Novel Phosphate Binder Oxylanthanum Carbonate Effectively Reduced Serum & Urine Phosphorus Concentrations in Animal Models

Over 40% of dialysis patients have above-target phosphate. The efficacy and safety of oxylanthanum carbonate(OLC), a novel phosphate binder that forms the same insoluble phosphate complex as lanthanum carbonate, were assessed in 2 animal models. 3 groups of nephrectomized cats(n=4 per group) received 0.0466 g OLC/kg body weight, 0.2330 g OLC/kg body weight, or placebo. 6 groups of rats (n=6 per group) received placebo or 0.049, 0.099, 0.197, 0.394, or 0.788 g OLC/day. Endpoints included phosphate concentrations(urine, fecal, plasma) and serum lanthanum concentrations. All animals were observed for tolerance, injury, and mortality. In cats, urine phosphorus concentrations decreased across treatment groups and fecal phosphorus excretion increased in higher dose groups compared to control and lower dose groups. A clear but non-significant decline in plasma phosphate was observed. In rats, urinary phosphorus concentrations also decreased in all groups. The majority of serum lanthanum concentrations for rats in treatment groups were not significantly different from those in control groups. The study drug was well-tolerated in both models. OLC was effective for phosphate management and efficacy may be dose-dependent. OLC was safe and well-tolerated, indicating that it should be evaluated in the target population of patients with hyperphosphatemia.