Doctrine of Equivalents in Lilly v. Apotex

Eli Lilly and Co v. Apotex, Inc. (Fed. Cir. 2020)

You don’t see this often — the district court held on summary judgment that Apotex infringes under the doctrine of equivalents.  On appeal, the Federal Circuit has affirmed – finding no error. (Nonprecedential opinion)

Lilly’s US7772209 claims a particular treatment scheme for pemetrexed disodium that includes a pre-treatment with folic-acid to avoid the harsh side-effects.  See, Crouch, Eligibility Cannot be Raised in IPR Appeal (2019).  Apotex’s product uses a slightly different salt – pemetrexed dipotassium.  Apotex needs its version to be the equivalent in order to receive drug approval, but it would prefer to still avoid infringement under the Doctrine of Equivalents.

Although Apotex (implicitly) admits that its version is an equivalent, the company argues that Lilly should be estopped from pursuing DoE infringement here because of Prosecution History Estoppel (PHE).  In particular, Lilly made a narrowing amendment to the claim term in question during patent prosecution to avoid the prior art and now seeks to reclaim that ground via equivalents.

My simplistic drawing above does the trick.  Lilly’s original patent filing did not expressly claim the use of “pemetrexed disodium,” but rather used the broader term “an antifolate.”  During prosecution, Lilly narrowed its claims to avoid some prior art — deleting the broader “antifolate” limitation and replacing it with the narrower “pemetrexed disodium.”

None of the dependent claims expressly recited Pemetrexed Disodium.  However, one original claim had limited the antifolate to “ALIMTA,” which is Lilly’s brand of Pemetrexed Disodium.  In addition, the specification noted that the “most preferred” antifolate for the practicing the invention is “Pemetrexed Disodium (ALIMTA), as manufactured by Eli Lilly & Co.”  The claim to ALIMTA was also deleted during prosecution based upon an indefiniteness rejection. MPEP 2173.05(u).

PHE: We know that a narrowing amendment made during prosecution creates a presumption of Prosecution History Estoppel that would bar the patentee from asserting infringement-by-equivalents over the surrendered subject-matter.

The district court found no surrender, and the Federal Circuit affirmed.  The first bit here is easy claim construction — the original (dependent) claim recited “ALIMTA” and now the claim recites “pemetrexed disodium.”  The district court found these to be synonymous, and the federal circuit agreed.  Apotex had argued that ALIMTA should have been seen as encompassing all forms of pemetrexed, and thus its deletion would serve as an additional narrowing amendment. The courts, however, rejected that argument based upon in intrinsic evidence within the patent documents.  This was the sole argument raised on appeal by Apotex and thus lost the case.

The court does not address PHE stemming from the bigger amendment (antifolate => pemetrexed disodium).  There was a continuation application in-between, but you “can’t use continuations to avoid fact of narrowing amendment.” Robert A. Matthews, 2 Annotated Patent Digest § 14:82.

13 thoughts on “Doctrine of Equivalents in Lilly v. Apotex

  1. 3

    There is something very odd about this case and the facts recited in the decision. There was an obvious narrowing amendment of “an antifolate” to “pemetexed disodium”, but, based on reading the decision, this was never argued or presented in court as creating prosecution history estoppel that would limit the doctrine of equivalents. Why not? It clearly narrows the claim scope from all antifolates to a single one. The argument that the trademark name was narrowing compared to the name of the API seems specious especially in light of how the specification equated the trademark with a very specific compound manufactured by a specific company.

    1. 3.2

      My understanding of the argument is that the granted claim reciting pemetrexd disodium is equivalent to the original dependent claim to ALIMTA. The original dependent claim to ALIMTA can be infringed under the DoE, and so does the granted claim.
      In the current state of the DoE, amendments by inclusion of all the limitations of a dependent claim are not treated like narrowing amendments of a claim based on a passage in the written description, because the former correspond to a claim originally filed, a later is not. All the claims originally filed can be infringed under the DoE.

      1. 3.2.2

        If the amendment didn’t change the actual claim scope, how did it overcome the prior art?

    2. 3.3

      Because the Federal Circuit had already found in Eli Lilly v. Hospira, Inc, 933 F.3d 1320, 1325–26 (Fed. Cir. 2019) that Eli Lilly’s amendment from antifolate to “pemetrexed disodium” was tangential to pemetrexed ditromethamine.

  2. 2

    If you are interested in prosecution history estoppel issue from the amendment from antifolate to pemetrexed disodium, the Federal Circuit addressed it last year in a published opinion. Eli Lilly v. Hospira.

  3. 1

    Exactly this case has been litigated all over Europe up to national Supreme Court level and I have been curious, all through, about one aspect. I ask readers here to enlighten me, if only because my curiosity is about a claim drafting issue and the patent was drafted in the USA.

    As the Dennis diagram shows, the claim term “antifolate” was too wide. But what if the application as filed had included an independent claim 1, couched at the level of “antifolate”, such claim being followed by dependent claim 2, to pemetrexed salt, followed by claim 3, dependent on claim 2, to pemetrexed disodium? The European litigation suggests that claim 2 would have been found NOT to be invalid, and YES, directly infringed.

    Is there some reason, other than incompetence, why my claim 2 was not included, from the outset? People in Europe surmise that it would have failed, for lack of sufficient supporting disclosure in the specification as filed but I don’t buy that. Should I? Or is there some other explanation?

    1. 1.1

      Had it been included from the actual outset – i.e. the application as filed – it would not pose a problem in Europe. The fact that it wasn’t appears to be a drafting error, IMO.

      1. 1.1.1

        A drafting deficiency, indeed. Another one was in the Chef America case, wasn’t it. The difference though, is in the degree to which the patent owner was punished for the deficiencies of their drafter. A trivial deficiency gets disproportionately punished, while a gross deficiency gets forgiven, even rewarded.

        Bit of a lottery, eh, whether the drafting deficiency leads to i) loss of all protection or ii) a scope of protection grossly greater than the actual words of the claim would dictate?

        Bit like the banks, eh? They too can be “Too Big to Fail”. Adam Smith, unequivocal in his passionate warnings about the dangers to prosperity of lobbyism and crony capitalism, Adam Smith, the champion of fair and progressive taxation and the legal certainty of justice for all, no matter how big or small, will be spinning in his grave.

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