What you need to know
- In December 2017, the Full Court of the Federal Court of Australia upheld the first instance decision of Justice Jagot, and held that Gilead had successfully invalidated Idenix’s patent (the Idenix Patent) for compounds for the treatment of flaviviridae infections (including hepatitis C virus (HCV)) on the grounds on insufficiency and inutility.
- Gilead manufactures and sells its sofosbuvir containing drug Solvadi®. Solvadi®, which has been heralded as a cure for certain types of HCV, is currently the second most subsidised drug on Australia’s Pharmaceutical Benefits Scheme (PBS), receiving billions of dollars in Government subsidies since its inclusion on the PBS in 2016.
- In March 2016, Gilead successfully invalidated the Idenix Patent on the grounds of insufficiency and inutility (Gilead Sciences Pty Ltd v Idenix Pharmaceuticals LLC [2016] FCA 169). The owners of the Idenix Patent, Idenix Pharmaceuticals LLC, Università degli studi di Cagliari, Centre national de la recherche scientifique and Université De Montpellier (together, Idenix) appealed Justice Jagot’s first instance decision, alleging that the Primary Judge erred in her conclusions on insufficiency, fair basis and inutility. Gilead filed a notice of contention, submitting that the Idenix Patent should also be invalid for lack of novelty, and that her Honour erred on aspects of her fair basis analysis.
- In the Full Court, Justices Nicholas, Beach and Burley dismissed Idenix’s appeal and rejected Gilead’s grounds of contention. The Full Court upheld her Honour’s findings that the Idenix Patent:
- lacked utility, as it disclosed compounds which could not, in fact, be synthesised, and
- was insufficient, as it failed to disclose sufficient information to enable the skilled team to synthesise a compound falling within claim 7 without new invention or prolonged study of matters presenting initial difficulty.
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- In a separate decision (Idenix Pharmaceuticals LLC v Gilead Sciences Pty Ltd (No 2) [2018] FCAFC 7), the Full Court ordered Idenix pay 90% of Gilead’s costs in the appeal, including the notice of contention.
- Idenix has filed an application for special leave to appeal the Full Court’s decision on invalidity to the High Court of Australia.
What you need to do
- When seeking to revoke a patent for lack of sufficiency, proof of the inventor’s own repeated and prolonged failures to make something within a claim can be powerful evidence of insufficiency. In this case, the fact that Idenix’s specialised internal team spent numerous years repeatedly failing to make a compound within claim 7 of the Idenix Patent was material to the Court’s findings on insufficiency.
- To prove that information is common general knowledge it must be generally accepted without question by those in the art as forming part of the “background knowledge and experience which is available to all in the trade”. It is not enough that information is found in a journal, even if widely read. In this case, the route of synthesis which Idenix failed to prove as CGK was considered “unlikely to work” at the relevant date by Gilead’s experts, and only known to Idenix’s experts through their work on specific projects and reading of noncommon general knowledge publications.
- Although proving lack of inutility in pharmaceutical cases is often challenging, the Full Court has confirmed that there is no requirement to prove utility by experiment. The relevant standard for assessing utility is the balance of probabilities, and absolute scientific proof is not required.
Background
The Idenix Patent (Australian Patent No. 200327084 entitled “Modified 2’ and 3’-nucleoside prodrugs for treating flaviviridae infections”) relates to compounds for the treatment of flaviviridae infections, including the HCV infection. The Idenix Patent covered trillions of compounds, including sofosbuvir. Gilead also owned a patent which disclosed sufosbuvir (the Clark Patent).
In 2013, Gilead commenced revocation proceedings alleging that the Idenix Patent was invalid on the grounds of lack of manner of manufacture, lack of novelty, lack of fair basis, inutility, insufficiency and false suggestion. Gilead admitted that its Solvadi® product would infringe claims 7, 8, 10 and 13 of the Idenix Patent, if the patent was valid.
At first instance, Justice Jagot held that the Idenix Patent was invalid for failing to meet the utility and sufficiency requirements under sections 18(1)(c) and 40(2)(a) of the Patents Act 1990 (Cth) (the Act), as it stood before the commencement of the “Raising the Bar” amendments.
Sufficiency: DAST route not CGK
The Primary Judge held that claims 7 to 41 of the Idenix patent did not comply with section 40(2)(a) of the Act and were invalid for insufficiency.
Justice Jagot had accepted Gilead’s arguments that the Idenix Patent lacked sufficiency, as the specification did not fully describe how to synthesise certain compounds covered by claim 7. Specifically, Gilead had contended that the Idenix Patent specification did not describe how to introduce fluorine into a nucleoside at the 2’ down position of the sugar ring and a carbon-containing group (such as a methyl, CH3, group) at the 2’ up position on that ring, when compounds with that chemical substitution fell within claim 7. Gilead claimed that the chemistry required to synthesise such a compound (the “target compound”) was not routine
at the priority date, and involved “new invention, addition or a prolonged study of matters presenting initial difficulty”.
"Just DAST it"
Idenix accepted that the Idenix Patent did not give the skilled addressee any express method for producing the target compound. However, Idenix contended that when armed with the Idenix Patent and common general knowledge (CGK), the target compound could be synthesised using a route of synthesis called “DAST”. Broadly speaking, the “DAST” route involved reacting a precursor compound with diethylaminosulfur trifluoride (DAST), or Deoxo-Fluor (a DAST analogue that functioned in a similar way). At trial, this was referred to by Gilead as Idenix’s “Just DAST-it” approach.
At first instance, a significant volume of Idenix’s internal documents which recorded Idenix’s own attempts, and subsequent failures, to make a compound within claim 7 of the Idenix Patent were admitted as evidence. Justice Jagot considered that these documents provided a “very strong basis” and “powerful evidence” of the insufficiency of the Idenix Patent.
Findings
The Full Court found there was “clear and compelling evidence” before Justice Jagot to justify her findings on insufficiency. Significantly, the Full Court found that:
- The Idenix Patent not only failed to disclose a means of synthesising the target compound, it disclosed routes of synthesis which taught away from the appropriate methods by providing a method with the wrong stereochemistry to enable the production of a claim 7 compound.
- Idenix had failed to prove that the DAST route was CGK, or disclosed in the Idenix Patent. A statement in the Idenix Patent specification that claimed compounds could “be synthesized by any means known in the art” was inadequate to prove that the Idenix Patent disclosed the DAST route, or that the DAST route was CGK. The Court noted that “known” is not co-extensive with CGK. In this case, the weight of expert evidence indicated that the DAST route was not part of the “background knowledge and experience” of those working in the field. There was no error in Justice Jagot’s preference of the evidence of Gilead’s experts, who considered that at the relevant date, the DAST route was complex and uncertain chemistry, and would have thought it was unlikely to work even if the skilled team had attempted to use it to synthesize a claim 7 compound.
- The failures recorded in the Idenix documents were material to the question of insufficiency. The Idenix scientists were unable to produce an embodiment of a compound falling within claim 7, despite having a team of scientists and consultants engaged on the task for more than three years, and a supposed sufficient description of that invention at hand in the Idenix Patent.
The Full Court was also critical of Idenix’s “overly elaborate” strategy on appeal. Their Honours considered that Idenix’s grounds of appeal were designed to require the Full Court to “conduct a re-trial of the complex factual questions litigated before her Honour”. The Court noted that this would have required Idenix to demonstrate that Justice Jagot’s evidentiary findings were “glaringly improbable” or shown to be wrong by “incontrovertible facts”. Not only did the Full Court consider that Idenix failed to come anywhere near to satisfying this threshold, their Honours’ reasons are littered with judicial chastisement for Idenix’s attempt to use the appeal to simply “put the dice into the box for another throw”.
Inutility: not all compounds could be made
Idenix also challenged Justice Jagot’s findings at first instance that claim 7 of the Idenix Patent lacked utility as the claim covered compounds which could not be made. Her Honour accepted Gilead’s submission that the “promise” of claim 7, was that compounds with a bromine of iodine at Y3 position in the formula in claim 7 could be made.
Idenix challenged this finding, alleging that Gilead had failed to prove by experimental evidence that compounds within claim 7 within a bromine or iodine at the Y3 position could not be made. However, the Full Court found that Justice Jagot had not erred in accepting that the weight of expert evidence (including evidence from Gilead’s experts and Idenix’s expert under cross-examination) indicated, on the balance of probabilities, that there were compounds within claim 7 that could not be made. Significantly, the Full Court observed that “[t]here is no requirement to prove inutility by experiment”.
Other grounds
As noted above, the Full Court also dismissed Gilead’s notice of contention, which had challenged Justice Jagot’s findings on novelty, lack of external and internal fair basis. The Full Court upheld Justice Jagot’s findings that the Idenix Patent was entitled to a priority date which was earlier than the priority date of Gilead’s own patent, the Clark Patent. Thus the Clark Patent did not deprive the Idenix Patent of novelty. The Full Court also concurred with her Honour’s conclusion that the Idenix Patent was not invalid for lack of fair basis as, contrary to Gilead’s submission, embodiments within the specification matched or mirrored claims 7, 8 and 9 of the Idenix Patent.
Costs
In a separate decision, the Full Court ordered Idenix pay 90% of Gilead’s costs of and incidental to the appeal, including the notice of contention. Idenix had sought to reduce its costs liability by 30% on the basis that a significant amount of time and effort was involved in dealing with Gilead’s notice of contention. However, the Full Court considered that the length and complexity of the appeal was primarily dictated by Idenix’s grounds of appeal and considered that a 10% reduction was a fair representation of the relative significance of Gilead’s notice of contention on hearing time.
Authors: Peter Chalk, Partner; and Colette Downie, Lawyer.
