Adjuvant breast cancer vaccine improves disease specific survival of breast cancer patients with depressed lymphocyte immunity.

Purpose: Beginning in 1995 breast cancer patients were vaccinated in the adjuvant setting with an autologous, allogeneic whole cell vaccine to evaluate the effect on host lymphocyte immunity and disease specific survival.

Methods: The breast cancer patients had host lymphocyte immunity against tumor associated antigens evaluated by a Lymphocyte Blastogenesis Assay (LBA) before vaccination. Thirty-seven patients with depressed immunity were vaccinated in the adjuvant setting. Patients were given six intradermal injections (three weekly followed by three monthly). Ten weeks after the last injection the LBA was repeated.

Results: Some patients experienced slight pain and swelling at the injection site with slight chills and fever, but there were no severe toxicities. The vaccinated patients had a mean follow-up of 12.7 years with mean follow-up of 8.9 and 9.2 years for the patients with normal and depressed immunity, respectively, in the historic control. The 10 year survival was 95% (20 of 21 patients) in the normal immunity historic control, 59% (33 of 56 patients) in the depressed immunity historic control and 89% (33 of 37 patients) in the patients with depressed immunity that were vaccinated in the present clinical trial. The disease specific survival of the vaccinated patients with depressed immunity in this trial is significantly greater than that of the historic controls of unvaccinated patients with depressed immunity to their tumor associated antigens.

Conclusion: This study confirms the importance of maintaining good host lymphocyte immunity after completion of standard therapy and validates the value of cancer immunotherapy in the adjuvant setting.