On January 4, 2017, in a final written decision in IPR2015-01490, the PTAB found 17 claims of a patent directed to methods of treating iron disorders by administering certain iron carbohydrate complexes were unpatentable. Further, the PTAB rejected a contingent motion to amend the claims.

U.S. Patent No. 7,754,702, owned by Luitpold Pharmaceuticals, is directed to the treatment of iron disorders with iron carbohydrate complexes that have a substantially non-immunogenic carbohydrate component, which provides for a markedly lower incidence of anaphylaxis upon administration than prior iron dextran complexes, and which can be administered at dosages far higher than contemplated by current protocols.

The PTAB agreed with Petitioner Pharmacosmos A/S’s assertion that several claims were anticipated by WO 2004/037865 (“Geisser”), which disclosed treatment using iron-carbohydrate complexes, including a carboxymaltose-iron complex, having a reduced risk of anaphylactic shock. The PTAB rejected the Patent Owner’s arguments that Petitioner did not demonstrate that Geisser teaches “a substantially nonimmunogenic carbohydrate component and substantially no cross reactivity with anti-dextran antibodies” as recited in the claims. In particular, the PTAB found that since Geisser teaches one of the iron carbohydrate complexes explicitly recited in the claims, iron carboxymaltose, it would inherently meet the functional limitations of the claims. The PTAB also found certain claims to be obvious based on various other prior art combinations, but was not persuaded that the Petitioner had met its burden to show that two claims—one directed to “adminster[ing] [a single dosage] in about 15 minutes or less” and one directed to “intravenously inject[ing] as a bolus”—were rendered obvious by the prior art.

The PTAB rejected Patent Owner’s motion to amend its claims to include the limitation “wherein the iron carbohydrate complex comprises an iron core with a mean iron core size of no greater than about 9 nm.” Although the PTAB found that the claims were not broadened and the limitation was supported by the written description, it further found that the cited references rendered the proposed substitution obvious.

This decision illustrates that merely appending inherent functional limitations to a claim directed to known compounds or structures will not be enough to survive a patentability challenge. The decision further illustrates the difficulties in amending claims during post-grant proceeding.