e13050 Background: To develop therapeutic cancer vaccine, we conducted a phase II study of personalized peptide vaccine (PPV) for refractory breast cancer patients. Methods: Thirty-four refractory breast cancer patients, including 8 triple negative (TN) cases, were enrolled to this study. A maximum of four HLA-class IA (A2, A3s, A24, A26)-matched peptides showing higher antigen-specific IgG responses were administered. Inflammatory markers, cytokines, and peptide-specific CTL and IgG responses were examined before and after vaccination to identify prognostic factors for overall survival (OS). Results: No vaccine-related severe adverse events were observed. Median numbers of preceding chemo- and/or hormone therapy regimens and median treatment duration from the recurrence to the vaccination were 2 regimens and 37 months, respectively. Three patients did not complete the 6th vaccination because of rapid disease progression. CTL or IgG boosting by PPV was observed in 16 or 18 of 31 patients at the time of 6th vaccination. IgG boosting was observed in all 24 patients tested at 12th vaccination. Median survival time of 31 patients receiving > 6th vaccination after the vaccination was 474 days with 2 complete responses and 1 partial response. There were no significant differences between 8 TN cases and the other cases from points of immunological and clinical responses. Lymphocyte frequency (Hazard ratio of 0.906, p=0.019) well associated with OS by multivariate Cox proportional hazard regression analysis for pre-vaccination samples. Conclusions: Next steps of PPV for the refractory breast cancer patients were warranted because of the lower toxicity and favorite immune responses along with possible clinical benefits.
Personalized peptide vaccine-induced immune response associated with long-term survival of a metastatic cholangiocarcinoma patient