Co-author: Dr James Burnley, Senior Associate and David Longmuir, Principal
Previously, PIs were routinely granted to pharmaceutical patentees on the basis that the mandatory price reduction, triggered by the first generic entry listing, weighed strongly in favour of the granting of an injunction. However, since 2018, the Court has taken a different approach, refusing the grant of PIs in pharmaceutical cases. Indeed, as recently September 2025, the Court either found that there was not a strong enough prima facie case for infringement,[1] and/or that the difficulty in calculating damages suffered by a generic restrained by a PI on a patent that was ultimately found invalid,[2] shifted the balance of convenience against the grant of interim injunctive relief.
Both Pharmacor and Janssen demonstrate the importance of an originator’s prima facie case for infringement (and the strength of the case for invalidity) to the balance of convenience.
The prima facie infringement case
While it did not dispute infringement, Pharmacor argued there was a strong case for invalidity of AstraZeneca’s patent, for lack of novelty and inventive step, which qualified the prima facie case of infringement.
However, Downes J rejected Pharmacor’s arguments, noting that the authorities relied upon for novelty were not established Australian law and needed to be examined at trial. Downes J also noted that the ground of inventive step “is ill suited to the objective that Pharmacor seeks to attain, which is to demonstrate weakness in the prima facie case of infringement asserted against it”,[3] stressing that the credibility of expert evidence couldn’t be properly assessed in the absence of cross-examination. Similarly, in Janssen, while Juno submitted that the relevant claims were invalid for lack of inventive step and false suggestion, Burley J concluded that, although arguable, these arguments did not “rise to the level that it diminishes the strength of the infringement arguments”.[4] Mirroring the concerns of Downes J, Burley J observed that inventive step and false suggestion attacks require complex evidence and legal analysis that is ill suited to interlocutory resolution.
In both cases, the Court recognised that generic entry could trigger market changes and long-term pricing consequences prejudicing the patentee, and these changes may be difficult to unwind and calculate. Although it was considered likely that Pharmacor and Juno would both suffer some loss of first mover advantage by granting of a PI, which would also be difficult to quantify, this was at least partially addressed by undertakings from the originators to not launch their own generics. Ultimately, the strong and undiminished prima facie infringement cases tipped the balance of convenience in favour of both AstraZeneca and Janssen.
Key insights
These decisions may be the start of an encouraging trend for originators seeking to restrain generics from entering the market. They also provide a guide for originators seeking PIs, reinforcing the importance of a strong prima case of infringement (which may not be weakened by a complex invalidity attack).
Importantly, the obstacles caused by the difficulty of assessing damages flowing from a PI wrongly granted can be overcome, and a patentee can shift the balance of convenience towards the granting of a PI by offering appropriate undertakings, such as not to launch an authorised generic.
Timing is critical
In Pharmacor, AstraZeneca commenced proceedings shortly after Pharmacor entered its products onto the Australian Register of Therapeutic Goods (ARTG). The interlocutory application was heard less than two months later, ahead of the deadline for Pharmacor to withdraw its PBS listings.
This short timeframe must be taken into account when developing an enforcement strategy in Australia – the expert and market evidence before the Court will be crucial to the outcome.
[1] Regeneron Pharmaceuticals Inc v Sandoz Pty Ltd [2025] FCA 1067; Biogen International GmbH v Pharmacor Pty Ltd [2021] FCA 1591
[2] Abbey Laboratories Pty Ltd v Virbac (Australia) Pty Ltd [2024] FCA 1488; Sanofi-Aventis Deutschland GmbH v Alphapharm Pty Ltd (No 3) [2018] FCA 2060
[3] AstraZeneca AB v Pharmacor Pty Ltd [2026] FCA 88 at [67]
[4] Janssen Pharmaceutica NV v Juno Pharmaceuticals Pty Ltd [2025] FCA 1538 at [202]
