Phase I study with an autologous tumor cell vaccine for locally advanced or metastatic prostate cancer

Abstract

Purpose: To attempt the isolation and primary culture of prostate tumor cells, to use the cultured cells for active immunotherapy, and to evaluate the safety and efficacy in a Phase I clinical trial.

Materials and methods: Tumor fragments were collected from 50 patients with prostate-specific antigen (PSA) > or = 10 ng/mL, < or = cT2 PCa who underwent radical retropubic prostatectomy (RRP) and 6 patients with metastatic PCa who underwent transurethral resection of the prostate (TURP). Cultured tumor cells were incubated with IFN-fi, irradiated, and cryopreserved. Seven vaccine inoculations were performed into > or = pT3 and/or N+ patients, and M+ patients, with the first two doses admixed with Bacille Calmette-Guerin (BCG). Follow-up was performed with measurement of delayed-type hypersensitivity (DTH) reactions, PSA and hemato-chemical tests, and bone scans.

Results: No cell culture was obtained in the TURP group. Cell culture and vaccine production were obtained in 37 cases (74%) in the RRP group. Eleven > or = pT3 and/or N+ patients were vaccinated. Toxicity was generally limited to the inoculation sites. DTH reactions > or = 10 mm were observed in 2 patients and > or = 5 mm in 6 patients. Two patients had a decrease in PSA levels after vaccine administration.

Conclusions: The autologous cell vaccine is safe and seems to induce a positive immune cellular response. Primary cell culture and vaccine production can be obtained for most RRP patients, but not for TURP patients using our method. There seems to be some influence of the vaccine in PSA evolution after RRP.