Bacteriolytic therapy of experimental pancreatic carcinoma

Figure 1 Data of in vivo-analyses of s. c. Panc02 tumors treated with Clostridium novyi-NT spores. A: Growth kinetics of s.c. Panc02 tumors; B: Survival curve of tumor-carrying mice after i.v. injection of Clostridium novyi-NT spores. For evaluation of the optimal therapeutic dose, different groups of tumor carrying mice were employed. These included tumor sizes below 150 mm³ (n = 10), of about 250 mm³ (n = 21) and larger than 450 mm³ (n = 6). Experiments identified a tumor-size dependent toxicity and response rate. Small tumors were completely unaffected and remained comparable to controls. In contrast, larger tumors responded with substantial necrosis followed by shrinkage and subsequent complete regression; C: Growth kinetics of tumors after rechallenge. Successfully treated animals (n = 5) received a second tumorigenic dose of Panc02 cells at day 28 post therapy. Naïve animals were used as controls. As can be depicted from the graph, bacteriolytic therapy mediated partial protection from re-exposure to tumor cells. Values are given as the mean tumor volume (mm³) ± SE; ^aP < 0.05 vs tumor control; ^bP < 0.001 vs tumor control; Mann-Whitney U-test.