UK: Claim Interpretation Under The EPC – The UK House Of Lords Decision In Kirin-Amgem V Hoechst Marion Roussel

Last Updated: 26 October 2004
Article by Paul Cole

Kirin-Amgen Inc ("Amgen"), a Californian pharmaceutical company, is the proprietor of EP-B- 0148605 relating to the production of erythropoietin ("EPO") by recombinant DNA technology. EPO is a hormone made in the kidney that stimulates the production of red blood cells by the bone marrow. Amgen had sequenced the EPO gene and its leader sequence, which was essential to any method of making erythropoietin and which was disclosed in their patent. They then devised a method of making erythropoietin artificially for use as a drug, which was a significant advance in the treatment of anaemia, particularly when associated with kidney failure. The essence of their method as described and claimed in the patent was the introduction of an exogenous DNA sequence coding for EPO into a host cell in which it would be expressed.

The defendants were a UK subsidiary of Hoechst and were proposing to import so-called "gene-activated" erythropoietin from a company called Transkaryotic Therapies Inc (TKT). That company had devised a further way of making erythropoietin in which it is expressed in a human cell by an endogenous gene naturally present or by cells derived from such a cell. The TKT technique involved introducing the necessary control sequence upstream of the erythropoietin gene accompanied by other sequences e.g. to allow for amplification by methotrexate treatment. All this exogenous DNA has to be inserted into the human DNA at exactly the right point upstream of the EPO gene by using a phenomenon called "homologous recombination". Thus the essential difference between Amgen’s Epogen and the GA-EPO of TKT was that the former was made by an exogenous DNA sequence coding for erythropoietin which has been introduced into an host cell and the latter was made by an endogenous DNA sequence coding for EPO in a human cell into which an exogenous upstream control sequence has been inserted.

Amgen’s submission which was accepted by the High Court (Neuberger J.) was that although homologous recombination was a known phenomenon in 1983, its use to achieve "gene activation" was unknown. The method of manufacture by DNA recombinant technology referred to in the main claim of their patent was the only one known at the priority date. At the time, it was in practice equivalent to a general claim for manufacture by recombinant DNA technology. It should therefore be construed as such. Amgen said that if the claims cannot be construed in terms sufficiently general to include methods unknown at the priority date, the value of a patent would be destroyed as soon as some new technology for achieving the same result was invented. The defendants’ argument, which was accepted by the Court of Appeal, was that the man skilled in the art would not have understood the claim as sufficiently general to include gene activation. He would have understood it to be limited to the expression of an exogenous DNA sequence, which coded for EPO so that there was no infringement.

The decision of the House of Lords (Lords Hoffmann, Hope of Craighead, Roger of Earlsferry, Walker of Gestingthorpe and Brown of Eaton-under-Heywood, 21 October 2004) affirmed that of the Court of Appeal and held that there was no infringement.

One of the principal issues in the appeal was the correct application of the so-called "purposive" approach to claim construction which had been explained by Lord Diplock in Catnic Components v Hill and Smith [1982] RPC 183 and the relationship of that approach to Art. 69 EPC. Lord Hoffmann handed down the leading judgment in the House of Lords, and his opinion on this issue, which is of general importance to the profession, is summarised below:

1. Under Art. 69 EPC extent of protection conferred by a European patent is determined by the scope of the claims. Consequently the protection given by a patent cannot extend beyond the terms of the claims. That had already been decided under the common law by the House of Lords in Catnic, and when the EPC was introduced Art. 69 firmly shut the door on any doctrine that extended protection outside the claims by reference to ‘pith and marrow’ or the doctrine of equivalents. There is now no difference between the approach of the UK courts and those of courts in Germany and the Netherlands, where the claims are recognised as the decisive basis for determining the extent of protection, see Batteriekastenschnur [1989] GRUR 903, 904) and Ciba-Geigy/Oté Optics (1995) Nederlandse Jurisprudentie 39, see also the EPO Appeal Board decision in BAYER/Plant growth regulating agent [1990] EPOR 257, 261.

2. The Protocol on the Interpretation of Article 69 governs the applicable rules for construction of patent claims under Art. 69, not the construction of individual claims. The first sentence excludes the former common law rule as it had applied up to Catnic that the context provided by the description and drawings, and the background or "extrinsic evidence" could only be used to construe claims in which there was an ambiguity. Under the EPC these matters were to be available for the interpretation of all claims. The "purposive construction" required in Catnic which rejects a meaning different from what would have been understood by the person to whom the words were addressed is precisely in accordance with the Protocol. The second sentence excludes the former German approach that claims could treated simply as a point of departure and that it was legitimate to go beyond their terms to derive an inventive concept. The third sentence called for fair protection for the patentee combined with reasonable certainty for third parties, and this could only be achieved by not disappointing the reasonable expectations of either side. "What principle of interpretation would give fair protection to the patentee? Surely, a principle which would give him the full extent of the monopoly which the person skilled in the art would think he was intending to claim. And what principle would provide a reasonable degree of protection for third parties? Surely again, a principle which would not give the patentee more than the full extent of the monopoly which the person skilled in the art would think that he was intending to claim. Indeed, any other principle would also be unfair to the patentee, because it would unreasonably expose the patent to claims of invalidity on grounds of anticipation or insufficiency."

3. "The question is always what the person skilled in the art would have understood the patentee to be using the language of the claim to mean." That is an objective question depending on the words in the claim, the context of and background to those words, the identity of the person skilled in the art, and the knowledge and assumptions to be attributed to him. "There will be occasions upon which it will be obvious to the skilled man that the patentee must in some respect have departed from conventional use of language or included in his description of the invention some element which he did not mean to be essential. But one would not expect that to happen very often.... It has been suggested that in the absence of any explanation for a restriction in the extent of protection claimed, it should be presumed that there was some good reason between the patentee and the patent office. I do not think that it is sensible to have presumptions about what people must be taken to have meant but a conclusion that they have departed from conventional usage obviously needs some rational basis." See the detailed explanations that had previously been given in Mannai Investment Co Ltd v Eagle Star Life Assurance Co Ltd [1997] AC 749 and Investors Compensation Scheme Ltd v West Bromwich Building Society [1998] 1 WLR 896.

4. It is legitimate to take equivalents into account as an aid to construction because they are an important part of the background facts known to a skilled person. Taking account of equivalents in order to determine the extent of protection is specifically required by the new Art. 2 of the Protocol to Art. 69 introduced under the 2000 revisions to the EPC (not yet in force). Guidance about how to do so is given by the so-called "Protocol Questions" derived from Catnic and further explained in Improver v Remington [1990] FSR 181, 189 as follows:

"If the issue was whether a feature embodied in an alleged infringement which fell outside the primary, literal or acontextual 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 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 include the variant and the literal meaning, the latter being perhaps the most perfect, best-known or striking example of the class."

However, in those cases where the Protocol questions are helpful, instead of asking whether the variant works in the same way, it may now be better to follow the German courts and ask whether the variant solves the problem underlying the invention by means having the same technical effect, see the "quintet" of cases before the Bundesgerichtshof, for example, Kunstoffrohrteil [2002] GRUR 511 and Schneidemesser 1 [2003] ENPR 12 309 (which concerned questions whether figures or measurements in a claim allow some degree of approximation) and see also a paper by Dr Peter Meier-Beck (currently a judge of the 10th Senate) to be published in the International Review of Intellectual Property and Competition Law (IIC).

5. The Protocol questions may be helpful for questions as in Catnic and in the "quintet" of German cases whether figures and measurements are used in a strict conventional sense or as approximations as in Catnic, or in situations where the decision to be made is between strict compliance with the conventional meaning of a word or phrase or a looser interpretation. However, they should be treated as guidelines more useful in some cases than in others and should not be treated as legal rules. "No doubt there will be patent lawyers who are dismayed at the notion that the Protocol questions do not provide an answer in every case. They may feel cast adrift on a sea of interpretative uncertainty. But that is the fate of all who have to understand what people mean by using language. The Protocol questions are useful in many cases, but they are not a substitute for trying to understand what the person skilled in the art would have understood the patentee to mean by the language of the claims."

6. In particular, the Protocol questions are not helpful where it is first necessary to construe the claim and decide what the person skilled in the art would understand the was the level of generality of the invention, i.e. what the invention really is, the Protocol questions answering themselves when that issue had been decided. In the present case, that question was whether the skilled person would understand the invention to be (a) the discovery of the sequence of the erythropoietin gene and its associated information so that any method of making erythropoietin using exogenous or endogenous DNA would be covered, or (b) a specific way of making erythropoietin using the sequence information, so that a different way of making erythropoietin using the same information was not covered. The second answer was to be preferred in this particular case.

7. The Protocol questions may also be unhelpful in the case of new technology when the question was whether the claims could properly be construed in a way that was sufficiently general to cover the new technology or whether they were restricted to existing technology because of doubts about sufficiency rather than lack of forethought about future developments. "There is no difficulty in principle about construing general terms to include embodiments which were unknown at the time the document was written. One frequently does that in construing legislation, for example, by construing "carriage" in a 19th century statute to include a motor car. In such cases it is particularly important not to be too literal. It may be clear from the language, context and background that the patentee intended to refer in general terms to, for example, every way of achieving a certain result, even though he has used language which is in some respects inappropriate in relation to a new way of achieving that result: compare Regina (Quintavalle) v Secretary of State for Health [2003] 2 AC 687. In the present case, however, I agree with the Court of Appeal (and with the judge, before he came to apply the Protocol questions) that the man skilled in the art would not have understood the claim as sufficiently general to include gene activation. He would have understood it to be limited to the expression of an exogenous DNA sequence which coded for EPO."

In supporting his conclusions, Lord Hoffmann explained that there were two ways in which the obstruction that an over-literal approach to claim interpretation created for fair protection to the patentee. One possibility which had been followed by the courts in the US was to maintain the literal approach but to supplement it by a doctrine of equivalents, see Graver Tank v Linde 339 US 605, 607 and Royal Typewriter v Remington (CA 2nd Conn) 168 F2nd 691, 692. However, once the monopoly had been allowed to escape from the terms of the claims, it was difficult to know where the limits should be drawn, and US litigation showed that patent litigants were paying dearly for results that were no more just and predictable than could be achieved by simply reading the claims, see Warner-Jenkinson v Hilton Davis 520 US 17, 28-29 (1997) and Festo v Shoketsu Kinzoku 324 F3rd 558 (CAFC, 2000) and 28 May 2002 (US Supreme Court). The alternative solution of abandoning the literal approach, as the House of Lords had done in Catnic, was preferable because it gave effect to what a person skilled in the art would have understood the patentee to be claiming.


If the "one compulsory question" (Lord Walker) under Art. 69 EPC is what the skilled reader would have understood the claim to mean, then the almost invariable answer is that a UK court will not go beyond the natural meaning of the words in the claim, interpreted in context perhaps, but not stretched to some broader generality that can be discerned with hindsight from the disclosure but is not found in any claim. We may find instances where the construction of a claim may in the opinion of some be too narrow or may be incorrect, but we do not find anything as egregious as the rejected argument in Mannai (supra) that a notice under a lease was ineffective on the mere technicality that the date of expiry quoted in the notice letter was one day earlier than permitted under the termination clause.

At least by the 1960’s it was a misrepresentation to say that the reason why the UK courts almost never applied the doctrine of equivalents was because of an anachronistic devotion to literalism. It is reasonable to assume that the UK cases that created concern amongst continental European practitioners and prompted drafting of the Protocol were Van der Lely v Bamfords [1963] RPC 61 and Rodi & Wienenberger v Showell [1969] RPC 367. In Van der Lely, the claimed inventive concept was converting a side delivery rake to a swathe turner by moving a "hindmost" group of rake wheels. The decision of the House of Lords that only movement of that group of wheels was covered was contextual because only that group had ever been disclosed as movable. The House of Lords was satisfied that the patentee had never thought of the alternative of moving the foremost group of wheels, and was not prepared to broaden the claimed inventive concept with retrospective effect to cover an undisclosed embodiment. It is submitted that it would be equally difficult today to persuade a UK court that a reasonable engineer would have understood "hindmost" to be a figurative expression also covering movement of the foremost group, and that many engineers would regard this as an outrageous extension of the originally claimed subject matter. Similarly the reason why Rodi & Wienenberger could not enforce their patent was not an acontextual claim interpretation, but belief that what the patentees had invented was limited to the flexible inexpensively assembled bracelet structure defined in some detail in the main claim, so that it was not legitimate to omit the detail with retrospective effect in order to cover the defendant’s differently constructed embodiment. In both cases, the temptation to broaden the inventive concept came not from the patentee’s disclosure or his contemporary foresight definition of his invention, but from hindsight knowledge of the defendant’s redesign. Although these decisions created surprise in some European countries given their different pre-EPC judicial approach, the recent case law quoted by Lord Hoffmann shows that such judges would now fully appreciate their reasoning.

Probably Kirin-Amgen is the last word about claim interpretation from the House of Lords for a generation, and its full implications will take as long to become apparent than those of Catnic. Expert evidence concerning the "matrix of fact" referred to by Mummery J. in Glaverbel v British Coal [1993] RPC 90 and concerning the understanding of the claims by a skilled person may become even more significant than at present. Where the relevant words in a claim are ordinary English without specialised meaning, the courts have tended to doubt the need for evidence as to construction, and the present decision may make them more receptive to such evidence. However the outcome of Kirin-Amgen may prove to be no more than placing the logic under which claims are interpreted on a sounder foundation, and shifting the battleground from a place called "equivalents" to a place called "construction", the protagonists and the dispute being otherwise unaffected as is the likely result.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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