Vaccine immunotherapy for prostate cancer: from mice to men.

Preclinical studies demonstrated the ability of an adenovirus/PSA (Ad/PSA) vaccine to induce strong anti-PSA immune responses, and these responses were capable of destroying prostate-specific antigen (PSA)-secreting mouse prostate tumors. A series of preclinical studies have demonstrated the superiority of the Ad/PSA vaccine to other PSA vaccines for the induction of anti-PSA immune responses, the ability of Ad/PSA vaccination combined with cytokine gene therapy and the TLR9 agonist CpG to enhance the anti-prostate tumor immunotherapy, and the reduction of negative regulatory elements when the vaccine was combined with 5-fluoruracil administration. A phase I clinical trial of the Ad/PSA vaccine in men with metastatic castrate-resistant prostate cancer demonstrated the safety of the vaccine even at the highest single dose permitted by the FDA.