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Teva UK Limited v Boehringer Ingelheim Pharma GmbH, High Court of England and Wales (Morgan J), London UK, 21 October 2015, Neutral Citation Number: [2015] EWHC 2963 (Pat).

Boehringer Ingelheim’s proposed amendments to claims 5 and 6 of European Patent (UK) 1 379 220 (the “Patent”) for the use of a hydroxypropylmethylcellulose ("HPMC") capsule of a certain moisture content for the delivery of tritropium bromide in a dry inhaler was refused as the amended claims were not inventive. In particular, the specification of certain moisture levels in the claims was arbitrary and could not save the claims where the suggestion to use HPMC capsules was in itself obvious.

The Patent covers capsules to be used in a dry powder inhaler for the purpose of delivering tiotropium bromide to patients with chronic obstructive pulmonary disease (“COPD”) or asthma. Teva commenced a revocation action in June 2014 primarily on the basis of lack of inventive step. During the course of proceedings Boehringer applied for permission, pursuant to section 75 of the Patents Act 1977, to unconditionally amend the Patent claims.

This judgment considered the proposal for amended claims 5 and 6 sought by way of the unconditional application to amend, and claims 6A or 6B as set out in a further conditional application to amend that was made during trial. An unconditional application involves the patentee abandoning the claims as granted, whereas a conditional application is a fallback position should the Court hold the granted claims (or in this case the claims introduced by way of the unconditional amendment) to be invalid.

The Claims

The relevant claims were for hydroxypropylmethylcellulose (“HPMC”) capsules, which contain an inhalable powder of tiotropium bromide and lactose as the excipient, with a water content of less than X%. The difference between each claim being the value X, or the point at which X is measured.

Common General Knowledge

Morgan J, in applying the Windsurfing/Pozzoli guidelines on inventive step, determined the skilled person as a team consisting of a clinician and a formulation scientist. The clinician would have identified tiotropium bromide (which had been widely disclosed at the priority date) as a promising product for the treatment of COPD, especially as a new drug for treatment of this indication was rare at the priority date and publications would attract interest. 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. On this basis, the two potentially innovative elements of the claims were the choice of capsule material and the effect of the water content.

At the priority date, gelatine was the conventional material for capsules in dry powder inhalers. Ogura, one of the cited pieces of prior art, contained a direct comparison of the features of HPMC with gelatine and a table setting out the moisture content of both. However, the judge ruled that Ogura was not common general knowledge as the publication was not sufficiently widely read. As Ogura appeared to be the only prior art disclosure of the use of HPMC as a capsule material in a dry power inhaler, the possible use of HPMC in such manner was not common general knowledge.

Prior Art

As Ogura highlighted the benefits of HPMC capsules over gelatine capsules, Morgan J held that, if it was read by a formulation scientist it would prima facie establish in that person’s mind that the mere idea of using HPMC as a capsule material was not innovative, although there could be reasons why the formulation scientist would not follow up the idea put forward in Ogura.

Boehringer submitted three such reasons existed: (i) the formulation scientist would think that “there is nothing in this for me for present purposes”; (ii) the formulation scientist would have technical and practical reasons for rejecting HPMC; and/or (iii) there were potential regulatory hurdles to overcome in using HPMC over gelatine.

In relation to the first two points, Morgan J considered that the formulation scientist would: (i) believe there was relevant content due to known issues with gelatine moisture content; and (ii) be able to devise a suitable test using their common general knowledge to dispel any practical issues. As to regulatory issues, these were only relevant where the alleged delay or difficulty in obtaining regulatory approval was an obstacle to manufacture of the claimed product, as distinct from the marketing and sale of the product once manufactured (Re Richardson-Vicks Inc’s Patent) (i.e. distinguishing permissible technical considerations from impermissible commercial considerations relating to inventive step). In any event, in this case it was not suggested that use of HPMC would lead to refusal of regulatory approval. Although gelatine had been approved and was the conventional material, it was not wholly satisfactory. The disclosure regarding HPMC in Ogura would therefore have been very interesting to the formulation scientist, and would have been motivation to include HPMC as a possible capsule material. On the facts the skilled person would not have been put off by regulatory considerations from continuing pre-formulation on that basis. Hence, the use of an HPMC capsule per se was obvious over the common general knowledge and Ogura. Of interest is that the judge (who is not one of the three patent specialists in the Patents Court) approached this question both on the Windsurfing/Pozzoli and EPO problem-solution approaches.

Therefore, the claims would only be inventive if the limitation to certain claimed moisture content levels involved an inventive step. The Patent specification disclosed various ranges of capsule water content and Teva submitted that the claims were arbitrary and lacked a plausible technical contribution in line with the approach identified in T939/92 AGREVO/Triazoles and subsequent cases, in particular Generics (UK) t/a Mylan v Yeda. Morgan J held that the specification did not disclose that the claimed invention has the technical significance claimed for it, as whilst the specification disclosed the basic benefit of the reduction of moisture content in the HPMC capsule material (which was held to be obvious) it failed to explain the benefit of reducing the moisture content to the specific levels claimed. Morgan J also considered (post-filed) experimental evidence that the patentee said demonstrated that lower moisture levels in HPMC capsules demonstrated a technical benefit as regards the stability of tiotropium. Whilst he had some doubts about the quality of the results, in any event the judge held that if the moisture levels in the claims were arbitrary based on the disclosure in the Patent; the results of later experiments not referred to in the patent could not save the claims.

As a result, Morgan J held that all of the claims as proposed to be amended (both by way of the unconditional and conditional applications) to be lacking inventive step.

Read the judgment here.

Headnote: Thomas Hendicott, Bristows LLP