UK: Kirin-Amgen Inc and Others v. Hoechst Marion Roussel Limited and Others [2004] UKHL 46

On 21st October, 2004 Hoechst Marion Roussel Limited and Transkaryotic Therapies Inc (together referred to as "TKT") won their five year battle against Kirin-Amgen Inc ("Amgen").


The dispute between Amgen and TKT relates to the production of erythropoietin ("EPO"). EPO is produced in the kidneys in minute quantities. It was discovered that EPO had the useful property that it stimulated production of red blood cells and as a result it was very valuable for the therapeutic treatment of anaemia.

Amgen invented a process of producing EPO by recombinant DNA technology. For this invention Amgen was granted a European Patent (EP0148605B2). Essentially, Amgen had discovered a way of inserting the genetic code for the expression of EPO (or a part of the EPO protein) into a host cell. The cell would then take the genetic code for EPO and express the protein as part of its natural function. Amgen’s patent was directed to this invention.

TKT developed a different method of producing EPO. Almost all cells within the human body contain the full genetic code for the human body. In other words, the cells contains all the information required to produce any protein that the human body requires. However, although each cell is capable of producing any protein the human body requires, the ability of a cell to express most of the proteins is suppressed so that the cell only produces the proteins which are required for that cell’s particular function. For example a liver cell will only produce proteins which are required for the functioning of the liver. TKT discovered a way to "switch on" a cell’s natural ability to express EPO. This method was unknown at the priority date of the patent.

Hoechst Marion Roussel Limited started importing EPO into the UK. Amgen issued proceedings for infringement of Amgen’s patent. As a concerned party TKT also joined the proceedings.

The claims which Amgen claimed were infringed were Claim 19 and 26. However, Claim 26 is a dependent claim based on Claim 1. Therefore the relevant claims were:

Claim 1

"A DNA sequence for use in securing expression in a procaryotic or eucaryotic host cell of a polypeptide product having at least part of the primary structural [conformation] of that of erythropoietin to allow possession of the biological property of causing bone marrow cells to increase production of reticulocytes and red blood cells and to increase [haemoglobin] synthesis or iron uptake, said DNA sequence selected from the group consisting of [certain DNA sequences coding for EPO disclosed in the patent]."

Claim 19

"A recombinant polypeptide having part or all of the primary structural conformation of human or monkey erythropoietin as set [in certain DNA sequences coding for EPO disclosed in the patent] or any allelic variant or derivative thereof possessing the biological property of causing bone marrow cells to increase production of reticulocytes and red blood cells to increase haemoglobin synthesis or iron uptake and characterised by being the product of eucaryotic expression of an exogenous DNA sequence and which has a higher molecular weight by [determined by a standard technique] technique from erythropoietin isolated from urinary sources."

Claim 26

"A polypeptide product of the expression in a eucaryotic host cell of a DNA sequence according to any of claims 1 [and other dependent claims]."

In response, TKT claimed that its method was not within Claim 19 or 26 and accordingly could not infringe them. In addition, it claimed that Claim 19 was bad for insufficiency and further Claim 26 was anticipated (i.e. not new) because the product which it claimed was EPO was known and formed part of the state of the art at the priority date.

Interpretation of the Claims

According to the House of Lords the first step in determining whether any infringement of the patent has occurred is to correctly construe the claims of the patent.

The claims of the patent require interpretation because as the judgement points out, Article 69 of the European Patent Convention ("EPC") (which is incorporated into English domestic law under s60 and s125 PA 1977) states that:

"the extent of the protection conferred by a European Patent or a European Patent Application shall be determined by the terms of the claims. Nevertheless, the description and drawings shall be used to interpret the claims."

An invention will only be protected if reference is made to it within the claims. Indeed the judgement rejects the notion of equivalence which would extend the protection outside of the matter contained in the claims. Therefore determining what falls within the scope of the claims becomes of critical importance.

In determining the extent of protection provided by the claims, regard should be had to the Protocol on the Interpretation of Article 69 (the "Protocol") which requires that Article 69 should not be read as to mean that the claims are given a literal meaning nor should the claims be treated a mere guidelines. Rather the correct treatment is a position between the two extremes which provides a fair protection for the patentee with a reasonable degree of certainty for third parties.

In construing the claims the correct approach to take is the objective test of: what would a reasonable person to whom the utterance was addressed have understood the author to be using the words to mean? In applying this test, regard should be taken to the audience that is being addressed and the knowledge and assumptions which one attributes to that audience. In other words: what would a person skilled in the art understand the patentee to be using the language to mean? This is the principle of "purposive construction" which Lord Diplock proposed in Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183, 243 and is consistent with the Protocol.

As regards minor variations to the invention, the judgement makes it clear that the background knowledge of the person skilled in the art is relevant to the interpretation of the claims. The point here is whether or not the skilled person would have understood that the patentee was intending to limit its claims strictly so as not to encompass the variant. This again is relevant to the purposive construction as proposed in Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183, 243. In arriving at a purposive construction the House of Lords referred to Improver Corporation v Remington Consumer Products Ltd [1990] FSR 181, 189 under which the well known "Improver Questions" (and subsequently called the "Protocol Questions" in Wheatly v Drillsafe Ltd [2001] RPC 133, 142) were formulated. The House of Lords stressed that the Protocol Questions were no more than guidelines and should not be treated as legal rules on the interpretation of patent claims. The Protocol Questions were there to assist in arriving at a purposive construction only. Further, in certain circumstances, such as the invention of new technology, they were difficult, if not impossible to apply, in a sensible manner. Accordingly, in such situation, regard should only be had to Article 69 and its accompanying Protocol.

Product-by-Process Claims

It had been the past practice in the UK to allow product-byprocess claims. A product-by-process claim is a claim which claims the end product if that product is made by a patented process. The reason for allowing such claims was purely historical. Up until the enactment of the Patents Act 1977 the scope of protection conferred by a patent was undefined. Thus a product-by-process claim had the advantage that a patentee could pursue not only the user of its patent process but any person who dealt in the resulting product. The EPC in Article 64(2) removes the requirement for product-by-process claims as it expressly states that products directly obtained from a patented process are protected. The UK enacted this provision in s60(1)(c) Patents Act 1977. The result of Article 64 is that the European Patent Office will reject product-by-process claims except in the limited situation where the product is new (new in the sense of never being discovered) and the product cannot be described except by reference to its method of manufacture (International Flavours & Fragrances Inc [1984] OJ EPO 309). The UK continued to accept product-by-process claims even after the enactment of the Patents Act 1977. As a result the House of Lords stated that this practice of accepting product by- process claims must cease to bring the UK into line with European Patent Office and the other signatory states to the EPC. As a result, a patentee must rely on s60(1)(c) in respect of enforcing its rights if its patent process is being infringed.


The House of Lords also took time to further clarify its guidance on sufficiency as it was first described in its leading judgement in Biogen Inc v Medeva plc [1997] RPC 1, 48. The law on sufficiency is contained in s72(1)(c) Patents Act 1977. This provides that if the specification of the patent does not disclose the invention clearly enough and completely enough to be performed by a person skilled in the art the patent will be insufficient and therefore invalid. According to Biogen, this means that the disclosures made in the specification must allow a person skilled in the art to perform the invention across the whole range of claims contained in the patent. To determine whether a patent is sufficient it is necessary to identify precisely the nature of the invention. In order words, what does the patent teach? Once the invention is identified then a comparison between the subject matter contained within the proper interpretation of the claims and the teaching contained in the patent specification is required. If the person skilled in the art cannot perform the invention across the range of the claims then the patent will be insufficient. If the claims contain general terms then the claim will be sufficiently enabled if the person skilled in the art would reasonably expect the invention to work with anything which falls within the general terms. There is no requirement for the patentee to show that everything that could fall within the claims has been tried.

Application of these Principles to the Patent in Suit

Claim Interpretation

After construing Claim 1 and Claim 19 the House of Lords found that none of these claims were infringed. Essentially, on the evidence presented before it, the House of Lords found that a reasonable person skilled in the art would have understood the claims to be concerned with the protection of Amgen’s method of producing EPO. The person skilled in the art would not have understood the claims to be directed to TKT’s method of production. Accordingly, the House of Lords found there to be no infringement. As TKT’s method of production was not within the scope of Claim 1 it was also not within the scope of Claim 26 as this was dependent upon Claim 1. Therefore, Amgen’s claim for infringement was dismissed.


The House of Lords then found that as a matter of construction Claims 19 and 26 were product-by-process claims. It essentially found that Claim 26 was attempting to claim EPO. This claim could not be allowed because EPO was a known product at the priority date and thus formed the state of the art. The EPO produced by Amgen’s method was no different from the EPO that had been isolated before from urine even though it appeared that Amgen had convinced the European Patent Office that its EPO was different (and therefore new) when it prosecuted the patent application and thus falling within the exception in International Flavours & Fragrances Inc. As a result, Claim 26 was anticipated.


Claim 19 tries to distinguish the EPO produced by the Amgen method from the EPO obtained from urinary sources by reference to its higher molecular weight when measured by a standard technique applied in the field of biotechnology. The problem here is that the molecular weight of EPO obtained from urinary source varies according to the source and the method of purification. Further urinary EPO is extremely difficult to isolate in any quantity. The specification did not give the person skilled in the art any idea as to whether the EPO he was making would fall within Claim 19 or not. Further, the use of the reference to Amgen’s EPO being a higher molecular weight was artificial so as to allow the claim to be granted by the European Patent Office. As a result the specification did not enable the person skilled in the art to perform the invention as provided in Claim 19. Accordingly Claim 19 was invalid for insufficiency.


This is the first decision from the House of Lords (the UK’s highest court) based on the current UK patent law. The decision provides important clarification in the areas relating to the interpretation of patent claims, product-by-process claims and sufficiency.

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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