Phase 3 study of Zerenex for the treatment of dialysis-associated hyperphosphatemia

Keryx announced results from its Phase 3 trial of Zerenex (ferric citrate) for the treatment of elevated serum phosphorus levels, or hyperphosphatemia, in patients with end-stage renal disease (ESRD) on dialysis. This study enrolled 151 dialysis patients. It was a multicenter, randomized, open-label trial with a two-week washout period, following which patients were randomized 1:1:1 to receive a fixed dose of Zerenex of either 1 gram, 6 grams or 8 grams per day for a treatment period of 28 days. The Intent-to-Treat (ITT) group included 146 patients, representing all patients who took at least one dose of Zerenex and provided a Baseline (at the end of washout) and at least one post-Baseline efficacy assessment.  Efficacy assessments were taken weekly starting at Baseline and subsequently at days 7, 14, 21 and 28. The primary endpoint of the study was to determine whether there is a dose response in the change in serum phosphorus from Baseline to Day 28 in the ITT group, using a regression analysis to evaluate this objective. The study met this primary endpoint, with the regression analysis indicating a highly statistically significant dose response (p<0.0001).  

Zerenex is an oral, iron-based compound that has the capacity to bind to phosphate and form non-absorbable complexes.

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