Never a Drought: AstraZeneca’s Preliminary Injunction Dispels the Mirage

Summary

In a recent article, we rebutted suggestions of a seven-year preliminary injunction drought in pharmaceutical patent cases in Australia and discussed the Federal Court’s consistent application of an orthodox approach to assessing whether to grant a preliminary injunction in such cases. Justice Downes’ decision in AstraZeneca AB v Pharmacor Pty Ltd [2026] FCA 88 (AstraZeneca AB v Pharmacor), granting a preliminary injunction by applying the orthodox approach, further quenches any suggestions of a drought.

 

Background

AstraZeneca sued Pharmacor on 17 December 2025 for infringing its dapagliflozin patent, which was not due to expire until 22 October 2027 (AZ Patent). AstraZeneca sought an urgent interlocutory injunction to prevent Pharmacor from listing its generic dapagliflozin products on the Pharmaceutical Benefits Scheme (PBS) from 1 April 2026. The case was heard urgently on 6 February 2026 because the cut‑off date for withdrawal of Pharmacor’s PBS listing application was imminent (18 February 2026). Judgment was delivered by Justice Downes on 16 February 2026 granting the requested preliminary injunction.

 

Prima Facie Case

There was no dispute that Pharmacor’s products would infringe claims 1 and 2 of the AZ Patent, if valid. Accordingly, the interlocutory dispute focused on whether Pharmacor’s invalidity case was sufficiently strong to undermine AstraZeneca’s prima facie case on infringement. Pharmacor challenged the validity of the AZ Patent on three grounds: lack of novelty, lack of inventive step and lack of manner of manufacture. 

Prior Art

All three invalidity grounds hinged on PCT international application publication WO 01/27128 (WO 128 prior art), disclosing a broad class of C-aryl glucoside SGLT2 inhibitors via generic formulae that arguably encompassed dapagliflozin among millions of compounds.

Selection Patents

Key to Pharmacor’s invalidity case was its contention that UK “selection patent” principles form part of Australian law. Justice Downes addressed this during her Honour’s analysis of novelty. After reviewing a number of Australian decisions that have considered selection patent principles, her Honour was not persuaded, for the purpose of the preliminary injunction application, that those UK principles form part of Australian patent law.

Invalidity

On this basis, Justice Downes assessed each alleged invalidity ground using orthodox Australian principles. On lack of novelty (requiring clear and unmistakable directions), her Honour considered the WO 128 prior art lacked specific disclosure, enablement, or direction to make dapagliflozin among millions of compounds. On lack of inventive step, her Honour considered the WO 128 prior art offered no obvious path to dapagliflozin and that the contested expert evidence was unfit for interlocutory resolution. On lack of manner of manufacture, her Honour considered this requirement was met by the patent’s disclosure of a new compound, therapeutic uses (e.g., hyperglycaemia), and manufacturing methods, beyond mere arbitrary selection.

Justice Downes concluded that Pharmacor’s invalidity grounds were arguable but did not diminish the strength of the prima facie case on infringement.

 

Balance of Convenience

Having found AstraZeneca established a strong prima facie case on infringement, Justice Downes assessed whether the balance of convenience favoured a preliminary injunction.

Irreparable Harm to AstraZeneca

Justice Downes considered the impact of early generic entry on the value of AstraZeneca’s property rights in the AZ Patent. Her Honour held that premature generic entry would irreversibly diminish, if not destroy, the value of those rights. Once exclusivity was lost, the benefit of the monopoly could not be restored, even if AstraZeneca ultimately succeeded at trial, and thus AstraZeneca would suffer irreparable harm.

Her Honour held that allowing Pharmacor to PBS list its generic dapagliflozin products on 1 April 2026 would likely trigger an immediate statutory price reduction, followed by aggressive discounting leading to further statutory price reductions, causing significant revenue loss for AstraZeneca for the remainder of the patent term.

Justice Downes also accepted that, if unrestrained, Pharmacor would secure a significant first‑mover advantage on the PBS. It was common ground that AstraZeneca could not list an authorised generic before Pharmacor’s PBS listing on 1 April 2026, with the earliest possible listing date being 1 May 2026. Pharmacor would therefore be the sole generic dapagliflozin supplier for at least one month. During that period, discounted forward‑selling, combined with a three‑year shelf-life, would enable pharmacies to stockpile product and dampen demand for later generic entrants.  

While AstraZeneca could mitigate some loss by launching an authorised generic one month later, her Honour accepted that this would require deploying that strategy more than 18 months before patent expiry. Doing so would generate limited generic profits while accelerating a significant decline in sales and volumes of its originator and combination products.

In those circumstances, AstraZeneca would suffer irreparable harm.

Consequences of Granting an Injunction

Justice Downes also carefully considered the prejudice to Pharmacor if it were restrained. Her Honour acknowledged that Pharmacor would suffer substantial commercial loss, particularly through the loss of first‑mover advantage and the difficulty of quantifying its damages.  

AstraZeneca Undertakings

AstraZeneca agreed to provide the usual undertaking as to damages, undertaking to compensate Pharmacor and any affected third parties, including the Commonwealth, for loss suffered should it later be found that the preliminary injunction had been wrongly granted.  

AstraZeneca provided additional undertakings requested by Pharmacor to mitigate potential prejudice if a preliminary injunction were to be granted. These undertakings required AstraZeneca to:

• notify Pharmacor of any third party intending to exploit dapagliflozin products before patent expiry;
• promptly commence interlocutory proceedings against any such party to enforce the AZ Patent;
• not launch or authorise an authorised generic while Pharmacor remained restrained; and
• prosecute the substantive proceeding expeditiously.

Justice Downes placed significant weight on these undertakings in assessing the balance of convenience, noting that they were comprehensive, addressed the concerns raised by Pharmacor, and that no undertakings sought by Pharmacor had been refused.

In light of AstraZeneca’s strong prima facie case of infringement, which was not undermined by Pharmacor’s validity attacks, the above considerations on the balance of convenience, including the undertakings offered by AstraZeneca, and the fact that the matter is expedited for trial in August 2026, her Honour concluded that the balance of convenience favoured granting the preliminary injunction.

 

Consideration

Expected victory

AstraZeneca’s success was expected having regard to Pharmacor’s case. It is generally accepted that invalidity arguments that involve a complex process of fact finding and legal analysis are inappropriate for interlocutory determination. 

This is especially true for preliminary injunctions relating to pharmaceutical patent infringement.  In past cases, the success of a party in resisting a preliminary injunction has been based on a strong invalidity case which almost decisively demonstrates that the patent in suit is invalid. For example, in respect of the semglee case, the court concluded that there was sufficiently strong prospects that two prior art documents anticipated all of the features of the asserted claims of the patent in suit. Pharmacor’s decision to advance an invalidity case that requires a determination that a niche aspect of UK patent law has formed part of Australian patent law and a lack of inventive step case involving competing expert evidence are matters requiring a complex process of fact finding and legal analysis. Such matters are apt for determination at trial, not on an interlocutory basis.

Public interest

In deciding to grant the preliminary injunction, Justice Downes also expressly acknowledged the public interest from the generic and the innovator perspectives. On the one hand it is in the interests of the Commonwealth and the public for dapagliflozin to be sold at a lower price, which weighed against the grant of a preliminary injunction. However, the countervailing argument, which has in recent times been overlooked, is the public interest in the confidence in the Australian patent system. Patents confer a statutory monopoly intended to encourage innovation and the failure to restrain a party from exploiting generic products in the circumstances of the case risks depriving innovators of the practical benefit of that monopoly. This, in turn, could undermine the patent system in Australia, with a consequential negative impact on future research and development and on the licensing of patented pharmaceutical products in Australia.