The UK Supreme Court (SC) has today handed down its judgment in the on-going dispute between Eli Lilly and Actavis relating to anti-cancer drugs including pemetrexed. It was announced last week that the SC had found in favour of Eli Lilly, by concluding that Actavis’ products directly and indirectly infringe Lilly’s patent in the UK, France, Italy and Spain. The SC’s finding on direct infringement differs from the previous High Court and Court of Appeal decisions, and the reasoning is of great significance for determining infringement of equivalents in the UK.

The infringement issue centred on whether Actavis’ pemetrexed products (containing the active ingredients pemetrexed diacid, dipotassium or ditromethamine) would infringe the claims of Lilly’s European patent, EP1313508B. The patent claims were directed to use of pemetrexed disodium (an antifolate) in combination with vitamin B12 for the inhibition of tumour growth in mammals. Since Actavis’ products were clearly not within the literal wording of Lilly’s claims, the SC was required to consider in detail how one assesses the scope of protection of a patent claim, particularly with respect to equivalents.

In paragraph 54 of the judgment, Lord Neuberger stated: a problem of infringement is best approached by addressing two issues, each of which is to be considered through the eyes of the notional addressee of the patent in suit, i.e. the person skilled in the relevant art. Those issues are: (i) does the variant infringe any of the claims as a matter of normal interpretation and, if not, (ii) does the variant nonetheless infringe because it varies from the invention in a way or ways which is or are immaterial? If the answer to either issue is “yes”, there is an infringement; otherwise, there is not.

He went on to note that in considering the second issue, the “Improver questions” (as set out in the case of Improver Corp v Remington Consumer Products Ltd [1990] FSR 181) were useful. However, he considered it appropriate to reformulate the second question such that the questions to be asked are: i) 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? ii) 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? iii) 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?

Applying these questions to Actavis’ products, it was concluded that the answers to questions (i) and (ii) were yes. It was noted that the SC’s answer to the second question differed from the High Court and Court of Appeal’s conclusions because in these previous decisions, it was considered that the notional addressee should consider the obviousness question without knowing that Actavis’ products worked. The SC was of the opinion that this test was too strict, and that the second question should assess obviousness with knowledge that the variant does achieve substantially the same result. Regarding the third question, the SC found the answer to be “no”, particularly taking into account the teaching of the specification as a whole, and stated that the Court of Appeal’s contrary view placed too much weight on the words of the claim.

Turning to the effect of the prosecution history, the SC stressed that the reference to the prosecution history in determining the scope of a patent should be limited. It was stated by Lord Neuberger at paragraph 88 that: “my current view is that reference to the file would only be appropriate where (i) the point at issue is truly unclear if one confines oneself to the specification and claims of the patent, and the contents of the file unambiguously resolve the point, or (ii) it would be contrary to the public interest for the contents of the file to be ignored.”

In the proceedings before the High Court, it was noted by the judge (in concluding non-infringement of Lilly’s patent) that the patentee had been required to limit their claims to the disodium salt because claims reciting simply pemetrexed were rejected under Art. 123(2) EPC, for added matter. However, the SC did not consider the findings of the EPO to be a bar to construing Lilly’s claims such that the scope of protection extended to Actavis’ products.

This decision, particularly the reformulation of the Improver questions, has important implications for claim interpretation before the UK courts. It will be interesting to see whether the reasoning provided by the SC will significantly broaden the scope of protection with respect to equivalents in the UK.