The UK Supreme Court recently heard the latest instalment of an ongoing battle over the blockbuster drug pregabalin (Warner-Lambert v Actavis). The judgment is not expected to be issued until later this year. Edith Penty Geraets provides a summary of the saga to date.
The case concerns the validity and infringement of Warner-Lambert’s (Pfizer) second medical use patent, directed to the drug pregabalin for the treatment of neuropathic pain. The basic patent for the drug expired in 2014.
Pregabalin is marketed by Pfizer under the name Lyrica® for the treatment of various indications such as neuropathic pain, general anxiety disorder (GAD) and epilepsy. Actavis sells a generic pregabalin product under the name Lecaent®.
The patent claims are in the old ‘Swiss-type’ format (i.e. the use of substance X for the manufacture of a medicament to treat disease Y). This type of claim is no longer accepted by the UKIPO. However, there are many granted patents that have Swiss-type claims for which this case will be applicable.
In the initial proceedings, Actavis sought to revoke Warner-Lambert’s patent on the basis that use of pregabalin for the treatment of peripheral and central neuropathic pain had not been sufficiently disclosed in the application, and that the claims lacked inventive step. Warner-Lambert subsequently brought infringement proceedings against Actavis for the anticipated launch of its generic pregabalin product Lecaent®, to be marketed for treatment of epilepsy and GAD.
The first instance decision was held in favour of Actavis. The judge considered that only the treatment of peripheral neuropathic pain had been made plausible and thus the patent was held to be invalid. The judge also held that even if the patent had been valid, Actavis’ pregabalin product would not have infringed.
Warner-Lambert then sought to limit the claims to peripheral neuropathic pain only, but was not permitted to do so as this was considered an abuse of process. The court held that it should have submitted an intention to amend before the proceedings began.
Both parties appealed the decision.
Court of appeal
The Court of Appeal agreed that Warner-Lambert’s patent was invalid for insufficiency. It was held that the data in the patent was insufficient to render a claim covering all types of neuropathic pain plausible. Allegedly, the skilled person would understand that pregabalin would be suitable to treat peripheral neuropathic pain, but not central neuropathic pain. The Court of Appeal also upheld the High Court’s rejection of Warner-Lambert’s request to amend the claims to peripheral neuropathic pain.
Despite the finding of invalidity, the Court of Appeal provided some helpful comments on what would constitute direct and indirect infringement of second medical use Swiss-type claims. On direct infringement, the Court of Appeal commented that infringement depends on whether the manufacturer (i.e. Actavis) knows or is able to foresee that there will be intentional use of the drug for the new medical indication. Infringement could be avoided if the manufacturer takes reasonable steps to prevent the generic product being used to treat the claimed medical indication. On indirect infringement, the Court of Appeal commented that downstream acts, such as labelling performed by a pharmacist, should also be considered part of the manufacturing process when deciding whether “means for putting the invention into effect” had been provided by the manufacturer.
The decision was appealed to the UK Supreme Court. We’ll provide a full update on this highly relevant case once the UK Supreme Court issues the judgement later this year.