Next week’s UK Supreme Court hearing on the long-running patent dispute over pregabalin will be watched closely by life sciences innovators.

The final ruling should help clarify the role of ‘plausibility’ in determining the sufficiency of patent applications – a currently unanswered question on which many disputes hinge. But there is some anxiety about the outcome, with a major pharma company association warning that a decision to set an unduly high threshold could undermine the ability of organisations to protect their innovations.

The hearing – which will run between next Monday and Thursday – relates to a long-standing patent dispute between Pfizer subsidiary Warner-Lambert and several generic companies, including Mylan and Actavis, over Warner-Lambert’s second medical use patent for the use of pregabalin (marketed as Lyrica) in treating pain, including neuropathic pain.

In 2015, the High Court ruled that the patent did not make it plausible that the drug would be effective in alleviating all of the types of pain for whose treatment it was granted. On that basis, its specification was deemed to be insufficiently disclosed for it to be performed by a person skilled in the art, and the patent was ruled invalid. This decision was upheld in 2016 by the Court of Appeal; but, while the IP in question expired in July 2017, Warner-Lambert is now seeking to have the previous rulings reversed by the Supreme Court.

Next week’s review will be the first time the UK Supreme Court has considered what role ‘plausibility’ – whether the effectiveness of a patented invention is made plausible in the application – ought to play in the test for sufficiency of disclosure.

What constitutes plausibility in a patent is far from clear at present, with a previous Supreme Court ruling noting that: “The dividing line between “plausibility” and “educated guess”, as against “speculation”…can be difficult to discern in terms of language and application, and is a point on which tribunals could often differ.”

This question has a significant practical bearing on UK patent law, as Andrew Wells of Herbert Smith Freehills explains: “’Plausibility” has been an increasingly hot topic in patent litigation in recent years, particularly in cases relating to pharmaceuticals, and its rise has not been without controversy among patent lawyers. It has most frequently been associated with inventive step and insufficiency, but it has also come up in relation to industrial applicability, priority and novelty, and it is now a firmly established concept for any lawyer considering the validity of a patent.”

In providing greater clarity on this point, the Supreme Court’s ruling will be welcomed by pharmaceutical companies. But depending on the nature of the judgment, it could have very different implications for rights holders.

If a high threshold for plausibility is set, life sciences patents may be more susceptible to invalidation, and innovators may have to risk filing their patents at a later stage in their long-running and costly drug development processes.

On the other hand, a low hurdle would make it easier for pharmaceutical companies to claim and defend a monopoly on treatments from an earlier stage of scientific research.

Anxieties about the potential outcomes of the hearing were expressed recently by the UK BioIndustry Association (BIA) – a group representing life sciences innovators, which has successfully applied to intervene in the case.

While welcoming the prospect of greater certainty, and not siding with any of the parties involved, the BIA’s application to intervene urged the court not to “unfairly penalis(e) biotechnology companies (by) requiring an unwarranted level of information”. It warned that onerous requirements – such as providing clinical data - could undermine the patent system’s aim of incentivising innovation by jeopardising pharma companies’ ability to protect their inventions and attract R&D investment.

BIA asked the court to bear in mind the particular difficulties faced by life sciences rights holders in choosing an optimum point to apply for IP protection during a complex and drawn-out development process. If plausibility standards are set too high, innovators would be prevented from protecting their inventions until well into the R&D process, with the risk of rivals acquiring patent rights first.