In a complex and lengthy judgment, a majority of the Supreme Court rejected Warner-Lambert's appeal against a finding that the Swiss-form claims 1 and 3 of its second-medical use patent was invalid. The Patent lacked plausibility and was therefore insufficient.

The test for plausibility, as an element of a sufficiency analysis, as well as the role of post-published data have also been clarified. The test for plausibility was relatively undemanding but a bare assertion of therapeutic efficacy was not enough – it required disclosure of reasonable scientific grounds that the invention would work. This threshold is higher than that set by the Court of Appeal.

The majority also upheld Actavis' and Mylan's cross-appeal that the specification did not make peripheral neuropathic pain plausible either. There had been no error in the finding that an application by Warner-Lambert to amend the patent after judgment was an abuse of process.

Although infringement was no longer an issue, in light of the importance of the point, it was considered in detail in the judgment. That there could be indirect infringement of a Swiss-form Patent was unanimously rejected. In relation to direct infringement, the majority opinion was that even if claims 1 and 3 had been valid, they would not have been infringed. All of the Supreme Court judges rejected the Court of Appeal's "foreseeability" test. Lord Sumption and Lord Reed preferred an "outward presentation test", with the test for infringement being whether the product as it emerged from the manufacturing process, including any labelling or accompanying leaflet, was presented as suitable for the patented use. Lord Hodge and Lord Briggs preferred Arnold J's test that the alleged infringer must subjectively intend to target the patent-protected market. Lord Mance agreed that the test depended on the objective appearance and characteristics of the product as it was prepared, presented and put on the market but left open the possibility (i) that in rare cases, context might make it obvious that these were not to be taken at face value, and (ii) there might be circumstances in which a generic manufacturer should positively exclude the patented use.

As was recognised in all of the judgments, none of the proposals provided a perfect solution that balanced the competing public policy points. All, however, felt that the Court of Appeal's "foreseeability" test weighted the balance too heavily in favour of the patentee, would effectively destroy a generic market for non-patented indications and exposed downstream parties to significant legal risk. In terms of practicalities, the "outward presentation test" preferred by the majority (subject to some caveats) is the most straightforward to implement of all of the tests proposed. Although the door has been left open to address any attempt to game the system. This should provide more legal certainty to both innovators and generic pharmaceutical companies.

The full judgment can be found here.

You can read a full analysis of the case by Rachel Fetches, Partner and Maherunesa Khandaker, IP Solicitor here.

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