New Hyperphosphatemia Treatment Meets Phase III End Points

Keryx Biopharmaceuticals recently announced that the phase III clinical trial of its drug Zerenex (ferric citrate) successfully met its predetermined end points. Conducted under a Special Protocol Agreement, the study assessed the oral ferric iron–based compound for the treatment of hyperphosphatemia in patients with ESRD who are receiving dialysis.

The multicenter, randomized, open-label trial involved 441 patients with ESRD who were undergoing either hemodialysis or peritoneal dialysis. The study was conducted in two stages, a 52-week safety assessment phase and a 4-week efficacy assessment phase, preceded by a 2-week washout interval.

Zerenex met the primary end point of significantly reducing serum phosphorus levels compared to placebo in the efficacy assessment phase. The drug also met all secondary end points during the 52-week safety assessment, including maintenance of serum phosphorus in the normal range (with a noninferiority comparison with Renvela [sevelamer carbonate]), increasing ferritin and transferrin saturation levels, and reducing intravenous iron and erythropoiesis-stimulating agent use compared with the active control.

Based in New York City, Keryx also reported plans to file a New Drug Application for Zerenex with the Food and Drug Administration (FDA) and a Marketing Authorization Application with the European Medicines Agency in the second quarter of 2013.

The results of this trial follow the January 2013 announcement that Zerenex was submitted for approval in Japan by Japanese Tobacco, the company that sublicenses the drug from Keryx.

Current therapies for the treatment of hyperphosphatemia include Renvela and Renagel (sevelamer hydrochloride), both of which are manufactured by Sanofi.

Keryx has also initiated phase II development of Zerenex for the management of phosphorus and iron deficiency in patients with stage III–V CKD who are not receiving dialysis.

March 2013 (Vol. 5, Number 3)