A long-term, open-label extension study on the safety of treatment with lanthanum carbonate, a new phosphate binder, in patients receiving hemodialysis

Background: Lanthanum carbonate, a new phosphate binder, is effective in reducing serum phosphorus levels in patients with end-stage renal disease. A 1-year extension study to two randomized controlled studies was conducted to evaluate the long-term safety of lanthanum carbonate in patients who received hemodialysis. Research design and methods: Patients from two previous lanthanum carbonate studies were eligible to continue treatment in a 1-year openlabel extension. A total of 77 patients (N = 77; 11 from Study 1, 66 from Study 2) were enrolled in this extension. The mean age of patients was 60.9 years (SD +/- 12.5 years); 65% were male and 35% were female. All patients received lanthanum carbonate at the optimal dose for phosphorus control, determined in their previous study. Safety and tolerability were assessed by monitoring adverse events, laboratory parameters, and vital signs. The number of patients who maintained serum phosphorus levels at <= 5.9 mg/ dL (1.9mmol/L) was recorded, along with serum calcium, calcium x phosphorus product, and parathyroid hormone levels. Results: Lanthanum carbonate was well tolerated and was associated with few treatment-related adverse events. The most commonly reported adverse events were nausea (26.0%), peripheral edema (23.4%), and myalgia (20.8%). No treatment-related serious adverse events occurred. By Week 4, the mean serum phosphorus level had decreased by approximately 1 mg/dL to 5.7 +/- 2.0 mg/dL (1.84 +/- 0.7 mmol/L). At the end of the study, the mean pre-dialysis serum phosphorus level was 5.7 +/- 1.4 mg/dL (1.84 +/- 0.5 mmol/L); 53% of patients had controlled phosphorus levels. Calcium x phosphorus product decreased during Week 1 and remained within a clinically acceptable range thereafter There were no clinically significant changes in serum calcium, or parathyroid hormone levels. Conclusion: Lanthanum carbonate is well tolerated and is effective for the long-term maintenance of serum phosphorus control in patients with end-stage renal disease.