Obviousness – the Pozzoli Test, the Problem Solution Approach or Both?

November 2015

Teva UK Limited v Boehringer Ingelheim Pharma GmbH & Co KG

This decision is of interest because, unusually, the judge considered obviousness using both the Pozzoli test usually used by the UK Courts and the problem solution approach favoured by the European Patent Office. 

This judgment related to an application for post grant amendment of Boehringer’s European Patent (UK) No. 1379220. The patent related to capsules for use in a dry powder inhaler to deliver tiotropium bromide to patients suffering from chronic obstructive pulmonary disease (“COPD”) or asthma, and claimed the use of a hydroxypropylmethylcellulose ("HPMC") capsule having a particular moisture content.

Teva brought a revocation action against the patent in June 2014 on the grounds of a lack of inventive step. During the revocation proceedings, Boehringer applied to amend the claims under section 75 of the Patents Act 1977. The present judgment dealt with an unconditional application to amend claims 5 and 6 of the patent, and a further conditional amendment to claim 6 (set out as claims 6A and 6B in the judgment).

The relevant claims related to hydroxypropylmethylcellulose (“HPMC”) capsules which contained an inhalable powder of tiotropium bromide and lactose as the excipient, with a water content of less than a specified amount. The claims differed in the specified amount claimed, and the point at which the specified amount was measured.

Morgan J applied the Pozzoli guidelines to assess the obviousness of these claims. The judge determined that the skilled team would consist of a clinician and a formulation scientist. On the facts of the case the judge determined that the clinician, at the priority date of the patent, would have identified tiotropium bromide as a promising product for the treatment of COPD, and that the formulation scientist would have been aware of the use of dry powder inhalers to administer tiotropium bromide and that lactose was frequently used as an excipient.

The remaining elements of the claims were the choice of capsule material and the effect of the water content. It was known that gelatine (gelatin) was the conventional material for capsules in dry powder inhalers. However, a prior art document, Ogura, contained a direct comparison of the features of HPMC with gelatine and a table setting out the moisture content of both. On the facts of the case, Morgan J found that Ogura did not form part of the common general knowledge because the publication was not sufficiently widely read. However, the judge held that the use of HPMC was not inventive:

The description in Ogura of HPMC as a capsule material, with a low moisture content, would have been very interesting to an unimaginative formulation scientist. That property of HPMC would have been attractive to him. That would provide a motivation for him to include HPMC as a possible capsule material. I do not consider, on the facts, that he would have been put off by regulatory considerations from continuing his pre-formulation on that basis.

In relation to the question whether it would have been obvious in the light of Ogura, and in the light of common general knowledge about the general properties of HPMC, to try HPMC as a potentially suitable capsule material, I consider that the evidence establishes that it was obvious to try HPMC with a high prospect of success.

Consequently, the claims would only have an inventive step if it could be shown that the claimed moisture content levels were inventive. Interestingly, the judge applied both the Pozzoli test and the EPO problem solution approach in his reasoning on this point.

The patent disclosed various ranges of water content. However, Morgan J found that, although the specification disclosed the general benefits of a reduction of moisture content in the HPMC capsule material, it failed to disclose the benefit of the specific moisture levels claimed. As a result, the judge found the claimed moisture levels to be arbitrary and the claims were found to be obvious: 

I conclude that the use of HPMC as a capsule material in a dry powder inhaler for the
delivery of tiotropium bromide was obvious and the specification of specific moisture
levels in amended claims 5 and 6 and 6A and 6B was arbitrary. There was no
inventive step in any of these claims.

Based on this, the judge held that all the claims as proposed to be amended lacked an inventive step.

[2015] EWHC 2963(Pat)