Federal Court Allows Addition of Third Inventor to Two Patents

Federal Court Allows Addition of Third Inventor to Two Patents

Photograph of two inventors wearing lab coats in a scientific laboratory. The nearest inventor is looking into a microscope. There are beakers on the counter beside her.

Alexion Pharmaceuticals, Inc. v. Canada (Attorney General), 2023 FC 115

On January 24, 2023, the Federal Court (“the Court”) granted an application pursuant to section 52 of the Patent Act, seeking to add a third person as a named inventor to two patents. The Court found that the omission was a result of inadvertence, rather than delay, and allowed the correction.


In most patent applications, the named inventor is almost never the applicant or owner which makes it easy to overlook and make a mistake. A correction can be made relatively easily before a patent has been issued, pursuant to section 106 of the Patent Rules.[1]

Once a patent issues, the process becomes more costly and time-consuming.

Under section 52 of the Patent Act,[2] only the Federal Court has jurisdiction to amend records relating to title of an issued patent, so a court order is required to amend the inventorship information. In order to receive an order, the applicant typically must submit affidavit evidence in support of their request. Please see our recent reporting of Inguran LLC dba STgenetics v. Commissioner of Patents, and Lundbeck A/S v. Canada (Commissioner of Patents) to learn more about section 52.

In the present decision, Alexion Pharmaceuticals brought an application pursuant to section 52 of the Patent Act, seeking to add Dr. Mark Evans (“Dr. Evans”) as an inventor to both Canadian Patent No. 2,645,810 (the ‘810 Patent) and Patent No. 3,022,097 (the ‘097 Patent). The ‘810 Patent was issued from a Patent Cooperation Treaty Application (“PCT Application”) in 2018, while the ‘097 Patent was a divisional of the ‘810 Patent issued in 2020. Dr. Evans was not included in the list of named inventors (consisting of Dr. Leonard Bell and Dr. Russell Rother) in the PCT application, and was correspondingly excluded from the named inventors of the ‘810 and ‘097 Patent.


Section 52 grants the Federal Court the power to vary an entry in the records of the Patent Office related to title, which has been interpreted broadly to include matter such as inventorship. While section 52 does not specify a test to apply, the Court in this case saw fit to apply the principles from section 31(4) of the Patent Act, which governs the joining of applicants in pending patent applications. According to this subsection, the Court must be satisfied that:

  • The proposed individual(s) should be joined as an inventor; and
  • The omission of the inventor was due to inadvertence or mistake, and not for purpose of delay.

Alexion claimed that it had become aware of Dr. Evans’ contribution to the claimed subject matter and inadvertent omission from the PCT application back in 2016, and subsequently amended three U.S. Patents that were also applied for from the PCT application. As evidence, Alexion included affidavits from Dr. Evans, Dr. Bell, Dr. Rother, and Tara Rahemba, Head of Intellectual Property at Alexion.

Both the ‘810 and the ‘097 Patent were similarly titled “Treatment of Paroxysmal Nocturnal Hemoglobinuria Patients by an Inhibitor of Complement”. The ‘810 Patent claimed “[a]n antibody that binds C5 comprising a heavy chain consisting of SEQ ID NO:2 and a light chain consisting of SEQ ID NO:4”, while the ‘097 Patent claimed the use of that antibody to improve at least one aspect of the quality of life of a patient suffering from paroxysmal nocturnal hemoglobinuria (PNH).

Alexion provided further evidence demonstrating that Dr. Evans made the following contributions:

  1. Evans worked on antibody that binds C5;
  2. Evans was involved in conceiving that the antibody includes a heavy chain consisting of SEQ ID NO:2 and a light chain consisting of SEQ ID NO:4 (sequences defined in ‘810 and ‘097 Patent);
  3. Evans was responsible for sequencing of the antibody having SEQ ID NO:2 and SEQ NO:4 (sequences defined in the ‘810 and ‘097 patents).

Based on the evidence, the Court was ultimately satisfied that Dr. Evans had contributed to the specific claims of the ‘810 and ‘097 Patent, and should be joined as a named inventor of the Patents.


While this case was relatively straightforward, it serves as an important reminder to accurately record the name of the inventor(s) when filing a patent application. Failure to do so may require an expensive court procedure, and can possibly  lead infringers to claim that a false material allegation was made in order to delay or mislead, potentially invalidating one’s patent. For more information on inventorship or amending a patent application, please contact a patent professional at PCK Intellectual Property.


[1] SOR/2019-251.

[2] R.S.C., 1985, c. P-4.

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The contents of this article are provided for general information purposes only and do not constitute legal or other professional advice of any kind.