On 10 September Arnold J handed down the latest[1] in a series of High Court decisions concerning the Warner-Lambert Company’s patent relating to the use of pregabalin in the treatment of pain.

The decision runs to 174 pages and 727 paragraphs in length, so it is impractical to provide commentary on every aspect here. However, at the heart of the case are questions concerning the proper construction of “Swiss-style” second medical indication claims as well as their enforcement.  The decision is therefore particularly notable as it represents the first attempt by a court to apply the revised test for direct infringement of Swiss claims as set forth by Floyd LJ in previous proceedings before the Court of Appeal[2], which provided a broader test than previously applied by Arnold J in the so-called Warner-Lambert I decision[3].

Although the High Court found a number of claims invalid for insufficiency, including those which Warner-Lambert sought to assert against manufacturers of generic pregabalin, the judge nevertheless considered the question of infringement.  Despite considerable misgivings as to whether the test advocated by the Court of Appeal was indeed the correct one, and how it should be interpreted, the High Court held that even if the Swiss-style claims had been valid, they would not have been infringed. In the judgment of the court, it would not have been reasonably foreseeable to the manufacturer of the generic product that generic pregabalin would intentionally have been prescribed by doctors and/or intentionally dispensed by pharmacists for the treatment of the indication which was the subject of the Swiss-style claims.  Consequently, various communications sent by the patent owner amounted to groundless threats of infringement proceedings against parties involved in prescribing and dispensing the generic product.

The High Court’s reasoning appears to set a very high hurdle in the UK for any patent owner wishing to assert a Swiss-style second medical indication claim against an alleged infringer.  However, the facts of this particular case are unusual in that the dosage regime for pregabalin does not vary from one medical indication to another.  In other cases the dosage regime may vary depending on the condition to be treated and so, in such cases, it may be easier to prove the necessary degree of “reasonable foreseeability” to support a finding of infringement.

In view of the importance of the matters under consideration in this judgment it is highly likely that the case will return to the Court of Appeal, and probably head to the Supreme Court, before clarity is finally achieved on the correct interpretation of Swiss-style claims.

Background

Warner-Lambert, a company in the Pfizer Group, markets pregabalin under the trade name “Lyrica” for the treatment of neuropathic pain, generalised anxiety disorder (GAD) and epilepsy. Warner-Lambert owns an EP (UK) patent which includes the following “Swiss-style” claims:

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

3. Use according to Claim 1 wherein the pain is neuropathic pain.

Actavis applied for a so-called “skinny label” marketing authorisation for its own generic pregabalin product (“Lecaent”) in the treatment of epilepsy and GAD, but not neuropathic pain.

Generics UK Limited (trading as Mylan) and Actavis commenced claims for revocation of the patent in a bid to clear the way for the launch of generic pregabalin products for the treatment of neuropathic pain.

Warner-Lambert considered that even if the claims for revocation failed, Lecaent was likely to be prescribed for the treatment of neuropathic pain in view of doctors’ general prescribing practice. Warner-Lambert sought reassurance about measures taken by Actavis to ensure that Lecaent would not be prescribed for neuropathic pain, and subsequently applied for an interim injunction which would have obliged Actavis to take certain actions in this respect in view of an alleged infringement of claims 1 and 3 of the patent.

The Warner-Lambert I approach to Swiss claims

In Warner-Lambert I, reported here, Arnold J dismissed the application for an interim injunction.

Swiss claims are regarded as process claims[4].  A Swiss claim would therefore be infringed under s.60(1)(c) of the Patents Act 1977 by keeping, disposing of, or offering to dispose of a product obtained directly by means of the claimed process.

Both parties agreed that, if Actavis used pregabalin to prepare a composition “for treating (neuropathic) pain”, the resulting generic product, “Lecaent”, would be “obtained directly by means of” the claimed process and would therefore infringe claims 1 and 3.  The dispute therefore concerned the meaning of “for treating pain”.

Normally, “for” is interpreted as “suitable for”.  However, in a Swiss claim, “for” is interpreted as “suitable and intended for” treatment of the indication specified[5]. Lecaent was clearly suitable for treatment of pain.  The question was therefore what “intended for” means.  As the judge put it, “first, whose intention is relevant, and secondly, what is meant by ‘intended’?”

Referring to Actavis v Merck[6], Arnold J noted that a Swiss claim “is not aimed at and does not touch the doctor – it is directed at the manufacturer.” Similarly, the claim could not touch the pharmacist dispensing the prescribed medication. The relevant intention had to be that of the manufacturer.

Regarding the meaning of “intended”, Arnold J held at [111] that:

“the word “for” in Swiss form claims imports a requirement of subjective intention on the part of the manufacturer that the medicament or pharmaceutical composition will be used for treating the specified condition.”

According to this construction, and absent any allegation of “subjective intention”, there was no serious issue to be tried.  In view of this, and on a consideration of the balance of justice in terms of the damage to either party by the granting of an injunction, the judge refused Warner-Lambert’s application for an interim injunction.

The Court of Appeal’s approach to Swiss claims

Warner-Lambert appealed the decision not to grant an interim injunction.  The Court of Appeal dismissed Warner-Lambert’s appeal, finding that Arnold J had assessed the balance of justice correctly in view of the available facts.  Nevertheless, the Court of Appeal held a different view on the construction of Swiss claims and the question of infringement.

Floyd LJ held that:

“The skilled person would understand that the technical features of the present claim extend beyond making pregabalin, yet fall short of including the step of actually using pregabalin for treating pain. Instead it includes a feature concerned with the ultimate purpose of the product manufactured, namely the intentional treatment of pain. I would describe the subject matter of the claim, therefore, asmaking pregabalin for patients to whom it will be intentionally administered for treating pain. Making pregabalin for patients to whom it is to be administered for the non-patented indications is not within the technical subject matter of the claim. Only the former category of manufacture makes use of the technical contribution of the patentee.” [Anchor] [7]

The word “for” therefore did not require subjective intent on the part of the manufacturer that the end product would be used for treating pain.  Rather, it would suffice that the manufacturer “knows or could reasonably foresee” that some of the drug would ultimately be used for that purpose, even if the manufacturer did not have that specific intention himself.

Back to the High Court…

The full trial took place this summer, resulting in the September decision.

Although Arnold J found claims 1 and 3 invalid for insufficiency, he nevertheless considered the position regarding infringement on the assumption that the finding on insufficiency may be found incorrect.  He accepted Actavis’ argument that the infringement test advocated by the Court of Appeal was obiter and hence not binding.  Nevertheless, he considered the test persuasive and was therefore obliged to follow it unless convinced it was wrong.

Arnold J conceded that there were “powerful arguments” that the “knows or could reasonably foresee” test was wrong: arguably, this construction of “for” makes infringement depend on the mental state of the prescriber, not the manufacturer; accordingly, the manufacturer may infringe as a result of the actions of third parties outside his control. The test also seemingly had the consequence that, if it wasreasonably foreseeable to a manufacturer that some of his drug would be intentionally administered for the treatment of pain, then all acts of manufacture, and all dealing in the manufactured product, would be infringing acts regardless of the ultimate end use of the manufactured product.

Nevertheless, despite considerable doubts, Arnold J was not convinced that Floyd LJ’s test was wrong, and therefore applied this test to the question of infringement.

Counsel for Pfizer (Warner-Lambert’s parent company) argued that Floyd LJ’s interpretation of “for” amounted to a “pure test of foreseeability on the part of the manufacturer that its pregabalin would in fact be used for the treatment of pain”.  Arnold J did not accept this, instead considering (in light of the Court of Appeal’s reasoning) that the test required not just foreseeability, but also an element of intention.  He agreed with Actavis that the intention of the prescribing doctor was “highly relevant, if not exclusively so”, as it is the prescribing doctor who has the requisite medical knowledge to prescribe the drug with the intention of treating pain.  He further agreed with Actavis that it was not sufficient for a finding of infringement that the doctor intended to prescribe pregabalin from any source for the treatment of neuropathic pain; rather, the doctor must intend specifically to prescribe Lecaent for the treatment of neuropathic pain.  The intention of the dispensing pharmacist could also be relevant in instances where, knowing that the doctor had prescribed generic pregabalin for treating neuropathic pain, the pharmacist nevertheless dispensed Lecaent.  However, the intention of the patient was not relevant.

Considering the facts at various possible relevant dates, in each case Arnold J considered that it would not have been foreseeable to Actavis that Lecaent would have been intentionally administered for the treatment of neuropathic pain except in a small number of exceptional cases which were to be regarded as de minimis.  This conclusion was reached in light of Actavis’ application for a “skinny label” authorisation; the finding, based on evidence at trial, that doctors are encouraged to prescribe generics where possible and that only about 5% of prescriptions indicate the medical indication for which a prescription is made; and that both Actavis and Pfizer, as well as the NHS, had taken steps to try to prevent doctors and pharmacists from prescribing the generic product for neuropathic pain.  Accordingly, claims 1 and 3 were found not to be infringed.

Where next?

It is difficult at present to see how, in light of the “reasonably foreseeable” test as applied here, a valid second medical indication patent having “Swiss style” claims can be enforced in the UK, particularly where the alleged infringer has made efforts to minimise the risk of a generic product being prescribed for a patent-protected medical indication (e.g. by means of “skinny label” market authorisations and advice to prescribing doctors and dispensing pharmacists).  Even where such measures have not been taken, in view of the practicalities of the drug prescription regime in the UK, it may be difficult to prove “reasonable foreseeability” of the relevant intent at anything more than a de minimis level.  However, it may be easier to enforce a Swiss style claim in cases where (unlike in the present case) the dosage regime for the medical indication specified in the claim differs from that of other indications, which would make the doctor’s intention clearer.

This decision will almost inevitably be subject to appeal, and therefore patent holders and generics manufacturers alike will doubtless hope that the next stage in proceedings leads to greater clarity regarding this question of fundamental importance to the pharmaceutical industry.