The Supreme Court has recently published its decision in the case of Warner-Lambert Company LLC v Generics (UK) Ltd t/a Mylan and another which considers sufficiency and infringement of second medical use claims (in Swiss-form) and the approach to post-trial amendment of patents.

The case concerned Warner-Lambert’s prescription-only drug pregabalin which was licenced for use in the EU for epilepsy, generalised anxiety disorder (GAD) and for peripheral and central neuropathic pain. Warner-Lambert had two patents, the first directed to pregabalin in relation to epilepsy and anxiety disorder which had expired in the UK on 17 May 2013 and the second (the Patent) covering the second medical use of pregablin for the treatment of pain and, in particular, neuropathic pain.

Initially, generic manufacturers, Mylan and Actavis, had sought revocation of the Patent for insufficiency of disclosure. Actavis had also applied for a licence to market pregabalin for epilepsy and anxiety disorder. Warner-Lambert sued under the Patent for infringement and indirect infringement on the basis that off label use of the generic product for neuropathic pain was likely and foreseeable.

The High Court found there was no infringement case to answer and that indirect infringement also failed because it had not been shown that there was intention to supply pregablin for neuropathic pain. The High Court also found that the claims were insufficient across their whole scope as while the treatment of peripheral neuropathic pain was plausible and valid, treatment of central neuropathic pain did not pass the plausibility test. Post-trial amendment to peripheral neuropathic pain was not allowed as it would amount to an abuse of procedure.

The Court of Appeal agreed that the Patent was invalid and could not be amended. However, in obiter, the Court of Appeal disagreed that subjective intent was required for indirect infringement and found that it was enough that a manufacturer could reasonably know or foresee how a product would be used to find that the infringing act had occurred.

The Supreme Court was asked to consider the construction of the phrase ‘neuropathic pain’, sufficiency of disclosure with respect to plausibility and central neuropathic pain, amendment and abuse of procedure and the test for infringement for second medical use claims.

At the Supreme Court, it was unanimously upheld that the view of both the High Court and the Court of Appeal was correct in that the phrase ‘neuropathic pain’ should be construed as extending to both peripheral and central neuropathic pain. This is an important aspect of the decision as ultimately it was found that the use of pregabalin to treat neuropathic pain in this broader sense was invalid for insufficiency. In particular, the court held by a majority that the specification supported inflammatory pain but not all kinds of neuropathic pain. In reaching this conclusion, the court considered plausibility in relation to sufficiency in detail and expressed some interesting and diverging views on where the threshold for plausibility should be set. There were different views on whether the treatment of peripheral neuropathic pain was plausible. Lords Sumption, Rees and Briggs found that plausibility for the effective treatment of neuropathic pain of any kind from inflammatory pain would only be suggested to the skilled person if the application as filed suggested some unifying principle. The application as filed did not mention the theory relied upon to link neuropathic and inflammatory pain, and it was not enough that this principle could be discerned from the common general knowledge. In contrast, Lords Mance and Hodge believed that there was enough disclosure in the application as filed interpreted in light of the common general knowledge to make it plausible that pregabalin would be effective to treat peripheral neuropathic pain. They believed the plausibility threshold should be set lower so that a prima facie case of therapeutic efficacy was not necessary.

The decision to reject Warner-Lambert’s application to amend the patent to limit the claims was correct was also unanimously approved. Lord Briggs confirmed that the occasion to consider whether to make an amendment had passed and should have occurred, at the very latest, when Mylan and Actavis raised their plausibility attack on central neuropathic pain shortly before trial. It was also noted that the application to amend could have been made conditional on the claims being found invalid.

In obiter, the court found that if the claims had been found to be valid, they would not have been infringed although the reasons for this conclusion given by the Lords differed significantly. Lords Sumption and Reed concluded that the intention of the alleged infringer was not relevant and that the only matter to be considered was the presentation of the product as it emerged from the manufacturing process, including any labelling or accompanying leaflet (the ‘objective appearance’ test). Lord Mance agreed that the objective appearance of the product was key but left open the possibility that in rare cases additional factors might come into play. Lords Hodge and Briggs favoured Arnold J’s test of subjective intention i.e. did the alleged infringer subjectively intend to target the patent-protected market?

The significance of this case with respect to sufficiency and infringement of Swiss type second medical use claims cannot be underestimated. With the Lords expressing different opinions on the test for indirect infringement and the plausibility threshold, this is a case that requires serious analysis and which will have wide reaching implications for second medical use patent protection. We will be providing further commentary on these matters shortly.

The full decision can be found here: https://www.supremecourt.uk/cases/uksc-2016-0197.html. If you would like any further information, please contact Hazel Robson (hrobson@secerna.co.uk)