Arrow Declarations and Refrigerant Technology: Mexichem vs Honeywell

9 April 2020

The UK Court of Appeal has recently issued an interesting decision in Mexichem UK Limited vs Honeywell International Inc relating to Arrow declarations. This illustrates the availability of such declarations in patent cases relating to any technology and not just to life science inventions where they have previously been deployed by generic and biosimilar companies.

Arrow declarations are used by potential patent infringers to forestall future infringement actions based on yet-to-be granted divisional patents. Essentially the party seeks a declaration that their product (or process) was obvious at the effective date which therefore implies that any patent infringed by that product (or process) must necessarily lack inventive step. They are discussed in more detail in our earlier briefing on Fujifilm Kyowa Kirin Biologics v Abbvie Biotechnology Ltd.

Here Mexichem sought declarations that it was obvious in the light of the prior art to use two specific refrigerants (‘ze’ and ‘yf’) in the manufacture of a product for use in a mobile air-conditioning system (commonly used in cars). This was in the context of an application for revocation of six patents owned by Honeywell who also had at least four pending divisional applications before the EPO. Honeywell sought to have the application for the declarations struck out on the basis that they were not sought in relation to a specific product or process, were not sufficiently clear, and that declarations in these broad general terms lacks any utility.

The Court of Appeal rejected Honeywell's arguments allowing the issue to proceed to trial. They commented that the declarations are a means of ensuring that Mexichem will remain in procedural control of judicial proceedings whereby the court can determine whether or not the broad concepts at issue involve an inventive step. The declarations will also mean that Mexichem will obtain protection against further attempts by Honeywell to protect such broad concepts through divisional applications. It remains to be seen of course if Mexichem will actually succeed in obtaining such declarations when the case comes to trial.

The decision can be found here.

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