In an appeal from a Patent Office decision to extend the time to file an application for extension of the term of a pharmaceutical patent, the Administrative Appeals Tribunal (AAT) recently upheld

  • the power of the Patent Office to grant such an extension of time outside the prescribed period, and
  • the use of the discretionary powers of the Patent Office to award a very long extension.

The decision is the most recent in the ongoing dispute between H Lundbeck A/S and several generic drug manufacturers over the correct expiry date of Australian Patent 623,144, covering Lundbeck’s anti-depressant pharmaceutical escitalopram (+ citalopram), marketed as LEXAPRO™.

A request for a 121-month extension of time within which Lundbeck could request an extension of the term of the patent has been affirmed. Without the extension the LEXAPRO™ patent would have expired on 13 June 2009, but with the extension it expired on 9 December 2012. The extended term was important for both parties because the generic manufacturers had begun selling their own versions of LEXAPRO™ on or around 13 June 2009.

History of the Dispute

LEXAPRO™ was listed on the Australian Register of Therapeutic Goods (ARTG) on 16 September 2003 and the term of the patent covering it had been extended by the Patent Office until 13 June 2014 based on this date. This extension of term was revoked on 11 June 2009 by the Full Court of the Federal Court of Australia because

  • CIPRAMIL™, a racemate mixture of (+) and (-) citalopram, contained (+) citalopram, and
  • Lundbeck’s extension of term application for LEXAPRO™ was not based on the first regulatory approval date of goods that contain or consist of (+) citalopram.

The Full Court also held that the LEXAPRO™ patent claims were valid and would be infringed by the respective generic products.

On 12 June 2009, one day before the LEXAPRO™ patent was to expire; Lundbeck filed an application for an extension of time to file an extension of term application based on its earlier ARTG listing of CIPRAMIL™. Nevertheless, the generic manufacturers went ahead and launched their own versions of LEXAPRO™, and opposed the extension of time request. These manufacturers took a calculated risk, given the likely damages award should the extension of time be granted and the term of the patent extended

AAT Review

The AAT had two questions to consider.

  1. Does the legislation allow for an extension of time request for an extension of term of a patent?

The AAT held that if an application for an extension of term is made before the expiry date of the subject patent, the legislation makes available the discretion to grant an extension of time to satisfy all requirements of a patent term extension request. This is consistent with:

  • the plain reading of the Patents Regulations and the Patents Act, and
  • the interpretation adopted in the Patent Office Manual of Practice and Procedure.
  1. If so, do the facts of this case justify a discretionary grant of an extension of time of over 10 years?

The justification for Lundbeck’s extension of time request was an error in considering that the extension of term of the patent could be based only on the registration of LEXAPRO™ (and not CIPRAMIL™) because CIPRAMIL™ did not fall within the scope of the claims of the LEXAPRO™ patent. It therefore did not contemplate applying for an extension of term of the LEXAPRO™ patent based on the marketing approval of CIPRAMIL™.

It is a requirement that once an error or omission has been identified, an application for an extension of time be lodged without undue delay. The generic manufacturers argued that Lundbeck delayed its request for an extension of time, despite a suggestion to do so based on the CIPRAMIL ARTG date on 14 July 2005 from its Australian patent attorney and as a consequence, should not be entitled to the grant of a discretionary extension of time.

The AAT found that:

  • It was reasonable for Lundbeck to believe that LEXAPRO™ had been accorded the correct and appropriate extension of term to 13 June 2014. (It was almost 10 years later that the basis for the extension of term was held to be incorrect in law). The reasonableness of Lundbeck’s belief was supported by evidence that it was widely held among the Australian patent profession that the Federal Court was incorrect in finding that the CIPRAMIL ARTG listing date was the proper basis for an extension of the LEXAPRO™ patent term.
  • In relation to undue delay, the patent attorney’s ‘letters setting out preliminary views, comments and possible strategic suggestions [did] not support a conclusion that the conduct of Lundbeck was in any way unreasonable in not making an application for an extension of time at that point’.

The decisions of the Patent Office and the AAT have been appealed to the Federal Court.