On January 3, 2022, the Court of Appeals for the Federal Circuit (CAFC) affirmed the district court’s finding that a patent claim does not fail the written description requirement merely because the specification fails to explicitly state a negative claim limitation.  Novartis Pharmaceuticals v. Accord Healthcare Inc., No. 2021-1070 (Fed. Cir. Jan. 3, 2022).  

The written description requirement comes from the language of 35 U.S.C. § 112, which provides that a patent’s specification must contain “a written description of the invention, and of the manner and process of making and using it.”  Whether a claim satisfies this requirement is a question of fact reviewed for clear error.  Allergan, Inc. v. Sandoz Inc., 769 F.3d 12932, 1308 (Fed. Cir. 2015).  

This appeal involved a dispute in the Delaware District Court between Novartis, the owner U.S. Patent No. 9,187,405 directed towards the use of fingolimod hydrochloride in the treatment of relapsing remitting multiple sclerosis (“RRMS”), and HEC Pharm USA Inc., which sought to market a generic version of the drug.  At issue was claim 1, which recited the administration of the drug for the treatment of RRMS “at a daily dosage of 0.5 mg, absent an immediately preceding loading dose regimen.”  

The specification describes the results of an experiment in rats that were administered the drug after being induced with a disease that mimics RRSS.  The specification reports that disease relapse was completely inhibited in rats to which the drug was “administered daily at a dose of 0.3 mg/kg” or “administered p.o. at 0.3 mg/kg every 2nd or 3rd day or once a week.”  It then described a prophetic human trial in which RRMS patients would receive 0.5, 1.25, or 2.5 mg per day for two to six months.  No loading dose or lack of a loading dose was described.  

HEC Pharm USA argued that the specification could not support a claim limitation requiring there be no “immediately preceding loading dose regimen” because “silence alone cannot serve as a basis” for a negative claim limitation under the written description requirement.  It further argued that the finding of the district court to the contrary was inconsistent with its decision that a prior art abstract, which similarly failed to mention the presence or lack of a loading dose regimen, did not anticipate the claims.  

vThe CAFC rejected both arguments.  While acknowledging that “the mere absence of a positive recitation” is not enough and that “silence alone is insufficient,” the CAFC emphasized that the written description must be read for what it conveys to a person having ordinary skill in the art.   In this case, both the CAFC and the district court credited Novartis’s expert witness, who testified that a person having ordinary skill in the art would have expected a loading dose to be mentioned in the description of the prophetic human trial if one were required.  Moreover, this was not inconsistent with the decision on the prior art abstract because, as the expert opined, an abstract is not a “complete” document like a patent specification.  And a person having ordinary skill in the art would not necessarily expect a loading dose to appear in an abstract, even if one was required.

Having examined the record, and while cautioning that the Court did not intend to establish a new legal standard that silence is disclosure, the CAFC decided that the district court did not clearly err in finding the written description requirement satisfied.