Canada: Pharma In Brief - Federal Court Applies Restrained Approach To Promise Of The Patent And Holds That Methods Of Medical Treatment Are Not Patentable

Case: Bayer Inc v Cobalt Pharmaceuticals Company, 2013 FC 1061

Drug: YAZ® (drospirenone/ethinyl estradiol)

Nature of case: Prohibition proceedings under the Patented Medicines (Notice of Compliance) Regulations

Successful party: Divided

Date of decision: 22 October 2013


This case concerns a proposed generic version of the birth control combination drug YAZ® (drospirenone/ethinyl estradiol). Bayer Inc. and Bayer Pharma Aktiengesellschaft (Bayer) sought an order prohibiting the Minister of Health from issuing a notice of compliance in respect of the proposed generic, developed by Cobalt Pharmaceuticals Company (Cobalt), under section 6 of the Patented Medicines (Notice of Compliance) Regulations, SOR/93-133.

Bayer relied on Canadian Patents No. 2,382,426 (the '426 Patent) and 2,179,728 (the '728 Patent). Cobalt alleged that the former was invalid for obviousness, inutility, overbreadth, insufficiency, and ambiguity, and that the latter was invalid for obviousness, double-patenting, inutility, and claiming non-patentable subject matter. It further alleged non-infringement in respect of both patents. Justice Hughes agreed with Bayer that Cobalt's allegations regarding the '426 Patent were not justified and issued a prohibition order on that basis. However, Bayer failed to show that Cobalt's non-infringement and non-patentable subject-matter arguments were not justified with respect to the '728 Patent.

This decision is notable for its strong endorsement of a more restrained approach to construction of a patent's promised utility and its analysis of "methods of medical treatment" as a ground of invalidity.

The issues

The '426 Patent concerns oral contraceptive compositions containing drospirenone and ethinyl estradiol, delivered in a form that achieves good oral bioavailability through rapid dissolution, including by micronization of the medicinal ingredient or spraying onto an inert carrier.

The '728 Patent, meanwhile, claims the use of a pharmaceutical composition for oral administration comprising either ethinyl estradiol or 17β-estradiol and a second medicinal ingredient selected from a group of compounds, including drospirenone, for female contraception according to a defined schedule of administration


With respect to the '426 Patent, the issue of non-infringement turned on the construction of a claim to an oral dosage form of drospirenone and ethinyl estradiol defined by its fast rate of dissolution. Having regard to the specification as a whole, Hughes J held that the claim was broad enough to include the Cobalt formulation provided its dissolution time was within the claims of the patent. Because Cobalt provided neither samples of its tablet nor information regarding the tablet's dissolution profile, Hughes J held that its allegation of non-infringement was not justified.

Cobalt also alleged non-infringement of the '728 Patent on the basis that its proposed generic contained more drospirenone than the claimed formulations. In the relevant claims, the quantity of drospirenone is expressed as a range, the upper boundary of which is in each case expressed as the "dose equivalent" of a defined quantity of gestodene (another hormonal contraceptive). Justice Hughes held that neither the patent nor the prior art defined with certainty what the "dose equivalent" would be, and that to the extent such direction could be taken from the prior art, the quantity would most likely be 2 mg. There was no need to come to a settled conclusion because Cobalt's product contained 3 mg of drospirenone and was, in either case, outside the ambit of the claims.


The obviousness analysis was straightforward with respect to both patents in this case. Concerning the '426 Patent, Hughes J agreed with Bayer's expert evidence that the prior art taught away from rapidly-dissolving oral dosage forms of drospirenone without enteric coating. He also held that the prior art cited with respect to the '728 Patent did not disclose drospirenone. Of note, Cobalt unsuccessfully attempted to lead evidence of the "history of the invention" in support of its obviousness allegations regarding the '426 Patent. Justice Hughes found this evidence to be unpersuasive, both because of the piecemeal fashion in which it was assembled and because it was contradicted by Bayer's own evidence from some of the same scientists upon whose work Cobalt relied.


Cobalt's arguments on the utility of the '426 Patent focussed on (1) an allegation that Bayer used a non-micronized form of drospirenone in its testing and (2) a broad construction of the promised utility of the invention. With respect to the first prong, Hughes J agreed with Bayer's uncontradicted evidence that micronized drospirenone was, in fact, tested.

The Court's reasons regarding the "promise" of the '426 Patent are consistent with the more moderate approach described in Sanofi-Aventis v Apotex Inc, 2013 FCA 186. Following that case, Hughes J observed that not all patents contain a promised utility, and that not all statements of advantage rise to the level of a promise. Applying that latter dictum, he concluded that the '426 Patent promised good oral bioavailability resulting from rapid dissolution. This much was demonstrated. By contrast, he held that a statement of the inventors' theory as to the mechanism by which that result is made possible is not a further promise. As such, he agreed that Bayer was not required to demonstrate or soundly predict a correlation between in vitro dissolution and in vivo oral bioavailability, as Cobalt alleged.

Notably, Hughes J did not allow Cobalt to raise inutility arguments that were not present in its notice of allegation through the evidence of one of its experts.

Hughes J also agreed that Cobalt's allegations of inutility with respect to the '728 Patent were not justified, but without any substantial reasons.


Cobalt alleged that the '728 Patent was invalid for double-patenting in light of two other patents owned by Bayer. Curiously, one of these patents was the '426 Patent, the application for which post-dates that of the '728 Patent by over five years. As Hughes J observed, while the earlier-filed '728 Patent might have served as a basis to challenge the validity of the later-filed '426 Patent, the reverse could not be true. The Court also preferred evidence to the effect that the second patent in issue was clearly distinct from the '728 Patent.

Method of medical treatment: Not patentable subject-matter

This is the second recent decision to consider the non-statutory "rule" that methods of medical treatment are not patentable subject-matter. Relying on his own recent analysis in Novartis Pharmaceuticals Canada Inc v Cobalt Pharmaceuticals Company, 2013 FC 985, Hughes J held that four of the five claims in issue were invalid on this ground because, rather than a vendible product, they each claimed a range of components and dosages from which a particular combination must be selected. Only one of the claims in issue, directed at a specific dose of each constituent drug in the combination, survived.

Overbreadth, insufficiency, and ambiguity

Cobalt also argued overbreadth and insufficiency of the '426 Patent. Justice Hughes resolved these issues in favour of Bayer based on his construction of the patent. He also addressed the argument that use of the term "about" preceding measurements rendered the '426 Patent invalid for ambiguity. Justice Hughes held that the USP provided a precise definition for this term with the result that it was not a source of ambiguity.

Link to decision:

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