Canada - Prior Use as a Ground of Patent Invalidity

Newsletters and Bulletins / August 2002 / Canada

One of the consequences of the major changes in Canadian patent law that took place in 1989 and 1996 was that a European-style definition of novelty was adopted as opposed to the old definition that had more similarities to U.S. law. As a result, the old bar on the patenting of something that had been "in public use or on sale in Canada for more than two years prior to ... filing" was replaced by a bar on patenting anything that had been disclosed in such manner that the subject matter became available to the public in Canada or elsewhere. Disclosures by or deriving from the applicant are given a one-year grace period before they become effective as bars, but all other disclosures have immediate effect.

The significance of this change was considered for the first time by the Federal Court of Appeal in Canwell Enviro-Industries Ltd. v. Baker Petrolite Corp. The patent in question claimed a method of reducing certain pollutants from a gas stream by treating it with a composition that was defined as being the product of a particular chemical reaction. One of the issues in the case was whether commercial sale of a particular composition before the relevant date was a bar to the claims in suit. The purpose for which the composition was sold was the same as that of the patent. The court reviewed the relevant British and European Patent Office decisions on what constituted prior use under statutes having similar wording to the new Canadian law and set out the following principles which it derived from that review.

1. Sale to the public or use by the public alone is insufficient to prove anticipation.

2. For a prior sale or use to anticipate an invention, it must amount to an "enabling disclosure."

3. The prior sale or use of a chemical product will constitute enabling disclosure to the public if its composition can be discovered through analysis of the product.

4. The analysis must be able to be performed by a person skilled in the art in accordance with known analytical techniques at the relevant time.

5. In the context of patent anticipation under the Canadian statute, when reverse engineering is necessary and capable of discovering the invention, an invention becomes available to the public if a product containing the invention is sold to any member of the public who is free to use it as he or she pleases.

6. It is not necessary to demonstrate that a member of the public actually analyzed the product that was sold.

7. The amount of time and work involved in concluding the analysis is not determinative of whether a skilled person could discover the invention.

8. It is not necessary that the product that is the subject of analysis is capable of exact reproduction. It is sufficient that the analysis shows that the product in question was an embodiment falling within the claim in suit.

Based on these points, the court concluded that what had been sold before the relevant date was capable of having been analyzed to show that it fell within the scope of the patent claims and therefore constituted an anticipation of the claims in suit.

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