Keryx Biopharmaceuticals Announces Completion of Patient Enrollment in Zerenex(TM) (Ferric Citrate) Phase 3 Long-Term Study

NEW YORK, Sept. 19, 2011 /PRNewswire/ -- Keryx Biopharmaceuticals (Nasdaq: KERX) today announced completion of patient enrollment in the long-term study component of its Phase 3 registration program of Zerenex, the Company's ferric iron-based phosphate binder for the treatment of elevated serum phosphorus levels, or hyperphosphatemia, in patients with end-stage renal disease (ESRD) on dialysis. The Zerenex Phase 3 registration program, which is being conducted pursuant to a Special Protocol Assessment (SPA) with the Food and Drug Administration (FDA), is comprised of an already successfully-completed Phase 3 short-term study, and this ongoing Phase 3 long-term study.

This Phase 3 long-term study is a multicenter, randomized, open-label, safety and efficacy clinical trial in over 400 ESRD patients on hemodialysis or peritoneal dialysis. The study consists of a 2-week washout period followed by a 52-week safety assessment in which patients are randomized 2:1 to receive either Zerenex or an active control. The 52-week safety assessment period is followed by a 4-week efficacy assessment. During the 4-week efficacy assessment, only those patients randomized to treatment with Zerenex during the safety assessment period will be randomized in a 1:1 ratio to either continue treatment with Zerenex or to be switched to placebo for a 4-week period.

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, is the Study Chair of the Zerenex Phase 3 registration program. Dr. Samuel S. Blumenthal, Professor of Medicine at Medical College of Wisconsin, is the study's Co-Principal Investigator.

Ron Bentsur, Chief Executive Officer of Keryx, commented, "We are pleased to have completed patient enrollment into the Zerenex Phase 3 long-term study, over-enrolling slightly to meet patient and physician interest in the study. We remain grateful to the investigators for their continued dedication and commitment to the clinical development of Zerenex."

In April 2011, the Company reported the positive final dataset from the Zerenex Phase 3 short-term study.

Keryx holds a worldwide license (except for certain Asian Pacific countries) to Zerenex (ferric citrate) from Panion & BF Biotech, Inc. The Japanese rights are sublicensed by Keryx to Japan Tobacco Inc. and Torii Pharmaceutical Co., Ltd.

About Special Protocol Assessments

The Special Protocol Assessment (SPA) process is a procedure by which the FDA provides official evaluation and written guidance on the design and size of proposed protocols that are intended to form the basis for a new drug application.

Final marketing approval depends on the efficacy and safety results, including the adverse event profile, and an evaluation of the benefit/risk of treatment demonstrated in the Phase 3 clinical program. The SPA agreement may only be changed through a written agreement between the sponsor and the FDA, or if the FDA becomes aware of a substantial scientific issue essential to product efficacy or safety. For more information on Special Protocol Assessment, please visit: http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm080571.pdf.

About Hyperphosphatemia

In the United States, according to data from the U.S. Renal Data System, there are approximately 548,000 patients with end-stage renal disease, or ESRD, and the number of ESRD patients is projected to rise over 40% to approximately 785,000 by 2020. The majority of ESRD patients, over 375,000, require dialysis. Phosphate retention and the resulting hyperphosphatemia in patients with ESRD on dialysis are usually associated with secondary hyperparathyroidism, renal osteodystrophy, soft tissue mineralization and the progression of renal failure. ESRD patients usually require treatment with phosphate-binding agents to lower and maintain serum phosphorus at acceptable levels. The need for alternative phosphate-binding agents has long been recognized, especially given the increasing prevalence of ESRD as well as shortcomings with current therapies. Zerenex has the potential to be an effective and safe treatment in lowering and/or maintaining normal serum phosphorus levels in patients with ESRD and hyperphosphatemia.

The market for phosphate binders to treat hyperphosphatemia in ESRD patients in 2010 was approximately $750 million in the U.S. and is approaching $1.5 billion worldwide.

About Keryx Biopharmaceuticals, Inc.

Keryx Biopharmaceuticals is focused on the acquisition, development and commercialization of medically important pharmaceutical products for the treatment of cancer and renal disease. Keryx is developing KRX-0401 (perifosine), a novel, potentially first-in-class, oral anti-cancer agent that inhibits Akt activation in the phosphoinositide 3-kinase (PI3K) pathway, and also affects other signal transduction pathways, including the JNK pathway, believed to be associated with cell death, growth, differentiation and survival. KRX-0401 is currently in Phase 3 clinical development for both refractory advanced colorectal cancer and multiple myeloma, and in Phase 1 and 2 clinical development for several other tumor types. Each of the KRX-0401 Phase 3 studies is being conducted under a Special Protocol Assessment (SPA) agreement with the Food and Drug Administration (FDA). Keryx is also developing Zerenex (ferric citrate), an oral, ferric iron-based compound that has the capacity to bind to phosphate and form non-absorbable complexes. The Phase 3 clinical program of Zerenex in the treatment for hyperphosphatemia (elevated phosphate levels) in patients with end-stage renal disease is being conducted pursuant to an SPA agreement with the FDA. Keryx is headquartered in New York City.

Cautionary Statement

Some of the statements included in this press release, particularly those anticipating future clinical trials and business prospects for Zerenex (ferric citrate) may be forward-looking statements that involve a number of risks and uncertainties. For those statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. Among the factors that could cause our actual results to differ materially are the following: our ability, and our Japanese partner's ability, to successfully and cost-effectively complete clinical trials for Zerenex (ferric citrate); uncertainties related to the regulatory process in the United States, Europe and Japan; and other risk factors identified from time to time in our reports filed with the Securities and Exchange Commission. Any forward-looking statements set forth in this press release speak only as of the date of this press release. We do not undertake to update any of these forward-looking statements to reflect events or circumstances that occur after the date hereof. This press release and prior releases are available at http://www.keryx.com. The information found on our website and the FDA website is not incorporated by reference into this press release and is included for reference purposes only.

KERYX CONTACT:
Lauren Fischer
Director - Investor Relations
Keryx Biopharmaceuticals, Inc.
Tel: 212.531.5965
E-mail: lfischer@keryx.com

SOURCE Keryx Biopharmaceuticals, Inc.