Keryx Hits Phase II Targets

Keryx Biopharmaceuticals has posted successful top-line results from its Phase II study of Zerenex (ferric citrate coordination complex) in non-dialysis dependent chronic kidney disease (NDD-CKD) patients with elevated serum phosphorus and iron deficiency anemia. In this study, Zerenex met both its co-primary endpoints,, demonstrating highly statistically significant changes in serum phosphorus and transferrin saturation (TSAT) versus placebo during the 12-week treatment period.

In addition, Zerenex met the key secondary endpoints of increasing ferritin and hemoglobin, and decreasing fibroblast growth factor-23 (FGF-23) versus placebo. The company plans to meet with the FDA to discuss these data with the goal of defining a path forward towards obtaining a labeled indication for the treatment of iron deficiency anemia in NDD-CKD patients.

The Phase II study was a multicenter, randomized, double-blind, placebo-controlled clinical trial in subjects with stage 3 to 5 NDD-CKD, with elevated serum phosphorus >=4.0 mg/dL and iron deficiency anemia. The study consisted of a two-week washout period (for subjects on a phosphate binder at screening) followed by a 12-week treatment period in which subjects were randomized 1:1 to receive either Zerenex or placebo. One hundred forty-nine subjects were randomized into the study from 20 sites in the U.S.

The co-primary efficacy endpoints of this trial were the mean changes in serum phosphorus and TSAT from baseline to the end of the 12-week treatment period versus placebo in the ITT group. Zerenex met both co-primary and all key secondary endpoints with highly statistically significant results. The Intent-to Treat (ITT) group included 141 subjects, representing all subjects who took at least one dose of Zerenex or placebo and provided at least one post-baseline efficacy assessment.

The company’s NDA for the use of Zerenex for the treatment of hyperphosphatemia in chronic kidney disease patients on dialysis is currently under review by the FDA with an assigned Prescription Drug User Fee Act (PDUFA) goal date of June 7, 2014.