Patents

The Full Federal Court of Australia recently found that the majority of Wyeth's patent claims covering a method of administering an antidepressant compound were invalid, based on a finding that the patent was not entitled to its earliest priority date. The decision highlights the care required when amending patent claims to ensure they are not broadened to the extent that they cease to be fairly based on the specification and any priority documents.

Once their compound patents have expired many blockbuster drugs remain protected by secondary 'method of treatment' patents. The validity and enforceability of these secondary patents can be less certain in many jurisdictions. In Sanofi-Aventis Australia Pty Ltd v Apotex Pty Ltd (No.3) [2011] FCA 346, the Federal Court found that the secondary patent protecting Sanofi-Aventis' blockbuster leflunomide drug was valid and infringed – a surprising outcome, at least initially, based on the facts of the case.