The most widely used drug for iron chelation is deferoxamine (DFO) mesylate. While effective in promoting iron excretion, it requires prolonged daily infusions, often resulting in poor compliance. A clinical trial was conducted using starch-conjugated DFO (S-DFO; 40SD02), a high-molecular-weight iron chelator possessing prolonged vascular retention. Single doses of S-DFO were infused intravenously into groups of four transfusion-dependent patients with beta-thalassaemia at doses of 150, 300, 600 and 900 mg/kg. Urinary iron excretion and various pharmacologic parameters were evaluated for 1 week and safety for 3 weeks. No drug-related effects were observed on clinical chemistries, haematological and coagulation parameters, urinalyses, vital signs or electrocardiograms. Drug-related adverse events were limited to four urticarial reactions, none requiring termination of the infusion. The drug stimulated clinically significant urinary iron excretion, with the highest dose (900 mg/kg) inducing excretion of 1.31 mg of iron/kg (range 0.79-1.90 mg/kg) over 1 week, with residual iron-binding capacity present in the plasma for over 6 d. In summary, treatment with S-DFO, administered weekly, has the potential to achieve iron balance in the poorly compliant patient.