A clinically-reasoned hypothesis can invalidate an Australian Pharmaceutical Patent

Identifying new uses to existing drugs is not uncommon. In fact, repurposing existing drugs to treat disorders other than its initially-approved indication holds real potential in providing patients options when access to other effective treatments is unavailable. When a drug is repurposed, its safety profile, side effects and drug interactions are well understood, which enables medical practitioners to make better-informed decisions for a patient’s treatment regime.

Pharmaceutical industries can protect a newly discovered use of an existing drug using second medical use claims, such as ‘Swiss-style’ claims and/or method of treatment claims, in Australia. In the recent decision of Mylan Health Pty Ltd v Sun Pharma ANZ Pty Ltd [2020] FCAFC 116, the Full Federal Court (FFC) establishes significant findings with respect to when a pharmaceutical patent claiming a second medical use for an existing drug may be invalidated by a clinically-reasoned hypothesis of a clinical trial.

sheet of pills, pharmaceuticals


In brief, Mylan sold fenofibrate products under the brand name Lipidil for treating Diabetic Retinopathy since 2015. Mylan’s Australian patent No. 2006313711 (711 Patent) was a second medical use patent directed to the use of fenofibrate or a derivative thereof for preventing and/or treating Diabetic Retinopathy. Sun Pharma wanted to market a number of generic fenofibrate products under the brand names FENOFIBRATE RBX, FENOFIBRATE SUN and FENOFIBRATE RAN (Ranbaxy Products) in Australia and entered the ARTG in 2016.

Sun Pharma initially listed the Ranbaxy products on the ARTG for the reduction in the progression of Diabetic Retinopathy in patients with type 2 diabetes and existing Diabetic Retinopathy, which were the same indications as for Lipidil, but later amended it to be indicated as an adjunct to diet in the treatment of hypercholesterolaemia, and various types of dyslipidaemia, including that associated with type 2 diabetes and also stated it to be a bioequivalent to Lipidil.

Mylan sought injunctive relief restraining Sun Pharma from marketing the generic fenofibrate products in Australia and thereby potentially infringing certain claims of Mylan’s 711 Patent.

Primary Judgement

In the primary proceeding (Mylan Health Pty Ltd v Sun Pharma ANZ Pty Ltd [2019] FCA 28), Nicholas J held that the relevant claims of Mylan’s 711 Patent lacked novelty in view of a clinical trial protocol, which was part of the ACCORD (The Action to Control Cardiovascular Risk in Diabetes) clinical trial, referred to as the ACCORD Protocol that was publicly available before the priority date of the relevant claims.

Among several hypotheses, the ACCORD protocol also hypothesized that:

In the context of good glycaemic control, 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 DR [Diabetic Retinopathy] compared to a strategy that only uses a statin drug for treatment of LDL cholesterol levels.” (at [48])

Mylan argued that a ‘reasoned hypothesis’ pending evaluation cannot deprive the 711 Patent claims of novelty as an anticipatory disclosure because it advanced nothing more than a ‘reasoned hypothesis’ for treatment and was not a method of treatment itself. Mylan indicated that the ACCORD Protocol merely taught the administration of a compound (fenofibrate) for the purpose of evaluating its safety and efficacy for a claimed therapeutic purpose (treating Diabetic Retinopathy), rather than making a disclosure of the deliberate administration of the compound for the purpose, aim or object of the claimed therapy (at [67]). Therefore, the unevaluated ‘reasoned hypothesis’ did not constitute a “clear and unmistakable direction” to perform the claimed method.

However, the primary judge disagreed with Mylan’s arguments and held that the relevant claims were invalid in view of the ACCORD protocol disclosure. Mylan appealed this decision to the Full Court.

Full Court Judgement

An enlarged bench of the FFC unanimously agreed with the primary decision and held that “by proposing the study, according to the Protocol and its hypothesis, there was a disclosure that fenofibrate was to be deliberately administered with a statin with the aim of preventing or treating diabetic retinopathy in patients in need of such treatment …. (and) Nothing additional was required in order for the Protocol to function as an anticipatory disclosure.” (at [105])

The FFC affirmed 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, never the less fails to identify the invention with sufficient specificity.” (at [83])

In regards to the question of novelty, the FFC indicated “the question, simply put, remains: what does the prior document disclose?  The occasion on which, or the context in which, a particular documentary disclosure is made may well inform the interpretation of the document’s content.  But if, as a matter of interpretation, the document nonetheless discloses that which is later claimed as an invention, that disclosure will anticipate the invention and deprive it of novelty.” (at [104])

In the judgement, the FFC states that the validation of the ACCORD Protocol’s hypothesis was not required to deprive the 711 Patent claims of its novelty.


The FFC affirmed that ‘reasoned hypothesis’ of clinical trial studies that are publicly available prior to the priority date of the relevant patent can deprive it of its novelty even if the ‘reasoned hypothesis’ is yet to be validated. It must be noted that these principles are different to those developed in other jurisdictions such as Europe where novelty of Swiss type claims and purpose-limited product claims will not be destroyed merely by a prior disclosure that a pharmaceutical compound might have the therapeutic effect that the patent in suit claims for that compound. Furthermore, Mylan’s request for special leave to appeal the decision of the FFC was rejected by the High Court of Australia Special Leave Dispositions (Mylan Health Pty Ltd & Anor v Sun Pharma ANZ Pty Ltd (Formerly Ranbaxy Australia Pty Ltd) & Anor [2020] HCASL 234). Therefore, this decision has severe practical implications for Pharmaceutical patentees in Australia. This decision confirms that there is a greater need to ensure that information related to clinical trial protocols should be kept strictly confidential to prevent secondary medical use patents from being invalidated due to prior anticipation by the clinical trial details being made publicly available prior to the filing of the patent.