Mind the Gap – Patent term extension creates problem for generic pharmaceutical industry

Assorted pills and capsules

The latest chapter in the extensive and longstanding litigation around Australian patent no. 623144, owned by Danish pharmaceutical company H. Lundbeck A/S [1], highlights a practical difficulty for generic manufacturers.

The Decision

Lundbeck sought to extend the term of the patent, but did so only just before the patent expired. This was well beyond the usual deadline, and so Lundbeck had to seek an extension of time in order for the application for extension of term to be considered. Several generic manufacturers, including Sandoz, launched products after the patent expired but before the application extending the time in which to apply for an extension of term was considered. Since they launched at a time when Lundbeck had no patent rights, Sandoz argued that they should have been protected from patent infringement once rights were restored. However, the Court held that the extension of term should be retrospective., and so Sandoz infringed the patent.


This action arises in unusual circumstances. The anti-depressant drug citalopram is a racemic mixture of the two enantiomers, the (+) enantiomer and the (-) enantiomer. Lundbeck held patents covering the racemic mixture and had marketed the racemic mixture as CIPRAMIL. The patent in suit claims the more-effective (+) enantiomer. Lundbeck sought an extension of term based on the registration of the (+) enantiomer, as LEXAPRO, on the Australian Register of Therapeutic Goods (ARTG). In an earlier chapter in this saga, it was established the application for extension of term should have been based on the earlier registration on the ARTG of citalopram, as citalopram (CIPRAMIL) contains the (+) enantiomer, and not on the registration of the (+) enantiomer (LEXAPRO) on the ARTG [2].

Lundbeck made a new application for extension of term on 12 June 2009, the day before patent no. 623144 expired. This time the application for extension of term was based on the ARTG registration for CIPRAMIL. This was accompanied by an application for extension of time (since the application should have been made within 6 months of the date of the ARTG registration of CIPRAMIL, making the deadline 26 July 1999) which had to be successful for the extension of term to be approved. A delegate of Commissioner held that the extension of time was allowable since the original deadline for making the application for extension of term was missed due to a genuine misunderstanding of the law on the part of the patentee.

Sandoz released their generic product to the market on 15 June 2009, just two days after the expiry of Lundbeck’s patent, and only three days after the application for extension of term was made. The Commissioner of Patents approved an extension of the patent term on 25 June 2014 [3]. Lundbeck filed patent infringement proceedings in the Federal Court of Australia on 26 June 2014.

Mind the Gap

In this case the Federal Court held that a decision regarding the extension of the term of a patent could be delivered following expiry of the patent, and the effect of that delivery is retrospective. Although the application for extension of term was filed out of time, this was able to be rectified by applying to extend the deadline because the failure to file in time was due to an “error or omission” on the part of the patentee. Although Sandoz launched their product at a time when it seemed Lundbeck had no patent rights, there was no gap in protection since the patent never ceased nor needed to be restored.

This may be contrasted with the situation where a patent is restored when, for example, a renewal fee is paid out of time. In these circumstances, since the patent did temporarily cease, steps taken by another party to exploit the patented invention in the “gap” period will not open the party to infringement proceedings.

The impact on generics

Generic manufacturers who seek to launch immediately after the expiry of a patent should take note of the possibility that an application for an extension of term can be made at a late date in Australia if some error or omission lead to this not being done within the prescribed time. Such extensions of patent terms will have retrospective effect if granted after the expiry of the patent.

It is understood that the decision is under appeal.


[1] H. Lundbeck A/S v Sandoz Pty Ltd [2018] FCA 1797


[2] Alphapharm Pty Ltd v H Lundbeck A/S [2014] HCA 42


[3] Alphapharm Pty Ltd, Apotex Pty Ltd, Aspen Pharma Pty Ltd, Sandoz Pty Ltd v H Lundbeck A/S [2014] APO 41