Phase I evaluation of IMPY in a twice weekly schedule.

IMPY was given to 25 patients with advanced cancer on a twice weekly schedule in escalating doses from 165 to 3000 mg/m2. Nausea, vomiting, fatigue, generalized weakness, and decreases in performance status were dose-limiting. In one patient treated at a dose of 3000 mg/m2 for three doses, hemolytic anemia resulted, with a 6-g/dl decrease in hemoglobin. No tumor regression occurred. A reasonable starting dose for phase II studies is 1200 mg/m2 twice weekly for 3 weeks, with planned rapid escalation to 1800 mg/m2 in patients tolerating the lower dose level.