Walker Morris in London sent a note regarding the October, 2004, opinion in the patents case Kirin-Amgen v. Hoechst Marion Roussel. The case was the first opportunity for the House to consider the critical question of the extent of protection conferred by a patent under the provisions of the European Patent Convention (EPC), which were incorporated into UK law by the Patents Act 1977.

The dispute between Amgen and Transkaryotic Therapies, Inc. (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 anemia.

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. Amgen’s patent was directed to this invention. TKT developed a different method of producing EPO. 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. Amgen sued for infringement of Amgen’s patent.

Amgen, who’s claim was to a DNA sequence for securing the expression of EPO in a ‘host cell’,argued that ‘host cell’ meant a cell that hosted exogenous DNA so that TKT’s control sequence therefore infringed the claim. TKT argued for a narrower interpretation, that is, a cell that hosted EPO-encoded DNA. The relevant claims were:

Claim 1

“A DNA sequence for use in securing expression in a prokaryotic or eukaryotic 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 [hemoglobin] 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 hemoglobin synthesis or iron uptake and characterized by being the product of eukaryotic 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 eukaryotic 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 because the product which it claimed was EPO was known and formed part of the state of the art at the priority date.

At trial, Amgen’s patent was found valid and infringed. The Court of Appeal allowed TKT’s appeal on infringement, but upheld on validity. Both sides appealed to the House of Lords: Amgen on the question of infringement, TKT on the question of validity. Lord Hoffmann found entirely in TKT’s favor: the patent was not infringed, because TKT’s EPO was made in a way not described in the patent, and was invalid, because not new.

The court accepted that a claim could cover products or processes that involved the use of technology unknown at the time the claim was drafted, but the question was whether the person skilled in the art would understand the description in a way that was sufficiently general to include the new technology. The person skilled in the art would have not understood the claim to include the process of gene activation. The court took the view that one must ask “What would a person skilled in the art have thought the patentee was using the language of the claim to mean?”

The invention was held to be a particular process whereas the patent claim related to a particular product. The court held that the claim was anticipated by an earlier product. For Amgen to succeed in its action for infringement, the process itself should have been patented.

In conclusion the judge observed: “…it is clear that Amgen have gotthemselves into difficulties because, having invented a perfectly good and ground-breaking process for making EPO and its analogues, they were determined to try and patent the protein itself, notwithstanding that, even when isolated, it was not new.>

What this means is that the claims as understood by the person skilled in the art rule. There is no room for any doctrine of equivalents.

This will put a heavier burden on patentees to say exactly what they mean for claim scope. Meanwhile, competitors will be able to get closer to the claim scope of issued patents without infringing.

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