Leukemia Vaccine Looks Promising

Vaccine Boosts Body's Attack on Cancer Cells

From the WebMD Archives

Feb. 17, 2005 - An experimental vaccine could provide a new treatment for people with chronic myeloid leukemia (CML), a new study shows.

Not only does the vaccine boost the body's immune system to fight leukemia, but it also helps get rid of the underlying cause of the leukemia. Currently, this can only be done with a bone marrow transplant.

This could help lead to a cure for CML, which affects about 4,500 Americans each year.

In chronic myeloid leukemia, overproduction of an abnormal protein leads to very high numbers of cancerous white blood cells.

Current treatment, such as Gleevec, targets this abnormal protein. Although Gleevec normally gets rid of any detectable cancer cells, the cancer-causing protein still remains.

And that's what researcher Monica Bocchia, MD, a hematologist with Siena University in Siena, Italy, wanted to address. Her study appears in this week's issue of The Lancet.

The researchers tested the use of a cancer vaccine to help trigger the body's immune system to recognize and attack cells with the CML protein.

Cancer vaccines are not vaccines in the way that most people think of vaccines. Unlike most vaccines, which help prevent diseases, cancer vaccines are added to treatment in someone who already has cancer.

In her study, she and her colleagues recruited 16 patients with chronic myeloid leukemia. All had received treatment with either 12 months of Gleevec or 24 months of interferon alpha, another CML treatment. The patients' disease was stable.

Each was given six injections two weeks apart. The vaccine actually contained the abnormal protein itself. This stimulates the immune system to launch an attack against cancerous cells containing the abnormal protein.

Nine Gleevec-treated patients showed progressive reduction of their remaining disease. Five patients went into complete remission; three had no evidence that the CML protein was still lurking. All but one of the six interferon-alpha-treated patients had a good response; two went into complete remission.

The researchers say the vaccine was effective at stimulating an immune system attack against the cancer cells with the abnormal protein.

They say adding the vaccine to current CML treatment may help get rid of remaining cancer cells.

In addition, the vaccine was able to get rid of the cancer-causing protein -- a sign that the CML has been cured.

The vaccine is experimental and not yet available to the public.