Retrospective analysis of the clinical efficacy of a dendritic cell-based cancer vaccine in patients with advanced or recurrent breast cancer

Abstract Objectives Tumor-specific cytotoxic T lymphocytes can be efficiently activated in vivo by dendritic cell (DC)-based vaccination. This trial assessed the clinical efficacy and toxicity of DC-based immunotherapy in patients with advanced breast carcinoma. Methods DC-based immunotherapy (DC vaccine alone or DC vaccine plus lymphokine-activated natural killer (NK) cell therapy) was administered to 26 patients with unresectable breast carcinoma refractory to standard treatment. After leukapheresis, DCs were generated from CD14 + monocytes by 6 day cultivation with GM-CSF and IL-4. DCs were then matured by OK-432 treatment and pulsed with cancer-associated antigens, such as WT1, MUC1, and HER2. DCs were administered 5–8 times intradermally at 14-day intervals. Results Twenty-six patients with performance status (PS) of 0 ( n  = 4), 1 ( n  = 14), 2 ( n  = 4) and 3 ( n  = 4), and a median age of 55.5 years were eligible for this study. Of the 26 patients, DC vaccine was administered in combination with chemotherapy in 50%. Best response by RECIST, 1 patient showed a complete response (CR), 14 had partial response (PR), and 17 had stable disease (SD). The response ratio was 15.4％. None of the patients experienced adverse events of grade 2 or higher during the treatment period. The median overall survival (OS) time was 552.9 days (95% CI; 402.6–703.3 days). Log-rank test analysis demonstrated that the better PS groups (i.e., 0, 1) had significantly better survival times compared to those in poorer PS groups (i.e., 2, 3) (MST, 709.6 days, 95% CI, 502.2–917.0; vs. 200.4 days, 95% CI, 0–410.7; P Conclusion DC vaccine-based immunotherapy demonstrates promising OS times and tolerable toxicities in the setting of breast carcinoma. A full risk/benefit analysis of DC-based vaccines in patients with metastatic breast carcinoma will be determined in a future phase II trial.