tissue was extracted from patients and cells were genetically altered to produce a protein called GM-CSF. When these modified cells were injected into patients as a vaccine, the cells began pumping out GM-CSF. "Just as a matador's cape provokes the bull to attack, GM-CSF spurred the immune system to attack cancer cells throughout the body."
All of the patients who received even a single vaccination had a better survival rate than people with these diseases customarily have. Of the 10 who received the entire vaccine course, nine are alive and in full remission up to four years after treatment. And researchers say the new study underscores how important combo therapies can be for cancer patients.
"It usually takes several months following a transplant for the new tissue to take root in the bone marrow and fully reconstitute the blood supply," said Robert Soiffer, a professor at Harvard Medical School. "The period while that reconstitution is taking place is special. The initial chemotherapy has depleted much of the patient's immune system, and the body is trying to restore its previous state of function. That 'unsettled' condition seems to be a very opportune moment for an intervention such as a cancer vaccine."
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