Lilly sued Novopharm for infringement under Canadian Patent No. 2,041,113, a selection patent for the compound olanzapine (sold under the brand name Zyprexa), owned by Lilly. Olanzapine is used to treat schizophrenia.
Novopharm argued that the ‘113 Patent is invalid. A Federal Court judge (the trial judge) agreed with Novopharm and dismissed Lilly’s action. The Federal Court of Appeal reversed.
On appeal, the question raised by the parties was:
Do the conditions for a valid selection patent constitute an independent basis upon which to attack the validity of a patent?
Lilly already obtained Canadian Patent No. 1,075,687, a genus patent described by the court as covering “approximately 15 trillion compounds predicted to be useful in the treatment of mild anxiety and certain kinds of psychotic conditions, such as schizophrenia and acute mania. The ‘687 Patent expired 15 years ago.
The ‘687 Patent encompassed, but did not disclose, olanzapine. The trial judge concluded that olanzapine fell within the “most preferred” compounds. The ‘687 Patent specifically disclosed flumezapine, ethyl flumezapine and ethyl olanzapine.
Further research was conducted on some of the ‘687 Patent’s compounds, one of which was olanzapine. In 1989, clinical trials began with patients. Lilly decided to file the ‘113 Patent, which characterizes olanzapine as a selection from the class of the ‘687 Patent. The patent for olanzapine was filed in Canada on April 24, 1991 and the ‘113 Patent issued July 14, 1998.
In the reasons for judgment, the trial judge identified the ‘113 Patent’s stated advantages over both the ‘687 Patent and other antipsychotic drugs, including lower incidence of liver enzyme elevations compared to flumezapine; lower CPK levels than flumezapine; lower ESP liability than flumezapine; and no increase in cholesterol compared to ethyl olanzapine.
The trial judge reasoned that if these advantages amounted to a substantial advantage secured by the drug (or a substantial disadvantage avoided in comparison with the genus patent), if they were known or predicted at the time of filing, and if they were adequately disclosed, the ‘113 Patent would be a valid selection patent.
The trial judge concluded that there was insufficient evidence of the advantages identified by the ‘113 Patent. Specifically, the trial judge determined: the stated advantages were not substantial and peculiar; a person skilled in the art (POSITA) would not be able to appreciate any inventive difference between the ‘687 Patent and the ‘113 Patent; the test for sound prediction was not met; Lilly had very little idea about what olanzapine’s effect was likely to be; and the ‘113 Patent did not meet the requirements for adequate disclosure.
Although not restricted to chemical patents, selection patents more commonly arise in that context. Simply stated, the originating (or genus) patent typically refers, in general terms, to a group of products or processes from all of which a particular result (or results) may be obtained or predicted. If a property, quality or use in relation to one or more members of the genus is subsequently discovered, that discovery may be an invention giving rise to a valid selection patent. As explained in Pfizer and Sanofi, selection patents exist to encourage researchers to further use their inventive skills so as to discover new advantages for compounds within the known class. A selection patent can be claimed for a selection from a class of thousands or for a selection of one out of two.
In Sanofi, the characteristics of a valid selection patent are described as follows:
- There must be a substantial advantage to be secured or disadvantage to be avoided by the use of the selected members;
- The whole of the selected members (subject to “a few exceptions here and there”) possess the advantage in question;
- The selection must be in respect of a quality of a special character peculiar to the selected group. If further research revealed a small number of unselected compounds possessing the same advantage, that would not invalidate the selection patent. However, if research showed that a larger number of unselected compounds possessed the same advantage, the quality of the compound claimed in the selection patent would not be of a special character.
Lilly argued that the trial judge erred by creating an “illegitimate amalgam by merging the doctrine of sound prediction of utility with obviousness and sufficiency and in the process required Lilly to provide proof of the inventive step (i.e. the advantages) in the disclosure.” In Lilly’s view, the “selection” issue goes to the question of obviousness and is properly addressed as part of that inquiry.
The Federal Court of Appeal felt likewise:
In my view, a challenge directed to a determination that the conditions for a selection patent have not been met does not constitute an independent basis upon which to attack the validity of a patent. Rather, the conditions for a valid selection patent serve to characterize the patent and accordingly inform the analysis for the grounds of validity set out in the Act – novelty, obviousness, sufficiency and utility. In short, a selection patent is vulnerable to attack on any of the grounds set out in the Act.
Notably, the Act contains no reference to invalid selection.
On consideration, I think it would be unwise to endeavour to state in definite language all the conditions on which a selection patent must depend; for after all a selection patent does not in its nature differ from any other patent and is open to attack on the usual grounds of want of subject-matter, want of utility, want of novelty and so forth.
Application to this Case:
I have concluded earlier that a determination that the conditions for a selection patent have not been met does not constitute an independent basis upon which to attack a patent’s validity. A selection patent is the same as any other patent. Its validity is vulnerable to attack on any of the grounds set out in the Act. It necessarily follows that the trial judge erred in determining the validity of the ‘113 Patent on the basis that he did. That is not to say, however, that his analysis is not relevant to the issue of utility, or other grounds of validity.