Clinical outcome of breast and ovarian cancer patients treated with high-dose chemotherapy, autologous stem cell rescue and THERATOPE (R) STn-KLH cancer vaccine

The purpose of this study was to evaluate the toxicity and potential effica cy of administering the THERATOPE(R) STn-KLH cancer vaccine to ovarian and breast cancer patients after an autologous stem cell transplant. Forty pati ents (11 high-risk stage II/III breast cancer, 22 stage IV breast cancer, a nd seven stage III/IV ovarian cancer patients) were treated with high-dose chemotherapy followed by autologous/syngeneic stem cell rescue and vaccinat ion with THERATOPE STn-KLH (Sialyl-Tn-KLH with Detox-B Stable Emulsion). Ea ch patient was scheduled to receive a total of five vaccinations beginning on days 30-151 after stem cell infusion. The vaccine was well tolerated. In duration and erythema at the site of injection were the most common side-ef fects. When one compares the outcome of patients vaccinated with 66 breast and ovarian cancer patients who were not, following risk-adjustment analysi s, vaccinated patients appeared more likely to survive (P = 0.07) and less likely to relapse (P = 0.10). Vaccinated patients with the greatest specifi c lytic activity against STn+OVCAR tumor cells relative to nonspecific kill ing of Daudi cells tended to remain in remission longer than patients who d isplayed less specific immune activity (P = 0.057). We conclude that the TH ERATOPE STn-KLH cancer vaccine is well tolerated in breast and ovarian canc er patients after autologous transplant and, while not statistically signif icant, the trends in data support the concept that THERATOPE vaccine may de crease the risk for relapse and death and thus warrants further study.