Patents: invalidity due to improperly claimed priority

Background

In certain circumstances a patent applicant will be entitled to a priority date up to 12 months earlier than the date on which it was actually filed. "Any person" who has filed an application for a patent will, for a European patent application filed later in respect of the same invention, enjoy a right of priority during a period of 12 months from the date of filing of the first application (Article 87, European Patent Convention; Article 4, Paris Convention) (Article 87). The right is also enjoyed by the person's successor in title.

"Any person" in Article 87(1) means that all applicants for the priority application, or their successors in title, must be applicants for the subsequent application (T 788/05). This can lead to challenges, in particular where the first application is US, because it was previously a requirement of US patent law, and has continued as common practice, that the actual inventors must be named, even if they have assigned their rights to their employer or another applicant. According to EPO case law, this assignment must be performed before the European patent’s filing date (T1201/14).

Priority sets the date on which the state of the art is considered for the purpose of assessing the novelty or inventive step of an invention. The earlier the priority date of a patent application, the earlier the cut-off date for the state of the art. So, when the novelty or inventive step of the patent or patent application is considered, there is likely to be less relevant prior art if an earlier priority date is maintained. If the claim to priority is held to be invalid, prior art published during the priority period may affect patentability.

Facts

B claimed priority from 12 US provisional patent applications for its European patent relating to the gene-editing technology known as CRISPR.

The EPO opposition division held that priority had not been validly claimed from some of these US applications because the European patent applicants differed to those for the US applications, or their successors in title, specifically, one US applicant was missing from the European application and no applicant was said to be his successor in title. This meant that certain novelty-destroying documents became prior art to the European patent application, so that the patent was invalid.

B appealed, arguing that the EPO should not have assessed the entitlement to priority, and that it had wrongly interpreted Article 87(1) in determining that the priority claim was invalid. B argued that:

• The EPO should no longer assess whether the applicant of the subsequent application is entitled to the priority right and instead the assessment should be solely whether the claimed invention is disclosed in the priority application.
  
  
• Alternatively, "any person" in Article 87 should be interpreted to mean that any one person who duly filed the priority application or their successor in title could validly claim priority. "Any" did not mean "all". The EPO practice of requiring all applicants for the priority application or their successors in title to be applicants for the subsequent application was incorrect.
  
  
• The identification of the person who had duly filed the application should be carried out in accordance with the law of the territory in which the priority applications were filed, in this case the US. Under US law, there were no missing applicants as applicants are only recognised for the invention to which they have contributed. Here all the inventors who had contributed to the invention claimed in the European application were persons who had duly filed, or applicants, and so priority was validly claimed.

Decision

The TBA dismissed the appeal.

Article 87(1) does not require that the "any person" who filed the patent application was legally entitled to do so. The EPO does not carry out any substantial assessment of the legal entitlement to property rights; it merely makes a formal assessment of the person who filed the patent application. Failure to comply with a formal requirement of the EPC can destroy a patent or patent application, irrespective of whether it satisfies the substantive requirements for patentability. Here, B had chosen the named applicants in a way that did not comply with the well-established practice of the EPO.

The EPO will assess on the evidence whether there is a successor in title of the original applicant, although there was no successor in title here. Such an analysis involves a substantial legal assessment but not an assessment of legal entitlement to a priority right.

The TBA assessed B's "one or more applicant" approach but concluded that the arguments for the "all applicants" approach were stronger. This approach has been applied since the early 20th century by the current member states of the EPC, and during the 21st century by the EPO.

The TBA considered whether the interpretation of "any person" was a matter of national law. The US is a party to the Paris Convention, which provides that it is national law that determined whether a filing is one that establishes a filing date. However, whether these persons are the inventors of what is claimed or are entitled to be the applicants for this patent are not issues requiring investigation under the Paris Convention. The identification of the "any person" is purely formal. There is no requirement for the "any person" to be legally entitled to make the filing, merely that they did so.

Given the special characteristics of US provisional applications, B must be aware of the difficulties they might face if they used these applications to claim priority for a European patent application, as a consequence of the US's adherence to the Paris Convention. It followed that the national law that determined who "any person" was for this case was the Paris Convention. As a result of the decision on the meaning of "any person", priority had not been validly claimed. The patent was invalid for lack of novelty and would be revoked.

Comment

The problem here arose because of the requirement of US patent law that the actual inventors must be named, even if they have assigned their rights to their employer or another, and the number of individual inventors and employing institutions involved in this inventive activity. While the naming of inventors made sense in the US patent system, when inventors were usually individuals, it is very difficult to apply to the development of complex inventions made by large teams such as this one. In cases of doubt, US applicants may tend to err on the side of caution and name more individuals when originally filing. Particular problems can arise, as here, if a US provisional application is used as the priority application, because by the time the subsequent application is filed the actual inventorship may have become clearer. The problem may be alleviated by naming companies or institutions as applicants on US applications as is now permitted under the America Invents Act, or by ensuring that assignments from all relevant applicants are executed before filing a subsequent European application.

Case: CRISPR-Cas/Broad Institute T-0844/18.