Keryx Biopharmaceuticals reaches SPA agreement for Phase 3 clinical program for Zerenex

Keryx Biopharmaceuticals, Inc. (Nasdaq: KERX) announced today that it has reached agreement with the U.S. Food and Drug Administration (FDA) regarding a Special Protocol Assessment (SPA) on the design of a Phase 3 clinical program for Zerenex(TM) (ferric citrate), its iron-based phosphate binder for the treatment of elevated serum phosphorous levels, or hyperphosphatemia, in patients with end-stage renal disease (ESRD). The SPA provides agreement that the Phase 3 program design adequately addresses objectives in support of a regulatory submission for drug approval.

In accordance with the Company's SPA agreement with the FDA, the Phase 3 clinical program for Zerenex will consist of two clinical studies, as follows:

• Short-term efficacy study: A multicenter, randomized, open-label clinical trial with a planned enrollment of approximately 150 patients on hemodialysis, who will be randomized to fixed doses of Zerenex, ranging from 1 gram per day to 8 grams per day, for a treatment period of 28 days. Patients will undergo a 2-week washout period prior to randomization. The primary endpoint of the study will be 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). This short-term study is expected to commence by the end of the first quarter of 2010, with data expected in the second half of 2010.

• Long-term safety and efficacy study: A multicenter, randomized, open-label, safety and efficacy clinical trial with a planned enrollment of approximately 300 patients on hemodialysis or peritoneal dialysis. The long term study will consist of a 2-week washout period followed by a 52-week safety assessment in which patients will be randomized 2:1 to receive either Zerenex or the same dose of phosphate binder administered immediately prior to washout. The 52-week safety assessment will be followed by a 4-week efficacy assessment in which only patients randomized to treatment with Zerenex during the safety assessment will be randomized to continue treatment with either Zerenex or placebo for a 4-week period. The long-term study is expected to begin in mid-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 program. Dr. Lewis commented, "We are extremely excited to be leading this clinical program for Zerenex, which we believe is a differentiated, iron-based phosphate binder. The data accumulated to date suggests that Zerenex is an effective, tolerated phosphate binder, and, given the growing market and limitations of the currently marketed drugs for hyperphosphatemia, we believe that Zerenex, which is not polymer-based and is free of aluminum, lanthanum, and calcium, will potentially make a significant clinical addition to treating the important universally present problem of hyperphosphatemia in patients with end-stage renal disease."

Ron Bentsur, Chief Executive Officer of Keryx, stated, "The Zerenex SPA agreement is a major milestone which provides us with a clearly defined development and regulatory pathway for Zerenex in the treatment of hyperphosphatemia, and we would like to thank the FDA for its invaluable guidance throughout this process." Mr. Bentsur continued, "With two Phase 3 drug candidates, Zerenex and Perifosine, both with SPA agreements in place, we believe that Keryx is well positioned to unlock significant shareholder value in 2010."