Summary – Bayer attempted to broaden the scope of a product-by-process claim by arguing that the process recited in the claim was a non-essential feature and should not be considered as part of the claim. The Court disagreed and found the process steps essential and not infringed by Cobalt, who wished to produce the same product through a different method of manufacture.
Analysis – Bayer holds Canadian Patent No. 2,261,137, directed to processes for producing drospirenone (an oral contraceptive marketed as YasminTM) and drospirenone produced according to these processes. As this was a decision under the Patented Medicines (Notice of Compliance) (PM(NOC)) Regulations, the process claims were not eligible to be asserted. Furthermore, Cobalt indicated that the patented process would not be used. Therefore, only product claim 13 was at issue. Claim 13 is specifically directed to purified drospirenone, claimed in terms of its method of manufacture and is as follows:
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.
The process referred to in claim 13 involves three steps, including ruthenium salts-mediated oxidation. In addition, two named intermediates were recited as being produced prior to final production of drospirenone.
Bayer argued that claim 13 should be interpreted broadly to be directed only to the compound and not to include the recited method steps. Alternatively, Bayer argued that the method steps should not be construed to require ruthenium salts-mediated oxidation as recited but, rather, oxidation by any appropriate metal salt. These arguments were not well-grounded in either law or fact and, not surprisingly, the Court disagreed with Bayer’s interpretation. It was found that the method steps and the use of ruthenium salts-mediated oxidation, both features that were explicitly recited in the claims, were essential elements of the claimed invention.
Once the question of claim construction was decided, the question of infringement was a simple one to deal with. Cobalt stated that they would not infringe this claim because they would produce drospirenone by another method, which did not use ruthenium salts-mediated oxidation and did not result in production of the two intermediates that were recited in the claims. The Court agreed and found that Cobalt did not infringe the claim at issue. Accordingly, the validity of claim 13 was not addressed.
Practice Point – Product-by-process claims are claims directed to a product that is limited in terms of its method of manufacture. In order for a product-by-process claim to be patentable, the product itself must be both novel and inventive, irrespective of the recited process steps. Therefore, in most cases, it is possible to define the novel product independently of its method of manufacture (for example, in terms of a specific purity level unobtainable in the past). It is good practice to include claims to the product itself, defined in terms of features that are not process-limited, whenever possible so as to avoid non-infringement by modifying a process step.