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

Factual and Procedural Background

Company A, a pharmaceutical firm, owns European Patent EP 148605B2, which teaches how to produce the hormone erythropoietin (“EPO”) using recombinant DNA technology. Company B, a competitor, developed an alternative method—referred to as “gene activation”—to manufacture the same protein (“GA-EPO”) and planned to import it into the United Kingdom. Company A sued for infringement; Company B counter-claimed for declarations of non-infringement and for revocation of the patent.

In the High Court, Judge Neuberger held that claim 19 of the patent was invalid for insufficiency, but that claim 26 was valid and infringed. The Court of Appeal reversed in part, upholding the validity of both claims but finding no infringement. Both parties appealed to the House of Lords: Company A contended that the Court of Appeal construed the claims too narrowly, while Company B challenged the findings on validity (anticipation and sufficiency). The present opinion resolves those cross-appeals.

Legal Issues Presented

1. How should the scope of protection conferred by the patent claims be determined under Article 69 EPC, the Protocol on its interpretation, and the Patents Act 1977?
2. Whether the product GA-EPO infringes claims 19 or 26 when manufactured via gene activation rather than by inserting an exogenous EPO-coding sequence.
3. Whether claim 26 lacks novelty (anticipation) because the resulting EPO is chemically identical to naturally occurring urinary EPO.
4. Whether claim 19 is insufficient because the patent fails to enable the skilled person to determine infringement using the “higher molecular weight by SDS-PAGE” criterion.
5. Whether the specification is sufficient in respect of breadth (all recombinant technologies), cell varieties, and EPO analogues.

Arguments of the Parties

Company A’s Arguments

• The term “host cell” in claim 1 encompasses cells containing an endogenous EPO gene so long as some exogenous DNA (e.g., regulatory sequences) is present; therefore GA-EPO falls within claims 19 and 26.
• Claims should be construed purposively to cover future recombinant technologies unknown at the priority date, including gene activation.
• Claim 26 is novel because expression in a eukaryotic host using the patented DNA sequence inevitably produces an EPO glycosylation pattern distinct from urinary EPO.
• Claim 19 is sufficiently clear: any skilled person can apply the SDS-PAGE test against a sample of urinary EPO.

Company B’s Arguments

• “Host cell” in claim 1 refers only to cells into which an exogenous EPO-coding DNA sequence has been introduced; GA-EPO is expressed from an endogenous gene and therefore lies outside the claims.
• Article 69 EPC bars extension of protection beyond the claims; purposive construction does not justify including undisclosed technologies.
• Claim 26 lacks novelty because recombinant EPO and urinary EPO can be chemically indistinguishable; defining a product by its manufacturing process does not confer novelty.
• Claim 19 is insufficient: variability among urinary EPO preparations makes the molecular-weight comparison unworkable; the patent gives no guidance on which reference sample to use.
• The patent fails to enable expression in non-CHO cells, fails to enable all recombinant technologies, and fails to teach how to identify functional analogues.

Table of Precedents Cited

Court's Reasoning and Analysis

Claim Construction and Infringement. The House endorsed purposive construction under Article 69 EPC. The skilled reader would interpret “host cell” in claim 1 to mean a cell into which an exogenous EPO-coding sequence has been inserted. Because Company B’s gene-activation method employs an endogenous gene, GA-EPO is not the product of “expression of an exogenous DNA sequence” (claim 19) nor the product of expression “in a host cell of a DNA sequence according to claim 1” (claim 26). Consequently, neither claim is infringed.

Use of the “Protocol Questions.” The Court explained that the Improver questions are merely aids; they cannot override the central statutory test. In highly technical contexts they may add little and can distract from the real inquiry: what the skilled person would understand the patentee to mean.

Novelty (Claim 26). The Court rejected the earlier finding that recombinant EPO is necessarily different from urinary EPO. On the High Court’s factual findings, there is no inherent chemical distinction. Relying on EPO case-law (International Flavors) and Article 64(2) EPC, the Lords held that defining a known product solely by reference to its method of manufacture does not confer novelty. Claim 26 was therefore anticipated and invalid.

Sufficiency (Claim 19). Claim 19 relies on a higher molecular weight “by SDS-PAGE” relative to “erythropoietin isolated from urinary sources.” Evidence showed significant variability in urinary EPO preparations; the patent gave no guidance on which reference sample to use. Because a skilled person could not ascertain, without undue effort, whether a given product fell inside or outside the claim, the disclosure was insufficient under section 72(1)(c) Patents Act 1977.

Other Sufficiency Grounds. The Court dismissed objections based on cell-variety and breadth, holding that those points did not arise once infringement failed; it acknowledged, however, that had the claims been construed broadly enough to cover all recombinant technologies, the breadth objection “may well have been a good one.” The analogue-sufficiency issue was left open because the relevant claims were already invalid.

Holding and Implications

Holding: the House of Lords dismissed Company A’s appeal, allowed Company B’s cross-appeal, and ordered that European Patent EP 148605B2 be REVOKED on grounds that (a) claim 19 is insufficient and (b) claim 26 lacks novelty; no infringement was established.

Implications: The judgment re-affirms that (1) claim construction in the United Kingdom is governed by purposive interpretation anchored in the claim language; (2) Article 69 EPC forecloses any doctrine that extends protection beyond the claims; (3) product-by-process claims will fail for lack of novelty where the product is not demonstrably different from prior art; and (4) insufficient clarity in a pivotal test renders a claim invalid. The decision aligns UK practice with EPO standards and signals to patentees that broad, technologically open-ended claims must be fully enabled and clearly delimited.