Dose–response efficacy and safety of PA21 in Japanese hemodialysis patients with hyperphosphatemia: a randomized, placebo-controlled, double-blind, Phase II study

BACKGROUND: Hyperphosphatemia is common in chronic kidney disease (CKD) and associated with mortality and morbidity. We aimed to evaluate the dose-dependent efficacy and safety of PA21 (sucroferric oxyhydroxide), an iron-based phosphate binder, in Japanese hemodialysis patients with hyperphosphatemia. METHODS: In this double-blind, multicenter, Phase II study, 183 patients were randomized to placebo or PA21 at doses of 250, 500, 750, or 1000 mg (based on iron content) three times/day for 6 weeks. The primary efficacy endpoint was the mean change in serum phosphorus levels from baseline to end of treatment in each group. Adverse reactions were evaluated. RESULTS: The change in serum phosphorus level was significantly greater in each PA21 group than in the placebo group (analysis of covariance: P < 0.001 for all groups). A dose-dependent change in serum phosphorus levels was observed in the PA21 groups. A notable decrease in mean serum phosphorus levels to the target level of ≤6 mg/dL was shown starting at Week 1 in all PA21 groups. The cumulative achievement rates for target serum phosphorus level at the end of treatment were generally >80 % in all PA21 groups. The major adverse reaction reported was diarrhea; however, most cases were mild. CONCLUSIONS: PA21 was an effective and safe treatment that decreased serum phosphorus levels starting at 1 week of treatment when administered as one 250-mg tablet three times/day. PA21 demonstrated a dose-dependent phosphorus lowering effect up to 3000 mg/day. PA21 may be a new treatment alternative with relatively low pill burden for Japanese hemodialysis patients with hyperphosphatemia.