Janssen v Juno rains on claims of a preliminary injunction drought

Summary

In this article, we discuss why allusions by some commentators to a seven-year preliminary injunction drought in pharmaceutical patent cases are illusory and how the Federal Court’s decision in Janssen Pharmaceutica NV v Juno Pharmaceuticals Pty Ltd [2025] FCA 1538 (Janssen v Juno) to grant a preliminary injunction confirms the court’s orthodox approach to assessing whether or not to grant a preliminary injunction in such cases.

 

Introduction

In Australia, preliminary (or interlocutory) injunctions serve as a critical tool for pharmaceutical innovators seeking to temporarily block generic and biosimilar entrants pending resolution of patent infringement disputes. The patentee must demonstrate a prima facie case of infringement of valid claims in the sense that if the evidence remains as it is there is a probability that at the trial it will obtain the injunctive relief sought, and that the balance of convenience favours such injunctive relief. The strength of the prima facie case is an important consideration to be weighed in the balance of convenience.

 

A perceived shift after 2018?

For years leading up to 2018, innovators enjoyed a strong track record in securing these injunctions to maintain market exclusivity during litigation. Since 2018, however, a narrative emerged of heightened judicial caution in granting preliminary injunctions. This appeared to stem from the court’s first decision regarding claims on undertakings as to damages against innovators whose preliminary injunctions were later overturned, and the first preliminary injunction decision following this. These cases brought attention to the complexities of quantifying compensation not just for generics but for the government. Commentators have since pointed to this as tilting the balance against patentees, making courts appear reluctant to restrain generic launches.

However, in the supposed seven-year drought between Justice Burley’s decision granting a preliminary injunction to restrain launch of a biosimilar to rituximab in mid-2018 and his decision granting a preliminary injunction in Janssen v Juno, the court denied preliminary injunctions in only three pharmaceutical patent cases (which we discuss further below). Moreover, Justice Burley’s decision in Janssen v Juno effectively further debunked the narrative and confirmed that the court’s approach to preliminary injunctions had remained essentially the same.

 

Dissecting the “drought”

A closer examination of the Rituximab case and the three pharmaceutical preliminary injunction cases between that case and Janssen v Juno reveals no doctrinal pivot by the court:

Molecule	Preliminary injunction	Prima facie case	Balance of convenience
Rituximab (2018)	Granted	Infringement was admitted, and thus the patentee had a strong prima facie on infringement. The respondent’s invalidity case on lack of inventive step was held (at the provisional level) to be arguable, but not sufficient to undermine the patentee’s strong prima facie case on infringement.	The balance of convenience tipped in favour of the patentee. Key considerations, in addition to the strength of the prima facie case, included: launch of a rituximab biosimilar would cause losses to the patentee that could not be adequately calculated or compensated by an award of damages (e.g. a 16% statutory price reduction by the PBS, loss of market share, loss of goodwill etc). A competitor’s launch of another rituximab biosimilar was imminent. Complexities of record keeping (and thus, calculation of damages) would be difficult and exacerbated with another biosimilar entrant. The first mover advantage was hard to quantify and predict, particularly given the competitor’s biosimilar was set to launch within months of the respondent’s product. Market penetration of biosimilars is slow.
Semglee (2018)	Refused	The patentee had a strong prima facie case on infringement, however, the respondent’s invalidity case based on lack of novelty was sufficiently strong (at the provisional level) to undermine the patentee’s case on infringement.	The balance of convenience was evenly balanced but tipped in favour of the respondent. Key considerations, in addition to the strength of the prima facie case, included: Following a very detailed discussion of the complexities of the calculation of loss if a preliminary injunction was granted relative to if it was denied, informed by the court’s recent first decision regarding claims on an undertaking as to damages, the court concluded that in relative terms the harm suffered by the generic should an injunction be granted will be significant and less readily compensated by an award of damages than for the patentee, if an injunction is not granted. The court also concluded, having regard to the relative complexities between the two, that the calculation of loss likely to be suffered by the generic is likely to be more difficult than the calculation of loss for the patentee.  The patentee had launched an improved product, which would destabilise the market into which the respondent sought to launch its product such that the market would be very different (and likely much smaller) to its current state. Although there was another competitor product registered on the Australian Register of Therapeutic Goods (ARTG) and received positive recommendation for its product from the PBAC, the competitor had taken no steps to bring its product to the market for a number of years.
Dimethyl fumarate (2021)	Refused	Infringement was admitted, however, the court found the patentee’s prima facie case to be weak in light of its provisional view that the extension of term of the patent in suit was wrongly granted.	The balance of convenience factors between the parties were quite evenly balanced, including that the calculation of loss if a preliminary injunction was granted and if it was denied were of comparable complexity. However, the balance tipped in favour of the respondent as the patentee had launched an improved product, which would destabilise the market into which the respondent sought to launch its product such that the market would be very different (and likely much smaller) to its current state.
Aflibercept (2025)	Refused	Respondent had a serious non-infringement argument based on construction of the claims and a strong invalidity case based on lack of novelty, lack of inventive step and lack of support. The court held (at the provisional level) that the patentee had not established a strong prima facie case on infringement.	The balance tipped in favour of the respondent. Key considerations, in addition to the strength of the prima facie case, included: Widespread infringing use was unlikely to be established even if the patentee were to succeed at trial. The patentee had launched an improved product, which would destabilise the market into which the respondent sought to launch its product such that the market would be very different (and likely much smaller) to its current state. Loss of first mover advantage to the respondent: unlike generic small molecules, patients are very unlikely to be switched between biosimilars. higher barriers of entry and constraints of any biosimilar in gaining market share.

 

Janssen v Juno

On 5 December 2025, Justice Burley granted Janssen a preliminary injunction, restraining launch of Juno’s proposed generic paliperidone palmitate long-acting injectable products.

 

Prima facie case

Justice Burley found that Janssen had established a strong prima facie infringement case. His Honour considered Juno’s invalidity case to be arguable based on lack of inventive step and false suggestion, but deemed them ill-suited for interim resolution and insufficient to undermine Janssen’s strong prima facie case on infringement.

 

Balance of convenience

Justice Burley undertook a comprehensive assessment of where the balance of convenience lay, ultimately concluding it favoured restraint of Juno’s entry.

Substantial loss of sales and revenue:  Justice Burley held that if a preliminary injunction was not granted, Janssen would suffer a very significant loss of exclusivity leading to a very substantial loss of sales and revenue.

Unlike the typical scenario in which first generic listing on the PBS triggers an immediate statutory price reduction, as Janssen’s products had already endured anniversary reductions, including a 26.1% cut on 1 April 2023 under F1 formulary rules, generic listing would not trigger an immediate statutory price reduction. However, a first generic listing would still shift Janssen’s products to the F2 formulary, triggering price disclosure obligations and exposing Janssen’s product to future automatic statutory price disclosure price reductions as a result of voluntary discounting.

His Honour accepted that Janssen would be required to make voluntary discounts to its products to remain competitive if Juno entered the market – discounts that are unlikely to be reversible. His Honour also accepted the possibility of Janssen withdrawing certain products due to lost sales, plus the reasonable prospect of further generics entering the market before patent expiry, causing a downward price spiral as a result of further competitive voluntary price reductions by all parties in the final years of exclusivity.

His Honour noted that such voluntary price reductions may in turn cause mandatory and irreversible automatic statutory price disclosure price reductions (although this would not occur for at least 12 months post-first generic entry, with the patent expiring December 2028).

First mover advantage: Two further generic competitors have products registered on the ARTG, and each confirmed with Janssen that they had no present intention to launch their respective products, but that this position may change. While this did not permit firm conclusions as to the likelihood that each would enter the market, Justice Burley accepted that there is a possibility that either or both will apply to PBS list their products prior to patent expiry. Justice Burley also accepted that the first generic supplier of an established pharmaceutical product is likely to have competitive advantages over later generic entrants. However, his Honour noted that assessment of the value and duration of this first mover advantage in advance is speculative, particularly when launch of further generic competitors could also be imminent. His Honour also noted that the first mover advantage that Juno sought was in relation to products that on the evidence presented were likely to be infringing.

Janssen countered the effect on Juno of losing its first mover advantage by offering the following undertakings – if Juno were to be restrained, Janssen would notify and take steps to enjoin any other generic if they sought to list on the PBS, and Janssen would itself not launch an authorised generic during the period of restraint. Justice Burley considered Janssen’s undertaking to be material in countering the effect of Juno losing its first mover advantage.

Damages calculation: Justice Burley concluded on the evidence that it would be more difficult to calculate a fair assessment of damages to Juno on the undertaking as to damages on a restraint scenario in comparison to calculating damages to Janssen consequent of any finding of infringement in a non-restraint scenario.

Although this shifted the scales slightly to favour Juno, his Honour concluded that difficulty in calculation does not necessarily equate to uncompensable loss. A key consideration that his Honour took into account was the undertaking offered by Janssen to not launch its own generic and to enjoin any other generic seeking to list on the PBS should Juno be restrained.

 

Consistency over change: the enduring test

In each of the above cases where a preliminary injunction was refused, the patentees fell short on the merits. Each court’s assessment in deciding to refuse a preliminary injunction was based on the same orthodox approach of assessing the strength of the prima facie case (each court concluding that the patentee had failed to establish a strong prima facie case) and engaging in a weighing process to evaluate where the balance of convenience lies. Janssen v Juno reaffirmed this approach.

Juno had attempted to circumvent this approach by urging his Honour to ignore the strength of the prima facie case, confining the assessment to the balance of convenience. His Honour disagreed with the approach, citing precedent which accepted that the strength of the prima facie case is relevant to the balance of convenience. In particular, the weighing process involved in evaluating where the balance of convenience lies does not affect the assessment of the existence or strength of the prima facie case. What is required is for the court to assess the strength of the probability of ultimate success on the part of the patentee. It is from there that assessment is made of the practical consequences of what may likely flow from the grant of the injunction sought.

 

Key takeaways

The narrative of a seven‑year preliminary injunction “drought” in pharmaceutical patent cases does not withstand scrutiny. The decisions since 2018 reflect the court’s consistent application of the orthodox test, involving a careful, evidence‑based analysis of the strength of the prima facie case and of the balance‑of‑convenience, rather than any shift in principle. Janssen v Juno makes this clear, reaffirming that well‑prepared patentees can still secure interlocutory relief where the merits and the commercial realities justify it.

For patentees, the practical message is straightforward: preliminary injunctions remain a viable and effective tool.

For patentees, important considerations continue to include:

• early monitoring of potential competitor entrants;
• establishing a strong prima facie case of infringement of a valid claim;
• factors which would destabilise the market (e.g. introduction of an authorised generic, biosimilar or biobetter to shift the existing market); and
• factors which would preserve the market (e.g. offering robust undertakings to manage competitive harm).

The court assesses whether to grant a preliminary injunction on a case-by-case basis. The evidence presented to the court continues to be key to whether an interlocutory injunction will be granted. For patentees, preparation should begin as soon as there is a suspicion that a generic or biosimilar may seek marketing authorisation to launch in Australia.