Federal Court reiterates full, frank and fair disclosure requirement in patent prosecution

In the public reasons released earlier this week, the Federal Court reiterated its view that the prosecution of a patent application was analogous to an ex parte court proceeding, and that applicants and their agents are required to make a full and fair description of the prior art when answering an examiner's requisitions. 

In Lundbeck Canada Inc. v. ratiopharm Inc., 2009 FC 1102, the applicant Lundbeck sought orders of prohibition against ratiopharm under the Patented Medicine (Notice of Compliance) Regulations in respect of two patents relating to memantine hydrochloride, used in the treatment of Alzheimer's disease. The applications were dismissed in respect of both patents. With respect to one of the patents, Justice Mactavish reviewed the prosecution history of one of the patents, and held that it was invalid on the ground that the patent application had been irrevocably abandoned because Lundbeck had failed to respond in good faith to an examiner's requisition, as required by s. 73(1)(a) of the Patent Act.

During prosecution, the examiner had objected to the pending claims as being obvious in view of the prior art, because the claims were directed to an aggregation of known compounds. In response, the patent applicant argued that prior art taught away from the combination:

... It is therefore of prime importance to note that, at that time, there were numerous articles in the prior art which warned against the combination of NMDA antagonists and AChE [or acetylcholinesterase] inhibitors because NMDA antagonists attenuated the effect of AChE inhibitors, i.e. NMDA antagonists rendered AChE inhibitors ineffective...

In support of this assertion, the response included discussion of certain prior art references, and concluded:

... it would thus have been counter-intuitive and definitely improbable that, in view of the prior art available at the time of filing, one skilled in the art would have been prompted to combine a NMDA antagonist with an AChE inhibitor to achieve the claimed composition... Indeed, the prior art clearly teaches away from the combination of a NMDA antagonist with an AChE inhibitor as claimed in the instant application.

However, the response omitted discussion of another prior art reference, Wenk, that, in the Court's view, tended to the opposite conclusion, although it did not anticipate or render the claims obvious. Wenk was acknowledged to be within the knowledge of the inventors by the time of filing, and had been identified to the Canadian patent examiner, although a copy had not been provided.

The Court, stating its agreement with an earlier decision of Justice Hughes in G.D. Searle & Co. v. Novopharm Ltd., 2007 FC 81, rev'd 2007 FCA 173, found that the requirement of s. 73(1)(a) of the Patent Act to "reply in good faith to any requisition made by an examiner in connection with an examination" created a duty of candour on the part of the applicant. This duty involved "full, frankand fair" disclosure of all appropriate facts as in an ex parte court proceeding, so as to allow the examiner to make an appropriate assessment of the application. 

Because the wording of the applicant's response to the examiner's requisition implicated the teachings of the prior art "as a whole" at the time of filing, the failure to discuss Wenk in the response was found to lack good faith. Although Wenk itself was not sufficient to render the claims invalid, given the wording of the response it at least as important as the other prior art references discussed in the response. Therefore, the response did not fairly or accurately represent the state of the prior art, and accordingly the application was abandoned for failure to respond in good faith.

Lundbeck Canada Inc. v. ratiopharm Inc., 2009 FC 1102

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