Sean Hutchinson

February 2025

Background

It is a fundamental principle of patent laws around the world that, in return for being granted a patent for an invention, the patent applicant must disclose the invention to the public in a manner sufficiently clear and complete for a person skilled in the relevant art to then carry out the invention. This requirement is known as “sufficiency of disclosure” and failure to meet it can lead to a patent being revoked for being “insufficient”.

In this case, a third party applied to the UK High Court for revocation of its competitor’s European (UK) patent on the grounds that the patent lacked sufficient disclosure.

The patent concerned covered a method of determining whether a patient is at risk of developing a certain disease, the method involving conducting an assay and quantifying the results to calculate an “index value”. The patent disclosed that, if the index value is greater than 1.5, then it can be concluded that the patient is at high risk of developing the disease.

The third party, however, argued that the patent failed to sufficiently disclose how to set up an assay in such a way that one could be sure an index value of 1.5 would be an appropriate cut-off. The patent disclosed that the apparatus used should first be calibrated such that an index value of 1.0 is obtained when the assay is carried out using a calibrator solution, but failed to disclose the identity and composition of the calibrator solution in a manner that would enable it to be replicated.

The High Court judge (The Honourable Mr Justice Mellor) agreed with the third party, and thus held the patent invalid for lack of sufficiency.

Request for Arrow Declaration

With the patent having been declared invalid, the third party asked the High Court to grant it a so-called Arrow declaration. In particular, the third party asked the court to declare that any patent granted on the International application from which the contested European (UK) patent was derived would be invalid for lack of sufficiency for similar reasons. The third party thus sought legal certainty that any pending divisional applications could not eventually give rise to a valid patent which could then be enforced against it.

The judge, however, dismissed this request, holding that this is not the purpose of Arrow declarations. This case therefore provides greater certainty regarding the circumstances under which Arrow declarations will, and will not, be granted.

Purpose

In the written reasoning for the decision, the judge explained that Arrow declarations are essentially statements by the court that a particular product or a particular process was not novel and/or not inventive at a particular date. Thus, such declarations provide a reasonable degree of certainty that commercialisation of that product or process will never be held to infringe a granted patent having an earliest priority date on or after the date mentioned in the declaration.

Arrow declarations are thus valuable tools for those seeking to commercialise a product or process without fear of being sued for patent infringement.

The judge then contrasted this purpose of Arrow declarations with the declaration sought by the third party in the present case. Specifically, the judge held that whilst Arrow declarations can provide third parties with certainty regarding the likelihood of their products and processes being held to infringe another party’s patent, it is not for the courts to decide whether such a patent should be granted in the first place. Instead, that remains a decision for patent examiners at the relevant patent office.

Conclusions

This decision will come as little surprise to those familiar with the patent application process. In particular, patent applications can be amended to address an examiner’s objections, and thus a decision to revoke a patent for invalidity does not necessarily mean that any divisional applications derived therefrom will suffer from the same problems. Thus, each patent application must be examined on its own merits, and only once the scope of the ensuing patent is known can the courts properly decide whether the patent was validly granted or not.

Additionally, the High Court’s decision demonstrates that, whilst Arrow declarations can be valuable commercial tools, such declarations are only likely to be granted in respect of a specifically defined product or process, and will not be granted to more generally declare that a certain patent application can never lead to grant of a valid patent. The decision also confirms that novelty and inventive step are relevant factors when deciding whether to grant an Arrow declaration, but sufficiency of disclosure is not.

Finally, this decision makes a clear distinction between (i) the role of patent examiners in deciding whether to grant a patent and (ii) the role of the courts in administering granted patents, and emphasises the reluctance of High Court judges to cross into patent examiners’ territory.