Efficacy and safety of SBR759, a new iron-based phosphate binder

Treatment of elevated serum phosphorus in hemodialysis patients remains challenging due in part to the lack of a well-tolerated, safe, and effective phosphate binder. Here we report the results of a single-center, open-label, phase I clinical trial of 44 hemodialysis patients to show the safety and efficacy of a novel iron-based phosphate binder, SBR759. After establishing its safety at an initial dose of 3.75 g/day, SBR759 was given to successive cohorts in several divided doses of up to 22.5 g/day. The defined measure of efficacy was the average change in serum phosphorus in the cohorts receiving 11.25 and 15.0 g/day, in whom the mean reduction was 2.1 mg/dl. A clinically and statistically significant reduction in serum phosphorus was found across the entire dose range. All patients were able to achieve mean phosphorus levels within K/DOQI target ranges at the end of the first week. SBR759 was well tolerated within the anticipated clinical dose range of 3.75-15 g/day. No treatment-related serious adverse events were observed nor were there clinically relevant changes in iron indices. While these preliminary studies highlight the clinical efficiency and safety of SBR759, its promise of improved therapeutic options for hyperphosphatemia in patients with chronic kidney disease requires further study. Kidney International (2010) 77, 897-903; doi:10.1038/ki.2010.23;published online 10 March 2010