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Phase 3 study demonstrates ferric citrate effectively treats iron deficiency anemia
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Keryx Biopharmaceuticals recently reported positive results of a pivotal phase 3 study that showed ferric citrate effectively increased the hemoglobin level in patients with iron deficiency anemia from stage III to V non-dialysis–dependent chronic kidney disease.
The FDA previously approved ferric citrate (Auryxia, Keryx Biopharmaceuticals) — an oral iron-based medicine — for the control of serum phosphorous levels in patients with chronic kidney disease (CKD) on dialysis.
If approved, ferric citrate would be the only FDA–approved iron treatment in tablet form available to patients with stage III to V non-dialysis–dependent CKD.
The phase 3 study included 234 patients who had not adequately responded to or tolerated oral iron therapies who were randomly assigned 1:1 to receive ferric citrate or placebo.
The study consisted of a 16-week, randomized, double blind, placebo-controlled, efficacy period followed by an 8-week open-label safety extension period in which all patients remaining in the study, including the placebo group, received ferric citrate.
Patients who received ferric citrate received a starting dose of three tablets per day and could receive an additional three tablets per day every 4 weeks for a maximum of 12 tablets per day. Overall, patients received a mean dose of five tablets per day.
The proportion of patients who achieved a 1 g/dL or greater increase in hemoglobin at any point during the 16-week efficacy period served as the primary endpoint. Secondary endpoints consisted of mean change in hemoglobin, transferrin saturation (TSAT), ferritin and serum phosphate, as well as the proportion of patients with a durable response during the efficacy period.
In total, 52.1% of patients who received ferric citrate achieved a 1 g/dL or greater increase in hemoglobin at any point in the 16-week period compared with 19.1% of patients in the placebo group (P < .001).
Patients who received ferric citrate also demonstrated an improved mean change in hemoglobin (.075 vs. –0.08 g/dL, P < .001), TSAT (17.8% vs. –0.6%, P < .001), ferritin (162.5 vs. –7.7 ng/mL, P < .001) and serum phosphate (–0.43 vs. –0.22 mg/dL, P = .02).
Further, 48.7% of patients in the treatment arm achieved a durable response during the efficacy period compared with 14.8% of patients in the placebo group.
“These phase 3 results demonstrate that ferric citrate can effectively raise hemoglobin levels in stage III to V non-dialysis–dependent CKD patients, with effects observed as early as 2 weeks post-treatment initiation,” John Neylan, MD, chief medical officer of Keryx Biopharmaceuticals, said in a press release.
Patients experienced mild to moderate adverse events, including diarrhea (ferric citrate, 20.5%; placebo, 16.4%), constipation (ferric citrate, 18.8%; placebo, 12.9%), discolored feces (ferric citrate, 14.5%; placebo, 0%) and nausea (ferric citrate, 11.1%; placebo 2.6%) during the efficacy period.
Overall, 12% of patients treated with ferric citrate and 10% of patients in the placebo arm reported serious adverse events; however, no serious adverse events were deemed drug related.
During the efficacy period, 26% of ferric citrate-treated patients and 30% of patients in the placebo group discontinued treatment. Twelve patients in the treatment arm and 10 patients in the placebo group discontinued due to an adverse event.
Keryx Biopharmaceuticals plans to submit a supplemental new drug application to the FDA in the third quarter to expand the label for ferric citrate to include the treatment of iron deficiency anemia in people with stage III to V non-dialysis–dependent CKD.
“We believe that the ability to treat iron deficiency anemia, managing hemoglobin and iron levels, could have an important effect on the way kidney specialists treat these patients,” Neylan added.
Disclosure: Neylan reports employment with Keryx Biopharmaceuticals.