Bone marrow transplants are a possible treatment for chronic lymphocytic leukemia, a type of blood cancer, when it cannot be controlled by chemotherapy.
During one type of bone marrow transplant, stem cells are taken from the bone marrow of a healthy donor and injected into the blood of the patient. These cells can then transform into healthy blood cells and help fight the cancer.
According to a new study, vaccinating the patient with his own tumor cells, which have been exposed to radiation, may enhance the effect of such a transplant.
This study was conducted by Catherine J. Wu, MD, Associate Physician at the Dana-Farber Cancer Institute, Harvard Institutes of Medicine, Boston, Massachusetts.
The aim of this study was to test the effectiveness of tumor cell vaccination for chronic lymphocytic leukemia.
Chronic lymphocytic leukemia is a type of cancer that affects blood and bone marrow cells. The condition is more common in older adults.
One of the treatments for chronic lymphocytic leukemia includes transplanting stem cells taken from the bone marrow of a healthy donor.
During this study, 18 patients first received a stem cell bone marrow transplant from a donor. These patients then received the tumor cell vaccine.
The vaccine was developed by exposing patients' own tumor cells to radiation. Those cells were then injected back into the patient. According to this study, this stimulates the immune system to fight and destroy cancer cells.
The researchers found that around three years following vaccination, 13 of the 18 patients were in complete remission, which means they did not have any signs or symptoms of the cancer. The overall survival rate of vaccinated patients in the first two years was 88 percent and the progression-free survival rate was 82 percent.
Overall survival rates refer to the percent of treated patients alive after two years. Progression-free survival rates look at what percent of treated patients did not see their cancers worsen. This does not take into account any side effects that may have occurred due to the treatment.
According to the researchers, previous studies have demonstrated that with a bone marrow transplant alone, chronic lymphocytic leukemia patients had five year progression-free survival rates of 64 percent. This means that in 64 percent of the treated patients, the cancer did not worsen in five years.
Overall, the results suggest that vaccination using tumor cells might help control chronic lymphocytic leukemia after a stem cell bone marrow transplant.
This was an early stage clinical trial, so this tumor cell vaccine has not been approved by the FDA and is not yet available as a treatment option.
This study was published August 5 in the Journal of Clinical Investigation.
The study was funded by grants from the National Cancer Institute, the National Heart, Lung, and Blood Institute and the Leukemia and Lymphoma Society Translational Research Program.
The authors declared no conflicts of interest.