Optimal phosphate control: still an unmet need in chronic kidney disease patients

Reduction of phosphate levels has traditionally been considered a mainstay treatment for patients with chronic kidney disease (CKD). Unfortunately, the treatment of hyperphosphatemia is far from being satisfactory. Available phosphate binders have limited efficacy, forcing the consumption of many tablets in order to achieve mild-to-moderate effect or low tolerability. Moreover, even if calcium-free phosphate binders, such as sevelamer and lanthanum carbonate, decrease serum phosphate levels without affecting serum calcium concentration, they do not significantly reduce circulating parathyroid hormone (PTH). The higher phosphate-binding efficacy of lanthanum carbonate should be balanced with the accumulation in bones and the lack of pleiotropic effects on lipid metabolism and inflammation. However, the fact that lanthanum carbonate seems to decrease the rate of development of vascular calcifications more or less similar to sevelamer suggests that phosphate control could actually be the key factor to improve patient outcome. New iron-based phosphate binders are undergoing clinical development. In addition to phosphate binding, they can be useful to treat anemia, and are undergoing Phase II clinical development for this indication. This could be of clinical importance particularly in CKD patients not on dialysis, avoiding the need for extra oral iron administration, and favoring compliance. In conclusion, the control of phosphate retention should still be considered an unmet medical need for CKD patients.