This paper discusses some of the principles arising from recent cases, from both the perspective of patent agents interested in avoiding legal challenges to patent agents interested in avoiding legal challenges to patent applications prosecuted by them, and also from the perspective of patent litigators as what is needed to be alleged, proved and done at trial if a successful attack on validity is to be made out in regard to an issued patent under the Patent Act.

This paper was presented at the Intellectual Property Law Update program which was held in Edmonton on February 8, 2011 and in Calgary on February 10, 2011.