Fair reward for fair disclosure

Fair reward for fair disclosure - Griffith Hack

23 April 2012

Griffith Hack achieved victory for its client, Sigma Pharmaceuticals, in a patent fight with Wyeth over its multibillion dollar drug venlafaxine hydrochloride.

What you need to know



  • It is important in any challenge to the validity of a patent to understand the prosecution history.
  • It is common for patent claims to be amended during the prosecution of a patent. However amendments to the description of an invention may be at best a waste of money, and at worst undermine the validity of the claims.
  • Amendments that re-characterise the scope of the invention will defer the priority date (ie. The date against which novelty and inventiveness is measured) of claims which need the amendments for support, undermining their validity.

By maintaining the same key argument through interlocutory, trial and appeal proceedings, Griffith Hack finally achieved victory for its client, Sigma Pharmaceuticals, in a patent fight with Wyeth over the blockbuster drug Effexor-XR.

The decision of the Full Court of the Federal Court of Australia in
Sigma Pharmaceuticals (Australia) Pty Ltd v Wyeth [2011] FCAFC 132)stands for the proposition that claims in an amended patent must be fairly based on the original application filed in respect of the invention (ie. the priority document) in order to be valid. While this proposition may be simply stated, the law and reasoning leading to the result is relatively complex.

Fundamental principles



Patents provide monopoly rights intended to be a reward, granted by the state, in return for an applicant disclosing to the public something of practical use that is new and inventive. The rationale for the reward is two-fold: first, to encourage research and invention, and second, to provide a mechanism by which researchers can keep abreast of what is ‘state of the art’ and avoid wasting resources investigating problems that have already been solved by others.

The requirement that the inventor disclose his or her invention to the public in the original application will be met if a skilled person can understand it and reproduce the invention.

Having regard to the underlying rationale for patents, the novelty and inventiveness of patent claims are measured against the state of the art as it is on the day that the original application is filed. This key idea should not to be contentious in view of the policy justification for patent monopolies. An inventor should not be allowed to change his mind later, for example after witnessing what his competitors are up to, and maintain his or her claim to a monopoly.

So, what happens when the applicant does change his mind and amends the description of his invention, to such an extent that a skilled reader would understand from an objective comparison of the original and amended descriptions that the invention has been recharacterised?


Amendments to the specification



What is of concern here is not amendments to patent claims, which are routinely required during the examination process, but amendments to the description of the invention in the specification. Presumably the only reason one would spend the time and effort amending a specification is to provide extra support for the claims. (If the claims don’t need the extra support, then there is no need for the amendment.) However, if such an amendment is performed, what is the effect on validity of the claims?

The facts of the case



In the case in issue, Wyeth filed an application describing an extended release formulation of the antidepressant drug, venlafaxine hydrochloride, and its use. The original application acknowledged the desirability of such formulations, described the problems associated with making such a formulation using venlafaxine, and then described how Wyeth overcame those problems by using special microspheres. The specification also contained experimental results that tended to show that the microspheres formulation that Wyeth had achieved would in fact release the drug slowly into the blood stream of patients in a way expected to be beneficial.

Wyeth then set about very successfully marketing and selling its microsphere formulation, earning US$3.7 billion from sales worldwide in 2007 alone. Sometime after the formulation had been on the market, however, Wyeth amended its Australian patent application to include claims that covered any formulation that delivered the same blood concentration
profile to patients, howsoever the formulation was made, and not limited to the microspheres described in the priority document.

Importantly, it also amended the description of the invention in the specification by adding and deleting material from the original application in order to provide extra support for the new, broader claims.


The result: what the Court found



The Full Court considered that the new claims were not fairly based on the original application. The Full Court considered that the date against which the validity of the new claims ought to be measured was, at best, the date of the amendments. Since the claims covered things that were not new and inventive as at that date, they were invalid.

The rather complex reasoning required to explain how the
Australian Patents Act 1990 (Cth) and Patents Regulations 1991 properly provided for this result is unnecessary to review for present purposes. Importantly, it seems no amendments to a specification which are made after the original application is filed in order to make the description conform to its claims can be relied on to support the validity of claims. While this is the logical extension of the Full Court’s decision, the decision does not itself make that point clear.

The final word



An application for special leave to appeal to the Full Court’s decision to the High Court presently remains on foot. The last word on a rather complex area of law relating to amendments may be yet to come.

For further information, please contact:

Wayne Condon, Principal
Email Wayne

Justin Lambert, Senior Associate
Email Justin