Accord Healthcare Limited & Ors v The Regents of the University of California & Anor

In patent obviousness appeals, the Court of Appeal should intervene only for an error of law or principle in the trial judge’s multifactorial, fact-sensitive assessment. Motivation to take a particular step is relevant but is not an essential condition of obviousness. There is no separate test for modifications described as immaterial, trivial or workshop modifications; the question remains whether the step was obvious in context. A small structural change does not necessarily have no material effect. An expert’s focus on the claimed difference, without explaining the skilled team’s objective or route from the prior art, may properly be treated as hindsight. The appeal was dismissed.

Six pharmaceutical companies appealed against Mellor J’s dismissal of their claims to revoke a European patent and supplementary protection certificate relating to enzalutamide. The judgment under appeal was [2024] EWHC 2524 (Pat).

The patent claimed RD162′, whereas the Poster and Slides relied on as prior art disclosed RD162. The structural difference was a cyclobutyl group in RD162 instead of geminal dimethyl groups in RD162′. The appeal was confined to obviousness over those two items. The central issues were whether the judge had erred by requiring a contextual reason or scenario for the proposed modification and whether he was entitled to find the expert evidence tainted by hindsight.

Appeal dismissed unanimously. Arnold LJ gave the leading judgment, with Snowden LJ and Zacaroli LJ agreeing.

1. The assessment of obviousness is a multifactorial and fact-dependent evaluation. The appellate court may intervene only for an error of law or principle. It is insufficient that the appellate court might have reached a different conclusion.
2. The structured Pozzoli approach remains a useful framework. Motivation to take a particular step is relevant but is not a necessary condition of obviousness. A particular obvious route is not rendered less obvious merely because other routes are also available.
3. There is no separate legal test for a modification described as immaterial, trivial or a workshop modification. The statutory question is whether the modification was obvious. Whether a small structural change would have a material effect depends on the context, and structural smallness alone is not determinative.
4. The judge was entitled to take account of the absence of any articulated objective or scenario in Professor Westwell’s evidence. His focus on changing the cyclobutyl group to geminal dimethyl groups, rather than explaining an obvious way forward from RD162, could properly be regarded as leading and hindsight-driven. The judge was also entitled to find that RD37 appeared more active than RD7, making the proposed change potentially a backward step.
5. As to the Slides, the technical reasoning was cogent and less clearly affected by hindsight, but the evidence still failed to establish a sufficient context for investigating RD162′. The apparent force generated in cross-examination did not require the appellate court to substitute its own evaluation for that of the trial judge. No error of law or principle was shown.

1. Court of Appeal (Civil Division): The appeals were dismissed. Arnold LJ’s judgment was agreed by Snowden LJ and Zacaroli LJ.
2. High Court of Justice, Patents Court: Mellor J dismissed the revocation claims by order dated 7 November 2024, for the reasons given in the judgment dated 8 October 2024, [2024] EWHC 2524 (Pat).