- Sildenafil Citrate (TP)
- Sildenafil Citrate TEVA
- Sildenafil Citrate (GS)
- Tadalafil TEVA
- Tadalafil ACCORD
- Tadalafil DAILY
- Vardenafil ZYDUS
Federal Court Judge Dismisses Final Prohibition Application in CIALIS PM(NOC) Proceeding 2015-04-01
On February 23, 2015, the Federal Court released its judgment in the latest of three PM(NOC) proceedings relating to Eli Lilly’s CIALIS (tadalafil) patents. The previous two decisions were discussed in snIP/ITs posted on January 26, 2015 and March 30, 2015.
In the latest decision, Eli Lilly Canada Inc. v. Mylan Pharmaceuticals ULC, 2015 FC 178, Justice de Montigny found that Mylan’s allegations of non-infringement and obviousness were justified, and dismissed Lilly’s application for an order prohibiting the Minister of Health from issuing a Notice of Compliance to Mylan until expiry of Canadian Patent No 2,379,948 (the “’948 Patent”). The ‘948 Patent claims a tadalafil tablet formulation and its use to treat erectile dysfunction (“ED”).
Justice de Montigny’s decision emphasizes the critical role experts and expert reports play in PM(NOC) proceedings. As counsel for Lilly stated during his submissions, “a lot of it just comes down to which expert the Court is going to go with”. Justice de Montigny ultimately preferred the evidence of Mylan’s experts, finding that Lilly’s evidence on several key issues was incomplete or speculative.
Infringement – Hydrophobic Binder
Lilly argued that while Mylan’s formulation contains more than the claimed amount of hydrophobic binder, the compound is working as both a binder and solubilizer. Lilly’s expert opined that “one would expect” a proportion of this compound to act as a solubilizer, with the remaining proportion acting as a binder falling within the claimed amount.
Justice de Montigny rejected Lilly’s argument, noting that “[s]peculation, even by experts, is not evidence, and is clearly not sufficient to meet the burden of proof in infringement cases.” He held that there is no evidence that the compound acts as a solubilizer. Further, even if the compound did act as a solubilizer when taken by the patient, all of the compound acts as a binder during the production of the tablets.
Infringement – Particle Size
The parties disagreed regarding the moment at which particle size should be measured. Lilly argued that the particles must be measured after being pressed into tablets, since a purposive construction requires measurement at the point where bioavailability can be affected. Justice de Montigny rejected this construction, observing that it is not supported by the language of the patent or by the experts. He held that the patent’s language “clearly indicates that the particle size claimed is of the tadalafil particles going into the formulation”.
The Court accepted the evidence of one of Mylan’s experts that the analysis of particle size found in Mylan’s ANDS is “probably the most reliable measurement of the particle size distribution of Mylan’s drug substance”. The analysis placed Mylan’s tadalafil particle size well outside that claimed in the patent. Since Lilly did not submit pre-formulation particle size test results, the Court held that Lilly had failed to discharge its burden to establish that Mylan’s allegations of non-infringement are not justified.
The parties generally agreed that the inventive concept of the ‘948 Patent is a formulation with improved dissolution and stability of tadalafil achieved by reducing its particle size and formulating it with specific excipients. Although Lilly argued that there is an infinite number of excipient combinations available to a formulator when formulating a new drug, the Court noted that a leading treatise on the subject explained that the total number of significant excipients in use is less than 25. As such, Justice de Montigny held that the choice of excipients and their specific amounts was well within the common general knowledge of the skilled person.
Justice de Montigny further held that the choice of excipients would have been obvious to try because “a person skilled in the art would have had a high expectation of success in using the excipients and the surfactant of the ‘948 Patent in obtaining a tadalafil formulation with the desirable bioavailability, and that it was indeed more or less self-evident that such a strategy ought to work.”