Process steps an essential limitation in YASMIN product-by-process claims

On May 29, 2013, Justice O’Reilly of the Federal Court of Canada, released his Reasons for Judgment in a prohibition application between Bayer and Cobalt in Canadian Patent No. 2,261,137 listed against Bayer’s YASMIN combination contraceptive.

The 137 Patent, entitled “Process for Producing Drospirenone” relates to a process for producing drospirenone and two synthetic intermediates using ruthenium salts.  Cobalt had alleged, among other things, non-infringement on the basis that the process it uses to make drospirenone was different from that described in the 137 Patent and would not use any ruthenium salt as an oxidizing agent.


Claim 13 of the 137 Patent, the only claim in issue, provides:

13. A product prepared according to the process of claim 12, wherein the product comprises drospirenone and less than 0.2% contaminants from the isolactone

and the 6,7-ring opening product that is produced by acidic attack on the 6,7-methylene group.
Justice O’Reilly rejected Bayers construction that Claim 13 is directed to a compound per se and should be read as if the words “product prepared according to the process of Claims 12” were not there. Justice O’Reillly distinguished the decision of the Supreme Court of Canada in Hoffmann-LaRoche & Co v. Commissioner of Patents, holding:

[16] I disagree with Bayer’s legal arguments. In particular, I do not read in Hoffman-LaRoche a requirement to construe product-by-process claims in the manner Bayer puts forward. In my view, product-by-process claims should not always be read without reference to the specified process. Therefore, Bayer’s Claim 13 must be construed as including the patented process.

[22] Therefore, as a matter of law, I cannot accept Bayer’s assertion that Claim 13 should be construed as if the words “[a] product prepared according to the process of claim 12” did not exist.

In the alternative, Bayer submitted that if the process of Claim 12 is properly read into Claim 13, the latter claim is not limited to a process employing ruthenium salts. According to Bayer, other non-chromium metals may be used in the key oxidation step. Justice O’Reilly rejected this construction noting that the only compound mentioned as being suitable candidates for the key oxidation step were ruthenium salts. Justice O’Reilly held that a single passage in the disclosure suggesting that other catalytic metals may be used cannot expand the breadth of the patent’s invention where the clear language of the claims limits the scope of the invention to processes employing ruthenium salts.

Allegation of Non-Infringement

Justice O’Reilly confirmed that the persuasive burden in proceeding under the PM(NOC) Regulations lies on the Applicants and that a recent decision suggesting the contrary appears to be a typographical error. Once the generic (or in the parlance of the Regulations, the second person)  has presented sufficient evidence to give the allegations in the NOA an air of reality, the burden falls on the brand company (or in the parlance of the Regulations the first person) to demonstrate that the allegation is unjustified.

Based on his construction, Justice O’Reiily held that Bayer had failed to meet the burden of establishing that Cobalt’s allegation of non-infringement were not justified and accordingly dismissed the prohibition application.  Having dismissed the application on non-infringement grounds, Justice O’Reilly held it was unnecessary to consider Cobalt’s allegations of invalidity.

A copy of Justice O’Reilly’s Reasons for Judgment may be found here.