Australia. Preliminary Discovery. A New Frontier… Using PD to Build a Validity Challenge

Generics are now using preliminary discovery in AU to determine whether to mount validity challenges.

Introduction

Preliminary discovery applications are becoming increasingly common in the context of patent disputes in Australia. Typically, they have been deployed by patentees seeking documents to assist in determining whether to commence patent infringement proceedings. We report here on a new frontier in preliminary discovery in patent disputes: the use of preliminary discovery to obtain documents to assist a party to determine whether there are grounds to commence patent revocation proceedings. This is what recently happened in the dispute between Janssen and Juno over a patent relating to dosing regimens for INVEGA® (paliperidone).

Preliminary Discovery: A Primer

Preliminary discovery is a separate cause of action which enables a party to obtain discovery to determine whether it may have a right to obtain relief from a third party.

Rule 7.23 of the Federal Court Rules provides that a party may apply to the Court for a preliminary discovery order if that party:

1. reasonably believes that it may have the right to obtain relief from another;
2. after making reasonable inquiries, does not have sufficient information to decide whether to start a proceeding to obtain that relief; and
3. reasonably believes that:
   1. the other person or entity has (or is likely to have/had) in their control documents directly relevant to whether the first party has a right to the relief; and
   2. inspection of the documents by the first party would assist in making the decision.

The key case about the interpretation of r7.23 (Pfizer Ireland Pharmaceuticals v Samsung Bioepis AU Pty Ltd (2017) 257 FCR 62) (Pfizer) held that:

• rule 7.23 is a beneficial provision, which enables a person who believes they may have a right to relief to obtain information to make a responsible decision as to whether to start proceedings;
• the party seeking PD must prove that it has a reasonable belief that it may (not does) have a right to relief; and
• to defeat a claim for PD, the respondent will need to show, either that the subjectively held belief does not exist, or, that there is no reasonable basis for thinking that there may be (not is) a right to relief such as by demonstrating that no reasonable person, faced with the evidence relied on by the applicant, would think that a right to relief might exist.

Preliminary discovery in patent disputes

Over the past decade, patentees have increasingly used preliminary discovery as a mechanism to obtain documents in the context of brewing patent disputes. The seminal case which started the run of preliminary discovery applications was that of Pfizer in 2017. In that case, Pfizer sought preliminary discovery from Samsung Bioepis and its distributor to enable Pfizer to decide whether to bring an action for infringement of three process patents in respect of pharmaceutical blockbuster Brenzys® (etanercept). On appeal, the Full Federal Court ordered Samsung Bioepis and its distributor to provide preliminary discovery to Pfizer. In making this order, the Full Court made clear the low bar that needed to be met to obtain PD: the applicant must only establish that it reasonably believes that it may have, not has, a right to obtain relief.

Since then, patentees have continued to use preliminary discovery as a means to obtain the vital evidence they need prior to commencing patent infringement proceedings. In some cases, the PD application has been contested.  Some challenges succeeded, but most failed. In many cases, the parties have agreed to provide PD without contest, given the low bar set in Pfizer. Recent examples of preliminary discovery orders made by consent include the litigation between Amgen and Sandoz (now settled) in relation to Prolia®/Xgeva® (denosumab) and the ongoing litigation between Gilead and Alphapharm in relation to Descovy® (Emtricitabine + Tenofovir Alafenamide).

All of the previous PD cases involve the patentee seeking PD to determine whether to commence infringement proceedings. However Juno (an Arrotex subsidiary) has recently turned the tables demonstrating that preliminary discovery can also be used by alleged infringers – here a generic applicant – to obtain documents to assist in determining whether there may be grounds to commence patent revocation/invalidity proceedings.

Janssen filed proceedings against Juno in October 2025 seeking a preliminary injunction (PI) and final relief for alleged threatened infringement of a patent relating to dosing regimens for INVEGA® (long-acting injectable paliperidone esters).  The PI hearing was heard 6 weeks later on 21 Nov 2025, and by judgment delivered 5 December 2025, the court ordered a PI restraining Juno from supplying its generic paliperidone products.   Juno then filed a separate preliminary discovery action 13 May 2026 seeking documents to assist it in determining whether it has grounds to challenge the validity of Janssen’s patent.  Following a hearing on the preliminary discovery action 7 August 2026, the Court on 14 August 2026 ordered patentee Janssen to provide preliminary discovery, including discovery of clinical trial documents. The next step is for Juno to file and serve its Defence and any Cross-Claim within 4 weeks after it receives the documents which Janssen produces pursuant to the preliminary discovery order, which are due to be handed over by 28 September 2026.

Key Takeaways 

This is an interesting strategic “turning of the tables” by a generic company in Australia, and one that we expect to be followed by others.  The take home messages for patent litigants in Australia are:

1. It is extremely easy and straightforward to obtain preliminary discovery in the Federal Court of Australia.
2. Both patentees and alleged infringers can deploy preliminary discovery before commencing substantive proceedings to obtain documents relevant to infringement and invalidity.

About Pearce IP

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Our lawyers and attorneys specialise in pharma, biopharma, biotech, ag-tech, food-tech, med-tech, although our work is broader than these industries.

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