Written Description: What Is the Proper “Dosage” to Satisfy This Requirement?

Knobbe Martens

Knobbe Martens


Before O’Malley, Reyna, and Hughes. Appeal from the United States District Court for the Northern District of West Virginia.

Summary: A specification may not describe “possession” of an invention in satisfaction of the § 112 written description requirement even though the specification lists dosage ranges encompassing the claimed limitation.

Biogen sued Mylan for infringement of a patent directed to a method of treating multiple sclerosis (MS) with dimethyl fumarate (DMF). Mylan counterclaimed asserting invalidity and non-infringement.  Claim 1 recites inter alia “wherein the therapeutically effective amount of [DMF]… is about 480 [milligrams] per day [DMF480].”  The patent specification recites inter alia “an effective dose of DMF… can be… from about 240 mg to about 720 mg per day; or from about 480 mg to about 720 mg per day; or about 720 mg per day.”  The district court found the asserted claims to be invalid for lack of written description because the specification failed to describe that the inventors possessed the claimed therapeutically effective dose of DMF to treat MS.  Biogen appealed.

The Federal Circuit affirmed invalidity based on a lack of written description.  First, the specification’s reference to DMF480 was part of a wide dosage range.  Specifically, DMF480 appeared in only a single range among multiple ranges and appeared at the end of that range.  The Federal Circuit contrasted this with the specification’s reference to DMF720 independently as a therapeutically efficacious dose.  Despite the wide range of potential doses, Biogen argued that a skilled artisan would be drawn to the DMF480 dose because it was “anchored” to the DMF720 dose, which was known at the time to be effective.  However, the Federal Circuit noted that the specification also “anchored” other doses to DMF720 that were known to be ineffective (e.g., DMF240) as well as doses that would far exceed therapeutic efficacy (e.g., DMF1,000).  The Federal Circuit further noted that one of the inventors stated that his research was not focused on informing the clinical dosing of DMF and “denied that his research could be extrapolated to a clinical dose of DMF.”  Moreover, Biogen’s expert conceded that the sole DMF-dosage paragraphs in the specification did not teach a person of ordinary skill in the art that DMF480 would be therapeutically effective for treating MS.  Finally, the Federal Circuit noted that the patent specification included only the single paragraph teaching potential DMF dosage levels and that this paragraph was not linked to the treatment of any specific disease (e.g., MS).

Judge O’Malley dissented arguing that the district court erred in applying judicial estoppel to prevent Biogen from arguing a distinction between clinical and therapeutics effects of DMF480.  Judge O’Malley asserted that this error led to a fundamental misunderstanding of what is claimed and impacted the district court’s obviousness and written description analysis.

DISCLAIMER: Because of the generality of this update, the information provided herein may not be applicable in all situations and should not be acted upon without specific legal advice based on particular situations.

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