On 12 July, the Supreme Court handed down their decision in the case of Eli Lilly vs Actavis.
Katherine Wright, chemistry patent attorney, comments on the case and this shift in claim interpretation.
This case has been making its way through the courts for some years, and many people are familiar with the subject matter. For those that aren’t, here is a quick recap.
Eli Lilly hold a European patent with claims directed to the use of the salt pemetrexed disodium in combination with vitamin B12 for the treatment of cancer. The specification mentions the general chemical class “antifolates” which includes pemetrexed disodium, but does not mention any other salts of pemetrexed. All of the examples in the specification involve pemetrexed disodium.
Actavis produced a product comprising vitamin B12 and pemetrexed dipotassium, an alternative salt of pemetrexed. Eli Lilly sued for infringement based on their patent. Both the previous decisions on this case had held that there was no direct infringement, although the Court of Appeal did state that there was indirect infringement.
The Supreme Court, however, have ruled that Actavis’ product directly infringes Eli Lilly’s patent.
The judgement considers the case law carefully, with particular reference to the famous Catnic, Improver and Kirin-Amgen cases which up until now have set the landscape for purposive construction and consideration of equivalents. However, the Supreme Court did not believe that these cases went far enough to take account of The Protocol of the Interpretation of Article 69, which states that “due account shall be taken of any element which is equivalent to an element specified in the claims”, and reformulated the test originally laid out in Improver as follows:
1) Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, i.e. the inventive concept revealed by the patent?
2) Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?
3) Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?
The main alteration is the second question, which now imbues the skilled person with the knowledge that the variant works, whether or not this would have been obvious.
In this case, the answer to all three questions was yes: pemetrexed dipotassium achieves substantially the same result in substantially the same way as pemetrexed disodium; knowing that pemetrexed dipotassium works, as it is an alternative salt of the same active compound it would be obvious that it works in the same way as pemetrexed disodium; and finally, the specification does not clearly imply that the patentee intended strict compliance with the limitations in the claims. Thus, direct infringement of the patent was found.
The judgement also touches on the subject of the file wrapper. The original claims of the patent application referred to an antifolate, and this was amended to pemetrexed disodium during prosecution. Amendment simply to pemetrexed was not allowed by the EPO, as it was held to extend the subject matter of the application. The judgement considers this, but states that whether or not this objection by the examiner was correct, it has no bearing on whether or not interpretation of the final form of the claims should limit the scope of protection to pemetrexed disodium, or whether it should encompass other pemetrexed salts.
We will provide further commentary on this case and its fallout over the coming weeks, as we begin to see what impact this shift in claim interpretation has.
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