Keryx Biopharmaceuticals, Inc. has submitted a new drug application (NDA) to the US Food and Drug Administration (FDA) for seeking approval for marketing and sale of its drug candidate Zerenex (ferric citrate coordination complex) for the treatment of elevated serum phosphorus levels, or hyperphosphatemia, in patients with chronic kidney disease (CKD) on dialysis.

The Company's NDA submission is based primarily on the datasets derived from its phase III registration programme, which was conducted pursuant to a Special Protocol Assessment (SPA) agreement with the FDA, and is also supported by efficacy and safety data from several additional studies, including four phase III studies conducted in Japan in CKD patients on dialysis.

Ron Bentsur, the Company's chief executive officer, said, "The submission of the Zerenex NDA marks a major milestone for the Company. With approximately 1,500 patients exposed to the drug in the clinical development programmes conducted by us and our Japanese partner, JT/Torii, we believe that Zerenex is a safe, effective and highly-differentiated drug candidate and today's submission brings us one step closer to potentially bringing this drug to patients who can benefit from it."  Bentsur continued, "We are grateful to Dr. Julia Lewis, the Study Chair for the Zerenex phase III programme, and to our highly skilled internal team of clinical, manufacturing and regulatory professionals, for the time and effort they have dedicated towards this tremendous achievement."

The Company also plans to submit a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) for regulatory approval of Zerenex in the European Union.

Keryx holds a worldwide license (except for certain Asian Pacific countries) to Zerenex from Panion & BF Biotech, Inc. The Japanese rights are sublicensed by Keryx to Japan Tobacco Inc. (JT) and Torii Pharmaceutical Co., Ltd. (Torii). On January 7, 2013, JT announced the filing of its NDA with the Japanese Ministry of Health, Labour and Welfare for marketing approval of ferric citrate in Japan for the treatment of hyperphosphatemia in patients with CKD.

Zerenex is also in phase II development in the US for the management of phosphorus and iron deficiency in anemic patients with Stage 3 to 5 non-dialysis dependent CKD.

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 III clinical programme. 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.

Keryx Biopharmaceuticals is focused on the acquisition, development and commercialization of medically important pharmaceutical products for the treatment of renal disease.