Federal Court of Appeal confirms that Eli Lilly's patent to atomoxetine is invalid for lack of utility
Geoffrey North and Edwin Mok
The Federal Court of Appeal recently released its decision in Eli Lilly and Company v Teva Canada Ltd, confirming the trial court’s finding that Canadian Patent No. 2,209,735 (the 735 patent), which claims a new use for an old medicine that has long been in the public domain (the use of atomoxetine for treating attention deficit hyperactivity disorder (ADHD) in three of its manifestations among all age groups), is invalid. We reported the lower Court’s ruling in a previous blog.
This appeal raised three principle legal issues. Namely, did the Judge err by: (i) misconstruing the patent’s promise by finding an implicit promise that atomoxetine “will work in the longer term”; (ii) requiring too high a standard of proof for utility; and (iii) deciding that Lilly could not rely on the sound prediction of the utility of the invention because Lilly had not disclosed the factual foundation for that prediction in the 735 patent?
The Court rejected all of Lilly’s arguments. As to the patent’s promise, the Court found that the trial judge did not construe the patent as promising more than its explicit promise that it will treat ADHD in some people. The trial judge had simply interpreted what “treatment” meant in the 735 patent in the context of ADHD, a chronic disorder requiring sustained treatment. He was therefore not adding any promise above and beyond that already expressed in the words of the 735 patent itself. Moreover, this argument could not assist Lilly in any event. The trial judge found that the evidence was insufficient to demonstrate that atomoxetine was an effective clinical treatment, regardless of the length of time for which it was taken.
As to the standard of proof for utility, Lilly argued that only a low level or scintilla of utility is required for the purpose of patentability. As such, Lilly argued that the trial judge erred by requiring evidence that was “sufficiently compelling to independently support the [patent’s] inventive promise.” The Court found that this argument could not succeed however, because the 735 patent specifically promised that atomoxetine is a clinically effective treatment of ADHD. Utility was therefore not to be measured against a hypothetical or theoretical standard lower than that promised in the patent. Although data from a pilot study was promising and “indicated a clinically and statistically significant response rate for atomoxetine over placebo”, it was proper for the trial judge not to infer from the limited experimental data that there was sufficient evidence that atomoxetine was a clinically effective treatment of ADHD.
Lastly, as to the issue of proper disclosure for sound prediction, Lilly argued that neither the Patent Act nor the Supreme Court’s jurisprudence requires disclosure of study results in a patent as a condition precedent to successfully invoking sound prediction as the basis of the utility of the claimed invention. The Court noted in response, however, that the Federal Court of Appeal has previously affirmed that a patentee must disclose in a patent a study that provides the factual basis for the sound prediction. In addition, the Court stated:
[I]f disclosure in the patent of the factual basis of the prediction of utility was not required for sound prediction, it would be difficult to see what Lilly could be said to have given to the public, in exchange for the grant of the monopoly, that it did not already have. When utility is based on sound prediction, disclosure of its factual foundation goes to the essence of the bargain with the public underlying patentability.
We look forward to the Supreme Court’s decision in the sildenafil citrate (Viagra) case, where we will be provided with further guidance on the issue of sound prediction.