Hoffman-La Roche Limited v. Apotex Inc., 2013 FC 718

In this application brought under the PM(NOC) Regulations Roche sought to prohibit the Minister of Health from issuing a Notice of Compliance to Apotex’s valganciclovir hydrochloride tablets until the expiry of Roche’s Canadian Patent No. 2,154,721 (the '721 Patent). The ‘721 patent covers valganciclovir hydrochloride, sold in Canada under the brand name VALCYTE for the treatment of certain herpes virus infections. Roche brought this application in response to Apotex’s Notice of Allegation (“NOA”) alleging non-infringement and invalidity on the grounds of anticipation and obviousness.

The Court dismissed Roche’s application for prohibition, and held that Apotex’s allegations of invalidity of the ‘721 patent on the grounds of anticipation and obviousness are justified. In addition, the Court found in the alternative that Apotex’s allegations of non-infringement of the ‘721 Patent are also justified.

Anticipation

Despite Roche’s attempts to characterize the ‘721 patent as a selection patent claiming certain species of the EP 375,329 patent (EP 329 patent), the Court ultimately found that the ‘721 patent was not a selection patent but merely an improvement over its larger parent compound ganciclovir from which it was derived (see [171] and [174]). Therefore, the Court assessed the validity of the ‘721 patent as an ordinary patent in this case [177].

The Court agreed with Apotex that Roche’s ‘721 patent was anticipated by EP 329. The Court held that even though the disclosure of EP 329 did not contain an exact description of the invention of the ‘721 patent, it was sufficient “so that the POSITA, willing to understand it, would understand what was invented, without trial and error” ([230] and [234]). Therefore, the court found that EP 329 on a balance of probabilities provided sufficient disclosure such that a POSITA reading it would understand its invention without trial and error [234].

Regarding enablement, the Court found that the POSITA using the disclosure in EP 329 would engage in routine chemistry to manufacture the compound claimed in the ‘721 patent without any inventive step (as the compound was already explicitly disclosed and its advantages explained). Therefore, the Court found that EP 329 also provided sufficient enablement.

Obviousness

The Court applied the Sanofi obviousness test and found that the inventive concept of the ‘721 patent, “the invention of valganciclovir, a stable prodrug with low toxicity and improved oral bioavailability over ganciclovir” [132], was obvious based on prior research in the field of drug testing for the treatment of the herpes virus. Specifically, the Court applied the obvious-to-try test adopted in Sanofi, because the state of the art at the relevant time involved the development of many different chemical compounds which required significant experimentation. Of the three main factors that comprise the obvious-to-try test, the Court assigned the most weight to the first factor: the Court  stated the question regarding this factor as “whether it was more or less self-evident that if the skilled person added the mono-L-valine ester to ganciclovir, the resulting compound would have improved bioavailability and stability and low toxicity over ganciclovir” [274]. The Court concluded that it was self-evident that adding the mono-L-valine ester would work, based on research on a chemically-related compound as well as EP 329 [353].

Regarding the second and third factors of the obvious-to-try test, the Court found that rather routine trials were carried out to reach the inventive concept of the ‘721 patent [348]. In terms of whether there was motivation in the prior art to find the solution that the ‘721 patent addresses (i.e. improving the bioavailability of ganciclovir), the Court noted that there was ongoing research and competition among drug developers and manufacturers before the time that this patent was filed. Specifically, there was a strong motivation among drug makers to improve ganciclovir [352].