E7897 – Trial Results Summary for Patients

Title

PSA Vaccine Therapy to Treat Advanced Prostate Cancer (A Phase II Trial)

Sponsor

Eastern Cooperative Oncology Group through the NCI-sponsored Cancer Cooperative Group Program

Purpose of the Study

To evaluate the effectiveness of three different prostate-specific antigen (PSA) vaccine treatments in men with advanced prostate cancer. Vaccination with one or two different substances were studied to see if and to what extent they activate an immune response that may help the body fight the growth of tumor cells.

Results

All three vaccine treatments were well tolerated. There was no increase in PSA level in 45.3 percent of men in the study after 19.1 months. Cancer did not progress in 78.1 percent of participants during that time. Additional clinical trials of PSA vaccines in the treatment of advanced prostate cancer are supported by these results. The results of a follow-up review of the trial after four years further supported additional studies.

Conclusion

Based on these data two follow-up clinical trials have been developed. In the E9802 trial men with rising PSA after completing initial therapy for localized prostate cancer (similar to the patient population in E7897) will be vaccinated with a prim-boost poxvirus vaccine and will begin hormone therapy in the face of biochemical progression. This trial will attempt to determine the effects of combining vaccine and standard hormonal therapy in men with advanced prostate cancer. A randomized Phase III clinical trial comparing vaccine to placebo vaccine in men with androgen independent advanced prostate cancer (E1805) has also been planned. These studies are based on the initial results of E7897 and will contribute to our understanding of how best to administer vaccines in relation to hormonal manipulation and will determine clinical outcomes in a larger randomized clinical trial design.

Start Date

August 1999

Stop Date

September 2000

Number of Participating Patients

70

Eligibility Requirements

Study participants had been diagnosed with prostate cancer and had completed cancer treatment. Their levels of PSA had increased following treatment, indicating a high probability of a recurrence of cancer.

Study Design

Participants were randomly assigned to one of three treatment groups. One group received four injections of a vaccine called fowlpox-PSA alone. Another group received three injections of fowlpox-PSA followed by one of another vaccine called vaccinia-PSA. The third group received a single injection of vaccinia-PSA vaccine followed by three injections of fowlpox-PSA vaccine. Treatment was given every six weeks.

Side Effects

Most side effects were mild to moderate, including mild to moderate skin irritation at the injection site, muscle aches, and elevated blood sugar levels.

Additional Information at ClinicalTrials.gov

NCT00003871