The Full Federal Court of Australia (Bennett, Nicholas and Yates JJ) recently found that the majority of Wyeth's patent claims covering a method of administering the antidepressant compound venlafaxine hydrochloride (Patent) were invalid (see Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth  FCAFC 132).
The Full Federal Court based its decision on a finding that the Patent was not entitled to its earliest priority date. Wyeth had accepted that, without the earliest priority date, the patent lacked novelty – perhaps not surprising given the loss of 10 years' priority. The decision highlights the care required when amending patent claims to ensure they are not broadened such that they cease to be fairly based on the specification and any priority documents.
The complete specification of the Patent was first filed in 1997 and claimed a priority date of 1996 based on a US patent application (Priority Document). In 2006 the Patent was amended by removing references to 'encapsulated extended release' (ER) formulations from the specification and claims.
At first instance, Jagot J found that the Priority Document disclosed two inventions: an encapsulated ER formulation, and a method for controlling drug plasma levels, but the method was not confined to the encapsulated ER formulations of the Priority Document. Accordingly, the Patent (as amended) was fairly based on the Priority Document (and Sigma had threatened to infringe the Patent).
Wyeth submitted that the claimed method represented a new result or thing, obtained by a new application of principle as in Lockwood Security Products Pty Ltd v Doric Products Pty Ltd (2004) 217 CLR 274. In that case, the High Court rejected notions of 'inventive merit' in assessing fair basis. In assessing whether a claimed invention is fairly based, the High Court held that it is only necessary to consider what the specification describes as the invention. Accordingly, Wyeth submitted, the inventor may claim all the alternative means by which the thing or result may be achieved.
With respect to fair basis, Wyeth relied on references in the specification of the priority document, including the consistory statement, to the provision of an encapsulated ER formulation containing venlafaxine hydrochloride, unlimited by reference in that sentence to the particular spheroid formulation the subject of the later examples. In essence it argued that all that was required was a mere comparison of the claims and the relevant priority document to assess whether there is a disclosure that mirrors and supports the claims as a matter of drafting of words.
The Full Court held that the invention was not the discovery of a new method with any formulation. The method disclosed is the use of the invention, the ER formulation. It also emphasised that Lockwood does not set down a superficial test based solely on the presence or absence of words. Rather, the words must be construed in the context of the document as a whole.
In the case of external fair basis, the Court acknowledged that 'a development along the same line of thought which constitutes or underlies the invention described in the earlier document' may be fairly based. However this principle must not derogate from the requirement that the priority document must in substance disclose the claimed invention.
The Court found that properly construed, the Priority Document was limited to encapsulated ER formulations (further, it even expressly taught away from the use of conventional (non-encapsulation) formulation techniques). The consistory statements in the Priority Document did not help Wyeth – such statements were said to be 'in accordance with this use aspect of the invention' and therefore limited to the invention, ie. the ER formulation.
Accordingly both the product and method claims of the Patent were not fairly based in the Priority Document (ie. the was no external fair basis for those claims).
The Court also considered whether the claims were fairly based on the specification (ie. internal fair basis). The Court emphasised that the specification must contain a 'real and reasonably clear disclosure' of what is claimed. In this case, the invention was in the context of a finding that an ER formulation was impossible to achieve using conventional (hydrogel) technology. The amended claims covered such conventional technologies and, accordingly, were not fairly based on the specification.
Intellectual Property Laws Amendments Bill
The decision echoes the amendments proposed by the Intellectual Property Laws Amendments (Raising the Bar) Bill 2011 currently before the senate. That Bill proposes a number of amendments to the Patents Act with a view to raising Australian patentability standards in line with international standards.
The current 'fair basis' test (both for internal and external fair basis) would be replaced with a support requirement - there must be basis in the specification for each claim and the scope of the claims not extend beyond that justified by the description, drawings and contribution to the art.
Author(s) Dennis Schubauer, John Fairbairn