Bisantrene is a substituted anthracene derivative which preclinically demonstrated a spectrum of activity similar to that of doxorubicin but without associated cardiotoxicity. A Phase I evaluation of the drug has been performed using daily i.v. administrations for 5 days. Sixty courses of treatment were administered to 23 patients at doses from 2.5 to 90 mg/sq m/day. Courses were repeated at 4-week intervals. Dose-limiting toxicities were leukopenia and local cutaneous reactions. The leukopenia was dose related, noncumulative, and of brief duration. Local reactions occurred in 14 of 37 courses administered at doses greater than 60 mg/sq m and in 13 patients resulted in clinical cellulitis of the infused extremity. Gastrointestinal side effects were mild. No alopecia or cardiotoxicity was observed. Two mixed responses were obtained in patients with hypernephromas. Using a daily schedule for 5 days, approximately 40% more drug can be delivered per course than by single-day i.v. administration. However, with this schedule, local cutaneous reactions may prove additionally dose limiting. Phase II studies of Bisantrene in a daily i.v. schedule for 5 days are planned at a dose of 80 mg/sq m/day to be repeated every 4 weeks.