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

VO, which has offices in the Netherlands, Belgium and Germany, is the second European IP firm to secure external backing this week
The Bardehle Pagenberg attorneys-at-law discuss the firm’s Managing IP EMEA Awards 2026 success, Unified Patent Court litigation strategy, and evolving European patent trends
A patent battle between two legal tech companies and a loss for Elon Musk’s xAI against OpenAI were also among the top talking points
With drug prices a hot topic in the US, courts are seemingly more reluctant to prevent the entry of generics to the market
Academic Eden Sarid joins us during Pride Month to discuss queer expression and IP law, Patagonia v Pattie Gonia, and how queer and AI-generated creations both pose novelty concerns
Patent attorney Michael Henson joins the firm to lead its freshly launched blockchain and digital assets practice
A dispute over mammogram technology, and a development in the case between GSK and Moderna were also among the top talking points in recent weeks
With rankings for Western Europe set to be published on June 25, we sat down with our research lead to find out what practitioners and law firms can expect
Peter O’Sullivan, a professional services executive, says he is looking forward to helping Pearce IP become the leading life sciences firm in Australia and New Zealand
Matteo Di Lernia, advocate at LCA Studio Legale, unpicks the CJEU’s ruling in M.M. Ristorazione v Villa Ramazzini, including its impact on litigation strategies
Gift this article