Double Patenting And Divisionals In Canada: Evolving Strategies For Applicants

Double patenting and unity of invention in divisional practice remain central issues in patent prosecution in different jurisdictions, but the strategies for addressing them differ sharply between Canada, the United States and Europe. The basic doctrine against double patenting prevents the same applicant from obtaining more than one patent that claims the same subject-matter or, in many jurisdictions, claims that are not patentably distinct, with the precise tests and any cures determined by local law. In the United States, terminal disclaimers are available to cure non-statutory obviousness-type double patenting. In Europe, unity requirements are strictly enforced, and the EPO may refuse an application on the grounds of double patenting, but this is limited to "same subject-matter" refusals. In Canada, however, the critical factor is whether a divisional application was filed "on the direction of the Commissioner". Subsection 36(2.1) of the Patent Act makes this a