Ilmofosine, an ether lipid derivative of lysophosphatidylcholine has antineoplastic activity in vitro and in vivo. Maximum efficacy in preclinical models is associated with prolonged exposure to the drug. In a Phase I trial of a weekly 2 hour infusion schedule of ilmofosine, a syndrome of lethargy, diminished performance status, and mild hepatotoxicity was dose-limiting at 550 mg/m2. To avoid the higher drug concentrations associated with a brief infusion, a Phase I study of a weekly 24 hour infusional schedule was undertaken in an attempt to maximize dose-intensity. Doses were escalated from 550 to 800 mg/m2. Toxicities included nausea, anorexia, fatigue, and minor elevations of liver function tests. The dose limiting toxicity at 800 mg/m2 was a syndrome of severe abdominal pain. No neutropenia or thrombocytopenia was observed except in one patient who was found to have a myelodysplastic syndrome, thought not to be related to drug therapy. The more prolonged infusion schedule of ilmofosine did not result in a substantial increase in the tolerable dose.
