Accord, Sandoz and Teva v The Regents of the University of California and Astellas Pharma [2024] EWHC 2524 (Pat)
This case concerned the validity of the first defendant’s patent and SPC which claim the compound enzalutamide (identified as RD162’) and its therapeutic use. This compound is marketed by Astellas under the brand name “Xtandi” for treating both hormone sensitive prostate cancer (“HSPC”) and hormone refractory prostate cancer (“HRPC”). The claimants challenged the validity of the patent on the basis of obviousness over two pieces of prior art, a Poster and Slides, both of which disclosed a molecule identified as RD 162. The only difference between RD162 and RD 162’ lay in the substituents at the bottom right of the central thiohydantoin ring, i.e. a cyclobutyl group and a geminal dimethyl respectively. The claimants also deployed a squeeze argument between obviousness and insufficiency based on implausibility for lack of technical contribution.
The judgment handed down by Mr Justice Mellor includes a detailed consideration of the application of primary expert evidence and the avoidance of hindsight and highlights the potential weakness of obviousness and plausibility arguments not developed in the evidence in chief. The judgment also includes the following points of interest:
- a recognition of the fact that the proposition that a seemingly small structural change is tantamount to an obviously immaterial one is not generally appropriate or applicable in medicinal chemistry;
- a useful summary of some of the main principles around obviousness, including a discussion of the differences between “immediately obvious” (obvious to develop) and “obvious to do a SAR” (obvious to do routine tests) arguments;
- an analysis of the role of motivation, and a reaffirmation of the principle that the skilled person of patent law makes compounds with some specific technical purpose in mind;
- an investigation into the extent to which competitive and patenting considerations should influence an obviousness analysis, based on what real-life teams would do. In particular, the Judge held that the normal expectation of the Skilled Team would be that the widest possible patent protection would be in the process of being sought and that would normally indicate that the development of a novel and protectable molecule starting from the prior art would require significant changes;
- a synopsis of the legal propositions relating to plausibility as derived from the CoA in Apixaban [2023] EWCA Civ 472; and
- an endorsement of the EPO case-law emphasising the absence of a requirement for an invention to be better than the prior art (in addition to it simply being new and non-obvious).
Anna Edwards-Stuart KC appeared for Accord and Sandoz, instructed by Pinsent Masons LLP.