A phase I study on a weekly schedule of DWA 2114R, a new platinum analogue, was conducted in 21 patients with various tumor types by clinical groups at 10 institutions. Nineteen of the 21 patients entered in this study were evaluable. The starting dose was 200 mg/m2 (1 n) administered intravenously for 1 hr and gradually escalated stepwise to 700 mg/m2 (3.5 n). The dose limiting factor (DLF) was leukocytopenia, especially neutropenia and maximum tolerated dose (MTD) was 700 mg/m2. The major clinical toxicity was gastrointestinal. Nephrotoxicity and hepatotoxicity were mild. Ototoxicity and cardiac failure did not emerge. Following administration of the drug, total platinum (Pt) showed a biphasic decay and AUC of total Pt was dependent on the dose. Excretion into urine 24 hr was between 42.6 and 100% of the administered platinum. The recommended dose of phase II study on a weekly schedule was 600 mg/m2, repeated every 2 or 3 weeks and administered via intravenous within drip infusion.