6 years after our “Lessons about patent amendment” post the Federal Court has handed down another decision in the same proceeding (Apotex v Les Laboratories Servier (No 4) [2015] FCA) aboutamending a patent under s 105 of the Patents Act. The patent at the centre of these proceedings relates to Servier’s blood pressure medication, perindopril. This time the Court provided guidance on the exercise of discretion to permit amendment of a granted patent to cure a section 40(2)(a) defect – that the patentee had not disclosed the best method of performing the invention that was known to it.

As a brief introduction, in late 2013 Rares J found Servier’s complete specification did not comply with s 40(2)(a) because it failed to disclose the best method of performing the invention . His Honour found use of the words “prepared according to a classical method of salification of organic chemistry” when referring to the method of producing the subject L-arginine salts to be “too generalised”.

This gave rise to Servier’s application to amend the complete specification under s 105 to include specific descriptions of multiple methods to produce the L-arginine salts that were known to it at the time of filing.

The application was ultimately refused on grounds that the failure to disclosure the best method of performing the invention which was inconsistent with the public interest in full disclosure outweighed the proprietary interests of Servier being able to save the patent from revocation. Crucially, at the time of filing Servier was advised to include the best methods that it now sought to include, however Servier took a “see later” approach which Rares J found to be a calculated risk.

The decision provides some lessons about post grant amendment:

  • s 105(1) is available to cure any ground of revocation specified in s 138(3) (subject to exclusions contained in s 102);
  • ‘any ground’ includes amending the description of the best method as required by s 40(2)(a);
  • the description of the best method can be amended under s 105(1) after the filing of the complete specification, and even after the grant of the patent;
  • the patentee’s state of mind is relevant to the exercise of discretion under s 105(1);
  • the circumstances surrounding the patentee’s decision to make the application in the original form will be relevant to the Court’s consideration of whether the patentee should be allowed to amend;
  • the power conferred by s 105(1) gives the Court an unfettered discretion to permit or refuse such amendment;
  • the patentee has an obligation of candour as to its reasons for seeking the amendment and bears the onus of establishing the case supports the exercise of the discretion in all the circumstances; and
  • in exercising discretion under s 105(1) the Court will consider the effect of permitting or refusing the application on the public at large as well as any effect it may have on the rights and liabilities of the patentee and the other parties to the litigation.

This may not be the final word on the subject as the decision may be appealed.