 Based on our experience with HSV-tk and GCV in-situ gene therapy, it appears that maximal immune stimulation occurs about 2 weeks following vector injection. Furthermore, repeat injections of an adenoviral vector do not result in excess toxicity or in the generation of anti-adenoviral antibodies sufficient to suppress vector activity. We propose here an intraprostatic injection of RTVP-1 in an adenoviral vector 4-6 weeks prior to radical prostatectomy, in order to allow full expression of the gene therapy tissue effects. 