Keryx Biopharmaceuticals commences Phase 3 registration program for Zerenex

Keryx Biopharmaceuticals, Inc. (Nasdaq: KERX) announced today the initiation of its short-term Phase 3 study of Zerenex™ (ferric citrate), the Company's iron-based phosphate binder for the treatment of elevated serum phosphorous levels, or hyperphosphatemia, in patients with end-stage renal disease on dialysis.  The initiation of this study marks the commencement of the Company's Phase 3 registration program for Zerenex, which is being conducted in accordance with a Special Protocol Assessment (SPA) agreement with the FDA.  Pursuant to the Company's SPA agreement, the Zerenex Phase 3 registration program will consist of the short-term efficacy study initiated today, and 58-week long-term safety and efficacy study, to be initiated in the third quarter of 2010.  Patients completing the short term study are eligible to be enrolled into the long-term study.

The short-term efficacy study initiated today is a multicenter, randomized, open-label clinical trial with a planned enrollment of approximately 150 patients on hemodialysis.  All patients will undergo a 2-week washout period, following which the patients will be randomized 1:1:1 to receive a fixed dose of Zerenex (1 gram, 6 grams or 8 grams per day) for a treatment period of 28 days.  The primary endpoint of the study is to demonstrate a dose response in the change of serum phosphorous from baseline (end of washout period) to end of the treatment period (day 28). Approximately 15 sites in the U.S. will participate in the study.  Patient enrollment is expected to take up to 6 months, with study completion expected by the end of 2010.

Dr. Julia Lewis, Professor of Medicine, Department of Nephrology, Vanderbilt University School of Medicine, and member of the Executive Committee of the Collaborative Study Group, will be the Study Chair of the Zerenex Phase 3 registration program.  Dr. Samuel S. Blumenthal, Professor of Medicine at Medical College of Wisconsin, will serve as the study's Co-Principal Investigator.

Dr. Julia Lewis commented, "I am pleased to be leading the registration program for Zerenex.  The clinical data generated to date suggests that Zerenex is an effective, safe and well-tolerated phosphate binder which we expect is differentiated from other marketed therapies by its iron composition and potential dosing convenience.  We are hopeful that this Phase 3 registration program of Zerenex will lead to a new treatment option for hyperphosphatemia benefiting patients with end-stage renal disease."

Ron Bentsur, Chief Executive Officer of Keryx , commented, "We are very excited about the initiation of the Zerenex Phase 3 program and look forward to generating Phase 3 data from this study later this year."  Mr. Bentsur, continued, "We believe that Zerenex could emerge with the attributes to capture meaningful market share in a worldwide phosphate binder market approaching $1.5 billion.  Finally, I want to thank the study investigators for their tremendous support and guidance."

Keryx expects to complete the Zerenex Phase 3 program and file a New Drug Application for Zerenex for the treatment of hyperphosphatemia in the first half of 2012.

Keryx Biopharmaceuticals retains a worldwide exclusive license (except for the Asian Pacific Region) to Zerenex (ferric citrate) from Panion & BF Biotech, Inc.  The Company has sublicensed the development of ferric citrate in Japan to Japan Tobacco Inc. and Torii Pharmaceutical Co., Ltd.