House of Lords Rules out Doctrine of Equivalents in KirinAmgen v. TKT

It is twenty years since the House of Lords ruled on patent claim interpretation, and adopted the principle of “purposive construction” (Catnic v. Hill & Smith [1982] RPC 183). The patent in question was granted under the “Old” (1949) Patents Act. In the meantime, with the enactment of the 1977 Act, we have the Protocol on Interpretation of Article 69 of the European Patent Convention to be applied to claim interpretation (see box overleaf).

The test that has evolved in the Patents Court and the Court of Appeal is summarized in three questions formulated by Mr. Justice Hoffman (as he then was) in Improver v. Remington [1990] FSR 181, and subsequently referred to as the “Improver Questions” but more recently dubbed the “Protocol Questions” (see Autumn 2002 Patent issues). Have we been using the right test all these years? Is “purposive construction” still the rule under the Protocol? Or might the balance tip further towards “fairness to the patentee”, perhaps in the form of a Doctrine of Equivalents?

At last the House of Lords has had an opportunity to consider these questions, and the result is the end of speculation. The Protocol Questions are a tool not necessarily useful in every case. Purposive construction continues but is perhaps less radical than many may have thought. There will be no Doctrine of Equivalents.

The House of Lords’ decision (Kirin-Amgen and others v. Hoechst Marion Roussel and others 21 October 2004) is the culmination of UK proceedings in a long-fought battle between Kirin-Amgen (Amgen) and Transkaryotic Therapies (TKT) over biotech methods of manufacture of the hormone erythropoietin (EPO). EPO stimulates red blood cell production and is useful in treating a range of disorders including anaemia, lung disease, certain heart conditions, cancer, rheumatoid arthritis and HIV. EPO produced by Amgen is reported to generate over $1bn per year in sales worldwide. It is also used illegally by athletes to boost performance.

 

THE FACTS

The facts of the case are complex and are summarized in our Autumn 2002 edition of this newsletter, where readers will also find the independent claims at issue. That newsletter is available here.

Amgen had claims to:

• a DNA sequence (claim 1) for use in expressing EPO in a “host” cell;
• a recombinant polypeptide (claim 19) having the structure of EPO as defined
• in certain tables; and
• a polypeptide product (claim 26) of the DNA sequence claimed.

(They also had claims to a method of producing EPO, but these were not in dispute - TKT used a different method.)

 

CONSTRUCTION AND INFRINGEMENT

EPO itself was not new, but the inventor, Dr. Lin, isolated the DNA sequence coding for it and described this in the patent application. Amgen’s principal difficulty was in claiming the product of their process, and having such claims construed broadly enough to encompass TKT’s product of the different process.

“There is no presumption about the width of the claims. A patent may, for one reason or another, claim less than it teaches or enables.”

Claim 1 suffered from difficulty over interpreting what was meant by the term “host”. Was it necessary that the host cell should be host to foreign DNA coding for EPO? Or might it extend to endogenous DNA that codes for EPO when activated by some other foreign DNA?

The trial judge at first instance had concluded from the evidence that a cell (in the context of the claim) is not a “host cell” unless it is host to exogenous DNA encoding for EPO. (On appeal, counsel for Amgen argued that the judge was reading words into the claim, but the House of Lords disagreed). The judge had then applied the Protocol Questions to see whether the “variant” (i.e. a cell that is host to some other DNA sequence such as TKT’s viral promoter sequence) might fall within the ambit of the claim.

The judge thought the invention lay in the discovery of the sequence of the EPO gene and the associated information, such that any method of making EPO which used that information would be an immaterial variant. The Court of Appeal, on the other hand, thought the invention was a way of making EPO. The House of Lords agreed with the Court of Appeal. The judge’s initial interpretation of the claims gave the answer to the question of infringement. The Protocol Questions merely clouded the issue.

“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.”

A principal reason why the Protocol Questions gave rise to difficulty is set out in our earlier newsletter. The second question asks “Would it have been obvious that the variant had no material effect on the way the invention works?” If the variant (as here) involved a new, emerging technology, how could it have been obvious that it would have no material effect - unless you imbue the skilled person with some hypothetical knowledge of the variant at a date before the variant existed?

The Court of Appeal followed that reasoning to its logical conclusion, which was that the variant fell outside the claim. Lord Hoffman, for the House of Lords, bypassed his Protocol Questions and reached the same result from straightforward purposive construction of the claims.

So is this the end of the Protocol Questions? No – they may well have their uses in more mature or slower-moving technologies (if such things exist).

"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."

 

INSUFFICIENCY – BREADTH OF CLAIMS

Since claim 1 was to be construed narrowly so as not to cover the TKT process, the question of whether the specification enabled that process (raised in the alternative as a “squeeze” argument) became irrelevant. Nevertheless, the House of Lords commented extensively on this very important point.

The Court of Appeal had said:

"The law contemplates that patents will not lack sufficiency even though the claims cover inventive improvements. If the law was otherwise there would be no room for patents which disclosed a principle of general application unless the specification described how to carry out later inventions using the principle."

The words “principle of general application” came from Lord Hoffman’s speech in Biogen v. Medeva ([1997] RPC 1 at pp 48-49). The judge, who had taken the view the invention lay in the DNA sequence, considered that invention to be a principle of general application. Lord Hoffman now explained that his words in Biogen are not “difficult or mysterious”. They simply refer to an element of the claim which is stated in general terms. Such a claim is sufficiently enabled if we can reasonably expect the invention to work with anything which falls within the general term.

In this case, the specification did not disclose a way of making EPO in sufficiently general terms to include TKT’s process, so even if they had been infringed, they would have been invalid for insufficiency. There was no reason for the skilled man to think that the TKT method would work just as well. It was not merely a version of the Amgen process. It was different.

 

INSUFFICIENCY – CLAIM AMBIGUITY

Amgen had a problem claiming the product of their process. The European Patent Office would not allow a product-by-process claim if the product itself was not new. So Amgen (all credit to their patent attorneys) formulated a claim (claim 19) to a recombinant polypeptide “having . . . the primary structural conformation of . . . EPO . . .which has higher molecular weight [than] EPO isolated from urinary sources”. This (they thought) distinguished their EPO from known EPO. But it turned out from the evidence that Amgen had made an underlying assumption that urinary EPO has a certain uniform molecular weight. The evidence showed that it varied widely.

TKT counter-claimed for invalidity of claim 19 on grounds of insufficiency.

The Court of Appeal below had set a five-factor test for insufficiency in cases of comparative tests:

i) the onus is upon the defendant to establish that the test is insufficient;

ii) The question of insufficiency has to be established at the filing date;

iii) it has to be decided by the court through the eyes of the skilled person;

iv) the skilled person is deemed to be seeking success rather than failure; and

v) lawyers can often think up puzzles at the edges of a claims but skilled persons are concerned with practicalities, not puzzles.

On appeal to the House of Lords, their Lordships concluded that the choice of urinary EPO had nothing to do with making the invention work. It was simply a criterion against which to test whether the claim was infringed. The concept of “success” or “failure” was irrelevant. One source of EPO was as good as another. If the skilled man had to guess which source the patentee had in mind, the specification was insufficient.

“American patent litigants pay dearly for results which are no more just or predictable than could be achieved by simply reading the claims.”

 

PRODUCT-BY-PROCESS CLAIMS

Claim 26 defined the invention as the product of the expression, in a eucaryotic host, of a DNA sequence according to claim 1. Was this a new product or merely the product of a new process?

The relevance of this question is that the Technical Board of Appeal of the European Patent Office has accepted that it is permissible to have a claim to a product defined in terms of a process of manufacture, but that such claims should only be granted in cases where the product cannot be satisfactorily defined by reference to its composition, structure or other testable parameter (T150/82 IFF/Claim Categories and others, see Case Law of the Boards of Appeal 4th Edition 2001, Section II B 6.3). This is reflected in the EPO Guidelines (Guideline C-III 4.7b).

The Court of Appeal in this case had held there to be no reason why the limitation of a claim to products produced by a process could not impart novelty to the claims.

The House of Lords disagreed, saying first and foremost that the claimed product must be new. A difference in the method of manufacturing an identical product does not make it new. It is only if the product is different but the difference cannot in practice be satisfactorily defined by reference to its composition etc. that a definition by process of manufacture is allowed.

In this case, the European Patent Office in granting the patent had found that rEPO according to Claim 26 was a new product because its glycosolation pattern would necessarily be different from that of known uEPO. The trial judge came to a different finding of fact. As a consequence there could be no basis for upholding claim 26.

 

Comment

Equivalents

Not only has the House of Lords firmly shut the door on any Doctrine of Equivalents, it has taken the Protocol on Interpretation of Article 69 and new Article 2 added to that protocol by the Munich Act of 29 November 2000 and turned these around to support a more rigid view. The Protocol says first and foremost that the extent of protection conferred by a European Patent shall be determined by the claims. Fairness to the patentee and third parties does not permit expansion of the words of the claims. To do so might invalidate the patent on the grounds of insufficiency.

The Munich Act says “due account shall be taken of any element which is equivalent to an element specified in the claims”. The House of Lords takes the view that if such an equivalent was known at the time of invention, then “due account” can be taken of it by assuming that if it is not claimed, it is disclaimed (and if it was not known at the time, then any claim which encompasses it is in grave danger of failing for insufficiency). This does not merely eviscerate any intention in the Munich Act to extend claim interpretation to equivalents, it turns any such intention on its head.

 

Sufficiency

It seems in the end it didn’t matter so much what was meant by the word “host”. In fact it probably didn’t matter whether the word was even present. The inclusion of the word meant the claim was valid but not infringed. If the word had been omitted or the claim had encompassed TKT’s process, the House of Lords would have held it to be invalid for insufficiency.

Biogen says a patent will be invalid if it claims every way of achieving a result when it enables only one way and it is possible to envisage other ways of achieving that result which make no use of the invention. Amgen reinforces that principle, even where those “other ways” cannot be envisaged at the time of filing.

This is a harsh result. In Biogen, Prof. Murray’s contribution to the art of Hepatitis B vaccines was to find, through trial and error, restriction enzymes that would cleave DNA at suitable restriction sites to produce fragments that could be introduced into a host so as to generate HBV antigens by recombinant DNA techniques. Prof. Murray did not sequence the relevant DNA but he claimed any DNA sequence coding for an HBV antigen. Amgen’s Dr. Lin, on the other hand, was the first to isolate the DNA sequence coding for EPO, and he described this in his patent application. It is harsh that he should be restricted to claiming only such methods of using his DNA as were envisaged by his patent application, to the exclusion of methods that use the DNA sequence he discovered but could not be envisaged at that time.

 

Product-by-Process Claims

Article 64(2) EPC extends the protection afforded by a process claim to a product directly made by that process. It is therefore unnecessary to claim the product defined by reference to the process. The House of Lords said it is important that the United Kingdom should apply the same law as the EPO and the other Member States when deciding what counts as new for the purposes of the EPC, notwithstanding that this means a change in a practice which has existed for many years. But their Lordships say the difference is unlikely to be of great practical importance, because a patentee can rely instead on the process claim and Article 64(2).