Chemoimmunotherapy of murine bladder cancer.

The lethality of invasive transitional cell carcinoma (TCC) has prompted a search for effective, minimally toxic, adjuvant therapy. Such agents were evaluated in a murine bladder cancer (MBT2) model which parallels the clinical disease. One hundred C3H/He mice were inoculated i.d. with 2.5 x 10(4) viable MBT2 tumor cells and randomized to receive either normal saline (control), cis-Platinum (CPT), cyclophosphamide (CY), methotrexate (MTX), BCG, (CY + MTX), or (CY + MTX + BCG). Chemotherapy was given intraperitoneally weekly starting on day 7 after inoculation. Immunotherapy was given intralesionally on days 1 and 10 only. All mice were treated for 5 weeks followed by 5 weeks of observation. At 5 weeks, tumors of mice receiving cyclophosphamide alone or either of the combinations of therapy were smaller (P less than 0.01) than tumors of controls or other single agents alone. Each regimen increased survival, but only the combination regimen increase survival significantly (P less than 0.01). In the doses and schedule used in this model. Combination chemotherapy and chemoimmunotherapy significantly delay tumor growth and increase duration of survival (P less than 0.01) when compared with controls or single agent groups.