In Sun Pharma ANZ Pty Ltd v Otsuka Pharmaceutical Co Ltd [2025] FCA 44 (‘Sun Pharma’), the Federal Court of Australia considered the validity of a patent term extension (PTE) granted to Otsuka for its controlled release aripiprazole injection. Although the Court ultimately held the relevant claims to be invalid for lack of clarity and definition contrary to ss 40(2)(b) and 40(3) of the Patents Act 1990 (Cth), the judgment offers useful guidance on the requirements of PTEs.  The judgement also confirms that product claims with a process limitation or limitation by result, and kit claims, can be eligible for PTE.

Building on the reasoning in Cipla Australia Pty Ltd v Novo Nordisk A/S [2024] FCA 1414 (‘Cipla’), which we discussed in a previous article, Sun Pharma further clarifies the requirements of s 70 of the Patents Act. The case confirmed that a “pharmaceutical substance” under s 70(2)(a) can include a formulation and need not be in a ‘ready to use’ form—meaning that certain kit claims may be eligible. The Court also held that the inclusion of process or ‘in-use’ features in a pharmaceutical substance claim does not necessarily preclude PTE eligibility. Additionally, it was clarified that a pharmaceutical substance must take all of the integers of a claim to qualify for a PTE.

Finally, the Court also confirmed that the form of the goods registered on the Australian Register of Therapeutic Goods (ARTG) is irrelevant for the purposes of s 70(3) assessment; what matters is that the pharmaceutical substance is an ingredient of the goods.

‍Background

The case involved Otsuka’s Australian Patent No. 2004285448 relating to controlled release aripiprazole formulations used in the treatment of schizophrenia and bipolar I disorder.

The claims of the patent relate to two types of aripiprazole formulations:

• ready to use controlled release injectable formulations; and
• freeze-dried controlled release formulations that must be reconstituted prior to injection.

The claims also include the features of aripiprazole having a mean particle size of about 1 to 10 microns and “which upon injection releases aripiprazole over a period of [a specified time]”.

The patent’s term was extended to 25 July2029 after Otsuka sought and was granted a PTE based on the inclusion of ABILIFY MAINTENA on the ARTG. ABILIFY MAINTENA products are kits comprising a vial of freeze-dried aripiprazole powder and a separate vial of solvent.

Sun Pharma, which is intending to launch a generic version of ABILIFY MAINTENA, challenged the validity of the PTE and sought rectification of the Register, arguing that the pharmaceutical substances per se, nor the claims on which they are predicated, meet the requirements of s 70.

Reasoning and Decision

Validity of PTE

In assessing the validity of the PTE, Justice Downes provided valuable guidance on the interpretation of the s 70 provision.

At [99], based on her analysis of relevant authorities, her Honour summarised what constitutes a pharmaceutical substance per se:

‍"The following emerges from these authorities for the purposes of identifying a claim for a pharmaceutical substance per se (which are not mutually exclusive):

‍(1)              only a claim for a pharmaceutical substance as such or alone will qualify;

(2)              a pharmaceutical substance which forms part of a method or process does not qualify;

(3)              an existing pharmaceutical substance prepared by a new and inventive process does not qualify;

(4)              a pharmaceutical substance when produced by a particular process (product by process claim) does not qualify;

(5)              a new and inventive method of using an existing pharmaceutical substance (such as in a new method of treatment) does not qualify.  This could extend to a new and inventive pharmaceutical method of delivery."

Sun Pharma advanced that the claims are not to a pharmaceutical substance because they include process or in use features (i.e.“controlled release”, “injectable formulation”, “which upon injection releases aripiprazole over a period of [a specified period of time]”), which limit the use of the formulations. Furthermore, that the patent claims a process or method of an existing pharmaceutical substance. However, Her Honour disagreed,noting that the claims “refer incidentally to methods or process, but they do so in order to better describe the new and inventive substance, being the claimed injectable or freeze-dried formulations”.

The Court has also affirmed the decision in Cipla, which found that the definition of “pharmaceutical substance” includes formulations. In particular, that Justice Perram’s interpretation of the word “application” as meaning the “use to which the substance is put” is correct. For these reasons, her Honour rejected Sun Pharma’s contentions that the claimed formulations do not qualify as pharmaceutical substances because they are formulations, contain excipients, and in the case of the freeze-dried formulations, they cannot be ‘applied’ so as to involve “a chemical interaction or physico-chemical interaction, with a human physiological system” because they need to first be reconstituted with water to form injectable (liquid) formulations.

Sun Pharma also contended that the requirements of s 70(3) are not met because the ABILIFY MAINTENA products,which contain separate vials of freeze-dried powder and solvent do not contain the pharmaceutical substance (i.e. the ready to use formulation). In this regard, her Honour referred to the decision in Novartis AG v Pharmacor Pty Limited (No 3) [2024] FCA 1307 and clarified that the correct approach in a s 70(3)(a) inquiry is:

“a simple comparison of the pharmaceutical substance identified in the s 70(2) inquiry with the ingredients of the goods on the ARTG and, if the pharmaceutical substance is an ingredient, “[n]o further interrogation of the ARTG is necessary”

Her Honour also noted that the form of the goods registered on the ARTG has no impact on whether s 70(3) is satisfied nor do they require consideration as to whether the goods on the ARTG require formulation, or reconstitution or some other step to be taken for the purposes of administration of the product to a patient.

The Court also interpreted the expression “in substance fall within the scope of the claim” in s 70(2)(a). Her Honour agreed with Sun Pharma’s position that this requires that the pharmaceutical substance per se must take all the essential integers of a PTE claim. For this reason, her Honour found that Sun Pharma succeeded in its attack that the pharmaceutical substances per se do not fall within the scope of the claims because they do not take all of the integers of any of the PTE Claims.

Validity of PTE Claims

Sun Pharma further argued that the pharmaceutical substance per se do not “in substance fall within the scope of the claim” because the claims are invalid for lack of clarity and definition,as required by ss 40(2)(b) and 40(3) of the Patents Act. Specifically, Sun Pharma contended that a person skilled in the art would not be able to determine whether all embodiments of the aripiprazole formulations possess the feature “which upon injection releases aripiprazole over [a specified period of time]”.

The Court first determined whether the claims are limited by result, in this case, a specified drug release period. Notably, the claims described a specific particle size range and excipients but omitted key formulation parameters—such as dosage,injection volume, and site—that experts agreed would impact the drug’s release profile.

Otsuka argued that the release period is an inherent feature of the particle size alone. The Court disagreed, noting that the identical particle size ranges were claimed across formulations with different release durations - at least one weeks or two weeks. This suggested that particle size alone could not account for the claimed release period. Instead, other variables needed to be adjusted to achieve the desired result, supporting that the claims are limited by result.

The Court then assessed whether the claims satisfy s 40(3) and/or s 40(2)(b). In particular, whether a person skilled in the art would be able to adjust the formulations disclosed and claimed in the patent to ensure that they satisfy the release period.

The Court found that the patent does not show the person skilled in the art how to determine whether or not a formulation meets the claimed release duration. Notably, the patent relied on blood plasma concentration data, which the Court held does not equate to "release"from the injection site. Since the patent is silent as to how drug release can be extrapolated from blood plasma concentration, the person skilled in the art (PSA) is not able to use the blood plasma information to enable them to determine whether a formulation which would otherwise fall within any of the claims also satisfy the release period. Furthermore, the Court found that even if the person skilled in the art was able to use blood plasma concentrations as an indirect means, the PSA would be required to engage in burdensome, non-routine experimentation to determine whether any given formulation satisfies the release period.

If you have any questions about pharmaceutical patents or extension of term applications in Australia then please contact Daniel McKinley or Catrina Olivera.

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