Kirin-Amgen Inc and others (Appellants) v. Hoechst Marion Roussel Limited and others (Respondents). Kirin-Amgen Inc and others (Respondents) v. Hoechst Marion Roussel Limited and others (Appellants) (Conjoined Appeals)

The extent of a European patent is determined by purposively construing its claims through the eyes of the skilled reader. Article 69 of the European Patent Convention permits no separate doctrine extending protection beyond those claims. Equivalents and the Improver questions may assist construction, but they are guides rather than rules.

An identical existing product does not become novel merely because it is made by a new process. A specification must also enable the invention across the full scope claimed. Uncertainty amounts to insufficiency where it makes performance or identification of the claimed product impossible without extensive investigation, rather than merely leaving a marginally uncertain boundary.

Kirin-Amgen Inc v Hoechst Marion Roussel Ltd concerned a European patent for producing erythropoietin by recombinant DNA technology. Amgen alleged that imported erythropoietin made by TKT's later gene-activation process infringed product claims 19 and 26. TKT and Hoechst sought declarations of non-infringement and revocation.

Neuberger J held claim 19 invalid for insufficiency, but held claim 26 valid and infringed. The Court of Appeal, [2002] EWCA Civ 1096, held both claims valid but neither infringed. In the conjoined appeals, Amgen challenged the finding of non-infringement, while TKT challenged validity for anticipation and insufficiency.

The central questions were how the claims should be construed under article 69 of the European Patent Convention, whether a product made by a new process was novel, and whether the specification enabled the claims across their full scope.

1. Disposition. Lord Hoffmann delivered the leading speech. Lord Hope, Lord Rodger, Lord Walker and Lord Brown agreed with it. The House unanimously dismissed Amgen's appeal, allowed TKT's cross-appeal and revoked the patent. Claim 19 was invalid for insufficiency under section 72(1)(c) of the Patents Act 1977; claim 26 was invalid for anticipation under section 72(1)(a).

2. Construction and infringement. Per Lord Hoffmann, article 69 of the European Patent Convention makes the terms of the claims decisive. The Protocol rejects literalism but does not permit protection outside the claims. The principle in Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183 accords with the Protocol: the question is what a skilled reader, reading the claims in context, would understand the patentee to mean.

   The Improver questions are guidelines for considering equivalents, not rules of law. They may be unhelpful where the real issue is the level of generality at which the invention was claimed. Lord Walker, with whose observations Lord Hope and Lord Rodger agreed, emphasised that the questions may distract from the single compulsory inquiry under article 69.

3. The skilled reader would understand the claims to require expression from an exogenous DNA sequence coding for erythropoietin. TKT's product was expressed by an endogenous human gene activated by an inserted control sequence. It therefore fell outside claims 19 and 26. A claim may encompass later-developed technology when its language is sufficiently general, but these claims were not framed at that level.

4. Novelty. An existing product does not become new merely because it is made by a new process. Article 64(2) protects products directly obtained by a patented process and removes the principal justification for treating product-by-process language as conferring novelty. The judge had found no necessary difference between the erythropoietin within claim 26 and previously known urinary erythropoietin. Claim 26 was therefore anticipated.

5. Sufficiency. The specification must enable performance across the full extent of the claimed monopoly. The invention must first be identified; the court then asks whether the skilled person can perform it. A general expression is enabled where the invention can reasonably be expected to work throughout that generality without testing every embodiment.

   Claim 19 used apparent molecular weight against unspecified urinary erythropoietin as its distinguishing criterion. Different samples produced different results, and the specification gave no means of selecting the appropriate comparator. This made it impossible to determine whether a product fell within the claim. The defect was insufficiency, not merely uncertainty at the claim's boundary.

1. House of Lords: In Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2004] UKHL 46, the House unanimously dismissed Amgen's appeal, allowed TKT's cross-appeal and revoked the patent.
2. Court of Appeal: In [2002] EWCA Civ 1096, the court held claims 19 and 26 valid but held that neither was infringed.
3. High Court: Neuberger J held claim 19 invalid for insufficiency. He held claim 26 valid and infringed. A neutral or report citation for this stage is not stated in the judgment.