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Neurim and Flynn v Mylan [2022] EWCA Civ 699

The Court of Appeal dismissed Mylan’s appeal against the finding of the Patents Court that European Patent (UK) No. 3 103 443 (“EP443”), a second medical use patent for a prolonged release formulation of melatonin owned by Neurim (and under which Flynn holds an exclusive licence) was valid and infringed by Mylan.

The Patents Court Decision
In a judgment handed down on 10 February 2022, affirmed following an oral hearing on 4 March 2022, Mr Justice Marcus Smith dismissed Mylan’s challenge to the validity of EP443, and granted an injunction restraining Mylan from infringing EP443 with effect from 10 March 2022. The judge’s reasoning was the same as set out in his judgment dated 4 December 2020, in which he dismissed Mylan’s challenge to the validity of European Patent (UK) No. 1 441 702 (“EP702”), of which EP443 is a divisional. Mr Justice Marcus Smith maintained his reasoning for EP702 in relation to EP443, notwithstanding that EP702 was revoked at the EPO mere weeks after he found it to be valid (resulting in there therefore having been no appeal in the EP702 UK case).

The Appeal
On 8 March 2022, Mylan made an urgent application to the Court of Appeal for permission to appeal Mr Justice Marcus Smith’s judgment on the validity of EP443. The Court of Appeal granted Mylan permission to appeal, directed that the appeal be heard on an expedited basis (as EP443 is due to expire on 12 August 2022), and stayed the injunction granted by Mr Justice Marcus Smith pending the outcome of the appeal.
The appeal was heard on 19 May 2022 before Lord Justices Arnold, Birss and Newey, with Lord Justice Arnold giving the lead judgment on whether Mr Justice Marcus Smith had made an error of principle in his assessment of the validity of EP443. The only such error identified by Mylan was the rejection of its so-called ‘lay-patient argument’.

The ‘Lay Patient Argument’
Mylan’s ‘lay-patient argument’ was, at its core, that EP443 failed to plausibly disclose the effect it claimed.

EP443 claimed that the use of a prolonged release formulation of melatonin would improve quality of sleep for patients aged 55 and older suffering from a form of insomnia characterised by non-restorative sleep (“NRS”). It was common ground that the plausibility of the claimed effect depended on what was disclosed by a number of examples in EP443, namely Example 2 (describing the results of study on the effects of a prolonged release formulation of melatonin on subjectively assessed sleep quality in 170 elderly insomnia patients) and Example 3 (describing the results of a similar study carried out with 131 primary insomnia patients aged 20-80). It was also common ground between the parties that the key data disclosed by Examples 2 and 3 was the responses given by participants to a question asking them to compare the quality of their sleep using the medication with non-medicated sleep on a scale ranging from “more restless than usual” to “more restful than usual”.

Mylan argued that the responses to this question could not plausibly disclose the claimed effect of melatonin on NRS, as they failed to distinguish between NRS and other forms of insomnia when viewed from the perspective of what the patients (as laypeople) would have understood the question to mean. Mylan also argued that there was a contradiction within the specification of EP443 and, in particular, that one sentence of the specification could be interpreted as assuming that the patients’ responses about their quality of sleep referred to forms of insomnia other than NRS.

This argument was rejected by Mr Justice Marcus Smith in his judgment on the validity of EP443 (as well as in his earlier judgment on the validity of EP702), who held that the claimed effects were plausibly disclosed.

The Court of Appeal’s Decision on the Lay Patient Argument
The Court of Appeal upheld Mr Justice Marcus Smith’s reasoning in rejecting the lay-patient argument, finding that:

• The judge had correctly focused his reasoning upon the purpose of the question described in Examples 2 and 3. The skilled person, having regard to the specification of EP443 as a whole, would understand that purpose to be to demonstrate that melatonin is effective in treating NRS.
• The judge was also correct to say that the skilled person, upon reading Examples 2 and 3, would assume the studies described were conducted in a competent manner and the questions were “administered in a way which was capable of producing meaningful data”. Whilst this was “not to reduce plausibility to a mere test of good faith, because plausibility depends on the reported results of the trials”, it was found that, even if the “quality of sleep” question was not specific to NRS, there were two ways in which it could have been administered so as to product meaningful data (namely whether it was asked in a chronological sequence with the other questions or asked in isolation). All that was then required was “a possible way in which the Examples could have been competently performed in the absence of anything to indicate that they were not competently performed”.
• Even if the question regarding “quality of sleep” had been asked in isolation and without further instructions, based on the expert evidence it was not necessarily correct to say that it could not have related to NRS specifically.
• The judge was entitled to reject the evidence of Mylan’s expert on the lay-patient argument for the reasons he gave, and to prefer that of the claimants’ expert.
• Although Mylan was correct that there was an apparent contradiction within the specification of EP443, it had failed to adduce expert evidence on how the skilled reader would view and resolve that apparent contradiction. As a result, the court could not draw a conclusion on that particular argument, and found that Mylan was not entitled to rely upon it.

The Court of Appeal therefore dismissed Mylan’s appeal.

The full judgment can be accessed here.

Amy Crouch and Eliza Jones, Simmons & Simmons LLP