In Merck & Co. Inc. v. Pharmascience Inc. (2010 FC 510), the Federal Court (FC) dismissed Merck & Co. Inc.’s (Merck) application to prohibit the Minister of Health from issuing a Notice of Compliance (NOC) to Pharmascience Inc. The FC found Canadian Patent No. 2,173,457 (the ’457 patent) invalid on the basis of double patenting and anticipation. Significantly, the FC held that, despite its finding of anticipation, the ’457 Patent was not obvious because prior art subsequent to the anticipating art would have discouraged any inquiry in to the relevant field of research.

Pharmascience had sought a NOC to market a generic version of the medicine finasteride, used in the treatment of male pattern baldness. Only dependent claim 5 of the ’457 Patent remained in issue, and the FC summarized it as follows: “the use of finasteride for the preparation of a medicament adapted for oral administration useful for the treatment of male pattern baldness in a person and wherein the daily dosage is about 1.0mg.”

The FC performed a historical review of the law on claims construction, noting the emergence of claims in patents and the current focus of construction on those claims. The FC then analysed the law pertaining to Swiss-type claims: the use of an old compound in the manufacture of a medicine for the treatment of a new disorder). The FC noted that such claims have been approached in two conflicting ways. First, courts have viewed them as directed to the manufacture of a product. Second, courts have viewed the Swiss structure of the claim, which is drafted in terms of manufacture, as merely secondary to the real intent in claiming a new use. However, the FC declined to decide which approach was appropriate under Canadian law as Pharmascience argued in its Notice of Allegation that Claim 5 of the ’457 Patent was directed to a particular dosage, rather than the manufacture of a tablet, and was therefore bound to its own construction.

Double Patenting

The FC held the ’457 Patent was invalid for double patenting over Canadian Patent No. 1,302,277 (the ’277 patent). The FC summarized the law of double patenting by noting that it is the claims of each patent are compared to determine if they are “identical or co-terminus” or whether the latter patent is obvious in view of the former. The FC then distinguished obviousness double patenting from the obviousness inquiry in that the inquiry in the former is not bothered with whether the earlier patent would have come to the attention of the notional person skilled in the art, does not extend to the validity of the earlier patent and does not extend to prior art beyond the earlier patent. Here, the prior ’277 Patent differed primarily by its lack of constraint on dosage; it simply provided a range of 5mg/day to 2000mg/day, whereas the ’457 Patent provided for an approximate 1mg/day dose. The FC held thus held that Claim 5 of the ’457 Patent was identical or co-terminus with claims of the prior ’277 Patent and was therefore invalid. The ’457 Patent was also invalid for obviousness double patenting because the prior art that Merck argued taught away from the ’457 Patent was not relevant to this inquiry.

Anticipation

The FC also found that the ’277 Patent anticipated the ’457 Patent and therefore the latter was invalid. Although a dosage range was claimed in the ’277 Patent, the FC held that it would be within the skill expected of a person skilled in the art, as acknowledged in the ’457 Patent itself, to determine appropriate dosages for each person. There was no “undue burden” in determining this appropriate dosage despite the existence of prior art suggesting that the dosage set out in the ’457 Patent would not be effective. Therefore, claim 5 of the ’457 Patent was not novel.

Obviousness

Significantly, the FC then held that the very prior art cited for anticipation would teach away from the claimed solution of the patent. This was enough to conclude that the person skilled in the art would put expectations of success respecting the invention described in the ’457 Patent so low that one would never start inquiries in that area. Because a researcher would be discouraged from pursuing research in that area and motivation would be lost, the ’457 Patent was not obvious. In distinguishing novelty and non-obviousness, the FC noted that novelty invokes a consideration as to whether the public is already possessed of what is claimed, regardless of whether it is invented or not, and the fact that any suspicion or discouragement raised by the prior art would have to be dispelled is irrelevant.