Holding: External evidence may be considered to help understand how a person of ordinary skill in the art would interpret an alleged anticipatory reference.
All challenged claims of US Patent No. 10,398,642 and US Patent No. 10,688,067, owned by Sage, were found to be unpatentable in IPRs. These patents pertain to a sterilized chlorhexidine product contained in a package, such as an applicator filled with an antiseptic composition for disinfecting skin. The challenged claims each required a sterilized chlorhexidine gluconate composition. Some of the dependent claims required that the composition include a sterilized colorant or a sterility assurance level of from 10-3 to 10-9. The shared specification of the ‘642 Patent and the ‘067 Patent state that product is considered “sterilized” if its sterility can be validated. Sterilization methods mentioned in the specification include heat and radiation treatment.
The main piece of prior art relied upon by the PTAB was a ChloraPrep Public Assessment Report (“PAR”) produced by the UK Medicine and Healthcare Products Regulatory Agency. The PAR described the ChloraPrep product as including 20 mg/ml of chlorhexidine gluconate contained within an applicator that the user squeezes to break an interior ampoule of the solution to apply on the skin. The PAR includes required labeling which states that ChloraPrep is a sterile alcoholic antiseptic solution containing chlorhexidine gluconate and that the applicator is sterile until the packaging is opened. Although the PAR does not provide a definition for its use of the word “sterile,” the PTAB looked to British Standard EN-556-1, which establishes the UK’s requirements for labeling a medical device as being sterile. This standard specifies that the probability of a viable microorganism on the device must be equal to or less than 1 x 10-6 for a product to be labeled as sterile.
Sage argued that the PAR’s use of the term “sterile” was mistaken, since the ChloraPrep composition could be compromised when the glass ampule was broken during use. However, the PTAB disagreed and found that the PAR’s references to “sterile” disclosed a “sterilized” chlorhexidine gluconate product as claimed in the ‘642 Patent and the ‘067 Patent.
The Federal Circuit determined the findings of the PTAB were supported by substantial evidence. A person of ordinary skill in the art of sterilization processes would be familiar with the regulatory regimes in both the United States and the United Kingdom, and the difference between these regulatory standards for what makes a product “sterile.” This person of ordinary skill in the art would know that the PAR’s reference to “sterile” items would fall within the scope of the required “sterilized” compositions claimed in the ‘642 Patent and the ‘067 Patent.
Sage also argued that the PAR does not disclose the “sterilized colorant” limitation or that the sterilized chlorhexidine articles have a sterility assurance level of from 10-3 to 10-9. However, the Federal Circuit also upheld the PTAB’s finding that these limitations were anticipated by the prior art. Expert testimony established that any inactive ingredients included in ChloraPrep would have to be sterile for the PAR to describe the composition as sterile. Additionally, the EN-556-1 standard required a sterility assurance level of 10-6 or less.
Sage offered additional procedural arguments, asserting that the PTAB improperly established its own grounds and supporting arguments rather than limiting its evaluation to those asserted in the IPR petition. The Federal Circuit found that these arguments were largely the same factual challenges already presented reformed in procedural language. The PTAB had substantial evidence for its decision that a person of ordinary skill in the art would understand the use of the word “sterile” in the PAR to be the same as the “sterilization” limitation presented in the claims of the ‘642 Patent and the ‘067 Patent. The PTAB is allowed to investigate who the person of ordinary skill in the art is, as well as determine what the person of ordinary skill in the art would know. In coming to this determination, the PTAB may use evidence outside of the anticipating reference, such as expert testimony, to determine what a person of ordinary skill in the art would understand that reference to disclose.
Federal Circuit Precedential 
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