Canada: Pharma In Brief - Canada: Federal Court Upholds Validity Of GLEEVEC® Patent

Case: Teva Canada Limited v. Novartis AG, Apotex Inc. v. Novartis AG

Drug: Imatinib Mesylate (GLEEVEC®)

Nature of case: Patent Impeachment Actions and PM(NOC) Prohibition Applications

Successful party: Novartis AG

Date of decision: February 19, 2013

Summary

Teva Canada Limited ("Teva") and Apotex Inc. ("Apotex") wish to sell generic versions of GLEEVEC®, a highly effective drug for the treatment of chronic myeloid leukemia (CML). The active ingredient in GLEEVEC® is imatinib mesylate. Imatinib and its salt, imatinib mesylate, are protected by Canadian Patent No. 2,093,203 (the "'203 Patent") owned by Novartis AG ("Novartis").

Teva and Apotex commenced actions against Novartis seeking declarations under s. 60(1) of the Patent Act, R.S.C. 1985, c. P-4 that the claims of the '203 Patent are invalid (the "Impeachment Actions"). Teva and Apotex also served Novartis with Notices of Allegation in respect of the '203 Patent. In response, Novartis defended the Impeachment Actions and brought applications under the Patented Medicines (Notice of Compliance) Regulations ("NOC Regulations") for an Order, inter alia, prohibiting the Minister of Health from authorizing Teva and Apotex to market imatinib until the expiry of the '203 Patent (the "Prohibition Applications"). The Impeachment Actions and the Prohibition Applications were consolidated for trial and heard by Justice Snider.

The Court concluded that the utility of Claims 5, 7, 29, 44 and 46 of the '203 Patent had been demonstrated or could be soundly predicted as of the filing date, and that the '203 Patent met the disclosure requirement of s. 27(3) of the Patent Act. The Court also held in separate Reasons for Judgment that Teva and Apotex's allegations of invalidity were not justified in light of its decision in the Impeachment Actions.

Background of the '203 Patent

The essence of the '203 Patent is selective inhibition of particular protein kinases that are responsible for transmitting signals to the nucleus to cause cell growth and proliferation. The primary kinases referred to in the '203 Patent are ABL Kinase, PDGF-R Kinase and the family of PKC Kinases, all of which were being investigated for their connection to various forms of cancer at the relevant date. In April 1992, a patent was filed in Switzerland for a group of PKC inhibitors (the "Group 1 Compounds"). It is the priority application to which the '203 Patent refers.

Two important discoveries occurred in the year between the filing of the priority application and the Canadian patent application: (1) chemists created molecules that could inhibit PDGF-R Kinase and ABL Kinase in addition to PKC; and (2) the synthesis of a molecule that was selective for PDGF-R and ABL Kinase, but did not inhibit PKC (the "Group 2 Compounds"). After the Canadian filing date of the '203 Patent, the Novartis scientists focussed primarily on compounds that came to be known as the Group 2 Compounds. Over the next year, further testing demonstrated that imatinib was the molecule of greatest interest. The Court noted that imatinib has revolutionized the treatment of CML.

Claims Construction

The Court began by construing the claims of the '203 Patent. The Court noted that the claims – and not the disclosure – are the essence of a patent and it is the claims that must be interpreted. While the specification, as a whole, will describe the invention, the scope of the monopoly is defined by the claims. The Court also emphasized that a patent must be read with a mind willing to understand.

The experts agreed that Claims 9-27 and 34-39 cover compounds that are within Group 1. They also agreed that Claims 28-33 cover compounds that are within Group 2 and that Claim 29 is to the compound imatinib. The experts disagreed on the proper construction of Claim 46 (which includes a claim to the use of imatinib to treat CML), whether the inventors of the '203 Patent were promising guaranteed therapeutic treatment, and whether ABL inhibition testing had in fact been carried out.

The Court held that: (1) the meaning to be ascribed to Claim 46 is that a Group 2 Compound may be useful to treat either PDGF-R or ABL tumours (rather than being useful to treat both tumours, which was the position advanced by Teva and Apotex); (2) the phrase "the compounds...can be used" means that the compounds have the potential to be used for the purposes stated in the '203 Patent; and (3) ABL inhibition testing had in fact been carried out.

Utility

The Court briefly summarized the principles relating to utility in Canada, including demonstrated utility and sound prediction. The Court cautioned that sound prediction is not a free-standing statutory requirement and that its introduction into Canadian law was not to give a "crushing hammer" to those who challenge patents.

The Court rejected Teva and Apotex's argument that every claim must have the same utility, and thus the same promise. The Court noted that the '203 Patent is primarily a compound patent, with the use claims, the process claim and the medicinal composition claims arising from the properties of the compounds. Following the approach of Justice O'Reilly in Pfizer Canada Inc. v. Apotex Inc., 2007 FC 26, aff'd 2007 FCA 195 ["Sildenafil"], the Court held that the '203 Patent contained different levels of utility according to the type of claim at issue: (1) for the compound claims (Claims 1-39), the promise or utility is that the compounds will selectively inhibit PKC, PDGF-R or ABL; (2) for the use claims (Claims 45-48), the promise or utility is that the compounds have the potential for in vivo treatment of the enumerated conditions; and (3) for the process claim (Claim 44), the utility or promise is to provide a process to make the claimed compounds.

Teva and Apotex argued that having more than one promise is inconsistent with the decision of Eli Lilly Canada Inc. v. Novopharm Ltd., 2011 FC 1288 ["Zyprexa"]. However, the Court held that in Zyprexa, the basis of the selection was that olanzapine treats schizophrenia in the clinic better than other antipsychotic drugs, and thus there was no basis on which to apply a different promise to any of the claims.

The Utility of the Compound Claims

Teva and Apotex accepted that in vitro activity of imatinib (Claim 29) was demonstrated or soundly predicted as of the filing date. Since the Court found the promise of the Group 2 compound claims is that they will be selective inhibitors of either PDGF-R or v-ABL, it followed that the utility of at least Claim 29 was acknowledged by Teva and Apotex. The Court went on to consider whether the utility of all of the Group 2 Compounds had been demonstrated as of the Canadian filing date.

In reviewing the in vitro testing, the Court held that it is inappropriate to isolate one inconclusive test and hold it up as a demonstration of lack of utility, without examining it in the context of all the test results for that particular compound. The Court concluded that as of the Canadian filing date: (1) the utility of the compounds of Claims 9-27 and 34-39 as selective inhibitors of PKC and of Claims 28-33 as selective inhibitors of ABL and PDGF-R had been demonstrated; (2) the utility of Claims 5 and 7 (the smaller genus claims) as selective inhibitors could be soundly predicted; and (3) the utility of all of the compounds of Claims 1-4 (the larger genus claims) had neither been demonstrated nor soundly predicted.

The Utility of the Use Claims

The Court considered whether the use of the Group 2 compounds to treat CML was soundly predicted. The factual basis consisted of in vitro testing that demonstrated the Group 2 Compounds selectively inhibited the v-ABL kinase, as well as some in vivo rat testing and some limited toxicology studies. The evidence further showed that a compound that inhibits v-ABL will also inhibit BCR-ABL, which had been linked conclusively to CML. This formed the articulable line of reasoning from which it could be soundly predicted that any of the Group 2 Compounds would be useful in the treatment of CML.

In considering the third part of the sound prediction test – the disclosure requirement – the Court held that the fact that all of the testing was not described in the '203 Patent was not fatal to Novartis' case. In particular, the Court noted that the in vivo testing carried out was not essential to establish the line of reasoning given the strength of the common general knowledge surrounding the link between BCR-ABL and CML. The Court distinguished this case from the decision of Justice Hughes in Eli Lilly Canada Inc. v. Apotex Inc., 2008 FC 142, aff'd 2009 FCA 97 ["Raloxifene"] on the facts. The Court held that the question to be asked is whether "sufficient information" was disclosed to allow the person of ordinary skill in the art to make the sound prediction.

Sufficiency of Disclosure

Teva and Apotex raised a number of arguments attacking the sufficiency of disclosure of the '203 Patent, all of which were rejected by the Court. With respect to their assertion that the '203 Patent should have disclosed that imatinib was the best of the six Group 2 Compounds, the Court held that in the face of the evidence that all six compounds were effective inhibitors, this argument could not be sustained. With respect to the argument that the '203 Patent fails to disclose the minor problem of poor solubility of imatinib, the Court held that this was not critical to the understanding or practice of the invention and was a matter of simple trial and error. Although the Supreme Court stated in Teva Canada Ltd. v. Pfizer Canada Inc., 2012 SCC 60 ["Viagra"] that a skilled reader should not have to engage in a minor research project, the Court held that this left open the possibility that some trial and error may be permitted. The Court was satisfied the inventors had not attempted to "hide" the true invention or "game" the system.

Conclusion

The Court dismissed the Impeachment Actions on the basis that one or more of the claims of the '203 Patent were found to be valid. The Court's reasoning highlights an ongoing tension in the jurisprudence surrounding doctrines such as the "promise of the patent", sound prediction and the "enhanced disclosure" requirement for sound preduction. While this is a positive outcome for Novartis, it remains to be seen whether this decision will add more predictability for other pharmaceutical patentees seeking to enforce their patent rights in Canada.

Link to decision:

Teva Canada Limited v. Novartis AG, 2013 FC 141

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