“Merely Tangential” Exception to Prosecution History Estoppel Saved “Inartful” Amendment from Barring Infringement by Equivalents

In Eli Lilly and Co. v. Hospira, Inc., [2018-2126, 2018-2127] (August 9, 2019), the Federal Circuit reversed the district court’s finding of literal infringement in the Hospira Decision as clearly erroneous in light of the court’s claim construction of “administration of pemetrexed disodium,” but affirmed the district court’s finding of infringement under the doctrine of equivalents.

Lilly markets the compound pemetrexed in the form of a disodium salt as Alimta®, for treating certain types of non-small cell lung cancer and mesothelioma. This product was covered by U.S. Patent 7,772,209. Hospira and Dr. Reddy’s each filed ANDA applications to market competing

With respect to the finding of literal infringement, Hospira argued that it cannot literally infringe the claims of the ’209 patent because intravenous administration of pemetrexed ditromethamine dissolved in saline—a solution which contains pemetrexed and chloride anions alongside sodium and tromethamine cations—is not “administration of pemetrexed disodium.” The Federal Circuit agreed, finding that “[i]t was clearly erroneous for the district court to hold that the ‘administration of pemetrexed disodium’ step was met because Hospira’s pemetrexed ditromethamine product will be dissolved in saline before administration. A solution of pemetrexed and chloride anions and tromethamine and sodium cations can-not be deemed pemetrexed disodium simply because some assortment of the ions in the solution consists of pemetrexed and two sodium cations.” The Federal Circuit concluded that to literally practice the “administration of pemetrexed disodium” step under the district court’s claim construction, the pemetrexed disodium salt must be itself administered.

With respect to the Doctrine of Equivalaents, the main dispute was whether prosecution history estoppel prevented Lilly from claiming that the administration of pemetrexed ditromethamine was an infringing equivalent to administering pemetrexed disodium. During prosecution, Lilly amended the claims from “an antifolate” to “pemetrexed disodium.” Lilly conceded that this was a narrowing amendment, and that it was made for reasons of patentability. However, Lilly argued that the rationale of its amendment bore “no more than a tangential relation to the equivalent in question.”

Lilly argued that the district court properly held that the reason for its amendment was to distinguish pemetrexed from antifolates generally and that the different salt type is a merely tangential change with no consequence for pemetrexed’s administration or mechanism of action within the body. The Federal Circuit agreed with Lilly. Noting that “tangential” meant “touching lightly or in the most tenuous way,” the Federal Circuit said that the reason for the amendment was to distinguish methotrexate. Under these circumstances the particular type of salt to which pemetrexed is complexed relates only tenuously to the reason for the narrowing amendment, which was to avoid methotrexate . The Federal Circuit therefore held that Lilly’s amendment was merely tangential to pemetrexed ditromethamine because the prosecution history, in view of the ’209 patent itself, strongly indicates that the reason for the amendment was not to cede other, functionally identical, pemetrexed salts.

The Federal Circuit also found support in the prosecution record, noting that Lilly’s amendment, inartful though it might have been, was prudential in nature and did not need or intend to cede other pemetrexed salts. Because the references specifically mentioned pemetrexed the Federal Circuit saiad that narrowing “antifolate” to “pemetrexed disodium” could not possibly distinguish the art cited in the obviousness ground of rejection.

Lilly’s burden under Festo was to show that pemetrexed ditromethamine was “peripheral, or not directly relevant,” to its amendment, and the Federal Circuit concluded it had done so.

The Federal Circuit also rejected arguments that the disclosure-dedication rule prevented a finding of infringement under the docitrine of equivavlents, agreeing with Lilly that the ’209 patent does not disclose methods of treatment using pemetrexed ditromethamine, and, as a result, Lilly could not have dedicated such a method to the public.

Because neither prosecution history estoppel nor the disclosure-dedication rule bars Lilly from asserting infringement through equivalence, the Federal Circuit affirmed the judgement of infringement.

Amendment of Claims in Parent Application Do Not Apply to Continuation Claims that do not have the Amended Language

In Sanofi v Watson Laboratories, Inc., [2016-2722, 2016-2726](November 9, 2017), the Federal Circuit affirmed the district court’s final judgment rejecting the obviousness challenge to claims 1–6, 8–13, and 16 of the U.S. Patent No. 8,410,167; finding inducement of infringement, by both
defendants, of all of those claims except claim 5; and finding infringement by both defendants of claims 1–3, 5-9, and 12–15 of U.S. Patent No. 8,318,800, and by Watson of claims 10 and 11 as well.

On appeal, Watson and Sandoz challenge the district court’s inducement
finding as to the ’167 patent, the district court’s rejection of their obviousness challenge to that patent, and the district court’s rejection of their prosecution disclaimer argument for limiting the scope of the ’800
patent claims.

On the inducement issues, the Federal Circuit said that it reviews the district court’s finding of inducement based on encouragement and inferred intent for clear error, which the Federal Circuit found was absent.  The Federal Circuit noted that the label directed medical providers to information identifying the desired benefit for only patients with the patent-claimed risk factors.  The Federal Circuit rejected Watson and Sandoz argument that substantial noninfringing uses not forbidden by the
proposed labels prevented a finding of intent to encourage an infringing use.  The Federal Circuit found no legal or logical basis for the suggested limitation on inducement.

On the obviousness issue, Watson and Sandoz only challenged the district court’s finding of no expectation of success.  The Federal Circuit said that although the evidence might well have supported the opposite finding, it could not conclude that the district court clearly erred in its finding.

On the infringement issue, the Federal Circuit rejected the argument that Watson and Sandoz  that the district court erred by failing to limit
the claims of the ’800 patent to exclude polysorbate surfactants.  While while prosecuting the parent application, which issued as U.S. Patent No. 7,323,493, Sanofi amended the sole independent claims
(hence all claims)f so as expressly to exclude pharmaceutical
compositions with a “polysorbate surfactant.”  Based on that amendment,
Watson and Sandoz contend that Sanofi made a “prosecution
disclaimer” that also limits the scope of the claims of the ’800 patent, despite the absence of any limiting language in the ’800 patent’s claims.

The Federal Circuit said that a prosecution disclaimer occurs when a patentee, either through argument or amendment, surrenders claim
scope during the course of prosecution.  But when the purported
disclaimers are directed to specific claim terms that have been omitted or materially altered in subsequent applications (rather than to the invention itself), those disclaimers do not apply.  The general ruling being that a prosecution disclaimer will only apply to a subsequent patent if that patent contains the same claim limitation as its predecessor.

The Federal Circuit observed that in prosecuting the application
that issued as the ’493 patent, was to write an express limitation into the claims: “provided that the pharmaceutical composition does not contain a polysorbate surfactant.” This language does not appear in the ’800 patent claims at issue, and Sanofi did not argue during prosecution that the unamended claim language of the ’493 patent, or the disclosed invention generally, excluded polysorbate surfactants.  The Federal Circuit said that the prosecution followed a familiar pattern:

an applicant adopts an explicit claim-narrowing limitation to achieve immediate issuance of a patent containing the narrowed claims and postpones to the prosecution of a continuation application further arguments
about claims that lack the narrowing limitation.

The Federal Circuit said that without more than exists here, that process does not imply a disclaimer as to claims, when later issued in the continuation, that lack the first patent’s express narrowing
limitation.  The Federal Circuit affirmed the district court’s ruling that the
scope of the claims of the ’800 patent should not be limited so as to exclude polysorbate surfactants.