It is a fundamental part of the contract between a patent applicant and the State that to be entitled to the monopoly period conferred by patent protection the applicant must teach the public how to work the invention disclosed in the patent specification. In the mechanical field this may be a short description of the working of the inventive apparatus, while in the biological and chemical fields numerous examples may be required describing the preparation, use and efficacy of the claimed active agent.

Some countries, notably the U.S. and Australia, go one step further and require that the patent specification describe the best method known for working the invention; sometimes referred to as the ‘best mode’ requirement. Many other jurisdictions, including Europe, require only that at least one way of practicing the invention be disclosed without the need for it to be the best known to the applicant. The current situation in the U.S. is that while the best mode is required to be disclosed by the inventor it is no longer available, since the changes brought in by the Leahy-Smith America Invents Act, as a ground on which a granted patent can be revoked.

Australia then can be viewed as something of a high watermark jurisdiction in that 1) a complete patent specification must “disclose the best method known to the applicant of performing the invention” if it is to proceed to grant, and 2) a granted patent can still be challenged, and ultimately revoked, if the best mode requirement is shown in court not to have been fulfilled.

It is important that patent applicants in jurisdictions which do not have a best mode requirement bear this in mind when preparing patent specifications which will be first filed in their home country but will later result in a national patent application in Australia or the U.S.. Failure to include the best method of working the invention known to the applicant at the time of filing could potentially prove fatal to an Australian application. This is more so because while invalidity of a patent on the grounds of novelty and inventive step are considered on a claim by claim basis, failure to disclose the best mode typically infects the entire patent, thereby invalidating all claims in one fell swoop.

Such a scenario forms the background to a recent decision from the Australian Federal Court (Apotex Pty Ltd v Les Laboratoires Servier (No 4) [2015] FCA 104). This case is just one of many around the globe involving Servier and various generic medicines manufacturers and taking in different legal challenges around Servier’s antihypertensive active ingredient – perindopril. This particular challenge was raised against an Australian patent of Servier’s (the Patent) directed to the arginine salt of perindopril (marketed as Coversyl arginine). In an earlier Australian Federal Court challenge (the ‘earlier decision’) (Apotex Pty Ltd v Servier Laboratories (Aust) Pty Ltd [2013] FCA 1426) Apotex had challenged the Patent on grounds including novelty, inventive step and fair basis but succeeded on only a single ground – failure to disclose the best method known to Servier of working the invention.

The Patent did describe a general method of classical salification for the preparation of the arginine salt of perindopril in a manner which would have allowed a person of skill in the art to generate the product.  Thus the ‘sufficiency’ requirement, under the former Patents Act 1990 (which is the relevant law applying to the Patent), was satisfied, because the description allowed at least something within the scope of the claims to be made. However, in Australia the best mode sits as a separate requirement–and this is where Servier ran into problems.

It was established that, prior to the filing date of the Patent, Servier scientists had generated the arginine salt of perindopril on at least two different occasions using specific sets of parameters including solvent types, heating, mixing protocols etc. While the specific parameters could certainly be described as representing classical salification approaches, the patent specification failed to disclose any of these specific parameters, instead leaving it to the person of skill in the art to ascertain these, albeit that this may only have been a routine matter with minimal trial and error involved.

The earlier decision thus resulted in a finding that the Patent did not describe the best method of performing the invention. Servier then applied to amend the specification to include a description which would satisfy the best mode requirement. Under the Patents Act 1990 such an amendment, even post-grant, was permissible so long as it didn’t result in anything new being claimed. Apotex, not surprisingly, objected to the proposed amendment which was addressed in this most recent Federal Court decision.

The court found that the proposed amendment was allowable under the relevant provisions of the Patents Act 1990.  But the court’s power to allow the amendment is discretionary and was, surprisingly, refused.

Through evidence discovery it had emerged that during the examination process the Australian patent attorney handling prosecution had recommended to Servier that a specific method for the production of the arginine salt of perindopril be inserted into the specification. Servier had responded that they felt the general classic salification description was enough and they did not see any need, at that time, to add further detail. The court did not suggest that Servier were being underhanded in not including the more specific synthesis parameters at that time and in fact accepted that the Servier employee responsible for the matter (Dr Jaguelin) genuinely believed that the further detailed description was not warranted.

The court found, in short, that Servier had acted appropriately and promptly in requesting the amendment but that the court’s discretion would not be granted because Dr Jaguelin’s decision amounted to “an error on her part” and “a calculated risk about a potentially very valuable asset”. The court set out that the contract between Servier and the public required of Servier a description of the best method known to them for preparing perindopril arginine and that “the damage to the public interest involved in Servier’s failure to disclose the…methods in the complete specification…was not reasonable and outweighs the proprietorial interest of Servier in being able to save the patent from revocation…”. All this was in light of the fact that Dr Jaguelin was considered to have acted in good faith and that her “error’ really only became apparent in hindsight.

This is a harsh reminder of the potential consequences in Australia of not disclosing the best mode within the specification at the filing date. Servier are appealing this decision, and it will not be surprising if they have some success.  But clearly this issue is best avoided in the first place.

Under the current law in Australia (brought into effect by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 (Cth)) the situation is even more challenging. Best mode is still a consideration during examination and is available as a ground of revocation, but the provisions on the allowability of amendments have been changed such that new matter, such as the proposed Servier amendment to add the best mode description would have been, can no longer be added to the description, even if it is not claimed.

Patent applicants in Australia, and in other jurisdictions where the applicants have a commercial interest in Australia, should be aware of the best mode requirement in Australia and ensure that the best method of practicing the invention is included in the specification at the time of filing.  Under our new laws, failure to disclose the best method cannot be corrected later and can be fatal to the validity of the patent. Best mode rarely arises in court challenges, and is even more rarely successful, due to the difficulty in objectively proving that the patent applicant was aware of a preferred method of working the invention which was not included in the specification; however, this case is a timely reminder that the consequences of failing to include it can be dire.