The Pregabalin Appeal: Generics v Warner Lambert

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Generics (UK) Ltd (t/a Mylan) v Warner-Lambert Company LLC [2016] EWCA Civ 1006 (13 Oct 2016)

This was an appeal against two of Mr Justice Arnold's judgments. The first was his decision in Generics (UK) Ltd (t/a Mylan) v Warner-Lambert Company LLC [2015] EWHC 2548 (Pat) which I discussed in The Pregabalin Trial: Generics (UK) Ltd v Warner-Lambert Company LLC 18 Sept 2015. The second was his refusal to allow Warner-Lambert to amend certain claims of its patent after trial in  Generics (UK) Ltd (t/a Mylan) v Warner-Lambert Company LLC [2015] EWHC 3370 (Pat) on the ground that the application was an abuse of the process of the court.

The Issues
Lord Justice Floyd, who delivered the lead judgment on the appeal, identified the issues before the Court of Appeal as follows in the first paragraph of his judgment:

"Firstly, did Arnold J correctly hold certain claims of the patent in suit invalid for insufficiency; and, if so, should he have held more claims invalid on that ground? Secondly, was he correct in holding the patentee's application to amend claim 3 of the patent, made after judgment on the issue of invalidity, to be an abuse of the process of the court? Thirdly, if there were any valid claims which were the subject of the allegation of infringement, was the judge correct to hold that there was no infringement of the (Swiss-form, second medical use) claims in the patent?"

In the first of those judgments, Mr Justice Arnold had held that none of the claims of the patent in suit was obvious over any of the prior art relied on but several of the claims were invalid on grounds of insufficiency. Even if those claims had been valid, they would not have been infringed under s.60 (1) (c) or (2) of the Patents Act 1977. Consequently, as a result of certain letters sent out by Warner-Lambert, Pfizer was liable for making groundless threats of patent infringement proceedings.

The Facts
Warner-Lambert Company LLC ("Warner-Lambert"), now a subsidiary of Pfizer Inc ("Pfizer"), owns European Patent (UK)  0 934 061. Although the patent's title is "Isobutyl GABA and its derivatives for the treatment of pain", the relevant derivative is pregabalin, to which the Swiss-style, second medical use claims are limited. Warner-Lambert markets pregabalin under its trade mark Lyrica for the treatment of neuropathic pain, as well as for its previously known indications of general anxiety disorder ("GAD") and epilepsy. Pfizer markets the drug in the UK through its British subsidiary Pfizer Ltd. Lyrica is one of the Pfizer's most successful products. Global sales of the product amounted to approximately $4.6 billion in 2013 of which UK sales contributed approximately $310 million. Naturally, generic manufacturers want to break into the markets for the treatment of GAD and epilepsy and neuropathic pain.

The Litigation
Generics (UK) Ltd, trading as Mylan ("Mylan"), and Actavis Group PTC EHF brought separate claims for revocation of the patent on 24 June and 12 Sept 2014 respectively on the grounds of lack of inventive step and insufficiency. On 8 Dec 2014 Warner-Lambert commenced a claim for infringement of the patent against Actavis PTC, Actavis UK Ltd and Caduceus Pharma Ltd ("Actavis"), Warner-Lambert applied for an interim injunction to restrain sales of Actavis' generic pregabalin product, which was called Lecaent. The application came on before Mr Justice Arnold, who dismissed it in Warner-Lambert Company, LLC v Actavis Group Ptc EHF and Others [2015] EWHC 72 (Pat) (21 Jan 2015). I wrote about that judgment in Swiss Style Claims: Warner Lambert v Actavis 28 Jan 2015.

Actavis then made an application to strike out Warner-Lambert's claim for infringement. The application also came before Mr Justice Arnold J, who granted it insofar as the action was brought under s.60 (2) but not under s.60 (1) (c) of the Act because the correct scope to be afforded to Swiss style second medical use claims was a developing area of patent law. On 28 May 2015 the Court of Appeal dismissed Warner-Lambert's appeal against the refusal of the interim injunction but allowed an appeal against the striking out of the claim under s.60 (2). In so doing the learned Lord Justices held that Warner-Lambert's case under both subsections of s.60 was arguable.

The actions and counterclaims for groundless threats came on for trial before Mr Justice Arnold who delivered the first of the judgments mentioned above. His lordship gave both sides permission to appeal.

On 1 Oct 2015 Warner-Lambert made a conditional application to amend claim 3 of the patent by adding  the words "caused by injury or infection of peripheral sensory nerves" to the claim to the use of pregabalin to treat neuropathic pain,  The amendment was opposed by Mylan and Actavis in Generics (UK) Ltd (t/a Mylan) v Warner-Lambert Company LLC [2015] EWHC 3370 (Pat) (25 Nov 2015)  on the ground that that application was an abuse of process and Mr Justice Arnold agreed with them,

The Appeal

Warner-Lambert appealed against Mr Justice Arnold's finding on insufficiency and abuse of process and his dismissal of the counterclaim for infringement. The Court of Appeal dealt with each of the issues that Lord Justice Floyd had identified in para [1] of his judgment in turn.

Insufficiency

S.72 (1) (c) of the Patents Act 1977 gives the court power to revoke a patent if "the specification of the patent does not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art." The reason for this provision is that s.14 (3) requires every specification to

"disclose the invention in a manner which is clear enough and complete enough for the invention to be performed by a person skilled in the art."

That requirement is the heart of the bargain that an inventor makes with a state. In exchange for teaching those with the necessary skills and knowledge how to make or use the invention, the state offers the inventor a monopoly of the invention for up to 20 years from his or her patent application.

Citing paras 100 and 101 of Lord Justice Kitchin's judgment in Regeneron Pharmaceuticals Inc. and another v Genentech Inc. [2013] EWCA Civ 93, [2013] RPC 28, Lord Justice Floyd noted that a patent may be bad for insufficiency not only where the directions in the specification are inadequate to enable the skilled addressee to perform the invention at all but also where a claim is excessively broad having regard to the patentee's contribution to the art. At para [100] of his judgment in Regeneron, Lord Justice Kitchin had said  that it must

"be possible to make a reasonable prediction the invention will work with substantially everything falling within the scope of the claim or, put another way, the assertion that the invention will work across the scope of the claim must be plausible or credible."

In the appeal before him, Lord Justice Floyd considered what was meant by the requirement that the specification should make the invention plausible or credible.

After reviewing  T 0609/02 Salk Institute for Biological Studies and T 1329/04 Johns Hopkins University School of Medicine where that point had arisen before the European Patent Office Boards of Appeal Lord Justice Floyd concluded at para [19] of his judgment:

"i) A mere assertion that compound X is suitable for treating disease Y is not sufficient without any more to render the invention plausible: Salk [9];
ii) The disclosure of the patent specification does not have to be definitely predictive of the efficacy of the invention: in vitro tests which may well not be reproducible in humans or animals may suffice: Salk [10], [11];
iii) An example of adequate support to amount to a plausible disclosure would be experimental tests, showing that the claimed compound has a direct effect on a metabolic mechanism specifically involved in the disease: Salk [9];
iv) Later published data are not admissible if they alone render the invention plausible: Salk [9], Johns Hopkins [12];
v) Ultimately the purpose of the requirement of sufficiency is to place the reader in possession of the invention without imposing undue burden on him by way of further investigation or research: Salk [10]."

His Lordship also considered the Supreme Court' decision in  Human Genome Sciences Inc v Eli Lilly & Co.  [2012] 1 All ER 1154, [2012] RPC 6, [2011] UKSC 51, [2012] Bus LR D37 and the House of Lords' in Conor Medsystems Inc v Angiotech Pharmaceuticals Inc [2008] UKHL 49, [2008] RPC 28 which were broadly consistent with his conclusions even though those cases addressed different issues.

In order to determine whether a specification discloses the invention in a manner which is clear enough and complete enough for the invention to be performed by a person skilled in the art it is  necessary to construe the relevant claims, identify the person or persons skilled in the art to whom the specification is addressed and their common general knowledge. I discussed how the trial judge had approached those issues and reached his decision in my Pregabalin trial case note.

On appeal Warner-Lambert maintained the arguments that Mr Justice Arnold had rejected on the construction of the contentious claims arguing that if it was correct on those issues, the claims were plausible substantially across their breadth. Secondly, it submitted that the claims were plausible substantially across their breadth even on the construction arrived at by the judge. Thirdly it contended that the claims were plausible because pregabalin was shown to be anti-hyperalgesic.

Mylan and Actavis, submitted that the judge was right on the issues of construction and thus right to reject the argument that the claims were plausible substantially across their breadth. They also submitted that the judge had been wrong to find that the claims which were limited to types of peripheral neuropathic pain, claims 10, 11 and 12, were plausible.

The Court of Appeal rejected Warner-Lambert's criticism of the trial judge's findings on the skilled addressees' common general knowledge and his construction of the claims in contention. Finding themselves in substantial agreement with the court below their lordships rejected Warner Lambert's appeal on insufficiency.

Abuse of Process
Actavis and Mylan objected to the application to amend the  patent on the ground that it was an abuse of the process of the court, When the application came before him Mr Justice Arnold dismissed it on the ground that the application to amend  could and should have been made before trial.

In reaching his decision Mr Justiice Arnold considered the decisions of the Court of Appeal in  Nikken Kosakusho Works and another v Pioneer Trading Company and another [2006] FSR 4, [2005] EWCA Civ 906 and Nokia GmbH v IPCOM GmbH & Co KG [2011] FSR 15, [2011] Bus LR 1488, [2011] EWCA Civ 6. In thse cases Lord Justice Jacob had explored the circumstances when a c an amendment of a patent might be allowed, He said in Nikken:

"There are different situations in which the exercise of the discretion to allow amendment of a patent may be sought: (a) before a trial; (b) after trial, at which certain claims have been held valid but other claims held invalid, the patentee simply wishing to delete the invalid claims (I would include here also the case where the patentee wishes to re-write the claims so as to exclude various dependencies as in Hallen v Brabantia [1990] FSR 134. There the patentee is in effect continuing to claim which he had claimed before but in a much smaller way); and (c) after a trial in which all claims have been held invalid but the patentee wishes to insert what he hopes are validating amendments."

Lord Justice Jacob said that the court would usually allow amendment in the first two situations but not in the third in the absence of a good reason for doing so.

Lord Justice Floyd explained at para [174] of his judgment:

"The reason why the jurisprudence views with hostility the rewriting of claims after judgment is that, in contrast to the case where the claim existed in some form in the unamended patent, the party attacking the patent has not had a proper opportunity during the trial to address that claim. A further trial is thus rendered necessary in order to avoid procedural unfairness to that party, and it is the imposition of that further trial which is regarded as undue harassment."

He concluded at that that the amendment sought would, if granted, enable Warner-Lambert to bring fresh proceedings for the infringement of the amended patent on grounds that had not been raised at trial and that would be procedurally unfair. In the absence of a good reason for not seeking an amendment before trial Lord Justice Floyd could see no ground for interfering with Mr Justice Arnold's decision,

Infringement
Having held that the claims of the patent upon which Warner-Lambert relied were invalid and that those claims should not be amended, the appeal on infringement failed.

Swiss Style Claims
Although not strictly an issue in the appeal the Lord Justices considered the arguments that had been made on infringement in relation to Swiss style claims. As Lord Justice Floyd observed at para [187]:

"The law is struggling on the one hand to give the patentee a proper reward for his contribution to the art by elucidating the new use for the drug, whilst at the same time not excluding the competing manufacturer from making and marketing the drug for its known purpose. The issue is complicated by the interaction with the law relating to, and the practices of the market in, prescription medicines. The solution adopted by this court in [its decision of the interlocutory issues] was an attempt to strike the right balance by not placing insuperable obstacles in the path of the patentee, whilst at the same time recognising in very clear terms that the remedies available for infringement will have to be moulded so as to achieve fair and proportionate relief tailored to the very special circumstances of this type of case."

He therefore considered the following matters:

"Firstly, it is right that I should take a further look at the law on the construction of second medical use claims in Swiss form in the light of Arnold J's reservations and the further developments in the law of other states and the EPO. Secondly, I propose to deal with the arguments addressed to us by the intervener, the Secretary of State for Health, who was not called upon in [the interim issues appeal] and who has served a respondent's notice on the issue of the proper interpretation of Swiss-form claims. Thirdly, I propose to address Warner-Lambert's complaint that the judge failed correctly to apply the law as stated in [the previous appeal]. Fourthly, I will say something about indirect infringement."

After reviewing decisions on Swiss style claims in other EU member states Lord Justice Floyd endorsed the approach of the Court of Appeal in its earlier decision in this case notwithstanding Mr Justice Arnold's misgivings in the court below.

The Secretary of State had submitted that "as a general principle, the law does not impose liability as an accessory on the basis of a mental element which is less demanding than that of the person primarily responsible" and referred to the decision of the Supreme Court in Fish & Fish v Sea Shepherd UK and others [2015] UKSC 10 with regard to joint tort feasance at pars [37] to [44]. His lordship rejected that submission on the ground that the policy considerations in that case were different. S.60 (2) of the Patents Act 1977 provided a complete code for the issues in hand.

As to the third point, Lord Justice Floyd opined at para [216] that Mr Justice Arnold fell into error in his application of the Court of Appeal's judgment. He explained:

"Because claims in this form rely for their novelty on the purpose of the use of the drug, it is only essential that the manufacturer is able to foresee that there will be intentional use for the new medical indication. Intentional use is to be distinguished from use where the drug is prescribed for a different indication and, without it in any sense being the intention of the treatment, a pain condition is in fact treated."

On the fourth point, the learned Lord Justice considered that the prescription of a generic drug for a second medical use or its packaging for that purpose could amount to infringing acts.

Decision
Lord Justice Kitchin and Lord Justice Patten delivered concurring judgments.

Conclusion
This is an important case on insufficiency and abuse of process but it does not take the law on the infringement of a patent for a second medical use of an existing preparation much further. The Court of Appeal affirmed its earlier decision in the appeal on the interlocutory issues but that was never intended to be a final decision of the substantive ones.

Should anyone wish to discuss this case or any of the issues that arose in it, he or she should not hesitate to call me on 020 7404 5252 during office hours or send me a message through my contact form.