This article was first published for ThePharmaLetter.
Mark Engelman, head of intellectual property at UK-based law firm Hardwicke, offers his interpretation on a landmark ruling in an Expert View piece.
Gorge Hegel, in his book Phänomenologie des Geistes (1807) asserted: “Absolute knowing is the truth of every mode of consciousness because… it is only in absolute knowing that the separation of the object from the certainty of itself is completely eliminated: truth is now equated with certainty and certainty with truth.”
This statement was in essence his central philosophy of realism. Whether reality exists or whether we merely perceive it. The concept is not a million miles away from a landmark judgement of the English Supreme Court in Actavis of July 12, 2017, upon the perennial issue surrounding the interpretation of patent claims. Freud’s Interpretation of Dreams might have proved a more reliable source of quotes. Freud considered images in dreams to be freighted with symbolic significance, the symbols or words themselves merely connectors and associations with other meanings.
In Actavis, a judgment concerning the claims to Eli Lilly’s (NYSE: LLY) drug pemetrexed, the Supreme Court in July was again required to revisit the House of Lords’ three previous judgments.
The first, Catnic Components Ltd v Hill & Smith Ltd  RPC 183, concerned claims over a the structure of a door lintel. There the court drew a distinction between “textual infringement” and “infringement of the ‘pith and marrow’ of the invention.” That Hegelian conflict was again recognized in the second case, Improver Corpn v Remington Consumer Products Ltd  FSR 181. It introduced a three-part test to the interpretation of patent claims, now known famously as “the Improver Questions”:
(1) Does a variant (to an element of a patent claim) have a material effect upon the way the invention works? If yes, the variant is outside the claim. If no…
(2) Would this (ie, that the variant had no material effect) have been obvious at the date of publication of the patent to a reader skilled in the art? If no, the variant is outside the claim. If yes…
(3) Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention? If yes, the variant is outside the claim.
On the other hand, a negative answer to the last question would lead to the conclusion that the patentee was intending the word or phrase to have not a literal, but a figurative meaning (the figure being a form of synecdoche or metonymy) denoting a class of things which included the variant and the literal meaning, the latter being perhaps the most perfect, best-known or striking example of the class.”
And finally, the most recent of the triptych, in Kirin-Amgen Inc v Hoechst Marion Roussel Ltd  RPC 9, rejecting literalism over a purposive construction: “to adopt a principle of construction which actually gave effect to what the person skilled in the art would have understood the patentee to be claiming”.
So what does all this have to do with pemetrexed?
Pemetrexed comprises an anitfolate in a disodium salt routinely used in the treatment of carcinoma.
The drug’s side effects alone are significant. However, these are ameliorated if administered with vitamin B12. Actavis intended to launch its drug which contained either (a) pemetrexed diacid, (b) pemetrexed ditromethamine, or (c) pemetrexed dipotassium but crucially not the disodium salt, the active component of Eli Lilly’s drug and the words to be found in Claim 1, the key claim of its patent.
Eli Lilly argued the Actavis equivalent infringed its patent either because it fell within the claims or because the disodium salt is created in the course of manufacturing pemetrexed. Claim 1 read:
“1. Use of pemetrexed disodium in the manufacture of a medicament for use in combination therapy for inhibiting tumor growth in mammals wherein said medicament is to be administered in combination with vitamin B12 or a pharmaceutical derivative thereof [which it then specifies].”
The central contention between Eli Lilly and Actavis was whether the words “pemetrexed disodium” were to be read literally or purposively? If the latter, they include either a pemetrexed diacid or a pemetrexed salt with vitamin B12, which represents the essence of the patent.
Article 60 of European Patent Convention (with which all EPC countries seek to conform) directs that in relation to European patents, one should not construe the words too literally nor too widely. Article 60 (2) of European Patent Convention introduces the “doctrine of equivalents”. Due account shall be taken of “any element which is equivalent to an element specified in the claims.”
Both Hegel and Freud would be pleased.
The Supreme Court now asked whether the three earlier House of Lords’ judgments in Catnic, Improver and Kirin-Amgen apply that test? Lord Neuberger, who gave the lead judgement, felt that the doctrine of equivalents should be distilled into five rather than three questions:
“(i) does the variant infringe any of the claims as a matter of normal interpretation; and, if not, (ii) does the variant nonetheless infringe because it varies from the invention in a way or ways which is or are immaterial? If the answer to either issue is “yes”, there is an infringement; otherwise, there is not.”
In order to determine whether an infringement is a “immaterial” one must return to the Improver questions but with a replacement to the second question, with:
ii) Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?
The subtlety in the reframing of the second Improver question would appear to accommodate the state of knowledge to be attributed to the person skilled in the art who would normally interpret the patent that the alleged infringing variant does what it says on the label, rather than requiring the skilled person to assess that issue. The intent was to reduce the burden on the patentee when proving his case for infringement.
Returning to the first Improver question:
Those chemical variants in Actavis' product: (a) pemetrexed diacid, (b) pemetrexed ditromethamine and (c) pemetrexed dipotassium were “equivalents” of the disodium salt. They did not have a material effect upon the way the invention works. Lord Neuberger considered that they did “substantially” the same thing as the disodium salt, namely render the combination of drug and vitamin B12 non-toxic. Lord Neuberger, having cemented the test, seemingly could not resist the implicit qualification of question one by the addition of the word “substantially”, another gloss upon an already complex five-part test.
Applying this to the second Improver question:
It would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention? Lord Neuberger found that too was answered in the affirmative. Here he overruled the Court of Appeal concerning the state of knowledge of the skilled person. They did not need to know whether pemetrexed diacid, pemetrexed ditromethamine or pemetrexed dipotassium actually worked when combined with vitamin B12, but could take that as a given.
Returning the last of the three Improver questions:
Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention? If yes, the variant is outside the claim, Lord Neuberger now engaged upon the Hegel’s potential dissonance between words and the meaning of words. Was the patentee intending his claims to be interpreted literally or illustratively?
The Court of Appeal below had held that the patent was clearly limited to the disodium salt, and did not extend to the diacid, or the dipotassium or ditromethamine salts”.
Lord Neuberger rightly pointed out that if literalism was the approach, there would be no need for the three Improver questions, only one. Returning to Eli Lilly’s patent, Lord Neuberger drew upon references in its specification to the words “other anti-folate drugs which have a similar effect to pemetrexed disodium”. In doing so he refused to take into account any exchanges between the patent office and the patentee during the prosecution of the patent. Eli Lilly was not intending that its patent be interpreted literally and pinned to its single reference to the words “pemetrexed disodium” in Claim 1.
This judgment is clearly paving the way to wider protection for patentees and a direction to patent attorneys to assist in that wider construction by mentioning equivalents as often as they can when drafting patent specifications, even though the invention teaches and claims only one such variant.
Freud said that when one dreams of a journey, one is dreaming of one’s fate, a transposition of the literal symbolism. One must be careful not to dream of anti-flolates.
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