During the drafting stage of a patent specification, the question often arises as to how much information should be included in the detailed description for enablement purposes. Of course, it is important to include substantial information relating to each of the "essential features" of the invention, which are those feature that either support the claims or provide a clear enough and complete enough description of the invention and (for Australian law purposes) the best method then-known of performing it - especially those features that give rise to the advantages of the invention over and above the prior art. However, often it is not feasible or practical to add a highly detailed description of each and every feature mentioned in the patent specification, as Applicants would need to reproduce large amounts of published text to show the variants known in the prior art, causing patent specifications to run to hundreds of pages in length. This is a particular issue for inventions in the chemical and life sciences fields, where precise descriptions can involve extremely voluminous detail of chemical and structural features, and the permutations or specific variations can number in the thousands or millions (or more).

To circumvent (or at least mitigate) this issue, patent attorneys often adopt a shorthand, which is to "incorporate [published prior art documents] by reference". The Australian Patent Examiner's Manual notes that "cross-references to other documents merely to provide background information or prior art, or to illustrate subsidiary features, are not objectionable provided that . the cross-referenced document . was publicly available on or before the filing date of the specification referring to it".1

The generally accepted practice is for attorneys also to explicitly incorporate by reference material from the priority patent application(s) and the parent patent to the child, grandchild, great grandchild, etc, in case there is any subject matter that has been inadvertently omitted along the way, but becomes important later in prosecution.

The objective (for enablement, sufficiency and support purposes) is to provide a description of how to put the invention into practice over the full scope of the claims without an undue burden of trial and experiment, or the need for further invention. The amount of information to include for enablement, sufficiency and support purposes also interacts with the level of background knowledge and aptitude of the relevant person skilled in the art (skilled addressee), which varies from one field to another. We have recently written on this topic here.

The Australian Examiner's Manual notes that the rules of construction for prior art citations are the same as those that apply to the construction of patent specifications.2 The principles relevant to construction of patents, in particular, incorporation by reference of other documents, focus on the purpose of the incorporation.3 In Nicaro Holdings Pty Limited v Martin Engineering Co (1990) 16 IPR 545,the following was said at 517:

"It is, however, permissible to refer not only to the patent relied on as the source of disclosure but to another patent or other patents incorporated by reference provided that it is plain that the incorporation by reference unequivocally and plainly demonstrates that the draftsman has adopted the cross-referencing system solely as a shorthand means of incorporating a writing disclosing the invention"4 (emphasis added)

In other words, it is permissible to incorporate by reference another patent (or other patents) into a prior art patent (or into the patent specification) where the cross-referencing system has been adopted. However, the mere fact that one document is referred to in a second document does not automatically justify a claim that the second document is intended by its author to be read with the first document so as to form one consistent whole.

In all cases, the context and purpose of incorporating a document by reference (and of any further cross-referencing) is crucial to the nature and extent of information that is in fact brought across from the referenced document to the patent specification under consideration. This can include factors such as whether the document incorporated by reference teaches away from the claimed invention, or whether the incorporated document is in the same (or a related) field. The requirement appears to be that the author of the second document must have incorporated the contents of the earlier document into the later document in order to form one single source of information. An important factor is also how the skilled addressee would regard the document incorporated by reference into the patent.

In Merck Sharp & Dohme Corporation v Wyeth LLC (No 3) (2020) 155 IPR 1, Wyeth submitted (at 891) that prior art document "Jones 2005" was not to be understood as being incorporated by reference in the specification in its entirety, but for the limited purpose identified in the specification; namely, to identify a reference where it had been suggested in the art that silicone oil might be responsible for the aggregation/precipitation seen in protein pharmaceutical preparations. Justice Burley disagreed that the available use of Jones 2005 was so limited on the basis that the specification stated that all patents and publications cited were incorporated by reference, and instead considered that the description of Jones 2005 represented "an invitation to the person skilled in the art to consider Jones 2005 generally for the purpose of understanding the problems caused by silicone oil".

In Idenix Pharmaceuticals LLC v Gilead Sciences Pty Ltd (2017) 134 IPR 1 at 165, a prior art document (the "Emory patent") was not considered to be incorporated by reference in its entirety into the Idenix patent, as the Idenix patent merely had a simple and short reference that it "discloses the use of certain 2'-fluoronucleosides to treat HCV". Nothing further was said about any method of synthesis of the compounds of interest, and the incorporated by reference appears in a section headed "Additional Methods to Treat Flaviviridae Infections", and was referred to as part of a class of drugs developed to treat such infections, that class being referred to as "nucleoside analogs" developed for such treatment. In view of these factors, it was decided that the Emory patent was not being cited for the purpose of incorporating by reference or disclosing a method of synthesis of a compound of interest, but rather its disclosure is made as an example of a compound being used as part of a method of treatment. Accordingly, the attempt by Idenix to "finesse" the disclosure in the Idenix patent by reference to the Emory patent was rejected.

In Apotex Pty Ltd v Warner-Lambert Company LLC (No 2) (2016) 122 IPR 17, a couple of prior art documents were "incorporated by reference", and Justice Nicholas was satisfied that they would be read and understood by the skilled addressee as relevant background material and that the information contained in them would enable the skilled addressee to manufacture the relevant compound without undue difficulty (at 111).

For completeness, at 538-539 in Nicaro Holdings the following observations were made:

"Again, even where there is a further description of the prior publication, it may nevertheless be that the purpose of the reference is to direct the reader away from it, as disclosing something outmoded or defective."

Issues in patent prosecution

Various issues can arise from the practice of "incorporation by reference" during patent prosecution. In particular, an Examiner will often object during prosecution when a document is explicitly incorporated by reference to avoid disclosing matter which is required in order to perform the invention in any of the forms that are claimed. In this case, an amendment is often required to insert the relevant cross-referenced material before the application could be accepted.

Also, in the event that there is doubt as to the content of a referenced document, for example in the case of non-patent documents or if the cross-referenced document is not in English, evidence may be required to establish its disclosure at the filing date of the complete specification before a proposed amendment to explicitly incorporate the matter can be allowed.

As there is little doubt as to the content a published peer-reviewed journal article, or a published book, these kinds of documents would not tend to attract objections by an Examiner. However, the content of a website may be problematic, as its content can be subject to amendment over time, in which case it would be preferable to simply include the information into the patent specification rather than relying on a cross-reference. In any event, it is important to be clear what is being incorporated, either wholly or in part (in which case, which parts), and the specifics of the publication particulars (i.e., book edition, volume, pages, publication date, etc).

Manner of Manufacture

From a validity perspective, the effect of prior art documents incorporated by reference can be a relevant consideration for the ground of manner of manufacture. As set out in NV Philips Gloeilampenfabrieken v Mirabella International Pty Ltd (1995) 183 CLR 655 (at 663-664) the manner of manufacture requirement will not be met if, on the face of the specification, the claimed subject matter is not new or lacks the necessary quality of inventiveness. Accordingly, prior art documents incorporated by reference are included in an assessment of manner of manufacture.

In the seminal High Court of Australia decision in Commissioner of Patents v Microcell Limited (1959) 102 CLR 232, the Court established that there can be no invention in "the new use of an old substance". In Microcell, the question was whether a self-propelled-rocket projector comprising a tube of synthetic resinous plastic material reinforced with mineral fibres was a patentable invention. With respect to that alleged invention, the High Court said (at 251):

"We have in truth nothing but a claim for the use of a known material in the manufacture of known articles for the purpose of which its known properties make that material suitable. A claim for nothing more than that cannot be subject matter for a patent and the position cannot be affected either by the fact that nobody thought of doing the thing before, or by the fact that, when somebody did think of doing it, it was found to be a good thing to do".

In Microcell, the High Court (at 248) gave the example of stainless steel: "If stainless steel and its properties were known, and many kinds of articles had been made of it, it would not be possible for a man to claim a monopoly for making kitchen sinks of stainless steel merely because he was the first man who ever thought of doing this". Incorporating the contents of other patents or documents by reference introduces more content, and potentially more admissions that could found a Microcell-type manner of manufacture attack.

In University of Wyoming Research Corporation v Ciris Energy, Inc. [2016] APO 3, The University of Wyoming submitted that a passage of the specification provided an admission that the claimed invention lacked the requisite level of inventiveness. In particular, a reference cited in that passage, which is a chapter within an edited textbook, was incorporated by reference into the specification and provided a figure illustrating pathways for the bioconversion of coal to methane. It was determined (at 99) that the cited reference "basically establishes that the process defined in claims 1-4 was known . [and that as] the reference forms part of the specification . the specification itself establishes that the defined process was known". At 100, the Hearing Officer concluded that claims 1-4 define matter that, on the face of the specification, lacks the requisite level of inventiveness, and that the claims are not for a manner of manufacture.

In Intervet International B.V. v E. I. du Pont de Nemours and Company [2017] APO 31, Intervet submitted that there was no invention on the face of the specification as it included the content of prior art document D4, which was "incorporated by reference". In particular, Intervet submitted that D4 disclosed certain compounds (especially "Compound 3") that can be administered to control parasites, including fleas in animals.

The specification stated that the relevant compounds can be prepared as described in D4 (including those listed in Index Table A, which included Compound 3). Specially, the patent specification stated that: "Methods for preparing the compounds listed in Index Table A are disclosed in . [D4]. To the extent necessary to teach the methods of preparing the . [relevant compounds], (and only to the extent that they are not inconsistent with the disclosure herein) this patent publication is herein incorporated by reference." (emphasis added)

The Hearing Officer concluded that, in the context of the claimed invention, D4 was only incorporated by reference for the purposes of providing a means for preparing Compound 3, but the biological tests in D4 were not incorporated by reference. Notwithstanding this conclusion, the Hearing Officer also concluded that D4 did not test the relevant compound for in vitro activity against fleas, and concluded that the specification on its face does not disclose the claimed method for protecting a mammal against fleas. The manner of manufacture attack therefore failed.

Amendments to patent specifications

An interesting recent decision is 1414 Degrees Limited v Climate Change Technologies Pty Ltd [2022] APO 38, which considered the allowability of an amendment filed during an opposition proceeding (under s102(1) of the Patents Act) to remedy an inconsistency, and whether the amendment resulted in new matter being claimed or disclosed. In this case, the amendment was deletion of the sentence, "The entire contents of this disclosure are incorporated by reference herein."

The patent specification in question related to a thermal energy storage apparatus comprising a "contiguous block of compressed sintered graphite" heat-absorbing material having at least one receptacle. A "phase change material" is stored in the (or each) receptacle, a preferred form of which is a silicon metalloid which is characterised by the property that, on undergoing a phase change from liquid to solid, there is an expansion of the material rather than contraction as would be expected for most other materials. As the phase change material cools and expands it is "urged upwardly" to disperse pressure and reduce the amount of pressure applied to the block, thereby reducing cracking or fissuring of the block over thermal cycling.

As identified in the background section of the specification, a disadvantage associated with the use of phase change material is absorption of silicon in its liquid form by graphite. However, the specification describes that sintered graphite may be "compressed" which causes it to be densified, and that compressed sintered graphite provides many advantages, such as the liquid silicon not being absorbed by the compressed graphite, which allows "containment tubes" to be omitted.

The Background section of the specification incorporated by reference WO 2013/020176 (WO'176), which itself incorporated by reference WO 2011/017767 (WO'767). WO'767 provided a thermal energy storage apparatus comprising a series of canisters used to store silicon metalloid, and which are packed in interleaved arrangement with a series of sintered graphite rods, but that "in such arrangement the canisters are prone to cracking, particularly in the region of the grooves".

As the Hearing Officer noted (at 22) that "This matter is somewhat unusual. The amendment comprises deletion of a sentence from the part of the description labelled 'Background of the Invention'", i.e.:

"This problem with . [WO'767] is addressed in . [WO'176], also to the present applicant. The entire contents of this disclosure are incorporated by reference herein. In this regard, it was recognised that by providing a block of heat-absorbing material in the form of a contiguous block of compressed material in the form of sintered graphite which is machinable, greater heat transfer from the block to the heat storage elements can be achieved. Although the performance of the thermal energy storage apparatus is greatly increased, containment tubes are still used, thereby reducing the efficiency of the apparatus, and cracking of the heat absorbing material can still be a problem. It is desirable to remove the containment tubes, though this leaves the block prone to cracking."

Turning to the disclosure of WO'767, the background section of that patent included the following information:

"The expansion and contraction of the silicon metalloid material creates significant build-up of pressure on the enclosure or confinement in which it is placed inside the energy storage apparatus.

In one embodiment described in the document, it is taught that the silicon metalloid material would be ingots, which would be introduced into a series of longitudinal cavities that have been shaped into the pressurised moulded block of sintered graphite.

As the person skilled in the art would know such an arrangement would result in the metalloid being absorbed by the graphite when the phase change occurred." (emphasis added)

Accordingly, the effect of the amendment was to exclude incorporation in the opposed application of the disclosure in WO'767 that the skilled addressee would know that metalloid introduced as ingots into longitudinal cavities in a densified block of sintered graphite would be absorbed by the graphite when a phase change occurred, thereby rectifying inconsistency of statements in the body of the specification.

The Opponent argued that removing the inconsistency regarding the performance characteristics of compressed sintered graphite by way of the proposed amendment resulted in the complete specification disclosing matter extending beyond the complete specification as filed. As per the Opponent's submissions:

".this new version of the specification resulting from the proposed amendment, where there is no contradiction or inconsistency, and where in effect a selection has been made for one set of characteristics of compressed sintered graphite, vis-à-vis its capability to contain liquid silicon, over another, is plainly not matter that is clearly and unambiguously disclosed in the complete specification as filed or to put it another way is clearly not matter which the hypothetical skilled person could directly derive by reading the information in the specification as filed ."

The Applicant argued that deletion of reference to WO'176 (and therefore WO'767), and the statement within it inconsistent with the teaching of the application did not result in a claim to, or disclosure of, "matter that extends beyond that disclosed" in the application as filed, and that the relevant question when considering if the amended specification extended beyond the complete specification as filed was whether the skilled addressee would learn anything about the invention they could not learn from the unamended specification. The Applicant argued this was not the case, and the Hearing Officer agreed, although did note that deletion of subject matter can (in some cases) have the effect of adding matter.

It is worth noting here the confirmation by the Full Federal Court in AstraZeneca AB v Apotex Pty Ltd (2014) 107 IPR 177 that inventive step is not measured using the information disclosed in the patent specification as the "starting point" - rather, inventive step must always be assessed in comparison to the common general knowledge (CGK), established through evidence, either alone or together with s7(3) information. Therefore, while incorporation by reference can create issues under the ground of manner of manufacture (which is concerned with what is disclosed on the face of the specification), it should not directly create issues for inventive step - although in practice it could affect what constitutes the CGK, as a forensic issue of proof.

Expanding the footprint of a patent specification as future prior art

Incorporation of prior art documents by reference can also have the unintended consequence of broadening the disclosure of a patent specification as future prior art. This is one of the more likely ways to combine documents under s7(1) for novelty and s7(3) for inventive step - assuming that the cross-referenced documents are not themselves already considered "a single source of that information" (under s7(1)(b)), or where "the skilled person could be reasonably expected to have combined" the documents (under s7(3)(b)).

It may be the case that a second document would not rise to the level of being considered a single source of information with a patent specification (or that document and patent specification be reasonably expected to be combined), but the incorporation by reference tips the scales such that the second document and patent specification are considered one consistent whole. This can be a good way to prevent future competitor patenting in the space. However, this may also create enablement difficulties for the patentee's own patent application if not careful.

Key takeaways

  1. Cross-references to other documents merely to provide background information or prior art, or to illustrate subsidiary features, are not objectionable provided that the document was publicly available on or before the filing date of the complete specification.
  2. When a document is explicitly incorporated by reference to avoid disclosing matter which is required in order to perform the invention in any of the forms that are claimed, an amendment is required to insert the relevant cross-referenced material before the application can be accepted.
  3. In the event that there is doubt as to the content of a referenced document, evidence may be required to establish its disclosure at the filing date of the complete specification before an amendment to incorporate the matter can be allowed.
  4. It is preferable to include the actual text/drawings from the referenced document that is essential to understanding or performing the invention, rather than relying on incorporation by reference.
  5. If a document incorporated by reference is essential to understanding or performing an invention, ensure that it is referred to and described in the priority application.
  6. Applicants should ensure that the disclosure in any divisional application includes the disclosure of any parent or ancestor applications by using an explicit incorporation by reference.


1 Patent Office Examiner's Manual at "Inclusion of References".

2 Patent Office Examiner's Manual at "Construe As For Any Other Document".

3 Apotex Pty Ltd v Sanofi-Aventis (2008) 78 IPR 485 at [121]; ICI Chemicals at [88]-[90], and Nicaro Holdings Pty Ltd v Martin Engineering Co (1990) 91 ALR 513 at 517 and 532-539.

4 George C Warner Laboratories Pty Ltd v Chemspray Pty Ltd (1967) 37 AOJP 2513 at 2516; Blanco White, 5th ed, at para 4.107 and Gratwick, "Having Regard to What was Known and Used" (1972) 88 LQR 341 at 343.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.