Patent nullity actions

Lack of novelty or inventive step over the prior art, insufficiency of disclosure, extension of subject matter beyond the application as filed, extension of protection after grant. Each ground calls for a method: prior art searches (patent databases and technical literature), reconstruction of the state of the art at the filing date, reading of the claims with the person skilled in the art as the compass.

On plausibility and priority, the French solution adopted in the Apixaban case takes the opposite view to the British decision in the same case.

Validity can be challenged before the Paris Judicial Court (nullity action), before the UPC (revocation action), or before the EPO by way of opposition, within nine months of grant (art. 99 CBE): each with its own time limits, costs and territorial effects. The proprietor may respond by limiting its claims (art. L. 613-24 CPI, art. 105 bis CBE). We conduct the litigation in attack and in defence and coordinate EPO proceedings with patent attorneys, and it is precisely that twofold practice that makes our validity analyses realistic.

The nullity action is not subject to limitation (Article L. 615-8-1 CPI): an old patent remains open to challenge, including after expiry where an interest subsists, in particular to neutralise a claim for damages relating to the past. Invalidity may also be raised as a defence to an infringement action, without being confined by the ordinary limitation period.

Since 1 April 2020, French patents whose grant was published on or after that date may be opposed before the INPI within nine months of publication (Order no. 2020-116 of 12 February 2020). Utility certificates are excluded. This route is far less costly than a trial, but it is confined to a short time limit and its outcome often shapes what follows: it is a decision to take in the weeks after the grant of the troublesome patent, not when the dispute breaks out.

The revocation action before the Unified Patent Court takes effect in all Contracting Member States for which the European patent has effect (Article 65 of the Agreement). It therefore exposes the proprietor to centralised revocation, without waiting for an opposition to be opened or decided. That risk explains the massive use of theopt out during the transitional period, and it must be weighed before attacking: a revocation obtained in Paris applies only to France, a revocation obtained before the Unified Patent Court applies to the whole territory covered.

A revocation action is only as good as the prior art produced. The work begins with a broad documentary search, patents and non-patent literature, completed by reconstructing the common general knowledge of the person skilled in the art at the priority date, and by examining the prosecution history, which often reveals the concessions made by the applicant. The timetable of the attack is finally aligned with that of the industrial project it is meant to serve: a launch, a fundraising, a licence renegotiation.