Hexamethylmelamine: a critical review of an active drug.

Hexamethylmelamine is an s-triazine that began clinical trials during the 1960s based on its level of antitumor activity in murine tumor models. Phase I studies were performed using an oral formulation given in divided doses for varying numbers of days. The most frequently reported toxicities included nausea, vomiting, abdominal cramps, anorexia, weight loss and malaise. Less frequently reported toxicities were anemia, thrombocytopenia, leucopenia and peripheral neuropathy. Clinical antitumor activity was noted in the phase I studies in a variety of tumor types. Since then a large number of studies have been performed using hexamethylmelamine as a single agent and in a variety of combinations. Unfortunately, almost none of these studies sought to define the utility of this drug relative to other treatments for the diseases in which it showed activity, or to define the contribution of this drug to the activity of any given combination. Thus its role in the treatment of patients with malignancies remains undefined.