Australian generics turn preliminary discovery into patent validity tool

Generic drug companies are using preliminary discovery in Australia to investigate whether they have grounds to challenge the validity of pharmaceutical patents, in a potentially significant development for patent litigation strategy.

The issue arose in proceedings involving Janssen and Juno Pharmaceuticals concerning a patent covering dosing regimens for INVEGA, Janssen’s long-acting injectable paliperidone product.

According to Australian IP firm Pearce IP, Juno has used preliminary discovery to obtain documents from Janssen that could help it determine whether to bring a patent revocation action.

The development represents a reversal of the more traditional use of preliminary discovery in patent disputes, where patentees have sought information from potential infringers to determine whether they have grounds to commence infringement proceedings.

Turning the tables

Preliminary discovery is available under Rule 7.23 of the Federal Court Rules 2011 (Cth). It allows a prospective applicant to seek documents from a prospective respondent where the applicant reasonably believes it may have a right to obtain relief but does not have sufficient information, after making reasonable inquiries, to decide whether to commence proceedings.

The relatively low threshold means the procedure can provide a route to obtaining evidence before substantive litigation is commenced.

Historically, this mechanism has been used by patent owners seeking to establish whether another party is infringing their rights.

The Janssen-Juno dispute demonstrates that the mechanism can operate in the opposite direction, with an alleged infringer seeking information to assess a potential validity challenge.

Janssen and Juno dispute

Janssen commenced proceedings against Juno in October 2025, seeking a preliminary injunction and final relief concerning Juno’s proposed generic paliperidone products.

The dispute concerned patent rights relating to dosing regimens for long-acting injectable paliperidone esters used in connection with INVEGA.

In December 2025, the Federal Court granted Janssen an interlocutory injunction restraining Juno from supplying its generic paliperidone products pending the outcome of the litigation. The court found that Janssen had established a strong prima facie case of infringement, while Juno’s arguments concerning invalidity were considered arguable but not strong enough at the interlocutory stage to prevent the injunction.

Juno subsequently took a different procedural route.

On May 13, 2026, it commenced a separate preliminary discovery proceeding seeking documents that could assist it in determining whether it had grounds to challenge the validity of Janssen’s patent.

Following a hearing on August 7, the Federal Court on August 14 ordered Janssen to provide preliminary discovery, including documents relating to clinical trials.

Janssen is due to provide the ordered documents by September 28, after which Juno is expected to file and serve its defense and any cross-claim within four weeks.

Potential strategic significance

The development could have broader implications for pharmaceutical patent litigation in Australia.

For generic companies facing an infringement claim, the ability to obtain relevant documents before committing to a formal revocation challenge could help inform decisions about whether and on what grounds to attack a patent.

It could also allow alleged infringers to investigate evidence that may not otherwise be available to them at an early stage of proceedings.

Pearce IP described the case as a “new frontier” for preliminary discovery and said it expected other generic companies to follow the approach.

The firm also highlighted the relatively low threshold for obtaining preliminary discovery in the Federal Court, noting that an applicant needs to establish only that it reasonably believes it may have a right to obtain relief, rather than demonstrating that it already has an established cause of action.

A two-way litigation tool

The development is notable because preliminary discovery is no longer simply a mechanism for patentees seeking to identify potential infringement.

The Juno proceedings demonstrate how the procedure can potentially be deployed by both sides of a patent dispute: rights holders can use it to investigate infringement, while alleged infringers can seek evidence relevant to potential invalidity or revocation proceedings.

That could give generic companies an additional procedural tool when assessing whether to challenge pharmaceutical patents, particularly where important validity evidence is held by the patent owner.

For patent litigators, the case therefore provides an important reminder that preliminary discovery can play a role not only in establishing infringement claims, but also in developing the case for a potential validity challenge.

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