Follow-up evaluation of a phase II prostate cancer vaccine trial.
BACKGROUND
A phase II trial, involving infusions of autologous dendritic cells (DC) and two human histocompatibility antigen (HLA-A2)-specific prostate-specific membrane antigen (PSMA) peptides, was recently completed. Thirty percent of the participants, including subjects with hormone-refractory metastastic disease, and those with suspected local recurrence of prostate cancer, were identified as clinical responders. This report describes the follow-up evaluation of 19 responders in the two study groups.


METHODS
After conclusion of the study, study participants were subjected to follow-up evaluations at 6-8-week intervals. Each responder was reevaluated for response status, and duration of response was determined.


RESULTS
Subjects were observed for an average of 291 days (metastastic group, group A-2) and 557 days (local recurrence group, group B), which included the treatment and follow-up periods. The average duration of response was 149 days for group A-2, and 187 days for group B. A majority of responders (11/19; 58%) were still responsive at the end of the current follow-up.


CONCLUSIONS
The responses observed may be significant and relatively durable. This study suggests that DC-based cancer vaccines in the future may provide an additional therapy for advanced prostate cancer.
Tjoa
B A
BA
Pacific Northwest Cancer Foundation, Cancer Research Division, Northwest Hospital, Seattle, Washington 98125, USA.
Simmons
S J
SJ
Elgamal
A
A
Rogers
M
M
Ragde
H
H
Kenny
G M
GM
Troychak
M J
MJ
Boynton
A L
AL
Murphy
G P
GP
D000954:Antigens, Surface; D019496:Cancer Vaccines / Q000627:therapeutic use*; D002268:Carboxypeptidases / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D043425:Glutamate Carboxypeptidase II; D015789:HLA-A2 Antigen / Q000276:immunology; D006801:Humans; D007167:Immunotherapy; D016219:Immunotherapy, Adoptive; D007937:Leukapheresis; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000276:immunology / Q000628:therapy*
D000954:Antigens, Surface; D019496:Cancer Vaccines; D015789:HLA-A2 Antigen; D002268:Carboxypeptidases; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II; D017430:Prostate-Specific Antigen