Barcelona patent court holds oxycodone/naloxone patent invalid due to added matter

On 19 December 2018, Commercial Court No. 4 of Barcelona dismissed a patent infringement action brought by Mundipharma against two generics in Spain of its oxycodone/naloxone medicinal product for the treatment of pain (Targin®), and upheld the defendants’ counterclaim for invalidity of the asserted patent.

The dispute

Mundipharma is the holder of European patent EP2425825 (hereinafter EP’825), entitled ‘Pharmaceutical preparation containing oxycodone and naloxone’. Claim 1 of the patent relates to an oral sustained release pharmaceutical formulation comprising 10-150 mg of oxycodone hydrochloride and 1-50 mg of naloxone hydrochloride in a weight ratio of 2:1.

In April and May 2018 Mundipharma filed infringement actions against two generic companies, while also seeking preliminary injunctions.

The preliminary injunctions were initially granted ex parte, but were subsequently revoked on the grounds of prima facie invalidity of Mundipharma’s patent. The decisions revoking the preliminary injunctions were confirmed on appeal.

In the main proceedings on the merits, the defendants claimed that EP’825 was invalid due to added matter, insufficiency of disclosure, lack of novelty and lack of inventive step. In particular, as regards to added matter, they argued the following:

  • The claims of the patent as granted amounted to a selection and combination of features, which was not individualised in the original application as filed;
  • The claims of the patent as granted entailed an inadmissible generalisation of the original application as filed, omitting essential features of the latter.
  • There was also an intermediate generalisation where the patentee attempted to argue that the specific combination of features of claim 1 derived from the examples of the application as filed.

The patentee counterargued that all the claimed features were preferred features within the application as filed, thus constituting a clear pointer that led to their specific combination. Mundipharma, by way of an ancillary claim, also filed an auxiliary request, claiming an oral sustained release pharmaceutical formulation comprising 20 mg of oxycodone hydrochloride and 10 mg of naloxone hydrochloride.

Shortly before the trial, the Opposition Division of the EPO announced the revocation of the asserted patent due to added matter.

The decision

The Court upheld the defendants’ counterclaims and revoked the patent in a ruling deliberated by the three Patent Judges of Barcelona.

The judgment first analysed all the features of claim 1 of the patent as granted, namely:

  • The selection of oxycodone’s hydrochloride salt
  • The selection of naloxone’s hydrochloride salt
  • The amount of oxycodone hydrochloride (10-150 mg)
  • The amount of naloxone hydrochloride (1-50 mg)
  • The specific 2:1 ratio

The Court stated that there was no pointer in the original patent application leading to the specific five-element combination as ultimately claimed. Hence the combination of features of claim 1 could not be ‘directly and unambiguously’ derived or deduced by the person skilled in the art.

Moreover, the judgment explained that the claims of EP’825 would amount to an inadmissible generalization because they omitted essential elements of the invention as disclosed in the application as filed. More specifically, whereas the original application required at all times that the formulation provide an invariable and independent release, the claims of the patent as granted did not require such release to be ‘invariable and independent’.

The Court found it unnecessary to further tackle the rest of the invalidity grounds brought by the defendants (i.e. insufficiency of disclosure, lack of novelty and lack of inventive step).

Lastly, the Judge examined the validity of the auxiliary request filed by Mundipharma, and concluded that it also incurred in added matter due to selection/combination of features and inadmissible generalisation.

Mundipharma has not appealed this judgment, and so the revocation of the patent is final in Spain.