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Thursday, September 3, 2015

High Court delivers verdict on Crestor patent

By Tracy Lu, Senior Associate

In an unanimous decision, the bench of five Justices of the High Court in the litigation between AstraZeneca, Apotex, Watson and Ascent involving the drug rosuvastatin (brand name Crestor) found against the patentee on the ground of lack of inventive step having regard to the combination of common general knowledge (CGK) with either one of two pieces of section 7(3) prior art information.

We previously reported on the lower court decisions in this case in August 2014 and April 2015.

Background


The patent related to methods of treatment involving the use of particular doses or dosage ranges of a cholesterol lowering agent, rosuvastatin and its pharmaceutically acceptable salts. The invention addressed the problem of developing a new statin treatment that could bring more patients to their target blood cholesterol level without the need to resort to dose titration.

At the relevant date, section 7(2) of the Patents Act (Cth) (the Act) provided:
(2) For the purposes of this Act, an invention is to be taken to involve, 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. (emphasis added)

Section 7(3) of the Act provided:
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) [omitted as it is irrelevant for this case];
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. (emphasis added)

At first instance in the Federal Court, Justice Jagot found that:
  1. AstraZeneca was not entitled to the patent on the ground that the claimed methods were invented by employees of a third party organisation, Shionogi.
  2. The invention was invalid for:
    • (a) lack of novelty; and
    • (b) lack of inventive step, having regard to either the common general knowledge as at the priority date (the CGK) alone or in conjunction with either one of two pieces of section 7(3) prior art information, referred to as Patent 471 and the Watanabe Article.

On appeal to the Full Court of the Federal Court, a bench of five judges comprising Besanko, Foster, Nicholas, Yates and Jessup JJ found that:
  1. The primary judge erred in finding that the invention lacked novelty.
  2. The primary judge erred in finding that the invention lacked inventive step having regard to the CGK alone.
  3. However, the invention did lack inventive step having regard to the CGK in conjunction with either one of the Patent 471 or the Watanabe Article.
  4. The appeal against the primary judge's findings on entitlement failed.


Issues for determination by the High Court


AstraZeneca was subsequently granted special leave to appeal to the High Court.

The main issues for determination by the High Court were:
  1. whether section 7(2) requires that each source of information not forming part of the CGK be considered separately for the purposes of assessing whether or not that source of information satisfies the 'ascertained, understood and regarded as relevant' requirement in section 7(3);
  2. whether section 7(2) allowed the Court to decide the question using a "single avenue approach", i.e. on the basis that the only course available to the skilled person was that identified in the relevant section 7(3) document and the CGK, even though there is another section 7(3) document (in this case, another piece of prior art - the Aoki Article) which, when combined with the CGK, led the skilled person down a different avenue (in this case, another promising compound known as NK-104);
  3. whether the lack of disclosure of animal or human trial safety data in the section 7(3) documents meant that rosuvastatin would not have been tried as a matter of course in the expectation for a solution to the problem in the CGK; and
  4. whether the findings on entitlement were incorrect, in view of provisions of the Act which were introduced after the judgment date of the primary judge but which have retrospective effect.


High Court's findings


Interaction of sections 7(2) and 7(3)


With respect to AstraZeneca's arguments relating to the proper construction of sections 7(2) and 7(3), the High Court unanimously agreed with the approach adopted by Justice Jessup (with whom the other judges of the Full Court of the Federal Court agreed on this point). That is, the words 'considered separately' in section 7(2) only preclude the combination (ie 'mosaicking') of documents which satisfy the requirements of section 7(3) for the purposes of obviousness. It does not preclude a skilled person combining or comparing documents not within the CGK in order to determine whether or not a document satisfies the requirements of section 7(3). Therefore, there may be multiple section 7(3) documents (which each of the Patent 471, the Watanabe Article and the Aoki Article were) selected from a plethora of non-CGK sources of information, but under section 7(2), a single section 7(3) document is considered  in conjunction with the CGK at a time.

Specifically, the High Court Justices stated:
  • 'Section 7(2) says nothing about how the relevant requirements in s 7(3) is to be satisfied.' (French CJ, [21])
  • 'A consequence of [AstraZeneca's] argument would appear to be that if a search for prior art information reveals more than one document, none of them could qualify as relevant to the problem if identifying a single document as relevant involved a process that required disregarding all other documents.' (Kiefel J, [83])
  • '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.' (Gageler and Keane JJ, [111])
  • 'As French CJ and Kiefel J conclude, there is nothing in ss 7(2) or 7(3) which precludes the person skilled in the art from looking at more than one document (whether sequentially or comparatively or otherwise) for the purposes of determining the relevance of any single document.' (Nettle J, [120])


Single avenue approach


AstraZeneca's second argument was that it was not obvious that a skilled person, when confronted with a choice between rosuvastatin (as disclosed in the Patent 471 and the Watanabe Article) and NK-104 (as disclosed in the Aoki Article), would have chosen rosuvastatin. This was also rejected.

The High Court found that section 7(2) did not in fact impose a choice on the skilled person to make such a choice between rosuvastatin and NK-104 and does not contemplate that the skilled person would cease to pursue one solution as disclosed in one section 7(3) document because there was another solution disclosed in a different section 7(3) document. The position is best reflected by Gageler and Keane JJ's statement at [115]:
The question is not whether it would have been obvious to the skilled addressee to choose rosuvastatin over NK-104; rather, it is whether a person skilled in the art would, in light of the common general knowledge plus either the Watanabe article or the 471 patent, have been directly led as a matter of course to try rosuvastatin in the expectation that it might well produce a solution to the problem which existed in the common general knowledge.


Lack of safety data


AstraZeneca also attacked the merits of the findings of lack of inventive step on the basis that the section 7(3) documents did not disclose any safety data from the conduct of animal or human trials, even though it was accepted by one of the experts that such data would be essential to determining what dosage should be tested in clinical trials.

The High Court rejected AstraZeneca's argument – although such safety data was not disclosed, the evidence also disclosed that the animal or human trials which would generate such data would conventionally be carried out and that the carrying out of such trials fell within the concept of working towards the invention with an expectation of success.


Entitlement


Given the findings on validity, the High Court declined to make determinations in relation to the entitlement issue.


Conclusion


The decision of the High Court provides important guidance on the interpretation of sections 7(2) and 7(3) as they stood before the Raising the Bar amendments, which remain applicable to standard patents granted for applications filed between 1 April 2002 and 14 April 2013 inclusive and for applications filed before 1 April 2002.


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