So how much experimental information do you need in a patent application?


The ‘Raising the Bar’ amendments to the Australian Patents Act 1990 imported ‘sufficiency of disclosure’ and ‘support’ standards from UK and European law.  However, in practice, with little guidance as yet from the Australian judiciary, these standards are, it seems, being applied inconsistently by Australian examiners.  A recent decision of the UK Supreme Court which addresses the British ‘sufficiency of disclosure’ standard, and particularly ‘plausibility’, has the potential to make the waters even muddier in Australia.


A patent for an invention provides its owner with the right to exclude others from making, using, offering for sale, or otherwise selling the invention.  In exchange for that right, the patent specification must disclose sufficient detail that enables others to make and use the invention.  ‘Sufficiency of disclosure’ and ‘support for a claimed invention’ are but two of several threshold tests that must be met in order to achieve a granted patent.  But how much ‘disclosure’ and ‘support’ is enough?

An insufficient disclosure and/or a lack of support are typically fatal to achieving grant.  However, it is perhaps trite to say that one should simply disclose as much information about an invention as is possible during the drafting process.  Notwithstanding that the interpretation of a patent specifications for compliance with the ‘sufficiency of disclosure’ and ‘support’ requirements is through the eyes of a person skilled in the art (i.e. a hypothetical person who is presumed to be familiar with all of the ordinary technical knowledge in the technical field to which the invention belongs), meeting these requirements isn’t always straightforward.  This is particularly the case in a competitive landscape where there is a race to be the first to patent an invention.  Further, for a complex disclosure directed to, for example, a new class of compound or biologic (e.g. antibody or enzyme), providing exemplary data on all possible compounds/molecules that fall within the class may be impossible and impractical.  To this extent, the law has evolved such that the ‘sufficiency of disclosure’ and ‘support’ requirements are met provided that a prediction that an invention will work broadly across the class is ‘plausible’.

Pfizer feels the pain

We have previously reported on litigation involving Warner-Lambert Company LLC (a subsidiary of Pfizer, Inc)  and  its Australian patent for pregabalin – a pharmaceutical for treating pain.  This previous report covered a decision of the England and Wales High Court concerning European Patent, EP(UK) No 0934061.  A decision issued recently by the UK Supreme Court is an appeal from that earlier High Court decision.

While pregabalin was initially prescribed to treat seizure disorders, it was subsequently found to be a suitable treatment of neuropathic pain.  Patent No. 0934061 is directed to the use of pregabalin in treating pain, otherwise known as a second medical use (i.e. new use of a known compound).  As it turns out, neuropathic pain is different from other types of pain – neuropathic pain is pathological (i.e. caused by a primary lesion or dysfunction of the nervous system).  The patent specification provides examples of inflammatory pain which is nociceptive (i.e. resulting from injury), but not peripheral neuropathic pain (i.e. caused by a primary lesion or dysfunction of the peripheral nervous system) nor central neuropathic pain (i.e. caused by a primary lesion or dysfunction of the central nervous system).

It is known that pregabalin works for the treatment of both peripheral and central neuropathic pain because data from clinical trials (obtained after the priority date) provide unequivocal proof.  However, the question is not whether the drug works, but whether the expectation that it would work has been sufficiently disclosed in the patent specification.

In prior proceedings, Patent No. 0934061 was held invalid on the ground of insufficiency as the description was found to not provide a disclosure that enabled one to treat all types of pain, let alone all types of neuropathic pain.  That is, the specification does not make it plausible that pregabalin would be effective to treat all kinds of pain.

The ‘plausibility’ standard

The UK Supreme Court appeal decision upheld the previous findings on invalidity on the ground of ‘insufficiency’, and particularly a ‘lack of plausibility’.  The decision nevertheless confirms that the plausibility standard under UK patent law is low.  The Court notes (at paragraph 23) that:

  • the concept of plausibility originates in the case law of the EPO as a response to overly-broad claims, and
  • the patent specification should disclose not just what the invention is and how to replicate it, but some reason for expecting that it will work (i.e. ‘plausibility’).

The Court goes further to address the question of whether experimental data is essential to ‘sufficiency’ under UK and European law (see paragraphs 24-37).  In short, the answer is no.  A patent specification need not definitively prove that an invention works for a designated purpose.  However, there is a resounding ‘BUT’ insofar as merely asserting that it is ‘plausible’ that an invention will work for a designated purpose is not enough to meet the ‘sufficiency of disclosure’ standard (see paragraph 37).  Additionally, the Court confirmed that providing post-filing data can be helpful in a dispute about ‘sufficiency’ and ‘plausibility’, but that the data itself cannot be used to rectify an insufficient disclosure.  That is, ‘sufficiency of disclosure’ and ‘plausibility’ must be satisfied at the date of filing.

The fact of the matter is that the specification of Patent No. 0934061 is predictive of efficacy for the treatment of inflammatory pain, but the specification does not make it plausible that pregabalin is effective for the treatment of any kind of neuropathic pain. To this point, the Court concludes that the specification merely provides encouragement to conduct further testing to determine whether pregabalin is effective for the treatment of neuropathic pain, thus confirming the absence of a sufficient disclosure (see paragraph 53).

Advance Australia (Un)fair?

Section 40 of the Australian Patents Act 1990 (post the ‘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, and
  • the claims be supported by matter disclosed in the specification.

Both ‘sufficiency of disclosure’ and ‘support’ require that a disclosure be enabling.

The Explanatory Memorandum of the Intellectual Property Laws Amendment (‘Raising the Bar’) Bill 2011 makes it clear that the requirements of ‘sufficiency of disclosure’ and ‘support’ have been imported from European and UK law in an effort to raise the patentability standard in Australia to the standard as it exists in those jurisdictions.  In practice, our experience is that Australian examiners apply these standards inconsistently (which is perhaps not surprising given the convoluted summary [.doc; 89.0KB] provided as a guide to examiners).  Moreover, it has been the writer’s experience as well that of colleagues that Australian examiners will maintain ‘sufficiency of disclosure’ and ‘support’ objections even where a corresponding European case has been allowed.

To date, there has been no judicial consideration of the ‘sufficiency of disclosure’ and ‘support’ standards under the current Act.  The Australian Patent Office decision in Evolva SA [2017] (‘Evolva’) APO 57 (covered in detail by Dr Mark Summerfield in his Patentology blog), provides some insight to the application of ‘plausibility’ standard in Australia.  To summarise:

  • Determination of enablement requires an assessment of whether (i) a patent specification plausibly establishes that an invention can be worked across the full scope of the claim, and (ii) an invention can be performed across the full scope of the claims without undue burden (see Evolva paragraph 45).
  • The threshold for ‘plausibility’ is low (see Evolva at paragraph 59).
  • ‘Plausibility’ and ‘undue burden’ are not to be determined in isolation, but with reference to the person skilled in the art:
    • The scope of the monopoly, as defined in the claims, must correspond to the technical contribution the patentee has made to the art.  If the assertions made in the specification are not plausible, then it cannot be reasonably said that the patentee has made a contribution to the art (Evolva at paragraph 43).  However, an invention that is plausible may still fail on sufficiency if the specification essentially sets out a research programme and there is an undue burden of experimentation required to put it into practice (see Evolva at paragraph 44).
    • An ‘undue burden’ in this context requires consideration of the nature of the skilled person and the relevant field of technology.  That is, if it is necessary that the person skilled in the art perform additional experiments to put an invention into practice, which apply routine and well-known techniques but which do not require inventive ingenuity, such experiments would not amount to prolonged research or experimentation that would be considered an undue effort in that given field (see Evolva at paragraph 68).

Thus, the Australian Evolva decision is consistent with that  the UK Supreme Court decision re Pregabalin.


While understanding of ‘sufficiency of disclosure’ and ‘support’ patentability standards is still evolving under Australian law, it is perhaps the case that we may never achieve absolute clarity.  These standards require an understanding of the person skilled in the art, and the technical knowledge that such a person possesses.  Without a doubt, the standard of the person skilled in the art changes depending on the subject matter of a patent specification.  Hence, what might be considered ‘sufficient’, ‘plausible’ and/or an ‘undue burden’ in one case will likely vary to the next.  We might therefore expect that Australian examiners will continue to apply the ‘sufficiency of disclosure’ and ‘support’ patentability standards inconsistently in the absence of an understanding of a person skilled in the art. In fact utilising ancillary information provided by such a skilled person when a ‘sufficiency of disclosure’ and/or ‘support’ objection becomes a problem is one avenue that might assist examination.

Many of Watermark’s Biosciences and Chemical Technologies attorneys have years of post doctoral and industrial experience in their technical fields and can assist clients navigate the increasing challenges that ‘sufficiency of disclosure’ and ‘support’ objections are throwing up in Australia.