The U.S. Food and Drug Administration has approved Keryx Biopharmaceuticals Inc.’s Auryxia to treat iron deficiency anemia in adults with chronic kidney disease, not on dialysis. The drug was originally approved in September 2014 for the control of serum phosphorus levels in people with chronic kidney disease who require dialysis.

Auryxia’s supplemental new drug application (sNDA) approval was based on results from a 24-week placebo controlled Phase 3 clinical trial in 234 adults with stage 3-5 non-dialysis dependent chronic kidney disease. Patients enrolled in the trial had hemoglobin levels between 9.0 g/dL and 11.5 g/dL and were intolerant to or had an inadequate response to prior treatment with oral iron supplements. The starting dose in the study was three tablets per day taken with meals; the mean dose was five tablets per day.

“More than half of the approximate 30 million people in the United States living with chronic kidney disease are iron deficient, and yet, this is the only tablet that has been developed and approved specifically to address iron deficiency anemia in these patients, who are not on dialysis,” said Steven Fishbane, MD, chief, division of kidney diseases and hypertension, department of medicine, Northwell Health in Great Neck, New York. “Starting today, physicians can prescribe an oral iron medicine to help people living with this condition, the majority of whom are not being optimally treated.”

During the study, patients were not allowed to receive any intravenous or oral iron, or erythropoiesis-stimulating agents (ESAs). In the study, treatment with Auryxia demonstrated significant increases in hemoglobin levels of >1 g/dL at any point during the 16-week efficacy period for the majority of patients (52.1%, n=61/117, compared to 19.1%, n=22/115, in the placebo group), a clinically meaningful result.

In the trial, ferric citrate was generally well tolerated and adverse events were consistent with its known safety profile. The most commonly reported adverse events in the Phase 3 study were diarrhea (21%), constipation (19%), discolored feces (15%), nausea (11%), abdominal pain (6%), and hyperkalemia (7%).