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

Anthony O'Malley will replace Andrew Blattman at IPH, which owns several large IP firms across Australia, Asia and Canada
Barry Greenbaum, partner at Olshan Frome Wolosky, explains how in-house teams can update their approach to brand development, and where AI can add value
Christine Chiramel, who joins a full-service law firm after 17 years of working at specialist firms, says she’s excited to explore how corporate commercial issues are blurring into IP
Practitioners say increasing the pecuniary jurisdiction of India’s most popular IP litigation forum to around $2 million would spark unpredictability and make it difficult for SMEs to benefit
The Spain-based firm has appointed an industry veteran to lead the group, which it hopes will strengthen its ability to support clients in ‘disruptive technologies’
Shaina Haria, a final-seat trainee at an international law firm’s UK office, shares how she fell in love with IP and why the area of law has changed the way she views the world
Now in its sixth edition, the IP Case Law Conference was focussed on the notion of ‘growing through change’
Nick Redfearn and Khanh Nguyen of Rouse discuss Vietnam’s latest identification in the 2026 Special 301 Report and how the country is taking genuine steps to meet US expectations
Tatiana Campello reflects on 30 years of practising at the firm, and urges women IP attorneys to think beyond the day-to-day
A David v Goliath battle involving TikTok, and Via Licensing Alliance adding new members to its Voice Codec patent pool, were also among the top talking points
Gift this article