Schedule and timing of Ad5‐PNP and F‐ara‐AMP were determined from previous data showing: (1) transgene expression following Ad5‐PNP is maintained in solid tumors after 4–5 days, and (2) fludarabine phosphate at 167 mg/kg is safe and effective in other tumor settings3 (and unpublished observations). This evidence concerns the gene PNP and neoplasm.