The Warner Lambert v Actavis cases on pregabalin-based medicines have been before the UK Courts on no less than seven occasions since the beginning of 2015 and have had to deal with the thorny issue of the construction, infringement and the relief available under second medical use patents. Readers will recall our article in the May issue of On The Pulse, which summarized the High Court’s refusal to grant Warner Lambert’s request for preliminary injunctive relief to restrain Actavis’ alleged cross-label use of its Lecaent (pregabalin) medicament for the patented indication of pain. At that stage, Arnold J held that there was no serious issue to be tried and that, even if there was an arguable case of infringement, the balance of the risk of injustice favoured the refusal of the relief sought.

The next installment came in the form of the Court of Appeal decision (Floyd LJ giving the leading judgment), which was handed down on 28 May 2015. The Appeal Court upheld Arnold J’s decision not to order the preliminary injuction sought on the basis that Arnold J had properly evaluated the evidence before him and reached a sensible conclusion on the balance of justice. However, perhaps more significantly, the Court of Appeal adopted a different approach to the construction of Swiss-form second medical use claims that could have a significant impact on the assessment of infringement of such claims. In particular, the Court of Appeal held that the key issue is what the manufacturer knows (including constructive knowledge) or could reasonably foresee about the ultimate intentional end use of the product for the patented indication. In the Court of Appeal’s opinion, infringement would occur if the manufacturer knew or could reasonably foresee the ultimate intentional use for pain (the patented indication). The manufacturer did not necessarily need to have that specific intention or desire itself.

The main action came before Arnold J at the end of last term and a decision was handed down on 10 September 2015. Despite finding that the main claims of the patent were invalid due to insufficiency, Arnold J went on to consider the infringement position. Although appearing to disagree with the Court of Appeal’s test of reasonable foreseeability, Arnold J applied it and held that, on a number of dates in question, it was not reasonably foreseeable that Actavis’ Lecaent medicine would have been intentionally administered for the treatment of pain and was therefore non-infringing. This was principally on the basis that the doctor would not know which company’s pregabalin medicine would be dispensed, and the pharmacist was unlikely to know the indication for which it was prescribed (and if it did, would dispense Warner Lambert’s branded pregabalin medicine (Lyrica) for the treatment of pain as a result of the letters written to superintendant pharmacists by Actavis).

Arnold J also refused to find indirect infringement, noting that he was “puzzled”, “baffled” and did not understand the reasoning behind the Court of Appeal’s decision to reverse his earlier strike out decision. Returning to the theme of his decision on preliminary injunctive relief, the Judge also stressed that the answer to this problem should not be found in the patent system, but should lie in centralized and authoritative guidance instructing prescribers to prescribe by brand name where patents exist. Originators and generics should therefore follow Arnold J’s guidance and engage at an early stage with stakeholders such as NHS England.