Generic Partners & Apotex Infringe valid Neurim Sleep Patent

Neurim Pharmaceuticals (1991) Ltd v Generic Partners Pty Ltd (No 5) [2024] FCA 360 (fedcourt.gov.au)

Date of decision: 12 April 2024

Body: Federal Court of Australia

Adjudicator: Justice Nicholas

12 April 2024

Federal Court of Australia

Justice Nicholas

Neurim Pharmaceuticals (1991) Limited (Neurim) has succeeded in its enforcement action against Generic Partners and Apotex on its AU patent 2002326114 for treating ‘primary insomnia charactered by non-restorative sleep’ (the Patent). The Patent includes method of treatment claims and Swiss-style claims relating to the treatment of ‘primary insomnia charactered by non-restorative sleep’, using a prolonged-release melatonin formulation.

Neurim alleged that Generic Partners and Apotex infringed the Patent by supplying a generic version, Melotin®, of Neurim’s melatonin product Circadin®.  Generic Partners and Apotex cross-claimed, seeking to invalidate the Patent on various grounds, including clarity, novelty, inventive step and lack of fair basis.

Ultimately, Nicholas J found the patent valid and infringed.  His Honour held that Generic Partners’ and Apotex’s supply of Melotin infringed specific method of treatment claims (pursuant to section 117(2)(b)) and by authorisation of medical practitioners prescribing it as a treatment for primary insomnia characterised by non-restorative sleep in patients aged 55 and over.  Justice Nicholas also found that Generic Partners and Apotex were jointly liable for infringement because that they were at all relevant times acting in concert and pursuant to a common design to supply Melotin in Australia.

His Honour was not persuaded that any claim of the Patent was invalid.

Justice Nicholas’ lengthy judgment contains important lessons for both patentees seeking to enforce patents and parties seeking to defend such actions via a cross-claim for invalidity.  Justice Nicholas’ decision reinforces the importance of patentees deploying different strategies in enforcement proceedings; and the potential pitfalls facing a respondent relying on evidence of a hypothetical research task to establish obviousness.

Generic Partners and Apotex appealed his Honour’s decision on 7 June 2024 but the appeal was subsequently dismissed by consent on 5 August 2024 after the parties agreed to settle the proceeding on confidential terms.

Key Issues

Validity – Novelty

On novelty, Generic Partners and Apotex contended that the Patent amounted to a mere parametrisation of the prior art, claiming a narrower use of an old product that fits within the broader use for the old product already disclosed.  In support of this, Generic Partners and Apotex cited four examples of prior art uses and publications, including the sale of melatonin in the United States prior to 2001 and three prior art publications relating to the use of melatonin for various sleep disorders.  Generic Partners and Apotex argued that the cited prior art each disclosed a treatment of primary insomnia, however characterised – and so the overlaying of the additional parameter ‘characterised by non-restorative sleep’ and ‘improvement in the restorative quality of sleep’ constituted an attempt to patent a narrowed selection of the prior art.

Relying on Bennett J in Austal Ships Pty Ltd v Stena Rederi Aktiebolag (2005) 66 IPR 420 at [108], Nicholas J observed that parametrisation will not arise where “the parameters have been carefully chosen, are part of the invention, and are related to a claimed advantage as part of the combination of the design”.  Following this, his Honour found that the prior art described melatonin as a known chronobiotic for use to improve insomnia secondary to a circadian rhythm disorder.  (Chronobiotics are agents which are able to shift the endogenous circadian phase.)  In contrast, the prior art  did not address the ‘new and surprising’ result that melatonin could be used to improve the ‘restorative quality of sleep’ in a specific sub-set of insomnia patients.  Thus, Nicholas J concluded that the claims were directed to a new therapeutic use and that it was not an inevitable result of the prior use of melatonin that it had been or would be used as a treatment of primary insomnia characterised by non-restorative sleep.

In relation to the prior art publications, consisting of a webpage, journal article and prior art patent, Nicholas J held that:

• The webpage did not convey or disclose any clear direction, recommendation or suggestion to use melatonin to treat a patient diagnosed with primary insomnia characterised by non-restorative sleep, or a patient diagnosed with any form of primary insomnia. His Honour was also not convinced that he should infer that any individual used melatonin to treat primary insomnia before the priority date, noting that Generic Partners and Apotex did not lead any evidence of any actual use of the medication by patients diagnosed with insomnia.
• The journal article did not provide any clear direction, recommendation or suggestion to use prolonged release melatonin to treat primary insomnia characterised by non-restorative sleep and to improve the patient’s restorative quality of sleep.
• The patent did not convey any clear direction, recommendation or suggestion to use melatonin to treat insomnia, or primary insomnia or primary insomnia characterised by non-restorative sleep.

Validity – Inventive Step

Generic Partners’ and Apotex’s obviousness case relied on the common general knowledge and s7(3) documents consisting of four journal articles between 1995 and 2000.  To prove that the skilled addressee could reasonably be expected to have ascertained each of the s7(3) documents, Generic Partners and Apotex relied on the expert evidence of Professor Wheatley concerning a hypothetical research task undertaken with the assistance of a researcher.  Of the 45 literature records produced as part of this hypothetical research task, Professor Wheatley identified 12 of those as relevant which included three of the four cited s7(3) documents.  Professor Wheatley also observed that he would have obtained a full copy of the remaining document as it was referred to in one of the other s7(3) documents.

Nicholas J found that, while a person skilled in the art would have ascertained the s7(3) documents, they would not have considered them relevant as they did not suggest that melatonin may improve the restorative quality of a patient’s sleep – individually or as a combination. Nicholas J’s ruling underscores the difficulties faced by respondents in making out the key elements in s 7(3) (ascertainment, understanding and relevance) required to be able to rely on prior art documents (which do not form part of the common general knowledge) for the purpose of an obviousness attack.

Professor Wheatley was also asked what treatments he would have prescribed as at the priority date for an insomnia patient who:

(1)  had no underlying condition that causes the insomnia; and
(2)  complained of day time fatigue and/or not feeling rested after sleep.

Professor Wheatley initially identified a myriad of existing treatments he would have prescribed – but noted melatonin as an option only after being asked a follow-up question as to whether there were any additional treatments he would have considered prescribing if available.

Nicholas J was critical of the hypothetical research task, specifically noting that Professor Wheatley had been aware for some years that melatonin had been approved in Australia (post the priority date).  His Honour observed at [418]:

This is a common problem in cases where the invention becomes well-known to persons skilled in the art after the priority date. In that respect, to the extent that Professor Wheatley’s evidence is affected by hindsight, it is difficult to see how that problem could have been avoided.  But the fact that the problem of hindsight could not be avoided does not mean that it can be ignored and, in this particular case, it diminishes considerably the weight which I give to Professor Wheatley’s evidence as to what he would have done if asked to address the Task at the priority date.

Further, his Honour found that Professor Wheatley was steered towards melatonin as a starting point, having been directed to ‘new drugs’, which his Honour took to mean drugs that had not been approved in Australia at the priority date.  On this basis, his Honour was not persuaded that a person skilled in the art would have adopted melatonin as a starting point. Consequently, Generic Partners’ and Apotex’s submissions as to inventive step failed.

Infringement – s 117(2)(b)

Neurim alleged that Generic Partners and Apotex infringed the method of treatment claims pursuant to section 117. Section 117 provides that, in specified circumstances, if the use of a product by a person would infringe a patent, then the supply of that product by one person to another is an infringement of the patent by the supplier unless the supplier is the patentee or licensee of the patent.

One of the specified circumstances is if the supplier had reason to believe that the person would put the product to that use and the product is not a staple commercial product (s 117(2)(b)).

Generic Partners and Apotex argued that melatonin was a ‘staple commercial product’, that is, a product supplied commercially for a substantial non-infringing use or uses.  Generic Partners and Apotex argued:

(i)  First, citing Hayne J’s observations in the High Court decision of Collins, that the statutory words should not be given a narrow meaning as they are used within a provision that confers liability upon a supplier of a product where the act of supply could not otherwise constitute an infringement.

(ii)  Secondly, that it is the variety of uses for which that product can be, and in fact is supplied commercially, that will determine whether the product is a staple commercial product.

Nicholas J rejected Generic Partners’ and Apotex’s  submissions, finding that it was not relevant whether the product has non-infringing uses, but whether it is a staple commercial product.  His Honour distinguished Collins, observing that the product in that case was a species of timber commonly used for a wide variety of purposes. In contrast, his Honour determined that “melatonin’s principal, if not sole, use is as a therapeutic treatment for sleep disorders of various kinds”.  Nicholas J pointed out that the facts in this case more closely resembled that of Otsuka Pharmaceutical Co., Ltd v Generic Health Pty Ltd (No 4) (2015) 113 IPR 191 in which Yates J found that an antipsychotic (aripiprazole) was not a staple commercial product, despite it having both infringing and non-infringing uses.

On ‘reason to believe’, Nicholas J found that although melatonin was used to treat a variety of sleep disorders, Circadin was approved for use by the TGA with the approved indication only – and that the TGA approval obtained for Melotin was for precisely the same indication.  His Honour held that a reasonable person engaged in the supply of a medication approved by the TGA for use in the treatment of insomnia characterised by poor quality sleep would have reason to believe that the medication would be prescribed by a not insignificant number of psychiatrists as a treatment for primary insomnia where the patients complaint was one of non-restorative sleep.

Accordingly, Nicholas J held that Neurim’s infringement case based on section 117(2)(b) succeeded.

Infringement – s 117(2)(c)

Section 117(2)(c) captures the use of the product in accordance with any instructions for the use of the product, or any inducement to use the product, given to the person by the supplier or contained in an advertisement published by or with the authority of the supplier.

The relevant question considered here was whether the Generic Partners/Apotex Product Information Sheet (PI) for Melotin constituted an instruction or inducement to use it as a treatment for primary insomnia characterised by non-restorative sleep. The PI set out the approved indication: “[m]onotherapy for the short term treatment of primary insomnia characterized by poor quality of sleep in patients who are aged 55 or over”.

Notably, the PI did not contain any reference to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders which was first published in 1994 by the American Psychiatric Association (DSM-IV) or non-restorative sleep.  As such, in the absence of this reference, Nicholas J rejected Nerium’s submission that general practitioners or sleep physicians would have considered the reference to ‘poor quality of sleep’ as equivalent to non-restorative sleep, finding that the former relates to a broader spectrum of sleep variables, including sleep duration and latency.

Further, while Nicholas J accepted expert evidence that indicated a particular cohort of psychiatrists would have interpreted the PI in accordance with the DSM-IV, and thus, equated ‘poor quality of sleep’ with ‘non-restorative sleep’, it was ultimately determined that the PI could not be said to provide the relevant instruction or inducement.

Accordingly, Nicholas J held that Neurim’s infringement case based on section 117(2)(c) failed.

Infringement – Swiss-style Claims

Each of the Swiss-style claims were for use of melatonin in the “manufacture of a medicament for treating a patient suffering from primary insomnia characterised by non-restorative sleep”.  Following the Full Court decision in Mylan Health Pty Ltd v Sun Pharma ANZ Pty Ltd (2020) 279 FCR 354 at [222], Nicholas J observed that “infringement of a Swiss type claim is concerned with what the allegedly infringing manufacturer has done, not what it intended to do”, and that the most important consideration in making this determination are the physical characteristics of the product – its packaging, dosage and production information.

His Honour observed that the bioequivalence of Melotin to Circadin was not determinative, and that more significance was to be placed on the PI and approved indication. Nicholas J reiterated the reasoning provided in respect of s 117(2)(c) – that ‘poor quality of sleep’ has a broader meaning than ‘non-restorative sleep’ and that Melotin does not contain a relevant instruction or inducement.

Ultimately, while his Honour accepted that it was reasonably foreseeable that Melotin would be used by some clinicians for the therapeutic purpose specified in the Swiss-style claims, it was also reasonably foreseeable (and highly likely) that Melotin would primarily be used for other therapeutic purposes related to its hypnotic effects and regulation of circadian rhythms.  Thus, his Honour found no infringement of the Swiss-style claims.

Infringement – Authorisation

Generic Partners and Apotex admitted that they authorised medical practitioners to prescribe Melotin for the approved indication, however, denied that this meant that they had infringed the Patent.  Generic Partners and Apotex  submitted that “[w]ithout an instruction or inducement to use the product for the claimed purpose, there is no basis on which to conclude that such use was sanctioned, authorised [or] countenanced.”

Nicholas J rejected this argument, finding that despite the requirements of s 117(2)(c) not being met, Generic Partners and Apotex authorised the use of Melotin by medical practitioners whom they had reason to believe would use it as a treatment for primary insomnia characterised by non-restorative sleep and to improve the restorative quality of sleep in patients aged 55 and over.

Outcome

Ultimately, Nicholas J found that Generic Partners’ and Apotex’s supply of Melotin infringed specific method of treatment claims (pursuant to section 117(2)(b)) and by authorisation of medical practitioners prescribing it as a treatment for primary insomnia characterised by non-restorative sleep in patients aged 55 and over.  Justice Nicholas also found that Generic Partners and Apotex were jointly liable for infringement because they were at all relevant times acting in concert and pursuant to a common design to supply Melotin in Australia.

His Honour was not persuaded that any claim of the Patent was invalid.

Implications

Justice Nicholas’ lengthy judgment contains important lessons for both patentees seeking to enforce their patents and parties seeking to defend such actions via a cross-claim for invalidity.

On the enforcement side, Justice Nicholas’ decision illustrates clearly the importance of:

• different drafting strategies such as method of treatment claims and Swiss claims. Here, Neurim succeeded on its infringement claim based on the method of treatment claims but not the Swiss claims; and
• adopting different premises for the enforcement action. Here, Neurim’s infringement claim based on the method of treatment claims succeeded pursuant to s 117(2)(b) (but not s 117(2)(c)) and based on authorisation.  On authorisation, Nicholas J held that direct sanctioning of the claimed method is not necessary to prove infringement.  It was sufficient that authorising a broader scope of therapeutic uses which nonetheless encompasses the claimed method, will be sufficient to find infringement by authorisation.

On invalidity, Justice Nicholas’ judgment reinforces again the difficulties and pitfalls facing a respondent seeking to rely on evidence of a hypothetical research task to argue that the claimed invention is obvious.  These difficulties and pitfalls mean that Judges regularly give little weight to such evidence.

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