Trial cancer vaccine uses deceit tactics

Although cancer vaccines haven’t been approved by the Food and Drug Administration, several are being tested – and researchers hope one or more will be widely available in a few years.

Last week, doctors announced results of the first trial showing a cancer vaccine can extend lives. The Provenge prostate cancer vaccine, made by Seattle-based Dendreon Corp., reportedly helped men with advanced disease who no longer benefit from standard hormone therapy live four months longer than patients who got placebos.

Experts say they’re excited about newer technologies, still in early tests, that one day may work even better than Provenge.

Persuading the immune system to attack cancer cells has proved challenging, says David Avigan of Beth Israel Deaconess Medical Center in Boston. Cancer cells are made from the body’s own tissues – something the immune system is programmed not to attack, he says.

Tumors also produce substances that tell the immune system to stand down.

Vaccines such as Provenge combine immune cells taken from the patient’s own body with a marker, or antigen, often found on prostate cancer cells.