2018-01-16
Double patenting is the granting of two patents for a single invention to the same applicant. It occurs when the same invention is claimed in more than one patent owned by the same entity. Most patent systems across the world work on the principle that two patents cannot be granted to a single invention, belonging to the same person or an entity. As a result, most jurisdictions prohibit double patenting, including Canada. However, double patenting doctrines vary from jurisdiction to jurisdiction. There are certain unique aspects to double patenting in Canada that may influence your patent strategies.
Double Patenting in Canada
As mentioned above, double patenting is prohibited in Canada. In Whirlpool Corp v. Camco In., 2000 SCC 67, the Supreme Court held that an inventor is only entitled to one patent of each invention, and also stated that a patentee who claims successive patents for a single invention by way of obvious variations extends the scope of the patent term. In the Canadian jurisprudence, the prohibition against double patenting has two branches:
- ‘Same Invention’ branch, where one or more claim of the second patent is identical or coterminous to those of the first patent. This branch will invalidate any claim of the pending or issued second patent that is similar to that of an earlier issued patent.
- ‘Obviousness-type’ branch, where one or more claim of the second patent is obvious or not patentably distinct from those of the previously issued patent. This branch invalidates any claim of the pending or issued second patent that is non-inventive or obvious from any claim in the earlier issued patent.
Both these branches of double patenting can prove to be fatal for Canadian applicants. However, sometimes in Canada, the subject matter of the second application may qualify as a selection invention. A selection invention includes claims related to a compound or a sub-class compound that is distinct from the broader genus in the earlier issued patent. As highlighted in Sanofi-Synthelabo Canada Inc. v. Apotex Inc., such selection patents will not be invalidated on the basis of obviousness. Canadian patent law also permits the filing of voluntary divisional applications.
However, care must be taken to ensure that the claims in the divisional application are patentably distinct from those of the earlier patent. If the Patent Office forced the filing of a divisional patent, it becomes immune from double patenting and and cannot be invalidated on those grounds. It is common practice in many jurisdictions to voluntarily cancel claims in the parent application to secure the first patent, and then file a divisional application to pursue those canceled claims. However, such a strategy is not recommended in Canada because a double patenting risk may also rise against claims in the voluntarily filed divisional applications.
Risks of Double Patenting
An ‘obviousness-type’ double patenting risk has a high chance of occurrence if any claim in one application arguably fails to show any novel aspect in comparison with the earlier issued patent. Whether the second patent expires on the same day as the first, it may be held invalid for double patenting, mainly because the existence of a second patent may confer advantages to the patentee. It must also be noted that, unlike the U.S., where there is a terminal disclaimer provision to obviate the ‘obviousness-type’ double patenting, Canada has no such provision.
Applicants tend to file multiple applications for related subject matter. With the risk of double patenting, a better approach in Canada is to consolidate multiple claims into a single application and file divisional applications when an election of claims is required by the patent office. Before seeking patent protection in Canada, you should consider these aspects of double patenting to avoid rejection. A patent agent’s guidance can help you successfully obtain a patent.
