New referral to EPO over hidden internal structure or composition in prior art

Managing IP is part of Legal Benchmarking Limited, 1-2 Paris Gardens, London, SE1 8ND

Copyright © Legal Benchmarking Limited and its affiliated companies 2026

Accessibility | Terms of Use | Privacy Policy | Modern Slavery Statement

New referral to EPO over hidden internal structure or composition in prior art

Sponsored by

inspicos-400px recrop.jpg
molecules-3713741.jpg

Edward Farrington of Inspicos reports that guidance is being sought from the EPO Enlarged Board of Appeal three decades after a decision on the analysis of complex products

Patentees and patent applicants before the EPO are occasionally faced with prior art – for example, products which have been put on the market – the internal structure or composition of which is not clear without further investigation. In mechanical fields, such products might be devices or apparatuses which have to be disassembled or broken up to determine the contents. In the chemical field, such products might be polymers or similar chemical compositions, which are difficult or impossible to analyse.

Enlarged Board decision G 1/92 (OJ EPO May 1993) considered what “hidden properties” such products actually disclosed. Decision G 1/92 found that “[t]he chemical composition of a product is state of the art when the product as such is available to the public and can be analysed and reproduced by the skilled person… Where it is possible for the skilled person to discover the composition or the internal structure of the product and to reproduce it without undue burden, then both the product and its composition or internal structure become state of the art.”

Although decision G 1/92 is regularly relied upon by parties before the EPO, it did not clearly explain the meaning of the phrases “reproduce without undue burden”, “available to the public”, and “can be analysed”. Divergent case law has developed since G 1/92: some decisions requiring a high level of certainty when analysing hidden properties, others requiring a less complete analysis, and still other decisions excluding such disclosures from the state of the art altogether.

The Enlarged Board of Appeal (EBA) has therefore been asked to clarify some of the issues remaining after G 1/92 in a new referral, G 1/23.

In particular, the EBA will consider whether a marketed product can be excluded from the prior art if its composition or internal structure cannot be analysed. It will also consider whether technical information about a marketed product is state of the art, regardless of whether the composition or internal structure of the product can be analysed. The EBA is also being asked to clarify which criteria apply in determining whether the composition or internal structure of a product could be analysed and reproduced without undue burden.

It is hoped that decision G 1/23 will provide guidance as to which level complex products such as polymers must be analysed if they are to be considered state of the art.

more from across site and SHARED ros bottom lb

More from across our site

Mike Rueckheim reunites with 12 of his former Winston & Strawn colleagues as King & Spalding continues aggressive hiring streak
As global commerce continues to expand through e-commerce platforms and digital marketplaces, protecting brands has become a growing challenge for organisations worldwide. Counterfeiting, intellectual property infringement, and online brand abuse are increasing across industries, making brand protection strategies a critical priority for businesses.
Henrik Holzapfel and Chuck Larsen of McDermott Will & Schulte explain why a Court of Appeal ruling could promote access to justice and present a growth opportunity for litigation finance
A co-partner in charge says the UK prosecution teams are a ‘vital’ part of the firm’s offering, while praising a key injunction win
A team from White & Case has checked in on behalf of Premier Inn Hotels in a UK trademark and passing off case against a cookie brand
Litigation team says pre-trial work and a Section 101 defence helped significantly limit damages payable by ride-sharing firm Lyft in patent case
News of Avanci hiring a senior vice president and the EPO teaming up with a French AI startup were also among the top talking points
Explosm, the independent Texas studio behind the hit webcomic Cyanide & Happiness, partnered with Temu’s IP protection team to combat counterfeiters infringing on its brand
The latest in a dispute over juicing machines, and a shakeup in judicial compositions were also among the top developments
Patent partner Robert Hollingshead explains why the firm remains committed to Japan despite several US firms exiting the Japanese and greater Asia market
Gift this article