Interspersion of cyclophosphamide and BCG in the treatment of L1210 leukemia and Lewis Tumor.

The therapeutic value of interspersing cyclophosphamide (CPM) chemotherapy and BCG immunotherapy was investigated in two tumor models: L1210 leukemia and Lewis solid tumor (LLT). In the case of L1210 leukemia, the antileukemic effect of CPM was enhanced by subsequent BCG administration where a single cycle of combined treatment was applied; treatment by repeated doses of CPM interspersed with BCG was no more effective than CPM chemotherapy alone. In the case of LLT tumor, the effect of one cycle of combined CPM-BCG treatment was not different from CPM administered alone but treatment by repeated doses of CPM interspersed with BCG immunotherapy was less effective than CPM chemotherapy alone. These results indicate that, while the effect of BCG immunotherapy may be favorable or nil when BCG is applied after cell-reducing chemotherapy, it may be nil or unfavorable when applied repeatedly in interspersed chemoimmunotherapy treatments.