Following changes to United States law brought about by the America Invents Act in 2011, a patent applicant’s failure to comply with the ‘best mode’ requirement no longer provides a ground upon which a United States patent may be revoked. Many other jurisdictions, including Europe, do not impose any such requirement to disclose a ‘best mode’ or ‘best method’. In contrast, the requirement imposed by section 40(2) of Australia’s Patents Act 1990 (Cth) (Patents Act) that a complete patent specification must disclose the best method known to the patent applicant of performing the invention continues to provide a ground upon which a patent application may be refused and a granted patent may be revoked. 

While a best method requirement has long been a feature of Australian patent law, until recently it had been the subject of relatively little judicial consideration. However, recent decisions of the Federal Court of Australia relating to inventions in the life sciences sector have highlighted the potential consequences for patents that fail to meet the best method requirement, and have provided useful guidance as to its application in Australia.

Apotex v Servier

The patent in issue in Apotex v Servier was Australian Patent No. 2003200700 (the ‘700 Patent), for which Les Laboratoires Servier (Servier) was the patentee. The ‘700 Patent was directed to the arginine salt of perindopril, a compound used in the treatment of arterial hypertension and heart failure that is marketed in Australia by Servier Laboratoires (Aust) Pty Ltd (Servier Australia) as Coversyl.

The specification of the ‘700 Patent stated that the arginine salt of perindopril was found to have a greater stability when exposed to heat and humidity as compared to the erbumine salt of perindopril, which had previously been marketed in Australia by Servier Australia under its Coversyl brand.

Apotex Pty Ltd (Apotex), wishing to enter the market with a generic version of perindopril arginine, commenced proceedings against Servier seeking orders for revocation of the ‘700 Patent on various grounds, including that the ‘700 Patent did not satisfy the best method requirement.

Best method decisions

It was established in the course of the first instance proceeding that at the time that Servier filed the application for the ‘700 Patent it was aware of two specific methods for preparing perindopril arginine (the 1986 and 1991 Methods), neither of which had been specifically disclosed in the specification. The specification of the ‘700 Patent provided only a general disclosure that perindopril arginine had “been prepared according to a classical method of salification of organic chemistry.”

Apotex argued that the general disclosure of a “classical method of salification of organic chemistry” did not meet the best method requirement in the circumstances because Servier in fact knew of two specific methods of preparing perindopril arginine that had not been disclosed in the specification. Servier argued that its identification of the compound perindopril arginine was sufficient to satisfy the best method requirement because the claims of the ‘700 Patent related only to the product of the invention, rather than any process for producing it. Servier also pointed to the fact that Apotex had not established with any evidence that one or both of the 1986 or 1991 Methods were in fact better than the general disclosure of a “classical method of salification of organic chemistry” in the specification.

In his first instance decision in the matter1 , Justice Rares sitting as a single judge of the Federal Court of Australia, noted that at the time of filing the application for the ‘700 Patent, Servier had used a particular method or methods of salification that produced a guaranteed result (i.e. The 1986 and 1991 Methods), but the general description of  “a classical method of salification of organic chemistry” in the ‘700 Patent left to chance whether a skilled addressee would choose, from among a very large range of variables that could affect the result, the method or methods that Servier knew worked to enable perindopril arginine to be used in a tablet form. His Honour concluded that Servier had failed to comply with its obligation to disclose the best method known to it of performing the invention.

On appeal, the Full Court of the Federal Court of Australia unanimously upheld Justice Rares’ first instance decision that the ‘700 Patent did not satisfy the best method requirement.2 The Full Court noted that the nature and extent of the disclosure required in order to satisfy the best method requirement will depend on the nature of the invention itself. In the case of the ‘700 Patent, the ‘point of the invention’ related to the storage properties of the claimed compound, which could vary depending on the nature of the salt formed by a particular method of salification. As such, in order to satisfy the best method requirement it was incumbent on Servier to disclose the method or methods of salification that it had in fact successfully used to prepare perindopril arginine.

Amendment decisions

Australia’s Patents Act confers courts with a broad discretion to permit or refuse to allow a patentee to amend a granted patent3 , and a patentee seeking to do so is required to make out its case in favour of exercise of that discretion under an obligation of candour as to the relevant circumstances and reasons for seeking the amendment. 

In its decision in the Apotex v Servier proceedings, the Full Federal Court unanimously upheld Justice Rares’ first instance decision not to exercise the Court’s discretion to allow Servier to amend the ‘700 Patent to remedy the failure to meet the best method requirement by introducing descriptions of the 1986 and 1991 Methods into the body of the specification.4 Central to both Justice Rares first instance decision and the Full Court’s decision on appeal was Servier’s failure during prosecution of the ‘700 Patent to act on its patent attorney’s recommendation that it include a method for manufacturing perindopril arginine in the specification.

As Servier was unable to remedy the failure to meet the best method requirement by introducing amendments to the specification, all claims of the ‘700 Patent were subject to revocation.

Special leave application

In June 2016, the High Court of Australia refused Servier’s application for special leave to appeal the Full Court’s decision5 , extinguishing Servier’s final avenue for appeal.

GSK v Apotex

The patent in issue in GSK v Apotex was Australian Patent No. 2001260212 (the ‘212 Patent) in the name of GlaxoSmithKline Consumer Healthcare Investments (Ireland) (No. 2) Ltd, (GSK). The ‘212 Patent was directed to a sustained release paracetamol bilayer tablet with a specified in vitro dissolution profile, a formulation that is marketed in Australia by GlaxoSmithKline Australia Pty Ltd (GSK Australia) as Panadol Back & Neck Long Lasting and Panadol Osteo.

GSK commenced proceedings against Apotex and Generic Partners Pty Ltd (Generic Partners) (together, the Respondents) for anticipated infringement of the ‘212 Patent on the basis of the Respondents’ intentions to supply bilayer sustained release paracetamol tablets in Australia. The Respondents brought cross-claims against GSK seeking orders revoking certain claims of the ‘212 Patent on a number of grounds, including that the ‘212 Patent did not satisfy the best method requirement.

The Respondents’ best method ground

The Respondents pointed to the fact that the ‘212 Patent failed to disclose the grade and specific viscosity of hydroxypropyl methylcellulose (HPMC) or the method of granulation that was used to produce two sustained release bilayer tablet formulations that were exemplified in the specification (Formulations C and D). The specification of the ‘212 Patent provided only general descriptions that a “high viscosity HPMC” and “conventional” method of granulation were used, but it was not in dispute that the patent applicant had in fact used a particular grade and specific viscosity of HPMC and a particular granulation end point to make Formulations C and D. The Respondents argued that the method that had actually been used to make Formulations C and D was ‘better’ than that disclosed in the specification because it would eliminate experimentation involved in trying a variety of possible high viscosity HPMC grades and granulation end points in order to make formulations which were guaranteed to work.

Justice Beach, sitting as a single judge of the Federal Court of Australia, rejected the Respondent’s argument on the basis that it was premised on an incorrect identification of the ‘invention’ of the ‘212 Patent.6 His Honour considered that the invention of the ‘212 Patent was to “to formulations having a unique IR:SR [immediate release to sustained release] paracetamol ratio, a matrix forming polymer and dissolution profile.”. This ‘invention’ was a formulation with broader specifications than merely Formulations C and D which were themselves the best method known to make or perform the invention known to the patent applicant. Noting that the experts agreed that they could make the exemplified formulations, his Honour considered that the respondents’ attack could be reduced to “little 

more than saying that there had been a failure to disclose the best method of making the best method of performing the invention”7 , a compounded idea that is not the statutory requirement under the Patents Act.

Appeal proceedings

At time of writing, Justice Beach’s decision in GSK v Apotex is the subject of appeal proceedings before the Full Court of the Federal Court of Australia which are due to be heard in early 2017. Among the matters that have been appealed are his Honour’s findings in relation to best method.

Guidance for the life sciences sector

The Servier v Apotex and GSK v Apotex decisions highlight the importance of giving proper consideration to and identifying what the ‘invention’ of a patent is when assessing the nature and level of disclosure required in order to satisfy Australia’s best method requirement. While the decisions in Servier v Apotex provide clear guidance to prospective patentees that aspects of a known method that are material to the advantages it is claimed that the invention brings should be disclosed in the specification, both the decisions in Sevier v Apotex and GSK v Apotex illustrate that whether aspects of a particular method need to be disclosed will depend on an assessment and the correct identification of the invention.

The primary judge and Full Court’s refusal to exercise the Court’s discretion to allow Servier’s proposed amendments to remedy its failure to satisfy the best method requirement serves as a caution to patentees of the potential consequences of not disclosing matter that is an aspect of the best method of performing the invention at the filing date. While there is some inconsistency in the case law in respect of the question of the date by which the best method known to an applicant must be included in a specification, as a result of the changes to the Patents Act brought about by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 (Cth), for patent applications filed after 15 April 2013 or for which a request for examination was made after 15 April 2013 it is no longer possible to amend a complete patent specification to include matter that extends beyond that which was disclosed on application in order to rectify a failure to disclose the best method (or for any other reason, and with very limited exceptions). The practical effect of this change of law is that the best method will need to be considered and included in the specification for such new applications upon filing.

Australia’s best method requirement, and the consequences for failing to meet it, stands in stark contrast with the patent laws of other jurisdictions. In the life sciences sector, where patents rights will often underpin the commercial value of a product or indeed a business, it is of paramount importance that any prospective patentee for an Australian patent carefully consider, and disclose in the specification upon filing, the best method of performing the ‘invention’.