In Idenix Pharmaceuticals, Inc v Gilead Pharmasset LLC, 2017 FCA 161, the Federal Court of Appeal affirmed the Federal Court’s decision that Idenix’ Canadian patent No. 2490191 was invalid for lack of utility and insufficiency of disclosure. Both Idenix and Gilead held patents for compounds that helped treat against the family of flaviviridae viruses, which includes Hepatitis C, and each alleged that the other’s patent was invalid.

Idenix was not successful on either point, both at trial and on appeal.  The Federal Court of Appeal upheld the lower court’s holding that Gilead’s patent was valid, and also upheld the finding that Idenix’ ‘191 patent was invalid for insufficient disclosure for failure to disclose how to make the compound claimed in the patent.  Although the utility of different pathways for synthesizing the drug at issue was shown after the filing of Idenix’ patent application, the court relied on Novopharm Limited v. Pfizer Canada Inc., 2010 FCA 242 and held that the proper date for assessing sufficiency of disclosure is the application’s filing date.  In the case of Idenix’s ‘191 patent, as of the filing date, a person skilled in the art would have experienced an undue burden in synthesizing the compound claimed in the patent given the lack of guidance in the specification.  Consequently, the Federal Court of Appeal affirmed the invalidity of the ‘191 patent.