Tobramycin patent listing – Federal Court confirms strict product specificity

On June 29, 2012, the Federal Court issued a decision upholding the Minister of Health‘s decision to refuse to list Canadian Patent No. 2,304,819 against Novartis’ TOBI PODHALER product.

Background

The ‘819 patent, entitled “Perforated Microparticles and Methods of Use”, includes claims directed to a perforated microstructure powder comprising a bioactive agent (claims 41 to 50 and 59 to 68) and claims directed to an inhalation system (claims 51 to 58) .  While the ‘819 patent discloses a number of bioactive agents, including two related antibiotics, the patent does not disclose tobramycin as a potential active agent.  The Minister of Health refused to add the ‘819 patent to the Patent Register on the basis that the ‘819 patent did not specify tobramycin as a potential active agent. Novartis then sought judicial review of the Minister refusal to list the ‘819 patent.

Product Specificity

There was no dispute between the parties that tobramycin is an antibiotic and that certain claims specifically refer to antibiotics as a possible bioactive agent.  The principal issue was the proper interpretation of paragraph 4(2)(b) of the Regulations.  Following the Court’s decision in Bayer (2009 FC 1171, aff’d  2010 FCA 161) and Gilead (2012 FC 2), Justice Martineau  held that the product specificity threshold for the listing of formulation claims under paragraph 4(2)(b) is “rather high” and concluded:

I agree with the applicant that the facts in this case are different with the facts in Bayer, above. Nonetheless, the ratio in Bayer (FC), above, readily applies. Essentially, the applicant is asking the Court to do exactly what the Federal Court of Appeal refused to do in Bayer; that is, to find that the inclusion of antibiotics as a class, without specifying tobramycin, is sufficient to constitute a claim for the formulation containing the medicinal ingredient. This type of inclusion had been rejected in Bayer, and more strictly in Gilead, with regard to the interpretation of paragraph 4(2)(b) of the Regulations.

With respect to dosage form claims sought to be listed under paragraph 4(2)(c), Justice Martineau, following the Court of Appeal in Purdue (2011 FCA 132) , concluded  that the ‘819 patent was ineligible for listing as the delivery system could be used in association with a broad range of medicinal ingredients:

There is no doubt that the approved dosage form of Tobi Podhaler is more complex and more nuanced than an intravenous stand or a syringe. However, the rationale remains the same because the delivery system on the grounds of which the applicant seeks to list the ‘819 patent, including its different components, is one that can be used in association with a broad range of medicinal ingredients and is therefore insufficient to help the ‘819 patent qualify under paragraph 4(2)(c) of the Regulations.

A copy of Justice Martineau’s Reasons for Judgment and Judgment is available from the Federal Court website here.