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Infringement of second medical use claims in the UK: the Patents Court takes with one hand but gives with the other

02 March 2015

Background

The case concerned the drug pregabalin, which is marketed by Warner-Lambert (part of the Pfizer group) under the trade mark Lyrica® for three indications: epilepsy, generalised anxiety disorder (GAD) and neuropathic pain.  Patent protection for the active compound per se expired in May 2013 but Warner-Lambert also holds a second medical use patent (EP 0 934 061 B) with Swiss form claims directed to the use of pregabalin and pharmaceutically acceptable salts thereof in the manufacture of a pharmaceutical composition for treating pain (but without any equivalent claims covering the treatment of epilepsy or GAD).

The lead defendant, generic drug manufacturer Actavis, applied for and is on the verge of obtaining marketing approval for generic pregabalin for treating epilepsy and GAD, i.e. the indications not covered by the claims of Warner-Lambert's second medical use patent.  Upon issuance of the marketing approval, Actavis intends to launch the generic product (under the trade mark Lecaent®) with a so-called "skinny label" referring only to non-infringing indications, epilepsy and GAD.

However, in such situations uncertainty arises because prescriptions typically refer only to the product being prescribed by the doctor, not to the indication for which it is being prescribed.  In the UK, unless a doctor specifies a particular brand (and, to save costs, they are encouraged not to specify a brand), the pharmacist is entitled to dispense any branded or unbranded version of the product.  In this case, Warner-Lambert feared that doctors would prescribe "pregabalin" for the treatment of pain (i.e. without specifying a brand), and the pharmacist would dispense Actavis's Lecaent® product, without realising that the use of pregabalin to treat pain was still the subject of Warner-Lambert's patent protection.

Warner-Lambert sought an unprecedented interim injunction to compel Actavis inter alia to make it a condition of any agreement with pharmacies for the supply of Lecaent® that the pharmacy "use reasonable endeavours not to supply or dispense Lecaent® to patients who have been prescribed pregabalin for the treatment of pain" and to notify the superintendent pharmacists in each such pharmacy that dispensing Lecaent® for the treatment of pain infringes the patent rights held by Warner-Lambert.

The decision

In reaching his decision on whether to grant Warner-Lambert's request for an interim injunction, Arnold, J. applied the well-established legal principles set out in American Cyanamid Co vs Ethicon Ltd [1975] AC 396; in particular, whether there was a serious issue to be tried and the need to balance the risk of injustice to the parties if the relief were to be granted.

On the issue of whether there was a serious issue to be tried, Arnold, J. confirmed that Swiss form claims cover a process for the production of medicaments that are suitable and intended for treating the defined indication.  He noted that Swiss form claims are directed at the manufacturer of the medicament, but "do not touch" the doctor or pharmacy (except in the case of extemporaneous preparation by the pharmacist).  Thus, it followed that the relevant intention to be considered is that of the manufacturer (in this case, Actavis), not that of the doctor or pharmacist.  Since Warner-Lambert did not rely in its pleadings upon any allegation of intention on the part of Actavis for Lecaent® to be used for the treatment of pain, Arnold, J. concluded that there was no serious issue to be tried.  The fact that it was foreseeable that doctors would be likely to prescribe, and pharmacists likely to dispense, Actavis's Lecaent® product for the treatment of pain was deemed not sufficient for the Court to consider a finding of infringement by Actavis.

On the issue of balance of risk of injustice to the parties, Arnold, J. held that there was a greater risk of substantial unquantifiable loss to Actavis if the interim injunction were wrongly granted than there was of substantial unquantifiable loss to Warner-Lambert if the injunction were wrongly refused.

On this basis, Arnold, J. refused Warner-Lambert's request for the interim injunction.

Subsequently, in a decision of 6 February 2015, Arnold, J. refused a request by Actavis to strike out or summarily dismiss Warner-Lambert's infringement claim and, at the same time, granted permission for Warner-Lambert to amend its particulars of infringement to plead a case that Actavis intended Lecaent® to be used for the treatment of pain

A full trial is scheduled for June 2015 (the decision of which we will report in due course).

A twist in the tail

In an interesting further development in the case, on 26 February 2015 the High Court granted to Pfizer (parent company of Warner-Lambert) an order compelling the UK healthcare authority National Health Service England (NHSE) to issue central guidance that prescribers must prescribe Warner-Lambert's branded Lyrica® product when using pregabalin for pain and for those prescriptions pharmacists must dispense Lyrica®.

This innovative strategy by Pfizer's legal team was presumably prompted by Arnold, J.'s encouragement to the UK healthcare authorities (in his original decision of 21 January 2015) to issue guidance to doctors and pharmacists on the prescription of generic products which remain the subject of second medical use patents.  The patentee's request was based on NHSE being an intermediary or conduit and relied upon jurisprudence developed in the areas of trade marks and internet service providers (ISPs).

Impact of these decisions

The original decision of 21 January 2015 represents the first detailed guidance from the UK courts on the protection afforded by Swiss form medical use claims.  Arnold, J. held that Swiss form claims are infringed only when there is subjective intent by the manufacturer for the product to be used for the patented second medical use (it being irrelevant, at least in relation to Swiss form claims, whether the prescribing doctor or dispensing pharmacist intend such use).

If, as anticipated, the decision at full trial finds non-infringement by Actavis of Warner-Lambert's second medical use patent, then it raises serious questions about the enforceability of Swiss form claims against 'skinny label' generic products (even, as in this case, where there is a reasonable likelihood that a significant proportion of the prescribed generic product will be used for treatment of the patented indication).  Of course, any such decision is likely to be appealed to the Court of Appeal and, thereafter, possibly up to the Supreme Court.

However, the order granted to Pfizer compelling NHSE to issue central guidance to doctors and pharmacies to respect second medical use patent rights would appear to provide a very neat solution (in the UK, at least) to the problem faced by patentees seeking to protect such inventions from skinny label generic competition.  It remains to be seen, though, how effective such an order is in practice, given that prescriptions typically do not specify the use for which a medicament is prescribed.  Consequently, if a doctor fails to identify the branded Lyrica® product, or the indication, when prescribing pregabalin for pain, the downstream pharmacist may be oblivious to the intended use of the medicament.

It is worth noting that in Europe, at least, second medical use inventions must now be protected using the purpose-limited product claim format established by the EPC2000 patent reforms ("Product X for use in treating Indication Y").  The Boards of Appeal of the EPO have already held that such claims have a different scope from that of Swiss form claims (see Decision T 1780/12), a fact implicitly acknowledged by Arnold, J. in his decision, and so may provide stronger patent protection for second medical use inventions.

In summary, this decision highlights the need for careful thought and experience in formulating the best suite of claims and devising an effective strategy to protect second medical use inventions.

 

Please contact Stephen Smith for further information.

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