PSA-Based Vaccine and Radiotherapy to Treat Localized Prostate Cancer
Status:
Completed
Trial end date:
2005-12-22
Target enrollment:
Participant gender:
Summary
This study will test the ability of an experimental vaccine to increase the number of
tumor-fighting immune cells (lymphocytes) in patients with localized prostate cancer and
prevent the disease from recurring following radiation therapy. The vaccine is intended to
stimulate lymphocytes to target and attack cells containing a protein called prostate
specific antigen, or PSA. It is composed of the following parts:
- rV-PSA: Vaccinia virus plus human DNA that produces PSA (prostate specific antigen)
- rV-B7.1: Vaccinia virus plus human DNA that produces B7.1 (a protein that helps guide
immune cells to their targets)
- rF-PSA: Fowlpox virus plus human DNA that produces PSA
- GM-CSF: Drug that boosts the immune system.
- IL-2: Drug that boosts the immune system.
Patients 18 years of age and older with prostate cancer confined to the prostate who have
received a smallpox vaccine sometime in the past and who do not have a history of allergy to
eggs may be eligible for this study. Candidates are screened with a complete medical history
and physical examination, blood tests, and skin tests (similar to those for allergies or
tuberculosis) to assess immune function.
Participants are randomly assigned to receive one of the following three treatments: Group 1
- standard radiation therapy plus the experimental vaccine; Group 2 - standard radiation
therapy without the vaccine; Group 3 - standard radiation therapy with the vaccine, but with
a different dose of IL-2 from Group 1.
Patients in the vaccine groups receive injections in the arm or thigh in 28-day treatment
cycles, as follows:
- GM-CSF: Days 1 through 4 of the first week
- IL-2 5: for Group 1, 5 days in the second week of each cycle; for Group 3, 14 days
beginning in the second week of each cycle
- rV-PSA and rV-B7.1: Day 2 of the first cycle only
- rF-PSA (booster shots): Every 28 days, beginning day 2 of the second cycle (i.e., days
30, 58, 86, etc.)
Treatment continues for eight cycles unless serious side effects develop, PSA levels rise
significantly, or the doctors feel there is no reason to continue therapy.
All patients undergo radiation therapy and possibly hormone therapy, if indicated. Blood
samples are drawn once a week for the first month and then once every 4 weeks to monitor
safety. After treatment ends, patients are followed with examinations and blood tests every 3
months for the first 2 years and then every 6 months until the doctors determine follow-up is
no longer needed or the cancer returns.
All patients have HLA tissue typing at the beginning of the study. Those who are type HLA-A2
are asked to have additional procedures for studying the immune response that can be done
only with this tissue type. This involves collecting blood samples before treatment begins,
every 4 weeks during treatment, once after cycle 2, and once 4 months after the eighth
vaccine. They also undergo four leukapheresis procedures for collecting white blood cells.
For leukapheresis, blood is collected through a needle in an arm vein, similar to donating a
unit of blood. The blood flows through a machine that separates it into its components. The
white cells are removed, and the red cells, platelets and plasma are returned to the body,
either through the same needle or through a needle in the other arm.