The defendants argued that their pliers (illustrated below) did not have a pair of rigid elongated members crossing each other. First, one of the crossing jaw-handle members was made of two parts (parts A and B in our figure), so it was neither rigid nor a member. Second, there was not a pair of members, but three members A, B and C. The Patents County Court was not convinced by these arguments and the Court of Appeal agreed, saying that there was nothing in the claim that required the handle member to be made of one part, and saying that each member must have sufficient rigidity to be part of a plier-like tool to ensure that the manual pressure on the handle end causes the jaws to grip the workpiece.

The defendants also argued that their pliers had no “slidable and pivotable fastening means connecting the members between their neck portions”, in part because the pin that holds part B in the slot of part C did not pivot. Upon contact with the workpiece, the pin seats in a semi-circular recess in the slot thereby halting sliding action and enabling the members to pivot, but unlike the pawl of the preferred embodiment in the specification, the defendant’s pin was rigidly fixed to part B.

The Patents County Court believed that it would be a misuse of language to encompass a means which was not itself pivotable. The Court of Appeal over-ruled on this point and said that the phrase “slidable and pivotable fastening means” referred to a composite structure which could be made up of a number of parts, and the means itself need not be pivotable. There was nothing in claim 1 that required the pin to pivot. (Indeed dependent claim 2 made reference to the fastening means having a fastener stationarily secured to the second member, so the repercussive effect of this on claim 1 was that the fastener - i.e. pin - need not pivot.)

The Court of Appeal did not need to mechanistically apply the Protocol Questions. The Court barely considered the defendants’ pliers to be a variant on the literal wording of the claim and said that to construe the claim to exclude the defendants’ pliers would not provide fair protection for the patentee. The Court found that the defendants’ pliers infringed. Critical to that ruling was that those pliers, like the patentee’s pliers but unlike the prior art, had a biasing spring action that urged the jaws to a fully open position when released, so that in one-handed closing operation it could adjust to any size of workpiece and grip the workpiece.

Comment on Warheit

The Warheit decision shows the great value of the word “means” in a claim. In Warheit, it seems that the words “pivotable fastening means” provided the necessary flexibility (as opposed to perhaps “pivoting fastener” or “pivot and fastener”), so that the term need not be ignored, but could still be construed to encompass a composite construction that did not itself pivot.

Indeed, the term “means” is so flexible that Warheit is not really a purposive construction case at all. Warheit illustrates a preference for the Court to dispose of the matter on the basis of the Protocol if that can be done without resorting to the more indirect route of using the three Protocol Questions.

What if the variant is itself an invention?

The second Protocol Question asks “Would it have been obvious at the date of publication that the variant had no material effect upon the way the invention works?” This question frequently poses difficulties, because it is often the case that the infringing article or process is itself in some way inventive over the claimed invention, yet that is no defence to infringement if it falls within the ambit of the claim. The question poses a hypothesis in which the later variant is viewed through the eyes of the skilled person at an earlier date, before it was invented. In that hypothesis, how much do we tell the skilled man about this new invention to allow him to consider whether it is obvious that it would have no material effect on the earlier invention? Do we tell him how it works? Do we tell him that it does in fact work? Is it enough that it might work? Or do we leave him to figure all that out from his knowledge as it stood at that time? And in answering the third Protocol Question, is the draftsman forgiven for drafting a claim that excludes the unexpected?

Here we look at how the question was addressed in Kirin-Amgen v Hoechst (unreported, on appeal from Kirin-Amgen v Roche [2002] RPC 1) and we look at a recent Patent Office decision that foreshadowed the Court of Appeal ruling.

Kirin-Amgen v Hoechst and TKT

Kirin-Amgen (referred herein as “Amgen”) had invented a method of production of the protein erythropoietin (EPO) by genetic engineering techniques. EPO is a very important hormone that stimulates the production of red blood cells in humans and is consequently useful in the treatment of anaemia, especially following kidney failure. The EPO produced by Amgen is reported to generate over $1 billion per year in sales worldwide. The UK Court of Appeal action was just one of many actions by Amgen against parties around the world manufacturing EPO using genetic engineering techniques.

Tumour cell that receives a targeting construct is not a “host” cell

The method described by Amgen in its patent involves isolating and cloning an exogenous DNA sequence encoding EPO (i.e. DNA manufactured outside the host cell) and transforming or transfecting a host cell with this DNA. Amgen described and claimed a "principle of general application" ([2002] EWCA Civ. 1096, para. 78) in which the necessary DNA sequence coding for EPO and a suitable host cell (a Chinese hamster ovary cell) were described, to enable the manufacture of EPO on an industrial scale. By contrast, the technique used by TKT involved a wholly new and different technique devised later which could not have been within the contemplation of the inventor at the time the patent application was written.

TKT used technology that did not involve isolation or encoding of an EPO-encoding sequence. TKT started with an endogenous encoding sequence already present in human cells. TKT’s process involved a viral promoter to “switch on” the otherwise dormant EPO coding gene in human cells. The process involved inserting several other gene elements (a “targeting construct”) including an amplifier gene (as used by Amgen), a human growth hormone (hGH) peptide and a marker gene. These were inserted into human tumour cells. The marker gene allowed TKT to separate out the cells that had successfully taken up the targeting construct, and these were then screened for EPO (using the same screening process as used by Amgen).

The Court of Appeal held that claim 1 (see below) was not infringed on a literal interpretation because TKT’s human tumour cell was not a “host cell” in the sense of the claim, because it did not introduce into it isolated (i.e. exogenous) EPO-encoding genetic material. The EPO-encoding genetic material was already present in the cell and the exogenous material introduced was the targeting construct. Accordingly the Court proceeded to consider the requirement of the Protocol on Interpretation and the three Protocol Questions.

First Protocol Question

The Court of Appeal pointed out that the answer to the first Question depends on the level of generality used to describe the way the invention works. The wider the description, the easier it is to fit the variant into the description. The right approach is to describe the working of the invention at the level of generality with which it is described in the claim of the patent.

In this case the Patents Court had not actually selected a word or phrase (such as “host”) to which the Protocol Questions should be applied. The “variant” was the different process used by TKT. The judge (Mr Justice Neuberger) concluded that the essence of the invention was the sequence which enabled products of EPO using biological materials. In answer to the first Protocol Question, he found that the only significant variant was the use of TKT’s technology (which did not exist in 1984) to use the same EPO coding sequence to express the same EPO artificially in a eukaryotic cell using an exogenous promotor (Amgen’s coding sequence was exogenous). The Court of Appeal overturned the Patents Court on this application of the first Protocol Question.

The Court of Appeal pointed out that the gene sequence was not claimed as the invention (because a claim to the sequence per se would not be patentable).

The claim was to a DNA sequence which had been made suitable for use in a host cell to produce EPO. In effect the claim was to an exogenous DNA sequence suitable for expressing EPO when introduced to a host cell. By contrast, TKT’s variant was “very different”. The DNA sequence was endogenous, i.e. already in the cell. It was not suitable for expressing EPO until after introduction of the [exogenous] gene-activating construct. The Court of Appeal concluded that the answer to the first Protocol Question was “yes”, the variant did have a material effect on the way the invention worked.

Second Protocol Question

Although a positive answer to the first Protocol Question was sufficient to find no infringement, the Court of Appeal went on to consider the second Question. The Court ruled that the judge had started from too broad a definition of the way that the invention worked, and from such a broad definition, the differences between the invention and the variant were excluded from consideration. The Court said that the skilled person needed to be (hypothetically) told of the construction of the alleged infringement and then he had to decide whether it obviously worked in the same way. The second Question is designed to secure a reasonable degree of certainty for third parties. The Court of Appeal said that, if it were supposed that the answer to the first Question was “no”, i.e. that the variant had no material effect on the way the invention worked, the evidence was that in 1984 the skilled person would not have expected the variant to work at all. So it could not have been obvious that it would work in the same way and the answer to the second Question must be “no”.

Comment on Amgen

In this particular situation, where the skilled person could not have known at the publication date that the variant would work, we have the unusual possibility that the answer to the first Question might be “no” (i.e. the variant has no material effect on the way the invention works) while the answer to the second Question is also “no” (it would not have been obvious that the variant had no material effect on the way the invention works).

We can see from our table how unusual this outcome is. The only case producing this outcome is Union Carbide v. B P when considering BP's Mark 3 polymerisation process. In that process, instead of introducing a two-phase liquid/gas mixture into the fluidising bed, BP reintroduced "atomised liquid" directly. The liquid was not entrained in any gas, so no two-phase mixture was formed until it had been introduced into the bed. While “prepared to assume” that direct injection of liquid would not have a material effect on the way the invention worked, the court (Aldous L.J. giving the judgment) saw no reason to believe that this would have been obvious to the skilled man.

The question of how much information about the infringement we should impute to the skilled reader arose in the recent Patent Office case Owen Mumford v Novo Nordisk O/261/02 (decided before the Court of Appeal’s ruling in Amgen). In that case the Hearing Officer also considered the need for the second Question.

Owen Mumford v Novo Nordisk

The case arose on an application under Section 71 for a declaration of non-infringement. The patent was for a pen syringe of the sort commonly used by diabetics to administer insulin.

The Hearing Officer noted that Neuberger J concluded in Amgen that the skilled man should know that the variant works, but he did not construe Amgen as meaning that the skilled man must always be told this. The parties agreed that nothing would be gained by trying to apply the Patents Court ruling of Amgen to the dispute in question, as the latter was a much slower moving field of technology. The Hearing Officer pointed out that the second Protocol Question does not ask whether the variant would work, but neither is it correct to assume in the hypothetical that the skilled person should be provided with a working example, as that would “tip the balance rather too heavily towards a ‘yes’ answer”. It was concluded that the correct approach is for the skilled man to be told of the variant, but not actually given a working example. This seems entirely consistent with the later ruling of the Court of Appeal in Amgen.

The Hearing Officer noted that in many instances if a variant passes the first Question, it may more or less inevitably pass the second Question as well, but he pointed out that in Sunderstrand v Safe Flight Instrument [1994] FSR 599 the Patents County Court commented that because of the state of technical knowledge at the time, even if the first test had been passed, the second test would not because the skilled reader would not have expected the relevant changes to have had no material effect. As in Amgen, this was a hypothetical. The first test was not passed. We still await a real case.

Comment on our Survey of the Court of Appeal Decisions

Is the second Question necessary?

The first and second Protocol Questions are questions of fact requiring enquiry into the evidence. As we see from our table, with just one exception, the second Question flows with the first Question. More typically, if the variant would have a material effect upon the way the invention works, the second Question need not be answered and indeed cannot be answered. If, on the other hand, the evidence shows that the variant had no material effect on the way the invention works, then it is generally obvious to the skilled reader. Otherwise, if it is not obvious to the skilled reader, this is a strong indication that the variant has a material effect on the way the invention works.

How much knowledge of the alleged infringement do we impute to the skilled reader?

In American Home Products v Novartis, [2001] RPC 8, Aldous LJ touched on the question of how much knowledge we should impute to the hypothetical skilled reader in order 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. He said 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. Similarly, in Sara Lee v Johnson Wax [2001] WL 1347066, Aldous LJ said that to be fair to the public, the person to whom the specification is addressed should not have to build the device and test it to determine whether it is equivalent.

Now Amgen takes the Protocol analysis a step further in instances where, at the publication date of the patent, the patentee could not possibly have envisaged the feature or variant in question. Amgen 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.

And at what date is the skilled reader supposed to consider the alleged infringement?

In the detail, the Court of Appeal in Amgen moved the goalposts in terms of the date at which the hypothetical skilled reader has to consider the second Question (and indeed the first Question).

The House of Lords in Catnic said that the critical date is the date of the publication of the specification. As recently as July 2000 the Court of Appeal was continuing to quote that as the critical date (Wheatley v Drillsafe), but in view of the 1996 House of Lords ruling in Biogen, the Court in American Home Products considered evidence from the application date to determine sufficiency of disclosure and used that evidence to address the second Protocol Question. In Amgen, the Court did the same. Without clearly restating the rule, the Court looked at the evidence from the filing date (1984) to answer the second Protocol Question and justified this approach by saying “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.”

The Court is at least being consistent. 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.

Not very pro-patentee.

These clarifications are tough on the patentee expecting a twenty year monopoly for his invention and struggling to draft a claim that is not so broad as to be insufficiently supported by the description, i.e. not so broad as to encompass results which owe nothing to the teaching of the patent, and yet trying to obtain protection for future unforeseeable and indeed inventive developments that may well draw from the teaching of the patent. Did TKT draw from the teaching of the patent? Probably not. Probably TKT drew from all the other teachings in the field of EPO and other developments, but Amgen got there first and disclosed a principle of general application, and it may well be that TKT got there sooner than they might have done but for Amgen’s prior teaching.

Summary

1. The UK Courts follow the purposive construction approach as being the correct way to apply the Protocol on Interpretation. These are seen as consistent with each other.
2. The three Protocol Questions have been approved by the Court of Appeal as being a tool to assist in applying a purposive construction.
3. In practice, the first and second Questions stand or fall together. Only in theoretical cases where the technology has moved on considerably since the filing date do we see the likelihood that the second Question might fail where the first question succeeds.
4. The second Question (“Would it have been obvious to the skilled reader that the variant has no material effect upon the way the invention works?”) is to be judged at the filing date of the application.
5. The UK approach differs from that of other Courts in Europe, in particular by asking the third Question (“Would the reader have understood from the claim language that strict compliance with the primary meaning was essential?”) This is very much a part of UK law and non-infringement is frequently found by asking this question alone.
6. With few exceptions, the cases from the higher courts which have found infringement on a non-literal interpretation have merely required descriptive adjectives or adjectival phrases to be stretched to encompass the infringing article. In general, words in claims cannot be ignored or substituted.
7. The case law emphasizes the importance of good, broad claim drafting. Practitioners should attempt to anticipate progress of technology and not rely on any doctrine of equivalents. Each term in a claim should be viewed from the presumption that it is intended to limit the scope of the claim, as Courts do not necessarily seek out the draftsman’s reasons for adopting a term that may limit the claim.
8. It is advisable to review the scope of the claims immediately prior to grant to ensure that they encompass variants of the originally described invention made possible by progress in technology since the filing date (without, of course, amending the claims so as to add new matter).
9. There is great value in continuing the long-established drafting practice of claiming “means for” performing a function or achieving an aim, provided the resulting claim is not so broad as to encompass embodiments that owe nothing to the teaching of the patent or any principle disclosed.