When it comes to patents, best method is best
Under Australian law, it is a requirement for the patent applicant to disclose in the patent specification that is filed, the best method for performing the claimed invention that is known to the applicant at the filing date of the application.
Many patent applicants (and would be patent applicants) have expressed a desire to potentially ‘have their cake and eat it too’ by filing a patent application with a view to obtaining a monopoly for the claimed invention, but to withhold better or superior embodiments or features the invention so that these are not published in the patent specification.
However, if the best method for performing the invention that is known to the applicant at the time of filing the application is not disclosed in the patent specification that is filed, it can result in invalidity of the patent.
There have been two recent cases that have reinforced this aspect of the law, and the outcome of these cases led to the patents in question being revoked.
The two cases are Les Laboratoires Servier v Apotex Pty Ltd  FCAFC 27 (‘Servier’) and the more recent Sandvik Intellectual Property AB v Quarry Mining & Construction Equipment Pty Ltd  FCAFC 138 (‘Sandvik’).
The omission of sufficient description of the best method for performing the claimed invention by the patent applicants led the Court to revoke the respective patents, ultimately finding that the two patents were invalid for failing to meet the best method requirement.
The ‘Servier’ Case
The Full Federal Court found in the Servier case that the patent specification failed to describe the best method known at the filing date of performing the invention to prepare the arginine salt of perindopril (perindopril arginine), its hydrates and pharmaceutical compositions thereof.
Perindopril, an angiotensin-converting enzyme (ACE) inhibitor, is used for the treatment of hypertension and related conditions.
Due to the inherent instability of perindopril, the preparation of a suitable pharmaceutical form for administration was problematic. The patent specification indicated that the arginine salt surprisingly exhibited improved stability whilst maintaining good bioavailability, and this was the invention for which patent protection was sought.
With regard to the preparation of perindopril arginine, the patent specification simply stated that it was “prepared according to a classical method of salification [salt formation] of organic chemistry”; that is, a standard method known in the art. No other details relating to the preparation of the claimed arginine salt were provided, and no specific method was referred to in the specification.
The Court determined that the nature and extent of the disclosure required to satisfy the best method requirement depends on the nature of the invention itself.
In some cases, this means that there may be no requirement to provide a method of using or making a product in order to satisfy the best method requirement. However, this will only typically apply where the claimed invention is for a product.
In this case, the particular salt formation and the methodology to prepare the specific salt had more importance than might be the case where the claimed invention was a product for which these characteristics were irrelevant.
Accordingly, by omitting sufficient description of the successful methods used to prepare perindopril arginine, the Court found that Servier had failed to describe the best method known at the filing date of performing the invention. As such, the Court found the patent invalid for failing to meet the best method requirement.
The ‘Sandvik’ Case
The patent at issue in Sandvik was directed to an extension drilling system for use in drilling bores, in particular for coal mining. The Court found that the applicants were aware at the time of filing the application that an improved water-sealing arrangement that had been developed was critical to the efficacy and quality of the ultimate form of the invention.
In omitting this information from the patent specification, the Court found that applicant had failed to describe the best method known to it at the filing date.
During the Hearing, the Court heard evidence that in the course of development the drilling system one of the “real issues” to be addressed was the design of an effective water seal. Indeed, there were technical drawings prepared which pre-dated the filing of the patent application that described an improved sealing arrangement for use with the drilling system. However, these technical drawings were not included in the patent specification, nor was there any disclosure of the improved sealing arrangement mentioned in the specification at all.
The Court found that the improved seal did not amount to some minor or incidental dimension, but was in fact “the ultimate evolution of the seal” and “a superior design”, and so should have been included in the specification as the best method known to the applicants at the time of filing the application.
These two cases have clarified the scope of the best method requirement, and serve as a reminder that it is important for the specification to thoroughly disclose the invention, and most importantly, the best method for performing the claimed invention that is known to the applicant at the time the application is filed.
In particular, these cases provide a warning to patent applicants to ensure that the description of embodiments in a patent specification is updated prior to filing (especially where the application may claim priority to an earlier filed patent application that may not have been as advanced as the invention is at the time the later application is filed), to ensure that the best method known to the applicant is clearly disclosed.
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