Improving phosphate-binder therapy as a way forward.

Abstract

Aluminium- or calcium-based phosphate-binding agents traditionally have been used to treat hyperphosphataemia in patients with end-stage renal disease. Although these agents effectively lower serum phosphorus levels, they are associated with serious side effects. Aluminium-based agents are associated with bone toxicity, renal osteodystrophy and encephalopathy, and calcium-based agents increase the risk of hypercalcaemia and cardiovascular calcification. Consequently, there remains a need for new, safe and effective non-calcium-, non-aluminium-based alternative treatments. Fortunately, several new agents are now available or are in the late stages of development, including sevelamer hydrochloride and lanthanum carbonate. Although sevelamer hydrochloride represents a step forward in the management of hyperphosphataemia, it has several drawbacks and is far from being the ideal phosphate binder. Lanthanum carbonate is the most recent non-calcium, non-aluminium phosphate binder to be developed for the treatment of hyperphosphataemia. Animal studies have shown it to be as effective as aluminium, without the associated toxicity. In clinical studies, lanthanum carbonate significantly reduced serum phosphorus levels, compared with placebo. It shows a similar efficacy to calcium carbonate in controlling serum phosphorus levels, but requires lower doses. In addition, lanthanum carbonate is at least as well tolerated as calcium carbonate, but is not associated with hypercalcaemia. Importantly, it has a positive effect on bone histology, with no evolution towards low bone turnover. Lanthanum carbonate, therefore, moves closer to the ideal phosphate binder.