Parametritis: inventive step - Euroceltique S.A. v Sandoz Pty Ltd [2009] APO 21 (12 November 2009)

Date: 2009-11-20
Author:

This decision1 of the Australian Patent Office (Office) is of interest to the extent that it outlines the approach that the Office will take in considering the validity of a claim limited by reference to specified parameters.

The relevant claim related to:

‘A controlled release, oral pharmaceutical preparation suitable for dosing every twelve hours containing 50 to 400 mg of tramadol or pharmaceutically acceptable salt thereof (calculated as hydrochloride) in a controlled release matrix, the preparation containing between 1 and 80% w/w of one or more hydrophilic or hydrophobic polymers and having the following dissolution rate in vitro when measured using the Ph. Eur. Paddle Method at 100 rpm in 900 ml 0.1N hydrochloric acid at 37°C and using UV detection at 270 nm:

between 5 and 50% (by weight) tramadol released after 1 hour,

between 10 and 75% (by weight) tramadol released after 2 hours,

between 20 and 95% (by weight) tramadol released after 4 hours,

between 40 and 100% (by weight) tramadol released after 8 hours,

more than 50% (by weight) tramadol released after 12 hours,

more than 70% (by weight) tramadol released after 18 hours,

more than 80% (by weight) tramadol released after 24 hours.’

While inventive step was the foremost issue, the Office provided its view on whether this claim language is acceptable, and whether in the circumstances it could give rise to grounds of opposition. According to the Office, the question is one of ‘whether the parameters ….have been chosen to achieve a technical effect, or whether they are an arbitrary convenience’. As explained below, in the decision the Office found that the parameters defining the dissolution profile as claimed did have a technical effect. However, this in itself did not save the patent from a finding of lack of inventive step.

A preliminary issue was whether any preparation that achieves a 12-hour sustained release would inevitably possess the dissolution profile of the opposed claims. In finding that the specification did not provide any explanation for the claimed dissolution profile, other than that this would achieve sustained release for a 12-hour dosing, the Office formed the view that all preparations that have a 12-hour sustained release would have the claimed dissolution profile.

Turning to inventive step, the first issue for determination was the technical problem, specifically whether the problem lay in the provision of an alternative pain relief preparation, or the provision of a sustained released preparation of tramadol. What becomes clear is that the Commissioner is influenced by his reading of a patent specification in his formulation of a technical problem in circumstances where expert evidence does not enable him to conclude on the point. Ultimately, given the teaching of the specification, the problem was seen as the provision of a sustained release tramadol preparation suitable for 12-hour dosing.

It appears from the decision that the identification of the technical problem was critical to the outcome on inventive step insofar as in light of the problem, the Commissioner then considered which specific documents the skilled worker could be reasonably expected to have ascertained. The latter is particularly important in inventive step considerations because in circumstances where the finding is that a document could not have been reasonably expected to have been ascertained (as was held in relation to certain documents in the decision) the relevant document does not form part of the prior art base for assessment of inventive step.

Given the problem was seen as the provision of a sustained release tramadol preparation suitable for 12-hour dosing, the Commissioner then found that it would have been reasonable to have expected the skilled worker, confronted with this problem to have ascertained documents that relate to tramadol and sustained release, and in particular to have ascertained EP147780. As discussed below this document was fatal on the inventive step ground. One wonders whether evidence rejecting the proposition that these documents would have been ascertained might have avoided this outcome, as the Commissioner stated: ‘it is prima facie reasonable to expect that they could have been ascertained. However, suitable evidence to the contrary might displace this view. In the present case I have no such evidence.’ It is also possible that the applicant may have been in a better position had its declarants not provided different views as to their understanding of the technical problem.

Having so identified the technical problem, and noting that the claimed solution was the form of a preparation having a defined in vitro dissolution profile, the Commissioner then applied the Australian test for inventive step, which has been often stated as: ‘whether the hypothetical addressee faced with the same problem would have taken as a matter of routine whatever steps might have led from the prior art to the invention, whether they be the steps of the inventor or not’.

Importantly, the Commissioner here noted that ‘what must be considered is whether a preparation falling within the dissolution profile of the claim would have been obvious, not whether the dissolution profile would have been obvious.’ As the Commissioner had already determined that any tramadol preparation suitable for 12-hour dosing would have the claimed dissolution profile, he framed the question as whether it would have been a matter of routine to prepare a sustained release form of tramadol, and if ‘yes’, whether such a preparation would fall within the scope of the claims. In his view, the evidence showed that while adjusting a preparation to alter the dissolution rate may have been difficult, it would have been a routine process.

In the above circumstances, and having formed the view that:

  1. the expert evidence had established that sustained release formations were well known, and
  2. EP147780 disclosed a sustained release system suitable for tramadol that would have been routinely adjusted to achieved sustained release of over 12 hours, the Commissioner held the claim to lack inventive step.

The take-home message is that even where claimed parameters can be said to give rise to a technical effect, this alone will not save a claim from a finding of obviousness, and the risk of invalidity increases where no technical problem is apparent, other than the provision of a solution, and any routine adaptation of the prior art directed to solving the 'problem' would embody the claimed parameters.

 

Endnotes

1. Euroceltique S.A. v Sandoz Pty Ltd [2009] APO 21 (12 November 2009)