Last month, on 13 and 14 May 2015, the High Court of Australia heard the Appeal in the rosuvastatin case from the Full Federal Court decision (AstraZeneca AB v Apotex Pty Ltd [2014] FCAFC 99). As we reported in our article of 31 March 2015, the High Court of Australia granted AstraZeneca leave to Appeal despite the Full Federal Court sitting 5 judges (instead of the usual 3) in the Appeal from the first instance decision (Apotex Pty Ltd v AstraZeneca AB (No. 4) [2013] FCA 162).

AstraZeneca were unsuccessful both at first instance and before the Full Federal Court. Although there were originally 3 patents in suit, before the High Court only the Low Dose Patent was in suit. The Low Dose Patent has dosing regimen claims to the administration of 5 or 10 mg of rosuvastatin as a starting dose for the treatment of hypercholesterolemia. Rosuvastatin is a cholesterol lowering agent sold under the brand name CRESTOR.

The primary issue before the High Court was the correct approach for assessing whether an invention involves an inventive step (is obvious). The other issues before the High Court are not discussed in this article.

AstraZeneca's Appeal on Inventive Step

Relevant Legislation

The relevant sections of the Patents Act (1990) in relation to determining whether an invention involves an inventive step are sections 7(2) and 7(3). As they applied to the Low Dose Patent, s7(2) and s7(3) are:

7(2) For the purposes of this Act, an invention is to be taken to involve an inventive step when compared with the prior art base unless the invention would have been obvious to a person skilled in the relevant art in the light of the common general knowledge as it existed in the patent area before the priority date of the relevant claim, whether that knowledge is considered separately or together with either of the kinds of information mentioned in subsection (3), each of which must be considered separately.

7(3) For the purposes of subsection (2), the kinds of information are:

(a) prior art information made publicly available in a single document or through doing a single act; and

(b) prior art information made publicly available in 2 or more related documents, or through doing 2 or more related acts, if the relationship between the documents or acts is such that a person skilled in the relevant art in the patent area would treat them as a single source of that information;

being information that the skilled person mentioned in subsection (2) could, before the priority date of the relevant claim, be reasonably expected to have ascertained, understood and regarded as relevant to work in the relevant art in the patent area.

The ‘threshold requirement’ under s7(3)

In order to qualify as a s7(3) document the ‘threshold requirement’ must be satisfied that the prior art information is information that a skilled person could “be reasonably expected to have ascertained, understood and regarded as relevant to work in the relevant art in the patent area”.

To establish that a document satisfies the threshold requirement and is a relevant s7(3) document it is common for challengers to a patent to put on evidence of search results to determine whether an expert would have found (ascertained) the document, understood it and considered it relevant to the problem.

Once a document qualifies as a s7(3) document only the common general knowledge and the information in that single s7(3) document can be taken into consideration when assessing whether the invention is obvious under s7(2). As is clear from s7(2), as it applies to the Low Dose Patent, any section s7(3) documents must be considered separately (together with the common general knowledge) and the assessment of an inventive step under s7(2), does not allow for the combination of documents (unless under s7(3)(b) they are related such that they would be treated as a single source of information).

The question before the High Court was how the legislative framework allows for consideration of multiple s7(3) documents, each of which must be considered separately, where one of these documents leads to the invention and renders the invention obvious, whereas other documents teach away from the invention and do not render the invention obvious.

AstraZeneca’s case

AstraZeneca argued that part of their invention was the selection of rosuvastatin (as opposed to another statin) as the new statin to develop for the treatment of hypercholesterolemia. The difficulty faced by AstraZeneca was how the legislative framework for the assessment of an inventive step allows for the choice of one statin over another (when the particular statins were not part of the common general knowledge).

The evidence before the court included search results that identified a large number of documents and evidence that, having reviewed the Abstracts from 19 of these documents, the experts would have considered 3 of these documents relevant to the problem of finding a new statin with improved properties for the treatment of hypercholesterolemia. Of these documents, one of them, Watanabe, disclosed S-4522 (rosuvastatin) as a potent new statin undergoing clinical trials and another document, Aoki, disclosed an alternative statin, NK-104 (pitavastatin) as a potent new statin. Neither of these documents included information about 5 and 10 mg doses of statins.

The evidence established that each of these documents satisfied the threshold requirements and were therefore relevant s7(3) documents.

AstraZeneca were faced with the situation where the selection of Watanabe as a s7(3) document teaches towards the invention as it discloses rosuvastatin as a potent new statin, whereas the selection of Aoki as a s7(3) document teaches away from the invention as it discloses an alternative statin, pitavastatin. The legislative framework does not allow for the combination of the two documents and the skilled addressee, at the time of considering whether the invention involves an inventive step under s7(2), would never have before him both the Watanabe article and the Aoki article and so would never be faced with choosing between the two statins.

In view of the limitations of the legislative framework in dealing with multiple s7(3) documents, AstraZeneca formulated alternative submissions to challenge the finding of the lower courts of a lack of inventive step of the Low dose Patent in view of Watanabe together with common general knowledge.

Impermissible comparison between documents located in a search

One of the submissions put forward by AstraZeneca was that there was an impermissible comparison by the experts of documents located in the search in selecting the Watanabe document as the most relevant document for the assessment of inventive step.

Essentially, AstraZeneca put forward arguments that Watanabe should not have been a s7(3) document as the experts only selected it by impermissible comparisons between it and other documents located in the search.  The High Court Judges questioned whether the whittling down of search results to select relevant documents was simply a necessary part of “ascertaining” a document under s7(3). Furthermore, as submitted by the generic parties, the evidence indicated that even if the experts made comments about Watanabe being the most relevant document, that did not take away from the fact that Watanabe was nevertheless a relevant s7(3) document that satisfied the threshold requirements. The generic parties submitted that there is no requirement for the most relevant document to be selected. Finally, the judges did not appear to consider it overly relevant what the experts in fact did as the assessment of an inventive step involves considering whether a hypothetical person, armed with Watanabe and common general knowledge, would have considered the invention obvious.

Conducting a further search

A further line of argument put forward by AstraZeneca was that a skilled person, armed with their common general knowledge and Watanabe, still would have conducted a further literature search to determine whether any other statins were available that could have been developed for the treatment of hypercholesterolemia. Even though s7(2) would not allow for the combination with Watanabe of any documents found in a such search, AstraZeneca submitted that it was enough that a skilled person would conduct a search to be able to state that a skilled person would not have been directly led as a matter of course to try rosuvastatin and that the invention was therefore not obvious.

Doses not obvious

A final argument put forward by AstraZeneca was that it would not have been obvious, in view of Watanabe and the common general knowledge, to select 5 and 10 mg doses of rosuvastatin.

Summary

This case highlights the difficulties faced by patentees in defending an allegation of lack of inventive step where there are multiple s7(3) documents, one of which may teach towards the invention while others teach away from the invention.

Subsequent amendments to the Patents Act (1990) have expanded the prior art base, with a combination of documents being allowed under s7(3) since 1 April 2002, and with the raising the bar amendments to the Patents Act (1990) having removed the s7(3) threshold requirements that a document be “ascertained, understood and regarded as relevant to work in the relevant art in the patent area”. Nevertheless, the decision in this case will have significance for patents filed before 1 April 2002.

The generic parties’ case in Contention – the “starting point” issue

The other issue in relation to inventive step before the High Court, the “starting point” issue, arose from the generic parties Notice of Contention. Throughout the course of the rosuvastatin litigation, both at first instance and before the Full Federal Court, one of the main issues has been the correct “starting point” for the assessment of an inventive step and whether reference can be made to the specification and, in particular, what the patentee has described as the problem, in determining the starting point for the assessment of an inventive step. In other words, whether something that is not common general knowledge or is not contained in a s7(3) document can be taken into consideration in determining whether an invention involves an inventive step. The significance of this for the present case is whether the selection of rosuvastatin forms part of the invention.

First instance decision on “starting point”

Rosuvastatin was held not to form part of the common general knowledge in Australia at the priority date of the Low Dose Patent. Jagot J held at first instance that “the terms of the specification and claims informs the identification of the relevant starting point for the assessment of obviousness”. In relation to the Low Dose Patent, Jagot J held that “the specification identifies the invention in a manner which pre-supposes the existence of rosuvastatin”. In light of this finding, Jagot J held that the Low Dose Patent lacked an inventive step in light of the common general knowledge alone as “the invention involved nothing more than the identification of a conventional starting dose for a compound within a known class for a known purpose.”

Full Federal Court decision on “starting point”

The Full Federal Court overturned the first instance decision in relation to the starting point issue, stating that the legislation only allows for common general knowledge and any s7(3) document to be taken into consideration.

Even though the Full Federal Court reversed the first instance decision of Jagot J and held that the invention did not pre-suppose the existence of rosuvastatin, they nevertheless upheld the decision that the Low Dose Patent lacked an inventive step in light of the common general knowledge together with either Watanabe or the ‘471 Patent (both being relevant s7(3) documents).

Appeal before the High Court

The generic parties presented arguments in relation to the starting point issue discussed above and sought to have the Full Federal Court’s decision on this point overturned.

It will be interesting to see whether the High Court upholds the decision of the Full Federal Court. From the perspective of the patentee, it is of course desirable not to be limited to what is described in the specification as the invention and in this regard it would be preferable if the Full Federal Courts decision on “starting point” is upheld.

The High Court reserved its decision and we would not expect a decision until later this year.