Warner Lambert v Generics (UK) t/a Mylan [2018] UKSC 56

14 November 2018

Adrian Speck QC, alongside Pushpinder Saini QC of Blackstone Chambers and Kathryn Pickard of 11 South Square, appeared for the Respondents in Warner-Lambert’s appeal to the Supreme Court regarding their Swiss-form patent for the drug pregabalin. The appeal raised important questions concerning the role of plausibility in the test for insufficiency and the determination of infringement of Swiss-form claims.

Warner-Lambert appealed against the Court of Appeal’s ruling that certain claims of their patent for pregabalin were invalid for insufficiency. The Court of Appeal had held that the data in the patent specification, which concerned rat models of inflammatory pain such as the rat paw formalin test, did not make it plausible that pregabalin would treat central neuropathic pain effectively. However, this disclosure was found to support the claim that pregabalin was efficacious in the treatment of peripheral neuropathic pain. The Respondents cross-appealed, arguing that treatment of peripheral neuropathic pain was also insufficiently disclosed.

Warner-Lambert further appealed the lower courts’ findings on construction, as well as the ruling that post-trial amendment would constitute an abuse of process. Arguments on the appropriate test for infringement of Swiss-form claims were also raised by way of Respondent’s Notice.

The Supreme Court dismissed Warner-Lambert’s appeal and, by a majority, allowed the Respondents’ cross-appeal. The majority held that the disclosure in the patent specification supported the claims so far as they extended to inflammatory pain but not to any kind of neuropathic pain, whether central or peripheral. Claims 1 and 3 of the patent were therefore invalid for insufficiency.

Lords Sumption, Reed, Hodge and Briggs held that had the claims been valid they would not have been infringed. However their reasons for so finding differed. Lord Mance agreed with Lord Sumption’s objective appearance test but left open the possibility that in some cases this could not be taken at face value and that in other cases the manufacturer may have to include notices excluding the patented use. Lord Hodge and Lord Briggs favoured a subjective intention test.

The Supreme Court further unanimously upheld the lower courts’ findings on claim construction and amendment, holding that post-trial amendment restricting Claim 3 to peripheral neuropathic pain would amount to an abuse of process.

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