Third Strike for Warner-Lambert's Lyrica® patent
The lengthy Lyrica® patent dispute between Warner-Lambert and Mylan and Actavis is over. Last week the UK Supreme Court unanimously dismissed Warner-Lambert's appeal concerning the validity and infringement of their second medical use patent (patents covering new therapeutic uses for known active ingredients).

Background

The patent in suit is a second medical use patent for pregabalin (Lyrica®) which is indicated for epilepsy, generalised anxiety disorder and the treatment of neuropathic pain. In 2014 Mylan and Actavis brought separate claims for revocation of the patent on the basis that the specification was insufficiently disclosed for it to be performed by a person skilled in the art. Subsequently Warner-Lambert brought an infringement action in relation to Actavis' "skinny label" pregabalin product, which was authorised and marketed for non-patented indications. 

In the UK High Court Arnold J held that - Claim 1 "Use of [pregabalin] or a pharmaceutically acceptable salt thereof for the preparation of a pharmaceutical composition for treating pain" extended to all pain and dependant Claim 3 for the treatment of "neuropathic pain" would be understood broadly as including both central and peripheral neuropathic and that the patent application insufficiently disclosed pregabalin’s efficacy in treating peripheral neuropathic pain. Finally, he held that, even if the patent was valid, Actavis' "skinny label" product would not infringe the asserted claims.

Following this decision Warner-Lambert made a conditional application to amend the patent. One of the amendments sought to limit the scope of Claim 3 to peripheral neuropathic pain, and thus to exclude from its scope central neuropathic pain, which was found to be vulnerable to the insufficiency attack. Without deciding the merits of the amendment application, Arnold J held the application to amend was an abuse of the process. 

In 2015, the Court of Appeal upheld Arnold J's decision. Regarding sufficiency Lord Justice Floyd upheld Arnold's decision that Claims 1 and 3 of the patent were insufficient. It further held it was implausible that pregabalin would be effective in treating any type of pain (asserted in Claim 1) or central neuropathic pain (asserted in Claim 3) based on the data provided in the patent specification (obtained using an animal model of inflammatory pain).

Supreme Court Decision

The Supreme Court upheld the decision of both lower courts. One of the most interesting parts of the decision is the Supreme Court's views on the role of plausibility in the statutory test for insufficiency and how infringement by Swiss-style claims should be determined. 

Sufficiency

The Supreme Court held by majority that Claim 1 and Claim 3 failed for insufficiency because the disclosure in the specification supported the claims in relation to inflammatory pain, but not neuropathic pain. In so doing it not only dismissed Warner-Lambert's appeal that the claim to the use of pregabalin for the treatment of central neuropathic pain was sufficiently disclosed, it also upheld Actavis’ and Mylan's cross-appeal that the treatment of peripheral neuropathic pain was insufficiently disclosed. Similarly, the Supreme Court concluded that the animal models used to provide the data in the specification were only relevant to inflammatory pain.

Infringement

The Supreme Court unanimously held that if Claim 1 and Claim 3 had been valid, they would not have been infringed. The Judges' reasoning differed on the test to be applied with Lord Sumption and Lord Reed holding that the intention of the alleged infringer is irrelevant and preferring the "Outward Presentation Test". While agreeing in principle with this test Lord Mance added that in some cases the objective of the product appearance should not to be taken at face value. Lord Briggs and Lord Hodge preferred the view of Arnold J in the main hearing that the test is whether the alleged infringer subjectively intended to target the patent-protected market.   It is worth noting that whilst the Supreme Court's views as to the correct test for infringement is noteworthy it is obiter

The Supreme Court also rejected Warner-Lambert's indirect infringement claim on the basis that the prescription, dispensing or use of generic pregabalin to treat neuropathic pain does not “put into effect” the patented invention, or involve any supply to doctors, pharmacists or others of the means of putting it into effect. Lord Mance summarised the Court's position -"the patented invention is, under English law, the process completed by manufacture of the composition for the patent-protected use. Any subsequent use is not itself patented".

Key Considerations for the pharmaceutical sector

This decision is likely to have far reaching implications for the pharmaceutical sector. The UK Supreme Court has heightened the plausibility threshold for sufficiency in second medical use patents to the point that patentees must provide supporting experimental evidence or robust scientific reasons as to how the product is thought to have a direct effect on a mechanism involved in whatever disease is to be treated. This higher threshold is likely to make second medical use patents harder to obtain and easier to undermine.

Contributed by Charleen O'Keeffe & Florence Meagher

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