Neurim Pharmaceuticals (1991) Limited & Anor. v Teva UK Limited

On a renewed application for an interim injunction, the court must assess the evidence at the date of the hearing and may take account of a material change in circumstances. The American Cyanamid guidelines are flexible aids to analysis, rather than a rigid sequential checklist. The central inquiry is which course is likely to cause the least irremediable prejudice. The parties’ positions must be assessed separately. Uncertainty in quantifying a party’s losses, including the loss of a first-mover advantage, may make damages inadequate. A patent proprietor’s loss of the ability to exclude a competitor is assessed through those principles; it is not treated as a separate non-monetary factor divorced from the damages inquiry. The application was refused because damages were adequate for the claimants, while they were inadequate for the defendant, and the balance of risk favoured the defendant.

The claimants sought a second interim injunction restraining Teva from selling melatonin products pending trial or, in reality, until expiry of the patent on 12 August 2022. A first application had been refused in [2022] EWHC 954 (Pat). In the meantime, the Court of Appeal had rejected Mylan’s appeal concerning the same patent in [2022] EWCA Civ 699, and Mylan had been injuncted.

The court considered whether there had been a significant and material change, the strength of the merits, the adequacy of damages, the relevant status quo, the parties’ opportunities to clear the way, and the wider implications for the patent system. The central issue was whether interim relief would reduce the risk of irremediable injustice pending trial.

1. Application refused. The claimants failed to establish a sufficient basis for restraining Teva until patent expiry. Permission to appeal was also refused, subject to the Court of Appeal giving permission if it considered the earlier Mylan judgment decisive.
2. A renewed application for interlocutory relief should ordinarily be supported by a significant and material change in circumstances. Here, the court accepted that the evidence and circumstances had changed sufficiently to justify considering the application afresh.
3. The American Cyanamid principles are guidelines assisting the exercise of discretion. They are not a rigidly sequential checklist. The court should take the course likely to cause the least irremediable prejudice, while considering the parties’ positions separately.
4. The court could not form a clear view on the merits. The Court of Appeal’s decision in the Mylan litigation did not resolve Teva’s different validity and infringement case, which involved different evidence, prior art and arguments.
5. Damages were an adequate remedy for the claimants. Their pre-expiry loss could be calculated with reasonably high accuracy. Their post-expiry loss was unlikely to be significant, and remaining uncertainty could be addressed through the ordinary assessment of damages.
6. Damages were inadequate for Teva. Before expiry, Teva’s fluctuating sales volumes, prices and market share made its counterfactual losses substantially uncertain. The same uncertainty extended after expiry because an injunction would deprive Teva of its first-mover advantage and established customer relationships.
7. The relevant status quo was the position when the second application was deemed served on 8 June 2022. By then Teva had been on the market for nearly eight months and expiry was close. That factor, together with the balance of irremediable harm, favoured refusing relief. The claimants’ loss of the ability to exclude Teva had to be assessed under the American Cyanamid guidelines and did not create an independent answer.
8. The claimants were ordered to pay Teva’s costs in any event, assessed on the indemnity basis if not agreed, and to make an interim payment of £100,000 within 14 days.

The judgment describes an earlier interim application against Teva, refused in [2022] EWHC 954 (Pat). It also records the separate Mylan litigation:

• Court of Appeal — Mylan’s appeal was rejected in [2022] EWCA Civ 699.
• High Court (Patents Court) — the present court refused the second interim application against Teva.