Therapeutic effect of a retinoid (Ro 10-9359) on rats with bladder tumours induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine upon administration alone or in combination with mitomycin C.

The therapeutic effect of an aromatic retinoic acid analogue (Ro 10-9359) and mitomycin C (MMC) on rats with bladder tumours induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) was examined. Eight-week-old female Wistar rats were given 0.05% BBN in drinking water for 8 weeks. Therapy was started at week 26 and all rats were killed at week 30. MMC at a dose of 0.3 mg/kg twice a week ip for 3 weeks significantly reduced the incidence and the mean number of tumours. With oral Ro 10-9359 at a dose of 100 mg/kg once weekly for 4 weeks, no significant effect was observed. The combination of MMC and Ro 10-9359 significantly reduced the mean number, but not the incidence, of tumours. The difference between the effect of MMC alone and that of MMC given in combination with Ro 10-9359 was not statistically significant. Thus no favorable effect of the retinoid could be demonstrated either alone or in combination with MMC.