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Federal Court Clarifies Duty of Candour Owed During Prosecution of Patent Applications


November 27, 2009


Steven Mason
Anita Nador
Steven Tanner

In a recent Federal Court decision of Lundbeck Canada Inc. v. Ratiopharm Inc., 2009 FC 1102 dated November 23, 2009, Justice Mactavish clarified the duty of candour owed by an applicant pursuant to s. 73(1)(a) of the Patent Act. As summarized by the court, s. 73(1)(a) provides that "an application for a patent shall be deemed to be abandoned if, amongst other things, the applicant does not reply in good faith to any requisition made by an examiner in connection with an examination." [emphasis added]

The court has examined the good faith duty in a number of prior decisions, most recently with regard to the duty to respond to a request by the patent examiner under s. 29 of the Patent Rules regarding the provision of prior art cited in corresponding patent applications or those that describe the same invention. In those cases, the court has taken a hard-line approach, stating that a lack of response to such a request results in automatic abandonment of the application.

In the present case, the court stated that in addition to having a duty to provide the relevant prior art to the patent office in light of such a requisition, the applicant, in replying to a rejection of anticipation or obviousness, must be careful not to mislead the Examiner of the interpretation of prior art. The facts of this particular case are as follows.

Canadian Patent Application No. 2,426,492 was filed in Canada on May 8, 2003 on behalf of its owner, H. Lundbeck A/S ("Lundbeck"). In an office action dated November 12, 2003, the patent examiner stated that the claims were obvious, contrary to s. 28.3 of the Patent Act. The claims were directed to the "synergistic use" of a combination of two previously known compounds in the treatment of mild cognitive impairment or dementia, such as Alzheimer’s disease. The examiner’s rejection noted that the claims were a mere aggregation of the prior compounds and that such claims to a combination of two compounds were invalid unless there was a new and unexpected result. The examiner further stated that there was "no evidence" of a synergistic effect.

In addition to the obviousness rejection, the examiner requested that the applicant provide "an identification of any prior art cited in respect of the United States and European Patent Office application." Although there was no corresponding patent application in either jurisdiction, the applicant identified two documents cited in an International Search Report. One of them was an article by Gary L. Wenk et al ("Wenk").

In response to the office action, Lundbeck stated that there are numerous articles that warn against and teach away from the combination of the two compounds that were the subject of the claims. Therefore, they argued, the combination would have been "counter-intuitive."

The Wenk article, previously provided to the examiner, suggested that the warnings against combining the compounds was limited to a subset of the class of compounds. Lundbeck did not specifically refer to the Wenk article in its response to the obviousness rejection in the office action, and neither did the examiner. The '492 Patent subsequently issued and listed on the Health Canada Patent Register pursuant to the Patented Medicines (Notice of Compliance) Regulations (the "PM(NOC) Regulations"). The Lundbeck case arose from an application launched by Lundbeck pursuant to the PM(NOC) Regulations to prevent the Minister of Health from issuing a NOC (i.e., granting market approval) to Ratiopharm until the expiry of the patent. At the hearing, Ratiopharm argued that the '492 Patent Application was deemed to be abandoned because the applicant had breached its duty of good faith in failing to alert the examiner to the importance of the Wenk article.

Justice Mactavish held that not only did the applicant owe a duty of candour pursuant to s. 73(1)(a) of the current Patent Act, but that the duty had been breached. Justice Mactavish cited with approval Justice Hughes’ analogy in G.D. Searle & Co. v. Novopharm Ltd., 2007 FC 81 between patent examination and ex parte motions before the court. On the ultimate question of the scope of the duty, Justice MacTavish held as follows:

The duty of good faith imposed by paragraph 73(1)(a) of the post-1996 Patent Act requires that this prior art be fully and fairly described by applicants and their agents when answering requisitions from the Patent Office.

Interestingly, although the court found that the Wenk article did not anticipate the claims of the '492 Patent or render them obvious, since it said "nothing" about the synergistic effect of combining the compounds, the '492 Patent Application was deemed to be abandoned since the applicant had failed to specifically cite or discuss the Wenk article in response to the examiner’s obviousness rejection. Justice Mactavish held that it was the one study that was directly relevant to the office action. The fact that Wenk was previously disclosed to the examiner was not an answer to the applicant’s statements that the prior art "clearly" taught away from combining the compounds. In light of the teachings of Wenk, Justice Mactavish held that this statement was not a fair representation of the prior art. So despite her finding that the claims were not anticipated, nor obvious in light of the Wenk reference, the patent application was deemed abandoned for lack of a good faith reply.

Accordingly, Lundbeck’s application for a prohibition Order in respect of the '492 Patent was dismissed.

This decision puts into question the prior understanding of the law that there is no positive duty by the applicant to provide relevant references to the patent office, absent a specific requisition by the examiner. This decision appears to impose a duty on the applicant to present ─ and accurately discuss ─ the relevance of the most pertinent prior art it is aware of, and to ensure that any statements on the record accurately reflect its contents and do not mislead. One can not necessarily rely on simply placing the prior art on the record for the examiner to review and consider.

To read the full decision, please click here.