AUSTRALIA Trends and Developments Contributed by: Ben Miller, Stephen Rohl, Katie Pryor and Jenny Wong, Maddocks
and Sandoz have been involved in a number of disputes regarding rivaroxaban, including in the UK, where the UK High Court revoked Bayer’s patents. The case concerned Australian Patent No 2004305226 (the “226 Patent”) for a formula - tion, and Australian Patent No 2006208613 (the “613 Patent”) for a once-a-day dosing regimen. At first instance, Justice Rofe rejected an obvi - ousness challenge based on the common gen - eral knowledge (CGK) together with WO 919, the compound patent which disclosed rivaroxaban as a particularly promising candidate. In her reasoning, Justice Rofe accepted that WO 919 would be of interest to a drug development team seeking to develop a new antithrombotic drug, and that the skilled reader would likely focus on rivaroxaban when selecting lead can - didates to take into further drug development work. Justice Rofe then went on to apply the “reformulated Cripps question”, finding that: • the well-known standard series of steps of drug development were not routine steps; and • Bayer’s drug development journey was more akin to a “voyage of discovery” than “working towards the invention with an expectation of success”. On appeal, the Full Court found that Justice Rofe had placed too much emphasis on “the risk of failure to gain regulatory approval which is inherent in any drug development project”, and what would have been undertaken as a matter of course following the selection of rivaroxaban as a lead candidate. Further, the Full Court confirmed that the “rel - evant expectation” should be measured against
the ordinary level of expectation and risk inher - ent in routine work in the field. It is not necessary to know a particular outcome at the outset of the hypothetical task. Rather, the Full Court stated the question as whether a person skilled in the art with the relevant CGK, would have been directly led, as a matter of course, to develop rivaroxaban in the expectation that it might pro - duce a useful alternative (or better drug than) the existing compounds for the treatment of throm - boembolic disorders. In the absence of any evidence of any particu - lar problem or difficulty overcome in arriving at a suitable formulation (using a standard wet granulation process) or an (obviously desirable) once-a-day dosing regimen, the Full Court found that these matters would have been arrived at in the course of conventional clinical trials. Bayer has applied to the High Court of Australia for special leave to appeal. Ascertaining prior art for pre-Raising the Bar patents In the same case, the Full Court addressed the standard to be applied in determining whether the person skilled in the art could be reason - ably expected to have “ascertained” a prior art document, which is a prerequisite for consider - ing obviousness in light of the prior art. At first instance, Justice Rofe had accepted that a person skilled in the art would have conduct - ed searches on patent databases using search terms including factor Xa inhibitors, and that the search would have returned results that included WO 919. She accepted that Sandoz’s expert, Professor Roberts, had reviewed the search of the patent database, identified WO 919 as a top priority, and had done so without the benefit of hindsight. However, Justice Rofe found that
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