Hyperphosphatemia is commonly observed among ESRD patients. It is described as an electrolyte disturbance in which there is an abnormally elevated level of phosphate in the blood. The nephrologist along with the dietitian controls and manages these levels. The phosphate binder plays a vital role in the well-being of a dialysis patient. The phosphate binders that clinicians are familiar with are Phoslo (calcium acetate), Tums (calcium carbonate) and Renvela (sevelamer carbonate).
In late December 2014, a new phosphate binder was introduced in the US by Keryx Pharmaceuticals under the trade name, Auryxia (ferric citrate).
What differentiates Auryxia from others binders? It is an iron based phosphate binder. Referencing its formulation, each tablet contains 210 mg of ferric iron, equivalent to 1 gram of ferric citrate. It is indicated to control serum phosphorus levels in patients with chronic kidney disease receiving dialysis treatment. It is absorbed in the GI tract, binds with the dietary phosphorus and is excreted, causing a decrease in serum phosphorus levels. During the clinical trials and examinations of iron parameters, Auryxia showed improvement in patient transferrin saturation and ferritin, believed to be associated with the systemic absorption of iron. This allows the reduction of IV iron administration and possibly ESA’s that could result in meaningful treatment cost savings.
Its pivotal trial for use on CKD patients is on-going, possibly expanding its label in the treatment of iron deficiency anemia. Its pivotal data is expected to be released soon. If results trend favorably and FDA approval is obtained for treating iron deficiency anemia and hyperphosphatemia to CKD patients, Auryxia might place itself ahead of the other phosphate binders.
As with other medication, review of the drug safety information is extremely important.