Case details

Warner-Lambert Company LLC (Appellant) v Generics (UK) Ltd t/a Mylan and another (Respondents)

Case ID: UKSC 2016/0197

Case summary

  1. Whether (and what) role plausibility should play in the statutory test for sufficiency, and whether a patent should be held insufficient for lack of plausibility even though it is in fact enabled across the full scope of the claim.
  2. If a plausibility test is appropriate, provided there is basis to support the claim across part of its scope, whether later evidence can be used to fill the gap.
  3. The correct approach to (and the use of expert evidence in) the construction of patent claims.
  4. Whether a post-trial application to amend an invalid patent claim to limit it to a part found to be plausible is an abuse of process.

The Appellant is the proprietor of a particular Swiss-form European patent, for the second medical use of pregabalin in the treatment of neuropathic pain. The Respondents applied to revoke the patent in part on the basis that the specification was insufficiently disclosed for it to be performed by a person skilled in the art. The judge’s test for sufficiency required plausibility of the efficacy of the invention across breadth of a claim. He found that the claims for use in treating pain peripheral neuropathic pain were plausible and valid, but the remaining claims were implausible and therefore invalid for insufficiency. He construed claim 3 for treating neuropathic pain as including peripheral and central neuropathic pain (the latter of which he found the invention did not plausibly treat), and was therefore invalid as only partially plausible. The Appellant’s application to amend claim 3 to limit it to peripheral neuropathic pain was held to be an abuse of process. The findings of the judge were upheld by the Court of Appeal, against whose judgment the Appellant now appeals.

Judgment appealed

[2016] EWCA Civ 1006



Warner-Lambert Company LLC

  1. Generics (UK) LTD
  2. Actavis Group PTC EHF



Lord Mance, Lord Sumption, Lord Reed, Lord Hodge, Lord Briggs

Hearing start date

12 Feb 2018

Hearing finish date

15 Feb 2018

Watch hearing
12 Feb 2018 Morning session Afternoon session
13 Feb 2018 Morning session Afternoon session
14 Feb 2018 Morning session Afternoon session
15 Feb 2018 Morning session Afternoon session