Drug: Xalatan® latanoprost
The Court of Appeal first considered that the Applications Judge construed the patent in accordance with her construction in a previous proceeding, which was upheld by the Court of Appeal. The Court of Appeal in the within case held that Apotex was not a party to the previous proceeding and was not prevented from advancing a different construction based on an issue that was not raised in the previous proceeding.
The Court of Appeal found that the Applications Judge erred in her construction of the promise of the patent. In particular, the Court of Appeal construed the promise of the patent to be related to chronic use of the compound for the treatment of glaucoma. The Court of Appeal indicated that it is an error to construe the promise of the patent without consideration of the nature of the disease to which it relates. Therefore, as expert evidence indicated that the treatment of glaucoma requires chronic treatment, the promise should be construed accordingly.
As a result of its construction, the Court of Appeal found that there was no demonstration of utility in the patent. The Court of Appeal held that utility would be demonstrated if the patent disclosed studies of chronic administration of the compound. The Court of Appeal found that the evidence demonstrated at the time of the patent application that the inventors had conducted single dose studies on animals and healthy humans and not patients with glaucoma or on a chronic basis. As a result, the Court of Appeal found that the utility of the patent was not based on a demonstration but on a prediction. Considering the three requirements for a prediction to be sound, the Court of Appeal was not persuaded that the inventors had an articulable and sound line of reasoning between the factual basis, namely the single dose studies, and the promise of the patent. Accordingly, the appeal was allowed.