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Published: Fri, 02 Feb 2018

Patent Infringement Protection | Free Copyright Law Essay

International and Comparative Patent Law: American Home Products v Novartis (2001) RPC 159 elevates the protocol questions to the test for patent infringement. Explain on the basis of the facts of this case how the United Kingdom meets in this way its obligations under the protocol to article 69 of the European Patent Convention (as amended in 2000).

Under the patent law of the United Kingdom (UK), the protection afforded by a patent claim is defined by statute subject to the interpretation by the courts. Interpretation or construction of claims is a primordial issue in almost all patent systems. In most alleged infringement of patent actions, the task is first to establish that the patent is valid and that the act alleged infringes a valid patent. Rarely, an allegedly infringing invention is an exact copy of a valid patent such that a patent holder would be forced to argue that despite the differences, an alleged infringement activity is still witin the scope of the monopoly. The defendant, on the other hand, will most usually deny the infringement act by establishing that the product or variant is not covered by the patent claims or in the alternative, that the patent is obvious or anticipated. A patent is a monopoly granted by the UK in exchange for disclosing an invention or process to the general public. Such disclosure of invention or process are made in a document called “the specification”. The specification, which also delineates the monopoly, under S.14(2) of the Patents Act 1977 is required to be performed by a person skilled in the art and prescribing at least one claim with a description of the matter to be protected. Section 125(1) of the Patents Act 1977 (counterpart of Article 69, European Patent Convention or EPC) provides that “for the purposes of this Act, an invention for a patent … shall, unless the context otherwise requires, be taken to be that specified in a claim of the specification … as interpreted by the description and any drawings contained in that specification …”. Furthermore, Section 125(3) requires that the claim be interpreted in accordance with the Protocol on interpretation of Article 69, EPC (hereinafter the “Protocol”). The Protocol provides as follows:

Article 1

General principles

Article 69 should not be interpreted as meaning that the extent of the protection conferred by a European patent is to be understood as that defined by the strict, literal meaning of the wording used in the claims, the description and drawings being employed only for the purpose of resolving an ambiguity found in the claims. Nor should it be taken to mean that the claims serve only as a guideline and that the actual protection conferred may extend to what, from a consideration of the description and drawings by a person skilled in the art, the patent proprietor has contemplated. On the contrary, it is to be interpreted as defining a position between these extremes which combines a fair protection for the patent proprietor with a reasonable degree of legal certainty for third parties.

Article 2


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.”

The Protocol originated as an attempt to reconcile the previously divergent approaches to claim interpretation in Europe. In contrast to the common law “fence post” approach in which patent protection was closely tied to the wording of the claims, civil law countries such as Germany adopted a “sign post” approach where claims were seen as defining the general inventive concept or “Kerntheorie” of an invention. Under this “sign post” approach a patent would be infringed if the identified inventive concept were utilised even if the infringement did not fall literally within the wording of the claims. With the adoption of the Protocol, the German courts now accept that the claims are no longer merely a pointer towards a claimed inventive concept, and that the claims now define the boundaries of a monopoly. The English courts have also accepted that the strict literalism of the past and the limited application of the doctrine of the pith and marrow have been superseded by a “purposive” approach to claim construction, where the scope of protection extends beyond its literal meaning to encompass variants of a claimed invention. Together Article 69 EPC and its Protocol form the basis of modern English claim interpretation. The wording of Art. 69 EPC as reflected in S.125 mentioned above clearly states that the extent of protection conferred by a patent is that defined by the claims as interpreted in light of the specification and drawings. The Protocol then goes on to state that this scope of protection extends beyond the literal meaning of the wording of the claims themselves to include a penumbra of protection which combines a fair degree of protection while being limited to the extent that the claims themselves provide third parties with a reasonable degree of certainty as to the scope of protection. Just as under the common law, therefore, the starting point for determining the scope of a patent remains the wording of the claims. From the Protocol, it can be taken that anything which falls within the literal wording of the claims as properly interpreted necessarily falls within the scope of a patent, as the Protocol identifies the literal interpretation of the claims as being less than the minimum extent of protection. Article 69 EPC also provides guidance as to how the wording of the claims is to be interpreted. It states that the claims are to be interpreted in the light of “the description and any drawings contained in [the accompanying] specification”. Together with Article 69 EPC, therefore, it identifies the claims, description and drawings of a specification as the primary arbiters of determining claim scope. However, this is not to exclude all other evidence as to the meaning of the claims. In addition to the materials to be used to interpret a claim, it is also necessary to identify from whose viewpoint the claims are to be read. In the UK, it is well settled that “patent specifications are intended to be read by persons skilled in the relevant art, but their construction is for the Court. Thus the Court must adopt the mantle of the notional skilled addressee, and determine … what the notional skilled addressee would understand to be the ambit of the claim”. The role of expert evidence in the UK patent system is therefore to enable a judge to understand the description, claims and drawings as the man skilled in the art would understand them.

A monopoly granted by a patent is limited by the language of its patent claims although an extended meaning may be given to such language if that is how it would be understood by the person skilled in the art. Be that as it may, it should not depart from the language pursuant to the Protocol. In applying the Protocol, judges and courts in the UK have recognised that the Protocol favours neither a strict literal interpretation nor a liberal interpretation by merely using the claims as a guideline. Hence, a correct approach as mandated by the Protocol is to achieve a balance of position between a strict literal approach and liberal interpretation without disregarding the language of the claims. Under this approach, the claim will be interpreted in the eyes of the skilled addressee while the role of the judges or the courts is to ascertain the meaning the terms of the claim that were intended to be conveyed. In aid of interpretation of patent claims, the Court of Appeal places much reliance on the method used by the House of Lords in the case of Catnic v Hill & Smith [1982] RPC 183 where the Court emphasised that in patent specifications, the patent holder is considered to have addressed those skilled in the art and to have informed them of what the patentee claims to be the important feature of his product or process. To determine what the important feature is, the specification is to be given “purposive” construction, instead of a purely literal interpretation. The court will ask whether a skilled addressee understands, what the patentee intends as the essential feature of his invention. There should be a strict compliance of a particular descriptive term in a patent claim such that a variant would fall outside of the claimed patent, even if the same does not have any effect on how the invention works. The Court of Appeal stated that there is no issue as to whether a variant would effect materially how the invention works. Such issue would not also crop up unless and until at the date of publication of the specification. In case that it was not obvious in view of the existing knowledge, the audience may assume that the patent holder has intended a limit to the monopoly. The Catnic approach was subsequently reformulated into three separate questions by the Court in the case of Improver v Remington [1990] FSR 181.

While the Improver case was decided under the regime of the UK Patents Act 1949 which is before the effectivity of the Patents Act 1977 and before the incorporation of the Protocol, the so-called three (3) “Improver questions” have been re-adopted by the Court to aid in the application of the Protocol. In the case of Wheatley (Davina) v Drillsafe Ltd [2001] RPC 7, the so-called three (3) “Improver questions” has since then been called the “Protocol questions”. It is to be observed that there is no “doctrine of equivalents” in the UK intellectual property law. Ultimately, as stated in Improver, “the end the question is always whether the alleged infringement is covered by the language of the claim,” that is, the scope of patent protection should be rooted on the terms of the claims itself. In the case of Anchor Building Products v Redland Roof Tiles [1990] RPC 283, the Court formulated the issue to be whether the claimed infringement is one which the skilled man in the art could regard the act as being “within the ambit of the language” of the patent claim. These then “Improver” or the now “Protocol” questions are formulated in this way:

“1. Does the variant have a material effect on the way the invention works? If yes, the variant is outside the claim. If no –

2. Would this (i.e. the fact that the variant has no material effect) have been obvious at the date of publication of the patent to a person 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 claims. If no, the variant infringes.”

Questions 1 and 2 are clearly questions of fact. However, it must be observed that in Question 2, the issue is not whether the variant is an obvious alternative to the device referred by any literal interpretation but it presupposes that the skilled man in the art is informed of the new invention and any variant and whether the latter would work in the same way as the invention. The “obviousness” test applied by the Court here is beyond the test used in order to evaluate inventiveness. The Court has the tendency to require a clear and apparent test by mere looking at the claimed variant that the latter works similarly as the new invention. In fact, it is insufficient, as will be discussed more fully below, that the variant when tested is highly likely to work: American Home Products v Novartis Pharmaceuticals UK Ltd [2002] RPC 8, and that all a skilled man in the art may know is what the variant is. Such skilled man cannot be informed on how the variant works, thus limiting the rules in relation to biochemical processes and inventions. Seldom that it can be immediately apparent by merely looking at a biochemical formula that it will work in the same way as the invention. What is the relevant date to evaluate Question 2. In Catnic, the House of Lords reckoned it as the date of publication. Question 3 is a matter of construction and clearly the essential question. What will the skilled reader in the art understand as the patent holder’s intention from the language of the claim used? While the Court adopts the view of the skilled person in the art, it has historically arrogated to itself the task of constructing the language of the patent claim.

As stated above, the first Protocol question is a question of fact that can only be answered with recourse to the patent specification and claims. When addressing the first Protocol question, the wording of a claim serves two purposes. First, the literal wording of the claim provides the definition against which the alleged infringement is judged in order to determine whether the alleged infringement is indeed a variant. Secondly, the question of whether the working of a variant differs from the claimed invention and whether this has a material effect is then answered at the level of abstraction of the claim itself. It is only once the invention as described in the patent has been identified that whether a variant has a material effect on the way the invention works can be determined. The focus then is not on whether the variant differs from the claim but rather whether the differences are such as to affect the working of the identified invention. If the differences between a claim and a variant cause the variant to operate in a fundamentally different way from the identified invention, the variant will not infringe. Conversely, even if a variant works in a different way or has advantages of its own, unless these differences affect the working of the identified invention the variant may still be considered to be within the scope of the claims.

The second Protocol question is addressed after it has been determined that a variant does not affect the way the invention works and is therefore considered based on the assumption that the variant has no material effect. As in the case of the first Protocol question, the second Protocol question is a question of fact that is answered against the background provided by the patent. The purpose of the second Protocol question is to limit the scope of patent protection to cover only variants of the invention where a skilled man, at the date of publication, would have considered it obvious that the variant had no material effect on the working of an invention. The question supposes that the skilled man at the date of publication is told of both the invention and the variant and asks whether the variant would be one which would have suggested itself as an obvious alternative. By asking the question in the light of both the invention and the alleged infringement, the court avoids addressing whether the development of the variant was inventive. Instead, the court limits its investigation to whether or not the skilled man would immediately realise that adopting the proposed variant would be immaterial to the functioning of the claimed invention.

It is with the third Protocol question that the court finally focuses on the wording of a claim. The first two Protocol questions establish the factual background against which the third question is asked, as they identify the maximum scope of protection that a claim might enjoy covering all possible variants, which make no material difference to an invention and where this would have been obvious at the time of publication. The third Protocol question examines the wording of a claim to establish whether the patentee for some reason has limited this potentially expansive scope to the primary literal meaning of the claim. Importantly, this third Protocol question ensures that, although the court may stretch the literal meaning of a claim, the wording of the claim acts to limit the scope of protection.

In applying this final test, the third Protocol question is not applied with an eye to infringement. This is because “[t]aken out of its original context there is always a danger in the nutshell question: there is never a plausible reason why the patentee (assuming his claim is valid) would want to exclude a competitor’s product”. Rather, the court will consider the merits of any argument which might indicate that the scope of protection should be limited. Thus, for example, analysis of the claims might cause the court to restrict the scope of a claim to exclude variants which do not solve the problem addressed by the patent. Another plausible reason for restricting the scope of protection could be to avoid rendering a patent void for obviousness. As there is no obligation for a patentee to disclose prior art to the British Patent Office, frequently there will be no indication as to why a claim is worded in a particular way. In such circumstances, the court will seek to balance plausible reasons as to why a broader construction should be placed on a claim against the possibility that some element in the claims has “some purpose buried in the prior art and even if this is not discernible, [the possibility that] the patentee may have had some reason of his own for introducing it”.

While the Protocol questions have been used by the Court merely as an “aid” in the interpretation of the claim of infringement, the Court have treated such questions as decisive. Thus, in the case of American Home Products Corp v Novartis Pharmaceuticals UK Ltd [2002] RPC 8 (“Novartis”), the Court has elevated the Protocol Questions as the decisive test for patent infringement. In the Novartis decision, the UK has clearly met its obligations under the Protocol where the face of a patent also referred to an additional technical information, the Court declined to refer to such additional technical information to determine the scope of the claims.

In Novartis, Claim 1 of the subject patent stated as follows: “Use of rapamycin for the preparation of a medicament for inhibiting organ or tissue transplant rejection in a mammal in need thereof” Rapamycin was known as an antifungal antibiotic and the claims of the patent were thus in “second use” form. The alleged infringement was a derivative of rapamycin in which the hydroxyl group at position 40 had been O-alkylated with a 2-hydroxyethyl group. This derivative was referred to as SDZ RAD. The defendants contended that derivatives of rapamycin did not fall within the ambit of the claims and that, if they did, the patent was invalid as it was insufficient in that there was no disclosure in the specification of how to make or select derivatives of rapamycin to prepare a medicament “suitable for inhibiting organ or tissue transplant rejection in a mammal” as required by Claim 1. The judge heard the issues of construction and sufficiency was a preliminary issue. The judge construed the word “rapamycin” in Claim 1 as including derivatives with the result that the functional words in the claim limited it to rapamycin and its derivatives which were suitable for preparation of a medicament which was suitable for treating organ transplant rejection. The judge rejected the insufficiency attack and found in favour of the patentee. The defendants appealed. The patentee contended that Claim 1 should be read as meaning “rapamycin itself and derivatives thereof which exhibit the same type of inhibition to organ rejection as rapamycin and which are suitable for the preparation of a medicament for inhibiting organ or tissue transplant rejection in a mammal”. In relation to infringement, the patentee contended that as the claim only covered variants which were suitable for producing a medicament which had to be suitable for inhibiting rejection, the variants could not have a material effect on the way the invention worked and further that the functional limitation would be answered in the affirmative as it would be obvious that the variant would work in the same way. The patentee argued that SDZ RAD infringed Claim 1 even if, on its true construction, it was limited to the use of rapamycin itself. It contended that Claim 1 was a process claim and that the defendants – (1) had manufactured SDZ RAD using rapamycin as the starting material; (2) had imported a product (SDZ RAD) obtained by means of the process of Claim 1; and (3) had used rapamycin for the preparation of a medicament which was suitable for inhibiting transplant rejection. The Court held that there was no infringement based on its construction of the claim as excluding derivatives of rapamycin and, on such construction, rejected the challenge on insufficiency.

The Court stated that throughout the specification the word “rapamycin” was used to denote the molecule rapamycin. The only references to derivatives were in the title and in a passage which drew a distinction between rapamycin and derivatives. The specification did not identify a single derivative which had been shown to work. Applying the “Protocol questions”, the invention was the discovery of a second medical use for rapamycin and the variation was the class of compounds called derivatives of rapamycin with the actual variant in issue being SDZ RAD. The Court held that the patent holder’s approach to infringement was fallacious and would always result in the first two Protocol Questions being answered in its favour if a claim was limited to variants which would work and obviously work. It was held that there was no basis in the specification to enable the skilled person to decide whether a particular derivative had rapamycin-like effect other than the requirement of the functional part of the claim. The variant was not, as the patentee contended, a derivative which had rapamycin-like effect or was a derivative which complied with the functional limitation in the claim. The variant was either all derivatives of rapamycin or the particular derivative SDZ-RAD. Although the judge, the Court noted, had not made a specific finding as to the equivalence of SDZ-RAD to rapamycin, there was evidence that the use of SDZ-RAD would not materially affect the way the invention worked. Thus, the answer to the first Protocol Question was assumed to be in favour of the patentee. It was fair to the patentee to include within the claim immaterial variants and to exclude material variants: hence, the first Protocol Question. However, third parties had to be taken into account and the second Protocol Question was designed for that purpose because it excluded variants unless third parties should have realised they were immaterial. For there to be reasonable certainty, those were variants which were obviously or clearly immaterial.

In Novartis, Aldous L.J. discussed the issue of the level of knowledge should be imputed to the hypothetical skilled reader to answer the second Question of whether it would have been obvious that the (later and possibly inventive) variant has no material effect on the way the invention works. Aldous noted that it is not enough that the variant might be a good candidate to try, or that the variant is one of a number of possibilities that might require research to determine whether it would work. He suggested that to be fair to the public, the person to whom the specification was addressed should not have built the device and test it to determine whether it is equivalent. Novartis takes the Protocol analysis further in certain instances when at the publication date of the patent, the patentee could not have possibly envisioned the feature of the variant in question. Novartis tells us that the hypothetical test is that the skilled reader is considered to be presented with the construction of that variant, and is asked whether from its construction alone, he would have known that the variant did not have a material effect on the way the invention works, and whether this would have been obvious. If the answers are “no” and “yes”, the factual enquiry is concluded and the third Protocol Question is considered. The Court moved the date at which the hypothetical skilled reader has to consider the second Question. The House of Lords in Catnic said that the critical date is the date of the publication of the specification. As recently as March 2002 the Court of Appeal was continuing to quote that as the critical date, but in view of the 1996 House of Lords ruling in Biogen v Medeva, the Court in Novartis considered evidence from the application date to determine sufficiency of disclosure and used that evidence to address the second Protocol Question. The Court looked at the evidence from the filing date (1984) to answer the second Protocol question and justified the approach: “To seek to monopolise use of the sequence when not isolated by inserting a construct into a human cell would provide a monopoly not properly supported by the description in the specification”. Biogen then modified the test in Catnic. The second question is to be judged at the filing date of the application (or the priority date if this is claimed and is relied on) and not the publication date. The variant cannot fall within the scope of the claim if such scope would not have been supported by the description at the filing date.

In Novartis, the judge found that at the date of the patent there was a strong probability that some derivatives of rapamycin would work but it was impossible to predict with certainty whether any particular one would. It might be that SDZ-RAD was a good candidate to try but it was not obvious that it would work as an immunosuppressant. The same was true in relation to other derivatives. Accordingly, the answer to the second Protocol Question was “no”. The answer to the third Protocol Question was “yes”. Throughout the specification, the word “rapamycin” was used to designate the molecule rapamycin and derivatives were referred to as such. It was not to be expected that a different nomenclature would be used in the claims. Furthermore, a claim to rapamycin and rapamycin derivatives or rapamycin-like derivatives would not have been allowed by the European Patent Office as it lacked support and would have been speculative. There was a difference between a specification which required the skilled person to use his skill and application to perform the invention and one which required him to go to the expense and labour of trying to escertain whether some product had the required properties. When carrying out the former, the skilled person was trying to perform the invention, whereas the latter required him to go further and to carry out research to ascertain how the invention was to be performed. If the latter was required the specification would appear to be insufficient. According to the Court, the duty of the patent holder was to provide a description which would enable the skilled person to perform the invention across the breadth of the claim and not to supply a starting point for a research programme. If the claim was to be construed so as to include derivatives of rapamycin, an enabling description of such derivatives was needed so that the products of the claim could be ascertained. Once it was appreciated that a claim which encompassed derivatives had to be sufficient across its breadth, the extent of the research task to find out which derivatives would work became apparent. The number of derivatives was vast and the task of ascertaining which would satisfy the functional part of the claim would also be vast and correspondingly burdensome. If Claim 1 is to be construed so as to cover derivatives of rapamycin, then it would be invalidated for insufficiency. The Court noted that Claim 1 was a Swiss-type claim and the specification made it clear that the medicament which provided the inhibition was rapamycin. The word “medicament” should not be construed so as to mean any product whether or not it contained rapamycin as that would render the claim invalid. As a consequence, SDZ RAD was not a medicament within the meaning of Claim 1 and the use of rapamycin to produce it did not amount to infringement. On the basis of the foregoing discussion, therefore, the Court in American Home Products Corp v Novartis Pharmaceuticals UK Ltd [2002] RPC 8 has clearly elevated the Protocol questions as the decisive test for patent infringement and thus, enabling the UK to meet its obligations under Article 69 EPC and its Protocol.


  • 3M v Plastus Kreative [1997] R.P.C. 737
  • American Home Products v Novartis Pharmaceuticals UK Ltd [2002] RPC 8
  • Anchor Building Products v Redland Roof Tiles [1990] RPC 283
  • Biogen Inc. v. Medeva Plc [1997] R.P.C. 1.
  • Catnic v Hill & Smith [1982] RPC 183
  • G. Aharonian (trans.), The Concept of Technical Invention, Deutsches Patent und
  • Markenamt, (Document no. EUROTAB 2/2002e, March 4, 2002)
  • Improver v Remington [1990] FSR 181
  • Kastner v Rizla Ltd (No.1) [1995] R.P.C. 585, CA
  • Lubrizol v Esso [1998] R.P.C. 727
  • Mentor Corporation v. Hollister Inc. [1993] R.P.C. 7.
  • Merck & Co Inc v Generics (UK) Ltd. [2003] EWHC 2842 (Patent)
  • Optical Coating Laboratory v Pilkington [1995] R.P.C. 145
  • Re Formstein [1991] R.P.C. 597
  • STEP v Emson [1993] R.P.C. 513
  • Wheatley (Davina) v. Drillsafe Ltd, [2001] R.P.C. 7, CA.

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