Seeing eye to eye: biosimilar patent case resolved 

What you need to know

• On 27 November 2025, the Full Court of the Federal Court of Australia, by consent of the parties, dismissed Regeneron and Bayer's appeal seeking a preliminary injunction to prevent Sandoz from launching its aflibercept biosimilars.
• Subject to any confidential terms of settlement agreed between the parties, Sandoz may now launch it aflibercept biosimilars in Australia.

Regeneron Pharmaceuticals, Inc. & Ors v Sandoz Pty Ltd

Regeneron holds an Australian patent for a dosing regimen for aflibercept (Patent). Aflibercept is sold by Bayer under the brand name EYLEA® and is used to treat angiogenic eye disorders. Regeneron and Bayer sought urgent interlocutory orders restraining Sandoz from marketing, importing and engaging in activities relating to the launch of its aflibercept biosimilar AFQLIR®, and requiring Sandoz to take reasonable steps to withdraw its application to list its aflibercept products on the Pharmaceutical Benefits Scheme (PBS).

At first instance Justice Rofe dismissed the application, concluding that: (1) Regeneron and Bayer had not established a strong prime facie case on infringement; and (2) the balance of convenience did not favour the granting of injunctive relief.

Strong prime facie case on infringement not established

Justice Rofe found that the Sandoz product information did not instruct or induce use of the products in an infringing manner, and that Sandoz would not have a reason to believe that the products would be used in an infringing manner.

The dispute on infringement turned on a question of construction: whether an instruction to administer the product one or two months after the preceding dose amounts to an instruction to administer the product 4 weeks or 8 weeks after the preceding dose, respectively. Her Honour considered that the consistent use of "weeks" throughout the Patent specification was a deliberate choice by the patentee to use a more precise dosing regimen, that 4 weeks is not equivalent to one month, and that 8 weeks is not equivalent to 2 months. These findings, coupled with evidence that many doctors follow their own dosing regimen, led her Honour to conclude that there is a real prospect that the use of the Sandoz products will not infringe the Patent.  

Sandoz cross-claimed that the Patent is invalid due to lack of novelty, inventive step and support, however her Honour did not consider that any of these grounds were persuasive.

Balance of convenience favours no preliminary injunction

Justice Rofe considered several factors in weighing up the balance of convenience, including:

1. a PBS mandatory price reduction of at least 25% and its potential global impact (including in the United States, due to its Most Favoured Nation drug policy, and in Taiwan, due to international reference pricing);
2. the shift of the market for aflibercept products away from the status quo, due to Regeneron and Bayer transitioning the market for their EYLEA® 2mg product to their EYLEA® 8mg product and the increasing market share of a third party product VABYSMO®;
3. the loss of Sandoz's first mover advantage, which her Honour considered particularly relevant due to the idiosyncrasies of the aflibercept biosimilar market (including high barriers of entry and evidence that once a patient is switched to a biosimilar, they are unlikely to be switched to another);
4. the disproportionate nature of the broad relief sought, in light of her Honour's view on non-infringing use; and
5. the difficulties in quantifying damage.

Her Honour stated that the assessment of all the parties' loss and damage is complex, time consuming and subject to uncertainty. However, her Honour concluded that the greater number of unknowns arising from an injunction being granted suggests it would be more difficult to calculate Sandoz's loss. In comparison, her Honour considered that the loss suffered by Regeneron and Bayer if no preliminary injunction was granted is principally loss of revenue, and is likely to be compensable by a damages award.

Settlement on the eve of the Full Court's decision

Regeneron and Bayer appealed Justice Rofe's decision to the Full Federal Court. The appeal was heard in October 2025. The Full Court was initially due to hand down its judgment on 20 November. This was postponed to 26 November, and then the matter was dismissed by consent of the parties. Related Federal Court proceedings between the parties have also been dismissed by consent.

The Full Court's decision had been eagerly anticipated by those working in pharmaceutical patent litigation. With Justice Rofe's reasoning to stand, all eyes will now turn to whether Sandoz's aflibercept products achieve PBS listing and launch in the coming months.

Authors: Stuart D'Aloisio, Partner; Daele Tyler, Senior Associate and Nikola Cinque, Associate.