Australia: High Court upholds finding that Crestor patent is invalid

In the much anticipated AstraZeneca AB v Apotex Pty Ltd1, the High Court of Australia unanimously upheld a decision by an enlarged Full Federal Court (that is, 5 judges rather than the usual 3), that an AstraZeneca patent relating to the blockbuster statin drug CRESTOR (rosuvastatin) is invalid. The AstraZeneca patent is directed to methods of using low doses of rosuvastatin to treat high cholesterol (the Low Dose Patent) which the High Court found lacking in inventiveness (that is, "obvious") when compared with the "prior art base".

The High Court's decision2 clarifies how expert witnesses may undertake searches to locate "prior art information" which may be taken into account when addressing the issue of inventive step and the proper treatment of this "prior art information" in the inventive step analysis.

The High Court's decision also leaves untouched the Full Court's decision on "starting point" – that is, information against which the question of inventiveness is to be determined (common general knowledge (CGK) and any relevant prior art) cannot be enlarged by reference to the description in the body of the patent specification.


  • An expert witness tasked with identifying relevant "prior art information" for the purpose of assessing inventive step is permitted to refer to and consider other pieces of "prior art information" (as well as CGK) in their search process, in order to determine which pieces of "prior art information" they consider relevant.
  • For patents filed prior to April 2002 (as the Low Dose Patent was), each piece of "prior art information" ultimately identified by an expert must be considered one at a time together with the CGK in determining whether a claimed invention contains an inventive step. If the invention is obvious in light of the CGK plus any one of the ascertained pieces of "prior art information" then the patent is invalid for lack of inventive step.
  • In industries (such as the pharmaceutical industry) where animal and human clinical studies are routinely performed, absence of animal or human safety data in a piece of "prior art information" does not mean that it cannot be used to challenge the inventiveness of a claimed treatment regimen.


At first instance, Justice Jagot found that the claims of the Low Dose Patent were invalid on three grounds. Firstly, AstraZeneca was not entitled to the Low Dose Patent. Secondly, the invention disclosed in the Low Dose Patent lacked novelty in light of two pieces of prior art – the Watanabe Article and the 471 Patent, both of which disclosed the compound rosuvastatin. Thirdly, the invention disclosed in the Low Dose Patent did not involve an inventive step.

Justice Jagot's decision was appealed to an enlarged bench of the Full Federal Court, constituted primarily to determine the key issue of the correct "starting point" for assessing inventive step.3 Although it rejected Justice Jagot's finding on the "starting point" question and held that the problem addressed in a patent specification is not necessarily part of the CGK for assessing obviousness, the Full Federal Court upheld the conclusion that the invention claimed in the Low Dose Patent was obvious, in light of the CGK plus either of the Watanabe Article and the 471 Patent. The reasoning is explained below. Justice Jagot's finding that AstraZeneca was not entitled to the Low Dose Patent was also upheld, but the other findings were overturned.

While another AstraZeneca patent (which related to particular compositions of rosuvastatin) was revoked in the first instance and Full Federal Court decisions, it was not pressed in the High Court.


On further appeal to the High Court, AstraZeneca sought to reverse the Full Federal Court's findings of obviousness and lack of entitlement. As the High Court ultimately upheld the Full Federal Court's finding of obviousness it did not consider the entitlement issue.

Argument in the High Court appeal centred on the construction of the words of section 7(2) and 7(3) of the Patents Act 1990 (Cth) (the Act), with the High Court ultimately holding that the positions put forward by AstraZeneca were "constructions of ss 7(2) and 7(3) which their text will not bear".4


In order to be patentable, under section 18(1)(b)(ii) of the Act, a claimed invention must involve an inventive step when compared with the "prior art base" as it existed before the priority date of the claim.

The test for determining inventive step is set out in section 7(2) of the Act (emphasis added):

" 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."

Section 7(3)(a) further provided:

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

(a) prior art information made publicly available in a single document ...

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 parties' arguments related to whether "prior art information" must be "considered separately" at both stages of the inquiry, that is, when searching for relevant "prior art information" and when assessing inventive step.


  1. Undertaking searches - the threshold "relevance requirement"

First, AstraZeneca argued that the phrase "considered separately" in section 7(2) required "prior art information" in a non-CGK source to be reviewed in isolation from other non-CGK sources in undertaking searches, that is, to determine whether the source of information satisfies the threshold "regarded as relevant" requirement in section 7(3). On AstraZeneca's view, the approach taken by the expert witnesses in this case5 - to perform a literature search and then compare the documents which resulted from the search to determine which they considered most relevant - was not allowed.

The High Court rejected AstraZeneca's argument and affirmed the approach taken by Justice Jessup in the Full Federal Court. Specifically, the High Court held that while the phrase "considered separately" prevents the use of a combination of unrelated documents ("mosaicking") to defeat the inventiveness of a claimed invention under section 7(2), it did not restrict how the threshold "regarded as relevant" requirement in section 7(3) is satisfied.

  1. Using prior art information - assessing inventive step

Second, AstraZeneca submitted that the Full Federal Court had applied the test for inventive step in section 7(2) incorrectly by considering each piece of "prior art information" in isolation. AstraZeneca argued that this approach suggested that the "only course available to the skilled person [was] that identified in the s 7(3) document [a]dded to the prior art base" and allowed the expert to ignore potential "false" avenues to solve the problem suggested by other relevant documents; an approach fundamentally affected by hindsight.6 AstraZeneca argued that in reality, the skilled person would have been confronted with a number of choices of compounds and therefore the choice of rosuvastatin was not obvious.

In support of its argument, AstraZeneca referred to an additional document (the Aoki Article) located by the expert witnesses, which identified the compound, NK-104, as a promising cholesterol lowering agent. AstraZeneca argued that once NK-104 was identified, the skilled person would be confronted with a choice as to whether NK-104 or rosuvastatin should be selected and that there was an evidentiary gap in this regard.

Chief Justice French rejected AstraZeneca's argument on the basis that the words of section 7(2) simply did not support such a construction; once identified as relevant in accordance with section 7(3), each piece of "prior art information" must be considered on its own, with the CGK. In any case, Justice Kiefel noted that there was evidence that a skilled addressee would have selected rosuvastatin over NK-104.


In determining whether the invention claimed in the Low Dose Patent was obvious or not, the High Court adopted the 'reformulated Cripps question' considered by Justice Jessup, namely7:

"whether the notional skilled person would have directly been led as a matter of course to try the invention as claimed in the expectation that it might well produce a better method of treating a patient suffering from hypercholesterolemia than existing statins and doses."

The High Court agreed with Justice Jessup's view that the effect of the expert evidence was that a person skilled in the art, having read the Watanabe Article in light of the CGK would have entertained the expectation that rosuvastatin might well be at least as efficacious a treatment as atorvastatin (the leading treatment at the time). It would then have been a routine step to test rosuvastatin at the lowest efficacious dose as part of conventional clinical trial procedure.8 Accordingly, the absence of animal or human trial safety data (which would be useful in determining doses that should be tested in clinical trials) in the Watanabe Article and 471 Patent did not prevent a conclusion that the invention claimed in the Low Dose Patent lacked inventiveness.


The High Court has clarified the approach that may be taken by the hypothetical skilled addressee to identify relevant "prior art information" for the purpose of assessing inventive step.

In the words of Justices Gageler and Keane9:

"Nothing in s 7(3) suggests that the notional skilled addressee may not trawl through multiple documents, discarding the irrelevant and retaining the useful, as part of the ascertainment of relevant information."

In addition, the decision highlights that when considering the question as to whether an invention is obvious in light of the CGK and "prior art information", the skilled person must consider each piece of prior art separately. This is the case even where there may be a number of pieces of prior art, some of which propose different solutions to the problem.

It is important to note that the priority date of the Low Dose Patent was 6 February 1999. Since then amendments have been made to section 7(3) of the Act which permit certain combinations of prior art documents when determining inventiveness. Similarly, the amendments introduced by the Raising the Bar Act10 mean that it is no longer necessary to establish that prior art would have been "ascertained, understood and regarded as relevant" by the skilled person.


1 AstraZeneca AB v Apotex Pty Ltd; AstraZeneca AB v Watson Pharma Pty Ltd; AstraZeneca AB v Ascent Pharma Pty Ltd [2015] HCA 30 (the High Court Appeal).

2 Each High Court judge (with the exception of Justices Gageler and Keane) delivered separate judgments.

3 Our earlier IP Preview Article discussed the Full Federal Court decision in detail.

4 High Court Appeal at [8].

5 The expert evidence relevant to inventive step was that of Professor O'Brien and Dr Reece, both of whom were experts for the generic parties.

6 High Court Appeal at [24].

7 High Court Appeal at [40].

8 See also High Court Appeal at [80].

9 High Court Appeal at [111].

10 Intellectual Property Laws Amendment (Raising the Bar) Act 2012 (Cth)

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.

Most awarded firm and Australian deal of the year
Australasian Legal Business Awards
Employer of Choice for Women
Equal Opportunity for Women
in the Workplace (EOWA)

To print this article, all you need is to be registered on

Click to Login as an existing user or Register so you can print this article.

Some comments from our readers…
“The articles are extremely timely and highly applicable”
“I often find critical information not available elsewhere”
“As in-house counsel, Mondaq’s service is of great value”

Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at and we will use commercially reasonable efforts to determine and correct the problem promptly.