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Idenix Pharmaceuticals Inc. v. Gilead Sciences Inc., Court of Appeal, London, UK, 8 November 2016, Case no. [2016] EWCA Civ 1089

The Court of Appeal has upheld Arnold J’s judgment on the Gilead v Idenix case, which concerned the validity of Idenix’s patent EP(UK)1 523 489 covering a family of nucleoside analogues for the treatment of hepatitis C and other Flaviviridae infections and whether it was infringed by Gilead’s hepatitis C drug sofosbuvir (brand name SOVALDI).

At first instance, Arnold J found that sofosbuvir infringed EP’489 but that the patent was invalid for lack of novelty and inventive step, insufficiency and added matter. In upholding the judgment, Kitchin LJ, giving the lead judgment, provided some interesting commentary on the following points:

Assessment of the Common General Knowledge

The parties disagreed as to how much information formed the CGK, with Idenix asserting that more information constituted CGK than Gilead. At first instance, Arnold J concluded that Idenix’s stance was an attempt to remedy deficiencies in the Patent.

Idenix appealed on one aspect of Arnold J’s finding, concerning whether the efficacy of 2’-methyl-up-2’-hydroxy-down nucleoside analogues in treating HCV was part of the CGK. The Court of Appeal rejected this ground of appeal and gave several useful examples on what does not constitute CGK:

·         A paper published online five months before the priority date and in print three months before the priority date, which was not picked up/reported on and was not the subject of comment by others in either of those periods, did not form part of the CGK even though it was printed in a leading journal in the field. There was no evidence that the paper had become generally known to the bulk of the wider community of medicinal chemists with an interest in anti-HCV research.

·         Three presentations given at a major conference in Savannah held shortly before the priority date were found not to form part of the CGK. The conference would not have been attended by all medicinal chemists with an interest in anti-HCV analogues; there was no evidence that the presentations attracted particular attention (even though Idenix’s expert was interested in them); they were not identified as highlights of the conference in relevant bulletins and there was no evidence they were picked up for publication before the priority date. Kitchin LJ held that, given these circumstances, Arnold J had been right to consider the numbers of relevant medicinal chemists who attended the conference when reaching his decision.

Court of Appeal approach to High Court findings on insufficiency/obviousness

The Court of Appeal restated that an appellate court would “be very cautious in differing from the judge’s evaluation” when considering findings on insufficiency and obviousness which had involved the lower court weighing up a number of factors.

Insufficiency – undue burden and literature searches

In deciding whether the Patent enabled the skilled person to make the claimed compounds without undue burden, Arnold J had held that the skilled person would not have conducted a literature search. Idenix argued that relevant literature searches formed part of the daily work of the average medicinal chemist. Upholding Arnold J’s approach, Kitchin J held that “in some circumstances, the skilled person may reasonably be expected to carry out a literature search in order to implement aspects of the teaching of a specification”. However, the requirement for this search will depend on “all the circumstances, including the nature and purpose of the search that is required”.

Novelty – entitlement to priority

Gilead had argued that the Patent was anticipated by a Gilead patent application, which itself claimed priority from a patent application filed before the priority date. Idenix challenged that Gilead was not the “successor in title” to the earlier patent application and, therefore, could not claim priority from it.

The Court of Appeal provided obiter commentary on whether evidencing the transfer of the equitable title to an invention is sufficient to make a party a “successor in title” to the invention pursuant to Article 4(A) of the Paris Convention. The issue here is that the Paris Convention does not expressly address the distinction in common law systems between legal and equitable title.

Arnold J had held that equitable title was sufficient, following his own decision in KCI Licensing v Smith & Nephew that “it must be the substantive rights…not…compliance with legal formalities that matter”. Kitchin J held that this approach “makes eminently good sense” but also commented that “there may be other materials and decision which bear on this issue and to which our attention has not been drawn”. He declined to go further, however, this statement would appear to leave the door slightly ajar for challenges to entitlement to priority that are based only on evidence of transfer of equitable title.

A copy of the judgment can be read here.

Headnote: Beth Williams, Marks & Clerk Solicitors LLP