Phase II prostate cancer vaccine trial: Report of a study involving 37 patients with disease recurrence following primary treatment

BACKGROUND. A phase IT trial was conducted to assess the efficacy of infusi ons of dendritic cells (DC) and two HLA-A2-specific prostate-specific membr ane antigen (PSMA) peptides (PSM-P1 and -P2). This report describes the eva luation of 37 subjects admitted with presumed local recurrence of prostate cancer after primary treatment failure. METHODS. All subjects received six infusions of DC pulsed with PSM-P1 and - P2 at 6-week intervals. Clinical monitoring was conducted pre-, during, and post-phase II study. Data included: complete blood count, bone and total a lkaline phosphatase, prostate markers, physical examination, performance st atus, bone scan, ProstaScint(R) scan, and chest X-ray, as well as other ass ays to monitor cellular and humoral immune responses. RESULTS. One complete and 10 partial responders were identified from this g roup based on National Prostate Cancer Project criteria, or on a 50% reduct ion of prostate-specific antigen (PSA), or on a significant resolution in l esions (biopsy-proven when possible) on ProstaScint(R) scan. CONCLUSIONS. About 30% of study participants in this group showed a positiv e response at the conclusion of the trial. This study suggests that DC-base d cancer vaccines may provide an alternative therapy for prostate cancer pa tients whose primary treatment failed. (C) 1999 Wiley-Liss, Inc.