Intravesical immunotoxin as adjuvant therapy to prevent the recurrence of bladder cancer

To assess the intravesical application of immunotoxin as adjuvant therapy to prevent recurrence after tumor resection in bladder cancer patients.

An anti-human immunotoxin against bladder carcinoma, BDI-1-RT, was prepared and its in vitro targeting cytotoxicity estimated. The immunoreactivity of BDI-1-RT with human bladder cancer tissue of different grades and stages was detected by immunohistochemical analysis. After safety test, intravesical administration of BDI-1-RT was performed in 31 patients while mitomycin C (MMC) was used in 36 patients serving as a control group. The recurrence rates and side effects in both groups were recorded. In addition, the development of human anti-mouse antibodies (HAMA) was determined by ELISA, to assess the potential safety of this immunotoxin.

In our study, BDI-1-RT had immunoreactivity with 81.6% of bladder transitional cell carcinomas. The immunoreactivity of BDI-1-RT correlated with tumor grade. High-grade carcinoma had stronger staining than low-grade (P < 0.05). There was no significant difference between the BDI-1-RT group (10%) and MMC group (19.3%) in recurrence rate (P > 0.05). Side effects, including systemic and local, were more frequent in the MMC group (11 of 36 patients versus 2 of 31, P < 0.05). HAMA was not detected in any of 7 patients.

Immunotoxin may have considerable potential in the prophylaxis of bladder transition cell carcinoma.