The opposition procedure available at the European Patent Office (EPO) provides third parties with an opportunity to contest a patent for nine months after it is granted. Opposition proceedings are the time at which a granted patent is really tested, because third parties will often expend a large amount of time and resources to attack the patent. Opposition proceedings are therefore an important part of the European patent system and often involve commercially important patents. This article summarises a recent opposition proceedings which concerned a patent which covered a commercially relevant product.

YASMIN® is the trade name of a combined contraceptive pill containing ethinylestradiol and drospirenone which is sold by Bayer Pharma Aktiengesekkschaft.

An appeal of the outcome of opposition proceedings was recently published by the EPO as decision T-1083/12. The opposition proceedings concerned European Patent number EP1598069, belonging to Bayer Pharma, and was opposed by Laboratoires Léon Pharma, S.A., Sandoz International GmbH, Teva Pharmaceutical Industries Ltd., Lupin Limited, Helm AG, Gedeon Richter Plc., and Effik Benelux N.V.

Claim 1 of the granted patent was directed to a pharmaceutical composition comprising ethinylestradiol and drospirenone, with the drospirenone present on the surface of inert carrier particles. The amounts of each of these two components were defined as separate ranges.

The various opposing parties sought revocation of the patent in its entirety, on the grounds that the subject matter claimed was not novel, was not inventive, was not sufficiently described in the application, and the application contained matter which was not present in the application as filed. These are the four grounds that opponents can raise during opposition proceedings.

Following the opposition proceedings, the patent covering YASMIN® (EP1598069) was revoked. The Opposition Division decided that the invention claimed was not described in a manner which was clear and complete enough to be carried out by the person skilled in the art. Their reasoning was that the patent did not provide sufficient details of how to perform the spraying process used to obtain the inert particles having the specified amount of drospirenone present on their surface.

Unsurprisingly, Bayer Pharma chose to file an appeal against this decision. In response, several of the parties which had originally opposed the patent, filed requests that the sppeal be dismissed (in other words, that the decision to revoke the patent in its entirety be upheld). Another party was also made party to the appeal proceedings after filing an intervention, which they were permitted to do because Bayer Pharma had begun infringement proceedings against them with respect to the patent which was the subject of the Appeal.

Several of the parties argued that Bayer’s main request in the appeal added matter over the application as originally filed. This argument was based on a disparity between what was present in claim 1 of the main request, which was directed to a tablet defined in part in having a particular dissolution profile for drospirenone, and the context in which this claimed dissolution profile was disclosed in the description of the patent.

Claim 1 of the main request was directed to a tablet comprising ethinylestradiol and inert carrier particles containing drospirenone on their surface. The part of the description which referred to the claimed dissolution profile was not, however, related to tablets containing drospirenone which had been sprayed onto the surface of inert particles, but instead referred to the dissolution profile associated with a particular micronised form of drospirenone.

The Appeal Board found that it was not clearly and unambiguously derivable from the application as filed that the claimed tablets containing drospirenone which had been sprayed onto the surface of inert particles would have the same dissolution profile as the particular micronised form of drospirenone recited in the description. There was therefore no disclosure in the application as filed of the dissolution profile recited in claim 1 of the main request in connection with the tablet claimed.

For this reason, the Appeal Board found that claim 1 of the main request added matter over the application as filed. As such, the request could not be allowed, and the decision to revoke the patent was upheld

This decision highlights the importance of high quality drafting of patent applications. In this case, the Opposition Decision revoked the patent for failing to properly describe how to prepare tablets containing drospirenone which had been sprayed onto the surface of inert particles. Bayer Pharma tried to overcome this objection by amending the claim to specify the dissolution profile of drospirenone from the tablets claimed, but the claim amended in this way was held to comprise added matter. Neither of these reasons relate to the novelty and inventive step of the claim; the invention claimed was not found to lack patentability per se. The value of investing time and resources into drafting patent applications should not be underestimated. It is critical that it is described how to put into place all of the features that are important to the invention and that could become part of a claim.