Phase I evaluation of SOAz (1,3,3,5,5 pentakis(aziridino)-1 lambda 6, 2,4,6,3 lambda 5, 5 lambda 5...

Eleven patients with advanced cancer were treated with SOAz, the first aziridino substituted inorganic heterocyclic compound to undergo phase I clinical trials. The agent was administered as a rapid i.v. infusion once a week in a dose of 50, 75 or 100 mg/m2. Severe myelotoxicity, which was prolonged and delayed in onset, precluded continuing treatment for more than three courses in 9 of 11 patients. In two patients thrombocytopenia showed no signs of recovery 9 and 11 weeks after the last infusion. Two minor responses were noted and there was one therapy-related death. Because of severe myelotoxicity, which is cumulative and may be irreversible, this treatment schedule seems unsuitable for phase II studies.