eCTD Module 1 Explained: US and EU Structure, Envelope and Pitfalls
eCTD Module 1, explained
The regional module: what goes in it, how the US and EU structures compare, how the envelope works, and where Module 1 causes most of a team’s rework.
The one module ICH left to the regions
Module 1 holds what each authority needs that is not harmonised: forms, cover letters, labeling, administrative information and correspondence. It also carries the envelope — the metadata that identifies the application and the sequence. Each region defines its own structure, its own backbone and its own vocabulary, which is why a product filed in five markets needs five Module 1s.
The twenty US sections
US regional DTD v3.3. The full guide adds the EU structure and a three-region envelope comparison.
Form 356h, 1571, 2253, 3674 and others
What the sequence contains and why
Contacts, certifications (debarment, financial disclosure), patent and exclusivity
Letters of authorization, rights of reference, cross-references
Withdrawal, inactivation, reactivation
Meeting requests, background packages, correspondence
Designation requests and rolling review
Requests by study type
Waivers, deferrals, pediatric study plans and requests
Requests and correspondence
Information not covered under Modules 2–5
Pre-IND, expanded access, waivers and general correspondence
Including the DSUR
Draft, final, listed-drug and investigational labeling
Correspondence and materials, with audience and material types
Including REMS
Commitments and requirements correspondence
Name review submissions
Emergency use authorization
Initial IND only
Where Module 1 goes wrong
Outdated forms
Authorities revise forms. An old version is a common technical query.
Misplaced correspondence
US meetings (1.6), information amendments (1.11) and other correspondence (1.12) are distinct sections.
Labeling lifecycle
Draft and final labeling sit in different US sections; replacing across them breaks the history.
Promotional metadata
US audience and material types are required attributes on 1.15.
Missing languages
EU product information must be present for every concerned member state.
Wrong country
In segmented regions (EU, GCC), a document under the wrong country reaches the wrong authority.
The full Module 1 guide
For publishers and regulatory operations teams.
- The twenty US Module 1 sections and what goes in each
- The EU Module 1 structure
- The envelope compared: US, EU and Japan
- Where Module 1 causes rework, and practices that help
Frequently asked
Why is Module 1 different in every region?
ICH harmonised Modules 2–5. Module 1 holds each authority’s own administrative and product-information requirements, so each region defines its own structure, backbone and vocabulary.
What is the eCTD envelope?
The Module 1 metadata that identifies the application, the submission and the sequence — application number and type, submission type, procedure, applicant and contacts. Most high-severity validation errors are envelope errors.
Where do meeting packages go in a US submission?
Module 1.6 — meeting requests in 1.6.1, background materials in 1.6.2 and related correspondence in 1.6.3.
Module 1 built from the region’s own rules
DnXT Publisher builds each region’s Module 1 and envelope from its specification and vocabularies, for 16 eCTD regions.
