Disclosure-dedication doctrine dooms dramatic drug dispute despite declaration

Updated: Jul 28, 2020

Eagle Pharmaceuticals Inc.



Slayback Pharma LLC,



May 8, 2020

Case Summary

The Supreme Court’s 1997 Warner-Jenkinson decision explains that if an accused product does not literally infringe a patent claim, it may still be found to infringe under the doctrine of equivalents if “the accused product … contain[s] elements identical or equivalent to each claimed element of the patented invention.”

There are several limitations to this doctrine; one of these is articulated in the en banc Federal Circuit’s 2002 Johnson and Johnston decision, which prohibits a finding that an element in an accused product is equivalent to an element in an asserted claim if the claim’s specification: (a) discloses the element contained in the accused product; and (b) does not claim that element. This is now called the “disclosure-dedication doctrine.”

Defendant Slayback Pharma asserted a disclosure-dedication defense in a patent infringement action filed by Eagle Pharmaceuticals. The dispute began when Slayback filed a (with the FDA) new drug application for a generic version of Eagle’s branded bendamustine chemotherapy drug. Eagle then sued, alleging that Slayback’s drug infringed several claims that include the following limitations:

bendamustine (or one of its pharmaceutically acceptable salts);

a “pharmaceutically-acceptable fluid” comprising a mixture of polyethylene glycol and propylene glycol (with a range of acceptable ratios); and

a stabilizing amount of an antioxidant.

Slayback’s accused drug includes bendamustine and an antioxidant stabilizer, but it uses ethanol instead of the claimed “pharmaceutically-acceptable fluid” mixture of polyethylene glycol and propylene glycol; Eagle’s response was to argue that ethanol is equivalent to the polyethylene glycol/propylene glycol mixture.

Defendant Slayback’s motion to dismiss said that although the specification identifies ethanol as a substitute for the claimed polyethylene glycol/propylene glycol “pharmaceutically-acceptable fluid,” none of the claims recite drug compounds in which ethanol is the pharmaceutically-acceptable fluid; the disclosure-dedication doctrine therefore prohibits a finding that ethanol is equivalent to the claimed mixture.

The trial judge granted Slayback’s motion; Eagle’s position on appeal was that ­although the asserted patents’ specifications generally disclose (but do not claim) ethanol as a pharmaceutically-acceptable fluid, the disclosure-dedication doctrine does not apply because these patents do not disclose ethanol as an alternative to a polyethylene glycol/propylene glycol mixture for the claimed embodiment containing an antioxidant.

In rejecting this argument, the Federal Circuit said that the Johnson & Johnston decision “rejected this embodiment-level approach to the disclosure-dedication doctrine and denied the patentee's attempt to avoid dedication by claiming that the disclosure occurred in an ‘alternative [embodiment] distinct from the claimed invention.’” Instead, as the Court explained in its 2005 Pfizer decision, the disclosure-dedication doctrine requires only that the specification disclose the unclaimed matter “as an alternative to the relevant claim limitation.” The panel concluded its discussion of this issue by holding that “the asserted patents dedicated ethanol to the public by disclosing, but not claiming, ethanol as an alternative to [the polyethylene glycol/propylene glycol mixture] in the “pharmaceutically acceptable solvent” claim limitation.”

The appeals court also rejected Eagle’s assertion that the trial judge should have considered a declaration submitted by Eagle’s expert witness before ruling on the motion to dismiss. This declaration attempted to raise the factual issue of whether a skilled artisan would understand the specification to disclose ethanol as an alternative to the polyethylene glycol/propylene glycol mixture in the claimed embodiment that includes an antioxidant. By ignoring this declaration, Eagle said the trial judge erred by resolving that factual dispute at the pleadings stage without drawing all reasonable inferences in Eagle’s favor.

The panel again disagreed with the patent owner, noting that:

(a) “district courts have discretion to consider evidence outside the complaint for purposes of deciding whether to accept that evidence and convert the motion into one for summary judgment;”

(b) “expert testimony is not always required for a district court to determine how a skilled artisan would understand a patent’s disclosure and claimed invention;” and

(c) “the only reasonable inference that can be made from the patent disclosures is that a skilled artisan would understand the patents to disclose ethanol as an alternative to the claimed [polyethylene glycol/propylene glycol mixture].”

.05 Eagle Pharma v Slayback case sum

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