The Best Defence Is A Good Offence: Gilead Invalidates Patent Threatening its SOVALDI Product

SofosbuvirOn November 2, 2015 Justice Annis released a 326-page decision holding that Canadian Patent No. 2,490,191 is invalid (2015 FC 1156). Gilead sells the antiviral drug sofosbuvir in Canada under the brand name Sovaldi, for use in combatting Hepatitis C virus (HCV). Gilead commenced an action to impeach the 191 Patent because the manufacture, use or sale of Sovaldi may have been seen as infringing. The owner of the 191 Patent, Idenix, counterclaimed for a declaration that Gilead infringed the 191 Patent, and also alleged that Gilead’s Canadian Patent No. 2,527,657, which claims sofosbuvir, is invalid. Justice Annis dismissed Idenix’s counterclaims (see our blog post here), but held the 191 Patent would be infringed by Gilead had it been valid.

The 191 Patent discloses nucleoside analogues of D-ribose 2’-Methyl, 2’-Hydroxyl (2’-C-Me/OH) having antiviral activity against HCV. Its claims are limited to analogues containing a fluorine atom (F) at the 2’ position (2’-C-Me/F). The 657 Patent discloses 2’-C-Me/F compounds having anti-viral activity against HCV and includes claims to sofosbuvir.

Lack of Demonstrated or Soundly Predicted Utility

Idenix conceded that it had not made or tested any compounds within the claims of the 191 Patent prior to the filing date. Idenix argued the utility of 2’-C-Me/F compounds could be predicted based on successful testing of 2’-C-Me/OH compounds because fluorine (F) is an isosteric mimic of a hydroxyl group (OH). Justice Annis dismissed this argument:

[283] I find that Gilead has demonstrated that Idenix had no sound line of reasoning to predict the antiviral activity of the 2’-C-Me/F compound based on its hypothesis of “steric mimicry.” Professor La Colla, as the only one of four inventors that testified, did not demonstrate that the inventors considered that their prediction based on steric mimicry was anything more than a possibility. The contemporaneous documentation also demonstrates that the inventors believed that the hydroxyl group at the 2’ (down) position on the sugar ring was essential. The Court similarly finds Dr. Lamarre’s opinion of sufficient steric mimicry such as to predict the antiviral activity of the 2’-C-Me/OH compound in the 2’-C-Me/F nucleoside at best, to be an educated guess, not supported by the common general knowledge.

Having found the 191 Patent invalid for a lack of sound prediction, Justice Annis considered, in obiter, whether Idenix was required to disclose the sound prediction and if so, whether that requirement was met. Without addressing the SCC’s decision in Monsanto, Justice Annis followed the reasoning in AstraZeneca/esomeprazole, in which Justice Rennie held that the requirement to disclose the basis for a sound prediction in a patent only applies to new use claims, not compound claims:

[380] … Accordingly, as the ‘191 Patent relates to a sound prediction of a new composition, there is no utility disclosure requirement. I assume that this exemption from disclosure applies both to the factual basis and the line of reasoning.

However, Justice Annis went on to consider whether, if a disclosure requirement does exist, Idenix had in fact disclosed a sound prediction:

[412] The Court concludes that Idenix has not disclosed a sound prediction of utility in the 2’-C-Me/F nucleoside as it had not disclosed its factual basis for its position in June 2003 that the 2’-C-Me/OH nucleoside had antiviral activity against HCV.

Sufficiency of Disclosure

Justice Annis’s sufficiency analysis focused on whether the 191 Patent sufficiently disclosed how to make 2’-C-Me/F nucleosides. Justice Annis concluded that the 191 Patent did not disclose how to make the claimed compounds. Idenix argued that the common general knowledge and routine experimentation could supplement the 191 Patent in order to meet the disclosure requirements. Justice Annis considered and dismissed this argument:

[547] … A wealth of literature available to the skilled person setting out choices is not any indication of whether the synthesis of the compound was common general knowledge. Certainly, routine trial and error experimentation does not occur where there is an excess of choice, not to mention that an excess of choice entirely excludes the possibility that the disclosure of the 2’-C-Me/F compound could be made by common general knowledge.

[775] The Court concludes that Idenix’s claim that common general knowledge and permissible experimentation supplemented the written disclosure, thereby providing enabling disclosure of how to synthesize the 2’-C’-Me/F nucleoside is not supported by the evidence. The disclosure of the synthesis of the 2’-C-Me/F compound in the ‘191 Patent is therefore, insufficient.

A copy of the Public Judgment and Reasons of Justice Annis can be found here.