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Getting priority claims right - an EPO/European perspective

The whole issue of claiming priority on patent applications came to a head at the European Patent Office (EPO) on 16 January 2020 when the Board of Appeal in case T 0844/18 dismissed an appeal by the Broad Institute on its CRISPR patent EP2771468 and upheld an Opposition Division’s decision to revoke the patent for lack of novelty as a result of an invalid priority claim. Yes, that's right, an invalid priority claim.

This is not the first time that this kind of situation has arisen, and it will certainly not be the last.

Priority is one of those issues which can easily go wrong, particularly where there are multiple parties working together. However, when it does go wrong and a priority claim is found to be invalid, granted patents can often be revoked.

So what went wrong in this case - why was the priority claim invalid? And what should you do to ensure that the same thing doesn't happen to one of your cases?

First things first - nothing has changed at the EPO

It's worth noting that this decision did not set a new precedent or create a new requirement for claiming priority at the EPO. The finding that the priority claim was invalid is wholly consistent with existing EPO case law.

So what happened in the Broad Institute case?

The written decision has not yet issued - it should issue within the next few months (when it does, it should be here). However, the basic facts behind the case are as follows:

  • The PCT application had a total of 12 priority claims to earlier US provisional patent applications.
  • The US provisionals named various applicant-inventors.
  • When it came to the filing of PCT/US2013/74819 (which then matured into EP2771468), various of the applicant-inventors from the US provisionals were not named as applicants on the PCT application, and there was no assignment of rights from them to the applicants who were named on the PCT application.

Because of this, various of the priority claims were invalid. Without those priority claims (specifically, without the earliest priority claim), the available prior art caused a lack of novelty.

Understanding priority - a brief 101

The "right of priority"

Article 4(A)(1) of the Paris Convention states that:

"Any person who has duly filed an application for a patent, or for the registration of a utility model, or of an industrial design, or of a trademark, in one of the countries of the Union, or his successor in title, shall enjoy, for the purpose of filing in the other countries, a right of priority during the periods hereinafter fixed."

Article 87 EPC gives effect to this at the EPO; Article 8 of the PCT gives effect to this for PCT applications; Section 5 of the Patents Act 1977 gives effect to this in the UK.

This right of priority is a property right and is created by the filing of a patent application. It is distinct from the right to be granted a patent (Edwards Lifesciences AG v Cook Biotech Incorporated [2009] EWHC 1304 (Pat) at [82]-[98]).

Ownership of the right of priority and claiming priority

Where there are multiple applicants for an application, the priority right belongs to them simultaneously and jointly (they are a "legal unity"). This means that all of them (or their successor(s) in title) must be amongst the applicants for a subsequent patent application claiming priority from the earlier application (T 0788/05 at Reasons 2). Applicants can, however, be added to the subsequent patent application without invalidating the priority claim (T 1933/12 at Reasons 2.4).

Title cannot be fixed retrospectively

If all of the applicants for the earlier application (or their successors in title) are not amongst the applicants for the subsequent patent application then the priority claim is invalid, and this cannot be remedied after filing of the subsequent patent application (Edwards v Cook at [95], J 0019/87, T 0062/05).




Successor(s) in title and equitable/beneficial title v bare legal title

If legal title to the right of priority is not with the applicant(s) of a later application, all might not be lost. The key thing here is "successor in title", and this is resolved under the relevant national law, i.e. the national law under which the transfer is effected. As is stated by Arnold, J in KCI Licensing Inc & Ors v Smith & Nephew Plc & Ors [2010] EWHC 1487 (Pat) at [71]:

"Article 4(A) of the Paris Convention and Article 87(1) of the EPC are provisions in international treaties whose operation cannot depend upon the distinction drawn by English law, but not most other laws, between legal and equitable title. When determining whether a person is a "successor in title" for the purposes of the provisions, it must be the substantive rights of that person, and not his compliance with legal formalities, that matter."

See also Idenix Pharmaceuticals Inc v Gilead Sciences Inc & Ors [2016] EWCA Civ 1089 at [265]-[266]; Accord Healthcare Ltd v Research Corporation Technologies, Inc (Rev 1) [2017] EWHC 2711 (Pat) at [53]-[78]; T 0205/14; J 0019/87; T 0517/14; T 1201/14; T 0725/14).

Overall Summary

The legal principles applicable to priority entitlement are summarised by Birss, J in Accord v Research at [75] where he states that:

"i)           Usually the right to claim priority goes with the right to the invention.  [...]

ii)           The right to claim priority must be with the person making the patent application in which that right is claimed when they make that claim, i.e. when the application is filed. A later acquisition of that right cannot make good a lack of it on the relevant date.  If the right was not in place at the time then the right is lost for all time.  That is Edwards v Cook.

iii)           But if the local law applicable to rights of the applicant and the patent application at the place and time when it was made allows for a splitting of property rights into legal and equitable interests, then it will be sufficient to establish an entitlement to priority if the applicant holds the entire equitable interest at the relevant date.  That is KCI, HTC and FujiFilm and was held in the Court of Appeal in Idenix provisionally to be correct.

iv)           A person with a legally enforceable right to call for the assignment of the legal title to a piece of property such as an invention (or a right to claim priority) has the equitable title to that property. When the cases refer to the applicant holding the substantive right and title to the invention, they are referring to this legal/equitable distinction."

Practical advice

The Broad Institute's CRISPR case emphasises the stark contrast between the interpretation of the provisions of Article 4(A)(1) of the Paris Convention under different legal systems. For example, under US law (35 U.S.C. 120 and 119(e) - see e.g. MPEP S.211), the priority claims would have been valid since other applicant-inventors on the relevant earlier applications had assigned their rights to the applicants named on the PCT application.

Our recommendations for filing a later patent application (e.g. a PCT application) are as follows:

A.           Ensure that you have a complete chain of title from each applicant on each priority application to the applicant(s) on the later (e.g. PCT) application. Where appropriate (e.g. common law countries such as the USA), determine, follow and obtain executed assignments for each step in the equitable chain of title, not just the bare legal title. Do not take shortcuts when establishing the chain of title - proving validity in 10 or 20 years time could be difficult (Accord v Research).

B.           Assignments must be in writing, and must be signed by all parties (T 0062/05). Ensure that the assignment(s) are dated before the date of filing of the later application.

C.           Ensure that the assignment(s) clearly identify the priority application(s) - filing country, application number, filing date, and that they explicitly state that both (i) the right to claim priority, and (ii) the right to grant of a patent, are being assigned.

D.           If you cannot get assignments (e.g. from inventors) executed before the date of filing of the later application (e.g. a PCT application) then include them as applicants on the later application - assignments can be subsequently executed and recorded.

Jim Robertson, Patent Attorney


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