Kirin-Amgen Inc & Ors v Hoechst Marion Roussel Ltd & Ors

This appeal concerns construction, validity and infringement of a European patent for recombinant production of erythropoietin (EPO). The House of Lords applied Article 69 EPC and the Protocol on its interpretation to emphasise purposive construction: the extent of protection is determined by the claims as the person skilled in the art would understand them in their context. The court held that the phrase "host cell" in claim 1 should be understood, in the context of the specification, to mean a cell host to an exogenous DNA sequence encoding EPO; it did not extend to products made by activation of an endogenous gene as in TKT's gene-activation process. The court concluded that the claims did not cover TKT's GA‑EPO and dismissed Amgen's appeal on infringement. The patent was, however, revoked because claim 19 was insufficiently enabled (section 72(1)(c), Patents Act 1977) — the molecular-weight test distinguishing recombinant EPO from urinary EPO was not capable of reliable application — and claim 26 was anticipated (lack of novelty) as a product-by-process claim was not saved where the product was not shown to be necessarily distinct from the prior art. The appeal therefore ended with the revocation of the patent.

The patent proprietor (Amgen) sued for infringement in respect of importation into the United Kingdom of an erythropoietin product (GA‑EPO) made by Transkaryotic Therapies' gene‑activation process and Hoechst's proposed importing; TKT and Hoechst counterclaimed for declarations of non-infringement and revocation. The disputed patent disclosed the DNA sequence of EPO and claimed (inter alia) a DNA sequence for securing expression of EPO in a "host cell" (claim 1), recombinant EPO characterised as the product of expression of an exogenous DNA sequence (claim 19) and a polypeptide product produced by expression of a DNA sequence according to claim 1 (claim 26).

The principal legal issues were:

• construction of the claims under Article 69 EPC and the Protocol and the role of purposive construction and the Improver/Protocol questions;
• whether the claims extended to products made by activating an endogenous EPO gene (TKT's process) or were limited to expression of an exogenous EPO coding sequence;
• sufficiency of disclosure under section 72(1)(c) Patents Act 1977, in particular the practicability of the SDS‑PAGE molecular‑weight test in claim 19 and whether the specification enabled the full scope of the monopoly claimed.

The House of Lords held that the claims must be construed purposively as the person skilled in the art would understand them in context. "Host cell" in the specification was used consistently to mean cells transfected with exogenous or foreign DNA coding for EPO; the skilled reader would not have regarded an endogenous activated gene as falling within claim 1. Accordingly GA‑EPO did not infringe. The court then addressed validity: it concluded that claim 26, being a product‑by‑process claim, could not be treated as novel simply because it was made by a different process unless the product itself was necessarily different from the prior art; on the facts claim 26 lacked novelty and was anticipated. Claim 19 failed for insufficiency because the molecular‑weight criterion (SDS‑PAGE comparison with "erythropoietin isolated from urinary sources") did not provide a practicable, reliable test and the specification did not enable the invention clearly and completely to the extent claimed.

Remedies sought and decided: Amgen sought injunctive and declaratory relief for infringement; TKT and Hoechst sought declarations of non‑infringement and revocation. The House of Lords dismissed Amgen's appeal on infringement and allowed TKT's cross‑appeal on validity, revoking the patent for the reasons above.

This was an appellate decision. Amgen's appeal on infringement was dismissed because the claims, properly construed in context under Article 69 EPC and the Protocol, required expression of an exogenous DNA sequence in a host cell and therefore did not cover TKT's gene‑activation of an endogenous EPO gene. TKT's cross‑appeal on validity succeeded: claim 19 was revoked for insufficiency under section 72(1)(c) because the SDS‑PAGE molecular‑weight test was not a practicable, reliable way to distinguish recombinant and urinary EPO, and claim 26 was revoked for anticipation (lack of novelty) because a product‑by‑process claim cannot be treated as novel merely by reference to its method of manufacture where the product is not necessarily distinct from the prior art. The patent was therefore revoked.

First instance: trial before Neuberger J (detailed findings of fact on molecular weight, enablement and construction). Court of Appeal: [2002] EWCA Civ 1096 (Aldous, Hale and Latham LJJ) — held claims valid but no infringement. House of Lords: [2004] UKHL 46 (conjoined appeals) — judgment reversing Court of Appeal on validity and affirming that TKT's GA‑EPO did not fall within the claims.