English High Court denies Mylan a stay in Neurim litigation

Mylan has failed to secure a stay in litigation centring on a melatonin-based insomnia patent at the English High Court.

The Patents Court, High Court of Justice, delivered the blow to the pharmaceutical company (which is now part of Viatris) on Friday, October 29.

Mylan launched a 2mg prolonged-release melatonin product to improve the restorative quality of sleep for patients suffering from primary insomnia in September 2020.

Neuroscience drug company Neurim Pharmaceuticals claimed that Mylan’s product infringed EP (UK) number 3,103,443.

The ‘443 patent was granted on June 2021 but will expire in August 2022: a shorter than usual life because it is a divisional of an earlier patent covering the same thing—that being a method for treating primary insomnia by way of a medication comprising melatonin.

In 2020, Neurim sued Mylan for patent infringement, relying on the parent patent to the ‘443 patent. In response, Mylan said that the parent patent—EP 1,441,702—was invalid.

In December 2020, the English High Court found the ‘702 patent to be valid and that it had been infringed by Mylan.

However, during the same month, the European Patent Office’s (EPO) Technical Board of Appeal (TBA) found the ‘702 patent to be invalid due to insufficiency, and the patent was revoked. The English High Court accordingly revoked its decision.

Mylan then sought to bring Neurim’s patent application in respect of the ‘443 patent to the EPO’s attention, specifically in relation to the insufficiency of its parent patent.

However, the EPO considered Mylan’s observations and proceeded to grant the ‘443 patent anyway the following year. Mylan referred its concerns regarding the ‘443 patent to the TBO, and Neurim’s initial infringement claim continued at the English High Court.

To allow Neurim the opportunity to secure some form of injunctive relief before the ‘443 patent expires in August 2022, the court decided that Neurim should be permitted to litigate the preliminary issues on an expedited basis.

Meanwhile, the parties became aware that another generic manufacturer, Teva, was looking to bring its own generic melatonin insomnia treatment to the UK market.

Mylan applied to stay the English proceedings while the decision of the TBA in relation to the ‘443 patent is outstanding. The generics manufacturer argued that the ‘443 patent is unlikely to be valid as the parent patent was insufficient.

However, even an expedited process at the TBO would mean that the appeal related to the ‘443 patent is not heard until late 2023 or early 2024.

Mylan said that, if the proceedings in the UK continue and Neurim secures an injunction against Mylan but, later down the line, the EPO revokes the ‘443 patent, Teva will have picked up the market share that Mylan would have enjoyed.

In response, Neurim confirmed that it is committed to bringing proceedings against Teva and restoring its monopoly in relation to the product covered by the ‘443 patent.

On Friday, Deputy High Court Judge Ian Karet said he must consider the extent to which a refusal of a stay will irrevocably deprive a party of any benefit which the concurrent jurisdiction of the EPO and the High Court is intended to confer.

Neurim had promised to repay to Mylan any damages or profits ordered to be paid in respect of infringement of the ‘443 patent if it is later revoked, either in the EPO or on an application by Teva in the UK. This countered Mylan’s argument that refusing the stay could potentially cause irrecoverable losses, considering Teva’s plans.

There were further reasons for refusing a stay, including the crucial timing of allowing Neurim to seek to obtain a final injunction before the expiry of the ‘443 patent.

“This point on timing thus favours Neurim,” Karet said. Granting a stay would open up the possibility of generic competition at the very end of the ‘443 patent's life, which could have a significant impact on Neurim.

“A decision on the preliminary issues will give the parties some more commercial certainty within a relatively short time and during the life of the patent,” Karet concluded.

The decision means that the preliminary issues will be heard at trial in December 2021. These are to include Neurim’s claims that the parties have already litigated all issues of infringement and validity, and so Mylan is estopped from asserting otherwise.

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