Federal court confirms requirement of patent specificity for listing patents on the patent register

July 20, 2010

Purdue Pharma v. The Minister of Health, 2010 FC 738

Purdue Pharma sought judicial review of a decision of the Office of Patented Medicines and Liaison (OPML) in which the OPML determined that one of Purdue’s patents (the 738 Patent) was not eligible for listing on the Patent Register maintained in accordance with the Patented Medicines (Notice of Compliance) Regulations (Regulations) in respect of the drug TARGIN.  TARGIN is a controlled-release drug in tablet form that contains two medicinal ingredients: oxycodone hydrochloride (a painkiller), and naloxone hydrochloride, which counteracts certain side effects of oxycodone.  The 738 Patent contemplates a controlled-release technology for delivering oxycodone, and contains 28 claims, none of which mention naloxone.  Claim 5 was particularly at issue, and claims, “A solid controlled release oral dosage form, comprising oxycodone or a salt thereof … an effective amount of a controlled release matrix … and … a suitable amount of a suitable pharmaceutical diluent …”

Purdue claimed that the OPML erred by misinterpreting paragraph 4(2)(c) of the Regulations, which provides that, “A patent on a patent list in relation to a new drug submission is eligible to be added to the register if the patent contains … a claim for the dosage form and the dosage form has been approved through the issuance of a notice of compliance in respect of the submission.”  The phrase “claim for the dosage form” is defined at section 2 of the Regulations as meaning “a claim for a delivery system for administering a medicinal ingredient in a drug or a formulation of a drug that includes within its scope that medicinal ingredient or formulation.”  Purdue asserted that the word “comprising” in claim 5 of the 738 Patent contemplated that medicinal and non-medicinal ingredients not specifically mentioned could be included within the scope of that claim.  In particular, Purdue submitted that a product containing all the ingredients in the dosage form as described in claim 5, along with one or more other active ingredients, would still be included within the scope of claim 5 for the purposes of section 4(2)(c) of the Regulations, so long as one of those active ingredients was oxycodone or a salt thereof.

Justice Crampton disagreed with Purdue’s position, however, and found that the OPML correctly determined that the dosage form contemplated by claim 5 of the 738 Patent related to a formulation containing oxycodone as the sole medicinal ingredient, and that naloxone was therefore not within the scope of the claim for the purposes of the Regulations.  A construction of claim 5 that would include within its scope a potentially unlimited number of other unnamed medicinal ingredients would be inconsistent with the objective of product specificity that was enshrined in section 4 of the Regulations by the 2006 amendments thereto.  As a consequence, where a patent relates to a delivery system for administering medicinal ingredient(s) in a drug or formulation of a drug, in order to be eligible for listing on the Patent Register against an approved combination drug, the patent must contain a claim that includes within its scope each of the medicinal ingredients  contained in the approved combination.  Here, because naloxone did not fall within the scope of claim 5, the 738 Patent was not eligible to be listed on the patent register against the combination drug product TARGIN. 

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