A move towards a doctrine of equivalents? – Eli Lilly v Actavis

The Supreme Court has indicated in Eli Lilly v Actavis that the term “disodium salt” should be interpreted to also cover the dipotassium salt.

The Supreme Court has issued an important decision on whether literal infringement is required or whether an equivalent will infringe. The tests set down under the Improver case have been reconsidered and modified, with guidance given in particular to the proper application of the third question.

Facts and History

On the face of it, the Eli Lilly v Actavis case seems straightforward. Eli Lilly is the proprietor of European patent No. 1313508 which claims:-

“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, said pharmaceutical derivative of vitamin B12 being hydroxocobalamin, cyano-10-chlorocobalamin, aquocobalamin perchlorate, aquo-10-chlorocobalamin perchlorate, azidocobalamin, chlorocobalamin or cobalamin.”

“A product containing pemetrexed disodium, vitamin B12 or a pharmaceutical derivative thereof said pharmaceutical derivative of vitamin B12 being hydroxocobalamin, cyano-10-chlorocobalamin, aquocobalamin perchlorate, aquo-10-chlorocobalamin perchlorate, azidocobalamin, chlorocobalamin or cobalamin, and, optionally, a folic binding protein binding agent selected from the group consisting of folic acid, (6R)-5-methyl-5,6,7,8-tetrahydrofolic acid and (6R)-5-formyl-5,6,7,8-tetrahydrofolic acid, or a physiologically available salt or ester thereof, as a combined preparation for the simultaneous, separate or sequential use in inhibiting tumor growth.”

Importantly both claims refer to the disodium salt of pemetrexed.

The Actavis product also includes pemetrexed in combination with vitamin B12 for cancer treatment, but the pemetrexed compounds include the free acid, the ditromethamine salt or the dipotassium salt thereof.

At first instance there was held to be no infringement. The Appeal was rejected with respect to direct infringement but allowed in respect of indirect infringement, where the compound is reconstituted in saline, resulting in the disodium salt.

The Supreme Court Decision

The case was further appealed to the Supreme Court who allowed the appeal, holding that the Actavis products directly infringed Eli Lilly’s patent.

As there is clearly no literal infringement this result may seem surprising.

The relevant UK law, namely Section 60(1) of the Patents Act 1977 is “framed to have, as nearly as practicable, the same effects in the UK as the corresponding provision of the EPC”. Article 2 of the Protocol to Article 69 EPC requires that “for the purpose of determining the extent of protection conferred by a European patent, due account shall be taken of any element which is equivalent to an element specified in the claims”.

Lord Neuberger gave the principle judgement and noted that Article 2 of the protocol is clearly a compromise and indicates that the scope of protection is not limited to the literal meaning of the claims, without making it clear how far away from the literal meaning the court can consider.

The Improver Questions

In his Decision relating to whether a “coiled helical spring” was infringed by a coiled slotted rubber rod which worked in the same manner, Hoffmann J (as he then was) developed the following test:-

“If the issue was whether a feature embodied in an alleged infringement which fell outside the primary, literal or contextual meaning of a descriptive word or phrase in the claim (‘a variant’) was nevertheless within its language as properly interpreted, the court should ask itself the following three questions:

  1. Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim. If no –
  2. Would this (i.e. 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 of 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”.

In later judgement, Lord Hoffmann (as he had then become) reconsidered this issue and reasserted the above questions, suggesting that the Protocol was “intended to give the patentee the full extent, but no more than the full extent, of the monopoly which a reasonable person skilled in the art, reading the claims in context, would think he was intending to claim”.

The ‘Improved’ Improver Questions

Lord Neuberger considered that the correct approach was to consider two separate issues:-

  1. Does the variant infringe any of these claims as a matter of normal interpretation; and if not
  2. Does the variant nonetheless infringe because it varies from the invention in a way or ways which is or are immaterial.

These issues are separate and are not simply a question of interpretation of the claims. As a result, while the Improver questions provide some assistance in this matter, they require some re-wording, in particular with regards to question 2. The new questions set forth are as follows:-

  1. Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, i.e. the inventive concept revealed by the patent?
  2. Would it be obvious to the skilled person 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?
  3. Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?

In relation to the present case the court provided further guidance on use of these questions and the considerations necessary.

The answer to the first two questions is clearly ‘yes’. However, in respect of the third question, Lord Neuberger considered it important not to give too much weight to the specific words used, and to give more weight to Article 2 of the Protocol; the risk being that of reverting to use of normal interpretation. He noted “if one cannot depart from the language of the claim […], what is the point of the questions in the first place? He then concluded that the reason why the claims were limited to the disodium salt was that this was the only pemetrexed compound on which experiments had been carried out, but this does not suggest that the patentee did not wish to cover any other compounds. Thus, the notional addressee would have concluded that the patentee would not have wished to exclude other pemetrexed compounds from the scope of protection.

Is this a Doctrine of Equivalents?

Despite not giving a green light to a full doctrine of equivalents, this decision does appear to provide a significant step in that direction.

New direction in how to use the third Improver question, and emphasis that it is not limited to the normal or literal interpretation of the language, appears to suggest that more emphasis will be given to the inventive concept and less to the wording of the claims.