Lanthanum carbonate versus standard therapy for the treatment of hyperphosphatemia: safety and efficacy in chronic maintenance hemodialysis patients.

AIMS: No conventional phosphate binder is entirely satisfactory for the treatment of hyperphosphatemia in patients with end-stage renal disease (ESRD). Consequently, there is a need for new agents. One such agent is lanthanum carbonate (La). This large-scale study compares the safety of La with standard therapy (any approved phosphate binder) in patients who were treated for up to 2 years. Efficacy, having previously been demonstrated, was a secondary endpoint.

MATERIALS AND METHODS: After washout, patients were randomized to receive La (n=682) or their pre-study phosphate binder (n=677). Over a 6-week period, La was titrated to a maximum daily dose of 3000 mg elemental lanthanum (serum phosphorus target levels for titration were < or = 5.9 mg/dl (1.90 mmol/l)). Safety assessments included adverse events (AEs), full laboratory parameters and blood profiles. Efficacy assessments included serum phosphorus, calcium, calcium x phosphorus product and parathyroid hormone (PTH) levels.

RESULTS: Average treatment exposure was greater in the standard therapy group (501.4 days) than in the La group (370.3 days) because standard therapy patients who switched or combined treatments were allowed to continue in the study. The most common AEs were gastrointestinal. The incidences of AEs in the La and treatment exposure-corrected standard therapy groups were nausea, 37 versus 29%; vomiting, 27 versus 22% and diarrhea (24% in each group). Hypercalcemia that was reported as an AE (La versus treatment exposure-corrected standard therapy) occurred in 4.3% and 8.4% of patients, respectively. There was no indication of liver toxicity, suppression of erythropoiesis or changes in the mini-mental state examination. Over 2 years, phosphorus control was similar in both groups; in the La group, however, serum calcium was lower and serum PTH levels were maintained in the range recommended by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI).

CONCLUSIONS: The 2-year tolerability and efficacy of La are similar to those seen with standard therapy, although lower serum calcium levels and improved PTH levels were observed in the La group. These results support La as a viable new option for the management of hyperphosphatemia in ESRD.