In vitro activity of menogaril and N-demethylmenogaril in a human tumor cloning assay.

The activity of menogaril and its major metabolite in animals and humans, N-demethylmenogaril, has been investigated in the human stem cell assay as developed by Salmon et al. Among 31 evaluable samples, four were sensitive to menogaril, including one which responded to N-demethylmenogaril. Three samples resistant to menogaril responded to N-demethylmenogaril. None was sensitive to doxorubicin. Overall, one out of seven ovarian samples and one out of three breast samples responded to menogaril. Our data confirm the in vitro activity of menogaril in ovarian and breast cancer; in addition, they suggest incomplete cross-resistance between doxorubicin and menogaril and, considering the concentrations of N-demethylmenogaril in animals and humans, a minor role for this metabolite in the overall antitumor activity of the parent compound.