A Product-by-Process Claim Is Not a Product Claim

Bayer Inc v Cobalt Pharmaceuticals Co / drospirenone (NOC) 2013 FC 573 O'Reilly J
            YASMIN® / drospirenone / 2,261,137

In this application Bayer sought an order of prohibition preventing Cobalt from launching a generic version of YASMIN® until the expiry of the ‘137 patent. O’Reilly J refused to grant the order on the basis on non-infringement, and he did not reach Cobalt’s invalidity arguments. The infringement issue turned entirely on claim construction. Bayer’s claim construction argument were far-fetched, and were dismissed by O’Reilly J without difficulty.

Drospirenone is a old compound. The first 12 claims of the ‘137 patent are claims to a process for the production of drospirenone. The description (p 6) states that “a key reaction” in the process is ruthenium-catalyzed oxidation of certain compounds, and all the process claims incorporate that step. Claim 13, the only claim in issue, was to “A product according to the process of claim 12,” wherein the product comprises drospirenone of specified purity. Cobalt alleged that its product would not infringe because its process for the production of drospirenone would not use a ruthenium salt as an oxidizing agent.

Bayer argued that the use of a ruthenium salt as an oxidizing agent was not an essential element of the claims [30]. O’Reilly J rejected this argument [31]-[36]. While identification of the essential elements can sometimes be difficult, in this case O’Reilly J’s analysis is very straightforward and compelling. All the claims included ruthenium and the description identified its use as “key.” There were no alternatives mentioned apart from chromium, which was mentioned only to be avoided; part of the stated purpose of the invention (p 9) was to avoid the use of chromium, for environmental reasons.

Bayer also argued that the SCC decision in Hoffmann-La Roche [1955] SCR 414 stands for the proposition that product-by-process claims should be read as claims to the product alone [13], so that it does not matter how Cobalt’s product was produced, so long as it was of the required purity. As OReilly J pointed out, what Hoffmann-La Roche really says is that you cannot obtain a new patent for an old compound, even though a new process for making it has been invented [20].

Finally, Bayer argued that a skilled person would read Claim 13 as a claim for the purer form of drospirenone, regardless of how it was made [24]. It is not surprising that O’Reilly J rejected this submission, given that the first words of Claim 13 are “A product according to the process of claim 12.”