Kirin-Amgen Inc v Transkaryotic Therapies Inc (No.2)
Kirin-Amgen Inc. (K) was the proprietor of a European patent relating to the production of erythropoietin (EPO) by recombinant DNA technology. EPO was a hormone made in the kidney which stimulated the production of red blood cells. Transkaryotic Therapies Inc (T), a US corporation, had also developed a method of making EPO using a process called “gene activation”. K claimed that T’s EPO infringed the claims of K’s patent, and T applied for a declaration of non infringement and revocation of the patent.
The essential difference between K’s artificial EPO and T’s EPO was that the former was made by an exogenous DNA sequence coding for EPO which had been introduced into a host cell, whereas the latter was made by an endogenous DNA sequence coding for EPO in a human cell into which an exogenous upstream control sequence had been inserted. The relevant claims in the patent were for a DNA sequence for use in securing the expression of EPO in a host cell (claim 1), EPO which was the product of the expression of an exogenous DNA sequence (claim 19) and EPO which was the product of the expression in a host cell of a DNA sequence according to claim 1 (claim 26). Only claims 19 and 26 were alleged to have been infringed because T did not make any EPO in the UK, and the alleged infringement was by importation.
The judge held that claim 19 was invalid for insufficiency but that claim 26 was valid and infringed. The Court of Appeal held that both claims were valid but that neither was infringed.
K argued that as a matter of construction T’s process was within its claim because it involved using a “DNA sequence for use in securing expression of EPO in a host cell”. T argued that the patent should be revoked because claim 19 was invalid for insufficiency and claim 26 was invalid for anticipation.
Held (House of Lords):
House of Lords relied on Catnic Case and held that the principle of purposive construction as applied in Catnic was precisely in accordance with the Protocol on the Interpretation of the European Patent Convention 1973 Art.69. It was intended to give the patentee the full extent, but not more than the full extent, of the monopoly which a reasonable person skilled in the art, reading the claims in context, would think he was intending to claim. However the Court noted that it was important to distinguish between, on the one hand, the guidelines set out in Improver Corp for deciding whether equivalents fell within the scope of the relevant claims and, on the other, the principle of purposive construction established by Catnic. The latter was the bedrock of patent construction, whereas the former were mere guidelines which were more useful in some cases than others.
The judge had been right to hold that “host cell” in the context of the specification meant “cell which [was] host to an exogenous DNA sequence encoding for EPO” and on that basis had been entitled to find that claim 1 was to a sequence coding for EPO which was exogenous to the cell in which expression took place and that the person skilled in the art would not regard the endogenous coding sequence which expressed T’s EPO as falling within claim 1. It followed that T’s EPO was not the expression of a DNA sequence within claim 1 and therefore did not infringe claim 26 and by the same process of reasoning that the person skilled in the art would not regard T’s EPO as “the product of…expression of an exogenous DNA sequence” within claim 19.
A claim might on its proper construction cover products or processes which involved the use of technology unknown at the time the claim was drafted, but in the instant case the man skilled in the art would not have understood the claim as sufficiently general to include T’s gene activation method of producing EPO. Therefore T did not infringe any of the claims in K’s patent. The judge had been right to find that there was no difference between EPO made according to claim 26 and EPO which had been purified from urine and was already part of the state of the art.
The UK should apply the same law as the European Patent Office and the other Member States when deciding what counted as new for the purposes of the European Patent Convention 1973 and should not accept “product by process” claims as a matter of practice. Claim 26 would have been revoked in opposition proceedings and was therefore declared invalid on the ground of anticipation. The nature of the invention which the specification had to enable was a way of making EPO.
The judge had been right to conclude that claim 19 was invalid for insufficiency because the test for distinguishing EPO falling within claim 19 from EPO purified from urine by its molecular weight was in practice incapable of application. The patent was revoked on the grounds that claim 19 was insufficient and that claim 26 was anticipated.
At para 47, it was observed-
“The object is to combine a fair protection for the patentee with a reasonable degree of certainty for third parties. How is this to be achieved? The claims must be construed in a way which attempts, so far as is possible in an imperfect world, not to disappoint the reasonable expectations of either side. What principle of interpretation would give fair protection to the patentee? Surely, a principle which would give him the full extent of the monopoly which the person skilled in the art would think he was intending to claim. And what principle would provide a reasonable degree of protection for third parties? Surely again, a principle which would not give the patentee more than the full extent of the monopoly which the person skilled in the art would think that he was intending to claim. Indeed, any other principle would also be unfair to the patentee, because it would unreasonably expose the patent to claims of invalidity on grounds of anticipation or insufficiency.”