Wednesday, January 23, 2013

Double Patenting in Canada: Change in Canadian Patent Office Practice?

Wednesday, January 23, 2013
As discussed in a previous post in this blog (, Canadian jurisprudence clearly sets forth a prohibition against double patenting. There are two branches of double patenting in Canada: (1) “same invention double patenting” which applies in situations where the claims are identical or conterminous and (2) "obviousness double patenting” which prohibits the issuance of a second patent with claims that are not "patentably distinct" from those of the earlier patent.  As terminal disclaimers are not available in Canada, care must be taken to ensure that the subject matter claimed in any voluntary divisional applications (i.e. not filed in response to a restriction requirement) is patentably distinct from the claims of the parent.

It has been my experience in the past, that Canadian Patent Examiners simply issue a double patenting objection to a voluntary divisional application when they believe that the claims of the divisional application are not directed to patentably distinct subject matter.  While I am aware of threats in the past of “denying divisional status” to an application unless the claims are amended to be directed to patentably distinct subject matter, I was not aware of the Canadian Patent Office following through with such a threat until recently.  In a recent case that I am familiar with, the Canadian Patent Office, instead of just issuing a double patenting objection against the claims of a voluntary divisional application, also “denied divisional status”, and changed the filing date of the divisional application from the filing date of the parent to the date the divisional application was submitted to the Canadian Patent Office and then cited the parent as prior art.  Is this the start of a new practice for the Canadian Patent Office?  In addition, Section 30 of the Patent Rules clearly sets forth the steps that an Examiner must follow when examining an application.  There is nothing in this section or other sections of the Patent Act or Rules that provides clear authority to “deny divisional status” and change the filing date.  Accordingly, it also begs the question: “Does the Canadian Patent Office have the authority to do this under the Canadian Patent Act or Rules?”.

Regardless of whether this is a change in Canadian Patent Office practice or a onetime occurrence, this case clearly illustrates that care must be taken when filing voluntary divisional applications in Canada.  As such, we strongly recommend consulting with your Canadian Patent Agent prior to considering filing any voluntary divisional applications.