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Changes to sequence listing format at WIPO in 2022

Posted: August 12, 2021

Where patent applications involve sequence information, such as nucleotide or amino acid sequences of genes, the patent application should usually contain a sequence listing.

Sequence listings must be in a specific format.  The current standard for international (PCT) applications is WIPO Standard ST.25.

However, the standard is fairly old and does not cover modern developments in the fields of biotechnology and bioinformatics.  For example, ST.25 does not cover nucleotide analogs, D-amino acids or branched sequences which are commonly used in patent applications today.  In addition, the ST.25 format is not compliant with the International Nucleotide Sequence Database Collaboration and therefore data can be lost when searched on public databases.  Different IP offices around the world also interpret and enforce WIPO ST.25 differently.

Therefore, the World Intellectual Property Office (WIPO) is introducing a new global standard and from 2022, sequence listings in PCT applications must conform to this new standard, WIPO Standard ST.26.

What does this mean?

The implementation date of WIPO ST.26 is currently 1 January 2022.  Therefore, any sequence listing in a PCT application filed from 1 January 2022 must conform to WIPO ST. 26.

WIPO ST.26 applies to PCT applications with a filing date as of 1 January 2022 (and not the priority date). Any applications with a filing date prior to 1 January 2022 must comply with ST.25 instead.

Although WIPO member states originally agreed to be compliant with WIPO ST.26 from 1 January 2022, some member states have requested postponement of this until 1 July 2022 due to the necessary preparations required.  A formal decision on the implementation date will be made at the upcoming WIPO General Assembly, held in October 2021.  Forresters will release a further update once the implementation date is decided.

What are the main changes?

WIPO ST.26 is an XML document (eXtensible Markup Language) with elements and attributes, which is very different from the text document with numeric identifiers currently required in WIPO ST.25.  The change to WIPO ST.26 aims to provide a uniform format of sequence listing data across member states that is both human and machine-readable for automated validation and data exchange and can be searched in publically available databases.

One of the main changes of ST.26 is that the sequence listing must not include any sequences having fewer than ten specifically defined nucleotides, or fewer than four specifically defined amino acids.

A “specifically defined” nucleotide or amino acid is any nucleotide other than those represented by “n” or “x”.  Only specifically defined residues count towards the new minimum length requirement in ST.26.

A summary of the main changes between ST.25 and ST.26 is set out in the table below:

WIPO has released a desktop tool to support the generation of ST.26 compliant sequence listing.  Our team have spent considerable time familiarising themselves with the new standard.  Therefore, your usual Forresters attorney will be ready to provide compliant sequence listings for our clients, when this comes into force in 2022.

If you have any questions about the changes to sequence listing format in PCT applications, please contact your usual Forresters attorney.