Warner-Lambert feels the pain

What you need to know

The Supreme Court has handed down its long-awaited decision in the battle between Warner-Lambert (the patentee) and Actavis and Mylan over sales of a generic pregabalin product. There is a lot to digest in the decision, but the key points are as follows:

  1. Construction of the patent claims: The court unanimously affirmed the view of the courts below that Claim 1 of the patent extends to all pain and Claim 3 to all neuropathic pain, whether peripheral or central.
  2. Abuse of process: The court unanimously affirmed Arnold J’s decision rejecting Warner-Lambert’s application to amend the patent to limit the scope of Claim 3 as it was made too late.
  3. Claims insufficient: The court held by majority (Lords Sumption/Reed/Briggs) that the disclosure in the patent supports the claims so far as they extend to inflammatory pain but not to any kind of neuropathic pain. Claims 1 and 3 failed for insufficiency on the basis that the disclosure in the patent did not make such claims plausible across their scope.
  4. No infringement: The court (in obiter) held by majority that if Claims 1 and 3 had been valid, they would not have been infringed.

Key implications of the decision

The insufficiency decision has important ramifications for the life sciences sector. The decision has raised the plausibility threshold for sufficiency in second medical use patents to a level that requires either disclosure in the patent of supporting experimental evidence, or cogent scientific reasons as to how the product is thought to have a direct effect on a mechanism involved in the disease to be treated. This is a much higher threshold for sufficiency than had previously been envisaged. Following the reasoning of the majority on this issue, for a second medical use claim to be valid, the disclosure in the patent must make the claim plausible across its scope. The patentee must provide reasons for why it was worth trying, and these reasons must be scientifically robust such that the skilled person would expect the claimed invention to work. Whilst the dissenting judges expressed concern that this went too far and elevated the threshold for plausibility to a higher level than the previous decisions intended, it is nevertheless the ruling of the majority of the Supreme Court. It will be interesting to see how this new threshold is now applied.

The case in more detail

The patent in dispute

Pregabalin is approved for the treatment of neuropathic pain, epilepsy and generalised anxiety disorder (“GAD”). Pregabalin for the treatment of epilepsy and GAD are no longer protected by patent, however, pregabalin for the treatment of neuropathic pain is. This patent was the subject of the litigation.

The claims of Warner-Lambert’s patent are Swiss-form claims, drafted in the form: “the use of compound X in the manufacture of a medicament for the treatment of indication Y”. Claim 1 covers the use of pregabalin for the preparation of a pharmaceutical composition for treating pain and Claim 3 is for the use according to Claim 1 where the pain is neuropathic pain. It was understood at the priority date that pain can be divided into two broad categories: nociceptive pain (which includes inflammatory pain) and neuropathic pain. Furthermore, neuropathic pain can be further divided into central neuropathic pain and peripheral neuropathic pain.

The origins of the dispute

Warner-Lambert sold pregabalin (Lyrica) for use in epilepsy, GAD and pain. Actavis sold its pregabalin product (Lecaent) under a so-called “skinny-label” (ie for use for the non-patented indications of epilepsy and GAD). Mylan and Actavis sought revocation of the patent, and Warner-Lambert sued Actavis for infringement arising from use of its skinny-label product to treat pain.


One of the construction issues in the proceedings was whether the term “neuropathic pain” when used in Claim 3 encompassed both types of neuropathic pain (central and peripheral) or just peripheral neuropathic pain.
The courts below had held that the term when used in Claim 3 encompassed both types of neuropathic pain and that Claim 3 was therefore insufficient, as only the use of pregabalin to treat peripheral neuropathic pain had been found to be plausible based on the disclosure in the patent. The Supreme Court went even further and held that it was not even plausible that pregabalin could be used to treat peripheral neuropathic pain. As a result, Warner-Lambert is materially worse off following the decision, with the Supreme Court allowing Mylan and Actavis’ cross-appeals.

Application to amend

The insufficiency finding of the Supreme Court rendered Warner-Lambert’s application to amend Claim 3 moot. The Court was unanimous in upholding the abuse of process finding and reiterated that the application was made far too late – the very latest the application should have been made was when Actavis and Mylan raised their plausibility case about central neuropathic pain shortly before trial (Lord Briggs, at [120]).


Also interesting for practitioners are the obiter comments on infringement.

Indirect infringement

First - with respect to indirect infringement under s60(2) – the Court unanimously held that the invention was put into effect at the point of manufacture of the drug by the manufacturer – it did not extend to pharmacists affixing labels to products. As noted by Lord Mance at [197], 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 means of putting it into effect”.


The position is less clear as to how future cases of direct infringement under s60(1)(c) are to be approached when considering a second medical use patent, and whether the use of a skinny-label by generic manufacturers will be enough to avoid liability. The foreseeability test put forward by the Court of Appeal was rejected by the Supreme Court, and two alternatives proposed. Lords Sumption and Reed proposed an “outward presentation” test, where the intention of the manufacturer as to what its product is to be used for (ie for patented or non-patented indications) is to be limited to the intention indicated on the product itself – on its packaging, labelling or patient information leaflet. This would be an objective test and would mean that a generic manufacturer who sold its product under a skinny-label would be protected from claims of infringement (as would downstream actors such as pharmacists and doctors).

Lords Briggs, Hodge, and to a degree Mance, thought that strictly limiting evidence of the manufacturer’s intention in this way may prejudice patentees, who would be unable to bring a direct infringement claim if they had other clear evidence which showed that the generic manufacturer in fact intended its product to be sold for the patented indications, notwithstanding the skinny label. Ultimately, although the comments are obiter, it appears that in most cases, infringement will be avoided under this section if the generic manufacturer uses a skinny-label. However, if there is clear evidence that the manufacturer actually intended to sell the product for the patented purpose, the ability of the patentee to run a successful infringement claim on the back of this information has not been ruled out.


This is an important decision for the life sciences sector, particularly for patentees trying to navigate the test for sufficiency where experimental data is lacking. The decision also includes some useful guidance on the use of skinny labelling to avoid an infringement claim.

This document (and any information accessed through links in this document) is provided for information purposes only and does not constitute legal advice. Professional legal advice should be obtained before taking or refraining from any action as a result of the contents of this document.