While a drug dispute concerning one of Australia's major sports has been hogging all the headlines of late, another much more lucrative (and interesting, at least fromScintilla's perspective) one has been playing out in the courts between AstraZeneca and several generic companies over AstraZeneca's cholesterol-lowering drug, rosuvastatin (brand name: CRESTOR).

As we previously reported, the first two rounds were won by the generic companies, with AstraZeneca's low dose patent for rosuvastatin being found invalid at both first instance and on appeal. However, in mid-March the High Court granted AstraZeneca special leave to appeal two aspects of the Full Federal Court's decision.

The first issue for the High Court to consider will be the Full Court's treatment of common general knowledge and section 7(3) prior art information in the context of a lack of inventive step argument. 

There were two key publications that the parties' experts had identified as relevant prior art: one of these publications would have led to a finding that AstraZeneca's invention was 'obvious', whereas the other would not. AstraZeneca argued that the Full Court applied the wrong test when determining inventive step because it did not consider the choice that the person skilled in the art would have had to make in practice between the two prior art publications. In other words, the question that the High Court will have to consider is whether, where there are multiple relevant pieces of section 7(3) prior art information that lead down different paths, the court must take the availability of those different paths into account when determining whether there is an inventive step.

That question is different from the 'starting point' issue which received so much attention at first instance and on appeal. The 'starting point' issue is also likely to make an appearance before the High Court, as Apotex has indicated that it will file a notice of contention to raise that as an additional matter for consideration. 

A second issue that will be aired before the High Court is whether AstraZeneca is entitled to the low dose patent. At both first instance and on appeal, it was found that the low dose patent was in fact invented by employees of another company, Shionogi. None of these employees were named as inventors of the low dose patent, and so AstraZeneca was found not to be entitled to that patent.

The question for the High Court on this issue will be whether section 22A of thePatents Act, which provides that a patent is not invalid merely because it was granted to a person who was not entitled to it, applies to save the low dose patent from revocation. This issue might seem relatively straightforward at first glance, but it is complicated by the fact that s22A only came into force on 15 April 2013, after the first instance judgment was delivered and the low dose patent was revoked. 

So if AstraZeneca succeeds before the High Court, what then? Well, since the Full Court found that AstraZeneca had made out its infringement case against the generic companies, AstraZeneca may have a claim for damages against those generic companies that started selling generic versions of rosuvastatin after the trial judgment in 2013. Given that Crestor is a blockbuster drug for AstraZeneca, the stakes are high for all parties.