In a recent decision, the Australian Patent Office has provided further guidance as to the patentability standard of ‘sufficiency of disclosure’, and particularly the issues of ‘plausibility’ and ‘undue burden’.

How much ‘disclosure’ is enough?

We have previously written on the standard of ‘sufficiency of disclosure’ from the perspective of ‘asking how much experimental data is required to be disclosed in a patent specification?’. The main points are as follows:

  • Section 40 of the Australian Patents Act 1990 (post the 2013 ‘Raising the Bar’ amendments) requires that a patent specification disclose the invention in a clear enough and complete enough manner (i.e. ‘sufficiency of disclosure’) such that the invention can be performed without undue burden or need for further invention.
  • To date, there has been no judicial consideration of the ‘sufficiency of disclosure’ standard under the current Act.
  • A prior Patent Office decision (Evolva SA [2017] (‘Evolva’) APO 57) provided a three-step test for determining ‘sufficiency’ in view of guidance from the UK and Europe, namely:
  1. What is the scope of the invention as claimed?
  2. What does the specification disclose to the skilled person?
  3. Does the specification provide an enabling disclosure of all the things that fall within the scope of the claims, and in particular:

(a) Is it plausible that the invention can be worked across the full scope of the claim?

(b) Can the invention be performed across the full scope of the claim without undue burden?

  • ‘Plausibility’ and ‘undue burden’ are not to be determined in isolation, but with reference to the person skilled in the art and the technical knowledge that they possess.
  • Thus, while a patent specification need not disclose exhaustive amounts of data to be enabling, what might be considered ‘sufficient’, ‘plausible’ and/or an ‘undue burden’ will depend on the nature of the person skilled in the art and their technical knowledge.

Extending the life of biotherapeutics

The decision by the Patent Office in Gary B Cox v MacroGenics, Inc. (‘MacroGenics’) [2019] APO 13 relates to the opposition to Australian patent application no. 2012259162 (‘the 162 Application). The invention in the 162 Application is directed to extending the life-span of protein-based biotherapeutics.

Biologicals or biotherapeutic products are engineered using biotechnology, and have a wide variety of therapeutic applications. Good examples are recombinant insulin, human growth hormone and erythropoietin which have been known for decades. The problem with some biotherapeutics is that they can disappear quickly after entering the body, particularly as a result of degradation and/or clearance. This poses a problem when it comes to maximising therapeutic efficacy.

For protein-based biotherapeutics administered through the blood stream, numerous strategies for extending life-span have been developed. One particular strategy is disclosed in the 162 Application. The invention in the 162 Application concerns coupling a protein-based biotherapeutic with a part of a protein derived from Streptococcal bacteria that binds serum albumin, which is the most abundant protein in human blood. The idea is that, following introduction into the blood stream, the coupled biotherapeutic-Streptococcal protein binds serum albumin increasing its size. This increased size helps prevent the biotherapeutic from being filtered out of the blood by the kidney, and may also slow degradation.

The 162 Application goes a step further. What also impacts clearance from the blood is that the coupled biotherapeutic-Streptococcal protein can trigger the body’s immune system. To this point, the 162 Application also explores variation (by mutation) of the Streptococcal protein portion such that it is reduced in its capacity to trigger an immune response (which is referred to in the application as ‘deimmunization’) without impacting its ability to bind serum albumin.

“Plausibility’ standard is low, but ‘undue burden’ still a hurdle

To better understand the Delegate of the Commissioner’s analysis of ‘sufficiency’ in MacroGenics, it is necessary to consider the key elements of the broadest independent claims of the 162 Application (an approach taken by the Delegate) according to the following diagram:

  • ‘PT’ is the protein-based therapeutic. According to the broadest claims, PT could be any protein-based biotherapeutic.
  • ‘SP’ is described as a portion of a variant of a wild-type Streptococcal protein that binds serum albumin, where the variant has an amino acid sequence comprising one of two specific forms of deimmunizing mutations.
  • The claims provide the qualification that the deimmunized SP binds albumin and extends the PT’s life-span compared to PT lacking SP.

The analysis of sufficiency begins at paragraph 56 and follows the three step test mentioned above. Drawing on a recent UK decision (which we discussed in our previous article), the Delegate concluded at 61-63 that ‘plausibility’ is a low threshold, but a threshold nonetheless. It requires consideration of whether the specification, as originally filed and understood by the skilled person, provides ‘a reasonably credible technical or scientific basis that an invention can be worked across the full scope of a claim’. At 66-69, the Delegate confirmed that ‘consideration of what constitutes an undue burden is necessarily dependent upon the nature of the technology, and factors relevant to the consideration include the level of predictability in the art and the level of guidance in the specification’. That is, there is a distinction between a disclosure which enables the person skilled in the art to perform the invention compared to a disclosure requiring further significant research to perform the invention.

In view of the nature of the person skilled in the art, common general knowledge and contemporaneous documents, the Delegate found it plausible, and not an undue burden, that PT could be any protein therapeutic even though the specification disclosed particular PT forms (see paragraph 83). To this point, the Delegate determined that the inventive concept really concerned the deimmunized SP-portion of the therapeutic, and not the PT to which SP might be coupled.

What the Delegate did have issue with was the use of the word ‘comprising’. The Delegate acknowledged (at paragraph 50) that the word ‘comprising’ can be interpreted under Australian law to be inclusive or exclusive of further components depending on the context of its use. In the claims at issue, the Delegate found that ‘comprising’ was being used inclusively. That is, while the variant of SP is defined as ‘comprising’ one of two specific forms of deimmunizing mutations, the use of ‘comprising’ meant that the variant could include other mutations which were not specifically defined, albeit that the language of the claims required that any additional mutations not impact deimmunization, serum albumin binding or the extension of life span.

At paragraph 101, the Delegate concluded that it would be plausible to identify variants that satisfy the functional requirements of the claim. However, given that the number of possible variants was large, identification of variants with the desired properties, while routine, would be unpredictable (paragraph 107). In other words, the specification did not provide sufficient enablement for all possible variants of SP according to the claims. Accordingly, the Delegate concluded that there would be an undue burden to work the invention across the scope of the claims, and thus that the specification was insufficient. Based on this ‘lack of enablement’, the Delegate also concluded that the claims lack support under s 40(3).

Are we starting to see consistency with examination of ‘sufficiency of disclosure’ in Australia?

Although we are seeing the test for determining ‘sufficiency’ provided in Evolva more commonly used by Australian examiners, the many factors that feed into test will likely result in continued inconsistency in examination of ‘sufficiency’. This decision, nevertheless, provides confirmation that the standard for ‘plausibility’ is low in Australia, which should provide some guidance to those dealing with s 40 hurdles. Additionally, it should be noted that MacroGenics, Inc. has been given two months from the date of the Delegate’s decision to amend the claims of AU 2012259162 to address the findings of ‘insufficiency’ and ‘lack of support’. Noting that a similar opposition has taken place in relation to the European application corresponding to AU 2012259162, MacroGenics, Inc. will likely adopt the amendments to the claims that have been deemed allowable in Europe (that, in part, replace ‘comprising’ with the more narrowly construed word ‘consisting’).