ICRF-187 is the (+) enantiomer of the racemic mixture razoxane (ICRF-159). This compound is much more water soluble and thus could be formulated for parental use. The maximum tolerated dose in children after phase I trials was determined to be 3500 mg/M2/day x 3 days. A phase II trial of ICRF-187 was done in 21 children with solid tumors and 35 children with acute leukemia. All these patients were less than 21 years of age, had recovered from previous chemotherapy, had normal liver and kidney functions, and had a life expectancy of greater than 4 weeks. ICRF-187 was administered at a dose of 3 g/M2/day for 3 days as a 4 hour infusion each day. In patients with leukemia, no objective response was seen in the bone marrow although a few patients had a decrease in peripheral blast count. There were no measurable responses seen in patients with a solid tumor. ICRF-187 was well tolerated. The major toxicity was hematopoietic depression. Significant but rare toxicities included moderate to severe nausea and vomiting, and elevation of bilirubin and transaminases. Although inactive in the current study, ICRF-187 might be more active in another schedule.