CASE: ratiopharm inc. v. Pfizer Limited

DRUG: amlodipine besylate (NORVASC®)

NATURE OF CASE: Impeachment Action – s. 60(1) Patent Act

SUCCESSFUL PARTY: ratiopharm inc.

DATE OF DECISION: July 8, 2009 (public reasons released August 12, 2009)


On July 8, 2009, the Federal Court (Hughes J) granted ratiopharm inc. a declaration under section 60(1) of the Patent Act (the "Act") that Canadian Patent No. 1,321,393 (the "’393 Patent") is invalid. The parties agreed that the validity of the ’393 Patent would be determined solely on the basis of the validity of the claim to the besylate salt of amlodipine (claim 11). The ’393 Patent had been the subject of previous litigation under the Patented Medicines (Notice of Compliance) Regulations wherein Pfizer Ltd. successfully obtained prohibition orders against ratiopharm inc. and Pharmascience Inc.

Before addressing the invalidity issues, the Court embarked on an extensive analysis of the inventors’ work leading up to the patent application filing and compared that to the specification of the ’393 Patent. Hughes J concluded that the specification of the ’393 Patent differed from what the inventors actually did and used this as the "essence of the facts" against which he assessed the validity of the claims.

The Court then addressed the issues of validity, finding as follows:

Obviousness – The Court held that the inventors used routine and well-known processes to screen and test the salts of amlodipine. Applying the "obvious to try" test from Apotex Inc. v. Sanofi-Synthelabo Canada Inc., [2008] 3 S.C.R. 265, the Court concluded that the ’393 Patent was invalid for being obvious.

Validity of Selection – The Court held that the ’393 Patent was not a valid selection patent stating "it is difficult from the face of the patent and unsupportable from the evidence to state that besylate is sufficiently superior to the other salts…to make it 'unique' or 'outstanding' or 'particularly suitable'".

Utility – The Court held that the ’393 Patent lacked utility as it failed to fulfill the promise of the patent. Specifically, the evidence did not support the conclusion that the besylate salt had unique or outstanding properties.

Sufficiency of Disclosure – The Court did not address whether the ’393 Patent disclosed what the invention is and how to work it but rather focussed its attention on whether the specification disclosed the invention as "contemplated by the inventors" (per s 34(1)(a) of the Act). Noting the discrepancies between the inventors' work and the specification, the Court ruled the ’393 patent was invalid for insufficiency.

Section 53(1) of the Patent Act The Court held that the ’393 Patent contained misstatements that served to enhance the alleged uniqueness of the besylate salt. Attempts by the inventors to distance themselves from the patent drafters gave the Court the impression that Pfizer knew there were problems with the patent. On this basis the Court held the misstatements were made for the purpose of misleading and, therefore, the ’393 Patent was invalid for failing to comply with section 53(1) of the Act.


The decision is not yet available on the Federal Court website but will have the citation 2009 FC 711