Second medical use claims – what is the nature of the “mental element” required for infringement of a Swiss form claim?

Actavis Group PTC EHF and Others v Warner-Lambert Company, LLC and Others [2015] EWHC 2548 (Pat)


This dispute, which concerns the alleged infringement by Actavis of Warner-Lambert’s second medical use patent, will be familiar to readers, as we have reported on aspects of the litigation in the previous two issues of IP Forum (accessible here and here). Both Arnold J, in an application brought by Warner-Lambert for an interim injunction, and the Court of Appeal in Warner-Lambert’s subsequent appeal, had to grapple with difficult and novel questions regarding the construction of Swiss-form claims (i.e. claims in the form: “the use of compound X for the preparation of a medicament for treating indication Y”) and the approach to determining when such claims are infringed. Arnold J has now considered these issues once again in a comprehensive 174-page judgment following the trial of infringement, in which Actavis was ultimately found not to have infringed.

This article focuses only on the key points arising from the decision on infringement. However, for the sake of completeness, we note here that, following a challenge brought jointly by Mylan and Actavis, Arnold J held the relevant claims of the patent to be invalid in any event, on the grounds of insufficiency, and, further, found Warner-Lambert and Pfizer liable for making groundless threats of patent infringement proceedings.


Pregabalin is a drug that is used in the treatment of epilepsy, generalised anxiety disorder and neuropathic pain. There is no longer any patent protection for the medicament itself, but Warner Lambert holds a second medical use patent with claims in the Swiss form, directed to the use of pregabalin for the preparation of a medicament for treating neuropathic pain.

Actavis launched its own generic pregabalin product under the brand name Lecaent, and sought to avoid infringement by obtaining a marketing authorisation with a so-called ‘skinny label’, which carves out the indication of neuropathic pain. Warner-Lambert alleged that this infringed its patent on the basis that, notwithstanding the skinny label, Lecaent would inevitably be dispensed to patients who have been prescribed pregabalin for the patented indication. This is because, in the UK, the vast majority of prescriptions are written using the international non-proprietary name (INN) of a drug, rather than the brand name, and do not disclose the indication for which the drug has been prescribed, and further pharmacists are generally financially incentivised to dispense the generic version of a drug when presented with a prescription specifying the INN.

Summary of the Decision on Infringement

Direct Infringement

It was common ground that the word “for” (as used in the phrase “for treating neuropathic pain”) does not simply mean “suitable for”, but imports a mental element: it is the fact that the manufacturing is carried out with a new mental element (i.e. that it is now known that pregabalin is (or is plausibly predicted to be) effective for the treatment of neuropathic pain) that makes the claim novel. However, the question that fell to be decided was what was the nature of this mental element?

The Court of Appeal considered this question in some detail in a previous judgment in these proceedings, in the appeal from the decision not to grant an interim injunction. Floyd LJ held that the subject matter of the claim was concerned with the ultimate end use of the medicament, and it was the intention for which the compound is administered which is at the heart of the invention. Accordingly, infringement of a Swiss form claim did not require a subjective mental element on the part of the manufacturer (as had been previously held by Arnold J in the decision under appeal), but instead, a manufacturer would be liable for infringement when he “knows or foresees that users will intentionally administer it for pain”. Arnold J agreed with Actavis and the Secretary of State that the Court of Appeal’s commentary on this point was obiter (because the Court of Appeal did not overturn his original decision to refuse interim relief) and, therefore, was not binding. However, he nonetheless considered the judgment to be highly persuasive and, despite expressing “considerable doubts” as to whether it was correct, went on to apply it.

Arnold J dismissed Warner-Lambert’s submissions that Floyd LJ’s interpretation of the word “for” was no different from a pure test of foreseeability on the part of the manufacturer that its pregabalin would in fact be used for the treatment of pain. Instead he emphasised that the test requires two mental states: (1) a knowledge or foresight by the manufacture that (2) users will intentionally administer pregabalin for treating pain. As to whose “intention” is relevant, Arnold J held that the intention of the prescribing doctor is highly relevant, if not exclusively so, as it is the prescribing doctor who has the medical expertise and intends to produce the new therapeutic effect. However, it is not sufficient that the doctor intends pregabalin from any source to be administered for the treatment of pain, as submitted by Warner-Lambert, as infringement must depend on what the manufacturer can foresee happening with the pregabalin that it manufactures, not pregabalin made by others. Therefore, Arnold J held there would be no intentional administration of Lecaent for the treatment of pain if Lecaent is dispensed in circumstances where the doctor has prescribed generic pregabalin for pain and the pharmacist does not know the indication for which it has been prescribed.

After considerable hesitation, Arnold J also decided that the intention of the pharmacist is relevant where there pharmacist knows that the doctor has prescribed generic pregabalin for the patented indication (which occurs in 5% of cases), but nonetheless dispenses the skinny label generic product. Therefore, the key question the judge had to decide was whether it was foreseeable to Actavis that, in those 5% of cases where the prescription indicated that generic pregabalin had been prescribed for pain, the pharmacist would dispense Lecaent despite the fact it was not licenced for that indication.

As Swiss form claims are process claims directed at the manufacturer of the medicament, this mental element of the manufacturer must be assessed as at the date of manufacture, regardless of when the manufactured drug is subsequently sold. Therefore, to explore the potential consequences of Actavis’ differing states of knowledge as the case progressed to trial, Arnold J analysed the infringement position as at three different dates, namely as at 8 December 2014, 17 February 2015 and 15 July 2015, and on the assumption that Actavis had manufactured Lecaent in three separate batches similarly spaced out in time.

At all times, Actavis was held not to have infringed the patent. The case for infringement was strongest in relation to the earliest date, where Lecaent was manufactured between June and October 2014, but Arnold J concluded that it was not foreseeable to Actavis that Lecaent manufactured in this period would be intentionally administered for the treatment of pain save in a small number of exceptional cases which he regarded as de minimis. In coming to this decision, Arnold J took into account the fact that (i) Lecaent was marketed under a skinny label; (ii) Actavis had notified superintendent pharmacists that Lecaent was not licensed for the treatment of Neuropathic pain; (iii) it was reasonable for Actavis to assume that its message would be disseminated by the superintendent pharmacists to those under their supervision; and (iv) Actavis was aware that Warner Lambert was offering brand equalisation deals to its main customers (i.e. agreeing to discount the price of the branded product so as to compete with the price of the generic product and preserve its own market share).

Indirect Infringement

Despite the Court of Appeal allowing Warner Lambert’s appeal against Arnold J’s earlier decision to strike out the indirect infringement claim, Arnold J was puzzled by the Court of Appeal’s reasoning and took the opportunity to reiterate the view that he expressed in his earlier judgment that as the claim is to a process of manufacture and there is no act of manufacture by any party downstream from Actavis, nor any prospect of such an act, Actavis’ pregabalin product cannot be “suitable for putting, or intended to put, the invention into effect”: either the invention has already been put into effect by the time that Lecaent leaves Actavis’ hands or it is not put into effect at all.


Given that Swiss form claims have been around for a long time, it is surprising that there has been little judicial guidance in the UK (or elsewhere) on their scope of protection until now. Therefore, this decision has been welcomed by practitioners in this area. However, we doubt this is the end of the saga. An appeal is likely, possibly even to the Supreme Court ultimately.

In the meantime it does bring some comfort to generic manufacturers who plan to launch generic products under a skinny label, although in this case the fact that Actavis had taken some additional steps over and above applying for a skinny label to avoid infringement was an important factor. However, what additional steps are required to avoid infringement is likely to depend on the circumstances of the case. It might be enough for a generic manufacturer to write to pharmacists to inform them that its generic product is not licensed for the patented indication (as Actavis did), but depending on the market in question and on the steps the patentee has or has not already taken, this may not be enough. The timing of such additional steps is also likely to an important consideration. On the one hand such steps are likely to be more effective if taken in advance of the generic product coming onto the market. But on the other, a generic manufacturer wishing to gain a commercial advantage by surprising the patentee with the timing of its launch is likely to be reluctant to take any such steps prior to launch.

Arnold J’s judgment concludes with a very poignant afterword expressing the need to address the issues associated with the enforcement of second medical use patents, as highlighted by this case. In his view, the solution lies in separating the patented market for a substance from the non-patented market by ensuring that prescribers write prescriptions for the patented indication by reference to the patentee’s brand name and write prescriptions for non-patented indications by reference to the INN, and suggested that centralised and authoritative guidance should be provided to prescribers and other relevant stakeholders. How such a centralised system can be achieved in practice across what is a rather decentralised healthcare system in the UK is not clear. Nevertheless, Arnold J has called on the Secretary of State to try to ensure that such a system is implemented and it will be interesting to see whether this results in any changes which improve the environment for the enforcement of second medical use patents in the UK.

Finally, this judgment only deals with Swiss form claims and Arnold J makes it clear that it should not be assumed that anything in the judgment necessarily applies to claims drafted since the introduction of the EPC 2000 (i.e. claims in the form “substance X for use in treatment Y”). Therefore, where this judgment leaves EPC 2000 claims remains unclear. Such claims have no nexus to the manufacturer or the manufacturer’s “mental state”, even though the intention of the legislator in introducing the purpose limited product claims appears to have been to provide a claim format which afforded equivalent protection to the Swiss form claim.

Published with minor amendments in the IP Forum, Issue 103: December 2015