In Hospira, Inc. v. Fresenius Kabi USA, LLC, the Fed. Cir. affirmed the District Court’s conclusion of obviousness based on factual findings which were not clearly erroneous.  The claim as issue in this ANDA litigation was directed to a ready to use liquid pharmaceutical composition of dexmedetomidine disposed within a sealed glass container, at a concentration of about 4 µg/mL having a loss of storage after five months of no more than 2%.  Concentrated formulations at 100 µg/mL and 500 µg/mL were reported, the more concentrated composition reporting a two-year self-life.  The concentrates were used to prepare formulations at 4 µg/mL, prior to intravenous administration as a sedative.  Patentee argued that the claimed premix avoided the need for dilution and demonstrated storage stability under different storage conditions, under different stresses and that oxidative conditions showed the highest amount of degradation.  A preparative example prepared with nitrogen sparging was provided.  The district court found a concentration of 4 µg/mL to be taught in the art and that a stability of no more than 2% was inherent to 4 µg/mL samples citing test samples from patentee’s NDA and Fresenius’s expert’s testimony that dexmedetomidine stability was concentration independent.  Fresenius’s expert was found to be more reliable than Hospira’s expert.  The district court also found the claimed stability to have been expected based on their understanding of the chemical properties of dexmedetomidine. 

Citing Par Pharm. v. TWI Pharm., Inc the Fed. Cir. stated that inherency is established when the limitation at issue necessarily must be present or the natural result of the combination of elements disclosed in the art.  The Fed. Cir. rejected Appellant’s argument that 1) non-prior art embodiments were considered and 2) the reasonable expectation standard was improperly used rather than the “necessarily present” standard.  The Fed. Cir. found no error in relying on non-prior art samples to demonstrate what is “necessarily present” as helping to elucidate what the prior art consisted of, and that manufacturing process details were irrelevant to composition claims.  The Fed. Cir. dismissed the district court’s conflation of the standard for inherency with a reasonable expectation of success as harmless error. This decision is consistent with their decision relating to inherent pharmacokinetics. Persion Pharmaceuticals LLC v. Alvogen Malta Operations Ltd.,

When claiming properties to distinguish from cited art, take care to consider whether the property necessarily flows from the combination, even when the property is not disclosed.  Would the result be different if the property limitation was introduced to address a commensurate in scope argument?