As previously reported, the Supreme Court of the United Kingdom have issued a landmark decision on patent infringement. The headline is that a doctrine of equivalents can now be said to apply in the UK and, moreover, apply to chemical subject matter.
In the case of Actavis vs. Eli Lilly, the Supreme Court decided that the scope of protection provided by Eli Lilly’s patent, the main claim of which specifies a disodium salt of the anti-cancer drug pemetrexed, covers inter alia Actavis’ dipotassium salt of the same drug.
This decision over-ruled the lower court’s decisions on the same issue and has changed the legal test for determining patent infringement in the UK. As a result, the scope of protection provided by many patents in the UK will now be broader, which will be an advantage for patentees. However, the decision will also increase uncertainty and costs for third parties wanting to establish their freedom to operate.
The reasoning behind the decision also highlights the gap that had existed between the UK and other countries in Europe in relation to patent infringement, a significant issue as we potentially move toward implementation of the Unitary Patent Court. It also demonstrates the controversial impact of the European Patent Office’s strict approach to added matter in relation to chemical patents.
In this article, we will provide analysis and explanation of these themes by explaining what has changed when it comes to assessing infringement in the UK and discussing the implications of those changes for patentees and third parties.
The previous UK approach
To determine the scope of protection provided by a patent, the patent claim must be interpreted. Does pemetrexed disodium cover only the disodium salt of pemetrexed or does it also cover the dipotassium salt?
Guidance for claim interpretation at the statute level is provided by Article 69 of the European Patent Convention (EPC)[1], which UK law applies. This Article provides that “the extent of the protection conferred by a European patent or European patent Application shall be determined by the claims. Nevertheless, the description and drawings shall be used to interpret the claims.” The Protocol on the Interpretation of Article 69 EPC further provides that the objective is to define a position which “combines a fair protection for the patent proprietor with a reasonable degree of legal certainty for third parties”[2].
In the 1982 Catnic decision, the House of determined that a literal interpretation of the claims was not appropriate[3]. According to the decision, a purposive construction should be applied to the claims, the tests set out were further codified in the Improver decision in 1990[4]. This was broadly the test applied in the UK to determine infringement until this Supreme Court decision.
Equivalents
In 2000 it was announced that a new Article, Article2, was to be added to the Protocol for the Interpretation of Article 69 EPC[5]. Article 2 provided 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.” (emphasis added).
This new article reflected an approach that many other European jurisdictions had been applying in addition to using a purposive construction. In these countries case law had developed so that “fair protection” for the patentee included covering embodiments having features which were “equivalent” to the feature of the claim, but which fell outside of the meaning of the claim as purposively interpreted.
Nevertheless, following the announcement that Article 2 was to be introduced, but before it came into force, a further significant UK decision, Kirin-Amgen, reinforced the existing purposive construction approach in the UK, and even commented that it was felt it satisfied the new Article 2[6]. Whether or not this was case, it became clear from contrasting decisions between the UK and other European countries that the infringement test applied by the UK could result in a narrower scope of protection in relation to the same patent.
In the present decision, Lord Neuberger has taken a different view to that expressed in Kirin-Amgen in relation to Article 2. He decided that the approach established in previous UK case law did not adequately account for equivalents and therefore did not satisfy Article 2. Accordingly, the Supreme Court has now provided a modified test for patent infringement in the UK.
The modified infringement test
The modified test has two parts[7]. In the first part, a decision must be reached on whether the alleged infringement is within the scope of protection provided by the claims based on a literal construction. In the present decision, Lord Neuberger accepted that “there is no doubt that, according to normal principles of interpreting documents, the Actavis products do not infringe the Patent, as in no sensible way can … pemetrexed dipostassium mean, i.e. be said to fall within the expression, “pemetrexed disodium in claim 1 of the Patent”.[8]
In the second part of the test, an assessment to determine whether the alleged infringement is an equivalent is carried out. Under the modified test, an infringing “equivalent” is found if the alleged infringement:
(i) achieves substantially the same result in substantially the same way as the invention, i.e. the inventive concept revealed by the patent; and
(ii) it would 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; unless
(iii) such a reader of the patent would 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.
Step (i) – “the same way” and the “inventive concept”
There is currently only limited information to assess what it means for the alleged infringement to achieve the result “in the same way”. Nevertheless, Lord Neuberger’s reasoning indicates a couple of aspects that are likely to be important in future assessments:
(a) the definition of the inventive concept provided by the specification; combined with
(b) the level of understanding in the art of the mechanisms of action behind the feature(s) in question.
Lord Neuberger identified the inventive concept of Eli Lilly’s patent to be “the manufacture of a medicament which enables the pemetrexed anion to be administered with vitamin B12”[9]. Counter-ions are not even mentioned in this definition. Lord Neuberger also highlights that the counter-ions in question were well known at the priority date[10], and that the skilled person would regard investigating whether these counter-ions worked as a purely routine exercise[11]. Despite the admission that “the salt form can have a significant impact on the effectiveness of a drug in that it can modify many aspects of the drug”[12], Lord Neuberger appears to reach the conclusion that once the skilled person knows that the dipotassium version achieves the same result, then in light of this common knowledge in the art it is reasonable to consider it obvious that it works in the same way.
As such, the counter-ion was not considered to be important for the inventive concept and the action of counter-ions was well understood. On this basis, once it is known that the equivalent does achieve the same result, it is probably obvious that it works in the same way, rather than coincidentally making an effective medicine but working through a completely different mechanism of action to the chemically very similar pemetrexed disodium.
What else might work “the same way”?
Using this rationale, would an anti-folate other than pemetrexed have been found to infringe? Would a slightly altered version of vitamin B12 infringe? This was not considered in the decision, however both of these components form part of the defined inventive concept and so for this reason alone there may be a higher burden to show that it would have been obvious to the skilled person that the equivalent works the same way. This burden may be made more difficult to overcome in view of the greater complexity of the mechanism of action of these components compared to a counter ion.
It also remains to be clarified whether working in the same way refers to way that the inventive concept works or the way that the different particular feature in question works. This point was not explicitly addressed in the decision, but Lord Neuberger appears to implicitly tick both boxes by highlighting the common general knowledge in relation to counter-ions while also stating “it seems clear to me … that each of Actavis’ products would work in precisely the same way as pemetrexed disodium when included in a medicament with vitamin B12”[13]
Step (ii) – “knowing that the variant achieves substantially the same result”
It is notoriously difficult to predict the effect of a change when it comes to chemical subject matter with any certainty in the absence of experimental data. As such, that the skilled person is considered to know that “the variant achieves substantially the same result” is a very significant aspect of this new test when it comes to chemical patents. Under the previous UK infringement test it had to be obvious that the alleged infringement would achieve the same result as the claimed invention, more often than not an insurmountable hurdle.
In justifying this change, Lord Neuberger reasoned that the previous test imposed “too high a burden on the patentee”.[14] He highlighted that although “a chemist would not be able to predict the effect of a substitution [for the sodium counter-ion] without testing … salt screening is a routine exercise in determining suitability … the chemist would be reasonably confident that he would come up with a substitute for the sodium counter-ion”. Lord Neuberger therefore considered that the previous test “fails to accord a “fair protection for the patent proprietor” as required by article 1 of the protocol”. Significantly, Lord Neuberger also commented that this step should also apply “to variants which rely on, or are based on, developments which have occurred since the priority date”[15]. That is, the skilled person can be endowed with knowledge obtained after the effective date of the patent.
The effect of this significant change is to clearly bring chemical subject matter into the fold for the assessment of equivalents.
Step (iii) – “the intent” of the patentee
The change to step (ii) allows chemical subject matter to progress to step (iii) of the infringement test, however it is Lord Neuberger’s approach to applying step (iii) that is the real change that brings a broad doctrine of equivalents to the UK.
The Court of Appeal had decided that the notional addressee “would understand that the patent was clearly limited to disodium salt, and did not extend to the diacid, or the dipotassium or ditromethamine salts” simply on the basis that the specification included references to the broader anti-folate but the claims had been chosen by the patentee to be limited to pemetrexed disodium.
Lord Neuberger indicated that the Court of Appeal had erred by not departing from the language of the claim when considering step (iii)[16]. Nevertheless, he also questioned the Court of Appeal’s reasoning, arguing that the inclusion of the broad term may actually indicate that the patentee intended for a broader scope of protection[17]. In applying step (iii), Lord Neuberger indicates that “no plausible reason has been advanced why any rational patentee should want to place so narrow a limitation on his invention.”[18] As such, Lord Neuberger decided that it was “very unlikely that the notional addressee would have concluded that the patentee could have intended to exclude any pemetrexed salts other than pemetrexed disodium”.
Several factors appeared to be important in reaching this decision:
1. the breadth of the teaching in the specification:-
a. had the specification not referred to anti-folates, but only to pemetrexed disodium this would have been a “more powerful” indication the patentee intended to limit himself to pemetrexed disodium;
b. the specification teaches that there are other anti-folate drugs which have a similar effect to pemetrexed disodium;
2. the teaching in the specification in relation to the feature in question:
a. the specification contained no teaching toward the importance of the sodium cation;
3. the knowledge in the art:-
a. it was known that cations other than sodium could be successfully used with anti-folates;
b. the role of counter-ions was well understood;
4. no suitable amendments had been overlooked:-
a. there was no reference to pemetrexed salts as a class in the specification;
After reaching a provisional decision that the patentee did not intend to limit the claims to exclude the other salts, Lord Neuberger moved onto the consider whether a review of the prosecution file wrapper would alter this position.
Using the prosecution file wrapper
Eli Lilly’s patent as filed contained a broad general statement of the invention:
“a use in the manufacture of a medicament for improving the therapeutic utility of antifolate drugs by administering to the host undergoing treatment with a methylmalonic acid lowering agent such as vitamin B12”.
As would be expected for an application directed to chemical subject matter, the EPO examiner had objected to this broad claim because the generalised features covered too many combinations of compounds. The application lacked sufficient support as it only provided one example in the form of pemetrexed disodium. Eli Lilly could have filed further examples to support a broader claim scope, however, they instead tried to limit the claim by replacing “antifolate drug” with “pemetrexed”, “methylmalonic acid lowering agent” with “vitamin B12”, and by adding that the use was for inhibiting tumour growth in mammals. The EPO objected to the new claim on the ground that the patent specification as filed did not provide basis for pemetrexed, only for pemetrexed disodium. In response to this objection Eli Lilly amended “pemetrexed” to “pemetrexed disodium”. The EPO accepted these claims and the application proceeded to grant.
Lord Neuberger did not consider the intentional amendments that were made during examination to be conclusive evidence of an intent on the part of the patentee to limit the scope of the claims to pemetrexed disodium and exclude other pemetrexed compounds. It is also worth highlighting that Lord Neuberger went as far to suggest that the approach of the EPO to find that there was no basis for the term “pemetrexed salt” may have been wrong[19].
In terms of using the prosecution file wrapper generally, Lord Neuberger stated “there will be occasions when justice may fairly be said to require reference to be made to the contents of the file” but “the circumstances … must be limited”[20]. These limited circumstances may include:
(a) when the key point at issue is unclear after analysing the claims and specification (and the file history can resolve this unambiguously); or
(b) if it would be contrary to the public interest if the file history was ignored, for example if the patentee has made a relevant statement about the scope of the claims during examination of the patent application.
While Lord Neuberger’s intention may have been to only allow for rare use of the prosecution history, it is more likely that by opening the door any comments made by the applicant during prosecution that can remotely be associated with the scope of protection will be relevant during future litigation.
Summary of the decision
For the above reasons, Lord Neuberger decided that Actavis’ pemetrexed dipotassium was an equivalent and therefore was within the scope of protection provided by the claims of Eli Lilly’s patent. Direct infringement of those claims was therefore found.
Conclusions and implications
The patentee
The scope of protection for many patents may now be broader than previously thought, potentially giving the patentee another chance to obtain a desired scope of protection particularly if it could be demonstrated that the patent was unduly restricted during prosecution due to the EPO’s strict added matter practices.
This decision may also represent a slight lifting of the burden placed on patentees when preparing a patent application. The EPO’s approach toward chemical subject matter combined with the previous approach of the UK courts toward rejecting a broad “doctrine of equivalents” had placed a heavy burden on the patentee during the preparation stage of a patent application to provide comprehensive fallback positions.
Nevertheless, whilst there may be slight lifting of this burden to the extent that the doctrine of equivalents may now capture an embodiment that previously would have fallen outside of any unduly narrow granted claim, the extensive litigation required to achieve a positive outcome for Eli Lilly also serves to highlight the importance of the drafting process. In particular, the facts of this case emphasise the importance of properly addressing the broad statement of invention and the associated beneficial results, in combination with carefully selecting fall-back definitions. It also reinforces the good practice of avoiding any form of declaratory statement as to the scope of the claims during prosecution.
The third party – freedom to operate after Actavis vs Lilly
While the full impact of this decision will only become clear with the passage of time, what we do know now is that the risk levels associated with freedom to operate clearance strategies have increased.
Prior to this decision, the exact language of patent claims relating to chemical subject matter meant that an infringement opinion could be reached fairly quickly in relation to a large number of documents with a reasonably good level of certainty. A clearly omitted feature of a claim in a product for clearance usually meant that non-infringement could be concluded. The patentee, a company with reasonable resources had through its skilled technical team and presumably skilful patent attorney chosen a form of words to define its protection. It was reasonable to limit the protection afforded by the claims to the wording of the claims.
The introduction of the doctrine of equivalents into UK law changes this status quo and means it is likely that there are going to be significant gaps between the scope of protection according to the literal claims and that afforded by equivalents . Third parties should take note of the increased risk resulting from these uncertainties.
Strategies to reduce the new risk would necessitate a detailed review of the description and the costs associated with this, especially where an FTO search reveals a large number of documents, may be significant. Validity searches will be required in a larger number of cases. This will also further increase the costs for third party clearances.
To conclude, it is difficult to avoid a conclusion that this decision represents a shift toward more protection for the patentee and away from certainty for third parties.
[1] Introduced in 1973
[2] Article 1 of the Protocol on the Interpretation of Article 69 EPC.
[3] Catnic Components Ltd. v. Hill & Smith Ltd. [1982] R.P.C. 183
The Supreme Court of the United Kingdom assumed the judicial function of the House of Lords in 2009.
[4] Improver Corporation v Remington Consumer Product Limited [1990] F.S.R. 181
[5] Protocol by the Munich Act revising the EPC, dated 29 November 2000
[6] [2005] R.P.C. 9 169 KIRIN-AMGEN INC v HOECHST MARION ROUSSEL LTD HOUSE OF LORDS, Paragraphs 49 to 52
[7] Paragraph 54 of Eli Lilly v Actavis
[8] Paragraph 58 of Eli Lilly v Actavis
[9] Paragraph 61 of Eli Lilly v Actavis
[10] Paragraph 69 of Eli Lilly v Actavis, and as shown by the common general knowledge discussed at paragraph 26, points (ii) to (iv)
[11] Paragraph 69 of Eli Lilly v Actavis, and as shown by the common general knowledge discussed at paragraph 25, point (i)
[12] Paragraph 25, point v) of Eli Lilly v Actavis
[13] Paragraph 69 of Eli Lilly v Actavis
[14] Paragraph 61 of Eli Lilly v Actavis
[15] Paragraph 63 of Eli Lilly v Actavis
[16] Paragraph 71 of Eli Lilly v Actavis
[17] Paragraph 73 of Eli Lilly v Actavis
[18] Paragraph 73 of Eli Lilly v Actavis
[19] Paragraph 89 of Eli Lilly v Actavis
[20] Paragraph 87 of Eli Lilly v Actavis
