Teva Pharmaceutical Industries Limited & Anor. v Astellas Pharma Inc

Obviousness is assessed against the claimed invention and the facts of the particular case. The existence of several possible research avenues may be relevant, but another obvious route does not make an otherwise obvious route non-obvious. The court must consider the number and extent of the avenues, the effort involved and the expectation of success.

A patentee cannot rely on a problem deterring the skilled person if the patent does not address or solve it. Where the art contains several competing therapeutic approaches, uncertain evidence and no reliable basis for predicting that any compound within a class will succeed, identifying a particular compound for a new therapeutic use may involve an inventive step.

Teva Pharmaceutical Industries Limited and Sandoz AG sought revocation of European Patent (UK) 1 559 427 B1, owned by Astellas Pharma Inc. The Patent concerned mirabegron, a β3-adrenoceptor agonist used to treat overactive bladder.

The challenges were confined to obviousness over Australian Patent Application AU 199889288 B2, common general knowledge, and an insufficiency squeeze. Astellas counterclaimed for infringement, which was admitted if the Patent was valid. The central issue was whether it was obvious at the priority date to select mirabegron from the prior art and use it to treat overactive bladder.

1. The Patent was valid. The obviousness attack over AU 199889288 B2 and the insufficiency squeeze both failed. The proposed acts would infringe if undertaken.
2. Obviousness had to be assessed by reference to the claims, applying the Pozzoli analysis and the principles endorsed in Actavis v ICOS [2019] UKSC. The court considered the motive to solve the problem, the available research avenues, the effort required and the expectation of success.
3. The skilled team was concerned with new or improved pharmacological treatments for overactive bladder generally, rather than β3-adrenoceptor agonists alone. The notional team is assessed by its overall skill-set; the precise distribution of skills and the existence of a team leader were not material.
4. β3-adrenoceptor agonism had momentum and therapeutic potential, but the skilled team would have regarded its clinical prospects as uncertain. Several mechanisms were being investigated, none was the clear favourite, and experience with agonists showed that activity in one assay did not reliably predict activity in detrusor tissue or clinical efficacy.
5. The prior art disclosed mirabegron among six compounds, but did not identify its potency, affinity or efficacy for overactive bladder. It did not provide a sound basis for assuming that all six compounds, or mirabegron in particular, would work. The omission of overactive bladder from the prior art was relevant but not decisive in isolation.
6. The concern that β3-adrenoceptor agonism might cause urine retention had been addressed by the common general knowledge and therefore did not assist Astellas. That finding did not itself establish obviousness.
7. The insufficiency argument improperly relied on the absence of human clinical or selectivity data. Unlike the prior art, the Patent focused on mirabegron, taught its use for overactive bladder and disclosed concrete results from identified assays. The insufficiency allegation was rejected.

First-instance decision of the High Court (Patents Court). No appellate history was stated in the judgment.