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Federal Court Determines Admissibility of Testimony from Fact Witnesses who Authored Prior Art

In Medexus Pharmaceuticals v Accord Healthcare (2024 FC 424), Justice Pallotta dismissed the plaintiffs’ (“Medexus”) patent infringement action after finding that the patent at issue (“662 Patent”) was invalid for obviousness. The 662 Patent related to concentrations of subcutaneously injected methotrexate solutions used to treat rheumatoid arthritis and psoriasis/psoriatic arthritis.

The decision addresses an interesting issue on the admissibility of testimony from fact witnesses who were authors of a prior art reference relied upon by the defendants.

Medexus Pharmaceuticals Inc v Accord Healthcare Inc, 2024 FC 424

At trial, Medexus called three fact witnesses. Two of these witnesses, Drs. Jansen and Janssen (the “Witnesses”), were authors of a prior art reference that the defendants (“Accord”) relied on. Accord quickly moved to exclude the Witnesses’ testimony on the basis that it was irrelevant, improper, and prejudicial because it was expert opinion rather than fact evidence.

Specifically, Accord argued that the Witnesses’ testimony was irrelevant because the Witnesses were going to testify about their personal knowledge and experience with methotrexate. Obviousness is based on an objective assessment based on expert evidence of the skilled person’s perspective and assessment of the prior art.

Accord also argued that the Witnesses’ testimony would be improper and prejudicial because it amounted to expert evidence and had not satisfied the usual requirements of opinion evidence. Justice Pallotta dismissed Accord’s motion, reserving her decision on admissibility until she had heard the Witnesses’ testimony in full. Once she heard the testimony, she held it was inadmissible.

The Witnesses’ testimony related to three topics:

  1. the prior art reference relied on by Accord (“Jansen 1999”);
  2. aspects of the state of the art; and
  3. whether the Witnesses considered increasing the concentration of methotrexate solutions or creating a new methotrexate formulation.

On the first topic, the Witnesses testified about what they wrote in Jansen 1999 and sometimes strayed into explaining the meaning of certain parts of the article. However, the Court held that no issue turned on the admissibility of the Witnesses’ evidence about Jansen 1999 because their testimony was not materially different from the plain meaning of the article and the expert witnesses’ opinions.

On the second topic, the Witnesses testified about:

  1. the dosage forms and concentrations of methotrexate that were used as of the claim date;
  2. their knowledge and their colleagues’ knowledge in the relevant period; and
  3. whether patients with rheumatoid arthritis would experience injection pain with subcutaneously administered methotrexate.

The Court held that this part of the testimony was inadmissible as improper expert opinion because the Witnesses:

  1. were not instructed on the proper framework for providing expert evidence;
  2. did not opine from the skilled person’s perspective in light of applicable legal principles;
  3. did not clearly favour or contradict any expert’s opinion; and
  4. did not assist the Court in resolving any contentious points about the state of the art or the common general knowledge.

For similar reasons, the Witnesses’ evidence on the third topic was also inadmissible. For the third topic, Justice Pallotta noted that “while the actions of an ‘actual person’ of ordinary skill can be relevant to an obviousness analysis, the evidence of [the Witnesses] is not relevant or helpful to the obviousness inquiry in this case.” The Witnesses had simply answered “no” to a series of questions relating to whether certain activities occurred in the relevant period. The Witnesses provided no further explanation or context to assist the Court resolve the issues in dispute.

Justice Pallotta’s decision serves as a reminder of the purpose and procedural safeguards that separate expert evidence from fact witness testimony.