In a significant development for antibody patent protection in Australia, the Federal Court has dismissed Sanofi's appeal against Amgen's PCSK9 antibody patents and ordered that Amgen's patent applications for its cholesterol-lowering drug Repatha (evolocumab) proceed to grant.
The ruling marks another chapter in the global patent litigation concerning Amgen's PCSK9 antibody patents, which has seen divergent outcomes across major jurisdictions. While Amgen's claims were invalidated in the US for lack of enablement and in Europe for lacking inventive step, the Australian Federal Court has now upheld the validity of Amgen's patent applications.
Australian Decision Contrasts with US Supreme Court Ruling
Justice Nicholas's decision in Australia stands in stark contrast to the unanimous ruling by the US Supreme Court, which invalidated Amgen's patents covering Repatha. The US justices concluded that Amgen failed to "enable any person skilled in the art to make and use" the invention, stating: "the more a party claims, the broader the monopoly it demands, the more it must enable."
The Australian decision was made under the Patents Act 1990 prior to the introduction of the "Raising the Bar" amendments that came into effect in 2013, which significantly raised written description requirements to align with international standards. Under the pre-amendment Act, the requirements of "full description" and "fair basis" apply, which set a lower standard than the current "support" and "sufficiency" requirements.
Key Patent Claims and Opposition Grounds
Amgen's patent applications cover three classes of claims:
- Epitope claims defining antibodies by their ability to bind an epitope of PCSK9
- Residue claims defining antibodies by their ability to bind specific residues of PCSK9
- Competition claims defining antibodies by their ability to compete with structurally-defined antibodies
Sanofi challenged these applications on multiple grounds, including failure to define the invention, lack of manner of manufacture, lack of fair basis, lack of clarity, failure to describe the invention fully, and lack of inventive step.
The Court rejected all grounds of opposition, finding that the functional limitations in the claims were sufficient to characterize the construction of the relevant monoclonal antibodies, enabling skilled persons to determine whether any particular antibody falls within the scope of the claims.
Implications for Antibody Patents in Australia
Dr. Duncan Bucknell, patent attorney and Managing Director at Spruson & Ferguson, commented on the significance of the ruling: "This decision holds important lessons for a number of other valuable antibody patents that are approaching the end of their term and that are still subject to the old Act – and that may be the target of litigation in coming years as biosimilars look to enter the market."
The case highlights the critical differences between Australia's pre-2013 patent law and the current standards. Under the old law, establishing "fair basis" required only that the body of the specification contain "a real and reasonably clear disclosure" of what is claimed, without concern for the technical contribution to the art or inventive merit.
Commercial Context
Repatha (evolocumab) targets PCSK9 and lowers low-density lipoprotein (LDL) cholesterol levels. It was first approved by the Australian Therapeutic Goods Administration in 2015 for the treatment of hypercholesterolaemia. Sanofi and Regeneron's competing product, Praluent (alirocumab), also targets PCSK9.
The PCSK9 inhibitor market has become increasingly competitive, with Amgen reporting $1.3 billion in global Repatha sales last year, while Regeneron made $130 million from Praluent in the US and Sanofi booked $400 million in sales from ex-US markets.
Next Steps
The Court has given the parties until May 21, 2025, to apply for leave to appeal the decision. If Amgen's applications proceed to grant, they may also be eligible for an extension of term based on the regulatory approval of evolocumab.
This ruling demonstrates the complex and often contradictory landscape of global patent protection for biologic drugs, with outcomes varying significantly by jurisdiction despite similar underlying technologies and patent claims.
