On 5 December 2025, the Federal Court of Australia granted an interlocutory injunction restraining the launch and Pharmaceutical Benefits Scheme (PBS) listing of generic long-acting injectable (LAI) paliperidone palmitate products. This breaks a 7-year trend of Australian courts refusing to grant interlocutory injunctions to patentees of pharmaceutical products following Justice Jagot’s landmark decision in Sigma v Wyeth, which demonstrated the complexities that can arise if an interlocutory injunction is wrongly granted.[1] KWM acted for two of the generic companies in that proceeding.
This decision illustrates that – despite the recent trend away from granting applications for interlocutory injunctions – Australian courts will restrain generic launches when satisfied it is appropriate to do so.
Background
Janssen owns an Australian patent, expiring in December 2028, which relates to dosing regimens for sustained release formulations of paliperidone palmitate for the treatment of schizophrenia (the Patent). Janssen’s INVEGA® products are the only LAI paliperidone palmitate products currently available in Australia, with monthly, three-monthly, and six-monthly dosing options.
Juno, a supplier of generic medicines, obtained regulatory approval for two one-monthly paliperidone palmitate products (the Juno Products). It intended to seek PBS listing and supply the Juno Products in Australia.
Janssen alleged that the supply of the Juno Products would infringe three claims of the Patent: a dosing regimen claim, a method of treatment claim, and a Swiss-style claim.
Strong prima facie case of infringement
Justice Burley found that there was a strong prima facie case that the Juno Products, if supplied with their respective product information (PI), would infringe the asserted claims.
This was primarily because the PIs for the Juno Products either mirrored or cross-referenced the dosing regimen in Janssen’s INVEGA® PI, which was found to direct prescribers to administer the products in a manner falling within the scope of the asserted claims.
The Court accepted that in certain scenarios the Juno Products might be used in a non-infringing manner (e.g., in patients with renal impairment or patients switching from other LAI antipsychotics) but considered that these would account for only a small albeit ‘non-trivial’ cohort of patients.
Arguable prima facie case of invalidity
Justice Burley also accepted that there was an arguable prima facie case that the asserted claims are invalid for lack of inventive step and false suggestion. However, his Honour found that these arguments did not rise to a level that would diminish the strength of the prima facie infringement case.
His Honour observed that challenges based on lack of inventive step are ill-suited to resisting an application for an interlocutory injunction, including because assessing the weight of them requires a complex process of fact finding and legal analysis that is difficult to resolve prior to final hearing.[2]
Balance of convenience
Justice Burley then undertook a detailed analysis of the balance of convenience, ultimately finding that it weighed in favour of the grant of an interlocutory injunction. His Honour considered the following factors:
- The strong prima facie infringement case and arguable prima facie invalidity case.
- The fact that an interlocutory injunction would restrain the supply of the Juno Products for various non-infringing uses, that were found to account for a very small cohort of patients.
- The fact that if the interlocutory injunction was not granted, Janssen would suffer very substantial loss of sales and revenue. The Court found that:
- generic entry would likely lead to irreversible voluntary discounting
- this may in turn cause irreversible mandatory PBS price disclosure reductions (although it might take some time for this to occur if Juno were the only generic entrant)
- there was a reasonable possibility other generics would also launch, causing a downward spiral of prices and exacerbating voluntary and mandatory price reductions and
- it is possible (but not likely) that some INVEGA® products would be removed from the market.
- The fact that Juno would lose its ‘first-mover’ advantage as the first generic entrant if the interlocutory injunction was granted. Justice Burley accepted that a first-mover advantage was likely but found that the value and duration of that advantage was speculative.
- The fact that calculating damages owed to Juno (if the interlocutory injunction was wrongly granted) would be more challenging than calculating damages owed to Janssen (if the interlocutory injunction was wrongly refused and Janssen then succeeded at trial). However, Burley J concluded that while this difficulty tends to tilt the scales a little, it does not necessarily equate to ‘uncompensable loss’.
- The fact that Janssen undertook not to launch its own generic and to apply to enjoin any other generics who sought to enter the market during the period of restraint.
Key takeaways
This decision illustrates that Australian courts will grant interlocutory relief to restrain generic launch where the circumstances require. This may be the case even where there is ‘non-trivial’ non-infringing use of the generic product and where there is an arguable challenge to the validity of the patent.
The evidence before the Court will be key to whether an interlocutory injunction application succeeds. It is important to prepare early – as soon as there is a prospect of generic entry on the horizon (for originators) or as soon as an ‘at risk’ launch is contemplated (for generics or biosimilars).
The Court’s decision also illustrates that:
- a strong prima facie case of infringement carries significant weight in the balance of convenience and may not be easily displaced by a complex cross-claim (such as an inventive step challenge)
- for patentees, undertaking to enjoin other generics (and not launch an authorised generic) can be effective in tipping the balance of convenience
- while the Court often gives considerable weight to the complexity of calculating damages if a preliminary injunction were ultimately found to have been wrongly granted, this factor is not insurmountable.
The decision is Janssen Pharmaceutica NV v Juno Pharmaceuticals Pty Ltd [2025] FCA 1538.
Feature image by Gerd Altmann from Pixabay.
[1] Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth [2018] FCA 1556.
[2] Citing Regeneron Pharmaceuticals Inc v Sandoz Pty Ltd [2025] FCA 1067 at [205]–[207] (Rofe J).
