The U.S. Patent and Trademark Office has issued Keryx Biopharmaceuticals Inc. a new patent for ferric citrate that expires in 2024. The patent, number 8,846,976, claims a method of treating hyperphosphatemia comprised of 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 active pharmaceutical ingredient having an intrinsic dissolution rate of at least 1.88/mg/cm2/min. In addition, the patent contains claims directed to the FDA approved dosing and daily administration of the drug.

The FDA approved ferric citrate Sept. 5 to control serum phosphorus levels in patients with chronic kidney disease on dialysis. Keryx has recently started Phase 3 study of ferric citrate  to treat iron deficiency anemia in patients with non-dialysis dependent (Stage 3-5) chronic kidney disease.

Keryx has other patents for ferric citrate including 7,767,851, 8,299,298, 8,338,642, 8,609,896, 8,754,257 and 8,754,258, which expire in 2024, and U.S. Patent No. 8,093,423, which expires in 2028, before patent term extension.

“The novelty of our active ingredient is important because Patent Term Extension is granted for a drug if the drug’s active ingredient has not been previously approved by the FDA.” said Ron Bentsur, chief executive officer of Keryx. “To our knowledge, no other approved drugs contain tetraferric tricitrate decahydrate as the active ingredient.”