SAN DIEGO—Ferric citrate is at least as potent as other phosphate binders and it raises serum sodium bicarbonate levels, according to a pilot study of hemodialysis (HD) patients requiring high doses of phosphate binders. Ferric citrate offers the promise of a lower pill burden for patients, researchers said.
In a phase 2 non-blinded trial, he and his colleagues studied 55 HD patients who, at baseline, were taking six to 30 tablets or capsules of their phosphate binders daily. The patients were switched, without a washout period, to ferric citrate at a starting dose of either 3.4 or 6 g/day based on the number of tablets or capsules the patients were taking at baseline. The patients took the ferric citrate for four weeks. The drug was titrated based on weekly blood draws to achieve serum phosphorus levels ranging from 3.5 to 5.5 mg/dL.
Ferric citrate maintained baseline serum levels of phosphorus, calcium, and intact parathyroid hormone (iPTH) and raised sodium bicarbonate levels, according to the researchers. The mean phosphate and calcium levels were 5.9 mg/dL and 9.2 mg/dL, respectively, at baseline, and 5.4 and 9.1 mg/dL at the end of the study. The mean iPTH was 530 pg/mL at baseline and 500 pg/mL at the end of the study. Mean sodium bicarbonate levels rose significantly from 22.2 mEq/L at baseline to 23.7 mEq/L at the end of the study, the investigators reported.
Based on the dosages of ferric citrate used in the study and the current formulation of ferric citrate (1 gram per capsule), equivalent phosphate control may be achieved with fewer pills, said investigator Marvin Sinsakul, MD, Assistant Professor of Medicine at Rush University Medical Center in Chicago, who reported study findings here at the American Society of Nephrology’s Renal Week conference.
Of the 55 patients, 25 received IV iron during the four-week study period. In this group, serum ferritin increased by 15% between baseline and the end of the study. Baseline and end of study serum levels of ferritin and iron were similar in the 30 patients who did not receive IV iron.
The treatment was well tolerated, the investigators reported. The most common adverse event associated with treatment was darkening of feces.