HomeInsightsSupreme Court dismisses Warner-Lambert’s appeal finding Swiss-form claims invalid for insufficiency.

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Warner-Lambert Company LLC, a company in the Pfizer Group, was the proprietor of a European Patent for Isobutylgaba for the treatment of epilepsy.  Pregabalin, a derivative of Isobutylgaba, was marketed by Warner-Lambert under the brand name “Lyrica”. The patent expired in the UK on 17 May 2013.

This appeal concerned a second European Patent, entitled “Isobutylgaba and its derivatives for the treatment of pain”, with a priority date of 24 July 1996 (the Patent).  The claims of the Patent were all purpose-limited, i.e. in the Swiss form.  Claims 1, 2 and 3 stated:

1. Use of [Pregabalin] or a pharmaceutically acceptable salt thereof for the preparation of a pharmaceutical composition for treating pain.

  1. Use according to Claim 1 wherein the pain is inflammatory pain.
  2. Use according to Claim 1 wherein the pain is neuropathic pain”.

Lyrica received a marketing authorisation in the EU for the treatment of peripheral neuropathic pain and epilepsy in July 2004 and for the treatment of central neuropathic pain in September 2006.  It was also authorised for the treatment of generalised anxiety disorder.

Generics (UK) Ltd t/a Mylan, and Actavis Group PTC EHF, marketed generic pharmaceutical products.  Actavis marketed a generic pregabalin product under the brand name “Lecaent”, launched in 2015.  In these proceedings, Mylan and Actavis claimed revocation of the Patent on the grounds of lack of inventive step and insufficiency.  Warner-Lambert claimed that Actavis had infringed Claims 1 and 3 above.

At first instance, Mr Justice Arnold rejected the arguments based on lack of inventive step.  Further, he held that Claim 1 (pain) and Claim 3 (neuropathic pain) were invalid because, although there was sufficient disclosure in the specification to support the claim that pregabalin was efficacious in the treatment of inflammatory pain and peripheral neuropathic pain, it was insufficient in relation to central neuropathic pain.  Since Claim 1 extended to all pain and Claim 3 to all neuropathic pain, including central neuropathic pain, both claims failed for insufficiency.

Arnold J also rejected as an abuse of process Warner-Lambert’s application after judgment to amend the Patent by narrowing the claims in terms which would arguably have made them valid.

On appeal, the Court of Appeal upheld Arnold J’s findings relevant to this appeal, and his decision on the amendment application.

Warner-Lambert appealed to the Supreme Court contending that all the claims of the Patent were valid.  Actavis and Mylan cross-appealed, arguing that none of the claims relating to neuropathic pain were valid.  They only accepted as valid the claims limited to inflammatory pain, for which there was no marketing authorisation.

This gave rise to four issues on appeal: (i) the construction of the claims (in particular, Claim 3 as to neuropathic pain); (ii) the sufficiency of the disclosure in the specification; (iii) amendment and abuse of process; and (iv) the test for infringement of a patent in relation to manufacture for a limited use.


The Supreme Court dismissed Warner-Lambert’s appeal and allowed Actavis’ cross-appeal.

Construction and amendment

The Supreme Court unanimously affirmed the view of both courts below that Claim 1 extended to all pain and Claim 3 to all neuropathic pain, whether peripheral or central.  It also unanimously affirmed Arnold J’s decision rejecting Warner-Lambert’s application to amend the patent so as to limit the scope of these claims.

Sufficiency and plausibility

Here, the Supreme Court held by a majority (Lord Sumption, Lord Reed and Lord Briggs) that the disclosure in the specification (based on a model of inflammatory pain in mice) supported the claims insofar as they extended to inflammatory pain, but not to any kind of neuropathic pain.  It followed that Claims 1 and 3 failed for insufficiency, and that Warner-Lambert’s appeal should be dismissed and the cross-appeal allowed.

Lord Sumption said that an invention was sufficiently disclosed only if the specification enabled it to be “performed”.  In the case of a patent for a new product or process, that assumption was almost always correct, as the skilled person would discover that it worked by replicating it in accordance with the specification.  However, the assumption was not correct in the case of a second use patent, as the invention was not the compound or the process of its manufacture, but consisted in the new purpose for which the product was to be manufactured.

Lord Sumption said that reading the law on sufficiency literally would mean that all that needed to be disclosed was the new purpose.  The skilled person would not need to know how or why the invention worked in order to replicate it.  A patent could therefore be obtained on a wholly speculative basis.  For that reason, both Arnold J and the Court of Appeal had concluded that it was not enough simply to refer to a known compound and assert that it was efficacious for treating a specified condition.  The patentee had to disclose some reason for regarding the assertion as “plausible”.

Essentially, the principle was that the specification must disclose some reason for supposing that the implied assertion of efficacy in the claim was true.  It was not enough to justify a monopoly to say that it was merely “possible” a priori that a drug that was effective for inflammatory pain would also be effective for neuropathic pain without that possibility having some scientific basis or being more than speculative.  “Everything is possible that is not impossible, but “not impossible” is very far from being an acceptable test for sufficiency”, he said.

In this case, the disclosure in the specification of the patent itself did not contribute any knowledge of the art capable of justifying a claim to a monopoly of the manufacture of pregabalin for the treatment of neuropathic pain of any kind.  Claim 3 of the patent and the other claims relating to neuropathic pain were therefore invalid for insufficiency.

Lord Hodge (dissenting) proposed an alternative approach to sufficiency, preferring a lower standard of plausibility, and would have dismissed the cross-appeal.  Lord Mance agreed with Lord Hodge, concluding that the majority’s approach imposed too high a threshold.


Here, the Supreme Court unanimously held that if Claims 1 and 3 had been valid, they would not have been infringed by Actavis.  However, the reasons for arriving at this agreed result differed substantially.

Both parties said that there had to be a mental element to infringement under s 60(1)(c) of the Patents Act 1977.  In other words, the intention of the manufacturer, or what the manufacturer was making the compound “for”, was relevant.

The difference between the parties concerned the test of intention.  Actavis said that the test was subjective: the manufacturer had to make the product with intent to target the patent-protected market.  Arnold J had accepted that submission.

Warner-Lambert’s primary case was that the test was objective: a manufacturer had to intend the foreseeable consequences of his actions.  If it could be shown that it was foreseeable to the manufacturer that a more than de minimis amount of the compound would in due course be used for the treatment of neuropathic pain, that was enough to support a case of infringement of Claim 3 under s 60(1)(c).

Lord Sumption disagreed with both parties.  “I think that a test for infringement which depended on intention, whether objective or subjective, would be contrary to principle and productive of arbitrary and absurd results”, he said.

In Lord Sumption’s opinion, in a purpose-limited or Swiss-form claim, the badge of purpose was the physical characteristics of the product as it emerged from the relevant process, including its formulation and dosage, packaging and labelling and the patient information leaflet which identified the conditions for which treatment was intended.  He called this the “outward presentation” test.

On the facts, it was not disputed that Lecaent was sold under a “skinny label”, i.e. for the treatment of some indications only, namely epilepsy and general anxiety disorder, for which patent protection had expired.  Therefore, Lord Sumption concluded, there was no infringement.  The appeal was therefore dismissed and the cross-appeal allowed.

Dissenting views

Lord Briggs noted that the case raised an important and difficult question of law, likely to be applicable to all Swiss-form patents, and that the answer to infringement may have consequences for all purpose-limited claims in future cases.  Although Swiss-form claims were now a closed class (because they have been replaced by purpose-limited product claims under article 54(5) of the European Patent Convention 2000) there were sufficient still in force for the issues as to infringement to have potentially wide-ranging consequences, he said.

Lord Briggs (and Lord Hodge) preferred the view of Arnold J that the test was whether the alleged infringer subjectively intended to target the patent-protected market.  “When we speak of someone making something “for” a particular use, and conclude as we must that “for” means something more than “suitable for”, it must point to something in the mind of the manufacturer”, Lord Briggs said.

Further, Lord Briggs said, the “packaging only” approach did not strike a fair balance and did not give adequate protection for patentees.  A generic manufacturer might covertly encourage dealers and pharmacists to use the product for the treatment of pain, regardless of what appeared on the label.  In addition, a “smoking-gun” internal document might reveal that the manufacturer’s packaging for the non-patented use was a charade and that its corporate purpose was to profit by its use for the patented indications.   These forms of evidence might prove the requisite intent, even if the packaging did not.

Finally, Lord Mance agreed that the test depended on the objective appearance and characteristics of the product as it was prepared, presented and put on the market, but considered that in rare cases the context might make it obvious that these should “not be taken at face value”.  Further, he said, in some circumstances, a generic manufacturer should perhaps go further by including a notice positively excluding the patent-protected use.  (Warner-Lambert Company LLC v Generics (UK) Ltd t/a Mylan [2018] UKSC 56 (14 November 2018) — to read the judgment in full, click here).