Comparison of the efficacy of intravesical, bacillus Calmette-Guerin with thiotepa, mitomycin C, poly I:C/poly-L-lysine and cis platinum in murine bladder cancer

The efficacy of intravesical bacillus Calmette-Guerin for the treatment of the mouse bladder tumor MBT-2 was compared with that of thiotepa, mitomycin C, cis-diamminedichloroplatinum II and poly I:C/poly-L-lysine. MBT-2 cells were instilled into the bladder immediately after electrocauterization. Drug installations were initiated 24 hours later and continued on a weekly basis for 4 weeks. Both Calmette-Guerin and cis-diamminedichloroplatinum II significantly (p < .0004) inhibited MBT-2 tumor implantation when compared to diluent-treated controls. Neither mitomycin C, thiotepa nor poly I:C/poly-L-lysine significantly inhibited tumor implantation. Mean tumor weights also were significantly (p < .05) reduced in bacillus Calmette-Guerin cis-diamminedichloroplatinum II-treated mice, while tumor mean weights in mice treated with thiotepa, mitomycin C or poly I:C/poly-L-lysine were not significantly different than controls. These results suggest that the efficacy of intravesical bacillus Calmette-Guerin in comparison with other drugs in the MBT-2 mouse bladder tumor model is similar to observations reported in human clinical trials in which intravesical bacillus Calmette-Guerin was shown to be more effective than other cytotoxic drugs. These data further support the utility of the MBT-2 model for the study of the mechanisms by which bacillus Calmette-Guerin inhibits bladder tumor growth.