The '644 Patent covered the use of prasugrel (Eli Lilly's Effient) in combination with aspirin for diseases caused by thrombus or embolus. Prasugrel and aspirin were previously known to have an inhibitory effect on platelet aggregation. The '644 Patent claimed the novel combination of prasugrel and aspirin. Apotex made the following attacks on the patent's validity.
Patentable subject matter Apotex argued that the '644 Patent was invalid, as it claimed a "mere aggregate and not a patentable combination" and was therefore not an invention under Section 2 of the Patent Act. Based on expert evidence, Justice Manson found that the '644 Patent disclosed that the claimed combination resulted in an effect on platelet aggregation that was new, useful and more than the sum of the effects of each agent alone. He therefore rejected this ground of invalidity.
Obviousness The judge found that the claims were obvious. The inventive concept was found to be the combination of prasugrel and aspirin, which has a greater effect than the sum of the effects of each drug alone. Prasugrel belonged to a class of molecules called thienopyridines, two of which (ticlopidine and clopidogrel) had been successfully combined with aspirin for an antithrombotic effect. The judge found there was motivation to find the solution of the '644 Patent, as inhibiting two known platelet activation pathways using thienopyridine and aspirin together was known to result in improved therapies. Substituting one thienopyridine for another in combination with aspirin had also been successful. Therefore, although the exact effects of combining prasugrel with aspirin could not be predicted with certainty, a skilled person could reasonably expect the combination to achieve the same synergistic, therapeutic effect as clopidogrel (and possibly ticlopidine) and aspirin. Testing was done relatively quickly and, although technical, was based on well-known methods. Therefore, it was self-evident and obvious to try the combination of prasugrel and aspirin.
Sufficiency and overbreadth Apotex argued that:
- the specification of the '644 Patent did not instruct the skilled person on how to administer prasugrel and aspirin sequentially, as the time period between administrations would have to be determined experimentally; and
- the '644 Patent claimed more than what had been invented.
However, the expert evidence indicated that a skilled person would be able to determine the period using the '644 Patent and common general knowledge. Therefore, the judge found that the patent was not invalid for lack of disclosure or overbreadth.
As Apotex's obviousness allegation was found to be justified, the judge dismissed Eli Lilly's application for a prohibition order.
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(1) Eli Lilly Canada Inc v Apotex Inc, 2018 FC 736.
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