Legal Insights

It's about time the Australian Patent Office required more precision

By Ben Miller & Jenny Wong

• 24 May 2022 • 12 min read
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We discuss the difficulties that can arise from the use of terms of approximation (e.g. “about”) in patent claims.

In brief

Unlike the United States, courts generally do not conduct early separate claim construction hearings in patent cases in Australia. This means that the construction of imprecise claim terms, which are often allowed during examination in Australia, is not resolved until a final hearing in litigation, or even upon appeal.

In Pharmacia LLC v Juno Pharmaceuticals Pty Ltd [2022] FCA 92 the Federal Court held at first instance that three out of six representative batches of Juno’s generic parecoxib products fell within the claims of Pharmacia’s patent. Although the case was fully litigated over three years and a two-week trial, including a cross-claim for revocation of the patent, the infringement questions turned almost entirely on matters of claim construction, particularly as to certain imprecise terms, such as “about”. This litigation exemplifies the barriers to entry created by the Australian Patent Office’s practice of allowing imprecision in ranges of values in claims, particularly in allowing words of approximation that have no established technical meaning in the relevant art.

Background

Pharmacia LLC is the patentee of Australian Patent Number 2002256031 (the Patent), which relates to the formulation and administration of selective cyclooxygenase-2 (COX-2) inhibitors. Pharmacia is the manufacturer of parecoxib, which is marketed in Australia as DYNASTAT. Pfizer Australia Pty Ltd, a related entity, is the exclusive licensee in Australia of the Patent.

In April 2018, Juno Pharmaceuticals Pty Ltd obtained registration on the Australian Register of Therapeutic Goods (ARTG) for formulations of parecoxib (as sodium) (the Juno Products). Juno markets and supplies the Juno Products in Australia. Before August 2020, Neo Health (Australia) Pty Ltd supplied the Juno Products to Juno for sale in Australia.

Pharmacia and Pfizer Australia brought proceedings against Juno and Neo Health for infringement of the Patent. Juno denied infringement of the Patent and cross-claimed seeking revocation of the asserted claims in respect of the grounds of lack of inventive step, lack of clarity and lack of definition.

Infringement

In the course of the proceedings, Juno provided documents to Pharmacia concerning the composition and manufacture of six batches of Juno Products, none of which were imported into Australia. The trial proceeded on the basis that resolution of the disputed issues of construction and infringement for these batches would be sufficient for the result to be applied to batches of the Juno Products that had been imported and sold in Australia.

As the claims of the Patent required certain percentage ranges of active ingredient and excipients, a number of issues arose for construction.

Therapeutic agent in the Juno Products

Justice Burley found that the specification and claims distinguished between parecoxib per se and parecoxib in the form of a salt and that both were identified as distinct “therapeutic agents”. His Honour held that the expression “at least one water-soluble therapeutic agent” in the context of claims 1 and 26 referred to either a drug, a prodrug or a salt thereof, depending on which is actually added to the formulation. His Honour concluded, therefore, that if a composition is formulated using parecoxib sodium as the selective COX-2 inhibitory salt of the prodrug parecoxib, then parecoxib sodium is the “water soluble therapeutic agent”.

Meaning of “about”

Claim 1 required an amount of therapeutic agent “constituting about 30% to about 90% by weight”. Pharmacia argued that the word “about” signified a margin of error of 5%, so would include, for example, a composition with 94.5% therapeutic agent. Juno argued that “about” allows for rounding to the nearest whole number, such that “about 90%” extends to 90.49% as its upper limit.

While the Court found the question “by no means easy to answer”, his Honour considered that the specification and evidence support a narrow construction of the term “about” that permits a small amount of variance from the ranges specified in claims 1 and 26 (and their dependent claims), but confined to the rounding to the nearest whole percentage point. The court agreed with Juno that “about 90%” in claim 1 extends to 90.49% as its upper limit, especially given the evidence of the typical use of precise measurements in pharmaceutical sciences, and the examples in the patent itself descending to measurements to two decimal places.

Importantly, in a reminder that the language of the claims of a patent are in words of the patentee’s own choosing, his Honour said:

“The inventors have gone to the trouble to specify the scope of their monopoly by reference to the range between these specific figures. As a matter of construction, the word “about” should not be understood to supply any significant extension of the ranges nominated.
Residual water

Pharmacia argued that any residual water in the freeze-dried lyophilised product must be included in the weight of the composition. Juno argued that it should be excluded, as an uncontrolled artefact of the lyophilisation process.

Justice Burley considered that the evidence and specification, including the claims, makes clear that the lyophilisation process, although designed to remove all water from the composition during the freeze-drying process, in practice will likely leave some residual water in the lyophilisate. Accordingly, his Honour held that any residual water in the composition must be taken into account when considering the total weight of the composition of claim 1 (and its dependent claims), but not claim 26 (and its dependent claims), which expressly excluded water.

Meaning of “essentially”

The formulation experts agreed that in the context of claim 11 “essentially” means “mostly” such that the composition of the claim contains mostly, but not exclusively, the therapeutic agent and a buffering agent, although other things (such as water) could also be present. His Honour held that “essentially” in claim 11 did not extend the scope of the monopoly claimed beyond the limits of claim 1.

Total weight of parecoxib sodium

Having construed the claims, the Court turned to certain questions regarding the proper approach to infringement questions.

The parties disputed whether the weight of parecoxib sodium should be determined from the batch formula and product description, or from the results of a high-performance liquid chromatography (HPLC) assay in the certificates of analysis for each batch. Taking into consideration that the purpose of the assay is to verify, to one decimal point of a percentage value, that what goes into a batch is sufficiently accurate to allow the product to be described as having the dose listed, Burley J held in favour of the view of Juno’s expert that it was appropriate to take into account the assay result in measuring the amount of parecoxib sodium in the six batches.

pH adjusters

The parties were also in dispute on how to treat the pH adjusters (acids or bases used to adjust pH in a formulation) in calculating the weight of the composition of claim 1. Taking into consideration the directions in the Product Description and Manufacturing Process Description to add the pH adjusters “q.s.” (or in quantities as required to adjust the pH), and the expert evidence that generally only one of the two pH adjusters would be required in any given batch, Burley J concluded that no weight for pH adjusters should be included in the calculation, because no weight could be arrived at for any given batch, and Pharmacia bore the onus to establish infringement.

Invalidity

Lack of inventive step

Juno argued that the invention claimed in the asserted claims of the Patent would have been obvious to the person skilled in the art in light of two prior art documents (Jain and Talley) and that application of Jain and Talley to an eight step “development pathway” would have led to the claimed invention.

Burley J was satisfied that the hypothetical skilled team would readily navigate each of steps 1, 2 and 3, which involved the identification of Jain by a pain specialist (a member of the notional formulation team), that Jain would then be supplied to a formulation expert who would obtain Talley (footnoted in Jain). His Honour was also satisfied that upon reading Jain and Talley, the hypothetical skilled team would decide to attempt to formulate parecoxib sodium as an intravenous formulation.

However, Burley J was not satisfied that Juno had shown that the skilled team armed only with the common general knowledge and the information in Jain and Talley could have obtained valdecoxib (in order to synthesise parecoxib sodium) before the priority date. Despite this finding, his Honour proceeded to analyse the following steps in the event his analysis of this step was incorrect.

Burley J found that the notional research group would first try a ready-to-use liquid formulation, and then seek to overcome the instability of the resulting liquid formulation. Juno argued that this would be done as a matter of course by preparing a freeze dried (lyophilised) formulation. This gave rise to Pharmacia’s “timing argument”.

Pharmacia argued that the invention could not be obvious in light of Jain and Talley because there was insufficient time between the date of publication of Jain and the priority date of the patent for the necessary stability tests in the development pathway to take place. Essentially the argument was that if the hypothetical team started with Jain and Talley on Jain’s publication date, then the instability of a ready to use formulation would not be identified in the development process until after the priority date, so part of the problem would not have been identified before the priority date.

Burley J rejected this argument, emphasising that the explicitly hypothetical nature of the enquiry, and that a person skilled in the art is a tool of analysis, not an avatar for an expert witness. His Honour also noted the “statutory language does not invite a drift from the hypothetical to the practical in terms of timing”. His Honour regarded Pharmacia’s argument as analogous to one which was rejected by the Full Court in Novozymes A/S v Danisco A/S [2013] FCAFC 6.

Ultimately, however, Burley J was not satisfied that the notional research group would be directly led as a matter of course to a reconstitutable lyophilised powder formulation within the relevant claims. His Honour also had regard to the likelihood that the hypothetical formulator would add a bulking agent which would have taken the formulation outside the claims of the Patent. His Honour therefore held that Juno had failed to establish that the claimed invention was obvious.

Lack of clarity and definition

As an alternative to its primary case, Juno argued that use of the term “about” in the asserted claims was indefinite, unclear and did not provide a workable standard. Juno also argued that the same defects applied to the use of the term “essentially” in claim 11. In light of his construction of “about” and “essentially”, Burley J held that Juno had failed to demonstrate that the asserted claims lacked clarity and definition.

Implications

The sheer number of disputes as to the correct interpretation of the claims, and the requirement for a Court ruling on the limits of the expression “constituting about 30% to about 90% by weight”, brings the examination approach of the Australian Patent Office into focus.

IP Australia’s current Patent Manual of Practice and Procedure states:

“Claims frequently contain terms that are imprecise. This does not give rise to an objection of lack of clarity if it is possible to ascertain whether an act would fall within the scope of the claim. This is a practical determination, rather than a strictly literal exercise, and it is acceptable if there is minor uncertainty at the edges of a claim…”
“Only clarity matters that affect the overall scope of the monopoly should be raised. In general, objections will be restricted to situations where the imprecise terms relate to the inventive concept and the terms would not be understood by the person skilled in the art. Consequently, terms such as "about", "substantially", "approximately", "essentially", "particularly", "preferably", or "for instance" should only be objected to if they cause the ambit of the claim to become uncertain.”

Here, it is difficult to imagine the expression “about 30% to about 90% by weight” giving rise to anything other than uncertainty in the overall scope of the monopoly. The expression “about” was not central to the inventive concept, such as “substantially level” in Leonardis v Sartas [1996] FCA 449. Rather, the expression served to demarcate, within a range of values, the monopoly claimed from the prior art. The form of the claim leaves potential competitors in an invidious position. They may avoid marketing products well outside the 30%-90% range for fear of litigation.

It is about time the Patent Office revisited its approach to clarity objections when it comes to the question of ranges of values in independent claims. In the meantime, however, Burley J’s reminder that the language of the claims are in the words of the patentee’s own choosing provides added certainty that “the word “about” should not be understood to supply any significant extension of the ranges nominated”.

On 26 April 2022, Pharmacia and Pfizer applied for an extension of time and leave to appeal the decision of Burley J to the Full Court of the Federal Court. The application for extension of time and leave to appeal was granted on 10 May 2022, so its likely the Full Court will be asked to weigh in on this issue before the end of the year.

Key lessons

  • Pharmacia v Juno applies the Federal Court’s approach to construing imprecise claim terms, namely, that words used in the claims are to be given the meaning which persons skilled in the art would attach to them, having regard to their own general knowledge and to what is disclosed in the body of the specification.
  • Allowing imprecision in words of approximation which have no established technical meaning in the relevant art, however, can create particular uncertainty and therefore barriers to entry. In the meantime this judgment reminds us that claims which specify ranges of values should not be understood to provide any significant extension of the ranges nominated.

By Ben Miller & Jenny Wong

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