Mr. Justice Arnold’s 1 December 2014 judgment in Idenix Pharmaceuticals v Gilead Sciences is notable for many reasons other than its length and complexity. Perhaps chief among these is that it was delivered within nine months of the date of grant of Idenix’s patent; also the date on which fast-moving Idenix asserted its patent against Gilead. This article seeks to summarise in 1.57 pages what Arnold J said in 157 pages.

The patent. Following lengthy discussions concerning synthesis and chemistry of nucleoside analogues and testing of candidate compounds for antiviral activity, Arnold J moved on to Idenix’s PCT application, “a remarkable document” of 200 pages, and to the patent itself, half the size of the application but containing much irrelevant material. The seeds of a finding of insufficiency were sown liberally in His Lordship’s analysis of these documents.

Construction and infringement. Having first considered Idenix’s efforts to inflate the CGK so as to plug the gaps in the disclosure of the specification, Arnold J returned to the claims and the issues decisive for infringement. His Lordship first held that, in light of the specification, the term “phosphate” included a masked phosphate, which meant Gilead’s sofosbuvir compound fell within the claims. His Lordship then found that production of a claimed compound in vivo (in Gilead’s case, a metabolite of sofosbuvir) constituted indirect infringement of the claims because the skilled team would have prodrugs and metabolites in mind when reading the claims because they are discussed in the patent.

Priority and lack of novelty. The judgment next addresses whether Gilead’s own PCT application was entitled to the priority claimed from an earlier US application. This was relevant because Gilead’s application, if so entitled, anticipated 47 of the 49 claims of Idenix’s patent. The dispute centred on whether an (arguably unsigned) research and development agreement between two related companies was effective to assign the rights in the US priority document from the company that filed it to the company that filed the PCT application. Having heard a mini trial on the subject of US contract law, Arnold J held that it was.

Lack of inventive step and insufficiency for excessive claim breadth. Gilead’s contention in relation to lack of inventive step was of the less conventional type, that the claimed invention made no technical contribution to the art. As Idenix’s claims covered, “on a conservative estimate at least 50 billion compounds”, Idenix conceded it was not plausible that substantially all of the claimed compounds would have antiviral activity. For this reason, Idenix applied to amend the claims to narrow their scope, but this was not enough to save the patent on these grounds (and would have invalidated the patent by adding matter). In particular, Arnold J held that the patent was devoid of support, whether by experimental data or theory, for its assertion that the claimed compounds had antiviral activity, and it therefore made it no more plausible that those compounds would have antiviral activity than did the common general knowledge. In concluding that the claims were insufficient for excessive claim breadth, His Lordship relied on the same analysis, noting emphatically, “the Patent is setting the skilled team a substantial research project to select, synthesise and test the claimed compounds relying upon their own common general knowledge and claiming the results if they are successful.”

Insufficiency for undue burden. Idenix’s case that the skilled team could work the claimed invention in light of the teaching of the patent and their common general knowledge was decisively undermined by the failure of its own chemist to synthesise the claimed compounds over a two-year period using eleven distinct strategies. This serves as a reminder of the damage that the requirement to disclose relevant documents can do to a party’s case. Idenix was unable to rescue its position with experimental and expert evidence. Its experiments deviated from the procedure used by Idenix’s chemist, and the evidence of Idenix’s expert was tainted by hindsight because it assumed a literature search and a retrosynthetic analysis would yield outcomes that assisted Idenix’s case. Interestingly, Arnold J’s finding on this issue suggests that, where the skilled person addressing the problem would routinely undertake a literature search, the parties’ experts should conduct their own ex post facto literature search and base subsequent analysis on the outcome.

Alex May