Control of serum phosphate by oral lanthanum carbonate in patients undergoing haemodialysis and continuous ambulatory peritoneal dialysis in a short-term, placebo-controlled study.

BACKGROUND: Hyperphosphataemia in dialysis patients is associated with significant morbidity. We assessed the ability of lanthanum carbonate to control phosphate levels in patients undergoing haemodialysis or continuous ambulatory peritoneal dialysis (CAPD) in a short-term, placebo-controlled study.

METHODS: This was a double-blind, placebo-controlled, parallel-group study consisting of three phases: a 2 week washout period; a 4 week, open-label, dose-titration phase; and a 4 week, double-blind, placebo-controlled phase. After washout, patients (n = 59) received lanthanum (375 mg/day), titrated up to a maintenance dose (maximum: 2250 mg) that achieved control of serum phosphate levels between 1.3 and 1.8 mmol/l (4.03-5.58 mg/dl). After titration, patients were randomized to receive their maintenance dose of lanthanum (n = 17) or placebo (n = 19) for 4 weeks. Control of serum phosphate was the primary efficacy assessment. Levels of calcium, parathyroid hormone, calcium x phosphate product and lanthanum as well as adverse events were evaluated.

RESULTS: By the end of titration, 70% of patients had serum phosphate levels < or =1.8 mmol/l. Lanthanum carbonate continued to control serum phosphate levels in the double-blind phase. At the end of the study, 64.7% of lanthanum carbonate-treated patients were controlled compared with 21.4% in the placebo group. Results in patients receiving CAPD were similar to those seen in the group as a whole. Mean parathyroid hormone levels (P = 0.41) and calcium x phosphate product (P<0.001) were both higher in the placebo than the lanthanum carbonate group.

CONCLUSIONS: Lanthanum carbonate is an effective phosphate binder able to control serum phosphate and calcium x phosphate product.