Second medical use claims – Court of Appeal rules on infringement

Warner-Lambert Company LLC v Generics (UK) Ltd (t/a Mylan) & Others 13 October 2016

Introduction

This is our latest report of many on this lengthy and hard-fought dispute. To recap on the proceedings to date, the dispute concerns the alleged infringement by Actavis of Warner-Lambert’s second medical use patent. 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. Following the main trial on the issues of infringement and validity, Arnold J held that Warner-Lambert’s patent was partially valid and that, in any event, Actavis would not have infringed the patent. Warner-Lambert appealed to the Court of Appeal on the issue of infringement and Actavis appealed Arnold J’s findings on validity. The most interesting aspect of the latest judgment concerns the infringement issues, which are discussed below at the expense of the validity issues (although it is worth noting that Arnold J’s findings on validity were upheld by the Court of Appeal).

Background

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.

Direct infringement

Throughout these proceedings, there has been a great deal of uncertainty about the correct approach to the assessment of direct infringement of Swiss-form claims. In an earlier decision not to grant Warner-Lambert an interim injunction, Arnold J decided that direct infringement of a Swiss-form claim required a subjective intention on the part of the manufacturer that a medicament would be used for treating a patented indication. In a subsequent Court of Appeal judgment, Floyd LJ took a different approach. In his view, the relevant intention was an objective one and a manufacturer would be liable for infringement if it “knows or foresees that users will intentionally administer [the medicament] for pain”. In the main trial which followed that Court of Appeal judgment, Arnold J expressed his disagreement with the Court of Appeal’s test and noted that the relevant part of the decision was technically obiter. In spite of this,he endeavoured to apply it. According to Arnold J’s interpretation of that infringement test, two separate mental states are relevant: (1) a knowledge or foresight by the manufacture that (2) users will intentionally administer pregabalin for treating pain.

Indirect infringement

In the main trial on infringement and validity, Arnold J expressed the view that, since a Swiss-form claim is a claim to a process of manufacture, and there is no act of manufacture by any party downstream of a manufacturer, there can be no indirect infringement of a Swiss-form claim. This view did not accord with earlier, albeit obiter comments made by the Court of Appeal, that there could be indirect infringement of a Swiss-form claim by persons, other than a manufacturer, who supplies the product to end users.

The Court of Appeal’s latest decision on infringement

Although it was not necessary for the Court of Appeal to make a finding on infringement, since the specific claims alleged to be infringed were held invalid, it nonetheless took the opportunity to provide guidance on the issue.

Floyd LJ reiterated that a test of purely subjective intention is not correct and that the mental element must be judged objectively, by reference to what a person knows or can reasonably foresee as the consequences of his or her actions. He went on to say that such an intention may be “negatived where the manufacturer has taken all reasonable steps within his power to prevent the consequences occurring”. He also made it very clear that Arnold J’s previous application of the test enunciated by the Court of Appeal was flawed, in that only the intention of the manufacturer, and not that of doctors and pharmacists, is relevant.

On the subject of indirect infringement, Floyd LJ disagreed with Arnold J’s view thaw that an absence of ‘downstream manufacture’ means there can be no indirect infringement of a Swiss-form claim. The relevant invention concerns the preparation of a composition. That preparation includes any packaging step performed by a manufacturer and any labelling step performed by a pharmacist.

Comment

While the Court of Appeal’s decision sets out persuasive guidance on the relevant legal tests to be applied, there are a number of uncertainties about the outcome derived from applying these tests in different factual circumstances. As far as direct infringement is concerned, it is still not clear what specific steps a manufacturer must take in order to negative an objective intention to infringe a Swiss-form claim. For example, in Actavis’ case, would writing to superintendent pharmacists alone have been enough? And how does the presence of prescribing guidance designed to avoid infringement affect the objective intention of the manufacturer? With regard to indirect infringement, while it seems that, in the light of this decision, a pharmacist who labels a package with a patented indication could commit indirect infringement, uncertainty clouds other factual scenarios such as those where pharmacists dispense a product in the knowledge that it will be used by a patient to treat a patented indication.

The position is rendered even more uncertain because at least Warner-Lambert has requested a review of the Court of Appeal’s decision by the Supreme Court. It is likely to be a number of months before it is known whether or not the Supreme Court will hear the case.