Keryx Biopharmaceuticals, Inc. is a biopharmaceutical company. The Company is focused on the development of products for the treatment of renal diseases. The Company's product Auryxia (ferric citrate), also known as Riona in Japan and Fexeric in Europe, is an oral, absorbable iron-based compound, which is indicated for the control of serum phosphorus levels in patients with chronic kidney disease (CKD), on dialysis. The Company operates through the products segment. Auryxia can bind to phosphate in the gastrointestinal tract and form non-absorbable complexes to reduce intestinal absorption and aid in the management of hyperphosphatemia in patients with CKD. The adverse events for Auryxia treated patients were gastrointestinal-related, including diarrhea, nausea, constipation, vomiting and cough. The Company focuses on Keryx Patient Plus program to assist with patient accessibility to Auryxia.