Astellas has successfully defended one of its U.K. patents against two generic drug manufacturers in a high-stakes courtroom battle over a treatment for overactive bladder syndrome. Despite this, Astellas could not convince the judge that its competitor's product would infringe on its intellectual property.

In a comprehensive 102-page ruling, Judge Rachel Mellor, at the High Court, dismissed the arguments put forward by the defendants, Sandoz AG and Teva Pharmaceuticals, who contended that the patent for mirabegron, a specific compound, was invalid due to being obvious and failing to offer enough information for replication.

Teva had previously admitted that an earlier version of its generic product infringed the patent but did not introduce arguments concerning a new version in time for the trial. However, Astellas' infringement claims against Sandoz, a Swiss company, fell short of convincing the judge.

Judge Mellor found a lack of evidence regarding whether Sandoz's medication reduced the impact of food on the drug's absorption rate, a crucial element of Astellas' patent, which had been a subject of intense debate.

"Plausibility is a different standard to that required to prove infringement, and I have held that, to prove infringement, at least some reduction in food effect must be demonstrated … Astellas did not attempt to establish this, either directly or by inference via expert evidence," Judge Mellor explained.

It's known that food can influence the absorption of mirabegron, potentially diminishing its effectiveness. The judgment stated that Astellas aimed to create a product that allowed unrestricted food intake, a commercially sound strategy, as it's undesirable for a drug to require specific food consumption instructions.

Astellas resolved this issue by slowing down the drug's absorption rate, extending it beyond the conventional four hours to a maximum of seven hours, as detailed in the judgment.

The judge ultimately determined the validity of Astellas' patent based on her interpretation of a disputed phrase in the patent claim. The phrase "pharmaceutical composition for modified release" was seen as making a "promise" to reduce food's effects, even if it didn't explicitly state so, according to the judge.

Astellas had argued that the phrase didn't necessitate demonstrating that the medication reduced food's impact on absorption. However, the judge concluded that it did require at least "some" reduction. Hence, Astellas' invention was not considered obvious, making it unlikely that other scientists aiming to diminish food's impact on similar medications would have arrived at the same product.

Judge Mellor's rationale was that, even if undergraduate students could have theoretically worked on such a project part-time for a few weeks, there were only three identifiable routes to success, all of which would likely have led to abandonment by students or research teams.

The first route was flawed as it relied purely on hindsight. The second demanded "significant imagination" and the unlikely rejection of a vital piece of information. The third route would have forced any researcher to deviate entirely from conventional practice, which was deemed improbable.

However, Judge Mellor conceded that the patent would be invalidated if her interpretation of the phrase was incorrect.

The tribunal explored evidence provided by an expert, indicating that researchers would have likely developed around 20 similar formulations based on different drugs available in the market, reducing the effects of food. Some of these would fall within a broader interpretation of the patent claim.

This victory marks Astellas' successful defense in a series of allegations previously brought by the two generic drug manufacturers. An appeals court had previously upheld its patent for the same medication in July, acknowledging its "technical contribution" to the field.

As of now, neither Astellas, Teva, nor Sandoz have commented on the verdict.

The patent in question is European Patent EP (UK) 2,345,410.

Astellas is represented by Thomas Mitcheson KC of Three New Square and Anna Edwards-Stewart of 11 South Square, instructed by Hogan Lovells.

Teva is represented by Charlotte May KC of 8 New Square and Katherine Moggridge of Three New Square, instructed by Pinsent Masons LLP.

Sandoz is represented by Charlotte May KC of 8 New Square and Joe Delaney of Three New Square, instructed by Pinsent Masons LLP.

The case is Astellas Pharma Industries Ltd. v. Teva Pharmaceutical Industries Ltd., Teva U.K. Ltd., Sandoz A.G., and Sandoz Ltd., case number HP-2021-000014, in the Chancery Division of the High Court of Justice of England and Wales.