Omeprazole Formulation Patent Found Valid and Infringed

  • March 16, 2015

Astrazeneca Canada Inc. v. Apotex Inc., 2015 FC 322 (Barnes, J.)

March 16, 2015

Gunars Gaikis, Nancy Pei, Mark Biernacki and Urszula Wojtyra for AstraZeneca Canada Inc., Aktiebolaget Hässle and AstraZeneca AB
Harry Radomski, Ben Hackett, Sandon Shogilev and Daniel Cappe for Apotex Inc.

AstraZeneca Canada Inc., Aktiebolaget Hässle and AstraZeneca AB (collectively, "AstraZeneca") sued Apotex Inc. for infringing Canadian Patent No. 1,292,693. Apotex defended the suit on the basis that the 693 Patent was invalid and not infringed. The proceedings were bifurcated and this decision only dealt with the issue of liability. The patent was found to be valid and infringed.

The claims of the 693 Patent in issue, Claims 1, 5, 6, 13 and 19, relate to enteric-coated formulations of omeprazole which comprise an omeprazole core region that can include an alkaline reacting compound (ARC), "an inert subcoating which is soluble or rapidly disintegrating in water disposed on" the core containing omeprazole and an outer enteric coating.

In his 176-page decision, Justice Barnes conducted an extensive review of the evidence presented in the case; the highlights of his findings and conclusions are as follows.

Claim construction

  • The "subcoating" "disposed" on the core could include coatings that formed in situ during the manufacture of the product.
  • The word "inert" as used in the claims would be understood by a person of skill to mean that the subcoating was not reactive with the constituents to the extent it would adversely affect the enteric coat or the omeprazole core, and not that the subcoating was unreactive with all formulation constituents.
  • Small gaps or holes in the subcoating would be permissible as long as the function of the formulation was not compromised.

Validity

  • The 693 Patent was not invalid on the basis of lack of novelty. European Patent Application 124,495 did not anticipate the 693 Patent because it did not disclose the "subcoating" feature of the 693 Patent.
  • The 693 Patent would not have been obvious to the skilled pharmaceutical formulator. Omeprazole was a difficult API to formulate and not all of its idiosyncrasies were known in the prior art. Although the person of skill was aware of enteric coats, ARCs and subcoats in various formulation applications, he would not have been drawn immediately and without difficulty to combine those elements to solve the issues presented by omeprazole.
  • The inventor evidence supported a finding of non-obviousness. The research team at Hässle explored a number of options before it found an omeprazole formulation that was viable.
  • Claim 1 was not overbroad or ambiguous because AstraZeneca conceded a person of skill would not know without further testing whether any particular claimed formulation would actually work. Routine stability and gastric acid testing to know whether a formulation actually worked does not mean the claim was overbroad or unclear.
  • The 693 Patent did not lack utility; it did not contain a promise that every omeprazole formulation with the structural features of Claim 1 would fulfill the objectives of good storage stability and gastric acid resistance; these properties would be the expectation and not the inevitable result.

Infringement

  • Apo-Omeprazole infringed the 693 Patent.
  • The criticisms against the evidence of AstraZeneca's expert, Dr. Davies, who tested the Apotex pellets, were unwarranted. Apotex's experts went out of their way to identify issues with Dr. Davies' testing methods or results whether or not there was evidence to support their concerns. Further, although Dr. Davies' testing was conducted ex parte, the Apotex experts could have replicated his testing but failed to do so.
  • The MACP-PVP complex present in the sublayer of the Apotex pellets created by an in situ chemical reaction when the enteric coat was applied to the pellet cores met the structural "subcoating" element of the 693 Patent. Even though the sublayer contained minor defects, these were of no functional significance. In addition, all of Dr. Davies' tests considered together led to the conclusion that this sublayer comprised a continuous MACP-PVP subcoating of at least 2 microns thick.

Standing

Justice Barnes rejected Apotex's argument that neither AstraZeneca Inc. nor AstraZeneca AB had standing.

Foreign Issue Estoppel

Justice Barnes declined to apply the principles of issue estoppel and abuse of process by relitigation of findings of "fact" made by a US court in earlier litigation between the parties. There were practical problems, apparent in this case, of applying estoppel in a way that would actually protect judicial resources.

Remedies

  • No punitive damages were awarded on the basis Apotex failed to disclose the substitution of one ARC for another in the settlement of the earlier NOC proceeding because there was no evidence Apotex deliberately misrepresented its omeprazole formulation to deceive AstraZeneca.
  • However, the failure in Apotex's duty to inform AstraZeneca when the error was identified was an issue which might have a bearing on costs.
  • Apotex directly and consistently infringed and induced infringement of the 693 Patent by promoting and selling its Apo-Omeprazole capsules across Canada and by international sales since 2004.
  • The limitation period that applied in this case was six-years regardless of where the infringement took place.
  • AstraZeneca was entitled to elect an accounting of profits.

By: Cheryl Cheung