Phase I study of pentamethylmelamine.

Pentamethylmelamine is a soluble monodemethylated derivative of hexamethylmelamine. Its activity in animal tumors is similar to that of hexamethylmelamine. When given iv at a dose of 1200 mg/m2 to patients with advanced cancer, it produced severe nausea and vomiting, severe psychotropic effects, and EEG changes. When this dose was given for 10 consecutive days, there was marked but reversible myelosuppression. The severe CNS effects which occurred at doses sufficient to produce myelosuppression cast doubt on the potential utility of pentamethylmelamine.