On 14 November 2018 the Supreme Court handed down its decision that Warner-Lambert's EP(UK) patent relating to the second medical use of pregabalin for the treatment of pain is invalid. This decision came in the case of Warner-Lambert vs Generics (UK) Ltd [2018] UKSC 56 where the relevant claims were also held to have not been infringed even if they were valid. However, the Justices of the Supreme Court came to this conclusion for different reasons.
Pregabalin is marketed in the UK for the treatment of epilepsy by Warner Lambert under the brand name Lyrica. An EP(UK) patent covering pregabalin expired in 2013 however, Warner-Lambert are also the proprietors of "second medical use" patent covering the use of pregabalin for the treatment of pain (EP(UK) 0934061), which is the subject of this dispute.
Patent protection can be granted in Europe and in the UK for a known drug where it is for a new indication. However, from the patent it must be at least plausible that the drug treats the new indication in order for the patent to be sufficient. In this way, a hurdle is in place to prevent purely speculative applications directed to known drugs for new indications.
In this case, claims 1 and 3 of the patent in suit are directed to the treatment of pain (in general) and neuropathic pain (whether peripheral or central), respectively. Three of the five Supreme Court Justices found that the disclosure in the specification supports the claims in relation to inflammatory pain, but not neuropathic pain, whether peripheral or central. The Supreme Court found that claims 1 and 3 therefore fail for insufficiency. Their view requires the patentee to demonstrate that the specification discloses some scientific reason why the implied assertion of efficacy in the patent claim may well be true. More than a bare assertion or mere possibility of therapeutic efficiency is required. Further, Warner-Lambert were not allowed to narrow their claim to cover the indications which they considered plausible, as such amendment was thought to be an abuse of the procedure.
Some will see this as a higher hurdle than previously applied by the UK courts, but is roughly in line with the increasing high standard that the EPO are applying to the plausibility of second medical use inventions.
The Supreme Court also considered the infringement of these claims had they been valid. Actavis markets a generic pregabalin product under the brand name "Lecaent", launched in 2015. It was not disputed that Lecaent was sold with labels and patient information to the effect that it was for the treatment of seizure disorders and general anxiety disorder. However, Warner-Lambert asserted that Lecaent was being prescribed by the NHS for pain as well, thereby infringing the patent in suit.
The five Supreme Justices all agreed that Lecaent did not infringe the second-medical use claims if they were to be found valid, but for very different reasons. Two of the Justices considered that the intention of the alleged infringer was irrelevant and that the sole criterion of infringement is whether the product, as it emerges from the manufacturing process including any labelling or accompanying leaflet, is presented as suitable for the uses which enjoy patent protection – the "outward presentation" test. Another Justice considered that the test depends on the objective appearance and characteristics of the product as it is prepared, presented and put on the market, but considers that in rare cases the context may make it obvious that these are not to be taken at face value. The two remaining Justices preferred the view of the lower court that the test is whether the alleged infringer subjectively intended to target the patent-protected market.
The Supreme Court decision provides clarity on the UK's approach to the sufficiency of second medical use claims, but unfortunately provides no clear indication of how the infringement of such claims will be considered when the alleged infringer does not outwardly target the new indication market.
Innovators of new treatments will see this decision as a further hurdle to overcome in protecting new treatments. Patent applications are often filed relatively early in the drug discovery process in order to be the first flag in the sand. An honest objective look at the information in the specification supporting each indication should be performed at all stages of the patent process. This decision will be a particular blow to Warner-Lambert as they may be liable to pay the NHS for the additional money (in the region of £500m) spent while Warner-Lambert were challenging the invalidity ruling.
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