Keryx Biopharmaceuticals, a company focused on bringing innovative therapies to market for patients with renal disease, announced that the US Patent and Trademark Office issued US Patent No. 8,901,349.

The patent, which expires in 2024, claims a method of treating hyperphosphatemia comprising administering a therapeutically effective amount of an orally administrable form of ferric citrate to a subject, wherein the orally administrable form is prepared from a ferric citrate having a BET active surface area greater than about 16 sq. m/g. The patent also claims a broad category of orally administrable forms covering Auryxia, as well as other oral formulations that could be developed in the future.

On September 5, 2014, Auryxia (ferric citrate) was approved by the US Food and Drug Administration for the control of serum phosphorus levels in patients with chronic kidney disease (CKD) on dialysis.

This newly issued patent further enhances the Company's key patent family, which includes US Patent Nos. 7,767,851, 8,299,298, 8,338,642, 8,609,896, 8,754,257, 8,754,258, and 8,846,976 which expire in 2024, and US Patent No. 8,093,423, which expires in 2026, before patent term extension. Each of these patents contains composition and method of use claims covering Auryxia.

Ron Bentsur, chief executive officer of Keryx, commented, "The patent announced recently represents our fourth US patent issuance in 2014, and further fortifies the strength of our intellectual property position. This patent is significant in that it links orally administrable forms, including Auryxia, prepared from Keryx's unique API, having a surface area greater than about 16 sq. m/g." Bentsur added, "With the high surface area being a manufacturing specification for our API, we believe that the patent issued today provides another layer of substantial protection for Auryxia."

The Company continues to prosecute additional patent applications for Auryxia, which, if issued, would provide additional patent protection for Auryxia beyond 2030.  

In addition, the Company has filed its key patent families for Patent Term Extension, which, if granted, would add up to an additional 5 years to the patent protection for Auryxia. Following FDA approval, the FDA Substance Registration System adopted tetraferric tricitrate decahydrate as the name of the active ingredient approved for marketing by the FDA, to appropriately describe the Company's unique proprietary form of ferric citrate API.

Auryxia (ferric citrate) is an oral, absorbed, iron-based phosphate binder. In the United States, Auryxia was approved by the Food and Drug Administration (FDA) on September 5, 2014, for the control of serum phosphorus levels in patients with chronic kidney disease (CKD) on dialysis. Auryxia will be marketed in the US by Keryx Biopharmaceuticals, Inc. Keryx plans to make  Auryxia available to dialysis patients in the US this year.

In January 2014, ferric citrate was approved for the treatment of patients with all stages of CKD in Japan, where it is being marketed as Riona by Keryx's Japanese partner, Japan Tobacco Inc. and Torii Pharmaceutical Co. Ltd.

In March 2014, Keryx filed a Marketing Authorization Application (MAA) with the European Medicines Agency (EMA), seeking the approval of ferric citrate as a treatment of hyperphosphatemia in patients with CKD, including dialysis and non-dialysis dependent patients, and that application is currently under review.