In an important judgement the Court of Appeal has reached its decision in the Warner-Lambert v Actavis case, concerning the issues of sufficiency, post-trial amendment and infringement in relation to second medical use claims in the ‘Swiss’ format. The judgement has important ramifications, especially for those interested in pharmaceutical patent protection in the UK.

Background to the Appeal

Warner-Lambert, through Pfizer, markets the drug pregabalin (Lyrica®) in the UK for the treatment of epilepsy, generalised anxiety disorder (GAD) and neuropathic pain. With sales by Pfizer in the UK alone of US$310 million in 2013, this is a drug of considerable importance to Warner-Lambert/Pfizer and of considerable interest to generic manufacturing companies such as Actavis.

While patent protection for pregabalin per se has expired, the present appeal concerned European Patent (UK) No. 0 934 061, drawn to a second medical use of pregabalin, specifically for the treatment of pain (claim 1) and more especially neuropathic pain (dependent claim 3). As reported in the Autumn/Winter 2015 edition of Inside IP, in a series of related decisions by the High Court of England and Wales, Actavis and others sought revocation of the patent on the grounds of a lack of inventive step and insufficiency, while Warner-Lambert counter-sued Actavis for infringement. In the main judgement of 10 September 2015, the High Court held that while none of the claims lacked an inventive step, several claims including claims 1 and 3 of the patent were invalid on the grounds of insufficiency, and that even if claims 1 and 3 had been valid Actavis would not have infringed these claims. Immediately after the trial, on 1 October 2015, Warner-Lambert sought to amend claim 3 in order to overcome the finding of insufficiency, however this was dismissed as an abuse of the process of the court.

To read the full article, please click below.