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

A Swiss-form second medical use claim is sufficient only if the specification, read with common general knowledge at the priority date, discloses reasonable scientific grounds for expecting the claimed therapeutic effect. A bare assertion, abstract possibility or invitation to conduct further research does not suffice. The disclosure must support substantially everything within the claim's scope, and later evidence cannot supply an absent technical contribution.

Patent claims are construed as the skilled person would understand them, balancing fair protection with legal certainty. A presumed validating construction cannot create ambiguity or rescue an otherwise clear claim. National procedural law may prevent a patentee from advancing, after judgment, an amendment which could have been sought before trial and would require a further trial.

Warner-Lambert Company LLC v Generics (UK) Ltd t/a Mylan and another concerned a Swiss-form patent claiming the use of pregabalin in manufacturing a pharmaceutical composition for treating pain, including neuropathic pain. Mylan and Actavis sought revocation for insufficiency. Warner-Lambert alleged infringement by Actavis's generic pregabalin product, which was marketed for non-patented indications under a skinny label.

Arnold J held that Claims 1 and 3 covered all pain and all neuropathic pain respectively. He found them insufficient because the specification supported inflammatory pain and peripheral neuropathic pain, but not central neuropathic pain. He also rejected a post-judgment application to amend Claim 3 and held that the claims, if valid, would not have been infringed: [2015] EWHC 2548 (Pat); [2015] EWHC 3370 (Pat).

The Court of Appeal substantially affirmed those decisions, but held that the judge had applied the wrong test for direct infringement and declined to determine infringement: [2016] EWCA Civ 1006. The Supreme Court addressed construction, sufficiency, amendment and the appropriate tests for direct and indirect infringement of Swiss-form claims.

1. Disposition. Warner-Lambert's appeal was dismissed. The cross-appeals of Actavis and Mylan were allowed by a majority comprising Lord Sumption, Lord Reed and Lord Briggs. Claims 1 and 3, and the other relevant claims concerning neuropathic pain, were invalid for insufficiency. Lord Mance and Lord Hodge would have dismissed the cross-appeals and preserved the claims confined to peripheral neuropathic pain.

2. Construction. The court unanimously held that Claim 1 extended to all pain and Claim 3 to all neuropathic pain, whether peripheral or central. Per Lord Briggs, whose construction was accepted by the other members of the court, the claims had to be understood as the skilled team would read them in the context of the patent and common general knowledge. The Protocol to article 69 required fair protection for the proprietor and reasonable legal certainty for third parties. A presumed validating construction could not create an ambiguity or override the clear breadth of Claim 3.

3. Sufficiency. Per Lord Sumption, with Lord Reed and Lord Briggs agreeing, a Swiss-form claim contains an implied assertion that the product is efficacious for the designated therapeutic purpose. The specification must disclose reasonable scientific grounds which would give the skilled person a reasonable prospect of expecting that assertion to be true. A bare assertion, a mere possibility or the fact that further testing would be worthwhile is insufficient. The disclosed basis must support substantially everything within the claim. Later evidence may confirm or refute an already plausible assertion, but it cannot replace an absent disclosure at the priority date.

   The patent's animal-model data supported inflammatory pain only. It disclosed neither data nor a scientific theory linking pregabalin to a mechanism capable of supporting efficacy for peripheral or central neuropathic pain. Common knowledge that central sensitisation was involved in inflammatory and peripheral neuropathic pain supplied no reason to think pregabalin affected that mechanism. Lord Mance and Lord Hodge preferred a lower plausibility threshold and considered the disclosure sufficient for peripheral neuropathic pain.

4. Amendment. The court unanimously upheld the refusal to amend Claim 3 after judgment. Article 138(3) of the Convention requires contracting states to permit amendment but leaves national procedural rules applicable. The proposed amendment could have been advanced before trial, raised new validity issues requiring another trial, and was properly treated as an abuse of process.

5. Infringement, obiter. All members rejected both unqualified foreseeability and the Court of Appeal's reasonable-steps qualification as tests for direct infringement under section 60(1)(c) of the Patents Act 1977. Lord Sumption and Lord Reed favoured an objective outward-presentation test. Lord Mance also focused on the product as prepared, presented and marketed, while reserving exceptional circumstances. Lord Briggs and Lord Hodge preferred proof of the manufacturer's subjective intention to target the protected market. On every approach, Actavis would not have infringed. The court unanimously concluded that section 60(2) did not apply because the patented invention was the manufacturing process, completed before prescribing or dispensing.

1. United Kingdom Supreme Court: Warner-Lambert's appeal was dismissed and the cross-appeals were allowed by a majority on insufficiency. The decisions on construction and refusal of amendment were affirmed unanimously: [2018] UKSC 56.
2. Court of Appeal: The court upheld the findings of invalidity and abuse of process. It held that the trial judge had applied the wrong test for direct infringement but did not determine infringement: [2016] EWCA Civ 1006.
3. High Court, Patents Court: Arnold J held Claims 1 and 3 invalid for insufficiency and found that they would not have been infringed: [2015] EWHC 2548 (Pat). He subsequently refused the proposed amendment as an abuse of process: [2015] EWHC 3370 (Pat).