NEW YORK, Sept. 23 /PRNewswire-FirstCall/ -- Keryx Biopharmaceuticals, Inc. (Nasdaq: KERX) today announced results of the Open Label Extension (OLE) trial of Zerenex (ferric citrate) for the treatment of elevated serum phosphorous levels, or hyperphosphatemia, in patients with end-stage renal disease (ESRD) on dialysis. The OLE trial, conducted in Taiwan, enrolled 29 of the 37 Taiwanese patients that had completed the randomized, multi-center, multi-national (United States and Taiwan) dose-ranging Phase 2 study. This OLE represents the first trial to examine the long-term safety and efficacy of Zerenex as a phosphate binder. The treatment period in all previous Zerenex Phase 2 clinical trials did not exceed 28 days.
The OLE trial provided for a daily dose, ranging from 2 to 6 g/day of Zerenex, for a period of up to one year following completion of the 28-day, dose-ranging Phase 2 study. The average duration of the patients' participation in the OLE trial was 306 +/- 85 days.
Data from the OLE trial indicate that the mean serum phosphorus level throughout the trial was 5.22 +/- 0.18 mg/dL, and the mean product of calcium times phosphate (CaxP) was 49.06 +/- 2.15 mg(2)/dL(2), both within the normal range as recommended by the KDOQI guidelines. In addition, during the OLE trial, the administration of IV iron as a supplement was withheld in 8 patients (27.6%) for periods ranging from 3 to 6 months and the administration of EPO was withheld in 8 patients (27.6%) for short periods because the hemoglobin, hematocrit, and iron parameters were within normal clinical ranges as assessed by the investigator. There were no signs of potential iron overload in the study patients, and there were no Zerenex-related serious adverse events as noted by either the patient or investigator.
Ron Bentsur, CEO of Keryx Biopharmaceuticals, stated, "We are very excited about this long-term data for Zerenex. The study suggests that Zerenex can maintain patients within the normal serum phosphorous range for extended periods of time and that the drug appears to be well-tolerated." Mr. Bentsur added, "We are also very encouraged by the emerging data suggesting that Zerenex may reduce the need for IV iron or EPO in this dialysis patient population, and should the results be replicated in the upcoming Phase 3 program, this could represent a significant clinical and cost advantage to the patient and the doctor."
ABOUT HYPERPHOSPHATEMIA
In the United States, according to data from the U.S. Renal Data System, there are approximately 485,000 patients with end-stage renal disease, or ESRD, and the number of ESRD patients is projected to rise 60% to approximately 785,000 by 2020. The majority of ESRD patients, over 350,000, require dialysis. Phosphate retention and the resulting hyperphosphatemia in patients with ESRD on dialysis are usually associated with secondary hyperparathyroidism (and its related cardiovascular complications), renal osteodystrophy and soft tissue mineralization. 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 the U.S. exceeded $600 million in 2008, and has grown approximately 25% per annum over the last five years.
