In a judgement1 which provides a comprehensive analysis of the issues that should be taken into consideration when determining infringement of second medical use claims in the UK, Mr Justice Arnold refused to grant injunctive relief to the patentee, Warner Lambert.  He held that there is no serious issue to be tried with regard to the patentee’s claim that the generics manufacturer, Actavis, will infringe its second medical use patent.  Furthermore, he held that, even if there was a serious issue to be tried, the balance of the risk of injustice would favour refusal of the requested relief.

Facts of the case

Warner-Lambert Company LLC (Warner Lambert) markets the prescription-only drug pregabalin for three different indications under a single registered trade mark, LyricaTM.  The drug itself is no longer patent-protected, but Warner Lambert still has a second medical use patent for one of the indications, the treatment of neuropathic pain.

The key claims were in the so-called “Swiss form” medical use format and read as follows:

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.

A generics supplier (Actavis) is on the verge of obtaining a so-called “skinny label” marketing authorisation for generic pregabalin limited to the treatment of the other two known indications, epilepsy and generalised anxiety disorder. They plan to launch the product under the trade mark LecaentTM.  A number of other generic suppliers are also making preparations to launch generic pregabalin.

Both Warner Lambert and Actavis are taking a number of steps to try and prevent the dispensing of LecaentTM for pain.  Nevertheless, Warner Lambert is concerned that despite the marketing authorisation being limited to epilepsy and generalised anxiety disorder, LecaentTM will in fact be used to treat pain.

A full trial pertaining to the validity and infringement of Warner Lambert’s patent is scheduled for June 2015, but meanwhile Warner Lambert sought interim relief. In essence, Warner Lambert wanted to impose upon Actavis the duty to carry out several particular steps to ensure that LecaentTM would not be dispensed for use in the patented indication2.  Actavis countered that the infringement claim has no real prospect of success and in the alternative that the balance of the risk of injustice favours refusal of the relief sought by Warner Lambert.

Enforcement and infringement analysis of second medical use claims

Second medical use claims are limited to one or more specific indications of a drug, so third parties are lawfully entitled to enter the market for any non-patented indications of the drug. However, in practice, use of the generic drug for the patented indication may occur, particularly if, as in the instant case, the dosage for the patented indication and the non-patented indication is the same.

The risk of such “off-label” use of a generic drug is potentially increased by several features of the UK’s healthcare system.  For example, doctors are encouraged to prescribe “generically”, which leaves pharmacists free to dispense either branded or generic versions of the drug (whereas a specific brand must be dispensed if it is explicitly identified on the prescription). Pricing structures provide a commercial incentive for pharmacists to dispense a generic version of any drug where possible. Moreover, about 95% of prescriptions do not state the indication for which the drug has been prescribed.

Mr Justice Arnold deemed that it must be determined whether, in such circumstances, the generic supplier will infringe the second medical use patent unless he takes positive steps to prevent his generic version of the drug being dispensed for patients who have been prescribed the drug for the patented indication.

Starting with the previously established premise that a medical use claim in the Swiss form is a process claim, Mr Justice Arnold went on to hold that the word “for” in Swiss form claims imports a requirement of subjective intention on the part of the manufacturer that the medicament will be used for treating the specified indication.  Thus, whether a manufacturer of a drug infringes a Swiss form claim depends on whether he intends for the drug to be used for the patented indication.

Given that Warner Lambert did not rely upon any allegation of subjective intention on the part of Actavis, Mr Justice Arnold concluded that Warner Lambert’s claim of primary infringement3 does not raise a serious question to be tried.

In passing, he also indicated that no wholesaler or pharmacist would use LecaentTMto prepare a pharmaceutical composition (Actavis being the one preparing a pharmaceutical composition), so there is no contributory infringement4

For completeness, Mr Justice Arnold also considered the balance of the risk of injustice.  He concluded that granting he relief sought by Warner Lambert would create a greater risk of injustice than refusing it.

Impact of the decision

Whilst this case only concerned an application for interim relief, it is significant because it represents the first decision handed down by a UK judge regarding the construction of second medical use claims and its impact on the assessment of infringement.  It is particularly interesting that Mr Justice Arnold held that it is the subjective intention of the manufacturer of the drug that matters when assessing infringement of a Swiss form medical use claim. 

It is important to appreciate, however, that many medical use claims are in the EPC2000 form (“Active agent X for use in the treatment of indication Y”), rather than the Swiss form (“Use of active agent X in the manufacture of a medicament for treating indication Y”).  Mr Justice Arnold highlighted that according to decision T1780/12 of the EPO’s Appeal Board, claims in EPC 2000 form have a different scope of protection to claims in Swiss form.  

He explicitly emphasised that it “should not be assumed that anything I say in this judgment about Swiss form claims necessarily applies to EPC2000 claims”.  This is a real pity, given that medical use claims in the Swiss form are being phased out: Whilst they are permissible in applications and patents filed before 29 January 2011, medical use claims in applications filed on or after that date must be in the EPC2000 form.  Guidance on the appropriate construction and assessment of infringement of EPC2000 form medical use claims is therefore still elusive for now.