Direct Evidence of Lack of Utility Is Useful

AstraZeneca Canada Inc v Pharmascience Inc / esomeprazole (NOC) 2012 FC 1189 O’Keefe J

            2,290,531 NEXIUM

This decision turned entirely on the evidence regarding utility, and no new points of law appear to be raised. The patent at issue claims an enteric coated pharmaceutical formulation of omeprazole using hydroxypropyl methylcellulose (HPMC) with a specified cloud point (CP) as a separating layer between the enteric coating and the active ingredient. The patent asserts that it has “surprisingly” been found that the CP of HPMC affects the rate of release of omeprazole. Pharmascience’s evidence was that not only was this surprising, it was incredible and false. The expert evidence for Pharmascience was to the effect that the HPMC was merely a separating layer and “could not function to control the rate of drug release” [40].

The case therefore turned primarily on the evidence on the issue of utility. O’Keefe J held that Pharmascience had met its evidentiary burden and put this allegation into play, and the burden therefore lay with AstraZeneca to show on the balance of probabilities that the patented invention was useful [172]. On the facts, O’Keefe J held that the experiments disclosed in the patent were sufficient to carry this burden [191]. Ultimately, Pharmascience’s case failed because AstraZeneca provided direct evidence that the invention worked as claimed, while Pharmascience did not provide any direct evidence to the contrary. There was considerable evidence from Pharmascience’s experts that it was very unlikely that the CP should affect the rate of drug release, but that only goes to show how surprising it is if the patent’s claim is true. Pharmascience did not provide evidence of direct tests of rate of release of formulations with the different CPs, as disclosed in the patent [193]. In the absence of evidence that the invention actually did not work, as opposed to evidence that it was unlikely to work, the patentee’s evidence that it did work carried the day.

Pharmascience also argued that the patent in question was not an invention on the basis that it merely ascertained the properties of a known substance [173ff]. O’Keefe J dismissed this argument. The patent did not merely measure the CP, but also disclosed how to use that knowledge to manufacture a superior product [176]. (Selecting HPMC with the disclosed CP would reduce product discard [97].)

On the fact O’Keefe J held that disclosure was adequate. This was purely a matter of the skilled person’s understanding of the disclosure, and no novel points of law were raised.

Finally, O’Keefe J dismissed Pharmascience’s argument that the invention was obvious. This follows directly from his holding on the evidence that the CP does affect rate of release, as Pharamscience’s own evidence established how surprising this was.