All applications with a filing date or international filing date on or after July 1, 2022, MUST file sequence listings in accordance with the new international standard, WIPO Standard ST.26 format.  This is implemented internationally starting July 1, 2022, including at the United States Patent & Trademark Office (“USPTO”), and the previous ST.25 format will eventually become obsolete.

WHAT ARE THE MAIN DIFFERENCES BETWEEN ST.25 AND ST.26?

The main difference between the two standards is that ST.25 is ASCII text format with numeric identifiers, whereas ST.26 is XML format with elements and attributes. 

Other changes found in ST.26 format include:

• D-amino acids, linear portions of branched sequences, and nucleotide analogs must be included. 
• Only the earliest priority application can be included.
• Only one applicant and optionally one inventor may be included. 
• Amino acid sequences are represented by one letter abbreviations.
• “t” represents uracil in RNA sequences and thymine in DNA sequences.  
• Sequences of less than 10 specifically defined nucleotides and less than 4 specifically defined amino acids are prohibited.

IS ST.25 OBSOLETE STARTING JULY 1, 2022?

No.  The filing date or international filing date will determine whether a sequence listing must comply with ST.25 or ST.26.  For example, U.S. national phase (under 35 U.S.C. § 371) applications filed after July 1, 2022, with an International PCT filing date before July 1, 2022, must file sequence listings that comply with ST.25.  All International PCT applications filed on or after July 1, 2022, must file sequence listings that comply with ST.26.

WHAT ABOUT CONTINUING APPLICATIONS THAT CLAIM PRIORITY TO AN APPLICATION FILED BEFORE JULY 1, 2022?

ST.25 formatted sequence listings must be converted to ST.26 format in all continuation and divisional applications filed on or after July 1, 2022.  All USPTO applications with benefit or priority to an application filed prior to July 1, 2022 (under 35 U.S.C. § 119, 120, 121, or 365)are required to file the sequence listing in ST.26 format starting July 1, 2022.  Thus, benefit or priority claim has no bearing on which sequence listing format to use – there is no “grandfathering.”

HOW DO YOU FILE A ST.26 XML SEQUENCE LISTING AT THE USPTO?

ST.26 sequence listings in XML format must be filed electronically with the USPTO through Patent Center or on physical media.  Importantly, EFS-Web will not permit submission of ST.26 XML files.

WHAT HAPPENS IF A ST.25 ASCII TEXT FORMATTED SEQUENCE LISTING IS FILED WITH AN APPLICATION FILED AFTER JULY 1, 2022?

If the application is improperly filed with a ST.25 ASCII text sequence listing, it will not be considered part of the application.  However, we understand that patent offices have safeguards in place wherein the applicant will be invited to confirm that the content of the ST.25 text format sequence listing should be additional sheets to the main part of the description.  This could result in application size fees for excess pages. 

In addition, if you update an international PCT application later with a proper ST.26 formatted sequence listing, this may affect your PCT filing date.  However, at the USPTO if a ST.25 ASCII text sequence listing is erroneously filed, a Notice to Comply with the Sequence Rules will be issued, which will provide the applicant an opportunity to file a proper ST.26 sequence listing.

WHERE CAN I FIND MORE INFORMATION?

The USPTO has developed a Sequence Listing Resource Center: https://www.uspto.gov/patents/apply/sequence-listing-resource-center. 

Here you can find USPTO final rules (see 87 Fe. Reg. 30806; 37 C.F.R. § 1.831-1.835; and 37 C.F.R. § 1.821-1.834), software for generating ST.26 sequence listings (WIPO Sequence), and additional guidance.