Superior efficacy of trimelamol to hexamethylmelamine in human ovarian cancer xenografts

A series of eight human ovarian cancer lines grown in nude mice were used to compare the activity of hexamethylmelamine (HMM) and N², N⁴, N⁶-trihydroxy methyl-N², N⁴, N⁶-trimethylmelamine (trimelamol). The tumor lines differed in histological subtype and growth rate. The drugs were administered i.p. at the maximum tolerated dose at alternate days. Differences in volume of treated and control tumors were endpoints of the study. The tumor lines varied widely in sensitivity to HMM and in four lines a T/C% below 25% was achieved. Trimelamol appeared to be more active than HMM and achieved a T/C below 25% in seven tumor lines. Thus far, the drug has demonstrated significant activity in a phase I trial in ovarian cancer patients. Comparative clinical studies of HMM vs trimelamol have not yet been performed.