On March 8, 2019, the Federal Court issued a prohibition order against a generic version of GLUMETZA® (metformin hydrochloride extended-release tablets) proposed by Generic Partners Canada Inc. (Generic Partners) in an application under the pre-CETA Patented Medicines (Notice of Compliance) Regulations. GLUMETZA® is marketed in Canada by Valeant Canada LP/Valeant Canada SEC (Valeant), which asserted Canadian Patent No. 2,412,671 (671 Patent) against Generic Partners in the proceeding.

671 Patent and its Claims

The 671 Patent relates to oral water-swellable oral dosage forms for drugs (e.g., metformin) that may benefit from a prolonged period of controlled release in the stomach and upper gastrointestinal tract. In particular, the 671 Patent specifies particular shapes and sizes of dosage form that are said to reduce or eliminate the proportion of dosage forms that escape from the stomach through the pylorus, while remaining easily swallowed.

Justice Fothergill accepted Valeant's construction of Claim 1 of the 671 Patent. Claim 1 is to a controlled-release, gastric-retentive oral dosage form with the parameters of three essential features specified: a Size Element, a Time Element, and a Shape Element. It was unnecessary to construe any of the other claims in order to dispose of the application.

Allegations of invalidity not justified

  • Anticipation/Gillette Defence. Generic Partners alleged that the 671 Patent was anticipated by PCT Patent Application WO 98/55107 (WO 107). WO 107 also discloses swellable dosage forms that enhance gastric retention, shares a common inventor with the 671 Patent, and is cited in the description of the 671 Patent. The Court found that while the Size and Time Elements claimed in the 671 Patent were arguably disclosed implicitly by WO 107 in the light of the common general knowledge, the Shape Element could not be ascertained by reading WO 107. Therefore, Claim 1 of the 671 Patent was not anticipated and the Gillette Defence must fail.
  • Obviousness. The Court also rejected the obviousness allegations against the 671 Patent, finding that while the Size and Time Elements may have been disclosed by the prior art (which included WO 107), the Shape Element and the combination of all three elements were not. Without the insight that dosage shapes would affect gastric retention, the invention could not have been obvious to try.
  • Double-patenting. Generic Partners alleged double-patenting over Canadian Patent No. 2,290,624 (the 624 Patent), the basis for which was WO 107. The Court relied on its anticipation and obviousness findings about WO 107/the 624 Patent to reject the double-patenting allegation against the 671 Patent.
  • Insufficiency. Generic Partners challenged the 671 Patent on the basis that it does not provide sufficient information to allow the skilled person to know, in advance of testing, if the formulations disclosed will actually enhance gastric retention. The Court accepted Valeant's evidence that dosage forms falling within the claims could be made using standard dies and punches, and that any additional testing required would be routine or trivial. Although the expert put forward by Generic Partners alleged that the 671 Patent lacked data and examples, the Court found rejected this attack on the bases that it is not necessary for an inventor to provide a theory of why the invention works and no allegation of inutility had been made.

Link to decision: Valeant Canada LP/Valeant Canada SEC v. Generic Partners Canada Inc. et al., 2019 FC 253

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