Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth

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FEDERAL COURT OF AUSTRALIA

Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth [2011] FCAFC 132

Citation: Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth [2011] FCAFC 132
Appeal from: Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth [2010] FCA 1211
Parties:

SIGMA PHARMACEUTICALS (AUSTRALIA) PTY LIMITED ACN 004 118 594 v WYETH AND WYETH AUSTRALIA PTY LIMITED ACN 000 296 211

ALPHAPHARM PTY LIMITED ACN 002 359 739
v WYETH AND WYETH AUSTRALIA PTY LIMITED ACN 000 296 211

GENERIC HEALTH PTY LTD ACN 110 617 859
v WYETH AND WYETH AUSTRALIA PTY LIMITED ACN 000 296 211

File numbers: NSD 1533 of 2010
NSD 1603 of 2010
NSD 1644 of 2010
Judges: BENNETT, NICHOLAS AND YATES JJ
Date of judgment: 28 October 2011
Catchwords:

PATENTS – characterisation of invention in priority document – whether method disclosed in priority document is confined to particular encapsulated formulation – relevance of claims of priority document to characterisation of invention

PATENTS – characterisation of invention in patent – whether invention involves discovery of new method with any formulation

PATENTS – validity – external fair basis – priority date –
whether amended claim is “in substance disclosed” in priority document

PATENTS – validity – internal fair basis – relevance of consistory clause mirroring claim of patent – whether claims encompassing a formulation using hydrogel technology lack fair basis where specification states that attempts to produce a formulation using hydrogel technology were fruitless and such a formulation is impossible to achieve – whether claims unconfined to treatment of depression lack fair basis where specification refers only to depression

PATENTS – validity – sufficiency – relevance of statements made in specification that attempts to produce formulation using hydrogel technology were fruitless and such a formulation is impossible to achieve – relevance of failure to provide description to enable performance of claimed methods using hydrogel tablet technology

PATENTS – validity – false suggestion – relevance of expert evidence concerning statement made in specification that production of formulation using hydrogel technology is impossible to achieve – whether statement was a false suggestion material to grant of patent – whether statement that attempts to produce formulation using hydrogel technology were fruitless was a false suggestion material to grant of patent – relevance of absence of evidence from Commissioner

PATENTS – validity – false suggestion– relevance of failure to nominate all inventors correctly 

PATENTS – validity – clarity – definition of therapeutic blood plasma concentration – where further steps required to ascertain whether a particular formulation infringes patent

PATENTS – validity – obviousness – expert evidence – whether knowledge of existence of patent and of successful formulation taints experts’ conclusions with hindsight

PATENTS – validity – entitlement – relevance of failure to nominate all inventors correctly – evidentiary onus

PATENTS – infringement – whether claims of patent should be construed to exclude hydrogel technology

Legislation:

Foreign Corporations (Application of Laws) Act 1989 (Cth) s 7(3)(a)

Patents Act 1990 (Cth) ss 7(2), 7(3), 15(1), 18(1)(b)(ii), 40(2)(a), 40(3), 114, 138(3)(b), 138(3)(d), 138(3)(e), 138(3)(f)
Patent Regulations

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Details
Case
[2011] FCAFC 132
Decision Date

CaseChat Overview and Summary

Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth is an Australian court decision that addresses several issues concerning the validity and scope of a patent related to a method and formulation for administering a drug, venlafaxine hydrochloride. The dispute primarily revolves around whether the patent claims are valid, sufficiently disclosed, and whether they infringe on any prior art. The case was heard in the Federal Court of Australia.

The legal issues at the heart of this case include the characterisation of the invention as disclosed in the priority document, the fair basis of the patent claims, and the validity of the patent in light of prior disclosures and technical limitations. Additionally, the court examined whether certain claims were sufficiently disclosed in the priority document, whether they were obvious, and if there were any false suggestions or misstatements that could affect the patent's validity.

In delivering the judgment, the court found that the claims of the patent were not fairly based on the priority document, as they extended beyond the specific formulation and method disclosed. The court emphasised that the priority document only disclosed a particular encapsulated formulation and a method associated with that formulation. The broader claims of the patent, which included methods for administering any extended-release formulation, were deemed to extend beyond the fair basis provided by the priority document. The court also noted that the specification contained statements about the impossibility of achieving certain formulations, which further constrained the scope of the invention. Consequently, the patent claims that went beyond the specific invention disclosed in the priority document were invalidated.

The court's decision ultimately led to the invalidation of certain patent claims due to their lack of fair basis in the priority document, and the court ordered the parties to submit proposed orders within a specified timeframe.

Orders

Orders of the court

1. The parties are to submit proposed agreed orders or, if there is no agreement, each party should submit proposed orders, accompanied if desired by submissions of no more than 3 pages, within 7 days.

Note: Entry of orders is dealt with in Rule 39.32 of the Federal Court Rules 2011

Background

Background to the litigation

Full text does not contain this section.

Evidence

Evidence Before The Court

Full text does not contain this section.

Decision

Reasons for decision

The key issue is the description and characterisation of the invention disclosed in the Priority Document, which I have already discussed above.The primary judgment Her Honour found at [165] that the relevant claims of the Amended Patent were disclosed in the Priority Document. This was based on her Honour’s conclusion that the Priority Document disclosed the two inventions of:·an encapsulated formulation; and·a method for obtaining a certain drug to plasma relationship over time. Her Honour said that when the Priority Document is read as a whole, the method there disclosed was not confined to the particular encapsulated formulations, embodiments or examples disclosed. In coming to that conclusion, her Honour discounted the references to the inventor’s failed efforts to prepare a hydrogel tablet formulation and to the fact that claims 9 and 10 of the Priority Document, which claimed a method, were themselves restricted to a method comprising the administering of ‘an encapsulated, [ER] formulation’.Consideration Based on my consideration of the invention of the Priority Document above, if Wyeth relies on the whole of the Priority Document for external fair basis, the claims of the Amended Patent are wider than the invention there disclosed which, as I found above and as is claimed in claims 1 to 8 of the Priority Document, is limited to the ER formulation described in the body of that specification. The claimed methods of the Amended Patent are not so limited. The subject matter of each of claims 1 to 17 and 27 of the Amended Patent is not fairly based on the matter disclosed in the Priority Document and those claims claim matter in substance disclosed as a result of the 2006 Amendments. If the claims of the Amended Patent are to a method that includes the administration of a formulation utilising hydrogel technology, they travel beyond the disclosure of the Priority Document and are not fairly based. The description of the invention in the Priority Document is of the specific formulation as claimed in claims 1 to 8 of that document. As I found above, the invention of the Priority Document does not include a formulation based on hydrogel tablet technology. The claims of the Amended Patent, which include such formulations, are thereby not fairly based. Wyeth relies on claims 9 and 10 of the Priority Document, standing alone, to provide fair basis for claims 1 to 17 and 27 of the Amended Patent. Claims 1 to 17 of the Amended Patent are each to any ‘single daily dosing formulation of venlafaxine hydrochloride’ whether encapsulated or not. Claim 27 is to a method according to any of the preceding claims ‘wherein the formulation is an encapsulated formulation’. Claims 9 and 10 cannot be read in isolation to provide fair basis for these claims. The invention described in the specification of the Priority Document also circumscribes a proper construction of claims 9 and 10. As described earlier in these reasons, that is not any formulation or any encapsulated formulation but the formulation or encapsulated formulation of the invention of the Priority Document.

Ratio Decidendi

Legal Principle Established

The appellants challenge these findings and submit that the only invention described in the Priority Document is the encapsulated formulation.Consideration The essential integers of claims 1 to 5 include:·an encapsulated ER formulation of venlafaxine hydrochloride;·a hard gelatin capsule containing a therapeutically effective amount of spheroids comprised of venlafaxine hydrochloride, microcrystalline cellulose and HPMC, with the spheroids being coated with a composition of ethyl cellulose and HPMC. Claim 6 is to a particular film coating composition which includes, as an essential integer, HPMC. Claims 7 and 8 are each to an ER formulation of venlafaxine hydrochloride for once daily administration. The essential integers include spheroids containing, inter alia, HPMC and a coating containing, inter alia, HPMC. Claims 9 and 10 are method claims. The essential integers of claim 9 are:·a method for providing a therapeutic blood plasma concentration of venlafaxine over a 24 hour period with diminished incidences of nausea and emesis;·administering orally to a patient an encapsulated ER formulation; ·the formulation provides a peak blood plasma level of venlafaxine in from about four to about eight hours. The essential integers of claim 10 are:·a method for eliminating the troughs and peaks of drug concentration in a patient’s blood plasma;·attending a therapeutic metabolism of plural daily doses;·the administration of an encapsulated ER formulation; ·that provides a peak blood plasma level of venlafaxine in from about four to about eight hours. While claims 9 and 10 do not expressly specify the nature of the formulation, in each case the formulation is in an encapsulated ER form. An issue before the Court in considering the invention of the Priority Document is whether the Priority Document, in particular claims 9 and 10, includes a method for using any ER formulation, including hydrogel tablets. The Priority Document describes the conventional approaches to ER drug formulations. They are conventionally produced as compressed tablets by hydrogel tablet technology and, when the production of tablets is not feasible, it is conventional to prepare encapsulated drug formulations which provide extended or sustained released properties. Venlafaxine and venlafaxine hydrochloride were both known. However, the hydrochloride of venlafaxine was extremely water soluble. IR dose formulations were known but produced side effects and could not be utilised because the compressed tablets produced by that technology were either physically unstable or dissolved too rapidly in solution studies. The body of the specification of the Priority Document is explicit. It states that it was completely unexpected that an ER formulation containing venlafaxine hydrochloride could be obtained because of its extreme water solubility. The specification states that numerous attempts to produce ER tablets by known hydrogel technology proved to be “fruitless”. That is, conventional hydrogel tablet technology could not be utilised. This created a need for a different ER formulation of venlafaxine hydrochloride.