Case: Apotex Inc. v. Allergan Inc. 

Drug: brimonidine-timolol (COMBIGAN®)

Nature of case: Prohibition proceeding pursuant to Section 6 of the PM(NOC) Regulations  

Date of decision: November 23, 2012


On November 23, 2012, the Federal Court of Appeal upheld a prohibition order preventing the Minister of Health from issuing a Notice of Compliance to Apotex Inc. (“Apotex”) in respect of its generic form of COMBIGAN® until the expiry of Allergan Inc.’s (“Allergan’s) Canadian Patent No. 2,440,764 (the “’764 Patent”).

The Court of Appeal held that Apotex’s allegations of obviousness were not justified and that the Federal Court had erred in its interpretation of the “inventive concept” of the relevant claims. The Court also provided guidance on the principle of comity and how it should be applied in the context of cases brought pursuant to the Patented Medicines (Notice of Compliance) Regulations (the “PM(NOC) Regulations”).


The ‘764 Patent is directed to a combination product used for the reduction of intraocular pressure, a major risk factor in glaucoma. Brimonidine and timolol, the two products in the claimed combination, were previously known to treat intraocular pressure. The inventors of the ‘764 Patent discovered that when these medicines are combined in particular ratios, the claimed combination produces a better safety profile than the compounds taken individually.

Prior Proceedings

In a prior proceeding pursuant to the PM(NOC) Regulations, another generic drug manufacturer challenged the ‘764 Patent on the basis that the claimed combination was obvious in light of the prior art. In that case, Justice Crampton held that on a reading of the patent as a whole, the inventive concept included the improved safety profile. Justice Crampton applied this construction and held that the invention was not obvious.

Decision under appeal

In the present case, the Federal Court judge read the patent differently than Justice Crampton. The Federal Court judge focused on a particular paragraph from the ‘764 Patent and held that the inventive concept underlying the relevant claims did not include the improved safety profile. The Federal Court judge went on to hold that the invention was obvious.

The Federal Court judge was troubled by the issue of comity as his own conclusions differed from those of Justice Crampton. In reviewing the relevant jurisprudence, the Federal Court judge identified what he believed to be conflicting case law from the Court of Appeal in the application of comity and re-litigation in PM(NOC) proceedings. Knowing that if he followed his own conclusions and refused to award the prohibition order the Court of Appeal would be unlikely to hear the case, the Federal Court judge awarded the prohibition order.

Decision of the Federal Court of Appeal 

The Court of Appeal held that the parties were entitled to have their dispute decided on the merits and that the Federal Court judge erred in issuing a formal judgment that was contrary to the conclusions he reached. 


On the issue of comity, the Court of Appeal held that conclusions of law of a Federal Court judge should not be departed from by another judge unless he or she is convinced that the departure is necessary and can articulate cogent reasons for doing so. In contrast, the Court of Appeal stated that the doctrine of comity has no application with respect to findings of fact.

In applying this principle to the case at bar, the Court of Appeal held that construction of a patent or a patent claim, including construction of the inventive concept of a claim, is a question of law. Therefore, the Court of Appeal held that unless the Federal Court judge could demonstrate that Justice Crampton’s construction was wrong, or that distinct evidence adduced before him compelled him to reach a different conclusion, it would have been preferable for him to adhere to Justice Crampton’s construction.

The Court held that the Federal Court judge did not identify any error on the part of Justice Crampton, nor did he rely on distinct evidence to explain his divergent view. He simply chose to construe the patent differently. The Court of Appeal held that none of the reasons mentioned by the Federal Court judge justified coming to a different construction.

Inventive Concept

While the Federal Court judge ought to have adhered to Justice Crampton’s construction, his independent analysis left two conflicting and equally authoritative constructions of the ‘764 Patent and the Court of Appeal took on the task of determining which was the correct one.

The Court of Appeal found that the Federal Court judge erred by limiting the inventive concept of the relevant claims to the features discussed in a single paragraph of the specification. The Court of Appeal held that this narrow approach was contrary to the principle that the inventive concept must be construed in light of the patent as a whole. In the Court’s view, a purposive and complete reading of the ‘764 Patent led to the conclusion that the improved safety profile did form part of the inventive concept of the claim in question. 


In light of the error at the “inventive concept” stage of the obviousness inquiry, the Court of Appeal held that the remainder of the Federal Court judge’s obviousness analysis could not stand. However, the Court of Appeal held that it would be more efficient for it to decide the issue of obviousness on the merits rather than send the case back to the Federal Court for determination.

On the merits, the Court of Appeal rejected each of Apotex’s arguments of obviousness. The Court noted that, if anything, prior experience combining the two drugs at issue taught away from the invention.

Finally, the Court of Appeal pointed to the extensive clinical trial work that established the advantageous safety profile of the claimed combination. The Court of Appeal noted that the trial was not conducted with the expectation that the combination would reveal the improved safety profile and therefore was evidence that the invention was not obvious to try.  The Court of Appeal concluded that Apotex’s allegation of obviousness was not justified.


The Court of Appeal held that the prohibition order was properly granted by the Federal Court, but for the wrong reason. Since Allergan was entitled to a prohibition order on the basis that the allegation of obviousness was not justified, the Federal Court of Appeal dismissed the appeal.

Links to decision:

Apotex Inc. v. Allergan Inc., 2012 FC 308