Iron-based phosphate binders--a new element in management of hyperphosphatemia

Management of serum phosphorus in patients with chronic kidney disease remains a significant clinical challenge. A pivotal component of the clinical approach to maintaining serum phosphorus concentrations towards the normal range is the use of phosphate binding agents in addition to comprehensive dietary counseling. The available agents work similarly by capitalizing on a cation within the agent to bind negatively charged phosphorus, forming an insoluble complex and reducing ingested phosphorus absorption. Despite several effective options for phosphate binder therapies, patient adherence remains an issue, mainly due to adverse effect profiles and large daily pill burdens.

Two new iron-based phosphate binder therapies have recently become available in the United States, sucroferric oxyhydroxide and ferric citrate. These agents have both been shown to effectively reduce serum phosphorus comparably to widely used calcium-based binders and sevelamer salts.

The two new iron-based binders differ substantially with regard to phosphate binding chemistry and iron absorption profiles. Their place in therapy is still evolving and the impact of pill burden, gastrointestinal adverse effect profiles, potential cost reduction of anemia therapies and physiologic effects of long-term iron exposure need to be further evaluated.