The Federal Court (FC) has refused to overturn a decision of the Patented Medicine Prices Review Board (PMPRB or Board) that found that a patent can pertain to a medicine based on “clinical similarities” to the invention—even if the patent does not actually encompass the medicine. The FC concluded that the Board’s decision was reasonable.


This case concerns Canadian Patent No. 2,478,237 (the 237 Patent), which relates to the use of adapalene to treat dermatological disorders. The patentee, Galderma Canada Inc. (Galderma), markets two adapalene products in Canada:

  • Differin®, which contains 0.1% adapalene (DIFFERIN).
  • Differin XPTM, which contains a higher concentration of adapalene: 0.3% (DIFFERIN XP).

There is no dispute that the 237 Patent pertains to DIFFERIN XP. PMPRB took the position that the 237 Patent also pertains to DIFFERIN, and that Galderma had failed to report the required sales and financial information in respect of this product from January 1, 2010 until the 237 Patent expired on March 14, 2016. Galderma argued that the 237 Patent is not intended or capable of being used for DIFFERIN—a 0.1% adapalene formulation—because on its face, the patent is specific to 0.3% adapalene formulations (such as DIFFERIN XP).

As we reported, the Federal Court of Appeal (FCA) overturned the Board’s first decision against Galderma in 2019 and returned the matter to the PMPRB for redetermination on the basis that the invention of the 237 Patent is the use of a 0.3% concentration of adapalene for the treatment of dermatological disorders. The FCA also held that the PMPRB should be allowed to address “what kind of clinical similarities would support a finding that the invention of a patent was intended or capable of being used” for a specific medicine. On redetermination in 2020, the Board concluded that the 237 Patent pertain to clinical similarities between DIFFERIN and DIFFERIN XP (see our summary of that decision here), leading to this second application for judicial review.

Federal Court agrees with “clinical similarities” analysis

The FC held that it was reasonable for the Board to conclude that “Differin and Differin XP are the same medicine, albeit in different concentrations”, referring to the shared product monograph for the two products as support for the conclusion that there is a “rational connection between them”. As summarized by the FC:

The Board found that the invention of the 237 Patent and Differin produced similar clinical effects, with the former acting more rapidly and producing a greater therapeutic effect after eight weeks. The side effects were comparable between the two, although experienced at different rates, and both were well-tolerated. The two medicines were not interchangeable, but they were prescribed for similar conditions and could in some circumstances be substituted for each other.

FC Decision at para 62

The FC rejected Galderma’s argument that the Board’s decision was unreasonable because it failed to assess whether the 237 Patent conferred an ongoing market benefit in relation to DIFFERIN, holding:

(a) While the relationship between a patented invention and an off-patent medicine may be tenuous, the fundamental question is whether the invention is intended or capable of being used for the medicine, not whether there is the merest slender thread of a connection.

(b) Where it appears that a patent confers exclusivity with respect to a portion of the market relating to the medicine being sold in Canada, there is a presumption that its mere existence confers market power by distorting the competitive process and competitors are dissuaded from entering the marketplace. There is no need for Board Staff to demonstrate actual market distortion, and no opportunity for a patentee to prove the contrary.

(c) The Board has neither the mandate, nor the necessary experience and expertise, to go beyond the face of a patent to construe the use claims before determining whether they correspond to the uses stipulated in the NOC for an off-patent medicine. A finding that, on its face, the patent is intended or capable of being used for the off-patent medicine is sufficient to establish the Board’s jurisdiction.

FC Decision at para 57

Different strengths vs. combinations

It is notable that the Board’s original decision also considered whether two patents to adapalene combination products pertained to the adapalene monotherapies, DIFFERIN and DIFFERIN XP. In contrast to its decision regarding different strengths of adapalene formulation, the Board concluded that a simple reference to adapalene in the combination patents is insufficient to establish the necessary rational connection.

Link to decision: Galderma Canada Inc. v Canada (Attorney General), 2024 FC 46.