SAN FRANCISCO, FEBRUARY 17: An innovative treatment for prostate
cancer that uses a person's own immune system has been found for the
first time to prolong the lives of patients with the disease, the most
common form of cancer among men.

The study led by researchers at the University of California at San
Francisco found that the cancer ''vaccine'' increased survival,
on average, by 4.5 months among men with advanced prostate cancer who
no longer responded to other treatments. The results are being made
public at a prostate cancer symposium in Orlando, Florida.

Although the benefit seems moderate, doctors said it is a significant
improvement for patients with few options and little hope. They also
said it represents an important validation for cancer vaccines, a new
approach that doesn't prevent cancer -- the classic approach of a
vaccine -- but instead rallies the immune system to fight the
disease.

Cancer vaccines are emerging as a promising fourth way to combat cancer
that could complement the existing treatments of chemotherapy,
radiation and surgery. Vaccines are particularly appealing to patients
because they don't have the debilitating side effects associated with
chemotherapy and radiation.

''This is really the very first study that has shown a survival
advantage for any (cancer) vaccine,'' said Dr. Eric J. Small, a
UCSF oncologist who was the principal investigator of the study.
''What that does for the field is very exciting. It tells us that
we're on the verge of a new era of therapeutics that will be
targeting the immune system.''

Small will present the results of the Phase III clinical study Saturday
at the Multidisciplinary Prostate Cancer Symposium in Orlando.

Prostate cancer is the most common type of cancer among men, with an
estimated 232,090 cases diagnosed each year. More than 30,300 men die
annually of the disease, making it the second-leading cause of cancer
deaths among men after lung cancer.

The study involved 127 men with prostate cancer that had spread to
their bones and who no longer responded to hormone therapy, the
conventional treatment, but who had not yet experienced pain from the
disease. Patients were given either a placebo or the vaccine --
three doses over a six-week period -- and were followed for three
years. Patients who received the vaccine survived, on average, for 25.9
months, compared with 21.4 months for men who received a placebo, a
nearly 20 percent survival improvement. After three years, three times
as many vaccine patients (34 per cent) were still alive, compared with
the placebo group (11 per cent).