Insights 15.04.2021

Managing priority in US and European patents

While protecting patentable innovations in the US and Europe is the foundation of many corporate patent portfolios, differences in priority arrangements in the US can cause issues obtaining subsequent protection in Europe. Novagraaf’s Nadège Lagneau offers advice on overcoming the priority disconnect.

Patent priority arrangements made according to US practices can lead to issues with European patent (EP) applications, as was highlighted by the European Patent Office’s ruling on the CRISPR gene-editing patent last year. Vigilance is recommended therefore where protection in Europe is also desired for US inventions.

Avoid potential pitfalls

There are a number of areas where applicants may get caught out, but disparities over ownership pose some of the biggest risks.

This is because the owner of a US patent application is typically its inventor (unless otherwise agreed by contract), even if that inventor is a salaried employee. In Europe, on the other hand, patent applications are filed (including in the EPC and PCT systems) in the name of the employer, as employers are deemed to own the innovations of a salaried inventor (unless otherwise agreed by contract).

Differences in ownership between the priority US patent application (in the name of the inventor) and a subsequent patent application (in the name of the employer) claiming priority can cause problems in Europe. If the ownership of the right of priority cannot be conclusively demonstrated, that priority claim may be challenged in opposition proceedings, leading to its invalidation.

That causes additional problems, as the loss of a priority claim then generates the very real risk of the patent being revoked due to the publication of prior art in the dates between the filing of the priority US patent application and that of the subsequent application.

Overcoming the challenge

Although the America Invents Act (AIA) provides that US patent applications can now be filed by designating employers as applicants/owners, under US law, inventors named on a US patent application are presumed to own the invention, except in the case of contrary contractual provisions (e.g. an employment contract or via assignment). In the absence of a specific assignment signed by the inventors, it is up to the employer to prove that they are indeed the owner of the rights to the invention that is the subject of the priority patent application.

As such, for a first patent filing in the US – whether a provisional or regular patent application – it is generally advisable to:

  • Have the inventors sign an assignment (of their rights to the invention) shortly after the filing and, in any event, before the filing of the subsequent patent application (eg PCT or EP) claiming priority of the US patent application;
  • This assignment should include the number of the US patent application (plus its filing date and title) that is the subject of the priority US patent application, and also cover the assignment of the priority right (which is a right distinct from the right to the invention) to their employer/supervisory institution.
  • Register the assignment(s) at the USPTO (usually one assignment per employer/parent institution); and
  • Ensure the above is completed before filing the subsequent patent application (e.g. PCT or direct EP patent filing) claiming priority of the US patent application.

Following these steps is a simple and inexpensive precaution that can help the applicant to avoid complicated debates in Europe (e.g. if the priority claim is challenged by a third party in opposition), and makes it possible to secure the priority claim in the case of a first patent filing in the US.

As a general rule, it is also advisable to ask any related partners/institutions with whom the first US patent application is filed to follow these steps, whether or not these partners or institutions are based the US.

For further detail or specific support from a European Patent Attorney, please contact us.

Nadège Lagneau is a European and French Patent Attorney based in Novagraaf’s Paris office.

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