[Phase I study of bestrabucil (KM 2210)].

A phase I study was performed on a newly developed antitumor agent, Bestrabucil (KM 2210). The study was started at an initial dose of 1 n 25 mg/body, and gradually increased up to 32n 800 mg/body. With single (35 patients) and five-consecutive-day (36 patients) administration, the dose-limiting factor was found to be tarry stool, remarkable decrease in hemoglobin content, and strong nipple and breast pain. The maximum tolerated dose (MTD) was concluded to be around 700 to 800 mg/body. With long-term administration (the longest term, 20 weeks, 36 patients), the dose-limiting factor was concluded to be a decrease in the peripheral leukocyte count when the total amount administered reached about 10 g. Side effects on the alimentary system due to this agent, such as vomiting, nausea and anorexia, were observed. In addition, mastalgia and genital bleeding due to released estrogen were also seen, especially in the case of long-term administration.