Lanthanum carbonate: a postmarketing observational study of efficacy and safety

Background: Hyperphosphatemia is associated with morbidity and mortality in hemodialysis patients. The use of calcium chelators is restricted by the risk of hypercalcemia and vascular calcifications. Sevelamer, a non-calcium chelator, is associated with risks of metabolic acidosis and poor compliance. Lanthanum carbonate is a non-calcium chelator not associated with these issues. However, accumulation in liver and bone has been a reason for concern. Methods: Adult patients (n=112) from 9 hemodialysis centers, with serum phosphorus >5.5 mg/dL and on hemodialysis for >1 year, were selected to switch to lanthanum carbonate (mean dosage: 2,189 +/- 491 mg/day); 103 completed the study. Laboratory assays for serum phosphate, calcium, parathyroid hormone, alkaline phosphatase, gamma-glutamyl transpeptidase (gamma GT), aspartate transaminase, alanine transaminase and plasma bicarbonate were performed monthly. Seven patients underwent a bone biopsy for evaluation of lanthanum bone content. Results: Switching to lanthanum carbonate led to a reduction in mean serum phosphate levels (-18.2%; p<0.001) and calcium x phosphorus product (-17.6%; p<0.0001). There were no important changes in other variables, except for an increase in transaminases in 2 patients with preexisting liver disease, who discontinued therapy. An increase in plasma bicarbonate concentration was observed (p=0.001). Although some lanthanum was detected in bone, its distribution did not follow the mineralization front. Conclusions: Lanthanum carbonate is effective and well tolerated, provided that recipients do not have preexisting liver disease. After 8 months of treatment, lanthanum was not detected in the mineralization front of bone. In hemodialysis patients, lanthanum carbonate does not seem to be involved in metabolic bone disease.