Phosphorus load is associated with the risk of cardiovascular events and all-cause death in patients with chronic kidney disease (CKD), and thus regulation of serum phosphorus level is one of the most important treatment strategies for CKD–mineral and bone disorders.1-4 However, approximately 30% of Japanese patients requiring hemodialysis (HD) do not achieve the target range of serum phosphorus levels proposed by the Japanese Society for Dialysis Therapy, despite the use of phosphate binders.5 Tenapanor is a novel drug for the management of hyperphosphatemia that selectively inhibits sodium/hydrogen exchanger 3 (NHE3) on the luminal side of intestinal epithelial cells, thereby blocking the paracellular influx of phosphate.