Assessment of the preclinical activity of budotitane in three different transplantable tumor systems, its lack of mutagenicity, and first results of clinical phase I studies.

The antitumor activity of budotitane was investigated in three different tumor systems--the transplantable murine ascitic-colon-adenocarcinoma MAC 15A, the TD-osteosarcoma of the rat, and the intramuscularly transplanted murine sarcoma 180. Marked inhibition of tumor growth was observed in the intramuscularly transplanted sarcoma 180, and cure rates of 50-80% were achieved in the colon adenocarcinoma MAC 15A. In contrast to these findings, bulotitane was inactive in the transplantable TD-osteosarcoma of the rat. Preliminary mutagenicity studies with the Salmonella typhimurium/mammalian microsome assay of Ames did not show any evidence of mutagenicity for the compound. The first results of the phase I clinical trials showed mild hepatotoxicity at a dose level of 15 mg/kg, dose-limiting nephrotoxicity at 21 mg/kg, and a reversible impairment of the sense of taste, beginning at a dose of 9 mg/kg.