UK Court of Appeal overturns refusal of interim injunction against generic companies

In a significant ruling for the pharmaceutical industry, in April 2025, the Court of Appeal overturned a High Court decision and granted AstraZeneca an interim injunction preventing Glenmark Pharmaceuticals from launching its generic version of the blockbuster drug dapagliflozin. 

While the High Court subsequently found AstraZeneca’s patent invalid in the main action, the courts’ divergent decisions concerning its application for an interim injunction will be of interest in future cases of this nature. 

Background

Dapagliflozin, marketed by AstraZeneca under the brand name “Forxiga”, is a prescription-only SGLT2 inhibitor used in the treatment of type 2 diabetes, heart failure, and chronic kidney disease. AstraZeneca's patent for dapagliflozin expired on 15 May 2023, but it held two Supplementary Protection Certificates (SPCs) extending its market exclusivity until May 2028.

Multiple generic manufacturers challenged the SPCs' validity in late 2023. This culminated in a trial on validity and infringement that ran from 10-20 March 2025, with the judge reserving judgment.

On 20 February 2025, Glenmark notified AstraZeneca of its intention to launch a dapagliflozin product "at risk" i.e., before the court had ruled on the SPCs’ validity. On 6 March 2025, AstraZeneca applied for an interim injunction.

High Court’s decision

The application was heard by Michael Tappin KC, sitting as a Deputy High Court Judge (who had been the trial judge). In a judgment dated 28 March 2025 he refused the interim injunction applying the guidelines in American Cyanamid v Ethicon [1975] AC 396. He focused primarily on the adequacy of damages concluding that AstraZeneca’s potential losses from Glenmark’s generic launch could be quantified and compensated. By contrast Glenmark’s losses, including the loss of its “first-mover advantage” (of being the first company to launch a generic product), would be harder to assess if wrongly injuncted.

The judge was not persuaded by AstraZeneca’s evidence that price erosion or market disruption would occur before the Form of Order (FOO) hearing following his judgment in the main action. He concluded that the balance of convenience favoured Glenmark, and appeared to give little weight to AstraZeneca’s argument that Glenmark had failed to “clear the path” before launching.

Ultimately, he applied the American Cyanamid test sequentially and found the criteria for granting an injunction were not met.

AstraZeneca appealed this decision. 

Court of Appeal's decision

On 31 March 2025, Lord Justice Arnold granted AstraZeneca permission for an expedited appeal. On 16 April 2025, the Court of Appeal (Lord Justices Coulson, Arnold, and Warby) unanimously allowed AstraZeneca's appeal and granted the interim injunction until the conclusion of the FOO hearing. 

Arnold LJ delivered the leading judgment, focusing on three principal aspects: the new evidence since the High Court hearing, the adequacy of damages, and the significance of preserving the status quo in pharmaceutical patent litigation.

New evidence 

Arnold LJ emphasised that since the High Court hearing, new evidence had emerged showing that Glenmark would not be the only generic entrant. Two other generic companies were shown to be ready to enter the UK market imminently. This transformed what had been viewed by the first instance judge as a "real risk" into a "certainty" of multiple generic launches prior to the FOO hearing.

While this evidence alone was not sufficient to overturn the decision, it "put a different complexion on matters”. In particular, it significantly increased the likelihood of a downward price spiral resulting from market competition, leading to commercial consequences that could not be easily reversed, even if AstraZeneca ultimately succeeded.

Application of the American Cyanamid test

Arnold LJ applied the American Cyanamid test as follows:

1. Serious question to be tried: It was undisputed that AstraZeneca’s claim raised a serious issue (the validity and infringement of the SPCs).
2. Adequacy of damages for the claimant (AstraZeneca): The High Court had found that damages would be adequate, but the Court of Appeal disagreed. Given the certainty of a price spiral and the potential for irreversible harm to its market position and pricing, Arnold LJ concluded that there was real doubt about the adequacy of damages. In reaching this conclusion, he found that not enough weight had been given to the evidence from one of AstraZeneca’s witnesses. This clearly established that a rapid drop in prices following generic entry would be difficult, if not impossible, to reverse due to NHS resistance to price rises.
3. Adequacy of damages for the defendant (Glenmark): Glenmark argued that an injunction would cause it incalculable loss, particularly of the first-mover advantage. However, Arnold LJ considered that with at least two other generic companies poised to launch simultaneously, Glenmark’s competitive position was not unique and the loss less significant. The balance of irreparable harm was therefore more evenly matched.
4. Balance of convenience: With uncertainty on both sides regarding the adequacy of damages, Arnold LJ favoured preserving the status quo. He reiterated established appellate authority that when in doubt, the status quo, in this case, AstraZeneca’s exclusivity, should be maintained. This consideration was decisive.

Arnold LJ also acknowledged the "live" judicial debate on whether the American Cyanamid test should be applied more holistically (as discussed by the Irish Supreme Court in MSD v Clonmel in 2019), but affirmed that the English courts remain bound to the established framework and the sequential nature of the test.

Clearing the path and the status quo

Arnold LJ considered that two further points reinforced the decision to preserve the status quo. Glenmark had not “cleared the path” as it had not invalidated the SPC before deciding to launch. Launching “at risk” during or just before trial was described by Arnold LJ as "jumping the gun". 

He also criticised Glenmark’s conduct, noting the significant use of court and party resources required to deal with the urgent application for a short period (between trial and the FOO hearing), which would not have arisen had Glenmark awaited the judgment.

Key takeaways

This judgment illustrates how maintaining the status quo can be important in determining whether to grant interim relief in pharmaceutical patent cases, particularly where market entry by generics could trigger irreversible price erosion. 

Arnold LJ has also clarified that the American Cyanamid test, though binding, is not to be applied mechanistically, and that judicial evaluation of the broader commercial context, including NHS pricing dynamics, is essential when assessing the adequacy of damages. It illustrates how the court should consider the unique facts and circumstances of each case to determine whether an interim injunction is warranted. 

The decision also sends a clear message to generic manufacturers about the importance of "clearing the path" before product launches and ensuring litigation is conducted in a manner that promotes the orderly resolution of disputes. 

Ultimately, the High Court judgment of the first instance trial was handed down on 28 April 2025 and AstraZeneca’s SPCs were invalidated. AstraZeneca has appealed this decision with the Court of Appeal set to hear the case from 25 to 26 June 2025. Following a further application on 28 May 2025, the Patents Court ordered that the interim injunction be continued pending the resolution of the appeal. (Further generic companies were included in this decision). 

Authors: Yasmine Barakat and Heidi Hurdle