Apotex recently failed in its attempt to have Eli Lilly’s patent covering antipsychotic drug Zyprexa revoked by the Federal Court.  In his judgment (Eli Lilly v Apotex), Justice Middleton considered two relatively fresh issues – the proper approach to ‘selection patents’, and the significance of differences in the naming of chemical formulae.

Eli Lilly commenced the proceeding against Apotex in December 2009, alleging infringement of its patent for olanzapine (the active ingredient in Zyprexa).  On 15 December 2009 Apotex was restrained from manufacturing and selling its generic olanzapine products until the determination of the proceedings or the expiry of the patent.  While the trial took place in October – November 2011, as a result of the March 2012 expiry date of the patent Apotex was able to enter the market before Justice Middleton’s decision was delivered.

Apotex argued that the patent should be revoked on almost all available grounds, but Justice Middleton rejected those grounds and ultimately found the patent valid.

Novelty and selection patents

In his judgment, Justice Middleton dealt with what he described as an unsettled area of Australian patent law – ‘selection patents’.  A selection patent claims as an invention the selection of specific elements, chosen from a larger class or range of elements, which have certain benefits or desirable features.  They most commonly arise in the context of chemical patents.

Apotex argued that Eli Lilly’s patent was invalid on the established principles of lack of novelty – namely that earlier Eli Lilly patents, which were “genus patents”, anticipated the patent in suit because they encompassed olanzapine.  Eli Lilly’s genus patents were obtained in the 1970s and claimed a broad class of antipsychotic compounds called thienobenzodiazepines.  Olanzapine is a member of this class, although it was not specifically disclosed in the genus patents.

Eli Lilly argued that even if olanzapine was disclosed in the genus patents, this did not destroy novelty as olanzapine had been legitimately “selected” from the genus patents to give rise to the patent in suit on the basis of its superior properties (thus making it a “selection patent”).

This argument is particularly interesting as there is conflicting authority over whether the concept of ‘selection patents’ forms part of Australian patent law.  Justice Middleton defined a ‘selection patent’ as “a patent for an invention that is selected from a broader invention disclosed in a prior publication”.  The judge examined a large number of cases on this issue –  including the seminal decision of the UK High Court in Re IG Farbenindustrie AG’s Patents (1930) 47 RPC 289 and the decisions of Crennan J in ICI v Commissioner of Patents (2004) 213 ALR 399 and Gyles J in Apotex v Sanofi-Aventis (2008) 78 IPR 485.  He also referred to a number of Australian Patent Office decisions.

Justice Middleton identified the following as relevant principles for any invention legitimately selected from a prior publication:

  • the selection must be based on some substantial advantage to be secured (or some substantial disadvantage to be avoided) by the use of the selected member/s of the class disclosed in the prior publication;
  • all of the selected members must possess that advantage;
  • the selection must be in respect of a quality of a “special character” that can fairly be said to be peculiar to the selected group; and
  • the specification must define in clear terms the nature of the special characteristic possessed by the selection.

Ultimately, Justice Middleton found that the olanzapine patent was novel by applying established novelty principles, as the earlier genus patents did not offer sufficiently clear disclosure of olanzapine.  His Honour stated that if that he were wrong on that point, then Eli Lilly’s invention would still be valid under the principles of selection patents (despite declining to determine conclusively whether these principles formed part of Australian patent law).  Justice Middleton was satisfied that this was a case where a patentable invention could be found in the mere selection of a single compound from a broader class.

Infringement

Apotex admitted its products contained olanzapine, but argued it did not infringe because the substance described in Eli Lilly’s patent was not olanzapine.  In other words, there was a nomenclature dispute about the relevant chemical formulae. According to Apotex, Eli Lilly’s claims did not identify ‘olanzapine’ because the relevant substance did not meet the strict nomenclature principles established by the International Union for Pure and Applied Chemistry (“IUPAC”).  Since Eli Lilly had failed to use this (allegedly correct) name in its patent, Apotex contended its product could not infringe.

Justice Middleton wasn’t satisfied with Apotex’s argument, however, finding that a skilled addressee would clearly identify olanzapine as the compound claimed, in part because of unambiguous references elsewhere in the specification. Apotex’s products were held to infringe.