Unpredictable but Not Surprising - The Federal Court of Canada Clarifies the Application of the Obvious-to-Try Test

On August 3, 2010, the Federal Court released reasons in Novo Nordisk Canada Inc. et al. v. Cobalt Pharmaceuticals Inc. et al. (2010 FC 746; "Novo Nordisk")) finding Cobalt's allegation of obviousness justified with respect to Canadian Patent No. 2,111,851. The patent covers repaglinide (an (S) enantiomer), its use for the treatment of Type 2 Diabetes, and processes to make it.

Novo Nordisk is an important case both from legal development and commercial perspectives. The Federal Court has made clear that scientific knowledge evolved after 1987, the date considered by the Supreme Court of Canada ("SCC") in Sanofi,1 and that by 1991 it was the state of the art to separate and test enantiomers of racemic potential drugs. This decision refines the obvious-to-try test set out by the SCC and suggests a review of all enantiomer patents applied for in or after 1991.

The Decision in a Nutshell

The patent involved in this proceeding (the "851 Patent") essentially covers the enantiomer repaglinide. Repaglinide is sold under the brand name GLUCONORM".

Enantiomers are mirror image molecules that cannot be superimposed on each other (think of right and left hands). They are normally synthesized together, as a "racemate", and one cannot know how each of the two enantiomers comprising the racemate (denoted (S) and (R)) will act in the body until it has actually been made and tested. Activity and toxicity can be different as between the racemate, the (S) enantiomer and the (R) enantiomer.

Unlike other recent cases, the racemate comprising repaglinide was never approved or marketed as a drug product, although the racemate had been identified in a previous "genus" patent covering numerous compounds, as well as a patent covering new solid forms of the racemate.

Nonetheless, Cobalt alleged repaglinide to be obvious, and the 851 Patent to be invalid on this and other grounds.2 The Court agreed and found the 851 Patent obvious to try.

This is only the second decision known to the author in which the Court found allegations of invalidity of an enantiomer patent justified.3

Refining the Obvious-to-Try Test

In the Sanofi case, the SCC dealt with an enantiomer patent and in that context, set out the obvious to try analysis applied by the Court to repaglinide in this case. The obvious to try factors include asking whether it is more or less self-evident that what is being tried (i.e. the invention) ought to work.

In answering this question, the SCC stated:

As I have...