[Phase I study of MST-16]

Phase I study with a new oral anticancer agents. MST-16 (Sobuzoxane), was conducted by 3 administration schedules: single, 5 consecutive days and 10-15 consecutive days. No toxicity was observed in the single administration at doses escalated up to 1,500 mg/m2. Dose-dependent leukopenia was observed from 560 mg/m2/day in consecutive 5 day administration, and median days to the nadir and recovery were about 2 and 1 week, respectively. GI-disorders were also observed sporadically from 800 mg/m2/day. One patient with Hodgkin's disease receiving 1,000 mg/m2/day achieved complete response. Consecutive administration for 10-15 days was carried out at a dose of 800 mg/m2/day. Six out of 7 evaluable patients demonstrated leukopenia, and all 2 patients treated for 15 days experienced leukopenia with a nadir corresponding to grade 3. Median days to nadir and recovery were both about 2 weeks. Doses recommended for phase II study were considered to be 1,600 mg/body/day for 5 days and 1,200 mg/body/day for 10-14 days.