Antitumor activity was evaluated in immunodeficient mice bearing subcutaneous Hs766T human pancreatic xenograft tumors. All treatments were administered by intravenous injections. Day 0 represents the day of treatment initiation. The paclitaxel dose was 20 mg/kg, given on day 0 and 4 for a total of 2 doses. A single PCat-siSurvivin dose (1 nmole) was given on day 3. Animals were maintained for up to 38 days after treatment initiation, with tumor size measurements taken every 3 or 4 days. Control animals received the same vehicle used in the treated groups, i.e., 50:50 Cremophor:ethanol diluted in physiological saline for when paclitaxel was given and PCat for when PCat-siRNA was given. Control (filled diamonds, n=3), PCat-siNT (filled squares, n=3), PCat-siSurvivin (PCat-siSur; filled triangles, n=3), paclitaxel+blank PCat (Pac; open diamonds, n=9), paclitaxel+PCat-siNT (Pac+PCat-siNT; open squares, n=5), paclitaxel+PCat-siSurvivin (Pac+PCat-siSur; open triangles, n=9). *p<0.05 vs. control, single agent PCat-siNT or single agent PCat-siSurvivin groups. **p<0.05 vs. all other groups. (A) Tumor-bearing animals after treatments. Note the small tumors in the paclitaxel+siSurvivin animals (indicated by red arrow). (B) Tumor growth. Mean+SD. (C) Kaplan-Meier plot of overall survival.