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Australia – Running A Risk: Servier’s Perindopril Arginine Patent Found To Lack Best Method.

23 April, 2014

 


Apotex Pty Ltd v Servier Laboratories (Aust) Pty Ltd [2013] FCA 1426

 
What You Need To Know

 

  • The Federal Court of Australia has found that the patent for perindopril arginine, marketed by Servier under the brand name COVERSYL, failed to disclose the best method of performing the invention known to the patentee.
  • Justice Rares found that two specific methods known to Servier were better than the “generalised and unspecific” method disclosed in the patent because they eliminated the risk that the skilled addressee would be put to expensive trial and error in ascertaining the details of the method for themselves.
  • Although found invalid on this ground, however, it appears that revocation of the patent may not necessarily follow and Servier has applied to amend the patent to rectify the defect.

 
The Proceedings

 
Apotex Pty Ltd brought proceedings to challenge the validity of Australian Patent 2003200700 (the Patent), held by Les Laboratoires Servier and exclusively licensed to Servier Laboratories (Aust) Pty Ltd. The Patent claims the arginine salt of the drug perindopril, its hydrates, its pharmaceutical compositions and a method of treatment using those compositions. Perindopril is used in the treatment of hypertension and heart failure.

 
Servier possessed an earlier patent claiming the erbumine salt of perindopril and had marketed tablets containing perindopril erbumine under the brand name COVERSYL between 1992 and 2006. Following the expiry of the earlier patent, Servier marketed tablets containing perindopril arginine under the same brand name.

 
Apotex asserted invalidity of the Patent on the grounds of lack of novelty, lack of inventive step, lack of fair basis, lack of disclosure of best method and for false suggestion.

 
Justice Rares found Apotex had established that the Patent failed to disclose the best method of performing the invention known to Servier. Apotex was unsuccessful on the other four asserted grounds of invalidity.

 
Lack Of Best Method

 
Section 40(2)(a) of the Patents Act 1990 (Cth), as it applied to the Patent, required that a complete patent specification “describe the invention fully, including the best method known to the applicant of performing the invention”. The requirement for disclosure of best method is a distinct requirement to that of sufficiency, which requires that the specification provide sufficient description to enable the skilled addressee to perform the invention without new inventiveness or prolonged study.

 
The evidence established that Servier had made perindopril arginine twice, first in 1986 and again in 1991, with the methods used on each occasion differing in their choice of various parameters, including solvent, heating rate, mixing rate and crystallisation vessel. Both of these methods were examples of “classical” methods of salification.

 
The Patent specification, however, did not disclose the detailed parameters of the salification method used by Servier, stating only that perindopril arginine had been prepared “according to a classical method of salification of organic chemistry”.

 
In arguing for the validity of its patent, Servier contended that Apotex, to establish lack of best method, was required to prove that a skilled addressee following the general description of “a classical method of salification” would have achieved a worse result than that achieved using Servier’s 1986 or 1991 method, and that Apotex had failed to prove this.

 
Justice Rares rejected this argument. His Honour found that the specific methods known to Servier were better than the “generalised and unspecific” method disclosed in the Patent because they eliminated the risk that a worse result would be obtained and therefore saved the skilled addressee from potentially expensive trial and error. Referring to the inventor employed by Servier, his Honour said that “as a person skilled in the art, he knew that there were many alternatives available from which to choose and that some were likely not to be as good as others”. In his Honour’s opinion, the general method disclosed by Servier was “wholly inadequate to describe the best method, or any substantive content of any particular classical method that the patentee knew of performing the invention.”

 
This decision illustrates that the level of detail disclosed by a patentee in its specification is relevant not only to considerations of sufficiency, but also to the separate requirement under Australian law to disclose the best method known to the patentee of performing the invention. In the present case, Apotex did not assert that Servier had disclosed insufficient detail to enable the skilled addressee to perform its invention, but rather that the generality of description constituted a failure to properly disclose the best method known to Server of performing that invention. In His Honour’s words, the requirement to disclose best method “is a fundamental aspect governing the grant of a patent” which “supplements the co-ordinate requirement in s 40(2)(a) that the complete specification also describe the invention fully”.

 
Final Orders

 
Justice Rares stated at the conclusion of his judgment that his finding as to lack of best method “raises the question of what relief should be granted under s 138(3) of the Act.” This comment foreshadowed that orders for revocation of the Patent did not automatically follow. Servier has since applied to amend its specification to overcome the established ground of invalidity, and a timetable has been set for the progress of that amendment application.

 

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For further information, please contact:

 

Ben Miller, Partner, Ashurst
[email protected]


Mark Straton, Ashurst
[email protected]

 

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