Keryx Biopharmaceuticals Falls on Questions About Zerenex Market Exclusivity

Published: Feb 04, 2013

Move over Amarin (AMRN_), you have company on the "NCE worry" bus. Keryx Pharmaceuticals (KERX_) shares fell 22% to $7.11 Friday after an independent research firm raised questions about the company's ability to convince FDA to grant New Chemical Entity status to its experimental iron-based phosphate binder Zerenex. IPD Analytics, which conducts intellectual property healthcare research for Wall Street investors, issued its Keryx report on Friday. The IPD report also questioned the strength of Keryx's patents protecting Zerenex from potential generic competitors. Keryx shares have more than doubled since Jan. 28 when positive results from a long-term safety study of Zerenex were released. Keryx intends to seek U.S. and European approval for Zerenex, which would be used to lower blood levels of phosphorous in patients undergoing kidney dialysis. Zerenex may have a commercial advantage over other so-called phosphate binders because its iron-based core appears to reduce the need for intravenous iron and expensive anemia-boosting drugs like Amgen's (AMGN_) Epogen. The IPD report issued Friday speculates that the active ingredient in Zerenex may not be differentiated enough from Ferriseltz, developed by the Japanese drugmaker Otusuka and FDA approved in 1997 for use during MRI procedures. If FDA finds the active ingredients similar, Keryx could be denied NCE status and the five years of market exclusivity that goes with the designation. Without the protection of an NCE designation, generic filers could also file faster challenges to Zerenex.

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