Teva Pharmaceutical Industries Limited & Anor v Astellas Pharma Inc

For a medical-use patent, obviousness is assessed by asking whether the prior art, read with common general knowledge, made it obvious to try the claimed use with a reasonable expectation of success. A mechanism’s general therapeutic potential does not make every particular compound obvious, especially where the prior disclosure gives little guidance and the skilled team lacks confidence in success. The absence of human or human-tissue experiments does not itself answer the obviousness question where efficacy is plausibly disclosed. Technical-prejudice reasoning applies only where lack of obviousness rests on a perceived obstacle. Appellate intervention in this multifactorial assessment requires an error of law or principle.

Teva and Sandoz appealed against Meade J’s decision dismissing their claims to revoke a patent for mirabegron and the related supplementary protection certificate, and granting infringement relief to Astellas. The decision is reported at [2022] EWHC 1316 (Pat).

The patent claimed mirabegron, or a salt thereof, for treating overactive bladder. The appellants argued that the claimed use was obvious over Australian Patent Application AU 199889288, read with the common general knowledge concerning β3-adrenoceptor agonists. The central issues were whether the first-instance judge had applied the correct approach to obviousness, whether the patent needed to dispel uncertainties through human or human-tissue evidence, and whether the prior art made it obvious to try mirabegron with a reasonable expectation of success.

Arnold LJ gave the judgment, with Stuart-Smith LJ and Falk LJ agreeing. Both appeals were dismissed.

1. Obviousness involves a multifactorial evaluation. An appellate court should not interfere with the first-instance assessment absent an error of law or principle. That approach was supported by Actavis Group PTC EHF v ICOS Corp [2019] UKSC 15, [2019] Bus LR 1318, and was consistent with the general approach to evaluative decisions in Re Sprintroom Ltd [2019] EWCA Civ 932, [2019] BCC 1031.
2. The appellants’ technical-prejudice argument did not reflect the judge’s reasoning. The principles discussed in Pozzoli SpA v BDMO SA [2007] EWCA Civ 588, [2007] FSR 37, and Koninklijke Philips NV v Asustek Computer Inc [2019] EWCA Civ 2230, [2020] RPC 1, would have been engaged if the invention were prima facie obvious but the skilled team were deterred by a technical prejudice or perceived problem. The judge instead found that it was not obvious to try mirabegron as an OAB treatment with a reasonable expectation of success.
3. Conor Medsystems Inc v Angiotech Pharmaceuticals Inc [2008] UKHL 49, [2008] RPC 28, established that obviousness must be assessed by reference to the claim, not by a vague paraphrase based on the extent of disclosure. Once the patent plausibly disclosed efficacy for the claimed medical use, the amount of supporting evidence in the specification did not alter the obviousness test. No human clinical or human-tissue experiments were required.
4. The judge was entitled to find that β3-adrenoceptor agonism had potential but remained uncertain, that the disclosure in 288 gave little information about mirabegron’s activity, and that success with one agonist could not be assumed for another. The patent’s focused disclosure of mirabegron, its proposed use for OAB, and concrete assay results constituted a technical contribution on the judge’s findings. No error of law or principle was shown.

• Court of Appeal (Civil Division): In [2023] EWCA Civ 880, the appeals by Teva and Sandoz were dismissed.
• High Court of Justice, Patents Court: Meade J dismissed the revocation claims, relating to the patent and supplementary protection certificate, and granted infringement relief in [2022] EWHC 1316 (Pat).