High Court delivers judgment in long-running rosuvastatin patent dispute

The High Court of Australia today delivered its much anticipated judgment in patent litigation relating to AstraZeneca's blockbuster lipid-lowering drug, Crestor® (rosuvastatin).¹

In long-running court proceedings, generic pharmaceutical suppliers including Apotex, Watson (subsequently named Actavis) and Ascent challenged the validity of a number of Australian patents owned by AstraZeneca (AZ) relating to rosuvastatin. At issue before the High Court was the validity of a patent covering methods of treating patients suffering raised cholesterol levels by administering once-daily rosuvastatin at a low starting dose of 5 or 10 mg (low-dose patent).

All five members of the High Court hearing this case upheld the finding of the Full Federal Court that AZ's low-dose patent was invalid for obviousness, or lack of inventive step.

What the High Court decided

The High Court's judgment provides important guidance on the approach to be taken when a court is called upon to decide whether or not the subject matter claimed in a patent involved an inventive step.

Under Australia's Patents Act 1990 (Cth) (Act) as it applies to the low-dose patent, the answer to that question depends upon whether the claimed subject matter would have been obvious to a notional skilled person in light of the common general knowledge (CGK) in their field. The Act permits regard to be had to documents, such as scientific articles and earlier patents, not forming part of the CGK that a skilled person could reasonably be expected to have "ascertained, understood and regarded as relevant". Importantly, under the version of the Act applicable to the low-dose patent, such documents may not be combined to establish obviousness. Each must be considered separately.

In finding the low-dose patent invalid for obviousness, the High Court rejected three key arguments advanced by AZ on the appeal.

First, AZ argued that the requirement to keep non-CGK documents separate applied not only when assessing the ultimate question of obviousness, but also at the antecedent stage of deciding whether a document would have been regarded as relevant by a skilled person. Rejecting that argument, the High Court confirmed that nothing in the Act precludes a skilled person from combining sources of information en route to concluding that a document is relevant to the problem addressed in a patent.

Secondly, AZ argued that where a literature review disclosed two or more alternative approaches to solving a problem, each of which would be considered relevant by a skilled person, it could not be "obvious" to adopt any one of them. That proposition was rejected by Chief Justice French, and in the joint judgment of Justices Gageler and Keane: if the claimed invention is obvious in light of CGK plus any one of several relevant documents, the patent will be held invalid.

Thirdly, AZ argued that the key document relied upon by the generic parties for their obviousness case failed to disclose the dosages of rosuvastatin claimed in the low-dose patent, and did not provide clinical trial data that a skilled person would require to identify a suitable starting dose. Rejecting that argument, the High Court pointed to expert evidence establishing that the relevant dosages would be identified through routine trials that a skilled person would conduct with an expectation of success in light of the document in question.

What the High Court did not decide

In their submissions to the High Court, the parties raised a number of other significant legal issues which, in the circumstances, the Court found it unnecessary to decide. In particular, the High Court found it unnecessary to address the question of whether or not, in separate litigation relating to Sanofi-Aventis' anti-clotting drug Plavix® (clopidogrel), the Full Federal Court had adopted the correct "starting point" when assessing obviousness.² That issue has significance for ongoing legal proceedings in which the Commonwealth is seeking compensation for losses it claims to have suffered when an interlocutory injunction granted to Sanofi-Aventis delayed the market entry of generic clopidogrel products in Australia.

Implications

Today's decision of the High Court is highly significant for the parties to the Crestor® patent litigation. The generic parties, including Apotex, Watson (subsequently named Actavis) and Ascent could be expected to now seek compensation for losses incurred during the period when their rosuvastatin products were held off the Australian market by an interlocutory injunction granted to AZ. It is conceivable that the Commonwealth may also decide to seek compensation in relation to additional costs to the Pharmaceutical Benefits Scheme during the period for which the interlocutory injunction remained in force.

The decision also has broader significance for Australian law on obviousness, which is frequently a critical issue in patent disputes. In the course of today's judgment, Chief Justice French emphasised that the notional "skilled person", by reference to whom obviousness is assessed, is simply a tool for analysis and should not be made unnecessarily complicated by reference to "human" characteristics. Further, Justices Gageler and Keane pointedly noted that the plain and ordinary meaning of statutory language is not to be ignored or diminished simply because that language relates to intellectual property rights.

Footnotes

¹AstraZeneca AB v Apotex Pty Ltd [2015] HCA 30.
²Apotex Pty Ltd v Sanofi-Aventis (2009) 82 IPR 416.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.