ATLANTA—New data show that the novel iron-based phosphate binder PA21 is safe and efficacious out to 52 weeks, researchers reported at the American Society of Nephrology’s Kidney Week 2013 meeting.

The data are from a phase 3 open-label study looking at the one-year efficacy of PA21 versus sevelamer carbonate. In the study, Stuart M. Sprague, DO, of NorthShore University Health System in Evanston, Ill., and colleagues randomized 1,059 dialysis patients to receive PA21 1-3 grams/day (710 patients) or sevelamer carbonate 2.4-14.4 grams/day (349 patients) for 12 weeks’ dose titration followed by 12 weeks maintenance. Ninety-nine dialysis patients receiving PA21 were re-randomized to evaluate PA21 maintenance-dose versus low-dose control (250 mg/day) from weeks 24-27 (primary endpoint).

Patients who completed treatment, excluding those on low-dose PA21, were enrolled in a 28-week extension study. Secondary endpoints included change in serum phosphorus from baseline to week 12 to assess non-inferiority of PA21 versus sevelamer carbonate; long-term safety and efficacy of PA21 and sevelamer carbonate.

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A total of 549 patients completed the extension study. PA21 and sevelamer carbonate efficacy were maintained, according to the investigators. The mean serum phosphorus decline from baseline—more than 2 mg/dL—was similar for both binders. The mean tablet number over 52 weeks was lower for PA21 than sevelamer carbonate (3.3 vs. 8.7).

In addition, serum ferritin and transferrin saturation increased with PA21 over the first 24 weeks and then stabilized, with no evidence of iron accumulation with PA21 over 52 weeks, Dr. Sprague’s group reported. Both medications were well tolerated, with no notable difference in safety between groups.