In the recent decision of Mylan Health Pty Ltd v Sun Pharma ANZ Pty Ltd [2020] FCAFC 116, an enlarged bench of the Full Federal Court of Australia unanimously rejected Mylan’s appeal against Justice Nicholas’ findings that three of Mylan’s Australian Lipidil (fenofibrate) patents were invalid, and therefore could not be infringed by Sun Pharma’s proposed generic fenofibrate formulations.

In addition to providing useful guidance for pharmaceutical companies regarding the infringement of patent claims limited by a specific therapeutic purpose (e.g. “Swiss-style” claims or method of treatment claims, discussed in our recent, separate article), the appeal decision clarifies and confirms:

  • the circumstances in which a patent may be invalidated by clinical trial related information and “reasoned hypotheses” published before the priority date of a patent;
  • differences between the Australian and European approach to “Swiss-style” and purpose-limited pharmaceutical patent claims; and
  • that an invention will generally be obvious if a skilled person would be directly led to try it in the expectation that it might well produce a useful result, even if the result or outcome is not certain.

1. Mylan’s fenofibrate patents and formulations

Mylan was the licensee of the following patents relating to its fenofibrate products, which it had sold in Australia under the name “Lipidil”:

  • Patent No. 2006313711 (the 711 patent), which related to the manufacture of a medicament comprising fenofibrate to prevent/treat retinal damage arising from diabetic complications;
  • Patent No. 2003301807 (the 807 patent), which broadly related to nanoparticulate fenofibrate formulations, and the use of surface-stabiliser compounds to prevent agglomeration (clumping) of such formulations; and
  • Patent No. 731964 (the 964 patent), which provided an immediate-release, micronised fenofibrate composition

(together, the Mylan patents).

In April 2016, Mylan commenced proceedings against Sun Pharma alleging that Sun Pharma’s proposed launch of generic fenofibrate products threatened to infringe each of the Mylan patents. Sun Pharma denied infringement and argued that the patents were invalid on various grounds, including lack of novelty and lack of inventive step.

At trial, Justice Nicholas held that all three patents were invalid.

In summary, his Honour held that:

  • the 711 patent was invalid for want of novelty and inventive step, and that Mylan had not established threatened infringement;
  • the 807 patent lacked an inventive step; and
  • some claims of the 964 patent were invalid, and he was not satisfied that Mylan had established its case on threatened infringement for the other relevant (valid) claims.

2. The 711 patent – Claims limited by therapeutic purpose (diabetic retinopathy)

Claims anticipated by prior disclosure of clinical study hypotheses

ACCORD Protocol

At trial, Nicholas J held that the 711 patent was not novel in light of a protocol for a clinical trial called the ACCORD Protocol.

This Protocol contained a number of hypotheses, including that:

“a therapeutic strategy that uses a fibrate to lower triglyceride levels and raise HDL cholesterol levels in patients already receiving a statin drug for treatment of LDL cholesterol levels, will reduce the rate of development or progression of [diabetic retinopathy]…” (the Relevant Hypothesis).

Mylan submitted that the Relevant Hypothesis was nothing more than a “reasoned hypothesis”, arguing that the disclosure of a reasoned hypothesis that is yet to be evaluated does not:

  • constitute “clear and unmistakable directions” to perform the method;
  • “teach” the invention; or
  • deprive the patent of novelty as an anticipatory disclosure.[1]

They contended further that the Protocol merely taught the administration of fenofibrate for the purpose of evaluating its efficacy for the claimed therapeutic purpose, rather than making such a disclosure for the deliberate administration of fenofibrate for that purpose.

In summary, the Full Court unanimously:

  • reiterated that “prior documentary disclosure will not be anticipatory if it merely provides information at a level of generality which, while encompassing that which is claimed as the invention, nevertheless fails to identify the invention with sufficient specificity”[2];
  • clarified that even where the disclosing document is sufficiently specific, “it might not go far enough to disclose all the essential features of the invention”[3];
  • rejected Mylan’s submissions that a documentary disclosure containing a hypothesis could not be an anticipatory disclosure and thus deprive an invention of novelty;
  • confirmed that for novelty, “the question, simply put, remains: what does the prior document disclose?”[4]; and
  • stressed that validation or proof of a hypothesis was “certainly not required” to deprive an invention of novelty.[5] Nor was it necessary for a person skilled in the art to be persuaded by what is disclosed in the prior publication to work the method described in the prior publication, or to agree with any suggestions or recommendations contained in such a document.

Applying these principles, their Honours found that the ACCORD Protocol anticipated the relevant claims of the 711 patent. The Relevant Hypothesis disclosed precisely what was later claimed by the 711 patent, namely the (deliberate) administration of fenofibrate with the aim of preventing or treating diabetic retinopathy in patients in need of such treatment.

The Court also recognised that a different conclusion may have been reached under European law, which it said, unlike Australian law, treats “Swiss-style” claims and purpose-limited claims (like those the subject of the present dispute) as requiring the achievement or establishment of the claimed therapeutic effect, rather than simply the administration of the claimed drug for the purposes of the claimed therapeutic end.

Administration of fenofibrate in double-blind clinical trial could also deprive the 711 patent of novelty

At trial, Nicholas J rejected Sun Pharma’s case that the method claims of the 711 patent were also not novel having regard to two studies: the ACCORD Study and the FIELD Study, in which the claimed methods were allegedly used.

The ACCORD Study was the research proposed in the ACCORD Protocol (and to which the Relevant Hypothesis was to be tested), whilst the FIELD study was a separate research project discussed in the 711 patent specification.

The trial judge noted that Sun Pharma’s line of argument assumed that the investigators in the two studies knew that they were administering fenofibrate.

His Honour held that this was not possible, as the researchers were undertaking a double-blind clinical study, and so neither the investigator nor the patient knew whether they were receiving fenofibrate or a placebo. Sun Pharma submitted that the primary judge erred in reaching such a conclusion.

Interestingly, the Full Court said that they were “inclined to the view” that this challenge to novelty ought not to fail simply because the studies were double-blind studies.

Rather, the collective activity of administering fenofibrate or placebo to study participants in the context of a clinical trial could anticipate the claims, particularly when considered together with knowledge of the aims and methods of the clinical trials in question.

Clinical study information also rendered the 711 patent obvious

At first instance, Nicholas J found that the invention claimed in the 711 patent was obvious in light of information contained in a further clinical study called ETDRS 22.

The study reported an association between elevated serum triglyceride levels of patients and the increased risk of those patients developing retinal hard exudates. For the purposes of the 711 patent, the prevention of diabetic retinopathy included preventing the development or progression of hard exudates.[6]

The appeal court rejected Mylan’s argument that Justice Nicholas erred in his analysis of the question of inventive step. They confirmed that:

  • an assessment of inventive step involves a “tricky” evaluative judgment;
  • the assessment may be aided by asking whether a person skilled in the art would be directly led as a matter of course to try the claimed invention in the expectation that it might well produce a useful or better alternative (the so-called “reformulated Cripps question”); and
  • such an evaluative exercise does not require the Court to form a view as to whether the person skilled in the art’s expectation of success was better than “fifty-fifty” or to otherwise assess the chances of success in percentage terms.

While an outcome that is a “mere possibility” or simply “worth a try” is unlikely to be obvious, here, the evidence supported the primary judge’s findings that a person skilled in the art would consider the outcome disclosed in ETDRS 22 to be more than a mere possibility – they would have a reasonable expectation that they might well produce the claimed outcome by following the information in that prior disclosure.

3. The invention claimed in the 807 (nanoparticulate) patent was also obvious

The appeal in relation to the 807 patent also focussed on the question of inventive step.

Generally, an invention will be found to not involve an inventive step if it is obvious in light of:

  • the common general knowledge of persons skilled in the art at the priority date of the invention; or
  • the common general knowledge considered together with one (and, in certain prescribed circumstances, multiple) relevant prior art documents that do not form part of the common general knowledge.

Somewhat unusually, the primary judge found that the invention claimed in the 807 patent was obvious in view of the common general knowledge (considered alone), but not so when the common general knowledge was combined with a specific prior art document designated as the 704 patent.

Mylan’s attack on the primary judge’s findings was multifaceted and involved arguments that the primary judge had erred in making findings in relation to common general knowledge (and the obviousness of the invention in light of the common general knowledge alone), particularly in circumstances where the expert evidence (and submissions) filed by the parties on this issue was largely predicated on, and related to, the information in the 704 patent prior art, which itself was not a part of the common general knowledge.

The appeal court rejected Mylan’s arguments and held that the primary judge had a proper factual foundation upon which to base his conclusions.

In reaching this view, the Full Court also recognised the advantages the primary judge enjoyed in assessing the evidence on inventive step, including in the “dynamic process of experts giving their evidence, and exchanging their opinions, concurrently”. Their Honours acknowledged that, while they were required to make up their own minds on the question of obviousness, in doing so, they ought to give due weight to the conclusions drawn by the primary judge.

4. Relevant claims of the 964 patent travelled beyond the micronized fenofibrate invention described in the patent

Finally, the appeal in respect of the 964 patent was confined to whether the primary judge correctly held that the invention claimed in certain claims of the 964 patent “travelled beyond” and was therefore not “fairly based” on the matter described in the specification in breach of section 40 (3) of the Patents Act. This was in circumstances where the challenged claims were to a composition having a certain dissolution profile, but were not expressly limited to fenofibrate in a micronised form.

Mylan argued on appeal that Justice Nicholas improperly read down the invention with reference to the Examples in the specification, and otherwise misconstrued the broad nature of the invention described in the specification, including in its consistory clauses. The Full Court rejected Mylan’s arguments and in so doing reiterated that a consistory clause must be read in the context of the specification as a whole.

5. Conclusion and key takeaways

This decision highlights some important considerations for patent holders and challengers alike:

  • Prior art documents which contain pertinent hypotheses are capable of destroying novelty;
  • Double-blind clinical trials may also deprive an invention of its novelty;
  • Attention should therefore be given to any disclosures made prior to, or in the context of, clinical or other trials relevant to potential or actual patented technology;
  • The question of obviousness is a tricky, evaluative exercise that is normally not assisted by a percentage-based analysis; and
  • A claimed outcome may be obvious even if a person skilled in the art cannot say with certainty that the outcome will be produced by following a series of routine steps.