Pregabalin patent – Supreme Court finds the patent bargain broken

The United Kingdom Supreme Court today (14 November 2018) handed down a significant patent decision[i] relating to the degree to which a patentee must demonstrate an invention at the time of making the application.  At the heart of the decision lies what, in the Judge’s view, is the fundamental rationale of the patent system – that the inventor obtains a monopoly in return for disclosing the invention and dedicating it to the public for use after the monopoly has expired.


The case related to Warner-Lambert’s patent[ii] for pregabalin.  Pregabalin is marketed under the brand name “Lyrica”. Lyrica is one of four first-line treatments recommended by NICE for neuropathic pain. It is one of the most successful drugs in the United Kingdom.


As pregabalin was already known, the patent contained claims directed to the medical use of pregabalin, including the treatment of pain (claim 1).  Claim 3 was more specific, being directed to the treatment of neuropathic pain (pain resulting from damage or injury to the nerves).  The Court agreed with the referring instances in agreeing that “neuropathic pain” was to be interpreted broadly, as covering all such types of pain.


The central question was whether the patent application as filed disclosed some reason to regard the use of pregabalin for the treatment of neuropathic pain as “plausible”.  Only if this question were answered in the positive could the patent fulfil the requirements of sufficiency[iii].


The Supreme Court acknowledge the practical difficulty of demonstrating therapeutic efficacy at the stage when the patent application must in practice be made.  Nevertheless, the specification must disclose some reason for supposing that the implied assertion of efficacy in the claim is true; in other words, to make it “plausible”.  The test is relatively undemanding, but cannot be deprived of all meaning or reduced to little more than a test of good faith.


The experimental data in the specification were predictive of efficacy for the treatment of inflammatory pain, but there were no data to make it plausible that pregabalin was effective for the treatment of any kind of neuropathic pain. Claim 3 would stand only if it would have suggested to the skilled person that there was some unifying principle which made it plausible that pregabalin would also work with neuropathic pain.


To determine this question, the Supreme Court determined the correct question to be not whether the invention was plausible, but whether the specification discloses something that would make it so in the eyes of the skilled person.  In the present case there was nothing to suggest, even as a hypothesis, that pregabalin works with peripheral neuropathic pain by blocking central sensitisation.


Although the patent was found insufficient, the Supreme Court unanimously held that if Claims 1 and 3 had been valid, they would not have been infringed.  The infringement issues will be the subject of a further bulletin in the near future.


CASEY’s comment


The decision strikes a balance between the interests of the patentee, who is required in practice to file at an early stage, often before the invention is understood, and third parties, who are entitled to be protected from wholly speculative “armchair” (in the words of the Court) patents.


Although the plausibility hurdle is low, patent applicants need to be mindful of it.  If data supporting a particularly important aspect is not available, a plausible hypothetical reason why this aspect works should always be included in the description.




[i] Warner-Lambert Company LLC (Respondent) v Generics (UK) Ltd t/a Mylan and another (Appellants) [2018] UKSC 56

[ii] EP(UK)0641330

[iii] UK Patents Act Section 14; European Patent Convention Article 83

Posted on: 14th November 2018