CA-2025-001040 - [2025] EWCA Civ 903

Grounds 7-8: arbitrary selection

It must be assumed for the purposes of considering grounds 7 and 8 that at least claim 2 of the Patent is free from objection on plausibility grounds.

Ground 7 is that the judge was wrong in his approach to the issue of arbitrary selection. Ground 8 is that the judge failed properly to assess the contribution of WO 128 when considering whether the Patent made a technical contribution. Although counsel for AstraZeneca argued these two grounds together, it is important to distinguish between them.

The starting point for ground 7 is the final sentence of [59]. For convenience I will set this out again:

“If the patent claims a compound selected from a previously disclosed genus of compounds which are said to have a particular property, then that requirement is not satisfied if the compound does not in fact have some different or improved property compared to those previously individually disclosed (a new effect or an increase in an effect), or the patent does not make such improved property plausible.”

AstraZeneca contends that this is wrong in law, and that the judge ought to have held that, where the prior art merely asserted that the genus had a given advantage or property without rendering it plausible, then a subsequent patent may make a technical contribution by making the same assertion in respect of a selected compound and rendering it plausible. The judge rejected this argument at [271], but AstraZeneca argues that he was in error. I disagree. As the case law discussed by the judge makes clear, a selection from the prior-disclosed genus is only inventive if the selection makes a technical contribution because the selected compound in fact has some useful property which means that the selection is a technical advance. Mere plausibility is not enough for this purpose.

AstraZeneca also argued in its grounds of appeal that the technical contribution of the Patent was not merely that it made a plausible claim that dapagliflozin would be useful for the treatment of diabetes, but rather it made a claim to that effect which turned out to be true. This argument was rightly not pursued in AstraZeneca’s skeleton argument or oral submissions, because it is contrary to the way AstraZeneca put its case at trial as the judge explained at [266]-[268].

Given that I have rejected ground 7, success on ground 8 would not suffice for AstraZeneca to overturn the judge’s conclusion on arbitrary selection. I shall nevertheless address it. AstraZeneca argues that the judge went wrong because he compared what the Patent contributed to what WO 128 said, whereas he should have compared what the Patent contributed with what WO 128 contributed. AstraZeneca does not dispute that the relevant wording in the Patent is the same as that in WO 128, but it nevertheless contends that the quality of the disclosures is quite different. WO 128 makes an assertion about a class of compounds which it is common ground would at its narrowest (those covered by Formula IB) include millions of compounds, whereas the Patent is confined to dapagliflozin. AstraZeneca relies upon the principle, which is not in dispute, that it is easier to show a claim of narrow scope is plausible than a claim of broad scope.

In my judgment the judge was correct to reject this argument for the reasons he gave at [272]-[279] (see paragraphs 80-81 above). I would only add two points. First, counsel for AstraZeneca sought to attack the judge’s analysis of the expert evidence, but the judge’s findings are amply supported by that evidence. Secondly, counsel for the Claimants made a striking submission in support of the judge’s reasoning. Given the disclosure in WO 128, BMS could have filed 50 patent applications for compounds falling within Formula IB, including an application in respect of the compound of Example 12, and subsequently abandoned all 50 other than the one for dapagliflozin. On AstraZeneca’s argument, none of those applications would have been objectionable on the ground of arbitrary selection. What this submission highlights is the complete absence from the Patent of any basis for distinguishing between dapagliflozin and other compounds falling within Formula IB of WO 128 such as the compound of Example 12.